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Sample records for acidos adenilico uridilico

  1. The preparation of nucleotides uniformly labelled with carbon-14 by biosynthetic methods. Isolation of adenylic, uridylic, cytidylic,and guanylic acids, from the alkaline hydrolysate of escherichia coli RNA; Preparacion de nucleiotidos uniformemente marcados con 14{sup C}, por via biosintetica. Aislamiento de los acidos adenilico, uridilico, citidilico y guanilico, procedentes de la hidrolisis alcalina de RNA de escherichia Coli.

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Pineda, M D; Pacheco Lopez, J

    1978-07-01

    A method is described for the preparation and analysis of adenylic, uri dilic, cytidi- 11c and guanylic acids, labelled with 14{sup C}. Escherichia coli cells have been labelled by growing them in a medi dia containing glucose-14{sup C} as their only source of carbon. RNA is isolated from the cells, and after hydrolysis of the molecule the resulting nucleotides are separated by gel filtration and exchange chromatography. Chemical and radiochemical purity of the Isolated nucleotides is determined, and also its specific radioactivity. (Author) 30 refs.

  2. Enfermedad acido-peptica

    OpenAIRE

    Echavarría, Hector Raúl; Fundación Valle de Lili; Mendoza, Alfredo

    1999-01-01

    ¿En qué consisten las enfermedades que se denominan con el término genérico de enfermedad acido-péptica?/ ¿Cuáles son sus síntomas?/ ¿Cómo se comporta la enfermedad acido-péptica y cuáles son sus causas?/ ¿Cómo se evitan estas enfermedades y como se tratan?

  3. Azione citodifferenziante ed antitumorale dell'acido ellagico

    OpenAIRE

    Vanella, Luca

    2011-01-01

    Il lavoro ha lo scopo di valutare l'effetto citodifferenziante ed antitumorale dell'acido ellagico in tre diverse linee cellulari prostatiche a diverso grado di invasivita' (DU145, LnCap, BPH1). I risultati della Cromogranina A e della P75 NGRF, ottenuti mediante immunofluorescenza, evidenziano un'azione citodifferenziante dell'acido ellagico in maniera dose dipendente. Inoltre i risultati dimostrano come l'acido ellagico abbia la capacita' di ridurre, in maniera dose dipendente, sia l'espres...

  4. Cross linkage studies with the membranes of the vesicular stomatitis virus using radioactive 4-acido and 5-acido palmitic acid

    International Nuclear Information System (INIS)

    Verfondern, M.

    1983-01-01

    In the study described here the spatial arrangement of lipids and proteins in the VS virus was investigated on the basis of the covalent cross linkage technique. The formation of such cross linkages is brought about by the action of photosensitive acidosubstituted lipids, which permit acido functions to be introduced into a membrane in a previously defined position. Subsequently, photolysis helps to trigger the generation of radioactive nitrenes that react with the proteins and lipids in their immediate vicinity in a direct and non-selective way. The findings revealed by this study have raised questions as to the possibility of lipid-protein and lipid-lipid interactions, which is also discussed. (orig./MG) [de

  5. Interchange reaction of disulfides and denaturation of oxytocin by copper(II)/ascorbic acid/O2 system.

    Science.gov (United States)

    Inoue, H; Hirobe, M

    1987-05-29

    The interchange reaction of disulfides was caused by the copper(II)/ascorbic acid/O2 system. The incubation of two symmetric disulfides, L-cystinyl-bis-L-phenylalanine (PP) and L-cystinyl-bis-L-tyrosine (TT), with L-ascorbic acid and CuSO4 in potassium phosphate buffer (pH 7.2, 50 mM) resulted in the formation of an asymmetric disulfide, L-cystinyl-L-phenylalanine-L-tyrosine (PT), and the final ratio of PP:PT:TT was 1:2:1. As the reaction was inhibited by catalase and DMSO only at the initial time, hydroxyl radical generated by the copper(II)/ascorbic acid/O2 system seemed to be responsible for the initiation of the reaction. Oxytocin and insulin were denatured by this system, and catalase and DMSO similarly inhibited these denaturations. As the composition of amino acids was unchanged after the reaction, hydroxyl radical was thought to cause the cleavage and/or interchange reaction of disulfides to denature the peptides.

  6. Acido-basic control of the thermoelectric properties of poly(3,4-ethylenedioxythiophene)tosylate (PEDOT-Tos) thin films

    DEFF Research Database (Denmark)

    Khan, Zia Ullah; Bubnova, Olga; Jafari, Mohammad Javad

    2015-01-01

    study the variation in the thermoelectric properties by a simple acido-basic treatment. The emphasis of this study is to elucidate the chemical changes induced by acid (HCl) or base (NaOH) treatment in PEDOT-Tos thin films using various spectroscopic and structural techniques. We could identify changes...... in the nanoscale morphology due to anion exchange between tosylate and Cl- or OH-. But, we identified that changing the pH leads to a tuning of the oxidation level of the polymer, which can explain the changes in thermoelectric properties. Hence, a simple acid-base treatment allows finding the optimum...

  7. Peracetic acid as disinfectant of municipal wastewaters; L'acido peracetico nella disinfezione dei reflui urbani

    Energy Technology Data Exchange (ETDEWEB)

    Funari, E. [Istituto Superiore di Sanita' , Laboratorio di Igiene Ambientale, Reparto di Medicina Ambientale, Rome (Italy); Lopez, A. [Consiglio Nazionale delle Ricerche, Istituto di Ricerca sulle Acque, Reparto di Chimica e Tecnologia delle Acque, Bari (Italy)

    2000-09-01

    Based on the currently available literature, this paper is aimed at providing a sort of the <> on the use of peracetic acid (C{sub 3}COOOH{identical_to} Paa) as disinfectant of biologically treated municipal wastewater: the growing interest for this substance, used since many years in other sectors (e.g., food-industry, breweries, etc.) is mainly due to the claimed limited formation, if any, of harmful disinfecting by-products (Dbp) with consequent lack of toxicity in Paa treated wastewaters. Such features are just the opposite of those of chlorine, i.e. the most used disinfectant for municipal wastewater. During chlorine-disinfecting, in fact, numerous harmful organo-chlorinated Dbp are formed and, accordingly, the toxicity of chlorinated effluents results very high. In spite of the above reported <> properties of Paa, its use at large scale facilities is still restricted and this not only because of its costs but even for the limited knowledge concerning: the actual disinfecting effectiveness towards different pathogens, the nature and the toxicological properties of its potential Dbp, and the disinfecting performances at large scale facilities. The present paper, besides reporting an extensive and useful collection of references concerning Paa, provides a critical review on the current knowledge regarding specific Paa features such as: its disinfecting effectiveness towards different pathogenic micro-organisms, the nature and the toxicity of its disinfecting by-products, the environmental impact of Paa treated effluents, and the operative conditions used at large scale wastewater treatment plants. [Italian] Il presente lavoro, basandosi sui dati disponibili in letteratura, si propone di fare il punto sull'impiego dell'acido peracetico (CH{sub 3}COOOH{identical_to} PAA) come disinfettante di reflui urbani depurati. Il crescente interesse nei confronti di questa sostenza, gia' nota come disinfettante in

  8. Modificación estructural de Poli(Acido Láctico) (PLA) mediante extrusión reactiva: estudio preliminar en mezclador interno escala laboratorio

    OpenAIRE

    Espejo, Lucas

    2011-01-01

    Doble titulació Este proyecto, realizado en Centro Catalá del Plástico y por lo tanto implicado en el dominio de los polímeros, pretende preparar y caracterizar sistemas de Acido Poli(Láctico) (PLA) con extensores de cadena (CE) que serían adecuados y eficientes para el sector de los envases. Los procesos tal la Inyección y/o Extrusión empleando el PLA en este campo se enfrentan a la pérdida de las propiedades termo-mecánicas. Es el resultado de la degradación térmica y h...

  9. Wastewater disinfection with peracetic acid and UV; La disinfezione di acque reflue con acido peracetico e raggi ultravioletti

    Energy Technology Data Exchange (ETDEWEB)

    Caretti, C.; Lubello, C. [Florence Univ., Florence (Italy). Dipt. di Ingegneria Civile

    2001-06-01

    Was investigated the synergy between UV and peracetic acid (PAA) through a five months on-site experimental study in a pilot plant fed by the secondary effluent of the central wastewater treatment plant of Pistoia, Italy. This experiment is a part of a larger research project on advanced treatment for municipal wastewater reuse in agriculture. Because of Italy's strict limits on unrestricted wastewater reuse in agriculture (2 CFU total coliform/100 ml), a very high degree of disinfection is necessary. In the investigated experimental conditions, it has been impossible to meet such values through an exclusive use of UV irradiation (the UV unit reaches at most 4 Log inactivation). Low levels of PAA greatly enhance the decline of indicator levels, but higher unsustainable doses are required to hit the Italian limit. Through a poor amount of information on the subject was available in literature, it was tried to find out how the disinfection efficiency could improve by simultaneously using UV and PAA. It was found out that a combined treatment is satisfactory and that it is more advantage of the hydroxyl radicals formation due to the PAA photo lysis. The application of 2 ppm of PAA with an UV dose of 192 mWscm{sup -}2 is enough to meet the Italian limit. [Italian] Nel presente articolo si riportano i risultati di uno studio sulla sinergia tra acido peracetico (PAA) e raggi ultravioletti nella disinfezione delle acque reflue secondarie; le prove sono state effettuate su scala pilota, presso l'impianto centrale di Pistoia. Tale sperimentazione fa parte di un piu' ampio progetto di ricerca sulla possibilita' di riutilizzare le acque reflue a scopo irriguo; per rispettare i limiti estremamente stringenti imposti dalla normativa italiana per l'irrigazione (2 CFU Coliformi totali/100 ml, nel caso di irrigazione illimitata), e' necessario garantire efficienze di disinfezione molto elevate. Nelle condizioni sperimentali considerate, non e

  10. Hydrogen sulfide corrosion of weld regions in API X52 steel; Corrosion por acido sulfhidrico de las regiones de soldadura en acero API X52

    Energy Technology Data Exchange (ETDEWEB)

    Arenas-Martinez, L.F [Universidad Autonoma de Coahuila, Coahuila (Mexico)]. E-mail: fernando.arenas@uadec.edu.mx; Garcia-Cerecero, G. [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V., Saltillo, Coahuila (Mexico)

    2012-10-15

    The corrosion behavior of gas metal arc welding (GMAW) regions has been studied using potentiodynamic polarization and polarization resistance (LPR) techniques. Experiments were conducted in hydrogen sulfide (H{sub 2}S)-containing brine and in H{sub 2}S-free brine. Welds were made on API 5L X52 steel. Due to differences in their microstructure, chemical composition and residual stress level, weld regions exhibited different responses under H{sub 2}S corrosion. Base metal exhibited the highest corrosion rate (CR) and the most cathodic corrosion potential. [Spanish] Se estudio el comportamiento ante la corrosion de las regiones de soldadura de un cordon realizado por arco metalico con gas (GMAW) sobre un acero grado API X52 mediante las tecnicas de polarizacion potencio dinamica y resistencia a la polarizacion (LPR). Los experimentos se realizaron utilizando salmuera con 300 ppm de acido sulfhidrico (H{sub 2}S) y salmuera libre de H{sub 2}S como electrolitos. Debido a las diferencias en su microestructura, composicion quimica y el nivel de esfuerzos residuales, las regiones de soldadura mostraron diferentes respuestas a la corrosion por H{sub 2}S. El metal base exhibio la velocidad de corrosion (VC) mas alta y el potencial de corrosion mas catodico.

  11. ANALISIS DEL CO-TRATAMIENTO PASIVO DE AGUAS RESIDUALES MUNICIPALES Y DRENAJE ACIDO DE MINAS EN CERRO RICO DE POTOSÍ, BOLIVIA

    Directory of Open Access Journals (Sweden)

    William H.J. Strosnider

    2015-01-01

    Full Text Available El drenaje acido de minas (DAM es un problema a nivel mundial. El co-tratamiento pasivo de DAM con aguas residuales municipales (ARM es una manera efectiva y de bajo costo que utiliza los nutrientes de ARM para tratar las concentraciones de metales y sulfato en DAM. Cerro Rico de Potosí, Bolivia es una de las grandes ciudades mineras en el mundo que tiene muchos problemas con el DAM. El objetivo de este estudio fue determinar velocidades de reacción de Al, Fe, Mn, Zn, y otros metales en DAM provenientes de un flujo de agua en Cerro Rico usando un sistema reactor de tres etapas. El DAM tenía un pH de 3.58, acidez de 1080 mg/L equivalente a CaCO3 conteniendo concentraciones de 12, 68, 17, y 550 mg/L de Al, Fe, Mn y Zn respectivamente. Las velocidades de reacción de Al, Fe, Mn y Zn fueron de 1.43, 2.09, 0.01 y 0.10 d-1, respectivamente.

  12. ESTUDIO DE LA ADSORCIÓN DE PROTEÍNAS SOBRE SUPERFICIES DE ACIDO POLILÁCTICO MEDIANTE TÉCNICAS GRAVIMÉTRICAS Y ELECTROQUÍMICAS

    Directory of Open Access Journals (Sweden)

    HUGO ARMANDO ESTUPIÑAN DURAN

    2011-01-01

    Full Text Available Metodos electroquimicos fueron utilizados para promover y evaluar la adsorcion orientada de albumina y colageno sobre superficies polimericas de acido polilactico (PLA mediante la aplicacion de un sobrepotencial anodico en un rango de 0 V a 0,45 V. La adsorcion fueestudiada usando mediciones simultaneas de espectroscopia de impedancia electroquimica (EIE y microbalanza de cristal de cuarzo (QCM, en un rango de temperaturas de 25°C a 45°C, con variaciones en proteina entre 5 y 20 ¿Êg/ml en solucion buffer de fosfato de pH 7,4. Con el aumento de la concentracion de proteinas en el electrolito, disminuye la resistencia a la transferencia de carga, exhibiendo asi una mayor adsorcion sobre la superficie, ademas de aumentar la magnitud de los cambios de masa. Se mejoro la hidrofilicidad del recubrimiento, mostrando una mayor afinidad con las soluciones de colageno y por lo tanto un aumento en la biocompatibilidad debido a la activacion superficial.

  13. Determination of the load state of lead-acid batteries using neural networks; Determinacion del estado de carga de baterias plomo-acido utilizando redes neuronales

    Energy Technology Data Exchange (ETDEWEB)

    Cristin V, Miguel A; Ortega S, Cesar A [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2005-07-01

    The charge of lead-acid batteries (LAB), as in any other type of batteries, consists of replacing the energy consumed during the discharge. Nevertheless, as no physical or chemical process is good enough to totality recharge a battery, it is necessary to supply to it more than the 100% of the energy demanded during its discharge. A critical factor to make a suitable load control of the batteries is to determine its own state of load. That is to say, to have an efficient load control, it is necessary to count on means that allow to accurately determining the residual capacity of the battery to deliver load. This one is the one of the aspects of greater interest in the research centers around world. For this reason, in this work it was pretended to develop a calculation algorithm of the state of load of batteries based on a fuzzy-neural network that could calculate the state of load without using the battery current as an input. This is because one of the main problems for the designers of battery load controllers is the correct supervision of the current that circulates around the system in all the rank of operation of the same one because the sensors do not have a linear behavior. [Spanish] La recarga de baterias plomo-acido (BPA), como cualquier otro tipo de baterias, consiste en reponer la energia consumida durante la descarga. Sin embargo, como ningun proceso fisico o quimico es lo bastante eficiente para recargar a totalidad una bateria, es necesario suministrarle mas del 100% de la energia demandada durante su descarga. Un factor critico para realizar un adecuado control de carga de las baterias, es determinar su propio estado de carga. Es decir, para tener un control de carga eficiente, es necesario contar con un medio que permita determinar con precision la capacidad remanente de la bateria para entregar carga. Este es uno de los aspectos de mayor interes en los centros de investigacion alrededor el mundo. Por tal razon, en este trabajo se propuso

  14. The use of peracetic acid in drinking water systems: flow tests; L'acido peracetico in potabilizzazione: prove in flusso

    Energy Technology Data Exchange (ETDEWEB)

    Ragazzo, P. [Consorzio per l' Acquedotto del Basso Piave, San Dona' di Piave, VE (Italy); Navazio, G. [Padua Univ., Padua (Italy). Dipt. dei Processi Chimici dell' Ingegneria; Cavadone, A. [Solvay Chimica Italia S.p.A., Milan (Italy)

    2000-09-01

    In a previous research, a preliminary study was carried out on the disinfection efficiency of peracetic acid (PAA), comparing it to that of other disinfectants that are typically used, in batch tests with dosage values ranging from 0.5 to 5 ppm. The study was carried out on samples of water collected from several significant points of the treatment process at the main water treatment plant in Jesolo (Venice, Italy). On the basis of results (basically positive at that time) obtained from these tests, a 400 litre/hour pilot plant was built, as a lower scale reproduction of the drink water treatment system mentioned earlier, in order to study the characteristics of PAA even in tests that could more realistically simulate the flow of water along the process. These tests essentially confirmed the kinetics of the spontaneous hydrolysis to CH{sub 3} COOH+H{sub 2}O{sub 2} and those of dismutation to CH{sub 3}COOH+O{sub 2}, with half-life time values ranging from 3 to 12 hours, depending on the characteristics of the water (especially the pH factor) and the PAA concentration values. [Italian] In un precedente lavoro e' stato effettuato un preventivo studio sull'efficienza disinfettiva dell'acido peracetico, anche in confronto con gli altri piu' usuali disinfettanti, in prove condotte in batch, con dosaggi compresi tra 0.5 e 5 ppm, su campioni di acqua prelevati dai diversi punti significativi della linea di trattamento della centrale di Jesolo (Torre Caligo), gestita dal Consorzio Acquedottistico del Basso Piave di S. Dona' di Piave (Venezia). Sulla base dei risultati, sostanzialmente positivi, e' stato costruito un impianto pilota da 400l/h, riproducente, in scala, la linea di potabilizzazione su ricordata, per studiare le caratteristiche del PAA anche in prove piu' probanti condotte in flusso. In tali prove sono state sostanzialmente riconfermate le cinetiche delle reazioni spontanee di dirolisi a CH{sub 3}COOH+H{sub 2}O{sub 2} e di

  15. Proposal to neutralize acid fluids from wells in the Los Humeros, Pue., geothermal field; Propuesta para la neutralizacion de fluidos acidos provenientes de pozos del campo geotermico de Los Humeros, Pue.

    Energy Technology Data Exchange (ETDEWEB)

    Flores Armenta, Magaly del Carmen; Ramirez Montes, Miguel; Garcia Cuevas, Juan Manuel [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: magaly.flores@cfe.gob.mx

    2009-07-15

    Neutralizing an acidic fluid consists of adding a sodium hydroxide solution to neutralize the H group of acids, therefore increasing the pH. The injection of sodium hydroxide has to be continuous and at a proper depth inside the well to protect against the corrosion of casing and surface equipment. Neutralization is a common practice used in geothermal fields, such as at The Geysers in the US and Miravalles in Costa Rica-places where aggressive fluids cause problems for extracting and using geothermal fluids commercially. A zone surrounding wells H-4, H-16 and H-29 in the northern section of the Los Humeros, Pue., geothermal field, known as the Colapso Central, has shown evidence of aggressively acidic fluids. Several wells drilled in the area had to be repaired, thus plugging and isolating the deepest production zones. Well H-43 was drilled two years ago in the northern zone of the field, and even though it is not located in the aggressive-fluid zone, the well presents mineralogical features possibly indicating the presence of acidic fluids. Therefore, before producing this well it has been proposed we install a neutralization system with general characteristics presented in this paper. The system will prevent corrosion that up to now has prevented exploitation of the deep portion of Colapso Central, helping to develop the field in a more profitable way. [Spanish] Neutralizar un fluido acido consiste en agregarle una solucion de hidroxido de sodio. Esto neutraliza el grupo de acidos H y en consecuencia aumenta el pH. La inyeccion de hidroxido de sodio se realiza de manera continua y a una profundidad adecuada dentro del pozo para proteger a la tuberia y a todo el equipo superficial contra la corrosion. La neutralizacion es una practica comun que se viene realizando en campos como Los Geysers en Estados Unidos y en Miravalles, Costa Rica, donde la presencia de fluidos agresivos causa problemas en la extraccion y aprovechamiento del fluido geotermico con fines

  16. Synthesis and characterization of PdAg as a catalyst for oxygen reduction reaction in acid medium; Sintesis y caracterizacion de PdAg como catalizador para la reaccion de reduccion de oxigeno en medio acido

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Casillas, D. C.; Vazquez-Huerta, G.; Solorza-Feria, O. [Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: dcmartinez@cinvestav.mx

    2009-09-15

    This work presents the synthesis of the binary compound PdAg and the electrochemical characterization for oxygen reduction reaction (ORR) in acid medium. The catalyst is obtained from the reduction of Pd(NO{sub 3}){sub 2}·2H{sub 2}O and AgNO{sub 3} with NaBH{sub 4} in THF. The synthesized compound was physically characterized with transmission electron microscopy (TEM), sweep electron microscopy (SEM) and x-ray diffraction (XRD) of powder. Electrochemical studies were conducted to determine the catalytic activity and intrinsic properties of the PdAg material for the ORR in acid medium using cyclic voltamperometry (CV), rotary disc electrode (RDE) and electrochemical impedance spectroscopy (EIS) in a solution of H{sub 2}SO{sub 4} 0.5 M at 25 degrees Celsius. The electrochemical current-potential responses were compared to those of palladium and platinum. The kinetic results showed an increase in the performance of the bimetallic electrocatalyst containing Ag as compared to pure Pd, but less than that obtained with nanometric Pt. The Tafel slopes obtained are roughly120 mV dec-1, similar to that reported for Pt and Pd and for other Ru-based electrocatalysts. [Spanish] En este trabajo se presentan la sintesis del compuesto binario PdAg y su caracterizacion electroquimica para la reaccion de reduccion de oxigeno (RRO) en medio acido. El catalizador se obtuvo a partir de la reduccion de Pd(NO{sub 3}){sub 2}·2H{sub 2}O y AgNO{sub 3} con NaBH{sub 4} en THF. El compuesto sintetizado se caracterizo fisicamente por microscopia electronica de transmision (MET), microscopia electronica de barrido (MEB) y difraccion de rayos X (DRX) de polvos. Se realizaron estudios electroquimicos para determinar la actividad catalitica y las propiedades intrinsecas del material de PdAg para la reaccion de reduccion de oxigeno (RRO) en medio acido, utilizando las tecnicas de voltamperometria ciclica (VC), electrodo disco rotatorio (EDR) y espectroscopia de impedancia electroquimica (EIE), en

  17. Changes of arterial blood pressure, heart rate, internal body temperature, and blood acido-basic balance in the unanaesthetized rabbit following whole-body gamma irradiation at a mean absorbed dose of 250 rads

    Energy Technology Data Exchange (ETDEWEB)

    Dufour, R.; Court, L.

    1973-09-01

    The general effects of whole-body gamma -irradiation at a mean absorbed dose of 250 rads were studied simultaneously in the unanaesthetized rabbit for 48 hours. They occurred early, with the following characteristics: arterial blood pressure decreased steadily as early as the 2nd hour and reached its minimum value on the 5th hour with a decrease of about 14%; it remained low during the following two days. Heart rate increased during the first hour, was the highest by the end of the second hour, and resumed normal value on the 24th hour. Internal body temperature increased during the 1st hour and was maximum by the end of the 2nd hour, with a mean increase of 1.2 deg C; hyperthermia steadily decreased between the 4th and the 6th hours and had completely disappeared by the 24th hour. Respiratory alkalosis is shown in the acido-basic balance by a raise of pH, a decrease of PCO/sub 2/ and arterial blood bicarbonates. These various changes seem to indicate a double origin, both central and peripheral. (FR)

  18. Results of test of acid fluids neutralization in the well H-43, Los Humeros geothermal field, Puebla; Resultados de la prueba de neutralizacion de fluidos acidos en el pozo H-43, campo geotermico de Los Humeros, Puebla

    Energy Technology Data Exchange (ETDEWEB)

    Flores Armenta, Magaly del Carmen; Ramirez Montes, Miguel; Sandoval Medina, Fernando; Rosales Lopez, Cesar [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: magaly.flores@cfe.gob.mx

    2011-07-15

    The well H-43 was drilled in Los Humeros Geothermal Field, Pue., in 2007 and 2008. When well production was measured, it was found the well produced acid fluids with high corrosion potential. Then it was decided to try to neutralize the acidity of the H-43 fluids by adding a solution of sodium hydroxide. This is a basic substance used to neutralize mainly the acid groups H+, and the goal was to raise the pH of the fluids to minimize its corrosive features. First sodium hydroxide was injected into the well to protect the casing of 244.4 mm (9 5/8 in) against corrosion and then all the surface installations. It was possible to increase the pH of the well fluid from 5.2 up to 6.8 without altering the steam production, thus demonstrating the neutralization procedure is feasible. The approximate costs of the neutralization tests performed, including equipment for the proposed neutralization system, the neutralizer (NaOH), and drilling the well are about 71.4 million pesos (around 5.5 million USD). We estimate a benefit/cost ratio of 1.5 and a return on investment in five years, considering the income from energy sales at present value. [Spanish] El pozo H-43 fue perforado en el campo de Los Humeros, Pue., en 2007-2008, y al evaluar su produccion se encontro que producia fluidos acidos de alto potencial corrosivo. Se decidio por tanto realizar una prueba para neutralizar la acidez de los fluidos de este pozo, que consistio en agregarle una solucion de hidroxido de sodio. Esta es una sustancia basica que neutraliza principalmente los grupos acidos H+, con lo que se buscaba aumentar el pH del fluido lo necesario para reducir al maximo su caracter corrosivo. La inyeccion del hidroxido de sodio se realizo dentro del pozo a fin de proteger de la corrosion a la tuberia de revestimiento de 244.4 mm (9 5/8 pulgadas), y posteriormente a todos los equipos superficiales. Como resultado de la prueba, se logro aumentar el pH del fluido producido por el pozo de 5.2 a un maximo de 6

  19. REVIEW. BACTERIAS ACIDO LÁCTICAS: PAPEL FUNCIONAL EN LOS ALIMENTOS BACTÉRIAS ÁCIDO LÁCTICAS: PAPEL FUNCIONAL NOS ALIMENTOS REVIEW LACTIC ACID BACTERIA: FUNCTIONAL ROLE IN THE FOODS

    Directory of Open Access Journals (Sweden)

    RICARDO ADOLFO PARRA HUERTAS

    2010-06-01

    Full Text Available Las bacterias ácido lácticas han sido importantes en los alimentos por siglos por su considerable contribución al valor de los productos. Debido a varias de sus propiedades metabólicas, las bacterias ácido lácticas desempeñan un papel importante en la industria alimentaria, por su contribución significante al sabor, olor, textura, características sensoriales, propiedades terapéuticas y valor nutricional de los productos alimentarios. Este grupo está compuesto de un número de géneros incluyendo Lactococcus, Lactobacillus, Enterococcus, Streptococcus, Leuconostoc y Pediococcus. Algunos de los metabolitos producidos por las este tipo de bacterias son ácidos orgánicos, sustancias preservantes, polisacáridos, vitaminas, endulzantes, olores y sabores entre otros. Esta revisión se enfoca en estudiar la importancia de las bacterias acido lácticas en los alimentos.As bacterias ácido lácticas têm sido importantes nos alimentos por séculos pela sua considerável contribuição ao valor dos produtos. Devido a varias das suas propriedades metabóllcas, as bacterias ácido lácticas desempenham um papel importante na industria alimentar, pela sua contribulção significante ao sabor, cheiro, textura, características sensoriais, propriedades terapêuticas e valor nutrlcional dos produtos alimentar. Este grupo está constituido de um número de gêneros incluindo Lactococcus, Lactobaclllus, Enterococcus, Etreptococcus, Leuconostoc e Pediococcus. Alguns dos metabolltos produzidos por este tipo de bacterias são ácidos orgãnicos, sustãncias preservadoras, poli-sacáridos, vitaminas, adoçantes, cheiros e sabores entre outros. Esta revisão se enfoca em estudar a importãncia das bacterias ácido lácticas nos alimentos.Lactic acid bacteria have been important in food for centuries for their significant contribution to product value. Because several of its metabolic properties, lactic acid bacteria play an important role in the food

  20. Utilisation of chlorine-dioxide and peracetic acid as disinfectants of effluents from Bologna waste water treatment plant; Sperimentazione di tecniche di disinfezione mediante biossido di cloro e acido peracetico applicate alle acque reflue dell'impianto di trattamento della citta' di Bologna

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, M.L. [Bologna Univ., Bologna (Italy). Dipt. di Ingegneria delle Strutture, dei Trasporti, delle Acque, del Rilevamento e del Territorio; Sorrentino, M.

    2000-01-01

    The necessity to optimize the disinfection phase in the treatment plant of waste water of Bologna made possible an experimental survey about the efficacy of two disinfectant agents utilized: chlorine-dioxide and peracetic acid. Object of the survey is to verify the possibility of utilize, full scale, also peracetic acid as disinfection agent. The experimentation regarded the reals flows adduced and discharged from the plant and it may be an useful reference to verify performance of post-treatment constructed wetlands. Particularly it has been possible to assay the efficacy of the different treatment in waste water with residual concentrations of suspended solids. [Italian] La necessita' di ottimizzare la fase di disinfezione nell'impianto di trattamento acque reflue della citta' di Bologna, sia per il miglioramento delle rese di inattivazione, sia per la riduzione dei costi di esercizio, ha reso necessaria un'indagine sperimentale sull'efficacia di due agenti disinfettanti utilizzati: il biossido di cloro e l'acido peracetico. Scopo dell'indagine e' quello di verificare la possibilita' di impiegare, a scala reale, per il refluo tipico dell'impianto di Bologna, anche l'acido peracetico quale agente di disinfezione. La sperimentazione, condotta ha interessato le portate reali addotte e scaricate dall'impianto e puo' costituire un riferimento utile verificare la fattibilita' igienico-sanitaria di post-trattamenti di lagunaggio o fertirrigazione. In particolare si e' potuta saggiare l'efficacia dei diversi sistemi di trattamento sui reflui aventi concentrazioni residue non trascurabili di solidi sospesi.

  1. Determinación del acido abscisico en papa (Solanum sp. como respuesta a bajas temperaturas Abscisic acid determination in potato (Solanum sp. as a response to low temperature

    Directory of Open Access Journals (Sweden)

    Ortiz Luz Yineth

    2001-12-01

    Full Text Available En Colombia, existen importantes áreas con amplio potencial
    agrícola, las cuales presentan restricciones ambientales para su utilización durante determinadas épocas del año, a causa de las heladas que provocan las bajas temperaturas. Éste es el caso del Altiplano Cundiboyasence, en el cual el fenómeno en mención afecta, drásticamente, los cultivos hasta ocasionar disminución del rendimiento o perdidas totales. El presente trabajo tuvo como finalidad detectar la presencia de Acido Abscísico (ABA en las siguientes variedades de papa de la especie Solanum sp.: 'Capiro', 'Única', 'Chitagá', 'Morita', 'Pastusa', 'ICA-Zipa' y 'Nativa' (silvestre. El análisis se hizo en el estadio de prefloración bajo condiciones de temperatura ambiente (-20°C y expuestas a una simulación de helada (-4°C. Para la extracción de ABA, se recolectaron hojas del tercio superior de la planta y se sometieron a extracción Líquido-Líquido y, para su cuantificación, se utilizó el bioensayo de la inhibición del coleóptilo de trigo (Triticun tensa vulgare L., el cual se realizó por cromatografía de capa fina. Entre las variedades estudiadas, se obtuvieron dos grupos de respuesta: susceptibles y tolerantes, las cuales están asociadas con la posible ausencia o presencia de ABA. En las variedades 'ICA-Zipa' y 'Chitagá' no se detectó la presencia de ABA, como tampoco, se observó tolerancia a las bajas temperaturas. En las variedades 'Capiro', 'Pastusa', 'Nativa', 'Única' y 'Morita', se observó mayor tolerancia a las bajas temperaturas.
    There are many important geographical areas in Colombia with a high agricultural potential. They have environmental
    constrains, however, to be used in certain periods during the
    year because of the low temperature. This happens in the
    Cundiboyasence plateau, in which, this phenomenon affects
    dramatically the growing of potato crops up to the point of
    causing a decrease in production or

  2. The Use of Tritium-Labelled Thymidine in Studies on the Synthesis of Deoxyribonucleic Acids; Emploi de la Thymidine Tritiee Dans L'etude de la Synthese de l'Acide Desoxyribonucleique; 0418 0441 043f 043e 0414 ; Empleo de Timidina Tritiada para Estudiar la Sintesis de los Acidos Desoxirtibonucleicos

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, P. A.; Crathorn, A. R.; Shooter, K. V. [Chester Beatty Research Institute, Institute of Cancer Research, London (United Kingdom)

    1962-02-15

    balayage continu. Les deux methodes de mesure ont donne des resultats sensiblement differents. Pour chaque cellule, l'activite due au tritium, calculee d'apres les autoradiographies, a toujours paru superieure a celle de l'ADN isole. En mesurant ensuite a l'aide du compteur a balayage continu l'activite de cellules entieres, apres lavage et homogeneisation, on a obtenu des chiffres qui concordaient avec les resultats de l'autoradiographie. Il semble donc, en l'occurrence, que l'autoradiographie ne permette pas de mesurer de maniere satisfaisante la synthese de l'ADN. On a etudie l'activite associee, autre que celle de l'ADN, et entrepris sur d'autres types de cellules des etudes analogues de l'activite totale due au tritium et de l'activite de l'ADN isole; des effets similaires ont ete observes. A partir de ces donnees, on a pu distinguer plusieurs phases dans le processus de synthese : 1 Degree-Sign incorporation initiale de la thymidine a la cellule; 2 Degree-Sign phosphorylation en deux etapes au moins; 3 Degree-Sign formation d'ADN par polymerisation de la thymidine phosphorylee. Ainsi, on simplifierait a l'exces en supposant que l'incorporation de thymidine a la cellule permette de mesurer la synthese de l'ADN; il semble cependant qu'en utilisant cet indicateur on puisse obtenir des indications utiles sur les etapes preliminaires du processus. (author) [Spanish] En el curso de estudios sobre la biosintesis del acido desoxirribonucleico se han realizado algunos experimentos, utilizando celulas asciticas de Ehrlich, para investigar la fijacion e incorporacion de timidina-{sup 3}H. Despues de incubar in vitro las celulas marcadas con este compuesto, se han tomado autorradiografias de las mismas; tambien se ha aislado el acido desoxirribonucleico y se ha medido la actividad del {sup 3}H utilizando un contador de flujo. Al comparar los dos metodos de medicion, se advierte una marcada discrepancia; la actividad del {sup 3}H por celula, calculada a base de las

  3. Stability of RNA and DNA in Bone Marrow Cells, Demonstrated with Tritiated Cytidine and Thymidine; Emploi de la Cytidine et de la Thymidine Tritiees pour Demontrer la Stabilite de l'ARN et l'ADN dans les Cellules de la Moelle Osseuse; 0421 0442 0430 0414 ; Estudio de la Estabilidad de los Acidos Ribonucleico y Desoxirribonucleico de las Celulas de la Medula Osea, Utilizando Citidina y Timidina Tritiadas

    Energy Technology Data Exchange (ETDEWEB)

    Bond, V. P.; Feinendegen, L. E.; Cronkite, E. P. [Medical Research Centre, Brookhaven National Laboratory, Upton, Long Island, NY (United States)

    1962-02-15

    maniere que l'ADN. L'ARN et l'ADN de formation recente ne se diluent dans les cellules qu'a la faveur de la division cellulaire. (author) [Spanish] Los autores han estudiado el metabolismo de los acidos desoxirribonucleico y ribonucleico utilizando timidina tritiada (timidina-{sup 3}H), un precursor especifico del acido desoxirribonucleico, y citidina tritiada (citidina-{sup 3}H), un precursor comun de los acidos ribonucleico y desoxirribonucleico. Empleando citidina-{sup 3}H se determino autorradiograficamente la incorporacion diferencial por celula en los acidos ribonucleico y desoxirribonucleico, asi como en el espacio soluble. La misma determinacion se efectuo empleando metodos autorradiograficos y quimicos en el caso de poblaciones celulares, mediante extraccion diferencial aplicando un tratamiento apropiado con acido perclorico. Los estudios preliminares sobre renovacion realizados en celulas de HeLa con citidina-{sup 3}H pusieron de manifiesto la funcion precursora del acido ribonucleico nuclear respecto del acido ribonucleico citoplasmatico. La conservacion y distribucion del indicador en la fraccion acido ribonucleico es compatible con una mayor estabilidad de las macromoleculas de dicho acido. Asimismo, la incorporacion continua del indicador en la fraccion acido desoxirribonucleico es compatible con la presencia de un precursor de dicho acido en las ultimas fases de la sintesis. Fenomenos analogos se observaron en las celulas no maduras de la medula osea de la tata, estudiadas durante los dias consecutivos a la administracion de citidina-{sup 3}H por via intravenosa. La actividad del tritio en la fraccion soluble en acido y en las fracciones ARN y ADN se evaluo por metodos quimicos y autorradiograficos. Se comprobo que las tres curvas son paralelas desde el dia que sigue al de inyeccion y paralelas asimismo a las curvas de actividad del tritio en el acido desoxirribonucleico, cuando este se marca con timidina- {sup 3}H. La velocidad de disminucion de la

  4. The Radiation Induced Graft Copolymerization of Methacrylic Acid to Nylon; Copolymerisation par greffe de l'acide methacrylique sur le nylon, provoquee par irradiation; Obluchenie vyzyvaet graft-kopolimerizats yu metakrilovoj kisloty v nejlone; Injerto del acido metacrilico en el nylon por copolimerizacion radioinducida

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, R; Thomas, J K

    1960-07-15

    The grafting of methacrylic acid to nylon by the preirradiation technique has been studied. The rate of grafting is appreciably larger than that of homopolymerization. No simple relation exists between reaction rate and total dose. The temperature dependence of the rate of grafting to the fibre, preirradiated in air, indicates that initiation of grafting is likely to take place by decomposition of peroxide groups formed on irradiation. Electrical resistance measurements on the irradiated fibre indicate that this has been reduced by a factor of 10. (author) [French] On a etudie le greffage de l'acide methacrylique sur du nylon par la technique de preirradiation. La vitesse du greffage est sensiblement plus grande que celle de l'homopolymerisation. Il n'existe pas de rapport simple entre la vitesse de reaction et la dose totale. Le fait que la vitesse du greffage sur la fibre, pre-irradiee a l'air, depend de la temperature, indique que l'amorcage de la greffe est susceptible d'etre provoque par la decomposition des groupements de peroxyde formes lors de l'irradiation. Les mesures de resistance electrique effectuees sur la fibre irradiee indiquent que cette resistance a ete reduite au dixieme de la valeur originale. (author) [Spanish] Al estudiar la copolimerizacio n de injerto del acido metacrilico en el nylon por el procedimiento de preirradiacion, los autores comprobaron que la velocidad de injerto es sensiblemente mas elevada que la de homopolimerizacion. No existe una relacion sencilla entre la velocidad de reaccion y la dosis total. La influencia de la temperatura sobre la velocidad de injerto en la fibra previamente irradiada en aire indica que el proceso se inicia por descomposicion de los grupos peroxido formados durante la irradiacion. Las mediciones efectuadas demuestran que la resistencia electrica de la fibra irradiada solo alcanza la decima parte de la correspondiente a la fibra no tratada. (author) [Russian] Bylo provedeno izuchenie prosachivaniya

  5. Nucleic Acids and Protein Metabolism of Bone Marrow Cells Studied by Means of Tritiumlabelled Precursors; Etude du Metabolisme des Acides Nucleiques et des Proteines dans les Cellules de la Moelle Osseuse, a l'Aide de Precurseurs Trities; 0418 0437 0443 0414 ; Estudio con Ayuda de Precursores Tritiados del Metabolismo de los acidos Nucleicos y de las Proteinas en las Celulas de la Medula Osea;

    Energy Technology Data Exchange (ETDEWEB)

    Gavosto, F. [Istituto di Clinica Medica Generale e Centro di Studi Fisico-Biologici, Universita de Turin, Turin (Italy)

    1962-02-15

    . L'auteur examine ensuite la diminution et la dissociation du metabolisme de l'ARN et des proteines, dans les cellules de sujets atteints de leucemie aiguee, par rapport aux anomalies bien connues que presente le processus de maturation de ces cellules. (author) [Spanish] El autor examina las ventajas que presenta el empleo de los compuestos marcados con tritio en la tecnica autorradiografica. En efecto, los electrones emitidos por el tritio tienen una energia maxima de 0,018 MeV, que corresponde, aproximadamente, a un alcance de 1 miera en una emulsion fotografica y permiten, por lo tanto, lograr el maximo poder de resolucion al nivel celular y subcelular. Ello es particularmente util para estudiar fenomenos metabolicos en tejidos que se componen, como en el caso de la medula osea, de celulas de varios tipos en diversos estados de diferenciacion. Esta tecnica se ha aplicado al estudio del metabolismo de los acidos nucleicos y de las proteinas en las celulas normales y leucemicas de la medula osea. El metabolismo del acido desoxirribonucleico se ha estudiado utilizando un precursor especifico, la timidina-{sup 3}H. Comparando los elementos normales y leucemicos que han alcanzado un grado de madurez analogo, se han observado diferencias significativas en el porcentaje de celulas marcadas. Especialmente, en los casos de leucemia aguda, se ha comprobado que la incorporacion de timidina en las celulas leucemicas disminuye muy notablemente. Se estima que estos resultados constituyen una prueba de que la capacidad de proliferacion de estas celulas disminuye en comparacion con la de los mieloblastos normales. Por este mismo procedimiento, se ha estudiado el metabolismo del acido ribonucleico y de las proteinas, utilizando como precursores uridina-{sup 3}H, leucina-{sup 3}H y fenilalanina-{sup 3}H. Actualmente, en biologia celular se admite sin reservas la existencia de una estrecha relacion entre el metabolismo del acido ribonucleico y el de las proteinas. Ademas, se ha

  6. Isotopic data to study the mechanism of the oxidation of mercaptoacetic acid; Donnees isotopiques pour l'etude du mecanisme d'oxydation de l'acide mercaptoacetique; Izotopnyj metod issledovaniya mekhanizma okisleniya merkapgouksusnoj kisloty; Estudio del mecanismo de oxidacion del acido mercaptoacetico por medio de datos obtenidos con radioisotopos

    Energy Technology Data Exchange (ETDEWEB)

    Gal, D [Central Isotope Laboratory, University of Szeged (Hungary); Guczi, L [Department of Radiology, Elelmiszeripari Kutato Intezet, Budapest (Hungary)

    1962-03-15

    }S augmentait considerablement le taux d'absorption d'oxygene, tant dans le processus de catalysation par le fer qu'en l'absence de fer. Au cours de la reaction, on a mesure la concentration du sulfure, son activite specifique et son activite totale. En. partant de ces donnees, et en utilisant la methode d'etude cinetique au moyen d'isotopes, mise au point par Neiman et ses collaborateurs, on a pu calculer le taux de formation de sulfure et le taux de son oxydation ulterieure. La comparison de ces donnees avec d'autres donnees cinetiques revele que l'oxydation de l'acide mercaptoacetique en phase liquide est une reaction en chaine ramifiee, l'un des principaux elements de cette chaine etant la formation de Na{sub 2}S et son oxydation ulterieure. On a constate en outre qu'il se forme du sulfate, lors de la reaction, mais seulement a partir du sulfure mineral. Le fer catalyse la formation de disulfure organique et, de ce fait, influe aussi sur la formation de sulfure. (author) [Spanish] Numerosos investigadores han estudiado la autooxidacion en fase liquida, por oxigeno molecular, de compuestos que contienen un grupo mercaptano; si bien han llegado a la conclusion de que se forman sulfuros en el curso de la reaccion, el mecanismo exacto del proceso no se conoce. Los autores estudiaron la autooxidacion del acido mercaptoacetico a 50{sup o} C y pH 8 en presencia de complexon IV y de hierro. Anadieron al sistema Na{sub 2}S marcado con {sup 35}S y comprobaron que este compuesto aumenta notablemente la velocidad de absorcion de oxigeno tanto en las reacciones catalizadas por hierro como en las que transcurren en ausencia de iones de este metal. En el curso de la reaccion, los autores midieron la concentracion del sulfuro, su actividad especifica y su actividad total. Gracias a estos datos y empleando el metodo isotopico cinetico establecido por Neiman y colaboradores, pudieron calcular la velocidad de formacion del sulfuro y la velocidad de su oxidacion subsiguiente. Por

  7. SOSTITUTI BIOLOGICI VASCOLARI A BASE DI ACIDO IALURONICO

    OpenAIRE

    Pandis, Laura

    2014-01-01

    The discovery of an adequate tissue substitute for the regeneration of small vessels has become one of the most debated issues in the last years. This is due to recent advances in regenerative medicine, which offers new cellular types and biomaterials, and the large clinical applications that this product may have, ranging from the replacement of the coronary vessels to correction of peripheral vascular malformations in pediatric patients. The biomaterials used so far for large caliber vascul...

  8. Quercetin and its analogues: optical and acido-basic properties

    Czech Academy of Sciences Publication Activity Database

    Biler, M.; Biedermann, David; Valentová, Kateřina; Křen, Vladimír; Kubala, M.

    2017-01-01

    Roč. 19, č. 39 (2017), s. 26870-26879 ISSN 1463-9076 R&D Projects: GA MŠk(CZ) LD15082; GA MŠk(CZ) LTC17009 Institutional support: RVO:61388971 Keywords : QUANTUM-CHEMICAL CALCULATIONS * ALPHA-L-RHAMNOSIDASE * ANTIOXIDANT ACTIVITY Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

  9. LACTIC ACID BACTERIA WITH ANTIMICROBIAL ACTIVITY AGAINST PATHOGENIC AGENT CAUSING OF BOVINE MASTITIS BACTERIAS ACIDO LACTICAS CON ACTIVIDAD ANTIMICROBIANA CONTRA PATÓGENOS CAUSANTES DE MASTITIS BOVINA OUT BACTÉRIAS LÁTICAS COM ATIVIDADE ANTIMICROBIANA CONTRA OUT PATÓGENOS DA MASTITE BOVINA

    Directory of Open Access Journals (Sweden)

    LILIANA SERNA C

    2011-06-01

    Full Text Available The use of antibiotics to treat bovine mastitis, produces antibiotic residues in milk and decreased quality of dairy products. Lactic acid bacteria have been proposed as an alternative to avoid the use of antibiotics. This paper reports the antimicrobial activity against pathogens responsible of bovine mastitis, of 4 lactic acid strains isolated from cattle in a state of acidosis ruminal. It also evaluated the specific growth rate (m and antimicrobial activity of one of the strains, using two concentrations of carbon source (20 and 60 gl-1 in the commercial substrate MRS. The strains were biochemically identified as Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus fermen-tum and Weissella confusa. Weissella confusa showed the best antimicrobial activity against the major pathogens responsible of bovine mastitis. When has been used 60 gl-1 of total sugars in the fermentation substrate, was obtained diameter of inhibition of 31 mm for Staphylococcus aureus and 36 mm for Streptococcus agalactiae. The antimicrobial activity of Weissella confusa is superior antimicrobial activity reported by many other lactic acid bacteria, therefore Weissella confusa could potentially be used to prevent bovine mastitis.El uso de antibióticos para el tratamiento de mastitis bovina, genera residuos de antibióticos en la leche y disminuye la calidad de los subproductos lácteos. Las bacterias ácido lácticas se han propuesto como una alternativa para evitar el uso de antibióticos. En este artículo se reporta la actividad antimicrobiana contra patógenos productores de mastitis bovina, de 4 cepas acido lácticas aisladas de bovinos en estado de acidosis ruminal. Se evaluó además la velocidad especifica de crecimiento (m y la actividad antimicrobiana de una de las cepas, utilizando dos concentraciones de fuente de carbono (20 y 60 gl-1 en el sustrato comercial MRS. Las cepas se identificaron bioquímicamente como Lactobacillus acidophilus

  10. Study of apoptotic mechanisms induced by all-trans retinoic acid and its 13-cis isomer on cellular lines of human hepato carcinoma Hep3B and HepG2; Estudio de los mecanismos apoptoticos inducidos por el acido retinoico todo-trans y su isomero 13-cis en las lineas celulares de hepatocarcinoma humano Hep3B y HepG2

    Energy Technology Data Exchange (ETDEWEB)

    Arce Vargas, Frederick [Costa Rica

    2006-07-01

    of these cells to different chemotherapeutic agents. Survivin might decrease the answer of treatment by to be anti-apoptotic and even to change the apoptosis by other forms of cellular death (necrosis, mitotic catastrophe, etc.) doing that therapy be less efficient. Hep3B cells were sensitized with ATRA before to be treated with 5-FU and it was observed a more cytotoxicity than when every drug was used separately. Also there were required concentrations lower of both agents to produce cellular death. This effect didn't see with HepG2 cells. Although retinoids seem to be promising in the hepato carcinoma treatment, it must do more studies to improve the bioavailability and to decrease the unspecific toxicity of these drugs, including combinations with other agents, use of liposomes or synthesis of compounds with effects more selective that might be even directed to certain specific routes of cellular death. (author) [Spanish] Dos lineas celulares de cancer de higado (Hep3B and HepG2) se incubaron durante diferentes periodos de tiempo con varias concentraciones de dos isomeros del acido retinoico (ATRA y 13-cis AR) y con los agentes quimioterapeuticos 5-FU, cisplatino y paclitaxel. Se determino si estas sustancias inducian citotoxicidad, apoptosis y si modificaban la expresion de diferentes genes relacionados con la muerte celular por apoptosis, en parte para poder explicar la resistencia del carcinoma hepatocelular a estas drogas. Las celulas HepG2 mostraron mayor resistencia que las celulas Hep3B a las 72 horas de tratamiento, tanto el ATRA como el 13-cis AR fueron toxicos. Tambien se demostro que producian apoptosis en las dos lineas celulares. Este tipo de muerte celular parece estar mediada por una disminucion en la concentracion de Bcl-xL en las celulas Hep3B tratadas con ambos retinoides y un aumento en la concentracion de Bax en las celulas HepG2 tratadas con 13-cis AR. Se observo proteolisis de procaspasas 3 y 8 en las celulas Hep3B, sugiriendo activacion de

  11. The Treatment of Cancer by a Radioactive Drug: Tritium-Labelled Tetra-Sodium 2-Methyl-1:4-Naphthaquinol Diphosphate; Traitement du Cancer par un Remede Radioactif: Le Diphosphate Tetrasodique de Methyl-2 Naphtoquinone-1,4 Tritie; 041b 0435 0447 0435 043d 0414 ; Tratamiento del Cancer con la Sal Tetrasodica del Acido 2-Metil-1,4-Naftoquinon Difosforico Marcada con Tritio

    Energy Technology Data Exchange (ETDEWEB)

    Marrian, D. H.; Marshall, Barbara; Mitchell, J. S.; Simon-Reuss, I. [Department of Radiotherapeutics, University of Cambridge, Cambridge (United Kingdom)

    1962-02-15

    tetrasodica del acido 2-metil-l,4-naftoquinon-difosforico (''Synkavit'' Roche), asi como algunos de los metodos que se han empleado para marcar este y otros compuestos analogos. Sintetizaron el compuesto tritiado en forma de obtener una substancia radioquimicamente pura de 28 c/mmol (1 atomo de tritio por molecula) de actividad especifica. Demuestran que este producto penetra muy rapidamente en las celulas vivas, tanto in vivo como in vitro y que, en igualdad de condiciones los cultivos de celulas malignas incorporan en grado mucho mayor el compuesto marcado que los cultivos de celulas normales. Describen las investigaciones preliminares del empleo clinico de ese producto en casos avanzados de tumores malignos que suelen ser refractarios a otros tratamientos, observandose que la medula osea absorbe menor cantidad del compuesto que el tumor (en algunas ocasiones, hasta cinco veces menos). (author) [Russian] Dejstvie tetrasoda - 2-metil-1: 4- naftagidrohinondifosfata (Sinkavit - proizvodstvo Roshe) v kachestve radio- senitajzera obsuzhdaetsja narjadu s bolee rannimi metodami mechenija jetih i podob- nyh molekul. Sintez jetogo soedinenija, mechennogo tritiem, byl sdelan dlja togo, chtoby polu- chit' radiohimicheskoe chistoe lekarstvo s udel'noj aktivnost'ju v 28 kjuri/mil- limol' (odin atom tritija na molekulu). Budet pokazano, chto jeto soedinenie bystro vhodit v zhivuju kletku kak v este- stvennyh, tak i i laboratornyh uslovijah i chto kul'tury zlokachestvennyh kletok pogloshhajut mechenye atomy v gorazdo bol'shem ob{sup e}me, chem kul'tury normal'nyh kletok pri teh zhe uslovijah. Budut opisany predvaritel'nye issledovanija primenenija jetogo lekarstva na pacientah, imejushhih zlokachestvennye opuholi i nahodjashhihsja v tjazhelom ili neizlechimom sostojanii; usvoenie kostnym na kojefficient 5 mozgom nizhe, chem usvoenie opuhol'ju. (author)

  12. Tritiated Thymidine as Tracer in DNA Metabolism and Cell Dynamics of Experimental Myeloid Leukaemia; Emploi de la Thymidine Tritiee comme Indicateur pour l'Etude du Metabolisme de l'ADN et de la Dynamique des Cellules dans la Leucemie Myeloide Experimentale; 0422 0440 0438 0442 0414 ; Empleo de la Timidina Tritiada como Indicador para Estudiar el Metabolismo del Acido Desoxirribonucleico y la Dinamica Celular en la Leucemia Mieloide Experimental

    Energy Technology Data Exchange (ETDEWEB)

    Zajicek, G.; Rosin, A.; Gross, J. [Department of Experimental Medicine and Cancer Research, Hebrew University, Hadassah Medical School, Jerusalem (Israel)

    1962-02-15

    disposent probablement pas d'une quantite suffisante de thymidine dans le liquide ascitique. Les auteurs etudient la dichotomie entre la synthese du complement entier de l'ADN et la division subsequente de la cellule. (author) [Spanish] El tritio se utiliza en Israel como indicador para estudiar una gran variedad de problemas biologicos. Los autores describen en particular los resultados de unas investigaciones en que se ha utilizado timidina tritiada para estudiar la dinamica celular en la leucemia mieloide, inducida con lines experimentales, y analizar el mecanismo de la incorporacion de esa sustancia en el acido desoxirribonucleico de celulas leucemicas y de celulas de tumores asciticos de Ehrlich. Las celulas leucemicas se marcaron in vivo inyectando en la vena yugular de ratas timidina tritiada a razon de 1 {mu}curie/g de peso corporal. Se evaluo la velocidad de aparicion de las celulas marcadas en la sangre de la periferia y en el tumor ascitico de los animales. En otros experimentos se determino la velocidad de dilucion del indicador en los nucleos, lo que permitio calcular el tiempo de duplicacion de la poblacion de mielocitos. La dinamica de las celulas transfundidas se investigo inyectando mielocitos marcados en la vena yugular de ratas normales y leucemicas. Se midio su velocidad de desaparicion de la sangre. Se examinaron varios organos para ver si contenian celulas marcadas y se observo que poco despues de la inyeccion las celulas son principalmente captadas por los pulmones, despues por el bazo y, en menor grado, por el higado. Pasadas 24 h no se pudieron detectar celulas marcadas en ningun organo. De este modo, se obtuvo informacion sobre el comportamiento de los mielocitos leucemicos en distintos organos de animales normales y leucemicos. En experimentos realizados in vitro, se anadio a una suspension celular timidina tritiada en una concentracion de 1 {mu}curie/ml. Durante la marcacion in vitro se comprobo que el numero de celulas marcadas es 40 veces mayor

  13. Determinazione di ossidi di colesterolo in alici (Engraulis encrasicolus) trattate con una miscela commerciale di acido citrico, acido trisodico e perossido D'idrogeno

    OpenAIRE

    Raffaele, Marrone; Giorgio, Smaldone; Giuseppe, Palma; Raffaele, Romano; Domenico, Bortone; Aniello, Anastasio

    2012-01-01

    A new additive formulation containing hydrogen peroxide, citric acid and trisodium acid is illegally used in fishery products due its whitening and antioxidant features. Aim of this study was to evaluate the possible presence of COPs and their role as markers of illegal treatment in anchovies (Engraulis encrasicolus) stored at different temperatures. Sensory analysis was also performed by the specific QIM test. The quantitative determinations (%) of cholesterol oxides (COPs) showed changing a...

  14. Terpenes and fatty acids from Dipteryx lacunifera Ducke; Terpenos e acidos graxos de Dipteryx lacunifera Ducke

    Energy Technology Data Exchange (ETDEWEB)

    Vieira Junior, Gerardo Magela; Silva, Hilris Rocha e; Bittencourt, Thais Chaves; Chaves, Mariana H. [Universidade Federal do Piaui (UFPI), Teresina (Brazil). Dept. de Quimica]. E-mail: mariana@ufpi.br; Simone, Carlos Alberto de [Universidade Federal do Alagoas (UFAL), Maceio, AL (Brazil). Inst. de Quimica e Biotecnologia

    2007-07-01

    This paper describes the isolation of the furanocassane-type diterpene, named vinhaticoic acid, along with b-farnesene and spatulenol from fruit shells of D. lacunifera. Structural determinations were accomplished by chemical derivatization and spectral analysis, including 1D and 2D NMR and X-ray crystallography. The fatty portion was extracted from the fruit kernels, transesterfied and analysed by HRGC/MS. Oleic acid (75.8 +- 4.3%) was the major component. Essential oil extracted from the fruit shells of D. lacunifera was analysed by HRGC/MS and nine sesquiterpenes were identified; beta-farnesene (48.6%) and spatulenol (21.61%) were the major constituents. (author)

  15. Vitamina B12, Acido Fólico y Función Mental en Adultos Mayores

    OpenAIRE

    Meertens-R, Lesbia; Solano-R, Liseti

    2005-01-01

    Los adultos mayores constituyen un grupo de población vulnerable a cuadros de deficiencias de nutrientes específicos como la vitamina B12 y el ácido fólico, íntimamente ligados al deterioro de las funciones mentales, en especial, del área cognitiva. El objetivo de este estudio fue determinar indicadores del estado de vitamina B12 y ácido fólico y asociarlos a la evaluación de la función mental de 53 adultos mayores de 60 años de edad, residenciados en un hogar geriátrico. Se evaluó consumo di...

  16. Equilibrio de fases de sistemas compostos por oleos vegetais, acidos graxos e etanol hidratado.

    OpenAIRE

    Cintia Bernardo Gonçalves

    2004-01-01

    Resumo: Este trabalho de tese de doutoramento teve como objetivo avaliar vários aspectos do processo de extração líquido-líquido (ELL) como uma rota alternativa para a desacidificação de óleos vegetais. O conhecimento do equilíbrio de fases do sistema de interesse é essencial para o bom planejamento e desenvolvimento do processo de ELL. O presente trabalho apresenta dados de equilíbrio para sistemas compostos por óleos vegetais (milho/palma), ácidos graxos (oléico/ palmítico) e solvente (etan...

  17. Acid Deposition Maps in Spain; Mapas de Deposito Acido en Espana

    Energy Technology Data Exchange (ETDEWEB)

    Artinano, B; Cabal, H; Garcia, C

    1998-07-01

    Animal and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To do this, updated databases with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5x5 Km{sup 2} grid which allow to assess the methodology used in Europe to obtain the maps of excedances over the critical loads of pollutants. (Author) 32 refs.

  18. ELIMINACION DEL COLORANTE NEGRO ACIDO 194 DESDE AGUAS RESIDUALES TEXTILES MEDIANTE ELECTROCOAGULACION

    OpenAIRE

    VIDAL FUENTES, JORGE ARTURO

    2013-01-01

    Diariamente, las industrias textiles descargan grandes volúmenes de aguas que contienen altas concentraciones de colorantes y aditivos, los cuales ocasionan daños considerables al medio ambiente. Muchos de estos colorantes son estables a la luz y a la biodegradación, siendo considerados como compuestos orgánicos persistentes (COPs). Es por esto que es necesario aplicar métodos que permitan la eliminación de estos contaminantes desde las aguas. Una metodología efectiva para la eliminación de C...

  19. Changing electrolyte and acido-basic profile in HIV-infected patients in the HAART era.

    Science.gov (United States)

    Isnard Bagnis, Corinne; Du Montcel, Sophie Tezenas; Fonfrede, Michele; Jaudon, Marie Chantal; Thibault, Vincent; Carcelain, Guislaine; Valantin, Marc Antoine; Izzedine, Hassan; Servais, Aude; Katlama, Christine; Deray, Gilbert

    2006-01-01

    HIV-infected patients may develop a variety of underreported metabolic abnormalities that may be classified into HIVAN, specific HIV abnormalities, coincidental renal disorders and anti-retroviral-treatment-induced side effects. Our descriptive cross-sectional study evaluates the prevalence of electrolyte and acid base disorders in HIV patients in the HAART era in a tertiary care teaching hospital. All consecutive HIV-infected patients (n = 1,232) presenting at our Department of Infectious Disease over 3 months were included. All available biochemical data obtained at admission or on the day of the visit were analyzed. We identified risk factors for electrolyte and acid base disorders with univariate regression analysis and multivariate stepwise regression analysis. Variables tested for significance included age, sex, absolute CD4 and CD8 counts, hepatitis B and C antibodies, and use and type of anti-retroviral medication. Most frequent and clinically relevant abnormalities were hyperuricemia in 41.3%, hypophosphatemia in 17.2% and low bicarbonate level in 13.6% of HIV-tested patients. Plasma magnesium was out of the normal range in 38.9% and blood glucose in 25.3% of the tested patients. When CD4 count was below 200/mm3, 9.2% of tested patients experienced low serum calcium (vs. 0.5% if CD4 count >200/mm3, p 200/mm3, p 200/mm3, p < 0.0001). Protease inhibitor treatment was a significant risk factor of hyperuricemia (p < 0.003). Non-nucleoside reverse transcriptase inhibitor therapy was significantly associated with less hyperuricemia (OR = 0.6, 95% CI 0.38-0.96) and with hypophosphatemia (OR = 2.0, 95% CI 1.1-3.4). The profile of biochemical abnormalities in HIV-infected patients has changed, hyperuricemia and hypophosphatemia being the most prevalent. Causes are poorly understood. Interpretation of drug-induced side effects in the HIV patient is only meaningful if performed versus a control group of patients. Copyright 2006 S. Karger AG, Basel

  20. Cementation of wastes with boric acid; Cimentacao de rejeitos contendo acido borico

    Energy Technology Data Exchange (ETDEWEB)

    Tello, Cledola C.O.; Haucz, Maria Judite A. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil); Alves, Lilian J.L.; Oliveira, Arno H. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2000-07-01

    In nuclear power plants (PWR) are generated wastes, such as concentrate, which comes from the evaporation of liquid radioactive wastes, and spent resins. Both have boron in their composition. The cementation process is one of the options to solidify these wastes, but the boron has a negative effect on the setting of the cement mixture. In this paper are presented the experiments that are being carried out in order to overcome this problem and also to improve the efficiency of the process. Simulated wastes were cemented using additives (clays, admixtures etc.). In the process and product is being evaluated the effect of the amount, type and addition order of the materials. The mixtures were selected in accordance with their workability and incorporated waste. The solidified products are monolithic without free water with a good mechanical resistance. (author)

  1. Extração de acido carminico e analise por cromatografia liquida de alta eficiencia

    OpenAIRE

    Paulo Roberto Nogueira Carvalho

    1996-01-01

    Resumo: A preocupação dos consumidores com o uso de substâncias artificiais em alimentos tem aumentado muito nos últimos anos e feito com que os fabricantes procurem substitutos para os corantes artificiais ainda utilizados. O carmim de cochonilha, nome dado ao complexo de alumínio e cálcio do ácido carmínico (ácido 7- b - D - glicopiranosil - 9, 10 - diidro - 3, 5, 6, 8 - tetraidroxil - 1 - metil - 9, 10 - dioxo - 2 - antracenocarboxílico), extraído das fêmeas da cochonilha (Dactylopius cocc...

  2. Acidos grasos omega-3 en la nutrición ¿como aportarlos?

    OpenAIRE

    Valenzuela B, Alfonso; Valenzuela B, Rodrigo

    2014-01-01

    Los beneficios derivados del consumo de ácidos grasos omega-3 EPA y DHA de origen marino están sólidamente documentados, por lo cual existen recomendaciones para su consumo. La recomendación es consumir productos del mar, específicamente pescado. Sin embargo la disponibilidad de este recurso es cada vez menor. Los aceites marinos, ricos en ácidos grasos omega-3 son también cada vez más escasos y de mayor costo. El aceite de pescado, altamente inestable a la oxidación, se puede encapsular, mic...

  3. Acid Deposition Maps in Spain; Mapas de Deposito Acido en Espana

    Energy Technology Data Exchange (ETDEWEB)

    Artinano, B.; Cabal, H.; Garcia, C. [CIEMAT. Madrid (Spain)

    1998-12-31

    Annual and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To de this, updated database with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5 x 5 km``2 grid which allow to assess the methodology used in Europe to obtain the maps of excedance over the critical loads of pollutants. (Author) 32 refs.

  4. Estudo do comportamento acido-base de proteinas no sistema DMSO-Agua

    OpenAIRE

    Ivo Milton Raimundo Junior

    1989-01-01

    Resumo: Neste trabalho foi estudado o comportamento ácido-base da lisozima e ovalbumina no sistema DMSO-água (7,0: 0,8 ml) através de titulações termométrica catalítica (TTC) e potenciométrica. Na TTC foi utilizada acrilonitrila (4,0 ml) como indicador termométrico, sendo determinados 23,6±0,7 e 47,6±0,6 .grupos ácidos por moI de lisozima e ovalbumina, respectivamente. A comparação desses resultados com os obtidos por titulação potenciométrica das proteínas desnaturadas em uréia mostrou que o...

  5. Naphthenic acid characterization and distribution in crude oils; Caracterizacao e distribuicao de acidos naftenicos em petroleos

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Regina C.L.; Gomes, Alexandre de O. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Naphthenic acid corrosion was observed for the first time during the distillation process of some kind of crude oils in 1920. Recent reports about naphthenic acid corrosion have been found in China, India, Venezuela, Eastern Europe, Russia and the USA. In Brazil, heavy and acid crude oil processing is rising. Some brazilian crude oils have TAN around 3,0 mg KOH/g. The presence of relatively high levels of naphthenic acids in crude oils is a bane of petroleum refiners; and more recently, of producers as well, who have reported problems during production with calcium and sodium naphthenate . Essentially, these acids which are found to greater or lesser extent in virtually all crude oils are corrosive and tend to cause equipment failures, lead to high maintenance costs and may pose environmental disposal problems. In order to give these information to PETROBRAS, The Research and Development Center of PETROBRAS (CENPES) has been working in house and with brazilian universities developing analytical technicians to know better molecular structures and distribution of these acids compounds in crude oils. This work presents the actual methods and some results from these developments. (author)

  6. Prediction of neonatal metaboic acidos in women with a singleton term pregnancy in cephalic presentation

    NARCIS (Netherlands)

    Westerhuis, M.E.M.H.; Schuit, E.; Kwee, A.; Zuithoff, N.P.A.; Groenwold, R.H.H.; Akker, van den E.S.A.; Beek, van E.; Dessel, van H.J.H.M.; Drogtrop, A.P.; Geijn, van H.P.; Graziosi, G.C.M.; Lith, van J.M.M.; Nijhuis, J.G.; Oei, S.G.; Oosterbaan, H.P.; Porath, M.M.; Rijnders, R.J.P.; Schuitemaker, N.W.E.; Wijnberger, L.D.E.; Willekes, C.; Wouters, M.G.A.J.; Visser, G.H.A.; Mol, B.W.J.; Moons, K.G.M.

    2012-01-01

    We sought to predict neonatal metabolic acidosis at birth using antepartum obstetric characteristics (model 1) and additional characteristics available during labor (model 2). In 5667 laboring women from a multicenter randomized trial that had a high-risk singleton pregnancy in cephalic presentation

  7. Quantification of uranyl in presence of citric acid; Cuantificacion de uranilo en presencia de acido citrico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Barrera D, C.E. [UAEM, Facultad de Quimica, 50000 Toluca, Estado de Mexico (Mexico); Ordonez R, E. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: nidgg@yahoo.com.mx

    2007-07-01

    To determine the influence that has the organic matter of the soil on the uranyl sorption on some solids is necessary to have a detection technique and quantification of uranyl that it is reliable and sufficiently quick in the obtaining of results. For that in this work, it intends to carry out the uranyl quantification in presence of citric acid modifying the Fluorescence induced by UV-Vis radiation technique. Since the uranyl ion is very sensitive to the medium that contains it, (speciation, pH, ionic forces, etc.) it was necessary to develop an analysis technique that stands out the fluorescence of uranyl ion avoiding the out one that produce the organic acids. (Author)

  8. Isolation of deoxyribonucleic acids (A Review); Aislamiento de los acidos desoxiribonucleicos. Revision Bibliografica

    Energy Technology Data Exchange (ETDEWEB)

    Garcia de Pineda, M de

    1974-07-01

    The criteria of choice in this Review have been to gather some of the last advances in the methodology of DNAs isolation; also the description of the generally accepted procedures has been emphasized. Only papers published before March 1974 are reviewed, because this work has been finished during this month. (Author) 109 refs.

  9. Valutazione farmacoeconomica della prevenzione con picotamide vs acido acetilsalicilico dei pazienti diabetici con vasculopatia periferica

    Directory of Open Access Journals (Sweden)

    Sergio Iannazzo

    2005-12-01

    Full Text Available Type 2 diabetes mellitus (DM and peripheral arterial disease (PAD are two very relevant cardiovascular (CV risk factors, which can often be found concurrently in the same patient. The DAVID trial, a double-blind, randomized, aspirin(ASA-controlled study, has demonstrated that the use of picotamide, a thromboxane A2 synthase and receptor dual inhibitor, is associated with lesser CV morbidity and mortality in this type of patients in comparison to ASA, considered the standard antiplatelet agent. In order to estimate clinical and economic impacts of picotamide in the Italian health care setting, we developed a pharmacoeconomic model based on clinical data from DAVID and national economic parameters and demographics. The base case scenario, which reflects current prices and reimbursement policy (i.e. ASA fully paid for, picotamide out-of-pocket for patients yielded an incremental cost/effectiveness ratio (ICER of about 8,500 euro/year of life (YOL saved, which falls below conventionally adopted willingness to pay thresholds. This cost, however, is totally born by the patient, while the savings on health care expenditures for avoided events (and less ASA benefit the national health service (NHS. These results may help the physician in explaining the consequences of this choice to his/her patients, facilitating a fully-informed choice. The availability of a theoretical model allowed to explore some alternative scenarios, that indicate that the ICER can be further lowered and the economical burden better distributed through policy changes. In conclusion, the pharmacoeconomic model indicated that picotamide is likely to be a cost/effective option for CV mortality and morbidity prevention in patients with concurrent type 2 DM and PAD and that the level of adoption of this strategy will depend on willingness to pay and policy priorities of the NHS and patients themselves.

  10. Avaliacao da seguranca de diferentes doses de suplementos de acido folico em mulheres do Brasil

    Directory of Open Access Journals (Sweden)

    Quenia dos Santos

    2013-10-01

    Full Text Available OBJETIVO Avaliar a distribuição da ingestão de ácido fólico e a segurança de diferentes doses de suplementos em mulheres em idade reprodutiva. MÉTODOS Foram utilizados dados de consumo a partir de dois dias não consecutivos de registro alimentar de 6.837 mulheres em idade reprodutiva (19 a 40 anos participantes do Inquérito Nacional de Alimentação, módulo da Pesquisa de Orçamentos Familiares 2008-2009. Médias e percentis de consumo habitual de folato natural e ácido fólico foram estimados utilizando o método do National Cancer Institute . Cinco cenários foram simulados somando-se diferentes doses diárias de fortificação (400 mcg, 500 mcg, 600 mcg, 700 mcg e 800 mcg ao ácido fólico oriundo dos alimentos consumidos pelas mulheres. Comparou-se o total de ácido fólico (dieta + suplemento com o nível máximo de ingestão tolerável (UL = 1.000 mcg para definir a dose segura de suplementação. RESULTADOS Mulheres com ingestão habitual de ácido fólico acima do nível máximo de ingestão tolerável foram observadas para doses de suplemento de 800 mcg (7,0% das mulheres. Abaixo desse valor, qualquer dose de suplementação mostrou-se segura. CONCLUSÕES O uso de suplementos de até 700 mcg de ácido fólico mostrou-se seguro.

  11. Uranium accumulation in Brassica rapa L. and effect of citric acid and humic acids as chelating agents; Acumulacion de uranio en Brassica rapa L. y efecto del acido citrico y acidos humicos como agentes quelantes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez del R, H.; Perez C, G. A.; Davila R, J. I.; Mireles G, F. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Rodriguez H, G., E-mail: hlopezdelrio@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Agronomia, Carretera Zacatecas-Guadalajara Km 15.5, Cieneguillas, Zacatecas (Mexico)

    2016-09-15

    Phyto extraction is a technique that makes use of plants for the remediation of soils contaminated with heavy metals. In this study the uranium incorporation in the Brassica rapa L. species was evaluated, in artificially contaminated inert soils with 40 mg U/kg, and the effect of adding of the natural chelating agents citric acid and humic acids in the accumulation of uranium was analyzed. Soil free of organic matter and biologically inert was obtained by controlled calcination s of natural soil. Cultures in the prepared soil consisted of five growth treatments: 1) cultivation without uranium or additives; 2) cultivation in the uranium presence; 3) cultivation with uranium and citric acid (2 g/kg); 4) cultivation with uranium and humic acids (10 g/kg); 5) uranium cultivation and combination of citric and humic acids at the same concentrations. There was no adverse effect on plant growth with the presence of uranium at the given concentration. Regarding the controls, the total biomass in the presence of uranium was slightly higher, while the addition of humic acids significantly stimulated the production of biomass with respect to the citric acid. The combined action of organic acids produced the highest amount of biomass. The efficiency of phyto extraction followed the order Humic acids (301 μg U/g) > Non-assisted (224 μg U/g) >> Citric acid + Humic acids (68 μg U/g) > Citric acid (59 μg U/g). The values of uranium concentration in the total biomass show that the species Brassica rapa L. has the capacity of phyto extraction of uranium in contaminated soils. The addition of humic acids increases the uranium extraction while the addition of citric acid disadvantages it. (Author)

  12. Esterification from derivates of styrene by acetic acid using perchloric acid as a catalyzer; Esterificacion de derivados de estireno con acido acetico en presencia de acido perclorico como catalizador

    Energy Technology Data Exchange (ETDEWEB)

    Martinez de la Cuesta, P.J.; Rus Martinez, E.; Palomino sosa, R.; Palomino Perez, F. I. [Departamento deIngenieria Quimica, Facultad de Ciencias, Universidad de Malaga, Malaga (Spain)

    1995-11-01

    The present work is focused to develop the production of esters from derivatives of styrene by acetic acid using perchloric acid as a catalyst. The kinetics of the reaction was studied and analysis of the variables was carried out. 18 refs.

  13. Bacterias halotolerantes/alcalofilas productoras de acido indol acético (AIA asociadas a Arthrospira platensis (Cyanophyceae

    Directory of Open Access Journals (Sweden)

    Liliana Cecilia Gómez Gómez

    2012-07-01

    Full Text Available Título en ingles: Halotolerant alkalophilic and indolacetic acid producing acid producing bacteria associated with Arthrospira platensis (Cyanophyceae Resumen: Este trabajo tuvo como propósito contribuir al conocimiento de la interacción entre la cianobacteria alcalófila Arthrospira platensis y las bacterias que crecen asociadas a su mucilago. Se desarrolló un  medio de cultivo heterotrófico en el cual se aislaron cinco cepas bacterianas asociadas a un monocultivo de A. platensis. Se determinó la capacidad de estas cinco cepas para producir ácido 3- indol acético (AIA. La tipificación molecular de los aislamientos bacterianos permitió identificarlos como Exiguobacterium aurantiacum str. DSM 20416, Xanthomonas sp. ML-122, Halomonas sp. Ap-5, Bacillus okhensis str.  Kh10-101, Indibacter alkaliphilus, type str. LW1T; todas las cepas bacterianas obtenidas  son halotolerantes, alcalófilas y productoras de AIA. Los resultados aportan evidencia para sugerir una interacción benéfica entre A. platensis y sus bacterias asociadas,  quizá como estrategia evolutiva  de cooperación para desarrollarse en  un ambiente hipersalino.    Palabras claves: Bacillus okhensis, Exiguobacterium aurantiacum, Halomonas sp., Indibacter alkaliphilus. Xanthomonas sp. Abstract: The aim of this study was contribute to knowledge over alkalophilic cianobacteryum  Arthrospira platensis  and their  interaction with some associated bacteria growing in their mucilage. Heterotrophic culture medium was designed, in this medium were isolated five bacterial strains associated to single culture of A. platensis. It was measured the 3-indol acetic acid (IAA production by these bacterial strains. Molecular typing allowed identify these bacterial strains like Exiguobacterium aurantiacum str. DSM 20416, Xanthomonas sp. ML-122, Halomonas sp. Ap-5, Bacillus okhensis str. Kh10-101, Indibacter alkaliphilus, type str. LW1T; all these bacteria are halotolerant, alkalophilic and IAA producer.  The findings allow suggest a beneficial interaction between A. platensis and their associated bacteria, maybe as evolutionary strategy of cooperation to grow and develop in  hypersaline environments. Key words: Bacillus okhensis, Exiguobacterium aurantiacum, Halomonas sp., Indibacter alkaliphilus.Xanthomonas sp.

  14. Homocisteína, acido fólico y vitamina B12 en adultos mayores venezolanos

    OpenAIRE

    Meertens G, Lesbia; Díaz W, Nayka; Solano R, Liseti; Baron, Maria Adela; Rodríguez M, Adelmo

    2007-01-01

    Los cambios anatomo-fisiológicos propios del envejecimiento hacen de los adultos mayores un grupo vulnerable a los estados de malnutrición y deficiencias específicas de nutrientes como la vitamina B12 y el folato. El objetivo de este estudio fue establecer la relación existente entre la vitamina B12, folato, homocisteína y el consumo y adecuación de estos nutrientes. Se evaluaron 55 adultos mayores de 60 años de edad, de ambos sexos, no institucionalizados, a quienes se les determinó homocist...

  15. Gas chromatography of alkylphosphonic and dialkyl phosphinic acids; Cromatografia en fase gaseosa de acidos alquifosfonicos y dialquilfosinicos

    Energy Technology Data Exchange (ETDEWEB)

    Gasco Sanchez, L; Barrera Peniero, R; Ramirez Caceres, A; Marin Munoz, M

    1978-07-01

    After carrying out an optimization study on the separation conditions for the TMSr- derivatives, of the hexyl-, cyclohexyl-, heptyl-, and octyl-phosphonic acids; dihexyl dicyclohexyl-, heptyl-, and octyl-phosphinic acids, and dioctyl phosphine oxide, their retention indices (I) at two temperatures and on the OV-1 and OV-17 stationary phase were determined. Correlations between I and molecular structure were established. Calibration factors of these compounds in the flame ionization detector were studied, and the results analyzed taking into account the variables affecting the quantitative results, These results were unbiased but they had a lower precision than that usually achievable in gas chromatography. (Author) 24 refs.

  16. Analise dos meios de cultura para a produção de acido citrico por linhares de Aspergillus niger

    OpenAIRE

    Liliana Agudelo Acosta

    1994-01-01

    Resumo: Foi acompanhado o comportamento de vinte linhagens de Aspergillus niger na produção de ácido cítrico, quando cultivadas em diferentes formas e meios de fermentação. Observou-se que as exigências nutricionais de Aspergillus niger para a produção de ácido cítrico dependem da linhagem e do processo do cultivo. Dentre as linhagens estudadas e nas condições experimentais - fermentação em superfície e submersa em meio natural, escolheram-se as cepas FTPT 906 para a fermentação em superfície...

  17. Alternative disinfectant in drinking water systems. The peracetic acid; Disinfettanti alternativi in potabilizzazione. L`acido peracetico

    Energy Technology Data Exchange (ETDEWEB)

    Ragazzo, Patrizia; Navazio, Giancarlo [Padua, Univ. (Italy). Fac. di Ingegneria. Dipt. dei Processi Chimici dell`Ingegneria; Cavadore, Alberto [Solvay Interox, Rosignano (Italy); Babato, Ferdinando [Consorzio per l`Acquedotto del Basso Piave, S. Dona` di Piave (Italy)

    1997-03-01

    The need to use oxidation techniques in mains water systems, especially when treating surface water, has brought about a greater awareness as to the health risks associated to the presence of residual chemical compounds or disinfection by-products (DBP), which are commonly found in water supplies treated by means of traditional disinfectants (i.e. Cl{sub 2}, ClO{sub 2}, NH{sub 2}Cl, O{sub 3}, etc.). As a consequence, legislative standards have had to define greater restrictions regarding their use. In the light of this situation, the authors have set out to examine the feasibility of employing peracetic acid (PAA), which features low production of DBPs, as an alternative disinfectant. Preliminary experimental tests have been carried out on water samples taken from several process points within a water treatment plant at the Basso Piave mains water system, located in Jesolo, near Venice in Italy. These samples were treated with batch PAA doses ranging from 1 to 5 ppm for a variety of different exposition periods, also with varying temperature, pH and water properties. These experiments made it possible to asses the decay kinetics of PAA as well as reduction of characteristic microbiological parameters in raw and treated incoming and outgoing water throughout the various stages of the treatment process. The results achieved during these tests appear to provide ample evidence regarding the possibilities of use for PAA (with medium dosage of 1.5 to 2 ppm, contact times from 30` to 60` and abatement up to 95 %), after having assessed its compatibility, especially in order to the increase of the assimilable organic carbon, with the characteristics of the plant and distribution network, by continuous reactors and pilot plants.

  18. New heterogeneous acid catalysts in the synthesis of biodiesel; Estudo de novos catalisadores heterogeneous acidos na sintese de biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Soldi, Rafael A.; Cesar-Oliveira, Maria Aparecida F. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica. Lab. de Polimeros Sinteticos], e-mail: mafco@quimica.ufpr.br; Oliveira, Angelo R.S.; Ramos, Luiz P. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica. Centro de Pesquisa em Quimica Aplicada (CEPESQ)

    2007-07-01

    In this work, sulfonated polystyrene compounds (PSS) were synthesized from linear polystyrene (PS). Several methods and experimental conditions were investigated for the sulfonation of PS, producing catalytically active polymeric materials with sulfonation degrees in the range of 5.0-6.2 mmol -SO{sub 3}H/g of dry polymer. The performance of these catalysts was evaluated in transesterification reactions of beef tallow and vegetable oils with ethanol and methanol. For the sake of comparison, the same reaction conditions employed for the PSS catalysts were also used for an Amberlyst 15 (3,7 mmol SO{sub 3}H/g - Aldrich). The PSS samples were shown to be insoluble in the reaction media, leading to conversion rates of 85%, 75% and 80% of the refined soybean oil, beef tallow and crude corn oil in to ethyl esters, respectively, and 94% of the refined soybean oil methyl esters. Amberlyst 15 was studied as an alternative to the process, but its conversion rate to alkyl esters was very low in the employed conditions. These results demonstrated that our synthetic PSS materials have a great potential to act as heterogeneous catalysts for transesterification. (author)

  19. Oxidos de colesterol, colesterol, lipidios totais e composição de acidos graxos em carne de peru

    OpenAIRE

    Sueli Regina Baggio

    2000-01-01

    Resumo: Considerando que o colesterol é um esterol largamente distribuído no reino animal, susceptível à oxidação quando exposto ao ar, a temperaturas elevadas, luz, radiação ou à combinação destes fatores, pode ocorrer a formação de vários produtos de oxidação, tais como: 25-hidroxicolesterol; colestan-3 beta-5alfa-6 beta-triol; 5,6alfa-epoxicolesterol; 5,6 beta-epoxicolesterol; 7alfa-hidroxicolesterol; 7 beta-hidroxicolesterol; 7-cetocolesterol e colesta-4,6-dien-3-ona. Estes compostos são ...

  20. Immobilization of citric acid solutions in portland cement; Imobilizacao de solucoes de acido citrico em cimento Portland

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Valdir M.; Rzyski, Barbara M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1997-12-01

    Decontamination processes by using citric acid on certain items used in the nuclear area, can result in large volumes of liquid wastes with low activity or effluents, contaminated with uranium and some elements dangerous to the environment. A great number of installations that have decontamination processes adopt the zero discharge philosophy. So, one of the forms to isolate the solutions is by reducing its volume through the evaporation process. The generated must can be neutralized and encapsulated or immobilized in Portland cement. This work propose a chemical technique to destroy the citric acid in the decontamination solutions instead of neutralization and, depending on the installation convenience, a direct cement immobilization of these solutions or of the evaporation mud. The results obtained in this work involve data about the workability, setting time and mechanical resistance, after 28 days of sealed cure, for samples with water-cement ratios of 4, 0.5 and 0.6, by weight. (author). 5 refs., 2 tabs.

  1. Carboxymethylcellulose hydrogel crosslinked with citric acid for biomedical application; Reticulacao de hidrogeis de carboximetilcelulose com acido citrico para aplicacoes biomedicas

    Energy Technology Data Exchange (ETDEWEB)

    Capanema, Nadia S.V.; Mansur, Alexandra A.P.; Mansur, Herman S., E-mail: nsvnadia@gmail.com [Centro de Nanociencias, Nanotecnologia e Inovacao (CeNano), MG (Brazil); Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Metalurgica e Materiais

    2016-07-01

    The carboxymethylcellulose (CMCel) has been extensively used in order application as flexible polymer membrane. Biopolymers crosslinked have been studied to optimize their performance in biomedical applications. In this work, CMCel films with a degree of substitution (DS = 0.77) were prepared by evaporation of solvent and crosslinked with different concentrations of citric acid (CA). The synthesized CMCel was characterized by Infrared Spectroscopy by Fourier Transform X-ray spectroscopy (FTIR), and morphology assessed by scanning electron microscopy (SEM). Morphological analysis performed using the SEM indicated the crosslinked CMCel and not crosslinked with a very smooth and uniform appearance. The FTIR results indicated the modification of existing bands and appearance of a new band 1715 cm{sup -1} suggesting that there has been change in the structure of the crosslinked CMCel. (author)

  2. Producción de acido láctico por Lactobacillus plantarum L10 en cultivos batch y continuo

    Directory of Open Access Journals (Sweden)

    Waldir Estela

    2013-04-01

    Full Text Available Se ha ensayado a escala de laboratorio la cepa Lactobacillus plantarum L10, para la producción de ácido láctico en cultivos batch y continuo; además se ha optimizado la composición del medio y las condiciones de cultivo para este propósito. Los mejores parámetros de producción de ácido láctico encontrados en cultivo batch fueron los siguientes: YP/S 86,1%; PP 5,4 g/L/h; unido a YX/S 13,2%; PX 1,2 g/L/h y μ = 0,2 h-1, el cultivo se ha llevado a cabo en un medio conteniendo glucosa 70 g/L; extracto de levadura 12,1 g/L; KH2PO4 1,2 g/L; (NH42HPO4 1,2 g/L; citrato de amonio 3,0 g/L; MgSO4. 7H2O 0,3 g/L y MnSO4. 4H2O 0,03 g/L. Así mismo los mejores parámetros de producción de ácido láctico encontrados en cultivo continuo fueron los siguientes: YP/S 96%; P´P 6,0 g/L/h; unido a YX/S 19 %; P´X 1,2 g/L/h; y tasa de dilución (D 0,46 h-1.

  3. Revisión de los niveles de acidos grasos trans encontrados en distintos tipos de alimentos

    Directory of Open Access Journals (Sweden)

    Vicario, I. M.

    2007-03-01

    Full Text Available In this paper a comprehensive review of trans-fatty acid levels reported in different types of food products is offered. The lowest levels are found in some types of bread (0,1% while the highest levels (up to 40% are found in fried potatoes. Some foods like shortenings, cakes and pastries may have up to 30% of these fatty acids. In milk and dairy products the reported levels are between 1.50% and 5.20%, in meat and derived products between 0.20% and 21,30%; in chocolates from 0% to 15, 70%. The greatest variability is found in margarines, where a variety has been reported from “trans-free products” to products containing up to 34. 30%. In relation to the trans-fatty acid profile, 18:1t is the most abundant fatty acid found in the majority of foods, followed by C18:2t, C18:3t, C18:1t y C14:1t. Due to the negative health effects of these fatty acids, there is a trend to reduce their levels in food products and to include them in the nutritional label of food packaging.En este trabajo se realiza una exhaustiva revisión bibliográfica de los contenidos en grasos trans en alimentos de distinto origen. Los niveles más bajos se encuentran en algunos tipos de pan (0,10%, y los más elevados (hasta 40%, en algunas muestras de patatas fritas. Alimentos tales como shortenings, algunos tipos de galletas y bollería contienen hasta el 30% de dichos ácidos grasos. En las leches y derivados se encuentran cantidades entre 1,50% y 5,20%; en carnes y derivados entre 0,20% y 21,30%; en chocolates desde cantidades nulas hasta 15,70%. La mayor variabilidad se registra en margarinas, entre las que se encuentran desde las “libres de trans”, hasta algunas con 34,30% de estos ácidos grasos. En cuanto a los distintos isómeros, el mayoritario es el C18:1t seguido del C18:2t, C18:3t, C18:1t y C14:1t. Debido a los efectos desfavorables que presentan sobre la salud se observa en los últimos años una tendencia a reducir este tipo de ácidos grasos en algunos alimentos y a incluirlos en el etiquetado nutricional de los alimentos.

  4. Volatile fatty acid degradation kinetics in anaerobic process; Cinetica de la degradacion de acidos grasos volatiles en procesos anaerobios

    Energy Technology Data Exchange (ETDEWEB)

    Riscado, S.; Osuna, B.; Iza, J.; Ruiz, E. [Universidad del Pais Vasco. Bilbao (Spain)

    1998-10-01

    While searching for the optimal substrate load for anaerobic toxicity assays, the inhibition caused by the propionic acid has been addressed. Lab scale experiments have been carried out to assess the effects of different loads and acid ratios. Results bad been subjected to kinetic analysis and show the degradation follows a first order kinetic, and acetic is easier to degrade than propionic acid. The optimal load for a 100 ml vial assay is composed of 158 mg COD of the 3:1:1 HAc:HPr:HBu mixture. (Author) 9 refs.

  5. Determinación espectrofluorimétrica de fitohormonas derivadas del indol y del naftaleno

    OpenAIRE

    Blanc García, María del Rosario

    2014-01-01

    Se realiza el estudio de las propiedades fluorescentes y la puesta a punto de metodología espectrofluorimétrica en disolución y en fase sólida para la determinación en aguas, suelos y formulaciones comerciales de las fitohormonas derivadas del indol: acido indol-3-acetico. acido indol-3-butirico, acido indol-3-propinoico y acido 5-hidroxiindol-3-acetico; y del naftaleno: acido 1-naftilacetico y 1-naftilacetamida. se lleva a cabo la determinación individual de cada una de las fitohormonas as...

  6. Analytical methods for 2,4-D (Dichlorophenoxyacetic acid) determination; Metodos analiticos para la determinacion del 2,4-D (Acido diclorofenoxiacetico)

    Energy Technology Data Exchange (ETDEWEB)

    Martinez G, M.S.M

    1999-06-01

    The 2,4-D herbicide is one of the main pesticides for controlling the bad grass in crops such as the water undergrowth. In Mexico the allowed bound of this pesticide is 0.05 mg/l in water of 2,4-D so it is required to have methods trusts and exacts, which can used in order to detected low concentration of it. In this work we show some for the conventional techniques and for establishing the 2,4-D concentrations. The UV-Vis spectrometer and liquids chromatography due that they are the most common used nowadays. Beside, we introduce a now developed technique, which is based on the neutronic activation analysis. Though use of the UV-Vis spectrometer technique it was possible target the concentrations interval between 1 and 200 mg/l. In the liquids chromatography interval was between 0.1 and 0.9, and by the neutronic activation analysis the interval was between 0.01 and 200 mg/l. (Author)

  7. Basicity determination for neutral phosphorus organic extragents by NMR 31P-method in two-phase systems, and quantitative interrelations of acido-basic extractive properties

    International Nuclear Information System (INIS)

    Laskorin, B.N.; Yakshin, V.V.; Meshcheryakov, N.M.; Yagodin, V.G.

    1988-01-01

    Consideration is given to the method for determination of basicity of neutral organophosphorus compounds of XGZP=0 type (X, G, Z=C 4 H 9 , C 8 H 17 , C 6 H 5 ). The method is based on change of chemical shift of phosphorus-31 nuclei in two-phase extraction system depending on acidity function H O , H A , H PO . It is shown that the method can be used for evaluation and forecasting of phosphine oxide ability in the processes of UO 2 SO 4 solvent extraction from aqueous solutions of sulfuric acid

  8. Myrsinoic A acid and its derivative: in vitro inhibitors of photosynthesis; Acido myrsinoico A e derivado: inibidores da fotossintese in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Marcela Carmen de M.; Oliveira, Gracielle S. de; Menezes, Antonio Carlos S [Universidade Estadual de Goias, Anapolis, GO (Brazil). Unidade Universitaria de Ciencias Exatas e Tecnologicas; Vieira, Paulo Cezar; Silva, Maria Fatima das G.F. da [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Dept. de Quimica; Veiga, Thiago A.M., E-mail: tveiga@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Inst. de Ciencias Ambientais, Quimicas e Farmaceuticas. Dept. de Ciencias Exatas e da Terra

    2012-07-01

    Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methyl viologen; therefore, they act as Hill reaction inhibitors in spinach thylakoids. They inhibited partial reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P{sub 680} and Q{sub A}. Chlorophyll {alpha} fluorescence measurements confirmed the behavior of the compounds (pool of quinones). (author)

  9. Kraft pulp bleaching with molybdenum activated acid peroxide (P{sub Mo} stage); Branqueamento de polpa celulosica kraft de eucalipto com peroxido acido ativado por molibdenio

    Energy Technology Data Exchange (ETDEWEB)

    Rabelo, Marcos Sousa [Servico Nacional de Aprendizagem Industrial (SENAI), Lauro de Freitas, BA (Brazil). Dept. Regional da Bahia; Silva, Vanessa Lopes; Barros, Denise Pires de; Colodette, Jorge Luiz [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Engenharia Florestal; Sacon, Vera Maria; Silva, Marcelo Rodrigues da [Votorantim Celulose e Papel, Jacarei, SP (Brazil)

    2009-07-01

    Optimum conditions to run the P{sub Mo} stage for bleaching eucalyptus kraft pulp were 90 deg C, pH 3.5, 2 h, 0.1 kg/t Mo and 5 kg/t H{sub 2}O{sub 2}. The P{sub Mo} stage efficiency increased with decreasing pH (1.5-5.5) and increasing temperature (75-90 deg C), time (2-4 h), and hydrogen peroxide (3-10 kg/t) and molybdenum concentration (0.1-0.4 kg/t). The implementation of the P{sub Mo} stage, as replacement for the A stage, decreased total active chlorine demand of the OAZDP sequence by 6 kg/t to reach 90% ISO, both in laboratory and mill scale. Such practice resulted in decreased bleaching chemical costs to produce fully bleached pulp of 90% ISO. (author)

  10. DESARROLLO Y OPTIMIZACION TECNOLOGICA DE ACEITES MARINOS PARA INCREMENTAR EL.e-CONTENIDO DE ACIDOS GRASOS OMEGA 3 DE CADENA LARGA EN CARNES DE A VES Y CERDOS

    OpenAIRE

    Bórquez Lagos, Fernando

    2013-01-01

    • Origen (problema que resuelve u oportunidad que aprovecha)Investigaciones desarrolladas en los últimos años han permitido conocer la función y efecto que tienen los ácidos grasos poli-insaturados de cadena larga (AGPICL) omega 3, particularmente el Ácido Eicosapentaenoico (EPA) y el Ácido Docohexaenoico (DHA), en la prevención de enfemedades cardiovasculares, en el desarrollo del tejido nervioso, del órgano de la visión, de mecanismos que mejoran la inmunidad, etc. Su consumo esta aso...

  11. Spectrophotometric determination of titanium with ascorbic acid in aluminium alloys and other materials. Determinacion espectrofotometrica de titanio con acido ascorbico en aleaciones de base aluminio y otros materiales

    Energy Technology Data Exchange (ETDEWEB)

    Bosch Serrat, F. (Departamento de Quimica Analitica. Facultad de Qauimica. Valencia (Spain))

    1994-01-01

    A spectrophotometric determination of titanium with ascorbic acid in aluminium alloys and bauxite is described. The proposed procedures permit to determine levels of titanium down to 5.10 ''3% with a good accuracy and precision. (Author) 13 refs.

  12. Natural Radiation in byproducts of the production of phosphoric acid; Radiacao natural em residuos gerados no processo de producao de acido fosforico

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Marcilei A. Guazzelli da; Cardoso, L.L., E-mail: marcilei@fei.edu.br [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil); Medina, N.H. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Institutlo de Fisica

    2014-07-01

    Natural radiation is the largest source of radiation exposure to which man is subject. It is formed basically by cosmic radiation and the radionuclides present in the Earth crust, as {sup 40}K and the elements of the decay series of {sup 232}Th and {sup 238}U. Phosphate ores, which constitutes the raw material for the production of phosphoric acid, have a high rate of natural radiation from the decay series of {sup 232}Th and {sup 238}U. Phosphogypsum, which is naturally radioactivity, is a by-product of the production of phosphoric acid by the wet method. For each ton of phosphoric acid it is produced about 4.5 tons of phosphogypsum. This work presents the analysis of samples collected in all stages of the manufacturing process of phosphoric acid, which generates the phosphogypsum. Gamma-ray spectrometry was used to measure the concentration of the elements of the decay series of {sup 232}Th and {sup 238}U. All analyzed samples showed a high concentration of radionuclides, promoting the need for further steps in the process in order to reduce the presence of such radionuclides in the phosphogypsum. The results indicate the radionuclide {sup 238}U has higher contribution in some samples of the intermediate stages of the process. All samples exceeded the international average range of human exposure to terrestrial gamma radiation, which is 0.3 to 1.0 mSv/year. (author)

  13. Effect of the temperature and oxalic acid in the uranyl sorption in zircon; Efecto de la temperatura y acido oxalico en la sorcion de uranilo en circon

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Almazan T, M. G.; Garcia G, N. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Hernandez O, R., E-mail: eduardo.ordonez@inin.gob.mx [Instituto Tecnologico de Veracruz, Ingenieria Quimica, Miguel Angel de Quevedo No. 2779, 91860 Veracruz (Mexico)

    2012-10-15

    In this work the results of the temperature effect study are presented on uranyl solutions adsorbed on zirconium silicate (ZrSiO{sub 4}) and also on the compounds formed in surface with oxalic acid. The adsorption isotherms of uranyl on hydrated zircon with NaClO{sub 4} 0.5 M, show an increase of the uranyl sorption efficiency when increasing the temperature from 20 to 4 C with a sudden descent in this efficiency when changing the temperature at 60 C. The uranyl sorption efficiency increases to hydrate the zircon with a solution of oxalic acid 0.1 M, maintaining the same tendency regarding to the temperatures of the sorption in medium NaClO{sub 4} 0.5 M. The complex formation in the zircon surface with organic acids of low molecular weight increases the fixation of the uranyl in solution due to the formation of ternary systems, in the order Zircon/A. Organic/Uranyl, without altering their response to the temperature. (Author)

  14. Description and implementation of acid/base titrimetric techniques for process monitoring; Descripcion e implementacion de tecnicas titrimetricas acido/base para la monitorizacion de procesos

    Energy Technology Data Exchange (ETDEWEB)

    Marcelino Represa, M.; Guisasola i Canudas, A.; Casa Alvero, C.; Lafuente Sancho, F. J.

    2006-07-01

    The basis of titrimetric techniques is that the proton production (or consumption) rate can be indirectly measured with the amount of base (or acid) dosage necessary to maintain the pH at a certain setpoint value. Titrimetric measurements are very useful for the monitoring of any process that influences pH with simple equipment (an accurate pH control loop). This work describes the theoretical basis of titrimetric measurements and shows three examples of the application of titrimetric techniques for the process monitoring: CO{sub 2} absorption, nitrification and biological organic matter removal. (Author)

  15. Behaviour of the 1-Ascorbic as supporting Electrolyte. Influence of the Magnesium Ion; Comportamiento del acido 1-Ascorbico como electrolito soporte influencai del ion magnesio

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Lopez, J

    1962-07-01

    The behaviour of 1-ascorbic acid, as supporting electrolyte of the uranyl ion in a 0{sub 1}-0.7 M concentration range, and the influence of pH on the diffusion current and half wave potential of 0,1 M uranyl ion is studied. The cathodic waves from 0 to -2,5 volts, with mercury dropping electrode are studied in fresh 0,1 M aqueous solution in presence of Mg{sup 2}+ and at 2,0-12 pH range. A kinetic current with a half wave potential of 0,85 v. vs. Hg. b.e. is obtained at pH> 9,5 appears a tilth wave a -0,60 v. The pH variation does not influence these potentials. (Author) 18 refs.

  16. Obtención de Acido Poli Láctico a partir de lactosuero para la fabricación de empaque primarios.

    OpenAIRE

    Cuichán Guanoluisa, Remigio Ismael

    2015-01-01

    En la Provincia de Chimborazo, Cantón Riobamba, se evaluó la obtención de ácido poliláctico (APL), a partir de lactosuero para la fabricación de empaques primarios, teniendo un total de 16 unidades experimentales, distribuidas en 4 tratamientos (4 niveles de plastificante 1.5, 2.0, 2.5 y 3.0 %) y 4 repeticiones en cada uno. Los resultados experimentales fueron analizados mediante el análisis de varianza y la separación de medias con la prueba de Tuckey, con la finalidad de dete...

  17. DETERMINACIÓN DE RESIDUOS DE GLIFOSATO Y DE SU METABOLITO ACIDO AMINOMETILFOSFONICO EN AGUAS MEDIANTE CROMATOGRAFIA LIQUIDA DE ALTA EFICIENCIA CON DERIVACION POSCOLUMNA Y DETECCION POR FLUORESCENCIA

    Directory of Open Access Journals (Sweden)

    Hugo A Rodríguez

    2010-11-01

    Full Text Available El glifosato es un herbicida no selectivo,ampliamente utilizado en el mundo para controlar malezas anuales y perennes. Su principal metabolito en suelos y aguas es el ácido aminometilfosfónico (AMPA formado por la acción de microorganismos. Este herbicida se utiliza en Colombia en altas dosis para la erradicación de cultivos ilícitos de coca y amapola, y como madurante en caña de azúcar, constituyendo un problema ambiental y social en el país, y haciéndose necesaria la evaluación de residuos de glifosato y su metabolito en diferentes matrices. En este trabajo se validó una metodología analítica para determinar residuos de glifosato y de su metabolito AMPA en aguas de influencia de algunas regiones colombianas. El procedimiento experimental comprende dos pasos principales: el primero es un paso de limpieza, extracción y concentración en fase sólida; el Segundo corresponde a la separación, identificación y cuantificación de los compuestos mediante Cromatografía Líquida de Alta Eficiencia (CLAE con derivación poscolumna y detección por fluorescencia. Los resultados de la validación muestran que la metodología es específica, selectiva, precisa y robusta en un rango lineal entre 10 y 750 /xg/L, con límites de detección de 0,8 /xg/L y límites de cuantificación de 2 /ig/L para los dos analitos. Las recuperaciones se encuentran en el orden del 73% para glifosato y del 70% para el AMPA. Además, se muestran los resultados de análisis de aguas tomadas en algunas zonas del país donde se aplica glifosato en diferentes dosis con diferentes propósitos, encontrándose residuos del herbicida y de su metabolito en concentraciones por encima de los valores permitidos en aguas potables para plaguicidas de categoría toxicológica IV, caso del glifosato, de acuerdo con la legislación colombiana

  18. Comparative experimental study on municipal wastewater disinfection with ozone and peracetic acid; Indagine sperimentale comparata sulla disinfezione di acque reflue urbane con ozono e acido peracetico

    Energy Technology Data Exchange (ETDEWEB)

    Andreottola, G.; Bertola, P.; Ziglio, G. [Trento Univ. (Italy). Dip. di Ingegneria Civile Ambientale

    1996-04-01

    The results of a pilot experimental study on the disinfection of treated municipal wastewater to be used in agriculture are presented. A comparative evaluation has been carried out on two parallel pilot-scale disinfection plants using respectively ozone and peracetic acid. After a preliminary sand filtration pilot unit. Both processes showed the capability of meeting the Italian standards for agricultural reuse, but the disinfection process with ozone required much higher doses than the one with peracetic acid, probably because of the higher reactivity of ozone, if compared to peracetic acid with the organic matter present in wastewater. Further research is needed in order to evaluate the efficiency of peracetic acid applied to microorganism different from the bacterial ones and to identify nature and consequences of possible disinfection by products.

  19. PROPAGACIÓN VEGETATIVA DE PLÁTANO Y BANANO CON LA APLICACIÓN DE BENZILAMINOPURINA (6-BAP) Y ACIDO INDOLACETICO (AIA)

    OpenAIRE

    Hayron Fabricio Canchignia Martínez; Gonzalo Rafael Benavides Velasquez; Marjorie Dolores Espinoza Roca; Mercedes Susana Carranza Patiño; Orly Fernando Cevallos Falquez; Silvia Gicela Saucedo Aguiar

    2008-01-01

    En la propagación vegetativa de dos variedades de Banano (Valery y Orito) y una de Plátano (Barraganete), se sometió a diferentes tratamientos hormonales, para evaluar el número de brotes, la concentración 30 mg L-1 de BAP alcanzó el mayor promedio, con 2.36 brotes para todas las variedades. En longitud y diámetro de brotes, la concentración que logró el mayor promedio fue C0, no encontrándose diferencias entre las concentraciones de 6-BAP y AIA. La variedad que presentó la mayor longitud y d...

  20. Evaluation of ultrasonic technique to characterize the concentration of boric acid in liquid medium; Avaliacao de tecnica ultrassonica para medida de concentracao de acido borico em meio liquido

    Energy Technology Data Exchange (ETDEWEB)

    Kohara, Richard Yuzo Ramida

    2015-06-01

    This dissertation is to analyze the viability of using ultrasonic technique to characterize the concentration of boric acid in liquid medium non-invasively, therefore, ultrasonic tests were performed relating different boric acid concentrations with the travel time of the ultrasonic wave, also were evaluated factors able to mask the characterization of these concentrations by ultrasonic technique. The results showed that the ultrasonic technique allows the characterization of boric acid concentrations in liquid medium in very simple terms by the ultrasonic wave travel time, requiring further studies in complex conditions. (author)

  1. Efeito do acido borico sobre a reação de formação da oxima da benzoina

    OpenAIRE

    Dal Magro, Jacir

    1993-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciencias Fisicas e Matematicas A reação entre a hidroxilamina e benzoína ocorre em duas etapas: formação de um intermediário de adição e a desidratação deste à oxima. A reação na presença de ácido bórico (0,01M) a pH 8,5 apresenta um aumento no valor de kobs em até l5 vezes. Este valor é maior na presença de ácido fenil bórico, onde a diferença atinge 28 vezes. Tampões que possuem pKas semelhantes não apresentam ne...

  2. Radiological assessment occupational radionuclides in a phosphoric acid plant; Evaluacion radiologica ocupacional y distribucion de radionucleidos en una planta de acido fosforico

    Energy Technology Data Exchange (ETDEWEB)

    Bolivar, J. P.; Garcia-Tenorio, R.

    2008-07-01

    On the frame of a research project devoted to the control of the exposure due to natural radiation in several NORM industries located at the South of Spain, a detailed to the production of phosphoric acid has been performed. In addition, the behaviour along the mentioned process of the different radionuclides involved has been analysed. It has been concluded that the effective dose which can be received by the workers of the plant is clearly below 1 mSv/year. And it has been demonstrated that the main route of occupational exposure corresponds to the external radiation due mainly to the permanent presence of a radioactive contamination source in different zones of the plant. This contamination source is associated to the presence of scales in the inner surfaces of pipes and equipment as well as to the presence of sludges in the phosphoric acid storage tanks, which in both cases contain elevated concentrations of 226{sup R}a. Moreover, the 222{sup R}n concentrations inside the plant do not overpass 100 Bq/m{sup 3}, which not constitutes a radiological problem. (Author) 9 refs.

  3. Electrorremediación de suelos arenosos contaminados por Pb, Cd y As provenientes de residuos mineros, utilizando agua y acido acético como electrolitos

    OpenAIRE

    García Hernández, Laura; Vargas Ramírez, Marissa; Reyes Cruz, Víctor

    2011-01-01

    En el presente trabajo se realizaron estudios potenciostáticos en una celda de electrorremediación experimental, de un suelo real tipo arenoso (93% arena) contaminado por la oxidación residuos mineros proveniente de la zona de Zimapán Hidalgo, se utilizó agua desionizada, CH3COOH y CH3COONH4 0.001 M, ya sea como humectante del suelo o como electrolitos, se aplicó un potencial constante de 20 V durante 24 horas. Al terminar los experimentos se recuperó el suelo, se determinó el pH, observándos...

  4. The dynamics of acetic acid in the anaerobic treatment of abattoir sewage; Dinamica del acido acetico en la depuracion anaerobia de aguas residuales de mataderos

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Borges, E.; Acosta Viana, K. [Universidad Autonoma de Yucatan. Mexico (Mexico)

    1999-05-01

    The purpose of this experiment was to examine the production and consumption of acetic acid during the anaerobic treatment of sewage from a municipal abattoir. The experiment studied a 20-litre UASB reactor under three hydraulic retention time (HRT) conditions-4 days, 2.5 days and 1.6 days-measuring the acetic acid concentration in the reactor in fluent and effluent. The results obtained during the experiment with the three different HRTs are reported. The highest percentages of acetic acid removed ( an average of 44%) were obtained with an HRT of 4 days. The amount of acetic acid removed with and HRT of 2.5 days was 27%. (Author) 18 refs.

  5. Study of the interaction of enzyme Heparanase 1 (HPSE1) active with deoxyribonucleic acids; Estudo de interacao da enzima Heparanase 1 (HPSE 1) ativa com acido desoxirribonucleicos

    Energy Technology Data Exchange (ETDEWEB)

    Cid, Gisele da Silva

    2016-07-01

    The human heparanase 1 (HPSE 1) is a protein with multiple functions and has emerged as a promising therapeutic target in the context of antitumor therapy. This fact is due to its clinical relevance in the tumor development and progression, as determined by their enzymatic ability to degrade heparan sulfate (HS), the main constituent of the extracellular matrix, providing a tumor microenvironment to tumor dissemination. In addition, this protein plays a significant role in the increase of tumor cells migration ionizing radiation dose delivery in radiotherapy from the increase in the expression levels of HPSE1. In order to evaluate in more detail the functions of active HPSE1, it has been proposed to characterize the interaction of human heparanase protein 1 with deoxyribonucleic acids. Our results are original and point to a new function of HPSE1 of the endonuclease type. (author)

  6. Performance of lead-acid batteries. Experimental study and discharge process modelling; Desempenho de baterias chumbo-acido. Estudo experimental e modelamento do processo de descarga

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, G; Bottura, C P [Universidade Estadual de Campinas, SP (Brazil); Oliveira, M G [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica

    1985-12-31

    Commercial lead-acid batteries performance when continuously discharge is valued in this work. The model relating battery capacity and discharge current is confirmed through the analysis of experimental results relating voltage to time for various discharge currents. Such model was determined for the tested batteries and can be interpreted in terms of diffusional limitations and plate passivation. (author). 2 figs., 1 tab., 12 refs

  7. The problem of auto-discharge in lead-acid batteries; O problema da auto-descarga em baterias chumbo acido

    Energy Technology Data Exchange (ETDEWEB)

    Avaca, L A; Gonzalez, E R; Tremiliosi Filho, G; Silva, C.C. da; Maezuru, M [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica e Quimica

    1985-12-31

    Storage batteries used together with photovoltaic cells in remote locations must have special characteristics to fit the charge and discharge profiles to which they are submitted. Therefore, to avoid over dimensioning of the photovoltaic cells, the batteries must have particularly low self-discharge characteristics. The problem of self-discharge is directly connected to the degree of technological development in the fabrication of the batteries. The self-discharge of the SLI batteries made locally was measured under standardized conditions and the results were correlated with the kinetics of the electrochemical hydrogen evolution reaction on the lead alloys in acid medium. (author). 7 figs., 4 tabs., 11 refs

  8. The importance of the fatty acids in breast milk and in lacteal formulae; La importancia de los acidos grasos en la leche materna y en las formulas lacteas

    Energy Technology Data Exchange (ETDEWEB)

    Vega, S.; Gutierrez, R.; Radilla, M.; Ramirez, A.; Perez, J. J.; Schettino, B.; Ramirez, M. L.; Ortiz, R.; Fontecha, J.

    2012-11-01

    The best choice for feeding the newborn child is breast milk, and when it is not possible to breast feed a baby, the breast milk is replaced by lacteal formula, which is why numerous studies focus their attention on the analysis of the diverse components of baby formula as well as functions in the breast fed baby. Fatty acids are components of great nutritional importance in the fetus and in the newborn child. Nowadays it is estimated that the fetus, during the last trimester of the gestational period and the newborn child, during the first six months of life, need a great contribution of araquidonic and docosahexaenoic acids, due to the fact that the speed of transformation of the predecessors to the hepatic level are not sufficient to cover the metabolic requirements of these fatty acids and it is the mother who contributes them through placental transport during gestation and her milk during lactation. The Organization of Food and Agriculture (FAO), the World Health Organization (WHO), the European Society of Gastroenterology, Hepato logy and Pediatric Nutrition (ESPGHAN) and the American Academy of Pediatrics recommend that lacteal formula imitate the composition of the breast milk, especially in the fatty polyunsaturated acids (PUFA). (Author) 61 refs.

  9. Production and characterization of an acido-thermophilic, organic solvent stable cellulase from Bacillus sonorensis HSC7 by conversion of lignocellulosic wastes

    Directory of Open Access Journals (Sweden)

    Fatemeh Azadian

    2017-06-01

    Full Text Available The acidophilic and thermophilic cellulase would facilitate the conversion of lignocellulosic biomass to biofuel. In this study, Bacillus sonorensis HSC7 isolated as the best thermophilic cellulose degrading bacterium from Gorooh hot spring. 16S rRNA gene sequencing showed that, this strain closely related to the B. sonorensis. CMCase production was considered under varying environmental parameters. Results showed that, sucrose and (NH42SO4 were obtained as the best carbon and nitrogen sources for CMCase production. B. sonorensis HSC7 produced CMCase during the growth in optimized medium supplemented with agricultural wastes as sole carbon sources. The enzyme was active with optimum temperature of 70 °C and the optimum CMCase activity and stability observed at pH 4.0 and 5.0, respectively. These are characteristics indicating that, this enzyme could be an acidophilic and thermophilic CMCase. Furthermore, the CMCase activity improved by methanol (166%, chloroform (152%, while it was inhibited by DMF (61%. The CMCase activity was enhanced in the presence of Mg+2 (110%, Cu+2 (116%, Triton X-100 (118% and it retained 57% of its activity at 30% NaCl. The compatibility of HSC7 CMCase varied for each laundry detergent, with higher stability being observed in the presence of Taj® and darya®. This enzyme, that is able to work under extreme conditions, has potential applications in various industries.

  10. Canaric acid (3,4-seco-lupane derivative) isolated from propolis of Ceara, BR; Acido canarico (3,4-seco derivado do lupano) em propolis do Ceara

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Irineu L. de; Alves, Leonardo A.; Lemos, Telma L.G.; Monte, Francisco J.Q. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: tlemos@dqoi.ufc.br; Braz-Filho, Raimundo [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacazes, RJ (Brazil). Centro de Ciencias e Tecnologia. Setor de Produtos Naturais

    2007-07-15

    Phytochemical investigation of a propolis sample from Alto Santo - Ceara, Brazil, allowed identification of triterpenes (lupeol, lupenone, germanicone, Canaric acid) and flavonoids (quercetin, kaempferol and acacetin), which were identified by spectroscopic data (IR, MS, and NMR, including 2D techniques). This is the first report of Canaric acid in propolis. Propolis extract and flavonoids showed antioxidant activity using a DPPH radical scavenging assay. (author)

  11. Radioprotection potential of the ascorbic acid on the carrageenan used as food additive; Potencial radioprotetor do acido ascorbico sobre a carragenana utilizada como aditivo alimenticio

    Energy Technology Data Exchange (ETDEWEB)

    Aliste, Antonio Joao; Mastro, Nelida Lucia del [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: ajaliste@net.ipen.br; nlmastro@net.ipen.br

    2002-07-01

    Carrageenans are a group of natural carbohydrates that are present in the structure of certain varieties of red algae (Rhodophyceae). They are used in emulsions, for syneresis control and to grow up, to promote adhesiveness and dispersion. In the industry of foods they can be used for instance, as thickness and gelling agents, alone or together with other additives. The processing of foods by radiation is increasing considerably, because the efficiency of the process in the industrial decontamination of products. The objective of this work was to study the action of the ascorbic acid as potential radioprotector of the carrageenan against {sup 60} Co gamma radiation effects, using the viscosity as parameter. Samples of commercial carrageenan dissolved at 1,0% were irradiated in the presence or not of ascorbic acid, with doses of 0.0 kGy; 1.0 kGy; 2.5 kGy; 5.0 kGy and 10.0 kGy. After the irradiation the relationships viscosity/dose were established for the temperature of 60 deg C. For the dose of 10.0 kGy a better protecting effect of the ascorbic acid on the carrageenan was seen. The implications of the use of this antioxidant is discussed as a form of minimizing the effect of the radiation in irradiated foods. (author)

  12. Estudio experimental para la obtención de dióxido de titanio a partir de ilmenita vía acido clorhídrico

    OpenAIRE

    Pedro Hernández; Andrés Hurtado; Luis Peñaloza; Jacqueline Romero

    2010-01-01

    Una ilmenita colombiana con un tamaño de partícula que pasa malla 100, se lixivió con soluciones de ácido clorhídrico cuyas concentraciones oscilaron entre 17% y el 41% (p/v), en relaciones estequiométricas de 1.0 a 2.5 veces, temperaturas entre 75°C y lOrC y tiempos de 1 a 5 horas. La mezcla resultante se filtró obteniéndose un licor que contenía entre 70% y 80% del TiO^ presente en la ilmenita, el cual se hidrolizó térmicamente. El producto final fue obtenido por calcinación a 900°C y po...

  13. Degradation of polylactic acid (Pla) at different doses of gamma radiation; Degradacion del acido polilactico (PLA) a diferentes dosis de radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Castillo R, Y.

    2015-07-01

    The excessive use of polymers such as polyethylene (PET), polystyrene (Ps) and recently the polylactic acid (Pla) that take more than 20 years to degrade, have caused great pollution in the environment. In this study the effects of gamma radiation in the Pla to different doses were studied, in order to reduce the degradation time of this polymer. The changes in physico-chemical structure of Pla during radiation were studied by thermo-gravimetric/Mass analysis; differential scanning calorimetry; scanning electron microscopy; X-ray dispersive analysis; infrared spectroscopy; X-ray diffraction and mechanical tests of hardness, elasticity and deformation. With scanning electron microscopy, the morphology of the Pla surface unirradiated was observed, in which an apparently smooth surface was observed, after changes that had the Pla when irradiated also was observed, where the effects of radiation were observed in form of scratch, agglomeration and small fractures. By X-ray dispersive analysis was determined and verified the elemental chemical composition of the Pla; as expected the tests showed only carbon, oxygen and hydrogen. With thermo-gravimetric/Mass analysis the decomposition temperatures of Pla were determined, identifying that the degradation compounds are CO, CO{sub 2} and CH{sub 4}. With infrared spectrometry the major peaks of Pla were observed before and after being irradiated with increasing of radiation dose the intensity of the bands decreased. Also by X-ray diffraction was observed that the polymer is an amorphous material. The mechanical tests indicate that the values of each of the tests decrease significantly with increasing the radiation dose. (Author)

  14. Use of chemical pre-treatment based chromic acid; Uso de pre-tratamento quimico a base de acido cromico. Beneficios versus desvantagens

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Paulo Henrique Leite [TENARIS CONFAB S.A., Pindamonhangaba, SP (Brazil); Bibiano, Paulo de Tarso [SOCO-RIL do Brasil S.A., Pindamonhangaba, SP (Brazil); Koebsch, Andre; Mollica, Eduardo de Oliveira [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2005-07-01

    In this work were going compared the polyethylene and FBE coatings performances in triple layer for tubes done with and without the presence of the pre-treatment chemist with chromic acid of the tube surface. The performance test chosen for accomplishes the comparison was the cathodic disbondment and hot water soak, for being this the test that has objective to improve the performance with the chromic acid application. The obtained results were going extracted of a factory database of TENARIS CONFAB S.A. in Pindamonhangaba - Sao Paulo. The adopted technical specification like reference for the tried coatings belonged to PETROBRAS S.A. Were compared also tests results of jobs using chromate and jobs that were not used pre-treatment. (author)

  15. PRODUCCIÓN DE ACIDO CLAVULÁNICO POR FERMENTACIÓN DE Streptomyces clavuligerus: EVALUACIÓN DE DIFERENTES MEDIOS DE CULTIVO Y MODELADO MATEMÁTICO

    Directory of Open Access Journals (Sweden)

    CLAUDIA PATRICIA SANCHEZ HENAO

    2012-01-01

    Full Text Available El ácido clavulánico (AC es un antibiótico b-lactámico con una potente capacidad inhibidora de la actividad b-lactamasa. En el presente trabajo se evaluaron cuatro medios de cultivo reportados en la bibliografía y uno propuesto por los autores, para la producción de AC. Se evaluó también la concentración de glicerol adecuada para el medio seleccionado y con base en los resultados obtenidos se realizó una evaluación de la producción de AC en un biorreactor de laboratorio. Se propuso un modelo matemático y se evaluó su ajuste a los resultados experimentales. Se observó que los medios complejos con presencia de una mezcla de aminoácidos libres, son adecuados para la producción de AC. El glicerol presentó un valor óptimo frente a la producción de AC en 50 g.L-1 y se observó el efecto inhibitorio a concentraciones de 100 g.L-1. Con el medio complejo y 50 g.L-1 de glicerol, la concentración de AC alcanzada fue de 994 mg.L-1. El modelo matemático propuesto que incluye una cinética tipo Contois para la biomasa y una cinética de formación de producto parcialmente asociado al crecimiento, presentan un ajuste significativo con un 95% de nivel de confianza.

  16. The influence of acid and base waste on the activated sludge system; Influencia de vertidos acidos y basicos sobre el sistema de fangos activados

    Energy Technology Data Exchange (ETDEWEB)

    Coello Oviedo, M. D.; Sales Marquez, D.; Quiroga Alonso, J. M.

    2003-07-01

    A study has been made of the effect of acid and base waste on the microorganisms in the activated sludge reactor. This effect was monitored using the classical control parameters (SVS and the percentage of organic matter eliminated) and by measuring the activity of the microorganisms (specific breathing rate and percentage of active cells). The results obtained indicate that the macrobiotic is affected at the extremes of the pH range (pH 4,5 and pH 10.5). The system's performance worsens and therefore the quality of the effluent fails to comply with European Directive 91/271/EEC. In the tests carried out with pH 6 and 9, the microorganisms activity declined at first,but the system eventually recovered and returned to levels of activity similar to those prior to the test. It was also found that deviations of the supply towards acid pH had a greater negative effect on the reactor than identical deviations towards baseness. (Author) 12 refs.

  17. Development of starch biofilms using different carboxylic acids as plasticizers; Desenvolvimento de biofilmes de amido utilizando como plastificantes diferentes acidos carboxilicos

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, L.C.; Miranda, C.S.; Santos, W.J. dos; Goncalves, A.P.B.; Oliveira, J.C.; Jose, N.M., E-mail: uanaconceicaocruz@gmail.com [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Programa de Pos-Graduacao em Engenharia Quimica. Grupo de Energia e Ciencias dos Materiais

    2014-07-01

    Biodegradable films have become a widely exploited issue among scientists because of their positive environmental impact, besides their potential to promote better food conservation and an increase in shelf life. Starch has been studied in this field due to its availability, low cost and biodegradability. However, starch films tend to be brittle and they need addition of a plasticizer to enable their usage. In this work, starch films were synthesized with different carboxylic acids as plasticizers, aiming to observe the effect of the acids chain size in the final films properties. The acids used were: oxalic, succinic and adipic. The materials were produced by casting and characterized by DSC, TG, DRX e FTIR. It was observed that the acids chain size influenced on the thermal and structural properties of the films. (author)

  18. COMPOSICION QUIMICA Y CONCENTRACION DE PRECURSORES DE ACIDO RUMENICO Y VACCENICO EN FORRAJES ALTERNATIVOS PARA LA ALIMENTACION DE RUMIANTES EN ECOSISTEMAS ARIDOS

    Directory of Open Access Journals (Sweden)

    Ricardo Ortega Pérez

    2009-07-01

    Full Text Available Se determinó el valor nutrimental de alfalfa henificada (AH, dos genotipos de fríjol yorimón [IT90K-277-2 (FYG18 y Sesenteño (FYG25], un clon de pasto taiwán (PT, un cultivar local de nopal en dos presentaciones, pencas tiernas de 15 días de edad o ";;;nopalitos";;; (NT y pencas maduras (NM de 60 días de edad y germinado de semillas de maíz (GM del genotipo ASGROW 7573. Se cuantificó el contenido de materia seca (MS, proteína cruda (PC, lípidos totales (LT, cenizas (C, fibra cruda (FC y energía bruta (EB, así como la concentración de ácido linoleico (LA, ácido α-linolénico (ALA, ácidos grasos poliinsaturados (PUFA y ácidos grasos n-3. Los resultados revelan que los genotipos de frijol yorimón FYG25 y FYG18, mostraron el mayor contenido de PC. Respecto a la concentración de LT, el genotipo de yorimón FYG25 mostró la mayor cantidad seguido del FYG18 y AH. Los forrajes verdes de frijol yorimón (FYG25 y FYG18, así como el pasto Taiwán tuvieron el contenido mayor de ácido α-linolénico. Las semillas de germinado de maíz mostraron los contenidos mayores de ácido linolénico seguido del nopal tierno. Ambos ácidos grasos poliinsaturados (ALA y LA son precursores del ácido ruménico y del ácido vaccénico en rumiantes. Por lo tanto, el uso de estos forrajes verdes en la alimentación de rumiantes es una alternativa que podría modificar las proporciones de ácido grasos en la leche y la carne con el propósito de incrementar los PUFA, específicamente el ácido ruménico así como el ácido vaccénico.

  19. Evolution of biochemical parameters in irradiated fishes: Serum proteins and intestinal nucleic acids; Evolucion de parametros bioquimicos en peces irradiados: Proteinas en suero y acidos nucleicos en intestino

    Energy Technology Data Exchange (ETDEWEB)

    Garces, F; Andres, P; Davila, C A

    1976-07-01

    In sublethal gamma-irradiated C. auratus, a sudden decrease of total serum protein concentration and a preferential descent of the low molecular weight gamma-globulin fraction have been observed. These effects are transient and after different latent periods dependent on doses, normal values are recovered, A temporal failure of a vascular permeability regulation system is probably implied. The DMA depolymerization. observed in the intestine indicates the action of radio-induced DNA degradation mechanisms since this effect is independent on doses. (Author) 29 refs.

  20. The impact of heavy and acid oil production in PETROBRAS downstream area; A influencia dos petroleos pesados e acidos no parque de refino da PETROBRAS

    Energy Technology Data Exchange (ETDEWEB)

    Perisse, Juarez Barbosa; Oddone, Maria Regina Rezende; Bela, Donizeti Aurelio Silva [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    PETROBRAS is facing a great challenge processing heavy and acid oils. The low API of the more recent offshore discoveries leads to an increase in vacuum residue yields which is one important component of the fuel oil's 'pool'. The fuel oil demand is expected to decrease along the next years due to natural gas substitution and to environmental issues, generating exceeding fuel oil exportation at low prices. This paper will discuss World and PETROBRAS technological choices to process these oils meeting the required future demand and quality. A comparison among various residue conversion technologies is also presented in this paper focused on the reduction of fuel oil production and on the improvement of diesel / gasoline rate. Another important issue that will be discussed in this paper is related to the different solutions implemented all over the world to deal with the crude acidity problem and the solutions adopted by PETROBRAS. (author)

  1. Polyesters production from the mixture of phthalic acid, terephthalic and glycerol; Producao de poliesteres a partir da mistura de acido ftalico, tereftalico e glicerol

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M., E-mail: adrianaequfba@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais; Carvalho, R.F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Escola Politecnica. Curso de Mestrado em Engenharia Ambiental Urbana

    2010-07-01

    Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

  2. Removing volatile fatty acids during the anaerobic treatment of pig sewage; Remocion de acidos grasos volatiles durante el tratamiento anaerobio de aguas residuales porcicolas

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Borges, E.; Mendez Novelo, R.; Magana Pietra, A.; Partinez Pereda, P.; Fernandez Villagomez, G. [Facultad de Ingenieria, Universidad Atuonoma de Yucatan. Mexico (Mexico)

    1997-06-01

    This study examined the behaviour of a hybrid anaerobic digester in treating pig farm sewage. The experimental model consisted of a 208-litre UASB reactor at the bottom and a 195-litre high-rate sedimentator at the top. The digester was installed on a pig farm and its efficiency in removing volatile (acetic and propionic) fatty acids (VFA) was determined with hydraulic retention time (HTR) as the critical parameter for evaluating the anaerobic system`s performance. The results obtained with the five different HRTs used during the experiment are reported. The highest removal rates were obtained with an HRT of 2.8 days: 98% in the UASB, 28% in the sedimentator and 98% in the digester as a whole. An HRT of 1 day gave VFA removal rates of 40%, 12% and 50% in the UASB reactor sedimentator and digest respectively. (Author) 16 refs.

  3. PROCESO ENZIMATICO PARA LA PRODUCCION DE METIL ESTERES DE ACIDOS GRASOS UTILIZANDO ACEITES RESIDUALES DE FRITURA EN MEZCLA CON ACEITE DE RAPS COMO MATERIA PRIMA

    OpenAIRE

    AZOCAR ULLOA; LAURA HAYDEE; AZOCAR ULLOA; LAURA HAYDEE

    2010-01-01

    Los procesos catalizados por lipasas han sido ampliamente investigados como alternativa para la producción de metil ésteres de ácidos grasos (fatty acid methyl ester, FAME) o biodiesel. El interés en este proceso radica en que a diferencia de los procesos convencionales catalizados con sales alcalinas, los procesos catalizados con lipasas permiten el uso de materias primas alternativas y de menor costo, tales como el aceite residual de fritura (waste frying oil, WFO). Pese a los l...

  4. Determinação da Fe 2 + e acido ascorbico e suas interações em sistemas modelo e natural (suco de laranja concentrado)

    OpenAIRE

    Lucia Helena Seron

    1991-01-01

    Resumo: Com o objetivo de conhecer as interações entre ácido ascórbico e Fe, a ser adicionado a suco de laranja concentrado, estudou-se a determinação desses compostos em soluções individuais e juntos na mesma solução, variando-se as condições do meio para avaliar suas interferências. As determinações de ácido ascórbico e Fe foram feitas pelo método da redução de íons cúpricos com cuproína enquanto somente os íons ferrosos foram determinados usando orto-fenantrolina. O sistema de uma fase nas...

  5. Estudio experimental para la obtención de dióxido de titanio a partir de ilmenita vía acido clorhídrico

    Directory of Open Access Journals (Sweden)

    Pedro Hernández

    2010-07-01

    Full Text Available Una ilmenita colombiana con un tamaño de partícula que pasa malla 100, se lixivió con soluciones de ácido clorhídrico cuyas concentraciones oscilaron entre 17% y el 41% (p/v, en relaciones estequiométricas de 1.0 a 2.5 veces, temperaturas entre 75°C y lOrC y tiempos de 1 a 5 horas. La mezcla resultante se filtró obteniéndose un licor que contenía entre 70% y 80% del TiO^ presente en la ilmenita, el cual se hidrolizó térmicamente. El producto final fue obtenido por calcinación a 900°C y posee un contenido de TiO^ mayor del 97%.

  6. Electrodialytic separation of Cu(II) and As(V) in acidic electrolytes; Separacion electrodialitica de Cu(II) y As(V) en electrolitos acidos

    Energy Technology Data Exchange (ETDEWEB)

    Ibanez, J. P.; Ipinza, J.; Cifuentes, L.

    2007-07-01

    The separation of copper and arsenic from acidic electrolytes by electrodialysis was investigated at room temperature. the effect of current density and pH was studied in a batch cell during 3 hours. The kinetic parameters showed that Cu(II) transport rate was 0.75 mol/m''2/h and the As(V) transport rate was 0.002 mol/m''2/h. An efficient separation between Cu(II) and As(V) was achieved; Generating a concentrated solution of copper with no arsenic, which was obtained independently of the electrolyte acidity and current density used. The effect of the arsenic speciation with pH is discussed as well. (Author) 23 refs.

  7. Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid; Estudo in vitro da microinfiltracao marginal em cavidades classe V preparadas com laser de Er:YAG e condicionadas com acido ou com laser de Er:YAG e acido

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Henrique Dutra Simoes

    2001-07-01

    Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0-3) by three calibrated examinators. Both results on occlusal and gingival margins have shown no statistic significant difference among the three groups evaluated (p>0.05). The Er:YAG laser have shown to be as effective as the conventional methods for cavity preparation and etching, suggesting its use for the class V cavity preparation and enamel etching. (author)

  8. Impregnation of 12-tungstophosphoric acid on silica - part II: effect of different solvents on the impregnation and catalytic activity in methyl esterification of stearic acid; Impregnacao do acido 12-tungstofosforico em silica - parte II: efeito de diferentes solventes na impregnacao e atividade catalitica na esterificacao metilica de acido estearico

    Energy Technology Data Exchange (ETDEWEB)

    Scroccaro, Karine Isabel; Yamamoto, Carlos I., E-mail: karineisabel@yahoo.com.br [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Centro Politecnico. Departamento de Engenharia Quimica; Tanobe, Valcineide O. de A.; Oliveira, Alan Antonio de [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Departamento de Engenharia e Tecnologia Florestal; Wypych, Fernando [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Departamento de Quimica

    2014-04-15

    Materials obtained by the immobilization of 12-tungstophosphoric acid (PTA) on silica using the method of impregnation with excess solution in distinct solvents (aqueous HCl, methanol:H{sub 2}O, and acetonitrile) were evaluated for use as catalysts in the methyl esterification of stearic acid. Optimum conditions were established for the impregnation of 0.5 g (w/w) of PTA on amorphous silica, under stirring at 150 rpm for 24 h, using 20 mL of 0.1 mol L{sup -1} HCl as the solvent. After calcination at 200 deg C, high conversions were obtained under mild reaction conditions, resulting in high turnover numbers. The catalyst was evaluated in ten catalytic cycles of use, where the activity was reduced only slightly, attesting its stability and the possibility to apply it to industrial production of methylesters. (author)

  9. Development of methodology for the synthesis of poly(lactic acid-co-glycolic acid) for use in the production of radioactive sources; Desenvolvimento da metodologia para sintese do poli(acido latico-co-acido glicolico) para utilizacao na producao de fontes radioativas

    Energy Technology Data Exchange (ETDEWEB)

    Peleias Junior, Fernando dos Santos; Zeituni, Carlos Alberto; Rostelato, Maria Elisa Chuery Martins; Souza, Carla Daruich de; Mattos, Fabio Rodrigues de; Moura, Eduardo Santana de; Moura, Joao Augusto; Benega, Marcos Antonio Gimenes; Feher, Anselmo; Costa, Osvaldo Luiz da; Rodrigues, Bruna Teiga, E-mail: fernandopeleias@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP/CTR), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes; Fechine, Guilhermino Jose [Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil). Escola de Engenharia

    2015-05-15

    According to the World Health Organization, cancer is a leading cause of death worldwide. A radiotherapy method extensively used in prostate cancer is brachytherapy, where the area requiring treatment receives radioactive seeds. Iodine-125 seeds can be inserted loose or stranded in bioabsorbable polymers produced from poly(lactic-co-glycolic acid) (PLGA). We developed the synthesis methodology for PLGA and the results obtained show that it was possible to determine the optimal reaction parameters (time and temperature) for PLGA in 80/20 (lactide/glycolide) ratio. The yield was higher than 90% using a temperature of 110 °C and reaction time of 72 hours; however, the molecular weight values obtained are very low compared to those obtained by other authors. New tests using previously synthesized dimers and nitrogen atmosphere are being performed. These conditions could potentially increase the molar mass of PLGA. All techniques used confirmed the expected structure of the polymer. (author)

  10. Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid; Estudo in vitro da microinfiltracao marginal em cavidades classe V preparadas com laser de Er:YAG e condicionadas com acido ou com laser de Er:YAG e acido

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Henrique Dutra Simoes

    2001-07-01

    Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0-3) by three calibrated examinators. Both results on occlusal and gingival margins have shown no statistic significant difference among the three groups evaluated (p>0.05). The Er:YAG laser have shown to be as effective as the conventional methods for cavity preparation and etching, suggesting its use for the class V cavity preparation and enamel etching. (author)

  11. Composicao quimica, perfil de acidos graxos e quantificacao dos acidos ƒ¿-linolenico, eicosapentaenoico e docosahexaenoico em visceras de tilapias (Oreochromis niloticus = Percentual composition, fatty acids and quantification of the LNA (Alfa-Linolenic, EPA (Eicosapentaenoic and DHA (Docosahexaenoic acids in visceras of Nile Tilapia (Oreochromis niloticus

    Directory of Open Access Journals (Sweden)

    Nilson Evelázio de Souza

    2005-01-01

    Full Text Available Foi avaliada a composição química de vísceras de tilápias (Oreochromis niloticus criadas em cativeiro Os teores de umidade, cinza, proteína bruta e lipídios totais foram de 64,4%; 1,3%; 6,3% e 18,0%, respectivamente, caracterizando alta concentração de lipídiostotais em relação a outros resíduos de peixes. Foram identificados 49 ácidos graxos, sendo majoritários os ácidos: oléico, (32,8%, seguido do palmítico, (19,9% e linoléico, (18,2%. As razões entre n-6/n-3 e ácidos poliinsaturados/saturados foram de 5,5 e 0,9, respectivamente. As quantificações dos ácidos graxos alfa-linolênico, eicosapentaenóico e docosahexaenóico, em mg/g de lipídios totais, foram de 10,4, 1,4 e 9,3, respectivamente. O elevado teor de lipídios totais das vísceras contribuiu significativamente para as quantidadesde ácidos graxos n-3. Todos os parâmetros analisados foram satisfatórios sob o ponto de vista nutricional e neste sentido as vísceras de tilápias poderão ser utilizadaa para alimentar peixes ou outros animais.The chemical composition was evaluated in visceras of tilapias raised in captivity. The moisture, ash, crude protein and total lipids contents were 64.4%; 1.3%; 6.3% and 18.0%, respectively, characterizing high total lipids concentration in relation other residues of fish. Forty nine fatty acids were detected, the major fatty acids were oleic (32.8%, palmitic (19.9% and linoleic-1 (18.2% and oleic (9.4%. The ratio n-6/n-3 and polyunsaturated/saturated fatty acids, showed the values 5.5 and 0.9, respectively. The quantifications of alfa-linolenic, eicosapentaenoic and docosahexaenoic acids (in mg/g of total lipids, were 10.4, 1.4 and 0.3, respectively. The higher contents of total lipids in visceras contributed significantly for amounts of n-3 fatty acids. All the parameters analyzed were shown nutritional value satisfactory in this sense visceras of tilapias can be used in the feed of fish and other animal.

  12. Optimized Analytical Method to Determine Gallic and Picric Acids in Pyrotechnic Samples by Using HPLC/UV (Reverse Phase); Optimizacion del Metodo Analitico mediante HPLC/UV Operando en Fase Inversa para la Determinacion de Acido Galico y Acido Picrico en Muestras de Origen Pirotecnico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Alonso, S.; Perez Pastor, R. M.

    2013-10-01

    A study on the optimization and development of a chromatographic method for the determination of gallic and picric acids in pyrotechnic samples is presented. In order to achieve this, both analytical conditions by HPLC with diode detection and extraction step of a selected sample were studied. (Author)

  13. Liquid-liquid extraction (LLE) of Fe(III) and Ti(IV) by bis-(2-ethyl-hexyl) phosphoric acid (D2EHPA) in sulfuric acid medium; Extracao liquido-liquido de ferro (III) e titanio (IV) pelo acido bis-(2-etil-hexil) fosforico (D2EHPA) em meio de acido sulfurico

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Glauco Correa da; Cunha, Jose Waldemar Silva Dias da [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil). Dept. de Quimica e Materiais Nucleares; Dweck, Jo [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica. Dept. de Processos Inorganicos; Afonso, Julio Carlos [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica. Dept. de Quimica Analitica]. E-mail: julio@iq.ufrj.br

    2008-07-01

    This work presents a study on the separation of Fe(III) and Ti(IV) from sulfuric acid leaching solutions of ilmenite (FeTiO{sub 3}) using liquid-liquid extraction with D2EHPA in n-dodecane as extracting agent. The distribution coefficients (K{sub D}) of the elements related to free acidity and concentration of Fe(III) and Ti(IV) were determined. Free acidity was changed from 3x10{sup -2} to 11.88 mol L{sup -1} and D2EHPA concentration was fixed at 1.5 mol L{sup 1}. Recovery of final products as well as recycling of wastes generated in the process were also investigated. The LLE process as a feasible alternative to obtain high-purity TiO{sub 2}. (author)

  14. Development of methodology for the synthesis of poly(lactic acid-co-glycolic acid) for use in the production of radioactive sources; Desenvolvimento da metodologia para sintese do poli(acido latico-co-acido glicolico) para utilizacao na producao de fontes radioativas

    Energy Technology Data Exchange (ETDEWEB)

    Peleias Junior, Fernando dos Santos

    2013-07-01

    According to World Health Organization (WHO), cancer is a leading cause of death worldwide. Prostate cancer is the second most common cancer in men. A method of radiotherapy which has been extensively used is brachytherapy, where radioactive seeds are placed inside the area requiring treatment. Iodine-125 seeds can be placed loose or stranded in bioabsorbable polymers. Stranded seeds show some advantages, since they reduce the rate of seed migration, an event that could affect the dosimetry of the prostate and cause unnecessary damage to healthy tissues or organs. For Iodine-125 stranded seeds, polyglactin 910 (poly(lactic-co-glycolic acid)) (PLGA), with a coverage of polyglactin 370 (Vicryl Registered-Sign ) is used. It was purposed in this dissertation, the study and development of the synthesis methodology for PLGA via ring-opening polymerization, as well as its characterization, with the objective of using the synthesized material to manufacture a material similar to RAPID Strand{sub Registered-Sign }. The results obtained show that it was possible to determine the optimal reaction parameters (time and temperature) for PLGA in 80/20 (lactide/glycolide) ratio. Using a temperature of 110 Degree-Sign C and reaction time of 24h, a yield of 86% was obtained, and increasing the reaction time to 72 hours, the yield was higher than 90%. The molecular mass values obtained from the samples are still very low compared to those obtained by other authors in the literature (about 20%). Failures in the sealing of vials, leaving them vulnerable to moisture and oxygen, or lack of an efficient stirring system might be possible explanations for these results. A suitable chemical reactor could solve the problem. Regarding polymer characterization, all techniques used not only confirmed the expected structure of the polymer, but also showed the highest proportion of lactide units compared to to glycolide units. (author)

  15. Biosynthetic origin of acetic acid using SNIF-NMR; Determinacao da origem biossintetica de acido acetico atraves da tecnica 'Site Specific Natural Isotopic Fractionation Studied by Nuclear Magnetic Resonance (SNIF-NMR)'

    Energy Technology Data Exchange (ETDEWEB)

    Boffo, Elisangela Fabiana; Ferreira, Antonio Gilberto [Sao Carlos Univ., SP (Brazil). Dept. de Quimica

    2006-05-15

    The main purpose of this work is to describe the use of the technique Site-Specific Natural Isotopic Fractionation of hydrogen (SNIF-NMR), using {sup 2}H and {sup 1}H NMR spectroscopy, to investigate the biosynthetic origin of acetic acid in commercial samples of Brazilian vinegar. This method is based on the deuterium to hydrogen ratio at a specific position (methyl group) of acetic acitained by fermentation, through different biosynthetic mechanisms, which result in different isotopic ratios. We measured the isotopic ratio of vinegars obtained through C{sub 3}, C{sub 4}, and CAM biosynthetic mechanisms, blends of C{sub 3} and C{sub 4} (agrins) and synthetic acetic acid. (author)

  16. 15-demethylisoplumieride acid, a new iridoid isolated from the bark of Plumeria rubra and latex of Himatanthus sucuuba; Acido 15-desmetilisoplumierideo, um novo iridoide isolado das cascas de Plumeria rubra e do latex de Himatanthus sucuuba

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, Alaide de Sa; Amaral, Ana Claudia F. [Fundacao Inst. Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil). Instituto de Tecnologia em Farmacos -Farmanguinhos. Lab. de Plantas Medicinais e Derivados; Silva, Jefferson Rocha de A. [Universidade Federal do Amazonas, Manaus, AM (Brazil). Dept. de Quimica]. E-mail: jrocha_01@ufam.edu.br; Schripsema, Jan [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacazes, RJ (Brazil). Setor de Quimica de Produtos Naturais; Rezende, Claudia M.; Pinto, Angelo C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica

    2007-09-15

    Himatanthus sucuuba and Plumeria rubra are used in folk medicine in Brazil to treat various ailments. The isolation of the new iridoid 15-demethylisoplumieride from the bark of Plumeria rubra L. var. acutifolia (Ait) Woodson and latex of Himatanthus sucuuba (Spruce) Woodson is reported. Other iridoid glycosides were obtained from both plants. The structures of these substances were elucidated by spectral analysis and comparison with data already reported. (author)

  17. Evaluation of gamma irradiation effects on carotenoids, ascorbic acid and sugar contents of buriti fruit (Mauritia flexuosa L.); Avaliacao dos efeitos da radiacao gama nos teores de carotenoides, acido ascorbico e acucares do fruto Buriti do Brejo (Mauritia flexuosa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Antonio Luis dos Santos [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Quimica, Quimica Organica e de Produtos Naturais], e-mail: santoslima@ime.eb.br; Lima, Keila dos Santos Cople; Silva, Jaqueline Michele [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear. Irradiacao de Alimentos], e-mail: keila@ime.eb.br, e-mail: jaquelinefisica@bol.com.br; Coelho, Maysa Joppert [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear. Engenharia Ambiental], e-mail: maysa@ime.eb.br; Godoy, Ronoel Luiz de Oliveira [EMBRAPA Agroindustria de Alimentos, Rio de Janeiro, RJ (Brazil). Lab. de Cromatografia Liquida, Quimica Organica e de Produtos Naturais], e-mail: ronoel@ctaa.embrapa.br; Pacheco, Sidney [EMBRAPA Agroindustria de Alimentos, Rio de Janeiro, RJ (Brazil). Lab. de Cromatografia Liquida, Ciencia e Tecnologia de Alimentos], e-mail: sidney@ctaa.embrapa.br

    2009-07-01

    Buriti (Mauritia flexuosa L.), a typical fruit from the Northeast and Center-West Amazon of Brazil, is used in many regional dishes. It is considered an excellent source of carotenoids that are A vitamin precursors, showing a majority of beta-carotene. It also presents ascorbic acid and sugar contents. Many studies have indicated that the lack of A vitamin is the main cause of night blindness and xerophthalmia. Also, ascorbic acid deficiency may cause scorbutic disease. The use of food irradiation is growing and represents an economic benefit to agriculture through the reduction of post-harvesting losses while maintaining food nutritional quality. In this study, buriti in natura was treated with gamma irradiation with doses of 0.5 kGy and 1.0 kGy. The objective was to evaluate the irradiation effects on total carotenoids, ascorbic acid and sugars concentrations of buriti. The fruit was evaluated through the total carotenoids analysis, by spectrophotometry, and the carotenoids (alpha and beta-carotene and lutein), ascorbic acid and sugars were determined by high performance liquid chromatography (HPLC). The results showed that buriti is an excellent source of total carotenoids (44600 {mu}g/100 g). The irradiation of buriti with the dose of 0.5 kGy did not significantly change carotenoids and sugars contents. However, there was a reduction of ascorbic acid concentration with an increase of the dose, which may have been caused by irradiation or by intrinsic and extrinsic factors that alter ascorbic acid stability in food, converting ascorbic to dehydroascorbic acid, while keeping the C vitamin active form. (author)

  18. Zirconia silicate modified with phytic acid (IP6) and its effect on uranyl sorption; Silicato de circonio modificado con acido fitico (IP6) y su efecto en la sorcion de uranilo

    Energy Technology Data Exchange (ETDEWEB)

    Escalante G, D. C.

    2016-07-01

    In this work the sorption capacity of uranyl ions on zirconium silicate (ZrSiO{sub 4}) extracted from sea sand of Baja California Sur was studied, the effect of phytic acid (IP6) accompanied by a perchlorate salt of sodium (NaClO{sub 4}) on the surface of the mineral. In the first stage, ZrSiO{sub 4} was obtained from sea sand by extraction using hydrofluoric acid, the purified and hydrated material was later characterized by instrumental techniques such as X-ray diffraction to determine its purity and crystallinity. The ZrSiO{sub 4}-purified, ZrSiO{sub 4}/NaClO{sub 4} and ZrSiO{sub 4}/IP6 were studied by physicochemical and surface characterization. By scanning electron microscopy was observed that ZrSiO{sub 4} initially is formed by flat structures, however, when it is hydrated with NaClO{sub 4} the formation of particles on the material exists, whereas when the IP6 is added the crystals on the surface are elongated forming structures geometric shapes. This modification on the surface of the ZrSiO{sub 4} was corroborated by atomic force microscopy where significant changes were observed in the topography of the purified and hydrated material. By Fourier transform infrared spectroscopy is identifies the presence of functional groups from hydration with IP6 and NaClO{sub 4} on the surface of SrSiO{sub 4}. Characterization of surface properties was performed by determining the surface area of the purified ZrSiO{sub 4}, SrSiO{sub 4}/NaClO{sub 4} and ZrSiO{sub 4}/IP6 systems using the Bet multipoint and fractal dimension technique; the hydration time, zero loading point was evaluated by means of a bulk titration and surface site density (Ds). The fluorescence and phosphorescence techniques allowed determining the optimum hydration point and the uranium species sorbed on the surface of the ZrSiO{sub 4} as in the systems hydrated with IP6 and with NaClO{sub 4}. This technique provided relevant information about the speciation and complex formation of IP6 with uranyl ions on the surface of ZrSiO{sub 4}. Sorption isotherms and kinetics were prepared by the liquid scintillation technique, and this technique allowed corroborating the quantification of uranium at the surface. Surface acidity constants at the solid/liquid interface for both systems were obtained by modeling the acid-base titration curves with FiTEQL 4.0 software, where the chemical species and complexes formed on the mineral surface were identified. The results show that the ZrSiO{sub 4}/NaClO{sub 4} system has a maximum percentage of 98.8% sorption at ph 7, whereas with the proposed system ZrSiO{sub 4}/IP6 it was 99.2% from a ph of 3, from an initial concentration of uranium of 1 x 10{sup -3} M. (Author)

  19. Sterols and fatty acids analysis at the Llobregat River for a wastewater dumping episode; Analisis de esteroles y acidos grasos en el rio Llobrgat por un vertido de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Lacal, J.; Garcia-Mendi, C.; Vega, A.; Pujadas, M.

    2006-07-01

    The study by gas chromatography (HRGC) and mass spectrometry (MS) of fatty acids and sterols of water samples from Anoia and Llobregat River, allowed to rule out the hypothesis of the Anoia River as the cause of dumping episode and even to determine that the episode was not associated to the faecal or residual contamination. Nevertheless, it has permitted us to have a better knowledge of these families of organic compounds in the basin of the Llobregat River. In the acidic fraction, saturated and unsaturated fatty acids of 14, 16 and 18 atoms of carbon from oil fish, animal fat or hydrogenated oils with industrial and domestic use were found. The application of different sterols indices (coprostanol, cholesterol, cholestanol, stigmasterol, stigmastadienol and sitosterol) permitted us to study the role of the sterols and the significance of the contamination from animal sterols, fitosterols in the studied samples. (Author) 19 refs.

  20. Determinações simultaneas de acidos em misturas por titulações potenciometricas e suas aplicações a analises de antiacidos, sucos de uva e vinhos

    OpenAIRE

    Nilson Evelazio Souza

    1985-01-01

    Resumo: Os vários métodos matemáticos e gráficos usados no tratamento dos dados de titulações potenciométricas são discutidos. Um método algébrico linear foi utilizado na deterninação de várias misturas sintéticas visando a aplicação em matrizes reais. Foram estudadas as determinações simultâneas dos ácidos em várias misturas dos ácidos clorídrico, tartárico, málico, succínico e cítrico. Os valores de pKa destes ácidos foram determinados em meio 1,0 M de NaNO3, tendo em vista o ajuste de forç...

  1. Impregnation of 12-tungstophosphoric acid on silica - part I: determination of impregnation parameters, characterization and evaluation of catalytic activity; Impregnacao do acido 12-fosfotungstico em silica - parte I: determinacao de parametros de impregnacao, caracterizacao e avaliacao da atividade catalitica

    Energy Technology Data Exchange (ETDEWEB)

    Scroccaro, Karine Isabel; Tanobe, Valcineide Oliveira de Andrade; Cocco, Lilian Cristina; Yamamoto, Carlos Itsuo, E-mail: karineisabel@yahoo.com.br [Universidade Federal do Parana, Curitiba, PR (Brazil). Centro Politecnico. Dept. de Engenharia Quimica; Wypych, Fernando [Universidade Federal do Parana, Curitiba, PR (Brazil). Centro Politecnico. Dept. de Quimica

    2012-07-01

    Catalyst based on Kegging-type heteropolyacids (H{sub 3}PW{sub 12}O{sub 40} - HPA), supported on SiO{sub 2} (H{sub 3}PW), were prepared by the impregnation method under different thermal treatment conditions. The materials were characterized by different instrumental techniques and used as catalysts in the methyl esterification reactions of stearic acid. Using the catalyst with 15% of HPA, conversions higher than 60% were obtained after 2 h of reaction at 65 deg C. Recovery studies using hot-filtration with ethanol at 75 deg C showed satisfactory activity for two additional reaction cycles. (author)

  2. Niobium (V) doped bioceramics: evaluation of the hydrothermal route modified with citric acid and urea to obtain modified hydroxyapatite; Bioceramicas aditivadas com niobio (V): avaliacao da rota hidrotermica modificada com acido citrico e ureia para obtencao de hidroxiapatitas modificadas

    Energy Technology Data Exchange (ETDEWEB)

    Simomukay, E.; Souza, E.C.F. de; Antunes, S.R.M.; Borges, C.P.F.; Michel, M.D.; Antunes, A.C. [Universidade Estadual de Ponta Grossa (UEPG), Ponta Grossa, PR (Brazil)

    2016-01-15

    Synthetic hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}; HA) has become a widely used ceramic material for bone reconstruction due to its biocompatibility with the bone tissue. This biocompatibility as well as other physical and chemical properties of the hydroxyapatite can be modified by the addition of different ions to its structure. Niobium (V) ion has not been commonly used in the hydroxyapatite synthesis. The objective of this study was to evaluate the use of hydrothermal route in the niobium (V) doped hydroxyapatite synthesis. The route used the niobium ammonium oxalate (NH{sub 4}H{sub 2}[NbO(C{sub 2}O{sub 4}){sub 3}].3H{sub 2}O) complex as a niobium (V) ion precursor. The addition of citric acid and urea in the hydrothermal route is used for the control of synthesis pH and precipitation rate. Pure sample and sample added with 5.3 ppm of niobium (V) ion were prepared. The coexistence of other phases besides the hydroxyapatite was not observed in any of the samples through the use of X-ray diffraction and infrared spectroscopy (FTIR) techniques. The FTIR technique revealed the presence of hydroxyapatite characteristic functional groups. The scanning electron microscopy analysis showed the formation of agglomerates composed of round particles, confirmed by the transmission electron microscopy technique. The X-ray fluorescence spectroscopic analysis detected the presence of niobium in the doped sample. The results showed that niobium (V) doped hydroxyapatite can be synthesized by means of hydrothermal route, which may be considered as huge potential for future application in bioceramics. (author)

  3. Modified montmorillonite as a heterogeneous catalyst in (m)ethyl esterification reaction of lauric acid; Montmorilonita modificada como catalisador heterogeneo em reacoes de esterificacao (M)etilica de acido laurico

    Energy Technology Data Exchange (ETDEWEB)

    Zatta, Leandro; Nepel, Angelita; Barison, Andersson; Wypych, Fernando, E-mail: wypych@ufpr.br [Departamento de Quimica, Universidade Federal do Parana (UFPR), Curitiba , PR (Brazil)

    2012-07-01

    Montmorillonite was modified with zirconium polyoxycations in the presence of ammonium sulphate. The material was characterized and used as a catalyst in the esterification of lauric acid, the reactions being accompanied by 2{sup 3} factorial design. Conversions of up to 95.33 and 83.35% were observed for the methyl and ethyl esterification reactions respectively, proving superior to results obtained by thermal conversion. The material was submitted to three reaction cycles and similar conversions were observed, indicating the catalyst is not significantly deactivated after reuse. The catalyst was also tested under reflux conditions, yielding a maximum conversion of 36.86%. (author)

  4. Modeling of an immobilized lipase tubular reactor for the production of glycerol and fatty acids from oils; Modelado de un reactor tubular de lipasas inmovilizadas para la produccion de glicerol y acidos grasos a partir de aceites

    Energy Technology Data Exchange (ETDEWEB)

    Oddone, S.; Grasselli, M.; Cuellas, A.

    2010-07-01

    Advances in the design of a bioreactor in the fats and oils industry have permitted the hydrolysis of triglycerides in mild conditions and improved productivity while avoiding the formation of unwanted byproducts. The present work develops a mathematical model that describes the hydrolytic activity of a tubular reactor with immobilized lipases for the production of glycerol and fatty acids from the oil trade. Runge Kuttas numerical method of high order has been applied, considering that there is no accumulation of the substratum in the surface of the membrane, where the enzyme is. At the same time, different equations based on the kinetic model of Michaelis Mentens and the Ping-Pong bi-bi mechanism were examined. Experimental data in discontinuous systems are the basis for the development of the quantitative mathematical model that was used to simulate the process computationally. The obtained results allow for optimizing both the operative variables and the economic aspects of industrial processes. (Author)

  5. Gamma radiation effects at color, antioxidant capacity and fatty acid profile in peanut (Arachis hypogaea L.); Efeitos da radiacao gama na cor, capacidade antioxidante e perfil de acidos graxos em amendoim (Arachis hypogaea L.)

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Adriano Costa de; Canniatti-Brazaca, Solange Guidolin; Mansi, Debora Niero; Domingues, Maria Antonia Calori [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Agroindustria, Alimentos e Nutricao; Arthur, Valter, E-mail: arthur@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2011-01-15

    Irradiation is efficient at extinction fungi contamination in peanuts. Peanuts have high biologic value protein, minerals, vitamin E, complex B, and high concentration of lipids. The objective of this research is to evaluate the gamma irradiation effect on color, total phenolic, antioxidant activity, and fatty acid profile in peanuts (Arachis hypogaea L.). Cultivars IAC-Tatu ST and IAC-Runner 886 were submitted to gamma radiation with doses of 5.0; 7.5; 10.0, and 15.0 kGy and storage at room temperature. There was no significant difference in the color of IAC-Tatu ST. However, significant difference was found in the luminosity and Chroma in IAC-Runner 886. Total fenolics differed from the control with 33.27 mg.g{sup -1} and treatment dose of 10.0 kGy with 58.60 mg.g{sup -1} in IAC-Tatu ST. This parameter not had significant difference in IAC-Runner 886 and the control with 51.59 mg.g{sup -1}. The antioxidant activity did not present significant difference with a dose of 10.0 kGy, recommended for the elimination of fungi in peanuts. The dose of 10.0 kGy showed a decrease in saturated fatty acids, increase in unsaturated fatty acids, and an increase in linolleic acid. The oleic/linoleic relation decreased justifying further research correlating storage and oxidative stability. (author)

  6. Behavior of uranium isotopes along a tidal cycle in a study affected by acid mine drainage; Comportamiento de los isotopos de uranio a lo largo de un ciclo mareal en un estuario afectado por denaje acido de minas

    Energy Technology Data Exchange (ETDEWEB)

    Hierro, A.; Martin, J. e.; Olias, M.; Garcia, C.; Bolivar, J. P.

    2013-07-01

    The Tinto and Odiel rivers converge in an estuarine system known as the Ria de Huelva, which is an ecosystem of great interest, conditioned by hydrochemical facts. The main objective of this study was to analyze the behavior of uranium isotopes in the waters of the Red River estuary in a tidal cycle under hydrochemical conditions of high gradients of salinity and pH generated by the acidic waters of the Rio Tinto and seawater. (Author)

  7. Effect of niobium addition to the Fe-17% Cr alloy on the resistance to generalized corrosion in sulfuric acid; Efeito da adicao de niobio a liga Fe-17% Cr sobre a resistencia a corrosao generalizada em acido sulfurico

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Neusa; Wolynec, Stephan

    1993-12-31

    The aim of present work was to investigate the influence of Nb upon the corrosion resistance to o.5 M H2 SO{sub 4} cf 17% Cr ferritic stainless steels, to which it was added in amounts larger than those necessary for the stabilization of interstitial elements. The performance of Fe-17% Cr alloys containing 0.31%, 0.58%, 1.,62% Nb was compared to that of two other Fe-17% Cr alloys containing 0.31%, 0.58% and 1.62% Nb was compared to that of two other Fe-175 Cr alloys, one without additions and another containing 0.93% Nb. Through weight and electrochemical measurements and through morphologic examination of corroded surface it was found that in o.5 M H{sub 2} SO{sub 4} solution the corrosion of these alloys, with the exception of that containing molybdenum, products in two different stages. In the first stage (up to about 60 minutes) the rate practically does not change with time, the lower rates being displayed by alloys containing larger mounts of Nb. In the second stage (for immersion times larger than 60 minutes) the corrosion rate increases with time. the corrosion rate of Mo containing alloy is constant with time so that for longer immersion times this alloy becomes the most resistant. The first stage was discussed in terms of electromechanical properties of Nb and its ability to combine with steel impurities, while the second stage was considered as affected by corrosion products formed on the surface of these alloys after certain time of immersion. (author) 24 refs., 1 fig., 3 tabs.

  8. REVIEW. BACTERIAS ACIDO LÁCTICAS: PAPEL FUNCIONAL EN LOS ALIMENTOS BACTÉRIAS ÁCIDO LÁCTICAS: PAPEL FUNCIONAL NOS ALIMENTOS REVIEW LACTIC ACID BACTERIA: FUNCTIONAL ROLE IN THE FOODS

    OpenAIRE

    RICARDO ADOLFO PARRA HUERTAS

    2010-01-01

    Las bacterias ácido lácticas han sido importantes en los alimentos por siglos por su considerable contribución al valor de los productos. Debido a varias de sus propiedades metabólicas, las bacterias ácido lácticas desempeñan un papel importante en la industria alimentaria, por su contribución significante al sabor, olor, textura, características sensoriales, propiedades terapéuticas y valor nutricional de los productos alimentarios. Este grupo está compuesto de un número de géneros incluyend...

  9. La ruta de señalización del acido salicílico juega un papel importante en la resistencia en tomate a Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) mediada por el gen Mi-1

    OpenAIRE

    Muñiz, Mariano; Rodriguez, C.I.; Kaloshian, I.; Nombela, Gloria

    2009-01-01

    Es bien conocido que la resistencia en tomate a Bemisia tabaci (Gennadius), a Macrosiphum euphorbiae (Thomas) y a tres especies de nematodos formadores de nódulos (Meloidogyne spp.) está mediada por el gen Mi-1. Asimismo, está documentado que el ácido salicílico interviene en los mecanismos de resistencia frente a nematodos formadores de nódulos y áfidos. Recientemente se ha descrito que, en Arabidopsis, el biotipo B de B. tabaci induce defensas activadas por este ácido e inhibe las del ácido...

  10. Obtention of Samarium and Gadolinium concentrates by solvent extraction using mono-2-ethylhexyl ester of 2-ethylhexyl phosphonic acid; Obtencao de concentrados de samario e gadolinio via extracao por solventes com o ester mono-2-etilhexil do acido 2-etilhexilfosfonico

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Junior, Pedro

    1996-07-01

    The rare earth chlorides solution employed in this study, which is constituted by medium and heavy fractions, is derived from monazite processing accomplished by NUCLEMON-Mineroquimica (SP). This solution shows an acidity about 1.18 M and 189 g/L of rare earth oxides, containing as main constituents: Sm(34.55%), Gd(23.85%), Dy (6.82%), and Y (24.45%). It was used, as organic phase, 2-ethylhexyl phosphonic acid, mono-2-ethylhexylester diluted to 1 M in isododecane. (author)

  11. Acido tranexâmico e hemostasia em cirurgia de revascularização do miocárdio com circulação extracorpórea Tranexamic acid and hemostasis in myocardial revascularization with extracorporeal circulation

    Directory of Open Access Journals (Sweden)

    Guilherme F Vargas

    1992-12-01

    Full Text Available O antífibrinolítico sintético ácido tranexâmico (Transamin ® foi avaliado em seus efeitos hemostáticos e poupadores de transfusões homólogas, em pacientes submetidos a revascularização do miocárdio com circulação extracorpórea (CEC. Quarenta pacientes receberam placebo e 55 pacientes foram operados sob o efeito do ácido tranexâmico na dose de 10 g endovenosa no trans-operatório (2 g administrados na indução anestésica e os restantes 8 g nas 4 horas seguintes de cirurgia, de modo contínuo. O ácido tranexâmico, na dosagem utilizada, demonstrou possuir efeito hemostático impressionante, promovendo uma redução no débito pelos drenos torácicos da ordem de 47% nas 12 horas de P.O., 42,5% nas 24 horas de P. O. e 40,5% até a retirada dos drenos, em relação ao grupo-controle (pThe synthetic antif ibrinolytic drug tranexamic acid was evaluated in its hemostatic and blood saving effects, in patients submitted to myocardial revascularization with extracorporeal circulation. To 40 patients were administered placebo and to 55 tranexamic acid I.V. in a dosage of 10 g in the operative period (2 g in the anesthetic induction and the remaining 8 g in a continuous way during the operative procedure. Tranexamic acid, in this dosage, has proved to have a very impressive hemostatic effect, leadir g to a reduction in post operative bleeding of 47% in 12 h, 42,5% in 24 h and 40,5% when drains were taken off, related to the control group (p < 0.05. Tranexamic acid have led to less utilization for homologous paked red cells per patient, but statistical significance was found only in the 24 h of post operative period, with 1,025 units/patient in control group and 0,333 units/ patient in treated group. Concerning post operative complications, there have been more neurological alterations without sequelae (2.5% against 12.7% and creatinin alterations (5% against 10.9% in the tranexamic acid group. Such alterations were attributed to the high dosage used. As a conclusion, we do not recommend routine use of tranexamic acid to patients submitted to myocardial revascularization in the dosage of 10 g I.V., but, owing to the evident hemostatic effect of the drug, we recommend more investigations concerning the ideal dosage and way of administration.

  12. Influence of zeolite treated with sulphuric acid and sodium hydroxide on the coagulation-flocculation process of drainage. Influencia de la zeolita tratada con acido sulfurico y con hidroxido de sodio en el proceso de coagulacion floculacion en aguas superficiales

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Duque, M.; Herrera Vasconcelos, T.; Laria Piedra, N.

    1994-01-01

    The present paper has had as objective the treatment of natural zeolite from Tasajera with sulfuric acid and sodium hydroxide (residuals acid and basic from the regeneration of cationic and anionic resins of the ''Otto Parallada'' thermoelectric plant) at different times and concentrations, with a further comparison and testing of the effectiveness of the obtained zeolite in respect to the natural one as a coadyuvant of the coagulation-flocculation process in the treatment of superficial water. (Author)

  13. Obtention and characterization of acrylic acid-i-polyethylene organometallic copolymers with Mo, Fe, Co, Zn, and Ni; Obtencion y caracterizacion de copolimeros organometalicos de acido acrilico-i-polietileno, con Mo, Fe, Co, Zn y Ni

    Energy Technology Data Exchange (ETDEWEB)

    Dorantes, G.; Urena, F.; Lopez, R. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Lopez, R. [Universidad Autonoma del Estado de Mexico (Mexico)

    1997-07-01

    In this study a graft acrylic acid (AA) in low density polyethylene (PEBD) copolymers were prepared, using as reaction initiator, gamma radiation at different doses. These copolymers were coordinated with molybdenum, cobalt, iron, zinc and nickel. the obtained polymeric materials were characterized by conventional analysis techniques. It was studied the measurement parameter variation of the positron annihilation when they inter activated with this type of materials and so obtaining information about microstructure of these polymers. (Author)

  14. Exhaust lead-acid batteries recycling as a tool of the environmental protection policy. Energy, environmental and economic issues; Il riciclaggio delle batterie al piombo-acido esauste come strumento della politica di salvaguardia ambiental. Aspetti energetici, ambientali ed economici

    Energy Technology Data Exchange (ETDEWEB)

    Picini, P.; Battista, A. [ENEA, Divisione Caratterizzazione dell' Ambiente e del Territorio, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy)

    2001-07-01

    Lead is an heavy metal that has a major impact on human health and his removal from the environment is an important action for its protection. The aim of the present work is to provide a framework of the Italian lead recycling with respect to the economic and environmental aspects of COBAT activities (COBAT is the Mandatory Consortium to collect and recycle the exhaust lead-acid batteries and lead wastes). In order to better understand the context in which COBAT works, some statistical data on the lead production, consumption and end uses in Italy and in the world are provided. An estimate of the energy consumptions and the environmental impact related to Italian lead production was also carried out. [Italian] Il piombo e' uno dei metalli pesanti a maggiore impatto ambientale e sanitario e la sua rimozione dall'ambiente costituisce un'importante azione di protezione e tutela della salute umana. Lo scopo del presente lavoro e' quello di fornire un quadro di riferimento relativo al riciclaggio del piombo in Italia evidenziandone gli aspetti ambientali ed economici in relazione alle attivita' condotte dal COBAT (Consorzio Obbligatorio delle Batterie Esauste e dei rifiuti piombosi). In tal senso, per disporre di una visione piu' completa del contesto in cui si inserisce l'attivita' del Consorzio, vengono forniti alcuni dati di carattere statistico sulla produzione, sul consumo e sugli utilizzi del piombo in Italia e nel mondo e viene effettuata una stima dei consumi energetici e dell'impianto ambientale associati alla produzione di piombo nazionale.

  15. COMPOSICIÓN MOLECULAR DE ACIDOS HUMICOS EVALUADA MEDIANTE PIRÓLISIS -CROMATOGRAFIA DE GASES- MASAS E HIDRÓLISIS TÉRMICA ASISTIDA Y METILACIÓN, EN SUELOS ALTOANDINOS – COLOMBIA

    Directory of Open Access Journals (Sweden)

    Claudia Martinez

    2014-07-01

    Full Text Available Se determinó la composición  molecular de ácidos húmicos (AH, extraídos del horizonte A de suelos altoandinos, Colombia dedicados a tres usos: bosque primario, cultivo y pastura. Los AH se obtuvieron mediante extracción secuencial de la materia orgánica humificada (MOH con soluciones de tetraborato, pirofosfato e hidróxido de sodio (0,1N, y fueron purificados por diferentes procesos analíticos. Su composición molecular se determinó  por Py-GC/MS y THMA. Los diferentes productos de la pirolisis se clasificaron atendiendo a la familia química a la que pertenecen,  prevalecieron los ácidos grasos (FA como el producto más abundante en los AH de todos los usos, mientras que  los fenoles, esteroles, S-compuestos y terpenos se encontraron en menor abundancia. Se presentaron diferencias en los porcentajes de abundancia relativa de los grupos identificados, demostrando que el cambio de uso de suelo influye en las propiedades físicas, químicas y biológicas del suelo por lo que se perciben diferentes grados de transformación, que afectan la composición de los AH y su reactividad en el suelo.

  16. Relación de la carga ácida de la dieta y el estado acido-base en niños con Enfermedad Renal Crónica

    OpenAIRE

    Lugo, Gustavo; Moreno, Greysi; Marcano, Gilmary; López, Michelle

    2016-01-01

    La progresión de la Enfermedad Renal Crónica (ERC) es acelerada por la acidosis metabólica, la cual puede ser agravada por la dieta. El objetivo del presente trabajo fue determinar la Carga Acida Potencial Renal (CAPR) de la dieta en niños con ERC y establecer su relación con el estado ácido base. MÉTODOS: Se incluyeron 26 pacientes (10 meses-17 años) con ERC atendidos en la consulta del Servicio de Nefrología del Hospital de Niños JM de los Ríos entre Junio 2014 y Enero 2016. Para la evaluac...

  17. Exhaust lead-acid batteries recycling as a tool of the environmental protection policy. Energy, environmental and economic issues; Il riciclaggio delle batterie al piombo-acido esauste come strumento della politica di salvaguardia ambiental. Aspetti energetici, ambientali ed economici

    Energy Technology Data Exchange (ETDEWEB)

    Picini, P; Battista, A [ENEA, Divisione Caratterizzazione dell' Ambiente e del Territorio, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy)

    2001-07-01

    Lead is an heavy metal that has a major impact on human health and his removal from the environment is an important action for its protection. The aim of the present work is to provide a framework of the Italian lead recycling with respect to the economic and environmental aspects of COBAT activities (COBAT is the Mandatory Consortium to collect and recycle the exhaust lead-acid batteries and lead wastes). In order to better understand the context in which COBAT works, some statistical data on the lead production, consumption and end uses in Italy and in the world are provided. An estimate of the energy consumptions and the environmental impact related to Italian lead production was also carried out. [Italian] Il piombo e' uno dei metalli pesanti a maggiore impatto ambientale e sanitario e la sua rimozione dall'ambiente costituisce un'importante azione di protezione e tutela della salute umana. Lo scopo del presente lavoro e' quello di fornire un quadro di riferimento relativo al riciclaggio del piombo in Italia evidenziandone gli aspetti ambientali ed economici in relazione alle attivita' condotte dal COBAT (Consorzio Obbligatorio delle Batterie Esauste e dei rifiuti piombosi). In tal senso, per disporre di una visione piu' completa del contesto in cui si inserisce l'attivita' del Consorzio, vengono forniti alcuni dati di carattere statistico sulla produzione, sul consumo e sugli utilizzi del piombo in Italia e nel mondo e viene effettuata una stima dei consumi energetici e dell'impianto ambientale associati alla produzione di piombo nazionale.

  18. Dosimetric influence of hyaluronic acid in patients with prostate cancer treated with RT3D; Influencia dosimetrica del acido hialuronico en pacientes cancer de prostata tratados con RT3D externa+HDR braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, J.; Vazquez, J. A.; Garcia Blanco, A. S.; Gomez, F.; Montejo, A.; Raba, J. I.; Pacheco, M. T.; Cardenal Carro, J.; Mendigueren, M. A.

    2013-07-01

    This study aims to assess the influence on dosimetry by the introduction of hyaluronic acid and assess the need for the realization of a second CT scan and consequent re-planning of RT3D treatment. (Author)

  19. Un nuevo Método para Mejorar el Proceso de Producción de Acido Bórico A New Method to Improve the Production Process of Boric Acid

    OpenAIRE

    Orlando J Domínguez; Emilio M Serrano; Jorge E Flores; Raquel L Michel

    2011-01-01

    En este trabajo se propone una modificación al proceso tradicional para obtener ácido bórico, con el agregado fraccionado del ácido lixiviante, para lograr un producto altamente soluble, como el pentaborato de sodio. Con esto se consigue la disolución del mineral en frío con menor cantidad de reactivo lixiviante, ahorrando así energía. Al líquido clarificado se le disminuye el pH logrando así la precipitación del ácido bórico. La ganga se agota con diferentes etapas de precipitación y filtrac...

  20. Influence of the temperature in the uranyl sorption in zirconium diphosphate modified with salicylic acid; Influencia de la temperatura en la sorcion de uranilo en difosfato de circonio modificado con acido salicilico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Solis C, D. A. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon y Paseo Tollocan s/n, 50000 Toluca, Estado de Mexico (Mexico); Ordonez R, E., E-mail: nidgg@yahoo.com.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (MX)

    2011-11-15

    In this work the experimental conditions were established to evaluate the uranium (Vi) sorption to 20 and 40 C on the surface of the zirconium diphosphate (ZrP{sub 2}O{sub 7}) modified with a solution of salicylic acid 0.1 M. The modification of the ZrP{sub 2}O{sub 7} was produced during the hydrate process, taking advantage that these are formed complexes between the carboxyl and hydroxyl groups of salicylic acid and amphoteric species of the interface solid/liquid. The method is used by lots to elaborate the isotherms that explain the behavior of this sorption in different ph conditions and temperature, the quantity of the uranium reaction is analyzed with the fluorescence technique. The results indicated that in the temperature increases the uranium sorption on the material and is more efficient to low ph values. (Author)

  1. Shyntesis and cytotoxicity evaluation in vitro of new compounds with hybrid structures of 8-flavoneacetic acid and quinolones; Sintesis y evaluacion citotoxica in vitro de nuevos compuestos con estructuras hibridas del acido 8-flavonacetico quinolonas

    Energy Technology Data Exchange (ETDEWEB)

    Biaa, M F; Castellano, J M; Emling, F; Schlick, E [Knoll, S.a., Madrid (Spain)

    1994-12-31

    Using the structural similarity between 8-flavoneacetic acid the antitumor quinolones, we have prepared some hybrid compounds on both systems and studied their cytotoxicity. None of the sinthesized compounds have shown sufficient interest for further development. 33 refs.

  2. Description and drawing of a mini-plant to lead-acid batteries active material production; Descricao e desenho de uma mini-planta piloto para producao de material ativo para baterias de chumbo-acido

    Energy Technology Data Exchange (ETDEWEB)

    D` Alkaine, C V; Mattos, J S.D.; Machado, D M; Nart, F C [Sao Carlos Univ., SP (Brazil). Dept. de Quimica

    1985-12-31

    As a part of the UFSCAR/Solar Energy/FINEP program, a pilot plant for the production of the active material for lead-acid batteries was developed. The basic operations are: milling and lead oxidation in ball mill, classifying of lead monoxide in the proper particle size by means of a cyclone, monoxide mixture with water and sulphuric acid, thus forming the paste. The paste is then placed on grids and finally scrapped and compacted. The plates pass through a 300 deg C oven and are cured in controlled atmosphere. (author). 4 refs

  3. {sup 1} H and {sup 13} C NMR studies on the enoling of 5-benzyl barbituric acids; Estudos por H-1 e C-13 RMN da enolizacao de acidos 5-benzil barbituricos

    Energy Technology Data Exchange (ETDEWEB)

    Villar, Jose Daniel Figueroa; Santos, Nedina Lucia dos; Cruz, Elizabete Rangel [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Quimica

    1992-12-31

    This work shows that the derivatives of the 5-benzyl barbituric acids hydroxylated at the ortho position of the aromatic ring only exist in the enol form. and that the alkylation of this hydroxyl gives products which exist mainly in the ketone form of the DMSO 5 refs., 2 figs., 2 tabs.

  4. ({sup 1} H, {sup 13} C and {sup 31} P) NMR of phosphonic acid derivatives; Ressonancia magnetica nuclear ({sup 1} H, {sup 13} C, {sup 31} P) de derivados do acido fosfonico

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Valdevino; Costa, Valentim E. Uberti [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Quimica

    1992-12-31

    In the last years the development of phosphates analogues in the medical and agricultural pesticides has being very expressive. {sup 1} H, {sup 13} C and mainly {sup 31} P NMR are used for stereochemical and conformational analysis, and reactivity studies on the compounds resulting from those chemical processes 2 refs., 4 figs., 1 tab.

  5. NMR study of the epoxidation of liquid hydrolyzed poly-butadiene and meta-chloro-per-benzoic acid; Estudo atraves de RMN da reacao de epoxidacao de polibutadieno liquido hidroxilado (PBLH) e acido m-cloro perbenzoico (AMCPB)

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Marcelo [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Akcelrud, L [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica; Menezes, Sonia Cabral de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1994-12-31

    This work presents a study concerning the selectivity of the different configurations of the double bond present in liquid hydrolyzed poly-butadiene towards the epoxidation reaction with meta-chloro-per-benzoic acid through hydrogen-1, carbon-13 NMR aiming the production of new materials, varying the epoxidation level 12 refs., 7 figs., 4 tabs.

  6. Effect of the humic acids in the adsorption of U (Vi) in a Mexican natural zeolite; Efecto de los acidos humicos en la adsorcion de U (VI) en una zeolita natural mexicana

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval G, H. A.; Lopez del R, H.; Davila R, J. I.; Mireles G, F., E-mail: hlopezdelrio@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2012-10-15

    The uranium adsorption was studied in a Mexican natural zeolite of the clinoptilolite type in presence and absence of humic acids (Ha). The adsorption kinetics of the binary U-zeolite and ternary U-Ha-zeolite systems were compared, and the effect of the humic matter impregnated in the zeolite in the uranium removal in function of the solution ph was studied. The experiments were made to environmental conditions and lightly acid ph, with fixed concentrations of uranium and Ha of 1 x 10{sup -5} M and 20 ppm, respectively, and a reason m/V of 5 mg/ml. The uranium adsorption in absence of Ha was of 96% and decreased to 45% in the ternary system U-Ha-zeolite. The data of the binary system U-zeolite were analyzed with three kinetic models of adsorption (pseudo-first order, pseudo-second order and Elovich). By means of non lineal regression was found that the uranium adsorption obeys a kinetic of pseudo-second order. It was observed that the uranium adsorption in the zeolite impregnated with Ha is favored to more ph at 5. (Author)

  7. Modification of zirconium diphosphate with salicylic acid and its effect on the uranium (Vi) sorption; Modificacion del difosfato de circonio con acido salicilico y su efecto sobre la sorcion de uranio (VI)

    Energy Technology Data Exchange (ETDEWEB)

    Almazan T, M. G.; Garcia G, N. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Simoni, E., E-mail: guadalupe.almazan@inin.gob.mx [Universidad Paris Sud, Instituto de Fisica Nuclear, Georges Clemenceau No. 15, Orsay (France)

    2014-10-15

    The surface of zirconium diphosphate (ZrP{sub 2}O{sub 7}) was modified with salicylic acid and its effect was evaluated on the uranium (Vi) sorption. The modified surface of the material was analyzed with different analytical techniques among which are included the atomic force microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. This analysis allowed showing that the salicylic acid is being held on the surface of the zirconium diphosphate. The reactivity of modified zirconium diphosphate compared with uranium (Vi) was investigated using the classical method of batch sorption. The analysis of sorption isotherms shows that the salicylic acid has an important effect in the uranium (Vi) sorption. According to the study conducted, the interaction among the uranium (Vi) and the surface of zirconium diphosphate modified with the salicylic acid most likely leads to the complexes formation of binary (U(Vi)/ZrP{sub 2}O{sub 7}) and ternary (U(Vi)/salicylate/ZrP{sub 2}O{sub 7}) surface. (Author)

  8. Bioethanol production by cashew apple bagasse (Anacardium occidentale L.): comparison of acid diluted and alkali pre-treatments; Producao de bioetanol a partir da fibra do caju (Anacardium occidentale L.): comparacao entre o pre-tratamento acido e alcalino

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Tigressa H.S.; Pinheiro, Alvaro D.T.; Goncalves, Luciana R.B. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Rocha, Maria V.P.; Macedo, Gorete R. de [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    Due to the growing environmental awareness on the negative impact resulting from utilization of fossil fuels, and in the search for renewable energy sources, biofuels' interest as Bioethanol has rapidly expanded recently. In this context, lignocellulosic compounds have become center of attention as an abundant and economic alternative source of carbohydrates for ethanol production. In this study, cashew's bagasse acid hydrolysis was initially studied for glucose synthesis and its fermentation towards ethanol production. Sulfuric acid concentration, solids concentration and time were some of the factors evaluated. The highest glucose productivity value (162,9 mg.g de bagaco{sup -1}) , was obtained for 0,6 mol.L{sup -1} of sulfuric acid in an autoclave at 121 deg C for 15 min. For the fermentation of the hydrolyzed material by S. cerevisiae containing 16 {+-} 2,0 g.L{sup -1} of glucose metabolic, the yield and productivity obtained were 0,63 g-g glucose{sup -1} and 1,43 g.L{sup -1}h{sup -1} respectively. Ethanol concentration after 6 h of fermentation of this hydrolyzed was 11 g.L{sup -1}. In the best conditions of acid hydrolysis, a second pre-treatment with diluted sulfuric acid was performed to evaluate availability of hemicelluloses at 160 deg C and 180 deg C. For comparative purposes, alkali pre-treatment was evaluated under the conditions of 0,6 mol.L{sup -1}, 30% p/v of bagasse thermically treated at 121 deg C for 15 minutes. However, concentration of sugars was not sufficient for fermentation. Also, nitrogen supplementation of the hydrolyzed fraction did not influence significantly ethanol production. The results demonstrate that the hydrolyzed fraction from the acid pre-treatment of cashew's bagasse could be utilized for ethanol production. (author)

  9. Study of stability of humic acids from soil and peat irradiated by gamma rays; Estudo da estabilidade de acidos humicos extraidos de solo e turfa, frente a radiacao ionizante gama

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Wilson Tadeu Lopes da

    1995-07-01

    Humic acids samples (one deriving from a sedimentary soil and other from a peat), in aqueous media, were irradiated with gamma rays, in doses of 10, 50 and 100 kGy, in order to understand their chemical behavior after the irradiation. The material, before and after irradiation, was analyzed by Elemental Analysis, Functional Groups (carboxylic acids and phenols), UV/Vis Spectroscopy (E{sub 4}/E{sub 6} ratio), IR spectroscopy, CO{sub 2} content and Gel permeation Chromatography (GPC) ). The Elemental Analysis showed the humic acid derived from a peat had a most percentage quantity of Carbon and Hydrogen than the material from a sedimentary soil. From the UV/Vis Spectroscopy, it was observed a decrease of E{sub 4}/E{sub 6} ratio with an increase of the applied dose. The data from GPC are in agreement with this. The results showed that the molecular weight of the material increased by exposing it to a larger radiolitical dose. The peat material was less affected by the gamma radiation than the soil material. The carboxylic groups were responsible by radiochemical behavior of the material. (author)

  10. Combustion synthesis by reaction and characterization of nano ferrites: study of fuel aniline, citric and its mixture; Sintese por reacao de combustao e caracterizacao de nanoferritas Ni-Zn: estudo dos combustiveis anilina, acido citrico e sua mistura

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.C. da; Coutinho, J.P.; Costa, A.C.F.M., E-mail: normanda@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais; Freitas, N.L. de [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Tecnologia do Desenvolvimento

    2012-07-01

    The present study aims to evaluate the influence of aniline and citric acid used alone and combined in a ratio of 50% each in the characterization of NiZn ferrite synthesized by combustion reaction method in a muffle furnace. Measurements were made of temperature and reaction time. The nano-powders were characterized by XRD, EDX, textural analysis and SEM. The highest temperature was achieved by the reaction using the mixture of fuel and increased reaction time using citric acid. The nano ferrites using different fuels, and the mixture changed phases, the crystallite size and decreased surface area of the samples with aniline, citric acid and a mixture of both, respectively. The powder morphology ranged from presenting the formation of irregular blocks for the use of citric agglomerated in the form of skeins with aniline and a mixture to agglomerate larger particles. (author)

  11. Influence of reason citric acid/ metal cations in the synthesis of mullite by Pechini Method; Iinfluencia da razao acido citrico/cations metalicos na sintese de mulita pelo Metodo Pechini

    Energy Technology Data Exchange (ETDEWEB)

    Braga, A.N.S.; Costa, D.L.; Farias, R.M.C.; Neves, G.A.; Lira, H.L.; Menezes, R.R., E-mail: Alluskynha@homail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais

    2014-07-01

    Mullite is a ceramic material with high technological applications. Its synthesis has been extensively studied due to their excellent properties. Thus, this paper proposes to obtain mullite by Pechini method. The amount of acid citric/metal cations in proportions of 3:1 and 1:1 were investigated in order to understand their influence in obtaining the mullite phase. The synthesized samples were characterized by X-ray diffraction (XRD) and thermal analysis (TG/DTG and DTA). The results showed that the ratio citric acid/metal cations influence on the formed phase with the mullite obtained only in proportion 1:1. With the increase of the ratio to 3:1 was observed the formation of the alumina layer. (author)

  12. Influence of several nonferrous metals in the treatment of residual liquors from hydrochloric acid pickling processes. Influencia de diversos metales no ferreos en el tratamiento de lejias residuales de decapado con acido clorhidrico

    Energy Technology Data Exchange (ETDEWEB)

    Negro, C.; Cobos, M.A.; Latorre, R.; Dufour, J.; Formoso, A.; Lopez, F.

    1994-01-01

    In the oxiprecipitation of waste liquors from siderurgical processes of pickling with hydrochloric acid, several kinds of iron oxides and oxihydroxides are obtained: alpha-FeOOH, gamma-FeOOH, Fe[sub 3]O[sub 4], gamma-Fe[sub 2]O[sub 3]. Fe[sub 2]O[sub 3].1,2H[sub 2]O, etc. These products can be used like pigments in the painting industry and like raw materials for the obtaining of ferrites. Varying the operation conditions, the presence of these products can be changed greatly, obtaining different mixtures of them. The presence of non-ferrous metals catalyzes and modifies the mechanism of the reaction, yielding pure products. This simplifies their later industrial applications. The aim of this work is to determine the influence of Cu(II), Zn(II), Mo(VI) and Al(III) on the oxiprecipitation of residual liquors from hydrochloric acid pickling processes, selecting the most favourable operation conditions at which it is possible to obtain products for industrial applications.

  13. Synthesis and reactions with a midines of derivates cycles and of open chain of 2-bromo-3, 4-dioxobutanoic; Sintesis y reacciones con amidinas de derivados ciclicos y de cadena abierta del acido 2-bromo-3, 4-dioxobutanoico

    Energy Technology Data Exchange (ETDEWEB)

    Ancos, B. de; Delgado, F.; Martin, M.R. [Departamento de Quimica Organica, Facultad de Ciencias, Universidad Autonoma, Madrid (Spain)

    1995-12-31

    Bromination of enaminoesters 1 and 5, in appropriate conditions, affords in good yield enamines of the corresponding 2-bromo-3.4-dioxobutanoic acid derivatives 2-3 and 6 or dibromocompounds 4 and 6. The open chain enaminoesters (1-3) are more easily hydrolyzed that enaminofuranones 5 and 6. Prolongated treatment of 6 with hydrochloric acid affords the chlorinated enamine 11. The synthesis of 3-Bromo-4-hydroxy-5-methoxyfuran-2(5H)-one 10 can be achieved by bromination of 12, obtained by hydrolysis of 5. The reaction of methyl 3-bromo-4, 4-dimethoxy-3-oxobutanoate with amidines is a good method for the synthesis of 5-bromo-6-(dimethoxymethyl) pyrimidine-4(3H)-ones substituted at 2 position. Under the same conditions the reaction of furanone 10 with benzamide does not lead to the corresponding imidazoline. (Author) 12 refs.

  14. Influence of zeolite treated with sulphuric acid and sodium hydroxide on the coagulation-flocculation process of drainage. Influencia de la zeolita tratada con acido sulfurico y con hidroxido de sodio en el proceso de coagulacion floculacion en aguas superficiales

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez Duque, M; Herrera Vasconcelos, T; Laria Piedra, N

    1994-01-01

    The present paper has had as objective the treatment of natural zeolite from Tasajera with sulfuric acid and sodium hydroxide (residuals acid and basic from the regeneration of cationic and anionic resins of the ''Otto Parallada'' thermoelectric plant) at different times and concentrations, with a further comparison and testing of the effectiveness of the obtained zeolite in respect to the natural one as a coadyuvant of the coagulation-flocculation process in the treatment of superficial water. (Author)

  15. Effect of glycerin and formic acid in the efficiency of deposit on Zn-Ni, obtained by electrodeposition; Efeito da glicerina e do acido formico na eficiencia de deposito da liga Zn-Ni, obtido atraves de eletrodeposicao

    Energy Technology Data Exchange (ETDEWEB)

    Pedroza, G.A.G.; Souza, C.A.C.; Lima, L.R.P.A.; Ferreira, D.M. [Universidade Federal da Bahia - Escola Politecnica, BA (Brazil)

    2010-07-01

    Additives are added to the electrodeposition of metal coatings to improve the characteristics of the deposit. However, the objective was to investigate the effect of adding glycerin and formic acid in the deposition efficiency and deposit structure of zinc-nickel alloy obtained by electrodeposition. The depositions were made at a galvanostatic current density of 10 mA/cm{sup 2} to obtain a deposit of about 5 mm in thickness. The deposition efficiency was determined through measures of mass, chemical composition of the deposit in the presence and absence of additives was examined by X-ray Spectrometer Fluorescence (XRF) and surface characterization of coatings was performed by Scanning Electron Microscopy (SEM). The high levels of glycerin (0,07 M) and formic acid (0,26 M) in bath deposition increased the deposition efficiency of around 10% to 12% by mass, respectively. (author)

  16. Influence of citric acid as setting retarder in CPV portland cement pastes and mortars; Influencia do acido citrico como retardador de pega em pastas e argamassas de cimento portland CPV ARI

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, B.C.; Lopes, M.M.S.; Alvarenga, R.C.S.S.; Fassoni, D.P.; Pedroti, L.G. [Universidade Federal de Vicosa (UFV), MG (Brazil); Azevedo, A.R.G. de, E-mail: afonso.garcez91@gmail.com [Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ (Brazil)

    2016-07-01

    This work aims to study the availability of using and the influence of citric acid in the properties of pastes and mortars made with Portland cement CPV ARI both in fresh and hardened form. The citric acid dosages were 0, 0.4%, and 0.8% relative to the cement mass. The produced cement pastes were tested to determine normal consistency water and initial and final setting times. Mortars were tested to determine the consistency index, specific gravity, air entrained content in the fresh stage, hardened bulk density, compressive strength at ages 7, 14, and 28 days, and analysis by XRD technique. The results show that citric acid, besides improve the mortar workability, contribute to an increase in mechanical strength in older than 14 days. (author)

  17. Preparation and characterization of a composite based on Zr(IV) and phosphoric acid; Preparacao e caracterizacao de um composito a base de Zr(IV) e acido fosforico

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, T.F.S. da; Carmo, D.R. do, E-mail: taylafserantoni@gmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Faculdade de Engenharia. Departamento de Fisica e Quimica

    2014-07-01

    The present work describes the preparation and characterization of a composite formed from zirconium (IV) isopropoxide and phosphoric acid (ZrP). This composite (ZrP) was characterized by techniques such as infrared spectroscopy (FTIR), {sup 13}C and {sup 31}P nuclear magnetic resonance (NMR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and thermogravimetric analysis (TG). Vibrational spectrum for ZrP showed a band at ∼ 1010 cm{sup -1} assigned to the stretching P=O(νP=O). The results obtained by EDS confirmed the presence of elements Zr, P and O in the formed composite, and any C has been detected in concordance of NMR of {sup 13}C. The {sup 31}P NMR spectrum of ZrP showed two pronounced peaks characteristic of zirconium phosphate. In the TG curve three steps of weight loss were observed for ZrP. (author)

  18. Effect of organoclays content and modify the impact on mechanical properties of of bionanocomposites poly (lactic acid ) - PLA; Efeito do teor de argilas organofilicas e modificador de impacto nas propriedades mecanicas de bionanocompositos de poli (acido latico)-PLA

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcanti, Shirley N.; Alves, Amanda M.; Agrawal, Pankaj; Silva, Moacy P. da; Araujo, Aylanna P.M.; Araujo, Edcleide M.; Melo, Tomas J.A., E-mail: shirleynobre@gmail.com [Universidade Federal de Campina Grande (UFCG), Campina Grande, PB (Brazil). Departamento de Engenharia de Materiais

    2015-07-01

    Until recently, it has become important to develop more durable plastic materials to meet the needs of the market, which have wide range of applications. But these materials are from non-renewable sources cause environmental impact due to the large amount of waste they produce. In order to evaluate the effect of organoclay (Brasgel PA and vermiculite) and impact modifier (EMA-GMA) were developed PLA bionanocomposites / Clays through the merge process by melting and rated the content (1, 3 and 5pcr) the mechanical properties of these clays. The clays were organophilizated using a percentage of surfactant based on the capacity of cation exchange. The bionanocomposites were prepared by extrusion followed the injection molding step of the specimens. The clays were characterized by X-ray diffraction (XRD).The bionanocomposites were characterized by the mechanical properties of impact and traction. The techniques of X-ray diffraction showed that organophilization process used was efficient. The mechanical properties were changed, and the impact strength showed considerable gain when the PLA was blended with the copolymer and the organoclay. (author)

  19. Characterization of commercial ceramic adsorbents and their application on naphthenic acids removal of petroleum distillates; Caracterizacao de adsorventes ceramicos comerciais e sua aplicacao na remocao de acidos naftenicos de destilados de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, J.P.; Senna, L.F. de; Lago, D.C.B. do; Silva Junior, P.F. da; Figueiredo, M.A.G. de; Dias, E.G. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)], e-mail: julia_psi@yahoo.com.br; Chiaro, S.S.X. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2006-07-01

    One denominates 'naphthenic acids' to the mixture of carboxylic acids that is present in petroleum oil, and is directly responsible for its acidity and corrosiveness in liquid phase during the refine process. These acids are also presents in distilled fraction of petroleum, causing several problems in final products quality. A possible way to remove them from petroleum distilled fractions is the adsorption in porous materials. However, the published results indicate that ion exchange resins would be the best adsorbents for this process, which would probably increase its cost. In this work, two commercial adsorbents (clay and activated alumina) were characterized by a set of physical-chemistry techniques and evaluated concerning their capacity of removing naphthenic acids from a light petroleum fraction. It was also verified the influence of a previous thermal treatment to the adsorption in their physical-chemistry characteristics and its properties. (author)

  20. Preparation and characterization of sulfated zirconia acid catalysts for application in the esterification of cottonseed oil; Preparacao e caracterizacao de catalisadores acidos de zirconia sulfatada para aplicacao na esterificacao do oleo de algodao

    Energy Technology Data Exchange (ETDEWEB)

    Silva, F. N.; Moura, T. F. B.; Silva, A.S.; Costa, A.C.F.M., E-mail: fnilson.s@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Pos-graduacao em Engenharia de Materiais; Pallone, E.M.J.A. [Universidade de Sao Paulo (USP), Pirassununga, SP (Brazil). Dept. de Ciencias Basicas

    2017-07-15

    This work aimed to produce zirconia by combustion synthesis, to analyze the structure and morphology comparatively with a commercial monoclinic ZrO{sub 2} , as well as, to investigate the sulfation, aiming to obtain acid catalysts for its use in the esterification of cotton oil for biodiesel. The samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), specific surface area by BET method, infrared spectroscopy (FTIR), thermal analysis (TG/DrTG/DTA), granulometric distribution, pH and chromatography. The synthesized sample evidenced the formation of the monoclinic phase with traces of the orthorhombic phase, while in the commercial sample only the monoclinic phase was observed. In the sulfation process, traces of the tetragonal phase, typical of sulfated zirconia, were observed with the presence of the monoclinic phase in the two samples. With the impregnation of the sulfate ion on the surface of the samples, an increase in the particle size was observed, as seen in the characterization of BET, granulometric distribution and SEM, which also indicated a homogeneous morphology consisting of fine particles of approximately spherical shape for both samples. The chromatography indicated conversion of 65.5 and 91.8% in methyl esters to the synthesized and commercial SO{sub 4} {sup 2-}/ZrO{sub 2} , respectively. The results indicated that the sulfation increased the acidity, which was evidenced by the decrease in the pH, ranging from 5.12 to 2.65, which contributed significantly to the increase of the conversion, indicating that the SO{sub 4} {sup 2-}/ZrO{sub 2} is a promising catalyst in the esterification. (author)

  1. Evaluation of the physicochemical properties of structured materials: metallic, polymeric and ceramic, for the treatment of sour gases; Evaluacion de las propiedades fisicoquimicas de materiales estructurados: metalico, polimerico y ceramico, para el tratamiento de gases acidos

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, A.; Chavez, R. H. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Olea, O.; Solis, D., E-mail: rosahilda.chavez@inin.gob.mx [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Cerro de Coatepec s/n, Ciudad Universitaria, 50100 Toluca, Estado de Mexico (Mexico)

    2013-07-01

    in this work the physicochemical properties of three structured materials: metallic, polymeric and ceramic, from Sulzer Brothers Limited brand, are studied in order to removal sour gases, by absorption process, in aqueous solution of Monoethanolamine (Mea), at 30% weight. Mechanical properties, chemical composition, morphology and corrosion resistance were determined, using different characterization techniques, such as: 1) mechanically, according to standard procedures Astm E-384-1990, 2) chemically, by the corrosion resistance in the presence of an electrochemical cell, in aqueous solution of H{sub 2}SO{sub 4}, 1 N by Astm G-5-1999, 3) morphologically by scanning electron microscopy technique, and 4) efficiency of separation, by the gas chromatography technique in order to determine the chemical absorption of CO{sub 2} by Mea. The ceramic material was the hardest with 700 Hk value and tensile strength of 90 MPa, likewise showed resistance to corrosion of 10.28 m py, separation efficiency of 74% CO{sub 2}, at 10 minutes. The metallic material had a hardness of 190 Hk and it was the most resistant of tension, with 831 MPa, and corrosion resistance of 780.4 x 10{sup -6} m py, likewise promoted CO{sub 2} separation efficiency of 90% during the evaluation. The polymeric material presented hardness of 20 Hk and 35 MPa and it was not suffered surface change with electrochemical attack, with 282.4 x 10{sup -6} m py, and separation efficiency of 88%. Therefore the polymer was the most ductile, with smooth surface and greater resistance with H{sub 2}SO{sub 4}. The metal material was more resistant to plastic deformation and more corrugated surface and the second resistance in the presence of acid medium in aqueous solutions. For all the above, the metallic material is recommended by its greater separation in the reduction of acid gases and the polymer due to its greater chemical resistance. (Author)

  2. Phosphorus in chronosequence of burnt sugar cane in Brazilian cerrado: humic acid analysis by {sup 31}P NMR; Fosforo em cronossequencia de cana-de-acucar queimada no cerrado goiano: analise de acidos humicos por RMN de {sup 31}P

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Celeste Q.; Pereira, Marcos G.; Garcia, Andreas C., E-mail: mgervasiopereira@gmail.com [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil). Dept. de Solos; Perin, Adriano; Gazolla, Paulo R. [Instituto Federal de Educacao, Ciencia e Tecnologia Goiano, Rio Verde, GO (Brazil); Gonzalez, Antonio P. [Universidade de Coruna, ES (Spain). Faculdad de Ciencias

    2013-10-01

    The aim of this study was to identify, with the use of {sup 31}P NMR spectroscopy, organic P species in humic acids (HA) in samples from Oxisol cultivated in chronosequence with sugar cane, pasture and Cerrado. The main forms of P-type found were orthophosphate, monoester-P (phosphate sugars) and P-diester (orthophosphate). The {sup 31}P NMR technique proved capable of identifying changes in the areas studied as a function of sugar cane burning time. In areas with 1 and 5 years of burnt cane, a decrease in recalcitrant organic P in humic acids indicated the need for use of P-humic substances for plant nutrition (author)

  3. Synthesis and characterization of chitosan-graft-poly(acrylic acid)/rice husk ash hydrogels composites; Sintese e caracterizacao de hidrogeis compositos de cinza da casca de arroz e quitosana enxertada com poli(acido acrilico)

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Francisco H.A. [Universidade Estadual Vale do Acarau - UVA, Sobral, CE (Brazil); Lopes, Gabriel V.; Pereira, Antonio G.B.; Fajardo, Andre R.; Muniz, Edvani C. [Universidade Estadual de Maringa - UEM, PR (Brazil)

    2011-07-01

    According to environmental concerns, super absorbent hydrogel composites were synthesized based on rice husk ash (RHA), an industrial waste, and Chitosan-graft-poly(acrylic acid). The WAXS and FTIR data confirmed the syntheses of hydrogel composites. The effect of crystalline or amorphous RHA on water uptake was investigated. It was found that the RHA in crystalline form induces higher water capacity (W{sub eq}) of composites hydrogels due to the fact that the intra-interactions among silanol groups on RHA make available new sites in the polymer matrix, which could interact to water. (author)

  4. Evaluation of human dental loss caused by carbamide peroxide bleacher compared with phosphoric acid conditioning - radioactive method; Avaliacao da perda dental humana com o uso do clareador peroxido de carbamida comparado ao condicionamento com acido fosforico - metodo radiometrico

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Eduardo Makoto; Yousseff, Michel Nicolau [Sao Paulo Univ., SP (Brazil). Faculdade de Odontologia. Dept. de Dentistica; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica

    2002-07-01

    The radiometric method was applied to the evaluation of dental loss caused by carbamide peroxide when it is applied on the surface layers of enamel and dentin tissues. Also the dental loss caused by the etching with 37% phosphoric acid procedure used in aesthetic restoration was assessed for comparison with those results obtained. The tooth samples irradiated with a P standard in a thermal neutron flux of the nuclear reactor were placed in contact with 10% carbamide peroxide or with 37% phosphoric acid solution. The radioactivity of {sup 32} P transferred from the radioactive teeth to the bleaching gel or to etching acid was measured using a Geiger Muller detector to calculate the mass of P removed in this treatment and losses were calculated after obtaining their P concentrations. Results obtained indicated that enamel and dentin exposed to carbamide peroxide bleaching agent lose phosphorus. The extent of enamel loss was smaller than that obtained for dentin. In the case of acid etching, there was no difference between the results obtained for enamel and dentin loss. Also the dentin loss obtained after a treatment of 30 applications of 10% carbamide peroxide was the same magnitude of that one application of 37% phosphoric acid. (author)

  5. Preparation of polymer blends from glycerol, fumaric acid and of poly(ethylene terephthalate) (PET) recycled; Preparacao de blendas polimericas a partir do glicerol, acido fumarico e do politereftalato de etileno (PET) pos consumo

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Marina A.O.; Guimaraes, Danilo H.; Brioude, Michel M.; Jose, Nadia M. [Instituto de Quimica, Universidade Federal da Bahia, Salvador, BA (Brazil); Prado, Luis A.S. de A. [Institut fuer Kunststoffe und Verbundwerkstoffe - Technische Universitaet Hamburg-Harburg, Hamburg (Germany)

    2011-07-01

    Polymer blends based on recycled poly(ethylene terephthalate) (PET) and poly(glycerol fumarate) polyesters were prepared in different PET concentrations. The PET powder was dispersed during the poly(glycerol fumarate) synthesis at 260 deg C. The resulting blends were characterized by X-ray diffraction. The thermal stability of the materials was evaluated by thermogravimetric analysis and differential scanning calorimetry. The morphology was studies by scanning electron microscopy. The blends were clearly immiscible. The possibility of (interfacial) compatibilization of the PET domains, caused by transesterification reactions between PET and glycerol were discussed. (author)

  6. Preparation and characterization of polymer blends based on recycled PET and polyester derived by terephthalic acid; Preparacao e caracterizacao de blendas polimericas a base de PET reciclado e poliester derivado do acido tereftalico

    Energy Technology Data Exchange (ETDEWEB)

    Ohara, L.; Miranda, C.S.; Fiuza, R.P.; Luporini, S.; Carvalho, R.F.; Jose, N.M., E-mail: leandro.ohara@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais

    2010-07-01

    Environmentally friendly materials, made from industrial waste, are being increasingly used as a solution to the growing amount of waste generated by society, but also as a cheaper alternative to replace conventional materials for use in construction. In this work were investigated the properties of polymer blends based on recycled PET and a polyester derived from terephthalic acid and glycerin, a co-product of biodiesel. The samples were characterized by XRD, TGA, DSC, FTIR and SEM. The polyester synthesized showed a degradation event near 300 deg C. The blends with higher ratio of PET showed thermal behavior similar to pure PET. The X-ray diffraction showed that the polymer blends are semicrystalline materials. The micrographs presents the presence of a smooth surface, indicating the possibility of miscibility between the arrays. Therefore, the blending makes possible the fabrication of low-cost materials with applications in several areas. (author)

  7. Polymeric blends from post-consumer PET and polyester becoming of glycerol and phthalic acid; Misturas polimericas a partir do PET pos-consumo e poliesteres derivados do gliceraol e acido ftalico

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, C.S.; Brioude, M.; Fiuza, R.P.; Luporini, S.; Carvalho, R.F.; Jose, N.M., E-mail: cleidienesm@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais

    2010-07-01

    Preparation of physical mixture or polymer blends is a very important method to obtain a final product with excellent balance of properties, where one component can compensate for the poor property of another, and is often a modified low cost compared to development and synthesis of a new polymer. PET has become a major waste of post-consumer plastics and aiming to remedy this problem, this work aims to obtain blends from recycled PET and polyesters derived from glycerol and phthalic acid. The material with higher proportion of PET showed better thermal properties, observed by TGA and DSC, with a similar profile of pure PET. In XRD analysis showed a semicrystalline, while the SEM is a smooth surface on all materials, characteristic of pure polyester. The ratio of 50% its surface showed a probable immiscibility of polymers. (author)

  8. The elution of erbium from a cation exchanger bed by means of the N-hydroxyethyl-ethylene-diamine triacetic acid; Mecanismo de la elucion del erbio en un cambiador cationico con el acido n-hidroxietil-etilen-diamono-triacetico

    Energy Technology Data Exchange (ETDEWEB)

    Amer Amezaga, S

    1963-07-01

    A physicochemical study of the phenomena resulting when erbium is eluted from a cation-exchanger bed at a steady by means of the N-hydroxyethyl-ethylene-diamine-triacetic acid (HEDTA) is made. Two different retaining beds are used, a hydrogen bed, in which no ammonium passes through, and a zinc bed, which leaks ammonium ion. Good agreement between experimental and calculated values by using the equations deduced for the concentrations of the main species has been achieved, with errors around 1-2% in most of the experiments. (Author) 69 refs.

  9. Cyclopentenyl acids from sapucainha (Carpotroche brasiliensis Endl, Flacourtiaceae): the first antileprotic used in Brazil; Acidos ciclopentenicos do oleo da sapucainha (Carpotroche brasiliensis Endl, Flacourtiaceae): o primeiro antileprotico usado no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Adriana S.; Lima, Joselia A.; Rezende, Claudia M.; Pinto, Angelo C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Tecnologia. Inst. de Quimica]. E-mail: crezende@iq.ufrj.br

    2009-07-01

    The chaoolmugra oil is one of the oldest medicines used for leprosy until the development of sulfas. In Brazil, it is known as sapucainha oil that is obtained from Carpotroche brasilienesis seeds (Flacourtiaceae). Chemical and medicinal studies of sapucainha oil were introduced in Brazil by Peckolt, Cole and Cardoso which showed that major ciclopentenyl fatty acids as chaulmoogric, hydnocarpic and gorlic were responsible for its bactericidal activity. In this work, a method for quantification of sapucainha oil acidic fraction by HRGC was established using methyl n-heptadecanoate as internal standard. The oil chemical stability was investigated by the use of GC-MS, IR, {sup 1}H and {sup 13}C NMR and showed that the main degradation products belong to the cyclopentenyl moiety oxidation. (author)

  10. Phosphategypsum wastes in Venice lagoon. Radiological impact; Le discariche di fosfogessi nella laguna di Venezia. Valutazioni preliminari dell'impatto radiologico

    Energy Technology Data Exchange (ETDEWEB)

    Belli, M; Blasi, M; Guogang, J.; Rosamilia, S.; Sansone, U. [Agenzia Nazionale per la Protezione dell' Ambiente, Rome (Italy); Biancotto, R.; Bidoli, P.; Sepulcri, D. [Agenzia Regionale di Prevenzione e Protezione del Veneto, Venice (Italy). Dipt. provinciale di Venezia; Cavolo, F. [Smilax, Mira, VE (Italy)

    2000-07-01

    The phosphoric minerals utilized in phosphoric acid production, presents high concentrations of radioactive materials: U238, Th 232, K 40. The phosphogypsum is the waste material obtained in the phosphoric acid production in wet process. This type of production method is employed for many years in Venice lagoon (Porto Marghera chemical plants). In this paper are reported evaluations of radiological impact on aquatic environment of lagoon. [Italian] Con il termine di fosfogessi si intende comunemente il materiale di risulta che si ottiene nella produzione di acido fosforico attraverso la via umida (attacco acido). Questa tipologia di produzione che ha operato per diversi decenni a Porto Marghera, e' finalizzata allo scopo di ottenere acido fosforico principalmente per l'industria dei fertilizzanti e quindi come prodotto intermedio per la chimica e per le preparazioni alimentari. Il fosforo, elemento principale della reazione, era ricavato da rocce fosfatiche di origine sedimentaria marina provenienti per lo piu' dall'Africa settentrionale. Il sistema produttivo utilizzato negli impianti di Porto Marghera era basato su una reazione principale, che partendo dal minerale attraverso un attacco acido, produceva acido fosforico: Ca{sub 3}(PO{sub 4}){sub 2} (Minerale Fosforico) + 3H{sub 2}SO{sub 4} (Acido Solforico) + 3H{sub 2}O (Acqua) {yields} 2H{sub 3}PO{sub 4} (Acido fosforico) + 3CaSO{sub 4}H{sub 2}O (Solfato di calcio (gesso)). In particolare il minerale era preventivamente macinato e vagliato, quindi si procedeva alla sua miscelazione con l'acido fosforico ed alla successiva reazione del composto ottenuto.

  11. FOOD SAFETY AND QUALITY IN DEVELOPING COUNTRIES: THE ROLE OF LACTIC ACID BACTERIA

    OpenAIRE

    ANGRI, MATTEO

    2016-01-01

    La sicurezza e la qualità degli alimenti sono tutt’ora un problema critico per i paesi in via di sviluppo. Le diete a basso contenuto di acido folico, per esempio, possono causare gravi problemi di salute, soprattutto nei bambini. Gravi disturbi legati al tubo neurale (DTN) nei neonati possono derivare infatti da madri che hanno insufficiente apporto di acido folico (400-600 g / giorno) durante il periodo di gravidanza. Inoltre, se non adeguatamente protetti o trattati, I prodotti alimentari ...

  12. A comparison of exogenous and endogenous CEST MRI methods for evaluating in vivo pH.

    Science.gov (United States)

    Lindeman, Leila R; Randtke, Edward A; High, Rachel A; Jones, Kyle M; Howison, Christine M; Pagel, Mark D

    2018-05-01

    Extracellular pH (pHe) is an important biomarker for cancer cell metabolism. Acido-chemical exchange saturation transfer (CEST) MRI uses the contrast agent iopamidol to create spatial maps of pHe. Measurements of amide proton transfer exchange rates (k ex ) from endogenous CEST MRI were compared to pHe measurements by exogenous acido-CEST MRI to determine whether endogenous k ex could be used as a proxy for pHe measurements. Spatial maps of pHe and k ex were obtained using exogenous acidoCEST MRI and an endogenous CEST MRI analyzed with the omega plot method, respectively, to evaluate mouse kidney, a flank tumor model, and a spontaneous lung tumor model. The pHe and k ex results were evaluated using pixelwise comparisons. The k ex values obtained from endogenous CEST measurements did not correlate with the pHe results from exogenous CEST measurements. The k ex measurements were limited to fewer pixels and had a limited dynamic range relative to pHe measurements. Measurements of k ex with endogenous CEST MRI cannot substitute for pHe measurements with acidoCEST MRI. Whereas endogenous CEST MRI may still have good utility for evaluating some specific pathologies, exogenous acido-CEST MRI is more appropriate when evaluating pathologies based on pHe values. Magn Reson Med 79:2766-2772, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  13. Study of the temperature influence during the uranium (Vi) sorption on surface of ZrP{sub 2}O{sub 7} in presence of oxalic and salicylic acid; Estudio de la influencia de la temperatura durante la sorcion de uranio (VI) en la superficie del ZrP{sub 2}O{sub 7} en presencia de acidos oxalico y salicilico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.

    2013-07-01

    This work studies the effect of temperature on the uranium (Vi) sorption onto zirconium diphosphate in the presence of organic acids (oxalic and salicylic acids). Zirconium diphosphate was synthesized by a chemical condensation reaction and characterized using several analytical techniques, in order to check its purity. This point is very important because the presence of any impurities or secondary phases may interfere with the hydration and sorption process. Prior to the sorption experiments, three batches of zirconium diphosphate were pre-equilibrated with NaClO{sub 4}, oxalic acid or salicylic acid solutions. The hydrated solids were washed and dried and then again characterized in order to study the interactions between organic acids and zirconium diphosphate surface. Uranium sorption onto zirconium diphosphate (pre-equilibrated with NaClO{sub 4}, oxalic acid and salicylic acid solutions) was investigated as a function of ph, organic acid and temperature (20, 40 y 60 grades C). Thermodynamic parameters for the sorption reactions (enthalpy change, entropy change and Gibbs free energy change) were determined from temperature dependence of distribution coefficient by using the Vant Hoff equation. Solids characterization after hydration shows that exist an interaction between organic acids and ZrP{sub 2}O{sub 7}. This fact was confirmed with the microcalorimetry study, the reaction heat for hydration of zirconium diphosphate in NaClO{sub 4} solution was exothermic (-269.59 mJ) and for hydration of zirconium diphosphate in oxalic acid solution was endothermic (53.64 mJ). The experimental results showed important differences in the sorption mechanisms for the reaction of Uranium with ZrP{sub 2}O{sub 7} in the presence and absence of organic acids. For the zirconium diphosphate hydrated with oxalic acid, the sorption percentage was 50% from lowest ph values. For the zirconium diphosphate hydrated with salicylic acid, the initial concentration of uranium was 6 x 10{sup -4} M and a percentage of 10% was observed in the initial reaction and it reached 100% at ph 5.5. A similar behavior was observed for the zirconium diphosphate hydrated with NaClO{sub 4}, but the initial concentration of uranium was 5 x 10{sup -4} M. The temperature had an important effect on the sorption of uranium onto ZrP{sub 2}O{sub 7}. The reaction of uranium with the solid hydrated with NaClO{sub 4} was exothermic from 20 to 60 grades C, and the reaction with the solid hydrated with organic acids was exothermic from 20 to 40 grades C and endothermic from 40 to 60 grades C. In conclusion, the thermodynamic study indicated that the sorption process was activated chemisorption s. (Author)

  14. Influence of method of preparation of Pt Ru/C electrocatalysts on the catalytic activity for the ethanol oxidation reaction in acidic medium; Influencia do metodo de preparacao de eletrocatalisadores PtRu/C sobre a atividade catalitica frente a reacao de oxidacao de etanol em meio acido

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Walber dos Santos; Silva, Uriel Lean Valente; Souza, Jose Pio Iudice de, E-mail: jpio@ufpa.br [Universidade Federal do Para, (UFPA), Belem, PA (Brazil). Instituto de Ciencias Exatas e Naturais. Faculdade de Quimica

    2013-09-01

    In this work the influence of variations in the borohydrate reduction method on the properties of Pt Ru/C electrocatalysts was investigated. The electrocatalysts were prepared using 1:1 ; 2:1; 5:1; 50:1 and 250:1 molar ratios of NaBH{sub 4} to metals. The reduction was also performed by dripping or by fast addition of the solution. The results showed that Pt Ru nanoparticles obtained by fast addition had the smallest crystallite sizes. It was also noted that the catalytic activity increased as the borohydrate:metal molar ratio increased. The Pt Ru/C electrocatalysts (50:1) obtained by fast addition presented the best catalytic activity for ethanol electro-oxidation. (author)

  15. Assessment of micro, macro, toxic elements (Cd, Hg, Pb) and fatty acids profile in consumed fish commercially available in Cananeia and Cubatao, Sao Paulo State; Avaliacao de micro e macroelementos, elementos toxicos (Cd, Hg e Pb) e acidos graxos, em peixes disponiveis comercialmente para consumo em Cananeia e Cubatao, Estado de Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Curcho, Michel Rodrigues da Silva Morales

    2009-07-01

    Aside from their nutritional importance, fish are considered one of the most important bio indicators in aquatic systems for the estimation of pollution levels by toxic metals. This is so, since fish can bio accumulate these elements and they occupy different trophic levels and present different sizes and age. The purpose of the present study was to contribute with important data for the knowledge of nutritional and toxic constituents in muscles of the most consumed fish species from two coastal regions, Cananeia and Cubatao. Cananeia fish species analyzed were: Micropogonias furnieri (Corvina), Macrodon ancylodon (Pescada), Centropomus undecimalis (Robalo peba) and Mugil platanus (Tainha). From Cubatao, Micropogonias furnieri (Corvina), Macrodon ancylodon (Pescada), Menticirrhus americanus (Perna de moca), Sardella braziliensis (Sardinha) and Mugil liza (Tainha). For this study, analytical methodologies were developed and validated, regarding precision and accuracy, by means of certified reference materials. Micronutrients (Ca, Fe, K, Na, Se and Zn) and some trace elements (As, Br, Co, Cr, Rb) in fish muscle were determined by means of neutron activation analysis (NAA). Cold Vapor Atomic Absorption Spectrometry (CV AAS) was used for total Hg determination and Electrothermal Atomic Absorption Spectrometry (ET AAS) for Cd and Pb determinations. Proximate composition determinations according to AOAC methodologies and fatty acids profiles by gas chromatography were done in these muscle fish samples. Regarding fatty acids profile from the {omega}-6 family, Tainha species pool presented the highest values (8.9%) and Pescada species pool the lowest ones (4.4%) for Cananeia species. Fatty acids from the {omega}-3 family, Sardinha pool species presented the highest values (31.8%) for all species analyzed. Regarding micronutrients content great concentration variations between individual of the same species and between different species were observed. Discriminate analysis was used for the values for micronutrient content for all fish species analyzed in order to identify samples of similar chemical composition and respective food habits. Concerning populational risk to toxic elements exposure, in this case As and Hg, it was possible to conclude that Corvina and Pescada from Cananeia and Corvina, Sardinha and Tainha from Cubatao presented the highest values for As exceeding the Brazilian legislation limits for this contaminant. For Hg, all the species analyzed did not exceed the Brazilian legislation limits for predatory and non predatory species. Results from this study also suggest that Corvina species can be used as a bioindicator since this species bioaccumulate metals and remains in the estuary until it reaches adulthood. Thus, Corvina can be considered as a good indicator of the conditions of the coastal region where it inhabits. (author)

  16. Evolution evidence of a basic fluid to an acid based in the analysis of hydrothermal alteration of the geothermic field of the Azufres, Michoacan; Evidencias de evolucion de un fluido basico a acido a partir del analisis de la alteracion hidrotermal del campo geotermico de los Azufres, Michoacan

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Partida, Eduardo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2000-07-01

    Hydrothermal alteration at the Los Azufres geothermal field is mostly composed of calc-silicate minerals that define a propylitic alteration zone, which shows progressive dehydration with depth and temperature increase. A generalized zoning of the calc-silicate zone can be observed, with zeolites in the upper part and epidote-clinozoisite at the deepest levels. An argillic alteration zone overlies the calc-silicate zone and is the dominant surface manifestation of the hydrothermal alteration. In some parts, there is a mineral assemblage composed of kaolinite-alunite-native sulfur-quartz (advanced argillic zone) formed by the interaction of vapor and shallow groundwater. The proto-fluid at the Los Azufres geothermal system is related to a neutral sodium chlorine brine, which favors deep propyllitic alteration (productive zone). This zone is characterized by secondary permeability due to fracturing. At depth the geothermal field is dominated by a pressurized liquid, yielding to vapor at more shallow zone. The gradual change from a liquid to a vapor phase occurs through boiling at depths between 1,200 and 1,500 m, and is accompanied by changes in the hydrothermal alteration mineralogy. The type of alteration passes from proylitic to argillic by means of an oxidation-acidification process, which includes the participation of a gas, particularly CO{sub 2}. Considering the physicochemical characteristic of the brine and the evolution of the paragenetic sequence, the Los Azufres geothermal field could de considered a model for hydrothermal behavior at ore deposits which develop by boiling and oxidation of low sulfidation fossil hydrothermal fluids. [Spanish] En el campo geotermico de Los Azufres la zona de alteracion hidrotermal esta formada en su mayor parte por calcosilicatos (que definen una zona paragenetica del tipo propilitico), los cuales muestran una deshidratacion progresiva conforme se va profundizando e incrementandose la temperatura. Se puede generalizar un zoneamiento evolutivo para los calcosilicatos predominando las zeolitas hacia la cima y la epidota-clinozoicita en los niveles mas profundos. Le sobreyace una zona de argilitizacion que domina las manifestaciones hidrotermales superficiales. En algunas zonas, se tiene la asociacion caolinita-alunita-azufre nativo-cuarzo (zona argilica avanzada) formada por la interaccion vapor-acuifero someros. En el sistema geotermico de Los Azufres el protofluido esta ligado a una salmuera clorurado-sodica de caracter neutro que propicia una alteracion hidrotermal propilitica profunda (zona productoras) y se caracteriza por tener una permeabilidad secundaria debido al fracturamiento. A profundiad el yacimiento es a liquido dominante presurizado para evolucionar a vapor en su parte mas somera. El cambio gradual de la fase liquida a vapor se da por ebullicion a profundidades del orden de 1,200 a 1,500 m, y esta acompanado por cambios igualmente presentes en la mineralogia de alteracion hidrotermal. Ella pasa de propilitica a argilica por un proceso de oxidacion-acidificacion, en donde la participacion de gases, principalmente de CO{sub 2}, es importante. De acuerdo a las caracteristicas fisicoquimicas de la salmuera y la evolucion en las fases parageneticas, el yacimiento de Los Azufres pudiera ser un modelo de comportamiento hidrotermal en el deposito de las menas que se dan por ebullicion y oxidacion de los fluidos hidrotermales fosiles de baja sulfidacion.

  17. Determination of uranium and {sup 2}10Po in the river Odiel to assess the radioactive impact of acid mine drainage; Determinacion de uranio y {sup 2}10Po en el rio Odiel para valorar el impacto radiactivo de los drenajes acidos mineros

    Energy Technology Data Exchange (ETDEWEB)

    Manjon, G.; Lehritani, M.; Mantero, J.; Diaz Frances, I.; Garcia-Tenorio, R.

    2013-07-01

    Since 1986 this research group has been monitoring of radioactive environmental impact in the estuary of the river Odiel, generated by the factories of production of phosphoric acid from Huelva, that emitting NORM waste. Once closed factories, is observed a second source of contamination: mining drains. To verify this source have been studied concentration levels of natural radionuclides in the waters and sediments of the river Odiel, in areas that are incorporated drains. (Author)

  18. Effect of addition of lignin in physical-chemical properties of a polyesters based on glycerol, phthalic and adipic acids; Efeito da adicao de lignina nas propriedades fisico-quimicas de poliesteres a base de glicerol e acidos ftalico e adipico

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, D.H.; Viana, A.P.M.; Lima, A.S.C.; Goncalves, A.P.B.; Miranda, C.S.; Jose, N.M., E-mail: dhanseng@yahoo.com.br [Universidade Federal da Bahia (UFBA), alvador, BA (Brazil)

    2014-07-01

    In this paper the study of different addition amounts of lignin in the physicochemical properties of polyesters made from glycerol and different amounts of phthalic and adipic acids have been proposed. The following characterizations were made: XRD, FTIR, TGA, DSC and SEM. The variation in the percentage of adipic and phthalic acids had a direct effect on thermal and morphological properties. The thermal analysis showed that there was miscibility between the polyester and lignin, by means of displacement related to the temperature of thermal degradation events. In FTIR analysis was noted displacements of characteristic bands of hydrogen bonds and specific carbonyl ester groups. These shifts were more pronounced as it has larger amounts of phthalic acid as monomer and larger amounts of lignin in the compositions. (author)

  19. Characterization of ZrP{sub 2}O{sub 7} modified with oxalic acid and thermodynamic analysis associated to the uranyl (Vi) sorption; Caracterizacion de ZrP{sub 2}O{sub 7} modificado con acido oxalico y analisis termodinamico asociado a la sorcion de uranilo (VI)

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.; Ordonez R, E. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Solis C, D. A. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon y Paseo Tollocan, 50120 Toluca, Estado de Mexico (Mexico); Simoni, E.; Drot, R.; Jeanson, A., E-mail: eduardo.ordonez@inin.gob.mx [Universite Paris-Sud, Institut de Physique Nucleaire, Georges Clemenceau No. 15, Orsay (France)

    2013-10-15

    Several physical and chemical tests were carried out to evaluate the influence of the oxalic acid in the uranium (Vi) sorption on the surface of the zirconium diphosphate. The physical analyses consist of atomic force microscopy (AFM) and total organic coal, and the chemists are the calculation of the reaction heat for the hydrate and sorption processes, the reaction speed constant and the sorption yield in the sodium perchlorate systems and of oxalic acid; these tests allow to corroborate that the oxalic acid influences positively in the uranium (Vi) sorption forming a ternary system of ZrP{sub 2}O{sub 7}/(C{sub 2}O{sub 4})/U(Vi), with a single configuration along the ph interval studied. (Author)

  20. Polarographic study of the Cu(II)/Cu(I) system in the presence of 1-ascorbic acid and 0,1 M ClK; Estudio polarografico del sistema Cu(II)/Cu(I) en presencia del acido 1-ascorbico y en ClK 0,1 M

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Lopez, J

    1969-07-01

    While studying the catalytic effect of Cu{sup {down_arrow}}2 ions on the oxidation process of 1-ascorbic acid, it has been observed that, in a 0,1 M solution of K1 at a pH 6 to 7, the above acid gives rise in the presence of Cu{sup {down_arrow}}2 ions to a polarographic wave of half-wave potential of -0,41 V (vs. S.C.E.). (Author) 14 refs.

  1. Chemical recycling of post-consumer PET: structural characterization of terephthalic acid and the effect of Alkaline Hydrolysis at low temperature; Reciclagem quimica do PET pos-consumo: caracterizacao estrutural do acido tereftalico e efeito da hidrolise alcalina em baixa temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Talitha Granja; Almeida, Yeda Medeiros Bastos de; Vinhas, Gloria Maria, E-mail: gmvinhas@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Quimica

    2014-09-15

    Due to the environmental impact caused by PET packaging disposal, this material recycling has been thoroughly discussed and evaluated. In particular, chemical recycling enables achievement of the monomers that are used in PET resin manufacture: ethylene glycol (EG) and terephthalic acid (PTA). Therefore, studies for this process optimization are important from environmental and economic points of view. The present study investigated certain parameters that influence the depolymerization reaction of PET post-consumer via alkaline hydrolysis in order to obtain PTA. Assays were performed at 70 °C by varying the concentration of sodium hydroxide and the reaction time. The best results were obtained at 10.82 mol L{sup -1} NaOH and 9 h reaction time. Consequently, it was possible to prove this process viability, once analyses by infrared and nuclear magnetic resonance confirmed that PTA was obtained in all reactions performed. (author)

  2. Oxidizing gel formulation for nuclear decontamination: rheological and acidic properties of the organic matrix and its ozonolysis; Formulation d'un gel oxydant a matrice organique applicable a la decontamination nucleaire: proprietes rheologiques, acido-basiques et ozonolyse de la matrice

    Energy Technology Data Exchange (ETDEWEB)

    Rouy, E

    2003-10-15

    An acidic and oxidizing gel was formulated with a purely organic matrix, xanthan gum, at low concentrations (1 to 2 wt %). This polymer gel was investigated in various media (aqueous, acidic and ceric) by means of rheology: shear thinning behaviour, thixotropy, yield stress... Evidences of unexpected rheological properties in highly concentrated media show that xanthan is quite convenient for industrial projection of this type of gel on metallic walls in nuclear plants, notwithstanding its time-limited resistance to oxidation (about a few hours). Complexation mechanisms between ceric species and polar sites of the polymer led us to characterise acidic properties of our xanthan sample by potentiometric titration and {sup 1}H NMR techniques. The matrix was finally treated by ozonolysis to suppress organic residues, as required to handle nuclear wastes. In acidic medium, ozonolysis of the gel was achieved successfully while in acidic and ceric medium this process showed limited efficiency, needing further investigation to be clarified. (author)

  3. Determination of glyphosate residuals and of their metabolite Aminomethyl-Phosphonic acid in waters, by means of liquid chromatography of high efficiency with post-column derivation and fluorescence detection; Determinacion de residuos de glifosato y de su metabolito acido aminometilfosfonico en aguas, mediante cromatografia liquida de alta eficiencia con derivacion poscolumna y deteccion por fluorescencia

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Hugo A; Guerrero, Jairo; Castro, Rene

    2002-07-01

    The glyphosate is a no selective herbicide largely used in the world in order to control annual and perennial weeds. Its principal metabolite in soils and waters is the Aminomethyl-Phosphonic Acid (AMPA) formed by micro organism's action. This herbicide is used in Colombia in high doses to illegal crops eradication of coca and Amapola and like natural accelerator in sugar cane, constituting an environmental and social problem for the country, being necessary the evaluation of glyphosate residues in different matrices. This study describes the validation of the analytical methodology for the simultaneous determination of glyphosate and its metabolite AMPA in waters of some Colombian regions. The experimental procedure pointed out two main steps: the first one was a cleaning, extraction and concentration step by solid phase extraction; the second step is the separation, identification and quantification of the compounds by High Performance Liquid Chromatography (HPLC) with post-column derivation and fluorescence detection. The results of the validation show that the methodology is specific, selective, precise and robust with linear calibration curve in the linear range between 10 and 750 {mu}g/L, with limits of detection of 0.8 {mu}g/L and limits of quantification of 2 {mu}g/L for the two analyses. The recoveries are in the order of 73% for glyphosate and 70% for AMPA. More over analysis results are presented for water samples of some country regions where glyphosate is applied in different doses with different purposes, finding residues of the herbicide and its metabolite in concentrations above the allowed values in drinking waters for pesticides of toxicology category IV, like the glyphosate, according with the Colombian legislation.

  4. Synthesis of zeolites coal ash in surfactant modified in application and removal of orange 8 acid solution: study in batch, fixed bed column and evaluation ecotoxicological; Sintese de zeolitas de cinzas de carvao modificada por surfactante e aplicacao na remocao de acido laranja 8 de solucao aquosa: estudo em leito movel, coluna de leito fixo e avaliacao ecotoxicologica

    Energy Technology Data Exchange (ETDEWEB)

    Magdalena, Carina Pitwak

    2015-09-01

    In this study, synthesized zeolitic material from coal ash and modified cationic surfactant was used for removing the acid dye Orange 8 (AL8) by adsorption process using moving bed and fixed-bed column. The raw material and adsorbents were characterized by different techniques, such as X-ray diffraction, X-ray fluorescence spectroscopy, among others. The adsorption of AL8 was performed by moving bed in order to optimize the results when they are launched in a fixed bed. The effects of adsorption on zeolite AL8 were compared: (1) Effect of counterions Br{sup -} and Cl{sup -} surfactant used in the modification of the zeolite; (2) effect of type of coal ash used as raw material in the synthesis of zeolites (fly and bottom). The following adsorbents were used in the study: fly and bottom zeolite modified by surfactant hexadecyltrimethylammonium bromide (ZLMS-Br-Br and ZPMS-Br) and fly zeolite modified by surfactant hexadecyltrimethylammonium chloride (ZLMS-Cl). The pseudo-second-order kinetic described the adsorption of the dye on all adsorbents. The equilibrium time was reached 40, 60 and 120 min for ZLMS-Br, ZLMS-Cl and ZPMS-Br, respectively. The adsorption equilibrium was analyzed by the equations of the models of linear and nonlinear isotherms of Langmuir, Freundlich, Temkin and Dubinin- Radushkevivh (DR) and the criterion of best fit was evaluated using the error functions.The DR model was adjusted better to the experimental data for the system AL8 / ZLMS-Br, the Freundlich model for AL8 / ZLMS-Cl and Langmuir for AL8 / ZPMS. According to the Langmuir maximum adsorption capacity was 4.67, 1.48 and 1.38 mg g{sup -1} for ZLMS-Br, ZLMS-Cl and ZPMS-Br, in order. In studies employing fixed bed columns, the effects of inlet concentration (20- 30 mg L{sup -1}), flow rate (4.0 -5.3 mL min{sup -1}) and the bed height (5, 5 - 6.5 cm) above the breakthrough curves characteristics in the adsorption system were determined. The Adams-Bohart, Thomas, Yoon-Nelson models were applied to experimental data to predict the breakthrough curves and to determine the parameters that characterize the column. The mathematical models of Thomas and Yoon-Nelson adjusted well to the data of breakthrough curves. The highest bed capacity of 5.3 mg g{sup -1} was obtained using 30 mg L{sup -1} inlet Acid Orange 8 concentration, 5.5 cm bed height and 5.3 mL min{sup -1} flow rate. Acute ecotoxicity tests using Daphnia similis microcrustacean with wastewater (AL8) and after treatment with surfactant modified zeolite were carried out with the purpose of evaluating evidence of possible contamination when launched on the receiving water body. The results of this study showed that samples AL8 dye in aqueous solution does not show any toxic effect, and the treated samples showed toxicity with ZLMS-Br. (author)

  5. Comparison of the efficacy of carbamazepine, haloperidol and valproic acid in the treatment of children with Sydenham´s chorea: clinical follow-up of 18 patients Comparación de la eficacia de carbamazepina, haloperidol y acido valproico en el tratamiento de niños con corea de Sydenham: seguimiento clínico de 18 pacientes

    Directory of Open Access Journals (Sweden)

    Joaquín Peña

    2002-06-01

    Full Text Available In order to compare and contrast the efficacy of haloperidol, carbamazepine, and valproic acid in the treatment of Sydenham´s chorea a prospective study including 18 cases of this disorder was undertaken. Age of patients ranged from 7 to 15 years. Ten children were female and 8 were male. All but one had generalized, either symmetric or asymmetric chorea. The patients were divided in three equal groups, and were given a standardized dose of each of the drugs built-up over a week. Following therapy, the six children receiving valproic acid showed remarkable improvement, without side effects. Five patients receiving carbamazepine showed improvement without side effects. Only three of the patients that received haloperidol improved. In the 4 cases that did not show clinical improvement after one week of treatment, therapy with valproic acid led to disappearance of the symptoms in a lapse that ranged from 4 to 7 days. Recurrence related to discontinuation of treatment was observed in two patients. In view of the present results we recommend valproic acid as the first choice drug to treat Sydenham chorea.A fin de comparar y contrastar la eficacia de haloperidol, carbamazepina y ácido valproico en el tratamiento de la corea de Sydenham, se realizó un estudio prospectivo que incluyó 18 casos de esta patología. La edad de los pacientes varió de 7 a 15 años. Diez de los niños eran varones y el resto hembras. A excepción de uno de ellos, todos tenían corea generalizada, simétrica ó asimétrica. Los pacientes fueron divididos en tres grupos iguales, a cada uno de los cuales se le administró una dosis estandarizada de los medicamentos mencionados durante una semana. Luego del tratamiento, los seis pacientes que recibieron ácido valproico mostraron mejoría notable sin efectos colaterales. Cinco de los seis pacientes que recibieron carbamazepina exhibieron mejoría sin efectos colaterales. Solo tres de los pacientes que recibieron haloperidol mejoraron. En los cuatro casos que luego de recibir estas dos últimas drogas sin experimentar mejoría clínica luego de una semana, se instaló terapia con ácido valproico, lo que llevó a desaparición de la sintomatología en un lapso de 4 a 7 días. Se observó recaída relacionada con tratamiento discontinuado en dos de los pacientes. A la vista de nuestros resultados, recomendamos el ácido valproico como droga de primera elección en el tratamiento de la corea de Sydenham.

  6. Study of conformational and acid-base properties of norbadione A and pulvinic derivatives: Consequences on their complexation properties of alkaline and alkaline earth cations; Etude des proprietes conformationnelles et acido-basiques de la norbadione A et de derives pulviniques: consequences sur leurs proprietes complexantes de cations alcalins et alcalino-terreux

    Energy Technology Data Exchange (ETDEWEB)

    Kuad, P

    2006-01-15

    This work deals with the study of norbadione A, a pigment extracted from mushrooms and known to complex cesium cations. The study of the acid-base properties of norbadione A has allowed to determine the relative acidity of the seven protonable functions of the molecule and to reveal a reversible isomerization of the double exocyclic bond of the pulvinic moieties. The observed change of configuration is induced by a hydrogen bond of the H-O-H type and by electrostatic interactions. Moreover, the microscopic protonation mechanism of the norbadione A has been analyzed, considering three different study media where the acid-base properties of the norbadione A are compared. In the presence of 0.15 mol.l{sup -1} of NaCl, it has been observed a remarkable cooperativity in the protonation of the enol groups. At last, the use of different analytical methods (NMR, potentiometry and calorimetry) has allowed to study the complexing properties of the norbadione A towards cesium and other alkaline and rare earth cations. (O.M.)

  7. Evaluation and characterization of ceramic membranes based on Pdms/SiC containing phosphotungstic acid as electrolytes for PEM-FC; Avaliacao e caracterizacao de membranas ceramicas condutoras a base de PDMS/SiC contendo acido fosfotungstico como eletrolito para PEM-FC

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Marcelo de Oliveira; Guimaraes, Danilo Hansen; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais; Barbosa, Diego Augusto Batista; Paschoal, Carlos William de Araujo [Universidade Federal do Maranhao (DF/UFMA), Sao Luis, MA (Brazil). Dept. de Fisica; Almeida, Rafael Mendonca; Tanaka, Auro Atsushi [Universidade Federal do Maranhao (DQ/UFMA), Sao Luis, MA (Brazil). Dept. de Quimica

    2009-07-01

    This work presents the development of membranes with potential use in Proton Exchange Fuel Cells (PEM-FC), consisting of hybrid materials based on poly(dimethylsiloxane), crosslinked with tetraethyl orthosilicate (TEOS), and reinforced with silicon carbide and phosphotungstic acid. The membrane series PDMS/TEOS/SiC/PWA were prepared by the reaction of PDMS and TEOS, 70/30% proportions in mass, catalyzed by dibutyltin dilaurate. SiC was incorporated in a 25% proportion, and PWA in varied proportions (5, 10, 15 and 20%), by weight. The membranes were characterized by Thermo-Gravimetric Analysis (TGA), X-ray Diffraction, Scanning Electron Microscopy and impedance spectroscopy. SiC and PWA addition to the membrane increased both structure organization and material crystallinity. The insertion of PWA provided an increase in the conductivity. However, maximum conductivity was obtained with concentration levels above 10%. The insertion of SiC associated with the PWA did not influence the conductivity for concentrations between 10 and 20%. (author)

  8. Determination of the longitudinal relaxation time (T{sub 1}) of the carbon for the caura-16-E N-19-oic acid; Determinacao do tempo de relaxacao longitudinal (T{sub 1}) do carbono para derivados do acido-caura-16-en-19-oico

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, J A; Rodrigues, A S [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica

    1992-12-31

    In this work, we analyse, through the {sup 13} C longitudinal relaxation time (T{sub 1}), the solute-solute and solute-solvent interactions in some molecules of the c aura-16-en-19-oic acid such as: c aura-16-en-19-oic acid (I), c aura-15-acetoxy-16-en-19-oic acid (II), methyl esther of the c aura-16-en-19-oic acid (III) and c aura-16-en-19-ol (IV) 5 refs., 1 fig., 1 tab.

  9. LACTIC ACID BACTERIA WITH ANTIMICROBIAL ACTIVITY AGAINST PATHOGENIC AGENT CAUSING OF BOVINE MASTITIS BACTERIAS ACIDO LACTICAS CON ACTIVIDAD ANTIMICROBIANA CONTRA PATÓGENOS CAUSANTES DE MASTITIS BOVINA OUT BACTÉRIAS LÁTICAS COM ATIVIDADE ANTIMICROBIANA CONTRA OUT PATÓGENOS DA MASTITE BOVINA

    OpenAIRE

    LILIANA SERNA C; LEIDY JOHANA VALENCIA H; RÓMULO CAMPOS G

    2011-01-01

    The use of antibiotics to treat bovine mastitis, produces antibiotic residues in milk and decreased quality of dairy products. Lactic acid bacteria have been proposed as an alternative to avoid the use of antibiotics. This paper reports the antimicrobial activity against pathogens responsible of bovine mastitis, of 4 lactic acid strains isolated from cattle in a state of acidosis ruminal. It also evaluated the specific growth rate (m) and antimicrobial activity of one of the strains, using tw...

  10. Determination of the extractive capacity of para-tert butyl calix[8]arene octa-phosphinoylated towards uranyl ions from an aqueous-acidic-salty medium; Determinacion de la capacidad extractiva del p-ter-butilocalix[8]areno octa-fosfinoilado hacia iones uranilo de un medio acuo-acido salino

    Energy Technology Data Exchange (ETDEWEB)

    Serrano V, E. C.

    2011-07-01

    The extraction properties of octa-phosphinoylated para-tert butyl calix[8]arene (prepared in the laboratory) in chloroform towards uranyl ions from an aqueous-acidic-salty medium (HNO{sub 3}-3.5 NaNO{sub 3}) containing uranyl nitrate salt, was investigated. Two spectroscopic techniques UV/Vis and Luminescence were used for this study. The latter permitted analyze the fluorescence from the uranyl ions influenced by the surrounding medium. Both permitted to learn about the power of this calixarene as extractant towards the mentioned ions. Its extraction ability or capability using this calixarene at 5.91 x 10{sup -4} M towards the uranyl ions was 400% as determined by UV/Vis while fluorescence revealed 100% of uranyl ion extraction. A closed analysis of the results obtained by using these techniques revealed that the stoichiometry of the main extracted species was 1calixarene:2 uranyl ions. The loading capacity of the calixarene ligand towards the uranyl ions was also investigated using both techniques. UV/Vis resulted to be inadequate for quantifying exactly the loading capacity of the calixarene whereas luminescence was excellent indeed, using a 5.91 x 10{sup -4} M calixarene concentration, its loading capacity was 0.157 M of free uranyl ions from 0.161 M of uranyl ions present in the aqueous-acidic-salty medium. The extracts from the ability and capacity studies were concentrated to dryness, purified and the dried extracts were analyzed by infrared and neutron activation analysis. By these techniques it was demonstrated that during the extraction of the uranyl ions by the calixarene ligand they form thermodynamically and kinetically stable complexes, since in the solid state, the 1:2, calixarene; uranyl ions stoichiometry was kept with the minimum formula: (UO{sub 2}){sub 2}B{sub 8}bL{sup 8}(NO{sub 3}){sub 4}(H{sub 2}O){sub 4}CHCl{sub 3}(CH{sub 3}OH){sub 3} the methanol molecules come from its purification. It is proposed that B{sub 8}bL{sup 8} calixarene in chloroform medium is a good extractant for the treatment of nuclear wastes or radioactive wastes containing uranium in a rich aqueous-acidic-salty medium. (Author)

  11. Synthesis of aluminum oxide by the polymer precursor method (Pechini) in 4: 1 ratio of citric acid: metal cation: calcination temperature effect; Sintese do oxido de aluminio pelo metodo dos precursores polimericos (Pechini) na relacao 4:1 de acido citrico: cation metalico: efeito da temperatura de calcinacao

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.C.; Lira, H.L.; Ribeiro, P.C.; Freitas, N.L., E-mail: mirelecsilva@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais

    2014-07-01

    The technology field is nanopowders prominent in science since these materials fall in various sectors regarding their applications. This work aims at the synthesis of aluminum oxide by polymeric precursors in 4:1 ratio of citric acid:metal cation and evaluate the influence of calcination temperature on their structural and morphological characteristics. The samples after reaction were characterized by XRD and thermal analysis. After calcination 500-1200°C the samples were characterized by XRD, SEM and particle size distribution. The results showed that the variation of the calcination temperature is sufficient to achieve a same material with different structural and morphological characteristics. The most stable phase aluminum oxide arose only after calcination at 1100°C, below 900°C, the amorphous material appeared. As regards the morphology, the change was not as significant as compared to the structure. (author)

  12. Study of the influence of the citric and oxalic acid in the uranyl sorption in ZrP{sub 2}O{sub 7} for their use in contention barriers; Estudio de la influencia del acido citrico y oxalico en la sorcion de uranilo en ZrP{sub 2}O{sub 7}, para su uso en barreras de contencion

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N.

    2009-07-01

    Countries which produce electricity by nuclear means, such as Mexico, need to develop a technology for that at long term safe containment of nuclear waste that are produced in nuclear power plants, for now, the arrangement of these is made by international companies, as which is extremely expensive. The most accepted proposal for the containment of radioactive waste is the Deep Geological Repository (DGR), which consists of a number of natural barriers and of engineering barriers. Currently, barriers to engineering and materials that the make up are still under study, because must meet a series of structural criteria and chemical such as high insolubility, thermal and chemical stability with ionizing radiation. The surface must have adsorbed features of ions and organic compounds dissolved in infiltration water that could penetrate for a crack in the DGR. This study focuses, as first stage, is the uranyl sorption on zirconium diphosphate in various conditions of time, concentration and ph, then evaluates the influence of citric acid and oxalic acid on the sorption of uranyl on ZrP{sub 2}O{sub 7}, in order to model the behaviour of alpha emitters that are dissolved by percolating water laden with salts and organic matter, that infiltrates might during catastrophic events in the DGR. It was confirmed the purity of the zirconium diphosphate because it was synthesized from sea sand with the physicochemical characterization and superficial. The proposed methodology included elemental analysis by neutron activation and X-ray emission induced by charged particles, functional group analysis with infrared spectroscopy, morphology with scanning electron microscopy, crystallinity with transmission electron microscopy and X-ray diffraction. For properties surface was determined, the specific area using Bet multipoint technique, acidity constants in the FITEQL 4.0 program, the hydration time was obtained from literature, the point of zero charge was identified with a mass titration and zeta potential, the density of surface sites was determined with acid-base titrations. We evaluated the adsorption of uranyl and adsorption of uranyl complex / organic acid (citric and oxalic) in ZrP{sub 2}O{sub 7} with chemical kinetics using batch technique under different conditions. Quantification and speciation of uranyl, was made by the luminescence technique in their modalities of fluorescence and phosphorescence. It was confirmed that modifying the surface of ZrP{sub 2}O{sub 7} with oxalic acid and citric, different species that were generated on the surface of this, compared with the hydration of sodium perchlorate. (Author)

  13. Characterization and corrosion behavior of phytic acid coatings, obtained by chemical conversion on magnesium substrates in physiological solution; Caracterizacion y comportamiento frente a la corrosion de recubrimientos de acido fitico, obtenidos por conversion quimica, sobre substratos de magnesio en solucion fisiologica

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Alvarado, L. A.; Lomeli, M. A.; Hernandez, L. S.; Miranda, J. M.; Narvaez, L.; Diaz, I.; Garcia-Alonso, M. C.; Escudero, M. L.

    2014-10-01

    In order to improve the corrosion resistance of biodegradable magnesium and AZ31 magnesium alloy implants, a phytic acid coating has been applied on both substrates and their protective effect against corrosion has been assessed. The morphology and the chemical nature of the conversion coating were analyzed by SEM/EDX, XRD and FTIR. The spectra showed that the conversion coating was amorphous, and it was composed of Mg, O, and P on magnesium surface, along with Al, Zn and C on AZ31 alloy. The main coating components were chelate compounds formed by phytic acid and metallic ions. The corrosion resistance of bare and coated samples was evaluated by potentiodynamic polarization technique in Hank's solution at 37 degree centigrade. The results indicate that phytic acid conversion coatings provided a very effective protection to the magnesium substrates studied. (Author)

  14. Preparation of manganese salts of carboxylic acids labelled with ''54Mn and comparison with ''54 MnCl{sub 2} in liquid scintillation counting; Preparacion de sales manganosas de acidos alifaticos monocarboxilicos marcados con ''54 MnCl{sub 2} en medidas por centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Barquero, L.; Arcos Merino, J. M. los; Grau Malonda, A.

    1992-07-01

    Procedures for liquid scintillation sample preparation of manganese dimethylbutirate, decanoate and palmitate, labelled with 54 Mn are described. their quenching effect, spectral evolution and counting stability along several weeks are analysed in liquid scintillation measurements with Toluene. HISafe II. PCS, instagel. Dioxane-naphtalene and Toluene-alcohol. For comparison, Inorganic 54 MnCl-2 samples are also studied, resulting in acceptable counting stability but showing greater quenching and signs of little spectral degradation against the organic samples. (Author)

  15. Determinacion de la configuracion E-Z de los acidos Fumarico y Maleico. Un experimento orientado a incentivar el desarrollo de la investigacion cientifica en alumnos de Pregrado Determination of the E-Z fumaric and maleic acids configuration. An experiment designed to develop scientific research abilities in undergraduates students

    Directory of Open Access Journals (Sweden)

    Carlos Bustos

    2000-08-01

    Full Text Available In this work we intend to eliminate the idea that laboratory exercises seem like cookbooks. That is, exercises shall be presented as a problematic situation. Based on observation and experimentation, the students should determine the E-Z configuration of maleic and fumaric acids. The basis of this laboratory exercise is the acid-catalyzed isomerization of maleic acid to fumaric acid. Students are given the starting material, reagents and the experimental procedure. They are told that the starting material is a dicarboxylic acid containing a C=C double bond of formula C4H4O4. Students determine melting points, solubilities, acidity and chromatographic patterns for both the starting material and the product, so that a configuration of each acid can be proposed. This type of experiment yields excellent results, because the students are left to deduce that maleic acid is less stable than fumaric acid. Additionally, they conclude that maleic acid is the "Z" isomer and fumaric acid is the "E" isomer. Finally, this laboratory exercise allows the students to develop simultaneously their critical-thinking skills with the respective laboratory techniques and not to see chemistry as recipes to be followed.

  16. Sterilization by Gamma-Radiation of the Sodium Salt of p-Amino-Salicylic Acid; Sterilisation par irradiation gamma du sel sodique de l' acide p-amino salicylique; Sterilizatsiya gamma-oblucheniem natrievoj soli paraaminosalitsilovoj kisloty; Esterilizacion porirradiacion gamma dela sal sodica del acido p-aminosalicilico

    Energy Technology Data Exchange (ETDEWEB)

    Bellion, B.; Denti, E.; Massagli, A. [Sorin, Centro Ricerche Nucleari, Saluggia (Italy)

    1963-11-15

    Sodium p-amino-salicylate cannot be sterilized thermally. During manufacture or packing for medical purposes it must therefore be handled under sterilized conditions, with all the difficulties which this involves. The paper quotes experimental data to show that, using gamma irradiation, the product may be sterilized without damage and without the formation of substances harmful from the medical standpoint. (author) [French] Le p-amino salicylate de sodium ne peut Etre sterilise par la chaleur. Pour l'emploi de ce produit comme medicament on est donc oblige de l e manipuler tant pour la fabrication que pour l'emballage, dans des locaux steriles, avec toutes les difficultes qui s'ensuivent. Dans ce travail, les auteurs ont pu demontrer experimentalement la possibilite de steriliser le produit par irradiation gamma, sans endommager le produit et sans formation de substances nocives pour l'emploi medical. (author) [Spanish] El pamino salicilato de sodio no puede esterilizarse por vfa termica y, por lo tanto, para emplearlo como medicamento es preciso prepararlo y empaquetarlo en locales esterilizados, con las dificultades consiguientes; Los autores han demostrado experimentalmente que es posible esterilizar este compuesto por exposicion a los rayos gamma, sin alterarlo y sin que se formen substancias nocivas desde el punto de vista medico. (author) [Russian] Natrievaya sol' paraaminosalitsilovoj kisloty ne mozhet byt' sterilizovana pri pomoshchi nagreva, i dlya togo, chtoby ispol'zovat' ehtot produkt v kachestve medikamenta, nuzhno obrabatyvat' ego kak v protsesse proizvodstva, tak i pri upakovke v steril'nykh pomeshcheniyakh so vsemi vytekayushchimi otsyuda trudnostyami. V dannoj rabote avtory smogli ehksperimental'nym putem dokazat' vozmozhnost' sterilizatsii ehtogo produkta gamma-oblucheniem bez ushcherba dlya ehtogo produkta i bez obrazovaniya vrednykh veshchestv, chto pozvolyaet ego v meditsine. (author)

  17. Radiomimeticity of the system H{sub 2}O{sub 2}/Fe(II) on nucleic acid components. Kinetics study; Radiomimeticidad del sistema H{sub 2}O{sub 2}/Fe(II) sobre components de Acidos Nucleicos. Estudio Cinetico

    Energy Technology Data Exchange (ETDEWEB)

    Cirauqui, R; Mingot, F; Davila, C A

    1974-07-01

    The kinetic study of the action of a redox system on DNA monomers allowed us to make criticisms on radiomimetic character of this system. Assuming that in both cases, gamma radiolysis of aerated aqueous solutions and action of H{sub 2}O{sub 2} / Fe(II) system in the same conditions, the reactive species is the OH radical, we propose the kinetic expressions that are confirmed by our experimental results. Some of the accepted G-values are corrected in view of our results. Al so these results put in evidence mechanisms of molecular repair after radical attack. (Author) 79 refs.

  18. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement; Selamento de fossulas e fissura de segundo molar deciduo inferior com laser de Nd: YAG, acido fosforico e cimento de ionomero de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Maria Aparecida

    2003-07-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 {mu}m diameter; fluency of 99,52 J/ cm{sup 2}, assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  19. Synthesis of polyaniline catalysed by Cu(I), Ni(II) and Fe(II) supported on the polyethylene-i-acrylic acid copolymer; Sintesis de polianilina catalizada por Cu(I), Ni(II) y Fe(II), soportados en el copolimero polietileno-i-acido acrilico

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, L.; Urena, F.; Lopez, R. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    In this study the active sites of acrylic acid (AA) were grafted in low density polyethylene (PEBD) using gamma radiation. Subsequently, the graft copolymer PEBD-i-AA was coordinated with different metals such as copper, nickel and iron. The organometallic copolymers so formed were used as catalysts in the aniline polymerization reaction. Finally, it was realized the characterization of the obtained products, determining their thermal properties, copolymer graft percentage, quantification of the metal contained in the complex as well as polymerization and electric conductivity percentages of the poly aniline film. (Author)

  20. Oxidizing gel formulation for nuclear decontamination: rheological and acidic properties of the organic matrix and its ozonolysis; Formulation d'un gel oxydant a matrice organique applicable a la decontamination nucleaire: proprietes rheologiques, acido-basiques et ozonolyse de la matrice

    Energy Technology Data Exchange (ETDEWEB)

    Rouy, E

    2003-10-15

    An acidic and oxidizing gel was formulated with a purely organic matrix, xanthan gum, at low concentrations (1 to 2 wt %). This polymer gel was investigated in various media (aqueous, acidic and ceric) by means of rheology: shear thinning behaviour, thixotropy, yield stress... Evidences of unexpected rheological properties in highly concentrated media show that xanthan is quite convenient for industrial projection of this type of gel on metallic walls in nuclear plants, notwithstanding its time-limited resistance to oxidation (about a few hours). Complexation mechanisms between ceric species and polar sites of the polymer led us to characterise acidic properties of our xanthan sample by potentiometric titration and {sup 1}H NMR techniques. The matrix was finally treated by ozonolysis to suppress organic residues, as required to handle nuclear wastes. In acidic medium, ozonolysis of the gel was achieved successfully while in acidic and ceric medium this process showed limited efficiency, needing further investigation to be clarified. (author)

  1. Use of probabilistic safety analysis for design of emergency mitigation systems in hydrogen producer plant with sulfur-iodine technology, Section II: sulfuric acid decomposition; Uso de analisis probabilistico de seguridad para el diseno de sistemas de mitigacion de emergencia en planta productora de hidrogeno con tecnologia azufre-iodo, Seccion II: descomposicion de acido sulfurico

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza A, A.; Nelson E, P. F.; Francois L, J. L. [Facultad de Ingenieria, Departamento de Sistemas Energeticos, UNAM, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico)], e-mail: iqalexmdz@yahoo.com.mx

    2009-10-15

    Over the last decades, the need to reduce emissions of greenhouse gases has prompted the development of technologies for the production of clean fuels through the use of primary energy resources of zero emissions, as the heat of nuclear reactors of high temperature. Within these technologies, one of the most promising is the hydrogen production by sulfur-iodine cycle coupled to a high temperature reactor initially proposed by General Atomics. By their nature and because it will be large-scale plants, the development of these technologies from its present phase to its procurement and construction, will have to incorporate emergency mitigation systems in all its parts and interconnections to prevent undesired events that could put threaten the plant integrity and the nearby area. For the particular case of sulfur-iodine thermochemical cycle, most analysis have focused on hydrogen explosions and failures in the primary cooling systems. While these events are the most catastrophic, is that there are also many other events that even taking less direct consequences, could jeopardize the plant operation, the people safety of nearby communities and carry the same economic consequences. In this study we analyzed one of these events, which is the formation of a toxic cloud prompted by uncontrolled leakage of concentrated sulfuric acid in the second section of sulfur-iodine process of General Atomics. In this section, the sulfuric acid concentration is near to 90% in conditions of high temperature and positive pressure. Under these conditions the sulfuric acid and sulfur oxides from the reactor will form a toxic cloud that the have contact with the plant personnel could cause fatalities, or to reach a town would cause suffocation, respiratory problems and eye irritation. The methodology used for this study is the supported design in probabilistic safety analysis. Mitigation systems were postulated based on the isolation of a possible leak, the neutralization of a pond of sulfuric acid and finally washing the same; later some scenarios and modifications were analyzed to determine their impact on the likelihood of failure system and provide feedback design with the information produced in the probabilistic safety analysis. (Author)

  2. Influence of the acid and basic properties of rhenium oxide supported on alumina catalyst on the catalytic performance in olefin metathesis; Influence des proprietes acido-basiques de l`oxyde de rhenium supporte sur les performances catalytiques en metathese des olefines

    Energy Technology Data Exchange (ETDEWEB)

    Nahama, F.

    1996-11-30

    The aim of this work is to study the influence of the acid-basic properties of rhenium oxide supported on alumina catalyst on the catalytic performance in olefin metathesis. The literature data indicate that the environment of the active site does possess acid properties. However, the nature of the acid sites is still matter of debate. Concerning the Re O{sub x} - Al{sub 2}O{sub 3} interactions, we have shown that perrhenate ions are electrostatically absorbed on alumina. The uptake of rhenium is favoured at acidic pH (below 4), and the absorbed rhenium is in equilibrium with rhenium in solution. The results of rhenium extraction by water strongly suggest that the surface compounds of the calcined Re{sub 2}O{sub 7}/Al{sub 2}O{sub 3} materials is aluminium perrhenate. Characterization of surface acidity of the catalyst by infrared spectroscopy reveals that the initiation of the metathesis reaction is governed essentially by Lewis acidity. This strongly supports the role of Lewis acidity, which is exalted by the increase of the rhenium content and the calcination temperature. Finally, we point out by ammonia adsorption-thermodesorption a band at 1320 cm{sup -1} characteristic of the Lewis acidity of aluminium perrhenate. This result is a second indication of the presence of aluminium perrhenate on the Re{sub 2}O{sub 7}/Al{sub 2}O{sub 3} catalyst surface. (author)

  3. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement; Selamento de fossulas e fissura de segundo molar deciduo inferior com laser de Nd: YAG, acido fosforico e cimento de ionomero de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Maria Aparecida

    2003-07-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 {mu}m diameter; fluency of 99,52 J/ cm{sup 2}, assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  4. Evaluation of mitomycin-C effect on biodistribution of {sup 99m}Tc-dimercaptosuccinic acid in BALB/C mice; Avaliacao do efeito da mitomicina-c na biodistribuicao do radiofarmaco acido dimercaptosuccinico marcado com tecnecio-99m em camundongos BALB/C

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Maria Luisa; Britto, Deise Mara de M.; Freitas, Rosimeire de S.; Bernardo-Filho, Mario [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil). Centro de Pesquisa Basica; Braga, Ana Cristina de S.; Bezerra, Roberto Jose A.C. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes. Dept. de Biofisica e Biometria

    1999-11-01

    The many desirable characteristics of technetium-99m have stimulated the development of labeling techniques for different molecular and cellular structures. It is accepted that a variety of factors such the drug chemotherapy can alter the biodistribution of radiopharmaceuticals. The unknowledge of these factor may result in an unexpected behavior of the radiopharmaceuticals. Since patients on chemotherapeutic treatment can be submitted to a nuclear medicine procedure, we have studied in mice, the effect of mitomycin-C on the {sup 99m} Tc-DMSA used for kidney scintigraphy. Mitomycin-C is an antineoplastic agent obtained from Streptomyces caesptosus. The metabolism of this drug produces different toxic and inactive metabolites. Mitomycin-C 0.15 mg was administered in Balb/c female with an interval of 72 hours. After one hour of the last dose, 0.3 ml of 9{sup 9m}c-DMSA (7.4 MBq) were injected and after 0.5 h the animals were sacrificed. The organs were isolated and counted in a well counter. The percentage of radioactivity (%ATI) were calculated and statistical analysis were performed (Wilcoxon Test). The results have shown that the %ATI: has increased in stomach and uterus, has decreased in kidney and ovary; has not altered in pancreas, spleen, lung, heart, liver, thymus, thyroid, bone and brain. The increase of % ATI could be justified by the metabolic process or the therapeutical effect of mitomycin-C. As an effect of this drug is observed in the uptake of the {sup 99m} Tc-DMSA by the kidney, probably an alteration in the kidney scintigraphy is expected. However, the increase of %ATI of this radiopharmaceutical in other organs by the mitomycin-C could be evaluated carefully. (author) 12 ref., 2 tabs.

  5. Utility of the dimercapto succinic acid pentavalent ({sup 99m} Tc- DMSA V) in the diagnostic of secondary bone leisure at metastasis of diverse primary tumours. Preliminary study; Utilidad del acido dimercapto succinico pentavalente ({sup 99m} Tc-DMSA V) en el diagnostico de lesiones oseas secundarias a metastasis de diversos tumores primarios. Estudio preliminar

    Energy Technology Data Exchange (ETDEWEB)

    Ortega L, N [Hospital de Especialidades ' Dr. Antonio Fraga Mouret' Centro Medico Nacional ' La Raza' , IMSS Mexico D.F. (Mexico); Pichardo R, P A [Medico Nuclear adscrito al servicio de Medicina Nuclear del Hospital de Oncologia, Centro Medico Nacional Siglo XXI, IMSS, Mexico D.F. (Mexico); Marquez H, A [Departamento de Medicina Nuclear, IMSS, Mexico D.F. (Mexico)

    2005-07-01

    The more used method in the diagnosis of secondary bone lesions to become cancerous it is by means of having derived of phosphates like it is the {sup 99m}Tc- MDP. The reason of acquiring searching with the radiopharmaceutical {sup 99m}Tc- DMSA V is with the purpose to find other bone lesions that are not visualized with the gammagraphy with diphosphonate and therefore to increase the specificity of the study. (Author)

  6. EFECTO NEFROPROTECTOR DEL ÁCIDO ASCÓRBICO EN UN MODELO DE DAÑO RENAL INDUCIDO POR GENTAMICINA EN CONEJOS

    Directory of Open Access Journals (Sweden)

    Javier Antonio Padilla Funes

    2013-08-01

    Full Text Available Objetivo. Uno de los efectos secundarios mas notables de la Gentamicina es su nefrotoxicidad. En este estudio se propone el posible efecto nefroprotector del acido ascorbico como barredor de radicales libres de oxigeno. Metodología. Se ejecuto un estudio experimental en 24 conejos machos, raza Nueva Zelanda, cuyo peso fue de 1,5 +/- 0,5 Kg. Los sujetos experimentales fueron distribuidos en tres grupos. El grupo Control se manejo con Gentamicina a dosis de 80 mg/Kg/dia por via IM. El grupo Acido Ascorbico se trato a dosis de 200 mg/kg/dia via IP y Gentamicina 80mg/Kg/dia IM. El grupo Sham se manejo con SSN 0,9% por via IP e IM, durante cinco dias consecutivos, para cada grupo. Se determinaron los siguientes parametros: creatinina serica, N-Acetil s-D glucosaminidasa urinaria (NAG-U, diuresis e histopatologia de las muestras renales. Resultados. La creatinina serica fue significativamente mayor para el grupo Control respecto al grupo Acido Ascorbico (p<0,05. Respecto a la diuresis, se observo una tendencia a la poliuria en el grupo Control. En cuanto a NAG-U, se observo inhibicion completa de la actividad enzimatica en el grupo Acido Ascorbico. El analisis histopatologico demuestra hallazgos de necrosis tubular aguda en el 100% del grupo control, mientras que en el grupo Acido Ascorbico se obtuvo en un 50% de los sujetos unicamente detritos intraluminales. Conclusiones. La administracion concomitante de Acido Ascorbico con Gentamicina, disminuye significativamente el dano tubular renal, evidenciado en los valores de creatinina serica, NAG, diuresis e histopatologia renal.

  7. Identificación de defensas inducibles a áfidos en cebadas pre-comerciales

    OpenAIRE

    Caridad, Alejandro; Saldúa, Vilma Luciana; Castro, Ana María

    2018-01-01

    Las plantas tienen la capacidad de adaptarse a situaciones de estrés mediante la expresión de genes implicados en mecanismos de defensa, que pueden ser constitutivos o inducibles, dependiendo si se expresan permanentemente o no. Detrás de la regulación de estos mecanismos se encuentran las hormonas, moléculas señalizadoras que comunican los distintos tejidos de la planta entre sí. Ante el ataque de insectos, el Acido Jasmónico (AJ) y el Acido Salicílico (AS) juegan un papel preponderante en l...

  8. POLYETHYLENEIMINE (PEI ON SILICA AS CATALYST IN KNOEVENAGEL AND MICHAEL REACTIONS

    Directory of Open Access Journals (Sweden)

    FATIHA ZAOUI

    2017-03-01

    Full Text Available After the synthesis of polyethylenimine supported on silica, it has been used as a new and efficient catalyst in Knoevenagel and Michael condensations. The presence of the polyethylenimine in the catalytic system together with silica displays an acido-basic character allows a better catalytic activity in the condensations. Carried out under microwave irradiation, without organic solvent and during short time, the syntheses are respectful towards green chemistry. The solid catalyst can be easily reused. This catalyst has the acido-basic character at the same time.

  9. A method for the determination of ascorbic acid using the iron(II)-pyridine-dimethylglyoxime complex

    Energy Technology Data Exchange (ETDEWEB)

    Arya, S. P.; Mahajan, M. [Haryana, Kurukshetra Univ. (India). Dept. of Chemistry

    1998-05-01

    A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 {mu}g ml{sup -1}. Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C. [Italiano] Si propone un rapido e semplice metodo spettrofotometrico per la determinazione dell`acido ascorbico. L`acido ascorbico riduce il ferro(III) a ferro(II) che forma con la dimetilgliossima, in presenza di piridina, un complesso colorato in rosso. L`assorbanza della soluzione risultante e` misurata a 514 nm e si ottiene una relazione lineare tra assorbanza e concentrazione dell`acido ascorbico fino a 14 {mu}g ml{sup -1}. Si sono condotti studi sugli interferenti usualmente associati all`acido ascorbico ed e` stata valutata l`applicabilita` del metodo all`analisi di preparati farmaceutici di vitamina C.

  10. A randomised controlled trial comparing the effect of adjuvant ...

    African Journals Online (AJOL)

    Results: The duration of effective analgesia was longer in the midazolam group ... There was no significant difference (P 0.4047). ... events, peripheral vasoconstriction, and metabolic acido- .... determined and recorded every hour. ..... scriptions of chronic pain syndromes and definitions of ... Long-term intrathecal adminis-.

  11. Inhibition of fructan-fermenting equine fecal bacteria and Streptococcus bovis by hops (Humulus lupulus L.) ß-acid

    Science.gov (United States)

    Aims: The goals were to determine if the '-acid from hops (Humulus lupulus L.) could be used to control fructan fermentation by equine hindgut microorganisms, and to verify the antimicrobial mode of action on the Streptococcus bovis, which has been implicated in fructan fermentation, hindgut acidos...

  12. 1131-IJBCS-Article-Kouame Guy M Bouafou

    African Journals Online (AJOL)

    DR GATSING

    nutriments sur la base de 4 kcal pour 1 g de protéine, 4 kcal pour 1 g de glucide et 9 kcal pour 1 g de lipide. ... rénal. (Balasubramaiam, 2003). Le rapport normal Ca/P plasmatique est l'indice d'un .... Acido-basiques et Hydroélectrolytiques,.

  13. Kinetics of oxidation of acidic amino acids by sodium N

    Indian Academy of Sciences (India)

    Asp)) by sodium N-bromobenzenesulphonamide (bromamine-B or BAB) has been carried out in aqueous HClO4 medium at 30°C. The rate shows firstorder dependence each on [BAB]o and [amino acid]o and inverse first-order on [H+]. At [H+] > ...

  14. Catalytic mechanism of the dehydrogenation of ethylbenzene over Fe–Co/Mg(Al)O derived from hydrotalcites

    KAUST Repository

    Tope, Balkrishna B.; Balasamy, Rabindran J.; Khurshid, Alam; Atanda, Luqman A.; Yahiro, Hidenori; Shishido, Tetsuya; Takehira, Katsuomi; Al-Khattaf, Sulaiman S.

    2011-01-01

    -H+ abstraction from ethyl group on Mg2+-O2- basic sites, followed by C-O-Mg bond formation. The α-H+ abstraction by O2-(-Mg 2+) was likely followed by β-H abstraction, leading to the formations of styrene and H2. Such catalytic mechanism by the Fe 3+ acid-O2-(-Mg

  15. Performance assessment of the catalyst ZnAl{sub 2}O{sub 4} and Cu/ZnAl{sub 2}O{sub 4} esterification reaction fatty acid in biodiesel; Avaliacao do desempenho do catalisador ZnAl{sub 2}O{sub 4} e Cu/ZnAl{sub 2}O{sub 4} na reacao de estereficacao de acidos graxos em biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Feitosa, A.C.; Dantas, J.; Costa, A.C.M.F., E-mail: alexcaval2@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Barbosa, D.C.; Meneghetti, S.M.P. [Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil). Dept. de Quimica

    2012-07-01

    This study aims to evaluate the performance of the Cu/ZnAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} methyl esterification of fatty acids of soybean oil into biodiesel. The ZnAl{sub 2}O{sub 4} was synthesized by combustion reaction and then the sample was wet impregnated with a copper source. The samples were characterized by XRD, SEM, textural analysis and catalytic tests bench. The characterization results showed that the samples showed characteristic diffraction peaks spinel, with the characteristic of mesoporous material (10-250 Å), particles in the form of blocks and slabs of hard point. The results showed that the conversion impregnation of copper has increased by 17% conversion to biodiesel. (author)

  16. In vitro activity of 2-pyridinecarboxylic acid against trypanosomes of the subgenus Schizotrypanum isolated from the bat Phyllostomus hastatus = Atividade in vitro do ácido 2-piridinocarboxílico em tripanossoma do subgênero Schizotrypanum isolado do morcego Phyllostomus hastatus

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Ceridóreo Corrêa

    2011-09-01

    Full Text Available The effect of 2-pyridinecarboxylic acid (picolinic acid on trypanosomes of the subgenus Schizotrypanum isolated from the bat Phyllostomus hastatus was determined in this study. Picolinic acid, at 50 ƒÊg mL-1, inhibited epimastigote growth by 99% after 12 days incubation. In addition, trypomastigote motility decreased by 50% after 6h and completely after 24h in the presence of 50 ƒÊg mL-1 picolinic acid. The 50% cytotoxic concentration on HEp-2 cell line was275 ƒÊg mL-1 after 4 days incubation. Altogether, these results indicate higher toxicity against trypanosomes. The inhibitory effect of picolinic acid on epimastigote growth can be partially reversed by nicotinic acid and L-tryptophan, suggesting a competitive inhibition. Furthermore, two anti-Trypanosoma (Schizotrypanum cruzi drugs were also evaluated with regard to bat trypanosome growth. Benznidazole, at 50 ƒÊg mL-1, inhibited epimastigote growth by 90% after 12 days incubation. Nifurtimox, at the same concentration, caused 96% growth inhibition after four days incubation. Corroborating a previous study, bat trypanosomes are a good model for screening new trypanocidal compounds. Moreover, they can be used to study many biological processes common to human pathogenic trypanosomatids.O efeito do acido 2- piridinocarboxilico (acido picolinico sobre um tripanossoma do subgenero Schizotrypanum isolado do morcego Phyllostomus hastatus foi determinado neste estudo. O acido picolinico, na concentracao de 50 ƒÊg mL-1, inibiu 99% do crescimento de epimastigotas apos 12 dias de incubacao. Alem disso, houve um decrescimo de 50 e 100% na mobilidade dos tripomastigotas apos 6 e 24h, respectivamente, em presenca de acido picolinico na concentracao de 50 ƒÊg mL-1. A concentracao citotoxica 50% para celulas HEp-2 foi de 275 ƒÊg mL-1 apos quatro dias de incubacao. Esses resultados indicam maior toxicidade contra os tripanossomas. O efeito inibitoriodo acido picolinico sobre o crescimento de

  17. Do We Need a Diet Therapy to Manage Patients with Chronic Kidney Disease in the Predialysis Period?

    OpenAIRE

    S.V. Kushnirenko

    2014-01-01

    The article examines the criteria for diagnosis of chronic kidney disease and the feasibility of diet therapy in combination with keto-analogues of essential amino acids at predialysis stage. It is proved that additional administration to the patients with predialysis chronic kidney disease of keto-analogues of essential amino acids enhances the metabolic beneficial effects of low-protein diet, promotes normalization of the amino acid composition of the blood and correction of metabolic acido...

  18. Evaluación de la mezcla de un prebiótico y un ácido orgánico en la salud intestinal y parámetros productivos de pollos de engorde

    OpenAIRE

    Jaramillo Benavides, Alvaro Hugo

    2011-01-01

    El objetivo del presente trabajó de investigación fue evaluar el efecto de un ácido orgánico (Acido fumárico) y un prebiótico comercial (Fortifeed®), y la combinación de éstos frente a un antibiótico promotor de crecimiento (Bacitracina de Zn) y un control, en el alimento de pollos de engorde, determinando los parámetros productivos y salud intestinal.

  19. Case-Detection Rate of Direct Sputum Smear Microscopy for ...

    African Journals Online (AJOL)

    de la culture sur milieu de Löwenstein- Jensen en tant que norme de référence . Sur les 150 participants testés, 51 étaient à frottis positif pour les bacilles acido rapide (taux de positivité, 34,0%, 51/150), tandis que 79 étaient positifs à la culture pour complexe Mycobacterium tuberculosis et 12 pour les mycobactéries non ...

  20. Case series

    African Journals Online (AJOL)

    2012-11-15

    Nov 15, 2012 ... L´agent pathogène est principalement le Mycobacterium tuberculosis ou le bacille de Koch secondairement le Mycobacterium bovis. Il s´agit d´un bacille acido-alcoolo-résistant à croissance lente (temps de dédoublement est de 15à 20 heures), ce qui explique l´évolution lente de la maladie. [5]. L´atteinte ...

  1. Lewis acid tuned facial stereodivergent HDA reactions using beta-substituted N-vinyloxazolidinones.

    Science.gov (United States)

    Gohier, Frédéric; Bouhadjera, Keltoum; Faye, Djibril; Gaulon, Catherine; Maisonneuve, Vincent; Dujardin, Gilles; Dhal, Robert

    2007-01-18

    The [4 + 2] acido-catalyzed heterocycloaddition between new beta-substituted N-vinyl-1,3-oxazolidin-2-ones (with R' = Me, Ar, CH2 Ar) and beta,gamma-unsaturated alpha-ketoesters (R = Ar) afforded heteroadducts with high levels of endo and facial selectivities. A complete reversal of facial differentiation was achieved by varying the Lewis acid, leading to the stereoselective formation of either endo-alpha or endo-beta adducts. [reaction: see text].

  2. Journal of Special Operations Medicine. Volume 9, Edition 4, Fall 2009

    Science.gov (United States)

    2009-01-01

    place in the evaluation, without full blood gas analysis, the body’s compensation mechanisms such as a respiratory alkalosis may maintain a normal or...sam- pling and relatively simple handheld diagnostic tools. Arterial pH has long been used to assess pa- tients for presence of respiratory /metabolic...acido- sis/ alkalosis . There is only a narrow physiologic range of intracellular pH which allows for normal function, typically 7.35-7.45. Acidosis

  3. The early irradiation syndrome. A study of the functional changes in the rabbit following whole-body γ exposure at sublethale doses

    International Nuclear Information System (INIS)

    Dufour, R.; Collignon, Y.; Vincent, F.

    1975-01-01

    A method of simultaneous observation of several physiological functions was developed in the unanaesthetized rabbit. Arterial blood pressure, local brain circulation, internal body temperature and arterial blodd acido-basic balance were thus followed before, during and after γ-irradiation. There appeared two periods in the development of this early syndrome: they were related to two processes, a central one, mainly of sympathetic origin was hardly sensitive to the dose, the other is dose-dependent [fr

  4. Variations au cours de la journée de l'incorporation in vivo de la leucine tritiée dans les protéines du cervelet et du cerveau du jeune rat normal et hypothyroïdien. Daily variations of the in vivo [3H] leucine incorporation into the cerebellar and cerebral proteins of the normal and hypothyroid young rat [(author's transl)].

    Science.gov (United States)

    Dainat, J; Rebière, A

    1978-02-15

    In the normal and hypothyroid 6-day-old rat, the specific radioactivity (RSA) and the relative RSA (ratio of the RSA to the [3H] lecine concentration of the acido soluble phase) of the cerebral and cerebellar proteins, changes during the day synchronally. They show a maximum at 15.00 h and a minimum at 0.300 h. At all stages studied, these values are significantly lower in the hyothyroid animals than in normal ones.

  5. Ensamble, diseño y ensayo de un potenciometro computarizado

    Directory of Open Access Journals (Sweden)

    Rocio Bojacá B.

    2010-05-01

    Full Text Available Se ha ensamblado una unidad potenciométrica (U.P. para mediciones de pH y fuerza electromotriz en procesos estáticos y de titulación. La reproducibilidad en mediciones de pH es de 0.013 unidades de pH y 0.01 mi en volumen. El potenciómetro consta de un acoplador de impedancias, un amplificador de ganancia variable y una interfase (convertidor análogico/Digital. El computador utilizado es un Kaypro II y et graficador es Phillips 8154. El software desarrollado incluye tos programas calibra (estandarización de la U.P. en dos pH diferentes, titula, tit140 y Tit1400 (titulaciones ácido-base y Redox y Ajus (cálculos de volimen como función de pH o potencial. En los ensayos de la U.P. se insiste en las diferencias que se observan en las gráficas cuando se titula un Acido Fuerte o un Acido Débil. En el primer caso se propone la denominación Zona Estabilizadora y en et segundo Zona Buffer o amortiguadora, donde se forma el típico sistema Acido/Sal.

  6. Residualidad del ácido sulfúrico aplicado como enmienda, y calculado de acuerdo con la CIC y con la suma de bases, sobre la estabilidad de los agregados en dos suelos salino-sódicos de la zona de Palmaseca, Valle del Cauca Residualidad del acido sulfúrico aplicado como enmienda, y calculado de acuerdo con la c 1c y con la suma de bases, sobre la estabilidad de los agregados en dos suelos salino-sódicos de la zona de palma seca, Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Charry Calle Jairo

    1988-12-01

    Full Text Available Los dos suelos salino-sódicos se cultivaron sucesivamente con algodón (Gossypium hirsutum var. Gossica P-21, soya (Glycine max var. ICA- Tunía y fríjol (Phaseolus vulgaris var. ICA- Gualí. La estabilidad de los agregados para los suelos, tratamientos y cultivos, se comparó calculando el área localizada debajo de cada una de las curvas aditivas porcentuales de los agregados, entre los parámetros menor de 025 mm y 0.42-0.84 mm.Residuality of sulfuric acid applied as amendment and calculated according to CEC and Sum of Exchangeable Bases (Ca, Mg, Na and K on the aggregate stability of two saline-sodic soils from Palmaseca zone , Cauca Valley, successively cultivated in cotton (Gossypium hirsutum var. Gossica P- 211. soybean (Glycine max var. ICA Tunía and bean (Phaseolus vulgaris var. ICA-Gualí was studied. The aggregate stability for two soils, treatments and crops, was compared by calculating the area located below each one of the accumulative percentage curves of aggregates, between less than 025 mm and 0.42-084 mm parameters. The results showed: A percent increase up to 56% in the aggregate stability of both soils, in treatments calculated according to CEC cultivated in soybean, and Sum of Exchangeable Bases cultivated in bean. The characteristic roots do not have a pronounced effect on aggregation. The initial and final chemical analysis of soils cultivated in cotton, bean and soybean showed in general, a 90 to 98% reductions of levels of sulphate, exchangeable sodium and exchangeable sodium percentage.

  7. Análise descritiva quantitativa do palmito de pupunheira Quantitative descriptive analysis of pejibaye palm heart

    Directory of Open Access Journals (Sweden)

    Marta Regina Verruma-Bernardi

    2007-01-01

    Full Text Available Este estudo foi conduzido para descrever o perfil sensorial do palmito de pupunha. A análise descritiva quantitativa (ADQ foi utilizada para descrever os atributos sensoriais relacionados à aparência, aroma, e textura de três marcas comerciais de palmito de pupunha. As amostras foram avaliadas por uma equipe selecionada com onze provadores e foram definidos nove atributos sensoriais: cor amarela, aparência uniforme e úmida, aroma e sabor não característicos, sabor acido, residual acido e textura macia. Houve diferenças significativas em seis atributos entre as três marcas testadas. Os provadores descreveram os palmitos de pupunha como: cor amarela clara, aparência uniforme e úmida, aroma e sabor não característicos e sabor ácido com valores intermediários, residual acido e amargor final com valores de pouco e textura muito macia a uma textura intermediária.This research was carried out to establish the sensory profile of pejibaye palm heart. The quantitative descriptive analysis was used to establish the sensory attributes related to appearance, flavor, taste and texture of tree commercial marks of pejibaye palm heart. These samples were evaluated by eleven trained panelists who described nine sensory attributes: yellow color, uniform and humid appearance, non-characteristic aroma and flavor, acid flavor, residual acid taste, and soft texture. There were significant differences in six attributes among the three tested marks. Panelists described the pejibaye palm heart as: light yellow color, uniform and humid appearance, non-characteristic aroma and flavor, acid flavor with medium values, acid residual taste and bitterness final taste from little values and high soft texture to an medium value texture.

  8. Modeling boron separation from water by activated carbon, impregnated and unimpregnated

    Energy Technology Data Exchange (ETDEWEB)

    Ristic, M.; Grbavcic, Z. [Belgrade Univ., Belgrade (BA). Faculty of Technology and Metallurgy; Marinovic, V. [Belgrade Univ., Belgrade (BA). Ist. of Technical Science of the Serbian Academy of Science and Arts

    2000-10-01

    The sorption of boron from boric acid water solution by impregnated activated carbon has been studied. Barium, calcium, mannitol, tartaric acid and citric acid were used as chemical active materials. All processes were performed in a chromatographic continuous system at 22{sup 0} C. Experimental results show that activated carbon impregnated with mannitol is effective in removing boron from water. The separation of boron from the wastewater from a factory for producing enameled dishes by activated carbon impregnated with mannitol was also performed. Two models have been applied to describe published and new data on boron sorption by impregnated activated carbon. Both of them are based on the analysis of boron concentration response to the step input function. This led to a mathematical model that quite successfully described impregnation effects on adsorption capacities. [Italian] E' stato studiato l'assorbimento del boro, mediante carbone attivo impregnato, da soluzioni acquose di acido borico. Quali materiali chimici attivi sono stati utilizzati: bario, calcio, mannitolo, acido tartarico ed acido citrico. Tutti i processi sono stati condotti in un sistema cromatografico continuo a 22{sup 0}C. I risultati sperimentali mostrano che il carbone attivo impregnato con mannitolo e' efficace nella rimozione del boro dall'acqua. E' anche stata effettuata la separazione del boro da acque di scarico di un'industria per la produzione di piatti smaltati mediante carbone attivo impregnato con mannitolo. Sono stati applicati due modelli per descrivere i risultati, pubblicati e nuovi, dell'assorbimento del boro mediante carbone attivo impregnato. Entrambi sono basati sull'analisi della risposta alla concentrazione di boro successivamente incrementata a stadi. Cio' porta ad un modello matematico che descrive abbastanza soddisfacentemente gli effetti dell'impregnazione sulla capacita' di assorbimento.

  9. Temas de bioquímica básica (DIAPOSITIVAS)

    OpenAIRE

    Correa Quiroz, Jorge Alberto

    2003-01-01

    A continuación se da a conocer el trabajo preparado y organizado por el docente Jorge Alberto Correa Quiroz durante el periodo de su año sabático, los temas a exponer son: Metabolismo y bioenergética, Metabolismo de carbohidratos, Ciclo del acido cítrico y del glioxilato, Transporte de electrones y fosforilación oxidativa, Metabolismo de lípidos y ácidos grasos, metabolismos del amoniaco y compuestos nitrogenados, Fotosíntesis. / Abstract. Then we explain the work planned and organized by...

  10. Neodymium nitrate-tetraethylammonium nitrate-water system

    International Nuclear Information System (INIS)

    Khisaeva, D.A.; Boeva, M.K.

    1987-01-01

    Method of isothermal cross sections at 25 and 50 deg C is used to study solid phase solubility in the neodymium nitrate-tetraethylammonium nitrate-water system. Crystallization fields of congruently soluble compounds, the salt component ratio being 1:1:4H 2 O and 1:3:2H 2 O are detected. New solid phases are preparatively obtained and subjected to chemical, differential thermal, IR spectroscopic and X-ray diffraction analyses. The obtained compounds are acido-complexes in which nitrate groups enter into the first coordination sphere

  11. Química de especies del genero espeletia Espeletia killipii - Espeletia tunjana

    Directory of Open Access Journals (Sweden)

    Rubén Darío Torrenegra

    2010-07-01

    Full Text Available De las partes aéreas de 2 especies del género Espeletia se aislaron compuestos del tipo diterpeno Acido (-i-Kaur-9( 11, 16-dien-19-oico, el (-Kaur-16-en-19-ol, los terpenos friedeiina, sitosterol-estigmasterol, y dos sesquiterpenlactonas del tipo melampólido, Acetato de Longipilin y Polimatin B. Los últimos compuestos no reportados hasta el momento en la química del género Espeletia. Del extracto etanólico se identificaron dos flavonoides: Quercetina y 3-metoxiquercetina.

  12. Diseño de una planta de producción de ácido l-glutamático a partir de melazas de remolacha azucarera

    OpenAIRE

    San José García, Pablo

    2014-01-01

    INTRODUCCIÓN El ácido L-glutámico es uno de los aminoácidos con mayor demanda a nivel mundial, su producción supera los 1,5 millones de toneladas al año. Es un precursor de Glutamato Monosódico el cual es bastamente utilizado en la industria alimentaria como aditivo saborizante. En el Presente proyecto de fin de carrera se realiza un diseño preliminar de una Planta de producción de acido glutámico por la via fermentativa , utilizando como microorganismo a la bacteria ...

  13. Impacto del arsénico en yacimientos auríferos

    OpenAIRE

    Hidalgo Velazco, María del Rosario; Hidalgo Velazco, María del Rosario

    2006-01-01

    El presente trabajo tiene por objeto expresar los mecanismos naturales de generación del arsénico en la minería su movilidad y su solubilidad en ambientes acuosos como el Drenaje Acido de Roca (DAR) y agua de los ríos. Para lo cual se plantea alternativas de remoción y mitigación del arsénico en diferentes escalas de caudal, para aguas que satisfagan la Ley General de Aguas (LGA) clase III y la ley del agua potable. The present thesis trys to explain the natural process for Acid Drainage c...

  14. Protometric thermometric titrations of sparingly soluble compounds in water in the presence of n-octanol.

    Science.gov (United States)

    Burgot, G; Burgot, J-L

    2002-10-15

    Thermometric titrimetry permits titration of acido-basic compounds in water in the presence of n-octanol. n-Octanol permits the solubilization of protolytes and moreover may also displace the equilibria of the titration reactions. Hydrochlorides of highly insoluble derivatives such as phenothiazine derivatives can be titrated with satisfactory accuracy and precision by sodium hydroxide despite their high pK(a) values. Likewise barbiturate salts can be titrated by hydrochloric acid. In the case of some salts, the methodology may permit the sequential titration of the ion and counter ion. Copyright 2002 Elsevier Science B.V.

  15. Soil decontamination at the Montevecchio-Levante mine site with experimental washing and leaching techniques

    Energy Technology Data Exchange (ETDEWEB)

    Dessi, R. [Progemisa SpA, Cagliari (Italy); Fadda, S.; Peretti, R.; Zucca, A. [CSGM, Centro Studi Germinerari e Mineralurgici del CNR, Cagliari (Italy); Serci, A. [Digita, Dipt. di Geoingegneria e Tecnologie Ambientali, Cagliari (Italy)

    2000-12-01

    The soils in the neighbourhood of the Rio Montevecchio-Sitzerri, a stream that flows in the valley below the tailings pond of the Montevecchio-Levante mineral processing plant (SW Sardinia, Italy) are severely contaminated by heavy metals, to the extent that traditional land uses are compromised. Consequently urgent measures are needed both to abate the pollution at source and rehabilitate the contaminated land. This paper is concerned with the problem of soil decontamination using washing and leaching techniques. Laboratory experiments have been conducted in mechanically agitated reactors, using citric acid and acetic acid solutions and brine of hydrochloric acid and calcium chloride. The influence of both reagent concentration and solid-to-liquid ratio has been assessed, and in the most significant cases, the attack kinetics has been determined. The tests showed the brine to be the most effective for removing metals from the soils. Based on the findings of the investigations, the possibility of decontamination by heap leaching has been simulated in the laboratory using the column technique. [Italian] I suoi circostanti il Rio Montevecchio-Sitzerri, che scorre a valle del bacino di decantazione degli sterili dell'impianto di trattamento dei minerali di Montevecchio-Levante (Sardegna Centro-Occidentale), sono caratterizzati da un elevato contenuto di metalli pesanti, che ne pregiudicano gli usi tradizionali. Si rende percio' improrogabile sia la necessita' di intervenire sulle cause all'origine della contaminazione, sia di bonificare i suoli in questione al fine di recuperarli a nuovi usi. La memoria intende portare un contributo alle relative problematiche affrontando la possibilita' di decontaminazione mediante tecniche di lavaggio e lisciviazione. La sperimentazione di laboratorio e' stata condotta in reattori ad agitazione meccanica, utilizzando soluzioni con acido citrico, acido acetico ed una salamoia costituita da acido

  16. Sintesi, modifica e caratterizzazione di polimeri da fonti rinnovabili

    OpenAIRE

    Cruciani, Letizia

    2013-01-01

    Gli argomenti trattati all’interno di questa tesi di dottorato riguardano la sintesi e la modifica di polimeri ottenuti a partire da fonti rinnovabili. L’acido polilattico (PLA) è stato modificato per ottenere film estensibili per uso alimentare. La scelta del materiale si è basata sull’analisi del suo ciclo di vita e perché è riconosciuto come sicuro per l’utilizzo nel campo alimentare. Le formulazioni testate, a base di PLA, sono state preparate con l’aggiunta di una serie di additivi u...

  17. EFECTO DEL ÁCIDO CLORHÍDRICO Y LA TEMPERATURA EN LA MORFOLOGÍA DE PIEZAS DENTARIAS SANAS. AREQUIPA. 2014

    OpenAIRE

    LOVÓN QUISPE, WASHINGTON EDWARD

    2015-01-01

    TABLAS DE MORFOLOGIA DE LAS PIEZAS DENTARIAS SANAS SOMETIDAS A LA ACCION DEL ACIDO CLORHIDRICO TABLAS DE MORFOLOGIA DE LAS PIEZAS DENTARIAS SANAS SOMETIDAS A LA ACCION DE LA TEMPERATURA LA IDENTIFICACIÓN FORENSE LOS DIENTES ELEMENTOS ARQUITECTÓNICOS DE LOS DIENTES ESTRUCTURA DEL DIENTE EL ESMALTE CARACTERÍSTICAS GENERALES DEL ESMALTE ESTRUCTURA DEL ESMALTE LA DENTINA CARACTERÍSTICAS GENERALES DE LA DENTINA COMPOSICIÓN QUÍMICA DE LA DENTINA EL CEMENTO EL ÁCIDO CLORHÍDRICO RIESGOS DEL ÁCIDO CLO...

  18. Síntesis y caracterización espectroscópica de sulfatos de hierro: implicaciones en astrobiología y la exploración de Marte

    OpenAIRE

    Sansano Caramazana, Antonio

    2015-01-01

    Hay una serie de aspectos que fundamentan la necesidad y el interés de las investigaciones que en este proyecto de tesis se recogen. Por un lado, el interés por los sulfatos de hierro. Estos sulfatos tienen unas características físico químicas y estructurales que suponen un autentico mundo a descubrir y describir, con variadas composiciones, variados comportamientos acido-base y redox, diferentes grados de hidratación y diferentes disposiciones estructurales para mismas composiciones. La ...

  19. Multímetro como sistema de medición alternativo en las valoraciones potenciométricas

    Directory of Open Access Journals (Sweden)

    José de Jesús Pérez-Saavedra

    2015-09-01

    Full Text Available En el presente trabajo, experimentalmente se demuestra que las valoraciones potenciométricas usuales en química analítica (acido-base, redox, complejométricas y de halogenuros pueden llevarse a cabo utilizando como sistema indicador de punto de equivalencia, un multímetro en vez del potenciómetro, mediante la prueba estadística de t de Student; y se posibilita con esto que los laboratorios de docencia se puedan equipar mejor y a bajo costo, con multímetros en vez de potenciómetros.

  20. Estudio de la síntesis de acetato de butilo 4—cinética de reacción

    OpenAIRE

    Orjuela Londoño, Álvaro; Leiva Lenis, Fernando; Boyacá Mendivelso, Luis Alejandro; Rodríguez Niño, Gerardo; Carballo Suárez, Luis María

    2010-01-01

    En este trabajo se adelantó un estudio de la reacción de esterificación de acido acético y n-butanol en fase líquida (P = 0,76 Bar), utilizando unas resinas de intercambio catiónico (Lewatit K-2431) como catalizador. Se estableció la ausencia de efectos de transferencia de masa dentro y fuera de las partIculas de catalizador en las condiciones estudiadas. Se efectuaron ensayos para determinar la influencia de la carga del catalizador (0.5 %,1%, 2% p/p), la temperatura (73°C, 80°C, 87...

  1. Inspección visual con ácido acético (IVAA) en la detección precoz del cancer de cuello uterino :

    OpenAIRE

    Foresi, Ana María del Valle

    2009-01-01

    Tesis Doctor en Medicina y Cirugía -- Universidad Nacional de Córdoba. Facultad de Ciencias Médicas. La Inspección Visual con Acido Acético (IVAA) constituye una alternativa frente a la citología Exfoliativa en el examen de detección del cuello de útero en lugares de escasos recursos o como complemento de papanicolaou en zonas de mediano recursos. OBJETIVOS: Examinar la sensibilidad, especiaficidad, valor predictivo positivo y negativo de los tres métodos de pesquisa (inspección visual con...

  2. Cadmium complexes with 1,2-dimethylbenzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Slyusarenko, K F; Artemenko, M V; Pokhodnya, G A [Kievskij Tekhnologicheskij Inst. Pishchevoj Promyshlennosti (Ukrainian SSR)

    1982-02-01

    New coordination complexes of Cd(2) with 1, 2 - dimethylbenzimidazole (DMBI) of the composition DMBIxCdX/sub 2/, where X=Cl, Br, I and 2DMBIxCdX/sub 2/, where X=NO/sub 3/, CH/sub 3/COO, SCN as well as acido-complexes of the composition (DMBIH)xCdX/sub 4/ (X=Cl, Br) are synthesized. IR-spectra, diffraction diagrams and curves of radial distribution of atomic density for coordination halides and for the rhodanide complex are investigated. Conclusions on individuality and structure of the compounds obtained are made.

  3. Valoraci??n del estatus de tiamina en un colectivo andaluz y su relaci??n con otros par??metros

    OpenAIRE

    Garc??a-??vila, M.; Florea, Daniela Ioana; Mill??n, E.; S??ez P??rez, Laura; Molina-L??pez, Jorge; G??lvez, A.; L??pez-Gonz??lez, B.; Planells del Pozo, Elena Mar??a

    2010-01-01

    INTRODUCCI??N: Las vitaminas del grupo B (piridoxina, riboflavina, cianocobalamina, acido f??lico, etc.) se relacionan estrechamente como componentes de coenzimas que intervienen en procesos de obtenci??n de energ??a para llevar a cabo reacciones metab??licas b??sicas para el organismo como el ciclo de Krebs, el ciclo de pentosa-P, etc... La vitamina B1 es, en ocasiones, desestimada de la lista de sustancias valoradas en una determinada poblaci??n, por descartar la posible deficie...

  4. Determinação de ferro (III em produtos farmacêuticos por titulação fotométrica = Determination of iron (III in pharmaceutical products by photometric titration

    Directory of Open Access Journals (Sweden)

    Airton Vicente Pereira

    2011-01-01

    Full Text Available Este trabalho descreve a montagem de um sistema de titulacao fotometrica simples e de baixo custo para a determinacao de ferro (III em produtos farmaceuticos. O sistema de titulacao fotometrica foi construido utilizando-se a bomba peristaltica de um espectrofotometro convencional. O procedimento e baseado na titulacao de ferro (III com EDTA e acido salicilico como indicador. A absorcao do complexo ferro (III-acido salicilico foi monitorada espectrofotometricamente em 525 nm. O limite de quantificacao foi de 5 ƒÝg de ferro (III. O procedimento de titulacao fotometrica foi aplicado para a determinacao de ferro (III em amostras contendo sulfato ferroso e hidroxido ferrico polimaltosado. O procedimento mostrou sensibilidade, reprodutibilidade e precisao para a utilizacao em analise rotineira de ferro (III em produtos farmaceuticos.This paper describes a simple, precise and low-cost photometrictitration method for iron (III determination in pharmaceutical preparations. The photometric titration system was constructed using the peristaltic pump of a conventional spectrophotometer. The method is based on titration of iron (III with EDTA using salicylic acid as indicator. The absorption of the iron (III-salicylic acid complex wasmonitored spectrophotometrically at 525 nm. The limit of quantification was 5 ƒÝg of iron (III. The photometric titration procedure was applied for the determination of iron (III in samples of ferrous sulfate and ferric hydroxide polymaltose complex. The procedure showed sensibility, reproducibility and accuracy for use as a method for the routine analysis of iron (III in pharmaceutical formulations.

  5. Efecto sobre la viabilidad celular de una nueva serie de espirosteroides sintéticos en células PC12

    Directory of Open Access Journals (Sweden)

    Laura García-Pupo

    2013-03-01

    Full Text Available Introducción: la diosgenina y sus derivados se han descrito como potentes inhibidores de la proliferación en varias líneas tumorales. Sin embargo otras moléculas relacionadas estructuralmente con dichos derivados, se han reportado como candidatos terapéuticos y otras de ellas se incluyen en alimentos de consumo humano. Objetivo: el presente trabajo evalúa el efecto sobre la viabilidad celular de una nueva serie de espiroesteroides sintéticos derivados de la diosgenina, en células tipo neurales PC12. Métodos: la viabilidad de los cultivos de PC12 se determinó mediante el ensayo de MTT y se calcularon descriptores moleculares teóricos como la lipofilicidad (logP virtual y la superficie de área polar (SAP, con el objetivo de establecer relaciones estructura-actividad. Resultados: nuestros resultados demuestran que solo el acido taurodesoxicólico disminuye de manera significativa la viabilidad celular. Más aun, dicha molécula presenta valores menores y mayores de logP virtual y SAP, respectivamente, respecto al resto de los esteroides de la serie. Conclusiones: los resultados anteriores avalan el estudio del acido taurodesoxicólico como potencial inhibidor de la proliferación celular y al resto de las moléculas de la serie como candidatos neuroprotectores a evaluar en esta misma línea celular y dosis de tratamiento.

  6. Synthesis and characterization of magnetic nanoparticles of oxides for dual MnFe{sub 2}O{sub 4} bioseparation, stabilized in fatty acid and the system chitosan - Eu(TTA){sub 3}(TPPO){sub 2}. Studies on the influence of doping with Gd{sup 3+}, Tb{sup 3+}, Ho{sup 3+} e Eu{sup 3+} in structural and magnetic properties; Sintese e caracterizacao de nanoparticulas magneticas de oxidos duplos de MnFe{sub 2}O{sub 4} para biosseparacao, estabilizadas em acido graxo e recobertas pelo sistema quitosana - Eu(TTA){sub 3}(TPPO){sub 2}. Estudo da influencia da dopagem com Gd{sup 3+}, Tb{sup 3+}, Ho{sup 3+} e Eu{sup 3+} nas propriedades estruturais e magneticas

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, Thelma Antunes Rodrigues

    2014-07-01

    This work was synthesized and characterized ferrite magnetic nanoparticles manganese, using the chemical coprecipitation method. By varying the heating time under 98°C (0, 10,20,40,60 3 80 minutes), the molar percentage of doping (1, 3, 5, 7, and 10%), gadolinium, europium, terbium and holmium. Magnetic ferrite nanoparticles and manganese ferrite doped with manganese were synthesized by coprecipitation method starting with chloride solutions of metals (iron (III), manganese (II), europium (III), gadolinium (III), terbium (III) and holmium (III)) and NaOH 5mol.L{sup -1} as precipitating agent. The magnetic nanoparticles were characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, magnetization curves, and thermal analysis. Most of manganese ferrite particles showed superparamagnetic behavior. After the characterization it was found that the samples synthesized manganese ferrite with more than 40 minutes heating time, crystal structure showed the characteristic pattern of the inverted manganese ferrite spinel type. The stabilization of the samples in oleic acid nanoparticles produced with a hydrophobic outer layer and facilitated by coating chitosan biopolymer, since this has a positive charge. Among the doped samples there was no significant change in the magnetic behavior. Several techniques for characterizing these materials have been used such as X-ray diffraction spectrum in the infrared region, magnetization curves and thermal analysis. The resins were tested as magnetic material for the separation of biological materials. In this paper, are used as biological targets separation of bovine serum albumin. (author)

  7. Regeneracion adventicia de somaclones de uchuva (Physalis peruviana

    Directory of Open Access Journals (Sweden)

    Santana Gloria E.

    1997-06-01

    Full Text Available

    Hipocoti1os de uchuva (Physalis peruvjana L. fueron utilizados en la inducción de callos y regeneración de plántulas. El medio basal de Murashige y Skoog (MS fue suplementado con bencil amino purina (BAP de 0 a 5,0 ppm, acido giberelico (GA3 0 Y 1,0 ppm en combinacion con acido naftalenoacetico (ANA de 0 a 1.0 ppm o con acido 2,4 diclorofenoxiacetico (2,4-D  de 0 a 1.0 ppm. La inducción de callos dependió de las interacciones hormonales y condiciones de luz. La regeneración de plántulas en medias que contenían ANA o cuando el medio no fue suplementado  con 2,4-D fue nula o muy poca. EI mayor numero de plántulas regeneradas fue observado en medios complementados con 1.0 ppm de BAP, 1,0 ppm de GA y 0,5 ppm de 2,4-D en condiciones de luz. Las plántulas regeneradas fueron micropropagadas en el medio basal de MS sin ningún suplemento hormonal. Finalmente, las plantas se evaluaron in vitro bajo condiciones de heladas simuladas.

    Palabras claves: Variaci6n somaclonal, inducción de callos morfogénesis indirecta, cultivo in vitro.

  8. Supported liquid membrane stability in chiral resolution by chemically and physically modified membranes

    Energy Technology Data Exchange (ETDEWEB)

    Molinari, R.; Argurio, P. [Arcavata di Rende Univ. of Calabria, Arcavata di Rende, CS (Italy). Dept. of Chemical and Materials Engineering

    2001-04-01

    In the present work some stability studies on Supported Liquid Membranes (SLMs) to be used for chiral separations were realized. In particular, primary aim was to determine how a modification of the support surface influences the SLM stability. First, the procedure for support modification was optimised, making a screening of various compounds (sulphuric acid, nitric acid, chromic acid, sodium dodecyl sulphate (SDS), glycerol, oleic alcohol, propylene glycol (PPG), bovine serum albumin (BSA)) and testing their performance by means of contact angle measurements. Next, a second screening was realized by permeation tests in a stirred cell. Finally, to compare the stability of modified with unmodified support in a process of interest for chemical and/or biochemical industries, some permeation tests for resolution of DNB-DL-Leucine were realized in a re-circulation system. Results showed a better surface hydrophilization of chemically modified support and better stability of the sulphonated support. However, in operating conditions a little high stability of the unmodified support was obtained. [Italian] Nel presente lavoro sono stati realizzati degli studi di stabilita' di Membrane Liquide Supportate (SLMs) da impiegare in separazioni chirali. In particolare, obiettivo principale e' stato quello di determinare l'influenza che una modifica della superficie del supporto ha sulla stabilita' della SLM. Cosi', in un primo momento, e' stata ottimizzata le procedura di modifica del supporto, facendo una selezione tra vari composti (acido solforico, acido nitrico, acido cromico, sodio dodecil solfato (SDS), glicerolo, alcool oleico, glicole propilenico (PPG), siero di albumina bovina (BSA)) basata su misure dell'angolo di contatto. Successivamente, e' stata realizzata una seconda selezione mediante prove di permeazione in una cella agitata. Infine, con lo scopo di confrontare la stabilita' della SLM con supporto modificato rispetto

  9. Tuberculose pulmonaire révélée par un purpura thrombopénique chez l'enfant-à propos d'un cas clinique observé au service de pédiatrie des Cliniques Universitaires de Lubumbashi

    Science.gov (United States)

    Lubala, Toni Kasole; Mutombo, Augustin Mulangu; Munkana, Arthur Ndundula; Manika, Michel Muteya

    2012-01-01

    Nous rapportons le cas d'un enfant de 7 ans, de sexe masculin ayant présenté un purpura thrombopénique avec épistaxis, hématémèse, otorragies et pétéchies généralisées. Durant la même hospitalisation, nous avons mis en évidence une tuberculose pulmonaire documentée par la présence de bacilles acido-alcoolo résistants à l'examen des crachats. Nous avons observé une majoration du taux de plaquettes en une semaine de corticothérapie intraveineuse à haute dose, avant l'instauration d'une poly chimiothérapie antituberculeuse. Nous rappelons également la controverse que suscite la prise en charge de cette association rarement rapportée. PMID:23077696

  10. Homocisteína como fator de risco para doenças cardiovasculares

    Directory of Open Access Journals (Sweden)

    Sthefano Atique Gabriel

    2007-05-01

    Full Text Available Elevadas concentrações plasmáticas de homocisteína têm sido identificadas como um fator de risco independente para aterosclerose cerebral, coronariana e periférica. Os efeitos danosos da homocisteína sérica são fruto de suas características aterogênicas e trombogênicas. O tratamento mais eficaz para hiperhocisteinemia consiste na redução da homocisteína plasmática, através da fortificação alimentar com suplementos vitamínicos, ricos em vitamina B6, vitamina B12 e, principalmente, acido fólico. A dose recomendada é de 400 microgramos de folato por dia, sendo esta medida uma poderosa redutora da morbidade e mortalidade cardiovascular, além de prevenir possíveis defeitos de fechamento do tubo neural.

  11. Caracterización de los ácidos húmicos extraídos de cuatro lombricompuestos y su efecto sobre la germinación de semillas de maíz Zea mays L., algodón Gossypium hirsutum y tomate Lycopersicon esculentum L.

    Directory of Open Access Journals (Sweden)

    Gómez Zambrano Jairo

    1996-12-01

    Full Text Available

    The work perfomed to characterize the elemental composition and functional groups of humic acids extracted from four lombricompost cow dung, filter press cake of sugar cane, coffee pulp and grass residue the total content of essential elements and its distribution in the humic and no humic fractions were determined. It was evalued the effect of two concentrations of humic acids (150 and 300 ppm upon seed germination of maize, cotton and tomat. There were found differences in the elemental composition (CHON and functional groups (COOH, OH phedic and carbony of the humic acids atributed to variations in composition of the original substrates. The lombricompost of cow dung showed higher oxidation values (O/H = 0.49 than the lombricompost of filter press cake of sugar cane (0.40 sugering a higher grade of humification of the first. The grass residue showed higher contribution to the CIC (COOH + OH = 9. O me/g than the coffe pulp (7. 1 me/g the total essential elements were concentrated in the remanent residue, with lower content in the water and 0.1M HCL solutions; the fulvic and humic fractions had very low content of these elements. The humic acid at the concentrations tested did not have any effect on the germination of maize and cotton, and depressed the germination of tomato seeds.

    El trabajo se realizó con el fin de caracterizar por su composición elemental y contenido de grupos funcionales, los acidos húmicos extraídos de cuatro lombricompuestos (bovinaza, cachaza, pulpa de café y residuo de prado. Se determinó el contenido y distribución de los elementos esenciales totales en las fracciones húmicas y no de acidos húmicas. Se evaluó el efecto de dos concentraciones de acidos húmicos (150 y 300 ppm sobre la germinación de semillas de maíz, algodón y tomate. Se encontraron diferencias en el contenido elemental (CHON y grupos funcionales (COOH, OH fenólico y carbonilo atribuido a variaciones en la composición de los

  12. Role of central nervous system in acute radiation syndrome functional metabolic encephalopathy

    International Nuclear Information System (INIS)

    Court, L.; Fatome, M.; Gueneau, J.; Rouif, G.; Pasquier, C.; Bassant, M.H.; Dufour, R.

    In adult rabbit, the effect on the brain of a whole-body or encephalic gamma irradiation is a function of the absorbed dose and begins after 25 rads. Three phases are described in the mechanism of radiation effect. In the initial phase, irradiation acts as a direct stimulus of cerebral structures. The second phase is a response towards aggression which includes: the effect of stimulation of various cerebral structures; their response and the induced feed-back mechanism; the release of metabolites inducing a functional metabolic encephalopathy in which occur: modification of blood pressure; modification of pulmonary ventilation; modification of acido-basic blood equilibrium. The third phase consists of functional recovery [fr

  13. Development of an acoustic emission equipment for valves of the Nuclear Power Station Atucha 1

    International Nuclear Information System (INIS)

    Giaccheta, R.; Lopez Pumarega, I.; Straus, A.; Ruzzante, J.; Herzovich, P.

    1994-01-01

    A four channel Acoustic Emission was developed by the Acoustic Emission Group, INEND Department, of the Atomic Energy Commission of Argentina, for the detection of leaks in valves of the pressurized air system: ''Sistema de desconexion de emergencias por acido deuteroborico''. Basically, the system consists of four piezoelectric transducers with their corresponding preamplifiers coupled to the piping close to the valves. The following stages: amplifiers, threshold levels, channel identifications and visual alarm system are gathered in a box. The system was installed in the controlled zone of the Nuclear Power Stations Atucha I. It was calibrated and works on line. The values shown on the display are registered daily in order to separate the normal values from the leak ones. (author). 4 refs, 9 figs

  14. Activity and stability of a <> oxynitride in the dehydrogenation of isobutane

    Energy Technology Data Exchange (ETDEWEB)

    Delsarte, S.; Grange, P. [Univ. Catholique de Louvain (Belgium). Unite de Catalyse et Chimie des Materiaux Divises; Laurent, Y. [Lab. de Chimie des Materiaux, Univ. de Rennes 1, Rennes (France)

    2000-07-01

    Isobutane dehydrogenation was studied on platinum impregnated mixed aluminium gallium phosphorus oxide and oxynitride, in a continuous, flow micro-reactor at 500-550 C. Comparison of the <> and <> shows the importance of nitridation on the acido-basic properties of the catalyst. A deactivation of the catalyst, due to the deposition of carbonaceous species on the surface, was observed. As the properties of the oxynitride would be altered by a regeneration treatment at high temperature with flowing oxygen, the possibility of decreasing the deactivation rate by decreasing the reaction temperature and by adding hydrogen to the reactant mixture was explored. Catalytic tests, carried out at different hydrogen partial pressures, showed that the hydrogen inhibits the carbon deposition on the surface of the catalyst and thus increases the catalytic stability. (orig.)

  15. Contribution of cellular automata to the understanding of corrosion phenomena

    Directory of Open Access Journals (Sweden)

    M. Zenkri

    2017-09-01

    Full Text Available We present a stochastic CA modelling approach of corrosion based on spatially separated electrochemical half-reactions, diffusion, acido-basic neutralization in solution and passive properties of the oxide layers. Starting from different initial conditions, a single framework allows one to describe generalised corrosion, localised corrosion, reactive and passive surfaces, including occluded corrosion phenomena as well. Spontaneous spatial separation of anodic and cathodic zones is associated with bare metal and passivated metal on the surface. This separation is also related to local acidification of the solution. This spontaneous change is associated with a much faster corrosion rate. Material morphology is closely related to corrosion kinetics, which can be used for technological applications.

  16. Zinc and cadmium monosalicylates

    International Nuclear Information System (INIS)

    Kharitonov, Yu.Ya.; Tujebakhova, Z.K.

    1984-01-01

    Zinc and cadmium monosalicylates of the composition MSal, where M-Zn or Cd, Sal - twice deprotonated residue of salicylic acid O-HOC 6 H 4 COOH (H 2 Sal), are singled out and characterized. When studying thermograms, thermogravigrams, IR absorption spectra, roentgenograms of cadmium salicylate compounds (Cd(OC 6 H 4 COO) and products of their thepmal transformations, the processes of thermal decomposition of the compounds have been characterized. The process of cadmium monosalicylate decomposition takes place in one stage. Complete loss of salicylate acido group occurs in the range of 320-460 deg. At this decomposition stage cadmium oxide is formed. A supposition is made that cadmium complex has tetrahedral configuration, at that, each salicylate group plays the role of tetradentate-bridge ligand. The compound evidently has a polymer structure

  17. Herbicides synthesis and biological tests to determine its activity on the weeds; Sintesis de herbicidas y pruebas biologicas para determinar su actividad sobre la maleza

    Energy Technology Data Exchange (ETDEWEB)

    Romero M, Artemisa [Universidad Autonoma Metropolitana-Xochimilco, Mexico, D. F. (Mexico); James M, Guillermo [Universidad Autonoma Metropolitana-Xochimilco, Mexico, D. F. (Mexico); Miramontes F, Benjamin [Universidad Autonoma Metropolitana-Xochimilco, Mexico, D. F. (Mexico); Haro C, Jorge [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D.F. (Mexico)

    1995-02-01

    Four derivatives of Dicamba (2-methoxy-3, 6-dichlorobenzoic acid) were obtained: 2-methoxy-3, 6-dichlorobenzyl alcohol, 2-methoxy-3, 6-dichlorobenzaldehyde, 2-methoxy-3, 6-dichlorobenzaldoxime, tested on weed, and 2-methoxy-3, 6-dichlorobenzylamine. The weeds were Taraxacum officinale Weber, Amaranthus silvester and Sonchus oleraceus L. The oxime did not show activity on Amaranthus silvester, all the substances were active on the other two weeds. [Spanish] Se sintetizaron cuatro derivados del herbicida Dicamba (acido 2-metoxi-3, 6-diclorobenzoico), y se hicieron pruebas de la actividad de tres de ellos sobre maleza de Xochimilco. Se probaron el alcohol 2-metoxi-3, 6-diclorobencilico, 2-metoxi-3, 6-diclorobenzaldehido, 2-metoxi-3, 6-diclorobenzaldoxima. La maleza fue Taraxacum officinale Weber (Diente de leon), Amaranthus silvester (Amaranto silvestre) y Sonchus oleraceus L. (Sonchus). En amaranto, la oxima fue el unico que no presento actividad. En diente de leon y Sonchus, todas las sustancias probadas presentaron actividad.

  18. Curvas de titulación potencio métrica ácido-base de una bentonita

    OpenAIRE

    Pinilla Cuenca, Liz Adriana; Pinzón Bello, Jorge Alejo

    2011-01-01

    Se estudió el comportamiento acido- base de una bentonita colombiana proveniente del Valle del Cauca, medianteexperimentos de titulación potenciométrica. Se escogió el método de titulación por retroceso, ya que la técnica de titulación continua no produce una curva única de valoración.La curva de titulación muestra tres puntos de inflexión, establecidos mediante los máximos en la curva derivada, envalores de pH de 4,8; 6,2 y 6,8, que indican tres tipos de sitios ácidos, identificados con los ...

  19. Concordancia entre métodos de valoración de imbalance del estado ácido-base en la unidad de cuidado intensivo pediátrico

    OpenAIRE

    López Cubillos, Juan Francisco

    2013-01-01

    Las alteraciones del estado ácido base son comunes en los pacientes en estado crítico y se consideran marcador tanto de gravedad como de pronóstico. (1,2) Existen varios métodos de valoración del estado acido base. El primero es el tradicional denominado aproximación de Henderson-Hasselbach (HH) el cual basa los cambios de pH en la concentración de bicarbonato y la presión de CO2 en el organismo. El segundo es la aproximación de Stewart que se basa en el concepto de electro-neutralidad y en l...

  20. Alguns aspectos químicos, físico-químicos e estruturais da mucilagem extraída de folhas de Pereskia aculeata Mill

    OpenAIRE

    Sierakowski, Maria Rita, 1953-

    2013-01-01

    Resumo: O pó atônico tratado com benzeno-etanol (2:1, v/v) de folhas de Pereskia aculeata, foi submetido a exaustiva extração com água quente e o extrato, após precipitação etanólica, forneceu um heteropolissacarídeo mucilaginoso. Após sucessivas desproteinizações, pelo método de Sevag, o polímero apresentou 36,01 de acucar total e a seguinte composição: ramnose, 9,2%; fucose, 2,5%; ribose, 2,51; arabinose, 27,51; xilose, 2,5%; manose, 3,0%;ga lactose, 40,8%, glucose, 3,0%, acido-D-galacturo...

  1. Safe and quick carbon sequestration

    International Nuclear Information System (INIS)

    Tiano, M.

    2016-01-01

    Geological sequestration of carbon dioxyde is considered as an important tool to fight global warming but long term safety is an essential issue due to the risk of accidental leakages. The CarbFix experimentation has shown the possibility to turn hundreds tons of CO 2 into inert carbonated rocks in less than 2 years. This CO 2 injection took place in basaltic rocks. Basaltic rocks allows an adequate diffusion of the gas because of its porosity and favors the acido-base chemical reaction that turns CO 2 into inert and stable carbonates. This experiment was performed with CO 2 dissolved in water in order to limit leaks, basaltic layers being naturally cracked, and to accelerate the formation of carbonates by dissolving the metal ions coming from the rocks. The important quantity of water required for this technique, limits its use to coastal sites. (A.C.)

  2. KINETIC STUDY OF PALMITIC ACID ESTERIFICATION CATALYZED BY Rhizopus oryzae RESTING CELLS

    Directory of Open Access Journals (Sweden)

    JONH J MÉNDEZ

    2009-01-01

    Full Text Available ABSTRACT In the present study, a kinetic model for the biocatalytic synthesis of esters using Rhizopus oryzae resting cells is proposed. The kinetic study has been made in a range of 30-50 °C and atmospheric pressure. The Influence of operating variables, water content, pH, amount of mycelium was studied. Different values of temperature, initial mycelium concentration and acid/alcohol molar ratio were tested. Initial rates were estimated from the slope of the concentration of palmitic acid, or their corresponding ester at conversions of less than 10%, versus time and reported as mmol l-1 min -1. The values of kinetic constants were computed using the freeware program SIMFIT (http:\\\\www.simfit.man.ac.uk. Key words: bound lipase, esterification, fungal resting cells, Rhizopus oryzae, palmitic acid, propanol. RESUMEN En el presente estudio, un modelo cinético para la síntesis de esteres usando Rhizopus oryzae resting cells es propuesto. El estudio cinético fue realizado en un rango de temperatura de 30-50 ºC a presión atmosférica reducida. La influencia de las variables de operación tales como temperatura, pH y contenido de agua fueron estudiadas. Diferentes valores de concentración de micelio y relación molar de ácido/alcohol son ensayadas, Las velocidades iníciales se estimaron de la curva de concentración de acido palmítico, y su correspondiente conversión a ester en menos del 10%, frente a tiempo y reportadas en mmol I-1 min -1. Los valores de las constantes cinéticas fueron calculados usando el programa freeware SIMFIT (http:\\\\www.simfit.man.ac.uk. Palabras clave: Lipasas, esterificación, resting cells, Rhizopus oryzae, acido palmítico, propanol.

  3. Evaluación de la educación nutricional y un suplemento para prevenir la anemia durante la gestación.

    Directory of Open Access Journals (Sweden)

    Beatriz Elena Parra

    2005-06-01

    Full Text Available Introducción. Las deficiencias de hierro y acido fólico son la causa de graves problemas de salud en la mujer gestante y en el niño, con implicaciones negativas para el desarrollo económico y social de los países. Objetivos. Evaluar los cambios de conocimientos sobre funciones, alimentos fuentes y biodisponibilidad del hierro y folatos, el consumo y la tolerancia de un suplemento y el comportamiento de los índices globulares en gestantes del programa prenatal de la Empresa Social del Estado Hospital Gilberto Mejía Mejía de Rionegro, Antioquia, Colombia, entre abril de 2002 y abril de 2003. Materiales y métodos. Estudio cuasi experimental en una muestra de 42 madres, seleccionada por conveniencia, con una confianza del 95%. La intervención fue un programa de educación nutricional y el suministro de un suplemento con 60 mg de hierro elemental, 400 J.g de acido fólico y 70 mg de vitamina C, elaborado para la investigación por el Laboratorio Profesional Farmacéutico, LAPROFF. El efecto de la intervención se midió en los cambios de conocimientos relacionados con las practicas que modifican la biodisponibilidad y el consumo de alimentos fuentes de estos nutrientes, en la tolerancia y la adherencia al suplemento y en la modificación de variables hematológicas: hemoglobina, hematocrito y ferritina. Resultados. Hubo cambios positivos de conocimientos sobre cómo mejorar las practicas alimentarias y la ingestión del suplemento; el 94,4% de las participantes no presentó anemia al finalizar la gestación. Conclusión. Estos resultados concuerdan con otros provenientes de poblaciones similares; se justifica implementar esta estrategia integrada en los programas de control prenatal de Colombia.

  4. Emissions monitoring in conveyed gas flow: (a) sulfur oxides and nitrogen oxides expressed respectively as SO{sub 2} and NO{sub 2}, (b) inorganic chlorine and fluorine compounds as gases and vapours expressed as HCl and HF; Rilevamento delle emissioni in flussi gassosi convogliati: (a) ossidid di zolfo e ossidi di azoto espressi rispettivamente come SO{sub 2} e NO{sub 2}, (b) composti inorganici del cloro e del fluoro sotto forma di gas e vapore espressi rispettivamente come HCl e HF

    Energy Technology Data Exchange (ETDEWEB)

    Ziemacki, G.; Viviano, G. [ed.] [Isituto Superiore di Sanita`, Rome (Italy). Gruppo di lavoro `Modifiche per il rilevamento delle emissioni in atmosfera da impianti industriali`

    1998-03-01

    The method (a) enables the determination of sulfur oxides (SO{sub 2}) and nitrogen oxides (NO{sub 2}) in conveyed atmospheric emissions. A stream of flue gas is a sampled by a heated with a filter housing and absorbed by an alkaline solution of potassium permanganate. The absorption solution is analyzed by ion-exchange chromatography for the determination of sulfate ion and nitrate ion as SO{sub 2} and NO{sub 2}. The method (b) enables the determination of hydrochloric acid (HCl) and hydrofluoric acid (HF) in conveyed atmospheric emissions. A stream of flue gas is sampled by a heated probe with a filter housing and absorbed by an alkaline solution (NaOH). The absorption solution is analyzed by ion-exchange chromatography for the determination of chloride ion and fluoride ion as HCl and HF. [Italiano] Il metodo a) consente la determinazione, in emissioni atmosferiche convogliate, degli ossidi di zolfo (SO{sub 2}) e degli ossidi di azoto (NO{sub 2}). Il campionamento viene effettuato mediante sonda riscaldata, munita di sistema filtrante, e sistema di assorbimento in soluzione alcalina di permanganato di potassio. La soluzione di assorbimento viene analizzata mediante cromatografia a scambio ionico, determinando le concentrazioni di ioni solfato e nitrato come SO{sub 2} ed NO{sub 2}. Il metodo b) consente la determinazione, in emissioni atmosferiche convogliate, dell`acido cloridrico (HCl) e dell`acido fluoridrico (HF). Il campionamento viene effettuato mediante sonda riscaldata, munita di sistema filtrante, e sistema di assorbimento in soluzione alcalina (NaOH). La soluzione alcalina viene quindi analizzata mediante cromatografia a scambio ionico, deter,mminando le concentrazioni di ioni cloro e fluoro come HCl e HF.

  5. Comparing the Spectroscopic and Molecular Characteristics of Different Dissolved Organic Matter Fractions Isolated by Hydrophobic and Anionic Exchange Resins Using Fluorescence Spectroscopy and FT-ICR-MS

    Directory of Open Access Journals (Sweden)

    Morgane Derrien

    2017-07-01

    Full Text Available Despite the environmental significance of dissolved organic matter (DOM, characterizing DOM is still challenging due to its structural complexity and heterogeneity. In this study, three different chemical fractions, including hydrophobic acid (HPOA, transphilic acid (TPIA, and hydrophilic neutral and base (HPIN/B fractions, were separated from bulk aquatic DOM samples, and their spectral features and the chemical composition at the molecular level were compared using both fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS. The HPIN/B fraction was distinguished from the two acidic fractions (i.e., HPOA and TPIA by the EEM-PARAFAC, while the TPIA fraction was discriminated by using the molecular parameters derived from the FT-ICR MS analyses. Statistical comparison suggests that the spectral dissimilarity among the three chemical fractions might result from the acido-basic properties of DOM samples, while the differences in molecular composition were more likely to be affected by the hydrophobicity of the DOM fractions. The non-metric multidimensional scaling map further revealed that the HPOA was the most heterogeneous among the three fractions. The number of overlapping formulas among the three chemical fractions constituted only <5% of all identified formulas, and those between two different fractions ranged from 2.0% to 24.1%, implying relatively homogeneous properties of the individual chemical fractions with respect to molecular composition. Although employing chemical fractionation achieved a lowering of the DOM heterogeneity, prevalent signatures of either acido-basic property or the hydrophobic nature of DOM on the characteristics of three chemical isolated fractions were not found for this study.

  6. Synthesis and evaluation of polystyrene membranes for use in fuel cells; Sintesis y evaluacion de membranas base poliestireno para uso en celdas a combustible

    Energy Technology Data Exchange (ETDEWEB)

    Benavides, R. [Centro de Investigacion en Quimica Aplicada (CIQA), Saltillo, Coahuila (Mexico)] e-mail: robertob@ciqa.mx; Paula, M.M.S.; Da Silva, L.; Fiori, M.; Coronetti, J.C.; Silvano, W.F. [Lasicom, Universidade do Extremos Sul Catarinense (UNESC), Criciuma, S.C. (Brasil); B.M. Huerta [Centro de Investigacion en Quimica Aplicada (CIQA), Saltillo, Coahuila (Mexico)

    2009-09-15

    Polymeric membranes were prepared using mass copolymerization of acrylic/styrene with weight proportions of 90/10, 92/8 and 94/6 %, while using the cross-linked divinylbenzene (DVB) monomer with weight proportions of 0.1 and 0.001 % to improve the mechanical properties. The copolymers obtained were sulfonates with sulfuric acid concentrated for 0, 30, 85 and 120 minutes to improve its ionic exchange capacity. The materials were characterized using infrared spectroscopy, thermal analysis (TGA and DSC), cross-linked level with% Gel and acidity using titration with sodium hydroxide. The IR spectrum of the membranes before sulfonating shows the existence of traditional polymer bands used with two signals from homopolymers that are lost and two new signals appearing, corroborating the copolymerization reactions. The thermogravimetry shows a higher decomposition temperature for the cross-linked DVB membranes, while the DSC is not very useful for observing transitions due to the hygroscopicity of the membranes. Finally, the percentage of gel is related to the amount of DVB used and the acidity of the membranes increases with increasing amounts of acrylic acid, sulfonation time and DVB percentage, although this value depends a good deal on the ease of solubilizing the material. The ionic properties of the membranes with better mechanical properties were evaluated with a fuel cell prototype. [Spanish] Se prepararon membranas polimericas mediante la copolimerizacion en masa del estireno/acido acrilico en proporciones de 90/10, 92/8 y 94/6 % en peso, al mismo tiempo que se utilizo el monomero entrecruzante divinilbenceno (DVB) en proporciones de 0.1 y 0.001 % en peso, para mejorar sus propiedades mecanicas. Los copolimeros obtenidos fueron sulfonados con acido sulfurico concentrado durante periodos de tiempo de 0, 30, 85 y 120 minutos para mejorar su capacidad de intercambio ionico. Se caracterizaron los materiales mediante espectroscopia infraroja, analisis termicos (TGA y

  7. Energy alternative for the use of organic waste (swine feces) in the state of Tabasco; Alternativa energetica para el aprovechamiento de los desechos organicos (excretas de ganado porcino) en el estado de Tabasco

    Energy Technology Data Exchange (ETDEWEB)

    Ramon Garcia, E.; Angles Falconi, S.I.; Vazquez Magana, L.R.; Tun Perez, A.C. [Instituto Tecnologico de Villahermosa, Villahermosa, Tabasco (Mexico)]. Email: bioleliza_ramgar@hotmail.com; sergio_falcorp@hotmail.com

    2009-09-15

    Biogas is obtained from decomposing organic material due to the action of four types of bacteria, in the absence of oxygen: hydrolytic, producers of moncarbonate compounds and acidogenics, producing organic fatty acids and other polycarbonate compounds; acetogenic, producers of hydrogen and CO{sub 2}; homoacetogenic, that can convert a considerable amount of multicarbonate or monocarbonate compounds into acetic acid and; metanogenic, producers of methane gas, the principal component of biogas. To design and build the pilot equipment proposed for this research, a 20-liter container was used with 10 kg of swine feces with identical volumes of inoculates. The aerobic fermentation process was immediate begun, followed by the anaerobic process; metabolic reactions were conducted. A total of 0.119 m3 of biogas was obtained from the anaerobic fermentation of 10 kg of swine feces, 60% (0.0714 m{sup 3}) of which was methane gas and the remaining 40%(0.0476 m{sup 3}) hydrogen sulfide (HS). During this investigation, it was concluded that obtaining this by-product (methane biogas), which can be used as a biofuel, provides an economically and ecologically sustainable alternative that reduces organic discharges (swine feces) into rivers and reduces the energy expenditures of swine farms. Because of the high generation of RSM, the creation of a biogas production plant in Tabasco is proposed. [Spanish] El biogas se obtiene al descomponerse la materia organica debido a la accion de cuatro tipos de bacterias, en ausencia de oxigeno: las hidroliticas, que producen compuestos monocarbonados, las acidogenicas producen acidos grasos organicos y otros compuestos policarbonados; las acetogenicas productoras de Hidrogeno y CO{sub 2}; las homoacetogenicas, que pueden convertir una cantidad considerable de compuestos multicarbonados o monocarbonados en acido acetico; y las metanogenicas, productoras del gas metano, principal componente del biogas. Para el diseno y construccion del equipo

  8. Caracterización y estudio de la fermentación espontánea del suero costeño producido en Montería

    Directory of Open Access Journals (Sweden)

    Mónica Simanca S

    2010-04-01

    Full Text Available Objetivo. Caracterizar el proceso fermentativo del suero costeño elaborado en Montería. Materiales y métodos. Se caracterizó fisicoquímica y bromatológicamente el producto elaborado artesanalmente en Montería; se evaluó durante 24 horas la fermentación espontánea del producto elaborado en las microempresas, se determinó pH, acidez total, concentración de lactosa y mesófilos aerobios cada tres horas. Se aislaron y seleccionaron los microorganismos involucrados en la fermentación, teniendo en cuenta las propiedades de interés tecnológico y se identificaron bioquímicamente por API 50CH (BioMérieux. Resultados. El suero costeño de contenido medio en grasa, presentó una humedad de 76%, extracto etéreo (11.65%, proteína (5.09%, lactosa (4.36%, cenizas (2.88%, cloruros (2.34%, pH (3.94 y acidez (1.4% acido láctico. En la fermentación espontánea se observó un comportamiento inversamente relacionado entre el pH y la acidez, alcanzando al final del estudio un valor de 4.69 y 0.67% de ácido láctico respectivamente; se encontró un porcentaje de lactosa de 4.44% y una población de mesófilos aerobios de 2x109 UFC/mL. Se aislaron tres cepas de bacterias acido lácticas (BAL identificadas como Enterococcus faecium y Lactobacillus brevis. Conclusiones. Las características fisicoquímicas y bromatológicas del suero costeño elaborado en la ciudad de Montería, no presentaron diferencias estadísticamente significativas entre los productos. En la fermentación espontanea hubo consumo de lactosa, aumento de la concentración de mesófilos aerobios y se presentó una relación inversa entre pH y acidez. Se aislaron e identificaron BAL con la posibilidad de ser utilizadas como cultivos iniciadores.

  9. Correlacion entre metodos de analisis de Zn disponible en cuatro ordenes de suelos de Costa Rica

    Directory of Open Access Journals (Sweden)

    Eloy Molina

    2001-01-01

    Full Text Available Se realizo una comparación entre métodos analisis del Zn disponible en 4 ordenes de sue- Analytilos de Costa Rica (Ultisoles, Vertisoles, Andisoles Inceptisoles, 25 de c/u, utilizando las siguientes soluciones extractoras: Olsen Modificado, Meh- lich 3, Morgan Modificado, DTPA y HC1. Las cantidades de Zn extrafdas dependieron de la natu- raleza qufmica de la solucion extractora. El HCl presento los contenidos mas altos de Zn en los chasuelos, excepto en Vertisoles. Las soluciones que hicontienen el agente quelante EDTA (Olsen Modi- ficado y Mehlich`3, extrajeron niveles interme- Modidios de Zn, en tanto que los metodos que contie- Den el quelato DTPA (Morgan Modificado y DT - PA, obtuvieron los valores mas bajos. Las corre- laciones de Zn extrafble entre los 5 metodos fue- signifirOD significativas en la mayona de los casos, tanto nivel de orden de suelos como en el conjunto de indivilos 100 suelos analizados. Los coeficientes de co- rrelacion mas altos, se presentaron entre Mehlich Morgan Modificado y DTPA. Las correlaciones Modifueron consistentes en los 4 ordenes, 10 que indica que estas soluciones poseen un amplio margen de adaptacion a diferentes tipos de suelo, siendo una caractenstica ventajosa para la selección de un metodo de analisis. El Olsen Modificado fue mas slighteficiente para la extraccion de Zn en suelos de pH ligeramente acido 0 neutro (Vertisoles e Inceptiso- les, que en suelos acidos (Ultisoles y Andisoles. EI HCI extrajo cantidades muy aItas de Zn que Moraparentementestan relacionadas con formas no disponibles para lag plantas. Se concluye que lag soluciones Mehlich 3, Morgan Modificado y DT - PA son semejantes en la forma de extraer Zn dispo- Dible, y podrian seT una altemativa para sustituir el metoda tradicional de Olsen Modificado utilizado en Costa Rica. Sin embargo,la eficiencia de ellas no puede seT establecida sino a traves de log estudios de correlacion contra rendimiento en invernadero y campo.

  10. Adaptations respiratoires et circulatoires de l'esturgeon sibérien à une hypoxie environnementale

    Directory of Open Access Journals (Sweden)

    MAXIME V.

    1998-07-01

    Full Text Available Les adaptations respiratoires, acido-basiques et quelques effets circulatoires ont été étudiés chez l'esturgeon sibérien Acipenser baeri lors d'une hypoxie progressive ou d'un choc hypoxique, et du retour en normoxie. Au cours d'une hypoxie progressive, ce poisson est capable, en hyperventilant, de maintenir constante sa consommation d'oxygène jusqu'à une valeur critique de pression partielle d'oxygène dans l'eau située entre 20 et 40 mmHg. Le retour en normoxie est caractérisé par le paiement d'une dette d'oxygène, indiquant qu'un recours au métabolisme anaérobie a été nécessaire durant l'hypoxie. L'hypoxie progressive provoque initialement une alcalose ventilatoire associée ensuite à une acidose métabolique. Le choc hypoxique induit un état de stress comme en témoignent les valeurs élevées des taux plasmatiques de catécholamines. L'hyperventilation initiale est suivie d'une importante dépression ventilatoire. L'hypertension observée dans un premier temps, bien que modérée, représente un effet d'une augmentation du taux de catécholamines plasmatiques. Cet effet est ensuite atténué par une bradycardie d'origine vraisemblablement vagale, concomitante de l'hypoventilation. Les conséquences sur l'équilibre acido-basique, bien qu'amplifiées, sont comparables à celles d'une hypoxie progressive. Cependant, la libération très importante de lactate dans le sang lors du retour en normoxie n'entraîne qu'une faible diminution de pH du fait d'une augmentation concomitante du taux de sodium plasmatique. Ainsi l'esturgeon Acipenser baeri, bien que considéré comme un poisson archaïque, a développé les mêmes réponses adaptatives à l'hypoxie que les téléostéens.

  11. Efecto sobre la viabilidad celular de una nueva serie de espirosteroides sintéticos en células PC12 Effect of a new series of synthetic spiroteroids on the PC12 cell line viability

    Directory of Open Access Journals (Sweden)

    Laura García-Pupo

    2013-03-01

    Full Text Available Introducción: la diosgenina y sus derivados se han descrito como potentes inhibidores de la proliferación en varias líneas tumorales. Sin embargo otras moléculas relacionadas estructuralmente con dichos derivados, se han reportado como candidatos terapéuticos y otras de ellas se incluyen en alimentos de consumo humano. Objetivo: el presente trabajo evalúa el efecto sobre la viabilidad celular de una nueva serie de espiroesteroides sintéticos derivados de la diosgenina, en células tipo neurales PC12. Métodos: la viabilidad de los cultivos de PC12 se determinó mediante el ensayo de MTT y se calcularon descriptores moleculares teóricos como la lipofilicidad (logP virtual y la superficie de área polar (SAP, con el objetivo de establecer relaciones estructura-actividad. Resultados: nuestros resultados demuestran que solo el acido taurodesoxicólico disminuye de manera significativa la viabilidad celular. Más aun, dicha molécula presenta valores menores y mayores de logP virtual y SAP, respectivamente, respecto al resto de los esteroides de la serie. Conclusiones: los resultados anteriores avalan el estudio del acido taurodesoxicólico como potencial inhibidor de la proliferación celular y al resto de las moléculas de la serie como candidatos neuroprotectores a evaluar en esta misma línea celular y dosis de tratamiento.Introduction: diosgenin and its derivatives have been described as potent anti-proliferative compounds in several tumor cell lines. However, other structurally-related compounds are reported to exert neuroprotective activity and are also included in food for human consumption. Objective: to evaluate the effect of a novel series of diogesin-derived synthetic spirosteroids on cellular viability of neuron-like PC12 cell line. Methods: cellular viability was determined by the MTT assay along with some theorical molecular descriptors, such as lipophilicity and polar surface area, in order to establish the structure

  12. Vitamina C, carotenoides, fenólicos totais e atividade antioxidante de goiaba, manga e mamão procedentes da Ceasa do Estado de Minas Gerais = Vitamin C, carotenoids, phenolic compounds and antioxidant activity of guava, mango and papaya from Ceasa of Minas Gerais State

    Directory of Open Access Journals (Sweden)

    Daniela da Silva Oliveira

    2011-01-01

    Full Text Available Este estudo teve como objetivo analisar o conteudo de compostos antioxidantes (acido ascorbico - AA, acido desidroascorbico - ADA, vitamina C total, licopeno, £]-caroteno, £]-criptoxantina e estimativa de compostos fenolicos e avaliar a atividade antioxidante, em goiaba, manga e mamao. A analise de carotenoides e vitamina C foi realizada por Cromatografia Liquida de Alta Eficiencia (CLAE. O teor de fenolicos totais foi determinado utilizando o reagente de Folin-Ciocalteu e leitura espectrofotometrica. A atividade antioxidante foi avaliada pelo Teste do 2,2-diphenil-2-picril-hidrazil (DPPH¡E e do Poder Redutor. A Anova (ƒÑ = 0,05 foi utilizada para a analise dos dados. Os teores dos constituintes antioxidantes diferiram entre as tres frutas, mas a goiaba foi a fruta que apresentou teores mais elevados de compostos fenolicos, vitamina C total, ADA e licopeno, alem dos maiores valores para atividade antioxidante. Foi constatada forte correlacao entre os testes que avaliaram a atividade antioxidante e o teor de fenolicos totais, demonstrando serem estes os principais compostos antioxidantes a contribuirem para a atividade antioxidante das frutas analisadas, em ambos os testes. E importante incentivar a utilizacao das frutas avaliadas neste estudo, tanto em nivel domestico quanto em estabelecimentos de alimentacao coletiva para aumentar o consumo de antioxidantes naturais pela populacao.This study aimed to analyze the content of antioxidant compounds (ascorbic acid - AA, dehydroascorbic acid - DHA, total vitamin C, lycopene, £]-carotene, £]-cryptoxanthin and phenolic compounds and to evaluate the antioxidant activity in guava, mango and papaya.The analysis of carotenoids and vitamin C was performed by high performance liquid chromatography (HPLC. The content of phenolic compounds was determined using the Folin-Ciocalteu reagent and spectrophotometric reading. Antioxidant activity was evaluated by testing the 2.2-diphenyl-2-picryl

  13. Adsorption mechanism of acids and bases in reversed-phase liquid chromatography in weak buffered mobile phases designed for liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2009-03-06

    The overloaded band profiles of five acido-basic compounds were measured, using weakly buffered mobile phases. Low buffer concentrations were selected to provide a better understanding of the band profiles recorded in LC/MS analyses, which are often carried out at low buffer concentrations. In this work, 10 microL samples of a 50 mM probe solution were injected into C(18)-bonded columns using a series of five buffered mobile phases at (SW)pH between 2 and 12. The retention times and the shapes of the bands were analyzed based on thermodynamic arguments. A new adsorption model that takes into account the simultaneous adsorption of the acidic and the basic species onto the endcapped adsorbent, predicts accurately the complex experimental profiles recorded. The adsorption mechanism of acido-basic compounds onto RPLC phases seems to be consistent with the following microscopic model. No matter whether the acid or the base is the neutral or the basic species, the neutral species adsorbs onto a large number of weak adsorption sites (their saturation capacity is several tens g/L and their equilibrium constant of the order of 0.1 L/g). In contrast, the ionic species adsorbs strongly onto fewer active sites (their saturation capacity is about 1g/L and their equilibrium constant of the order of a few L/g). From a microscopic point of view and in agreement with the adsorption isotherm of the compound measured by frontal analysis (FA) and with the results of Monte-Carlo calculations performed by Schure et al., the first type of adsorption sites are most likely located in between C(18)-bonded chains and the second type of adsorption sites are located deeper in contact with the silica surface. The injected concentration (50 mM) was too low to probe the weakest adsorption sites (saturation capacity of a few hundreds g/L with an equilibrium constant of one hundredth of L/g) that are located at the very interface between the C(18)-bonded layer and the bulk phase.

  14. Comparison of energy expenditure and closed-loop performance of thermal and reactive distillation sequences coupled for biodiesel production; Comparacion de gasto energetico y desempeno a lazo cerrado de secuencias de destilacion reactiva y termicamente acopladas para produccion de biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Cornejo-Jacob, J.L [Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan (Mexico); Vazquez-Ojeda, M; Segovia-Hernandez, J.G; Hernandez, S [Universidad de Guanajuato, Guanajuato, Guanajuato (Mexico); Maya-Yescas, R. [Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan (Mexico)]. E-mail: rmayay@umich.mx

    2013-03-15

    Biodiesel is the common name for fatty acid methyl esters, obtained by esterification (basic catalysis) or trans-esterification (acid catalysis) of vegetable or animal oils with alcohols, and used as liquid fuel. Production involves the reaction, under mild conditions, between the oil and, typically, excess of methanol. Traditional production of biodiesel exhibits some handicaps, such as the shift of equilibrium to fatty acids by using excess of alcohol that must be separated and recycled. As alternative, it is possible to integrate reaction/separation operations into a single intensified unit, a reactive distillation column, followed by a second separation unit. These configurations exhibit several advantages such as shifting equilibrium in the reactive region and, because of the thermal integration with the second unit, energy savings during products separation. In order to design these production sequences taking advantage of steady state knowledge (energy savings) and considering dynamic performance, this work performs a controllability analysis for six possible configurations; open-loop control properties, evaluated by single value decomposition, are probed by implementing PI controllers to the system. The reactive distillation column coupled to a stripper, without reboilers, shows to be the best option in terms of closed-loop performance and energy savings. [Spanish] Biodiesel es el nombre comun dado a metil esteres de acidos grasos obtenidos por esterificacion (catalisis basica) o trans-esterificacion (catalisis acida) de aceites animales o vegetales con alcoholes, y usados como combustibles liquidos. Su produccion involucra la reaccion entre el aceite y, tipicamente, exceso de metanol a condiciones moderadas. La produccion tradicional de biodiesel exhibe algunas desventajas como el desplazamiento del equilibrio hacia acidos grasos debido al exceso de alcohol, que debe ser separado y reciclado. Alternativamente, es posible integrar las operaciones reaccion

  15. Synthesis and electrochemical characterization of highly tolerant Pd electrocatalysts as cathodes in direct ethylene glycol fuel cells (DEGFC)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Varela, F.J.; Fraire Luna, S. [Cinvestav, Unidad Saltillo, Ramos Arizpe, Coahuila (Mexico)] e-mail: javier.varela@cinvestav.edu.mx; Savadogo, O. [Laboratoire d' Electrochimie et de Materiaux Energetiques, Ecole Polytechnique de Montreal, Montreal, QC (Canada)

    2009-09-15

    Highly selective Pd electrocatalysts were synthesized by the formic acid method and evaluated as cathodes for DEGFC applications. In rotating disc measurements in acid medium, the Pd/C cathode showed important catalytic activity for the Oxygen Reduction Reaction (ORR). In the presence of ethylene glycol (EG, C{sub 2}H{sub 6}O{sub 2}), Pd/C exhibited an excellent electrochemical behavior and full tolerance to the organic molecule. No current density peaks associated to the EG oxidation reaction emerged and the shift in onset potential for the ORR (Eonset) toward more negative potentials was negligible on this cathode. Moreover, the evaluation of Pd/C in a DEGFC operating at 80 degrees Celsius demonstrated its high performance as cathode. As a comparison, commercial Pt/C was tested under the same conditions showing a limited selectivity for the ORR. The detrimental effect of EG on the Pt electrocatalysts resulted in high intensity current density peaks due to the oxidation of EG and a significant shift in Eonset. Given these results, it is expected that highly efficient Pd-based cathodes can find application in DEGFCs. [Spanish] Se sintetizaron electrocatalizadores altamente selectivos mediante el metodo de acido formico y se evaluaron como catodos en aplicaciones de CCGED. En mediciones de disco rotatorio en medio acido, el catodo Pd/C mostro importante actividad catalitica en la reaccion de reduccion de oxigeno (RRO). En la presencia de glicol de etileno (GE, C{sub 2}H{sub 6}O{sub 2}), Pd/C exhibio un excelente comportamiento electromecanico y tolerancia total a la molecula organica. No surgieron picos de densidad de corriente asociados con la reaccion de oxidacion de GE y el corrimiento en el potencial de inicio para la RRO (Einicio) hacia potenciales mas negativos fue despreciable en este catodo. Como comparacion, se probo un Pt/C bajo las mismas condiciones y se observo una selectividad limitada para el RRO. El efecto perjudicial de GE en el electrocatalizador

  16. Lewis acid catalyzed transformations of Z-ligustilide

    Energy Technology Data Exchange (ETDEWEB)

    Rios, Maria Yolanda [Universidad Autonoma del Estado de Morelos, Cuernavaca, Morelos (Mexico); Delgado, Guillermo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    1999-08-01

    Some Lewis acid mediated reactions of Z-ligustilide (1), a bioactive constituent of the medicinal species Ligusticum porteri, were investigated. These reactions provided varying mixtures of Z-butylidenephthalide (7), E-butylidenephthalide (8), n-butyphthalide (13), and novel linear dimeric phthalides (9-12) as the main products. The formation of the dimers occurred in low yields and with regio and situ-selectivity. Initial competitive O- and C- complexation of the Lewis acid with Z-ligustilide promoted the formation of the dimers occurred in low yields and with regio and situ- selectivity. Initial competitive O- and C- complexation of the Lewis acid with Z-ligustilide promoted the formation of carbocations at C(8), C(6) and C(7), which were stabilized by the addition of the C(6')-C(7') olefin of a second unit of the starting material, to provide cations at C(6') and C(7'). Subsequent isomerizations and elimination of the catalyst afforded the dimeric products 9-12. The yields and structure of the products are quite dependent on variations of the reaction conditions and the catalyst employed. [Spanish] Se investigaron algunas reacciones de Z-ligustilidas (1), un constituyente bioactivo de la planta medicinal Ligusticum porteri, catalizadas por acidos de Lewis. Estas reacciones produjeron mezclas variables de Z-butilidenftalida (7), E-butilidenftalida (8), n-butilftalida (13), y ftalidos dimetricos lineales novedosos (9-12) como productos principales. La formacion de los dimeros procedio en rendimientos bajos y con regio- y situ-selectividad. La O- y C- complejacion competitiva inicial del acido de Lewis con Z-lingustilida promueve la formacion de cationes en C(8), C(6) y C(7), los cuales son estabilizados por la adicion de la olefina C(6')-C(7') de una segunda unidad de la materia prima para generar los cationes en C(6')-C(7'). Isomerizaciones subsecuentes y la eliminacion del catalizador conducen a los productos dimericos 9

  17. CARACTERIZACIÓN DE POLVOS DE ACERÍA ELÉCTRICA PRODUCIDOS EN VENEZUELA Y EVALUACIÓN PRELIMINAR DE SU LIXIVIABILIDAD CON ÁCIDOS ORGÁNICOS DILUIDOS

    Directory of Open Access Journals (Sweden)

    PEDRO DELVASTO

    2011-01-01

    Full Text Available Se estudiaron polvos de aceria cuyo analisis quimico revelo un contenido (en peso de: 27,0 % de Fe; 7,1 % de Mg; 4,9 % de Zn; 4,0 % de Ca y 0,5 % de Pb. La difraccion de rayos X y la espectroscopia infrarroja, permitio identificar en los polvos las siguientes fases: espinelas, Fe3O4, CaCO3, SiO2, ZnO y PbO. El analisis microscopico de estos residuos indico que estan formados por agregados de particulas esferoidales cuyo tamano varia entre 120 y 0,25 ¿Êm. La lixiviabilidad de los mismos se evaluo durante 28 dias en columnas de percolacion, empleando agua y disoluciones de acidos organicos como agentes lixiviantes. El objetivo fue evaluar el comportamiento del residuo bajo condiciones similares a las que generan los microorganismos naturales del suelo. Se encontro que la lixiviabilidad de Zn y Pb vario entre 80 y 16 mg mensuales por kilogramo de polvo de aceria.

  18. Static leaching of Spanish uranium ores; Lixiviacion estatica de minerales espanoles de uranio

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, G; Gasos, P; Merino, J L; Suarez, Y E [Direccion de Plantas Piloto e Industriales, Junta de Energia Nuclear, Madrid (Spain)

    1967-06-15

    The paper summarizes the experience acquired in Spain during seven years of investigation on the static leaching of uranium ores. The operations covered minerals showing wide variations with regard to both uranium content (250 and 2000 ppm) and the type of rock and gangue (granites, shales, sandstones, sulphides, carbonates, limonites etc.). The studies were carried out on quantities of material varying from a few kilograms to several tons. Leaching agents included water, solid reagents (pyrites), alkaline carbonates and sulphuric acid. The systems used consisted of both simple layouts and other, more elaborate schemes including recycling of the liquors. The uranium was recovered from the liquors first by direct precipitation and later by ion-exchange and extraction with amines. (author) [Spanish] La memoria resume la experiercia espanola de siete anos de estudio sobre lixiviacion estatica de minerales de uranio. Se ha estudiado una gran variedad de minerales tanto en lo que respecta a ley de uranio (250 y 2000 ppm), como a la naturaleza de las rocas y gangas (granitos, pizarras, areniscas, sulfuros, carbonatos, limonitas, etc.). Los estudios se han realizado en diferentes escalas, desde kilogramos a varias toneladas. Los agentes de lixiviacion han sido variables: agua, reactivos solidos (piritas), carbonatos alcalinos y acido sulfurico. Los circuitos empleados se refieren tanto a esquemas sencillos, como a otros mas elaborados con recirculaciones de liquido. La recuperacion del uranio de los liquidos se resolvio inicialmente por precipitacion directa, pero luego se efectuo mediante cambio de ion y extraccion con aminas. (author)

  19. Spanish radioactive lignites, nature and solubility of the uranium; Lignitos radiactivos espanoles, naturaleza y solubilizacion del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Josa, J M; Merino, J L; Villoria, A [Direccion de Plantas Piloto e Industriales, Junta de Energia Nuclear, Madrid (Spain)

    1967-06-15

    The authors describe the features of some 70 samples of radioactive lignites from various places in Spain (Huesca, Lerida, Teruel, Galicia and Murcia) with uranium contents varying between 20 and 1200 ppm. They carried out experiments on extraction of the uranium from these ores both by direct treatment and after roasting to eliminate organic matter and bring about concentration. The acid method was considered for leaching of the uranium from the substances in question using agitation and static bed techniques. Investigations were also carried out on the effect of the variables represented by grain size, amount of acid, temperature time and oxidants, in addition to those involved in the roasting process. (author) [Spanish] Los autores presentan las caracteristicas de unas 70 muestras de lignitos radiactivos procedentes de distintos puntos de Espana (Huesca, Lerida, Teruel, Galicia y Murcia) con leyes de uranio comprendidas entre 20 y 1200 ppm. El beneficio del uranio de estos minerales se ha abordado por tratamiento directo y despues de someterlos a tostacion, lo que elimino la materia organica y produjo enriquecimiento. La lixiviacion del uranio de los productos indicados se considero por via acida, utilizando tecnicas de agitacion y de lecho estatico. Se investigo la influencia de las variables tamano de grano, dosis de acido, temperatura, tiempo y oxidante, ademas de las implicadas en los procesos de tostacion. (author)

  20. Contributions to the chemistry of highly concentrated electrolyte solutions. XXXIX. Investigation of Be/sup 2 +/ complex formation by the method of molar volumes

    Energy Technology Data Exchange (ETDEWEB)

    Jedinakova, V [Vysoka Skola Chemicko-Technologicka, Prague (Czechoslovakia). Katedra Technologie Jadernych Paliv a Radiochemie

    1974-01-01

    The formation of aquo- and acido-complexes of the Be/sup 2 +/ ion in aqueous solutions of strong electrolytes was studied by densimetry. In all the systems studied, HClO/sub 4/, HNO/sub 3/, NaNO/sub 3/, KOH, Ca(ClO/sub 4/)/sub 2/, CaCl/sub 2/, the overall coordination number 4 was confirmed for the complex forms of the Be/sup 2 +/ ion. If BeSO/sub 4/ is used as the differential addition in a solvent not forming complexes, dissociation of the sulfate proceeds under the formation of the aquo-complex (Be(H/sub 2/O)/sub 4/)/sup 2 +/. If beryllium perchlorate is used, the Be/sup 2 +/ ion remains in that form, in which it is added to the solution (i.e. the complex form (Be(H/sub 2/O)/sub 2/(ClO/sub 4/)/sub 2/)), in the whole concentration range of the applied isomolar series Ca(ClO/sub 4/)/sub 2/-CaCl/sub 2/, NaClO/sub 4/-NaBr, and NaClO/sub 4/-NaI.

  1. CO{sub 2} sequestration technologies

    Energy Technology Data Exchange (ETDEWEB)

    Ketzer, Marcelo [Brazilian Carbon Storage Research Center (Brazil)

    2008-07-15

    In this presentation the importance of the capture and sequestration of CO{sub 2} is outlined for the reduction of gas discharges of greenhouse effect; then the principles of CO{sub 2} storage in geologic formations are reviewed; afterwards, the analogs for the CO{sub 2} storage are commented, such as the storage of the acid gas, the natural gas storage and the natural CO{sub 2} deposits. Also it is spoken on the CO{sub 2} storage in coal, in water-bearing saline deposits and in oil fields, and finally the subject of the safety and monitoring of the CO{sub 2} storage is reviewed. [Spanish] En esta presentacion se expone la importancia de la captura y secuestro de CO{sub 2} para la reduccion de emisiones de gases de efecto invernadero; luego se tratan los principios de almacenamiento de CO{sub 2} en formaciones geologicas; despues se comentan los analogos para el almacenamiento de CO{sub 2} como el almacenamiento del gas acido, el almacenamiento de gas natural y los yacimientos naturales de CO{sub 2}. Tambien se habla sobre el almacenamiento de CO{sub 2} en carbon, acuiferos salinos y yacimientos petroliferos y por ultimo se toca el tema de la seguridad y monitoreo del almacenamiento de CO{sub 2}.

  2. Lignin recovery. A resource to value; La lignina: una risorsa da valorizzare

    Energy Technology Data Exchange (ETDEWEB)

    Zimbardi, P.; Cardinale, G.; Demichele, M.; Nanna, F.; Viggiano, D. [ENEA, Centro Ricerche Trisaia, Rotondella, MT (Italy). Dipt. Energia; Bonini, C.; D' Alessio, L.; D' Auria, M.; Teghil, R.; Tofani, D. [Basilicata Univ., Potenza (Italy). Dipt. di Chimica

    1999-07-01

    In the present paper, the effects of the steam explosion (ES) pretreatment conditions on recovery and chemical structure of wheat straw lignin are reported. The experimental data of lignin recovery by caustic extraction, followed by acid precipitation, have been interpolated to obtain the dependence on the time and temperature of SE. The lignin has been characterised by using several methods. Preliminary results on the synthesis of copolymers lignin-styrene are also reported. [Italian] Si ripotano i risultati piu' rilevanti di un'attivita' di ricerca condotta dall'ENEA e dall'universita' della Basilicata, finalizzata alla valorizzazione della lignina. Sono stati indagati gli effetti del trattamento con vapore d'acqua ad alta pressione (processo steam explosion) sulla struttura chimica della lignina e la possibilita' di isolarla con alte rese di estrazione dalla paglia di grano. La lignina, estratta dalla biomassa trattata con una soluzione acquosa di idrossido di sodio ed isolata acidificando la soluzione con acido solforico, e' stata analizzata con diverse tecniche microscopiche, spettroscopiche e cromatografiche. Sono riportati i dati sperimentali interpolati ottenendo la relazione empirica che lega la resa di recupero alla temperatura e alla durata del trattamento di steam explosion.

  3. Analytic techniques to quantify Tetrachlorohydroquinone and Chloranil; Tecnicas analiticas para cuantificar Tetraclorohidroquinona y Cloranilo

    Energy Technology Data Exchange (ETDEWEB)

    Castillo Escobedo, Ma. Teresa; Gutierrez de Gonzalez, Luz Ma; Gojon Zorrilla, Gabriel [Universidad Autonoma de Nuevo Leon, Monterrey, Nuevo Leon (Mexico)

    1995-02-01

    Tetrachlorohydroquinone (TCHQ) was determined by two methods: iodometry and cerimetry. Tritation with aqueous ceric ammonium sulphate using potentiometric end-point detection proved to be the method of choice on account of its coefficient of variation (CV=0.475%) and its excellent accuracy. Chloranil (TCQ) was quantified by titration with aqueous ascorbic acid in acetone-water-hexamethylene tetramine (HMT), the golden-yellow color of the TCQ-HMT complex disappearing at the end point. This method is accurate and has CV=0.396%. [Spanish] Se cuantifico la tetraclorohidroquinona (TCHQ) mediante una tecnica yodometrica y un metodo potenciometrico, basado en el uso de sulfato cerico amoniacal. Se concluyo que el metodo potenciometrico es el mejor, ya que tiene un coeficiente de variacion (CV) de 0.475%, y una exactitud muy aceptable. Se desarrollo un tecnica para cuantificar el Cloranilo (TCQ) por titulacion con Acido Ascorbico en presencia de Hexametilentetramina (HMT) en medio acetona-agua; el punto final se determino por la separacion del color amarillo oro del complejo TCQ-HMT. Esta tecnica presenta un coeficiente de variacion (CV) de 0.396% y una exactitud aceptable. Se realizaron pruebas de hipotesis para verificar la exactitud de los metodos elegidos.

  4. Methane production from cellulosic wastes: kinetic studies

    Energy Technology Data Exchange (ETDEWEB)

    Goma, G; De La Torre, I; Maugheri, F; Yameogo, T

    1979-09-01

    The anaerobic fermentation is studied on lignocellulosic materials and sucrose as substrate. With the lignocellulosic material cellulolysis is rate limiting. The reducing sugar concentration in the fermentation broth is less than 15 mgl/sup -1/. With rumen bacteria, 50% of the initial polyoside are used and 12% of the lignin is solubilized. With sucrose studies on the kinetic behaviour of the mixed population responsible of the acidogenesis step permite to find the optimal temperature (40/sup 0/C) feed substrate concentration (50 gl/sup -1/) residence time (60 hours) and pH (5,5 - 6). The better technology is a plug flow fermentor with cell recycling. Modeling of the behaviour of this reactor was performed. The use of this reactor for the selection of acido resistant bacteria is discussed. For methanogenesis, in continuous culture, the ideal technology seems to be an association of two reactors. In the first step, a plug flow reactor must be used for acidogenesis, and in the second step a well mixed reactor permit the conversion of organic acids in methane.

  5. Pharmacomodulation of the Antimalarial Plasmodione: Synthesis of Biaryl- and N-Arylalkylamine Analogues, Antimalarial Activities and Physicochemical Properties

    Directory of Open Access Journals (Sweden)

    Karène Urgin

    2017-01-01

    Full Text Available With the aim of increasing the structural diversity on the early antimalarial drug plasmodione, an efficient and versatile procedure to prepare a series of biaryl- and N-arylalkylamines as plasmodione analogues is described. Using the naturally occurring and commercially available menadione as starting material, a 2-step sequence using a Kochi-Anderson reaction and subsequent Pd-catalyzed Suzuki-Miyaura coupling was developed to prepare three representative biphenyl derivatives in good yields for antimalarial evaluation. In addition, synthetic methodologies to afford 3-benzylmenadione derivatives bearing a terminal -N(Me2 or -N(Et2 in different positions (ortho, meta and para on the aryl ring of the benzylic chain of plasmodione were investigated through reductive amination was used as the optimal route to prepare these protonable N-arylalkylamine privileged scaffolds. The antimalarial activities were evaluated and discussed in light of their physicochemical properties. Among the newly synthesized compounds, the para-position of the substituent remains the most favourable position on the benzyl chain and the carbamate -NHBoc was found active both in vitro (42 nM versus 29 nM for plasmodione and in vivo in Plasmodium berghei-infected mice. The measured acido-basic features of these new molecules support the cytosol-food vacuole shuttling properties of non-protonable plasmodione derivatives essential for redox-cycling. These findings may be useful in antimalarial drug optimization.

  6. Fuel cells. Pt. 1; Celle a combustibile. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Campanari, S; Macchi, E [Milan Politecnico (Italy). Dip. di Energetica

    1999-01-01

    Direct conversion of chemical energy into electricity (without intermediate heat generation) is a long-established method to improve the efficiency of power generation, as well as to reduce polluting emissions from thermal plants. The origins of fuel cells, as well as their operating principles, are dealt with. Then, various types of cells are taken into consideration, on the basis of both their characteristics and the operating principles of electrolytes. Finally, structure and operation of Polymer Electrolyte Membrane Fuel Cells (PEMFC), Alkaline Fuel Cells (AFC) and Phosphoric Acid Fuel Cells (PAFC) are described. [Italiano] La conversione diretta dell`energia chimica del combustibile in energia elettrica, senza passare attraverso la produzione di calore, rappresenta una via ormai ampiamente collaudata per migliorare l`efficienza della produzione di energia elettrica e per contenere le emissioni generate dagli impianti termoelettrici. L`articolo, dopo una breve presentazione della storia dello sviluppo nel tempo delle celle a combustibile, espone i principi di funzionamento delle stesse. Si esaminano quindi i vari tipi di cella a partire dalle caratteristiche e dalle modalita` di funzionamento degli elettroliti che ne definiscono la classificazione. Successivamente vengono illustrate le caratteristiche costruttive e funzionali delle celle ad elettrolita polimerico (PEMFC), delle celle alcaline (AFC) e delle celle ad acido fosforico (PAFC).

  7. A prototype of volume-controlled tidal liquid ventilator using independent piston pumps.

    Science.gov (United States)

    Robert, Raymond; Micheau, Philippe; Cyr, Stéphane; Lesur, Olivier; Praud, Jean-Paul; Walti, Hervé

    2006-01-01

    Liquid ventilation using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation, such as decreased lung damage, recruitment of collapsed lung regions, and lavage of inflammatory debris. We present a total liquid ventilator designed to ventilate patients with completely filled lungs with a tidal volume of PFC liquid. The two independent piston pumps are volume controlled and pressure limited. Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume. Pump independence also allows easy functional residual capacity modifications during ventilation. The bubble gas exchanger is divided into two sections such that the PFC exiting the lungs is not in contact with the PFC entering the lungs. The heating system is incorporated into the metallic base of the gas exchanger, and a heat-sink-type condenser is placed on top of the exchanger to retrieve PFC vapors. The prototype was tested on 5 healthy term newborn lambs (<5 days old). The results demonstrate the efficiency and safety of the prototype in maintaining adequate gas exchange, normal acido-basis equilibrium, and cardiovascular stability during a short, 2-hour total liquid ventilator. Airway pressure, lung volume, and ventilation scheme were maintained in the targeted range.

  8. pH sensing by lipids in membranes: The fundamentals of pH-driven migration, polarization and deformations of lipid bilayer assemblies.

    Science.gov (United States)

    Angelova, Miglena I; Bitbol, Anne-Florence; Seigneuret, Michel; Staneva, Galya; Kodama, Atsuji; Sakuma, Yuka; Kawakatsu, Toshihiro; Imai, Masayuki; Puff, Nicolas

    2018-03-06

    Most biological molecules contain acido-basic groups that modulate their structure and interactions. A consequence is that pH gradients, local heterogeneities and dynamic variations are used by cells and organisms to drive or regulate specific biological functions including energetic metabolism, vesicular traffic, migration and spatial patterning of tissues in development. While the direct or regulatory role of pH in protein function is well documented, the role of hydrogen and hydroxyl ions in modulating the properties of lipid assemblies such as bilayer membranes is only beginning to be understood. Here, we review approaches using artificial lipid vesicles that have been instrumental in providing an understanding of the influence of pH gradients and local variations on membrane vectorial motional processes: migration, membrane curvature effects promoting global or local deformations, crowding generation by segregative polarization processes. In the case of pH induced local deformations, an extensive theoretical framework is given and an application to a specific biological issue, namely the structure and stability of mitochondrial cristae, is described. This article is part of a Special Issue entitled: Emergence of Complex Behavior in Biomembranes edited by Marjorie Longo. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Monocapas de ácidos grasos. I. Ácido esteárico sobre disoluciones acuosas de etanol

    Directory of Open Access Journals (Sweden)

    Rodríguez Patino, J. M.

    1991-04-01

    Full Text Available The structure and stability of fatty acid monolayers spread on aqueous solutions with ethanol has been studied. The experiments were carried out isothermically using a commercial Langmuir balance (Lauda. Monolayers exhibit solid or condensed liquid structure depending of the ethanol concentration in the subphase. Temperature has not a significant influence on the monolayer. Structure there is a loss of stearic acid film through solution into the adjacent subphase. This loss is increased with the temperature and ethanol concentration in the subphase.

    Monocapas de ácidos grasos. I. Acido esteárico sobre disoluciones acuosas de etanol. Se ha estudiado la estructura y estabilidad de monocapas de ácido esteárico esparcidas sobre disoluciones acuosas que contienen etanol. Las experiencias se han realizado en una balanza de superficie comercial tipo Langmuir y se ha operado en condiciones isotérmicas. Las monocapas presentan estructuras de tipo sólida o de líquido condensado en función de la concentración de etanol en la subfase. La estructura que adopta la monocapa es prácticamente independiente de la temperatura. La pérdida de moléculas de ácido esteárico de la monocapa por disolución en la subfase se incrementa a los valores más elevados de temperatura y de concentración de etanol.

  10. Ventana a la Farmacología

    Directory of Open Access Journals (Sweden)

    María Luisa Cárdenas Muñoz

    1996-04-01

    Full Text Available Terfenadina: no debe usarse con eritromicina: La terfenadina es un antihistamínico de segunda generación, cuyo uso se ha generalizado por producir menos sedación que los antihistamínicos de primera generación.  / Uso y abuso de corticoides tópicos oculares: A finales de la década de los cuarenta Kench y Kendall introdujeron la cortisona en la terapéutica humana, simultáneamente comenzó a ser utilizada con éxito en las inflamaciones oculares. /  Trastornos de pánico: pato fisiología y tratamiento: El tratamiento farmacológico del pánico se conoce y utiliza desde los años sesenta. Sinembargo, la comprensión del origen biológico de su pato fisiología sólo se comenzó a entender en años recientes. / Acido Acetil Salicilico y riesgo de Cancer Colorecal en mujeres: Evidencias muy importantes sugieren que el uso regular de ácido acetil salicílico (ASA y otros antiinflamatorios no esteroideos (AINE disminuye el riesgo de cáncer colorectal.

  11. Análisis del tratamiento ideal usando baños termotratados para la separación de cal de los residuos de descarne en curtiembres

    Directory of Open Access Journals (Sweden)

    Yelitza Aguas Mendoza

    2016-07-01

    Full Text Available Se analizó el tratamiento ideal usando baños termotratados para la separación de cal de los residuos de descarne, del proceso de curtición semiartesanal desarrollado en Sampués, Departamento de Sucre (Colombia. Para su desarrollo se seleccionó una muestra de carnaza representativa, homogénea y con menos tiempo de almacenamiento. Dicha muestra se redujo al tamaño de 1 cm2 y se conservó refrigerada para posteriormente realizar los análisis de grasa, pH y presencia de cal. Los baños termotratados de desencalado se realizaron a tres temperaturas diferentes (26, 30 y 35 ºC. Se utilizó como agente desencalante el acido sulfúrico en tres concentraciones (3, 2 y 1 N. Además se usó un sistema de agitación simulando el bombo en proceso industrial. Se llevaron a cabo nueve pruebas con tres repeticiones para mayor confiabilidad de los datos, en donde se determinó la correlación existente entre las variables independientes, temperatura y concentración, sobre la cal impregnada y los resultados de grasa en cada una de las muestras en un tiempo de 4 y 8 h.

  12. Pharmacomodulation of the Antimalarial Plasmodione: Synthesis of Biaryl- and N-Arylalkylamine Analogues, Antimalarial Activities and Physicochemical Properties.

    Science.gov (United States)

    Urgin, Karène; Jida, Mouhamad; Ehrhardt, Katharina; Müller, Tobias; Lanzer, Michael; Maes, Louis; Elhabiri, Mourad; Davioud-Charvet, Elisabeth

    2017-01-19

    With the aim of increasing the structural diversity on the early antimalarial drug plasmodione, an efficient and versatile procedure to prepare a series of biaryl- and N -arylalkylamines as plasmodione analogues is described. Using the naturally occurring and commercially available menadione as starting material, a 2-step sequence using a Kochi-Anderson reaction and subsequent Pd-catalyzed Suzuki-Miyaura coupling was developed to prepare three representative biphenyl derivatives in good yields for antimalarial evaluation. In addition, synthetic methodologies to afford 3-benzylmenadione derivatives bearing a terminal - N (Me)₂ or - N (Et)₂ in different positions ( ortho , meta and para) on the aryl ring of the benzylic chain of plasmodione were investigated through reductive amination was used as the optimal route to prepare these protonable N -arylalkylamine privileged scaffolds. The antimalarial activities were evaluated and discussed in light of their physicochemical properties. Among the newly synthesized compounds, the para -position of the substituent remains the most favourable position on the benzyl chain and the carbamate - N HBoc was found active both in vitro (42 nM versus 29 nM for plasmodione) and in vivo in Plasmodium berghei -infected mice. The measured acido-basic features of these new molecules support the cytosol-food vacuole shuttling properties of non-protonable plasmodione derivatives essential for redox-cycling. These findings may be useful in antimalarial drug optimization.

  13. Li tho bio chemistratrigraphy in Mina Verdum group Nico Perez terrain-Uruguay

    International Nuclear Information System (INIS)

    Gaucher, C.; Martinez, G.; Cernuschi, F.; Chiglino, L.; Sial, A.; Poire, D.

    2007-01-01

    The occurrence of volcanic and pyroclastic rocks in the Mina Verdun Group is reported here. The unit represents a marine volcanosedimentary succession, made up from base to top of the following formations: Cerro de las Viboras Formation (metarhyolites), Don Mario Formation (pelites, sandstones), La Toma Formation (marls), El Calabozo Formation (stromatolitic limestones with Conophyton), Gibraltar Formation (mainly dolostones, subordinate marls and limestones) and Nueva Carrara Formation (acid lapilli-tuffs acidos and dolomitic metamarls). Three outcrop areas are known, located between Minas and Pan de Azucar, namely: Mina Verdun (stratotype), Burgueno Quarry and Paso del Molino (Arroyo Pan de Azucar). Diamictites and orthoconglomerates of the Las Ventanas Formation overly with erosional and angular unconformity the Mina Verdun Group. The age of the succession is pre-Ediacaran, and bracketed between the late Mesoproterozoic and Tonian (1300-850 Ma) according to the chemostratigraphic data and the stromatolite assemblages. Carbonates of the Mina Verdun Group show a ?13C curve at its stratotype, which is characterized by a basal negative excursion to -3.3 PDB, followed by moderately positive values in the rest of the section, representing a plateau around +2 ? PDB. In the southern part of its outcrop area, limestones of the Mina Verdun Group show more negative de ?13C and ?18O values, as well as a maniphest decoloration. These characteristics are the result of contact-metamorphism of nearby granitic plutons in that area. (author)

  14. Curvas de titulación potencio métrica ácido-base de una bentonita

    Directory of Open Access Journals (Sweden)

    Liz Adriana Pinilla Cuenca

    2011-03-01

    Full Text Available Se estudió el comportamiento acido- base de una bentonita colombiana proveniente del Valle del Cauca, medianteexperimentos de titulación potenciométrica. Se escogió el método de titulación por retroceso, ya que la técnica de titulación continua no produce una curva única de valoración.La curva de titulación muestra tres puntos de inflexión, establecidos mediante los máximos en la curva derivada, envalores de pH de 4,8; 6,2 y 6,8, que indican tres tipos de sitios ácidos, identificados con los mecanismos de intercambioiónico presentes en la bentonita. El primer sitio ácido, y el más fuerte, se manifiesta como un mecanismo de sustitución de los iones interlaminares, de la estructura 2: 1, por iones H +. El segundo y el tercero son consecuencia de sitios de enlaces rotos o defectos de la red cristalina localizados en bordes y aristas, que originan sitios de acomplejamientosuperficial de dos tipos: silanol (=SiOH y aluminol (=A10H

  15. Digestibilidade pré-cecal diurna e noturna em equinos fistulados alimentados com diferentes concentrados

    Directory of Open Access Journals (Sweden)

    Alexandre Augusto de Oliveira Gobesso

    2009-12-01

    Full Text Available O objetivo deste trabalho foi determinar as possíveis diferenças entre períodos diurno e noturno dos coeficientes de digestibilidade parcial pré-cecal da matéria seca, matéria orgânica, amido, proteína bruta, fibra em detergente ácido e fibra em detergente neutro de diferentes dietas formuladas com concentrados energéticos à base de milho, aveia, sorgo e milho/aveia 50/50%. Foram utilizados quatro cavalos íleo-fistulados com 36±4 meses de idade, mestiços, machos, castrados, com peso médio de 308±32kg. O delineamento experimental foi um quadrado latino 4X4 (quatro tratamentos, quatro períodos. Houve diferenças entre os períodos diurno e noturno nas frações da matéria seca, matéria orgânica, amido, fibra em detergente ácido e fibra em detergente neutro no tratamento a base de milho, nas frações fibra em detergente acido e fibra em detergente neutro no tratamento com aveia, e na fibra em detergente ácido dos tratamentos com sorgo e milho/aveia 50/50%.

  16. Structures of nitrato-(2-hydroxybenzaldehydo) (2,2 Prime -bipyridyl)copper and nitrato-(2-hydroxy-5-nitrobenzaldehydo)(2,2 Prime -bipyridyl)copper

    Energy Technology Data Exchange (ETDEWEB)

    Chumakov, Yu. M. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Paladi, L. G. [Moldova State University (Moldova, Republic of); Antosyak, B. Ya.; Simonov, Yu. A. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Tsapkov, V. I., E-mail: vtsapkov@gmail.com [Moldova State University (Moldova, Republic of); Bocelli, G. [Institute of Materials for Electronics and Magnetism (Italy); Gulea, A. P. [Moldova State University (Moldova, Republic of); Ginju, D. [Alexandru Ioan Cuza University of Iasi (Romania); Palomares-Sanchez, S. A. [Autonomous University of San Luis Potosi (Mexico)

    2011-03-15

    Nitrato-(2-hydroxy-5-nitrobenzaldehydo)(2,2 Prime -bipyridyl)copper (I) and nitrato-(2-hydroxybenzaldehydo)(2,2 Prime -bipyridyl)copper (II) were synthesized and characterized by X-ray diffraction. The coordination polyhedron of the central copper atom in complex I can be described as a distorted tetragonal pyramid whose base is formed by the phenol and carbonyl oxygen atoms of the monodeprotonated 2-hydroxy-5nitrobenzaldehyde molecule and the nitrogen atoms of the 2,2 Prime -bipyridyl ligand and whose apex is occupied by the oxygen atom of the nitrato group. In the crystal structure, complexes I are linked by the acido ligands and the NO{sub 2} groups of the aldehyde molecule into infinite chains. In complex II, the central copper atom is coordinated by 2-hydroxybenzaldehyde, 2,2 Prime -bipyridyl, and the nitrato group, resulting in the formation of centrosymmetric dimers. The coordination polyhedron of the central copper atom can be described as a bipyramid (4 + 1 + 1) with the same base as in complex I. The axial vertices of the bipyramid are occupied by the oxygen atom of the nitrato group and the bridging phenol oxygen atom of the adjacent complex related to the initial complex by a center of symmetry. In the crystal structure, complexes II are hydrogen bonded into infinite chains.

  17. Learning Chemistry with candies

    Directory of Open Access Journals (Sweden)

    Rodríguez Rodríguez, José Manuel

    2011-11-01

    Full Text Available Las golosinas (caramelos, chicles, nubes, palotes, papas fritas, etc. nos gustan a casi todos y gozan de una imagen positiva, a pesar de sus efectos secundarios si no se consumen con moderación. Aprovechándonos de esa buena imagen y de la gran variedad de golosinas que existen en el mercado, hemos diseñado una serie de experimentos con los que podemos explicar distintos tipos de reacciones químicas (acido-base, oxidación-reducción, endotérmicas…, la actuación de un indicador e, incluso, podemos comparar cantidades de vitamina C. En todas las actividades se persigue explicar algún aspecto de la Química que, en general, el público desconoce, captando su atención, por ejemplo, mediante cambios de color espectaculares y con las golosinas como protagonistas. Así mismo, estas experiencias pueden emplearse como recursos didácticos para alumnos de 4o E.S.O. y Bachillerato, apoyando los contenidos teóricos del currículum.

  18. Radiochemical investigation of the coprecipitation of microamounts of some hydrolyzable elements with metal hydroxides and metal oxides. Pt. 5

    International Nuclear Information System (INIS)

    Plotnikov, V.I.; Safonov, I.I.

    1979-12-01

    Investigation of the coprecipitation of various amounts of iron (III) (between 1 μg and 3.5 mg) with hydroxides of Sn(IV), Ga, Th, Sc, Be, Cd, and Mg as a function of the pH value of the solution. It is shown that the precipitation of the iron (III) with the precipitates of the hydroxides of Be, Cd, Ga, and Sc, which are of lower acidity compared with the microcomponent, is preceded by an acido-basic reaction of Fe(III) with the ions of the macrocomponent. The beginning of this reaction has been observed to coincide with the occurrence of its primary hydrolytical forms in the solution. It is furthermore intensified with decreasing difference in the acidic properties of iron (III) and the other element taking part in the reaction. The neutral hydroxide complex Fe(OH) 0 3 is shown to be the principal coprecipitated form of the iron (III). The coprecipitation of microquantities of iron (III) with tin (IV) hydroxide has been chosen as an example to illustrate the effect of additions of Th, Sc, and Be ions equimolar to the collector. The observed quantitative increase of the microcomponent in the solution is suggested to mainly result from the decrease of the hydrolytical degree of precipitation of tin (IV) due to the interaction of the latter with the ions of impurities. (orig.) 891 RSH/orig. 892 HIS [de

  19. Diferenciación de ácido acetilsalicílico utilizando la técnica de espectroscopia Raman y el análisis de componentes principales

    Directory of Open Access Journals (Sweden)

    José Luis González-Sólis

    2012-07-01

    Full Text Available Recientemente la técnica de espectroscopia Raman ha sido aplicada en áreas como médicas, farmacéuticas y nanotecnología para determinar las concentraciones y diferencias en las soluciones de compuestos orgánicos e inorgánicos. En éste trabajo se analizaron las diferencias respecto a las concentraciones de los compuestos de una forma farmacéutica derivada del ácido acetilsalicílico comercial en forma de comprimido fabricado por 5 diferentes laboratorios. Los datos en bruto se obtuvieron a partir del acido acetil salicílico como principio activo, y 5 muestras de diferentes laboratorios fueron también analizadas. El bloque espectral se obtuvo utilizando un equipo de microscopia Raman Horiba-JY HR800 con una fuente de excitación de 830 nm y 17 mW de potencia. El algoritmo del PCA fue desarrollado en MatLab y aplicado al bloque espectral. Concluyendo que la aplicación de la espectroscopia Raman a la farmacología ofrece información sobre la efectividad farmacológica del ácido acetilsalicílico como analgésico y antipirético.

  20. Study of chemical and electrochemical properties of some elements in molten NaAlCl

    International Nuclear Information System (INIS)

    Bermond, Alain

    1976-01-01

    We describe a study of the electrochemical and chemical properties in molten mixtures of Aluminium Chloride-Sodium chloride, at 210 deg. C and the concept of acidity, related to chloride activity, is previously summarized. In a first part, the study of Mercury and Cadmium by means of electro-analytical techniques, states the Hg 2+ 2 , Hg 2+ , Cd 2+ 2 and Cd 2+ ions and their acid properties. Some diagrams Equilibrium potential vs acidity are the synthesis of these results. In a second part, it is shown that a nickel electrode is an indicator of the presence of oxide ions; from interpretation of electrochemical results, O 2 appears to behave, in terms of the chloro-acido-basicity concept, as a strong di-base, giving the solvated form AlOCl - 2 , or a strong tri-base giving AlOCl. A saturation effect by Al 2 O 3 appears when the oxide concentration is increased; the solubility of Al 2 O 3 versus acidity is determined from the electrochemical results. In a third part, results for the Ni/Ni(II) or HCl/H 2 O systems are related to dissolved oxide ion presence in chloroaluminate melts; elimination of oxide ions, through H 2 O formation, by reaction with HCl is noteworthy. (author) [fr

  1. Operation of the ISO-DALT system: Seventh edition

    International Nuclear Information System (INIS)

    Tollaksen, S.L.; Anderson, N.L.; Anderson, N.G.

    1984-05-01

    The ISO-DALT system of two-dimensional electrophoresis was developed as a series of modifications of the original technique of O'Farrell. We have written a series of recipes and more detailed laboratory procedures that incorporate refinements and ''tricks of the trade'' as they have developed during our use of the system. The present collection is the seventh version in this series and represents the state of art as of May 1984. The seventh edition has been prepared to incorporate the changes that we have found helpful, as well as to add a few new sections such as silver staining, transfer gels, ACIDOs, and BASOs. Although these directions are specific for our laboratory, we hope that they will be helpful in other laboratories as well. Although some disagreement still exists, we recommend that gel patterns be oriented with acid isoelectric points (pIs) to the left and high sodium dodecyl sulfate (SDS) molecular weights at the top. This results in a system of pI and molecular weight values that run according to the Cartesian convention and facilitates the use of the charge and molecular weight standards described herein. 67 refs., 14 figs

  2. An Assessment of those Metabolites Considered to be of Value in the Diagnosis of Exposure to Radiation; Evaluation des Metabolites Consideres Comme Utiles dans le Diagnostic des Expositions aux Rayonnements; 041e 0426 0414 ; Evaluacion de los Metabolitos Considerados Utiles para Diagnosticar la Exposicion a las Radiaciones

    Energy Technology Data Exchange (ETDEWEB)

    Smith, H.; Bates, T. H. [United Kingdom Atomic Energy Authority, Chapelcross, Annan, Scotland (United Kingdom)

    1965-06-15

    entre tres y cinco semanas. Mientras duro el tratamiento, se determino cuantitativamente la excrecion urinaria de los siguientes compuestos: creatinina, creatina, nitrogeno a-aminado total, acido {beta}-aminoisobutirico, acido pirrol-2-carboxflico, acido 5-hidroxi-indolacetico y sulfato de indoxilo. Si bien ninguno de los pacientes se sometio a una irradiacion del organismo entero, se comprobo que las modificaciones en la funcion metabolica que resultan de lesiones radioinducidas pueden reflejarse en la excrecion urinaria. Los autores examinan en la memoria las razones de orden bioquimico y la interpretacion de los esquemas de excrecion en relacion con la parte del organismo irradiada; pero, en el estado actual de las investigaciones, llegan a la conclusion de que no es posible evaluar cuantitativamente las lesiones biologicas. No obstante, esas pruebas pueden facilitar la eleccion de la terapia por el clinico. Los resultados de ensayos preliminares sobre las modificaciones experimentadas por determinados metabolitos plasmaticos en ratas expuestas a una sola dosis subletal de rayos X merecen ser extrapoladas y aplicadas a los estudios de casos humanos. Se han medido las concentraciones plasmaticas de las siguientes sustancias: 5-hidroxitriptamina, acido urico, transaminasa glutamo-oxalacetica, transaminasa glutamo-piruvica (ambas en el suero), fracciones globulfnicas, creatfn-fosfoquinasa, leucin-aminopeptidasa, lisil-aminopeptidasa, calicrefna, calidina, cinc y manganeso. Despues de la irradiacion se observaron considerables cambios de caracter cualitativo en la concentracion plasmatica de acido urico, leucin-aminopeptidasa, lisil-aminopeptidasa y manganeso. En la memoria se examina el significado de estos datos. En estos estudios se ha atribuido particular importancia a los procedimientos adoptados, que son sencillos y de aplicacion rapida. (author) [Russian] Izuchalis' nekotorye metabolity, vydelennye s mochej y ljudej, podvergnutyh rentgenovskomu i gamma

  3. Preparation of Ceramic-Grade Thorium-Uranium Oxide; Preparation d'un melange d'oxydes de thorium et d'uranium propre a la fabrication de combustible ceramique; Izgotovlenie keramicheskogo torievo-uranovogo okisla; Preparacion de mezclas de oxidos de uranio y torio, de tipo ceramico

    Energy Technology Data Exchange (ETDEWEB)

    Cogliati, G.; De Leone, R.; Ferrari, S.; Gabaglio, M.; Liscia, A. [Centro Studi Nucleari della Casaccia, Rome (Italy)

    1963-11-15

    de uranilo. Este metodo puede ser de utilidad para la elaboracion de elementos combustibles y para la regeneracion de los mismos. En la primera fase del metodo, el nitrato de uranilo se reduce a nitrato de uranio (IV). Como agente reductor se emplea acido formico e hidrogeno gaseoso; se anade urea para impedir la formacion de acido nitroso, que cataliza la reoxidacion del uranio (IV). En calidad de catalizadores pueden emplearse platino y paladio. Se facilitan datos relativos a un proceso continuo, en el que el acido formico y la urea se afladan a la solucion, que seguidamente se precalienta y se hace pasar a traves de una columna rellena de pastillas de alumina de 3,17 x 3,17 mm, que contienen 0,5% en peso de platino. Se estudia la influencia de la velocidad de circulacion, temperatura, concentraciones de acido formico y de urea, asi como la duracion y el envenenamiento del catalizador. La segunda fase del metodo consiste en la precipitacion de oxalato de torio y uranio (IV). Se estudia la influencia de la razon acido oxalico torio-uranio, de la temperatura y del tiempo de envejecimiento sobre las caracteristicas de sedimentacion y de filtracion del precipitado y sobre las propiedades ceramicas de los polvos obtenidos. El calentamiento se ha efectuado tanto en atmosfera reductora como oxidante. Luego de ensayos preliminares, se han establecido dos procedimientos normales para la elaboracion de cuerpos ceramicos, a saber, por prensado en frio y sinterizacion y por extrusion y sinterizacion. Las propiedades de sinterizacion de los diferentes polvos se han ensayado por los dos procedimientos normales. Con algunos de los polvos se han obtenido densidades superiores al 95% del valor teorico; se han realizado con exito ensayos de reproductibilidad. (author) [Russian] Issledovan protsess izgotovleniya spechennykh izdelij iz smesi torievo-uranovykh okislov, nachinayushchijsya s rastvoreniya nitrata toriya i nitrata uranila. Ehtot protsess mozhet okazat'sya poleznym kak dlya

  4. Mechanical behaviour of AlSiC nano composites produced by ball milling and spark plasma sintering =

    Science.gov (United States)

    Buchheim, Claudia Sofia de Andrade Redondo Murilhas

    Neste trabalho foram produzidos nanocompositos de AlSiC misturando aluminio puro com nano particulas de SiC com diâmetro de 45 - 55 nm, usando, de forma sequencial, a tecnica da metalurgia do po e a compactacao por "Spark Plasma Sintering". O composito obtido apresentava graos com 100 nm de diâmetro, encontrandose as particulas de SiC localizadas, principalmente, nas fronteiras de grao. O nanocomposito sob a forma de provetes cilindricos foi submetido a testes de compressao uniaxial e a testes de nanoindentacao para analisar a influencia das nanoparticulas de SiC, da fracao volumica de acido estearico e do tempo de moagem, nas propriedades mecânicas do material. Para efeitos de comparacao, utilizouse o comportamento mecânico do Al puro processado em condicoes similares e da liga de aluminio AA1050O. A tensao limite de elasticidade do nanocomposito com 1% Vol./Vol. de SiC e dez vezes superior a do AA1050. O refinamento de grao a escala nano constitui o principal mecanismo de aumento de resistencia mecânica. Na realidade, o Al nanocristalino sem reforco de particulas de SiC, apresenta uma tensao limite de elasticidade sete vezes superior a da liga AA1050O. A adicao de 0,5 % Vol./Vol. e de 1 % Vol./Vol. de SiC conduzem, respetivamente, ao aumento da tensao limite de elasticidade em 47 % e 50%. O aumento do tempo de moagem e a adicao de acido estearico ao po durante a moagem conduzem apenas a um pequeno aumento da tensao de escoamento. A dureza do material medida atraves de testes de nanoindentacao confirmaram os dados anteriores. A estabilidade das microestruturas do aluminio puro e do nanocomposito AlSiC, foi testada atraves de recozimento de restauracao realizado as temperaturas de 150 °C e 250 °C durante 2 horas. Aparentemente, o tratamento termico nao influenciou as propriedades mecânicas dos materiais, excepto do nanocomposito com 1 % Vol./Vol. de SiC restaurado a temperatura de 250 °C, para o qual se observou uma reducao da tensao limite de elasticidade

  5. Mathematical modeling of the hydrogen evolution reaction using HClO{sub 4} and H{sub 2}SO{sub 4} as electrolytes; Modelacion matematica de la reaccion de evolucion del hidrogeno utilizando HClO{sub 4} y H{sub 2}SO{sub 4} como electrolitos

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Chavez, Laura; Herrera Peraza, Eduardo; Alonso Nunez, Gabriel [Centro de Investigacion en Materiales Avanzados, Chihuahua, Chihuahua (Mexico); Manzanarez Papayanopoulos, Luisa [PROFEPA, Mexico D.F. (Mexico); Verde Gomez, Ysmael [Instituto Tecnologico de Cancun, Cancun, Quintana Roo (Mexico); Keer Rendon, Arturo [Centro de Investigacion en Materiales Avanzados, Chihuahua, Chihuahua (Mexico)

    2008-01-15

    tecnologia, se ha visto limitada por factores tales como el elevado costo de los distintos componentes que conforman una celda de combustible. Por ejemplo, el platino empleado por excelencia como el mejor catalizador para llevar a cabo la reaccion quimica entre hidrogeno y oxigeno, responsable de la produccion de energia electrica. En la busqueda de la optimizacion o sustitucion del platino, es importante contar con una metodologia que permita realizar un diagnostico in situ del estado de dicho catalizador. Este diagnostico involucra aspectos tales como la determinacion de los sitios activos y la carga y la degradacion que el catalizador puede ir sufriendo durante el funcionamiento de la celda. El presente trabajo consiste en el desarrollo de un modelo matematico que alimentado con las constantes de velocidad y los fenomenos involucrados en la reaccion de la evolucion del hidrogeno, produce como datos de salida, las curvas de polarizacion (E vs I) y de espectroscopia de impedancia electroquimica para dicha reaccion. Se considero para la modelacion, al Pt monocristalino preferenciado en las direcciones (111) y (100) como catalizador y usando diversos acidos como electrolitos. Las curvas obtenidas con el algoritmo matematico muestran una correlacion de la influencia del tipo y concentracion de los acidos usados como electrolitos y la densidad de corriente electrica debido a la evolucion del H{sub 2}. Finalmente, este modelo deja abierta la posibilidad de explorar el efecto del cambio en los valores de las variables involucradas en las reacciones de una celda de combustible, lo que nos permitira evaluar in situ el estado y comportamiento del catalizador.

  6. Production of C{sup 14}-labelled compounds from C{sup 14}O{sub 2} accelerated in an electric field - Physico-chemical analysis of some radioactive compounds obtained; Production de composes marques au {sup 14}C a partir de {sup 14}CO{sub 2} accelere dans un champ electrique - Analyse physico-chimique de quelques composes radioactifs obtenus; Proizvodstvo mechennykh uglerodom-14 soedinenij iz C{sup 14}O{sub 2}, uskorennogo v ehlektricheskom pole - Fiziko-khimicheskij analiz neskol'kikh poluchennykh radioaktivnykh soedinenij; Obtencion de compuestos marcados con {sup 14}C a partir de {sup 14}CO{sub 2} acelerado en un campo electrico - Analisis fisicoquimico de algunos de los compuestos radiactivos obtenidos

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume, M [Universite de Liege, Belgique (Belgium)

    1962-03-15

    con cadenas alifaticas (50 {mu}c/g para el acido glutarico) o con moleculas ciclicas que presenten una cadena alifatica (acido acetilsalicilico). (author) [Russian] V dannoj rabote izlagaetsya metod mecheniya, osnovannyj na uskorenii ehlektricheskim polem C{sup 14}O{sub 2}, kotoryj v ehto vremya poddaetsya vstupleniyu v reaktsiyu s organicheskoj mishen'yu, nakhodyashchejsya na ego traektorii. Opysyvaemaya razryadnaya kamera dejstvuet pod napryazheniem 500 v, 150 mka, a podlezhashchie mecheniyu organicheskie veshchestva vvodyatsya v ehto pole i nakhodyatsya tam okolo 3 chasov vmeste s CO{sub 2} udel'noj aktivnosti v 24 mkyuri/mmol'. Maksimal'nyj vykhod poluchennykh produktov ostaetsya slabym (okolo 6%), a 60% C{sup 14}O{sub 2} - razrusheno. EHtot maksimal'nyj vykhod poluchaetsya tol'ko dlya alifaticheskikh tsepej (50 mkkyuri/r dlya glutarovoj kisloty) ili dlya aromaticheskikh veshchestv, predstavlyayushchikh alifaticheskuyu tsep' (atsetilgalitsilovuyu kislotu). (author)

  7. Investigations on the nature and physical concentration of Spanish uraniferous quartzites; Estudios de caracterizacion y concentracion fisica de cuarcitas uraniferas espanolas

    Energy Technology Data Exchange (ETDEWEB)

    Lora, F de [Direccion de Plantas Piloto e Industriales, Junta de Energia Nuclear, Madrid (Spain)

    1967-06-15

    A study was made of a sample of radioactive material from Santa Elena (Jaen) containing 130 ppm U{sub 3}O{sub 8}, 300 ppm ThO{sub 2}, 4.96% ZrO{sub 2} and 14.29% TiO{sub 2}. Over 150 million tons of material were examined. In the light of the studies carried out the material can be defined as a rutilo-zirconiferous quartzite with a double radioactivity source due to the uranium enclosed in the zircon lattice structure and to the presence of monazite. The possibility of brannerite or davidite being present can be discarded. There is likewise no conclusive evidence of the presence of sphene, rutile being the most abundant titanium mineral. The author determined the features of the ore with a view to its physical concentration and applied magnetic and gravimetric separation and the flotation process. The use of oleic acid as collector has permitted good zircon recovery. (author) [Spanish] Se ha estudiado una muestra de material radiactivo procedente de Santa Elena (Jaen) con 130 ppm de U{sub 3}O{sub 8}, 600 ppm de ThO{sub 2}, 4,96% de ZrO{sub 2} y 14,29% de TiO{sub 2}. El material examinado es considerable: mas de 150 millones de toneladas. De acuerdo con los estudios realizados se puede definir como una cuarcita rutilo-circonifera con dos fuentes de radiactividad debidas al uranio englobado en la red del circon y a la presencia de monacita. Se descarta la posibilidad de existencia de brannerita o davidita. Tampoco existen pruebas concluyentes de que contenga esfena, siendo el ratilo el mineral de titanio mas abundante. Se han determinado las caracteristicas de la mena con vistas a su concentracion fisica. Se ha ensayado la separacion magnetica, gravimetrica y flotacion. El empleo de acido oleico, como colector, ha dado buenas recuperaciones de circon. (author)

  8. Autoradiographic Study of Incorporation of Tritiated Thymidine in the Rat; Etude Autoradiographique de l'Incorporation de Thymidine Tritiee chez le Rat; 0420 0430 0434 0438 043e 0430 0432 0442 043e 0414 ; Estudio Autorradiografico de la Incorporacion de Timidina Tritiada en la Rata

    Energy Technology Data Exchange (ETDEWEB)

    Maldague, P.; Hong-Que, Pham; Maisin, J. [Laboratoire de Radiobiologie, Institut du Cancer, Louvain (Belgium)

    1962-02-15

    The authors used tritiated thymidine to evaluate desoxyribonucleic acid synthesis in various rat organs. They show by autoradiographs that this synthesis takes place mainly in tissue having intensive mitotic activity (bone marrow, seminiferous tubules of the testis, mucous membrane of the intestine, oesophagus and tongue). The authors also studied the regeneration of the convoluted renal tubules during the months following local irradiation of the kidney at various doses. (author) [French] Les auteurs ont utilise de la thymidine tritiee pour evaluer la synthese de l'acide desoxyribonucleique au niveau de differents organes chez le rat. Ils montrent par autoradiographies que cette synthese s'effectue principalement au niveau des tissus presentant une activite mitotique intense (moelle osseuse, tubes seminiferes du testicule, muqueuse intestinale, oesophagienne et de la lingue). Les auteurs ont en outre etudie la regeneration des tubes contournes du rein apres irradiation locale de cet organe, a differentes doses et dans les mois qui suivent cette irradiation. (author) [Spanish] Los autores han utilizado timidina tritiada para evaluar la sintesis del acido desoxirribonucleico en distintos organos de la rata. Demuestran mediante autorradiografias que esta sintesis se produce principalmente en los tejidos de intensa actividad mitotica (medula osea, tubos seminiferos de los testiculos, mucosas intestinal, del esofago y de la lengua). Finalmente, los autores han estudiado la regeneracion de los tubos y convolvulados del rinon en los meses que siguen a la irradiacion local de este organo con distintas dosis. (author) [Russian] Avtory pol'zovalis' mechennym tritiem timidinom dlja ocenki sin- teza dezoksiribonukleinovoj kisloty v razlichnyh organah krysy. Pri po- moshhi radioavtografii avtory pokazyvajut, chto jetot sintez proishodit glavnym obrazom v tkanjah s intensivnoj mitoticheskoj dejatel'nost'ju (kostnyj mozg, semenenosnye kanaly testikula, slizistaja obolochka

  9. Indagine su un focolaio di tossinfezione da Salmonella enterica subsp. enterica serovar Hadar nella regione Abruzzo

    Directory of Open Access Journals (Sweden)

    Primula Semprini

    2008-06-01

    Full Text Available E’ stato eseguito uno studio comparativo tra 22 ceppi di Salmonella Hadar isolati da soggetti coinvolti in un focolaio di tossinfezione alimentare in Abruzzo nel 2000 e 21 ceppi dello stesso sierotipo isolati da carni avicole e da feci umane in Abruzzo e Molise nel periodo 2000 e 2001. L’indagine aveva come obiettivo di fornire una interpretazione epidemiologica del focolaio di tossinfezione alimentare determinando il grado di similarità tra i ceppi di Salmonella Hadar isolati dai soggetti coinvolti nel focolaio, quelli isolati da carne avicola, identificata ma non confermata come possibile fonte di infezione, e da altri campioni umani pervenuti in laboratorio. A tal fine sono state impiegate tecniche di caratterizzazione genotipica come pulsed-field gel electrophoresis (PFGE e random amplified polymorphic DNA (RAPD e sono stati determinati i pattern di resistenza agli antimicrobici. Dall’analisi in PFGE dei profili di restrizione ottenuti con XbaI e BlnI sono stati identificati 12 pulsotipi suddivisi in 3 gruppi. La RAPD non ha fornito indicazioni non riuscendo a discriminare i ceppi isolati dai soggetti con gastroenterite appartenenti al focolaio tossinfettivo. Il test di resistenza agli antimicrobici ha evidenziato pattern di resistenza multipla ma non sono stati identificati ceppi resistenti al Ciprofloxacin o altri Chinoloni testati. I ceppi aviari sono risultati resistenti all’acido nalidixico mentre solo il 31,8% di quelli umani ha presentato tale profilo. Da un’analisi combinata dei pattern di resistenza e dei pulsotipi sono stati identificati 4 profili di cui quello associato al focolaio è risultato non correlato agli altri presenti nello stesso periodo. E’ stata confermata la necessità di applicare un set di metodi di analisi differenti per garantire una migliore caratterizzazione e una maggiore capacità discriminante nell’identificazione delle possibili origini della contaminazione e stabilire correlazioni fra gli

  10. Study of Np speciation in citrate medium

    Energy Technology Data Exchange (ETDEWEB)

    Bonin, L.; Den Auwer, C.; Ansoborlo, E.; Moisy, P. [CEA Valrho - DEN/DRCP/SCPS, Bagnols sur Ceze (France); Cote, G. [ENSP - LECA, UMR 7575, Paris (France)

    2007-07-01

    In the framework of the French Environmental Nuclear Toxicology program, additional experiments related to the decorporation of actinides are planned. Decorporation is the removal or release from target organs (bones, liver, kidney..), tissues or cells of radioactive material previously incorporated in them, using chelating agents or other administrated pharmaceutical agents. The contradictory data on the neptunium complexation behaviour within blood and its transfer to target organs, as well as the inefficiency of therapeutic treatments, led us to study the complexation of this element with biological constituents. Within this purpose, the in vitro behaviour of Np(IV) and Np(V) in simple media simulating biological fluids was studied. This study was more specifically focused on the behaviour of neptunium with citrate ion, which is an essential component in a number of metalloenzyme active sites. In order to determine the speciation of this system, spectrophotometry was more particularly used. Concerning the complexation phenomenon, the existence of several complexes of Np(V) with various acido-basic forms of the citrate anion was observed; regarding Np(IV), complexes with Cit{sup 3-} have been observed. From the quantitative study of these equilibria, the values of the absolute constants for the complexation of Np(IV) and Np(V) with citrate were determined. Concerning the stability of neptunium towards oxydo-reduction, it was confirmed that Np(VI) was very quickly reduced to Np(V) by the citrate anions, whereas Np(IV) was stable. In the case of Np(V), it was observed that, depending on the pH and the citrate concentration, Np(V) was unstable and was reduced to Np(IV). The E-pH diagrams, constructed using the stability constants determined in this study, showed that this instability was due to the Np(V) disproportionation. (orig.)

  11. Pyrochemical reprocessing of molten salt fast reactor fuel: focus on the reductive extraction step

    Directory of Open Access Journals (Sweden)

    Rodrigues Davide

    2015-12-01

    Full Text Available The nuclear fuel reprocessing is a prerequisite for nuclear energy to be a clean and sustainable energy. In the case of the molten salt reactor containing a liquid fuel, pyrometallurgical way is an obvious way. The method for treatment of the liquid fuel is divided into two parts. In-situ injection of helium gas into the fuel leads to extract the gaseous fission products and a part of the noble metals. The second part of the reprocessing is performed by ‘batch’. It aims to recover the fissile material and to separate the minor actinides from fission products. The reprocessing involves several chemical steps based on redox and acido-basic properties of the various elements contained in the fuel salt. One challenge is to perform a selective extraction of actinides and lanthanides in spent liquid fuel. Extraction of actinides and lanthanides are successively performed by a reductive extraction in liquid bismuth pool containing metallic lithium as a reductive reagent. The objective of this paper is to give a description of the several steps of the reprocessing retained for the molten salt fast reactor (MSFR concept and to present the initial results obtained for the reductive extraction experiments realized in static conditions by contacting LiF-ThF4-UF4-NdF3 with a lab-made Bi-Li pool and for which extraction efficiencies of 0.7% for neodymium and 14.0% for uranium were measured. It was concluded that in static conditions, the extraction is governed by a kinetic limitation and not by the thermodynamic equilibrium.

  12. Monitoring and control system for the charging of batteries in photovoltaic applications; Sistema para monitorizar y controlar la carga de baterias en aplicaciones fotovoltaicas

    Energy Technology Data Exchange (ETDEWEB)

    Ortega S, Cesar A; Pacheco A, Maria Jojutla; Orozco V, Jaime A; Cristin V, Miguel A [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2004-07-01

    The appropriate monitoring and control of the charging of lead-acid (LAB) batteries is an increasing necessity in an industry that demands systems with low maintenance costs and high availability. The problem of extending the batteries useful life becomes more complex when the batteries are charged through photovoltaic panels. The purpose of the present article is to offer the description of the system for monitoring and control for the charging of batteries developed at the Instituto de Investigaciones Electricas (IIE). This system performs a continuous monitoring of the charging state of the battery and of the main operation parameters. With the extracted information of the data, the fine tuning algorithm control can be made. The data are acquired in a personal computer through a serial connection. Once stored, they are presented to the user in a graphical way so that they can be analyzed. [Spanish] El adecuado monitoreo y control de carga de baterias plomo-acido (BPA) es una necesidad creciente en una industria que demanda sistemas con bajos costos de mantenimiento y alta disponibilidad. El problema de extender la vida util de las baterias se vuelve mas complejo cuando las baterias son cargadas a traves de paneles fotovoltaicos. La intencion del presente articulo es ofrecer la descripcion del sistema para monitoreo y control de carga de baterias desarrollado en el Instituto de Investigaciones Electricas (IIE). Este sistema realiza un monitoreo continuo del estado de carga de la bateria y de los principales parametros de operacion. Con la informacion extraida de los datos, se puede hacer la sintonizacion fina del algoritmo de control. Los datos se adquieren en una computadora personal a traves de un enlace serial. Una vez almacenados, se presentan al usuario de manera grafica para que puedan ser analizados.

  13. Efecto citoprotector del camu-camu Myrciaria dubia en tres líneas celulares de ratón expuestos in vivo a bromato de potasio

    Directory of Open Access Journals (Sweden)

    Alvis Rafael

    2011-05-01

    Full Text Available Se evaluó in vivo la capacidad citoprotectora del fruto de Myrciaria dubia (Kunth McVaugh Camu-camu frente al daño mutagénico producido por bromato de potasio (68,5 mg/k sobre tres líneas celulares de ratón (hígado, riñón y células sanguíneas. Se utilizó ratones (n= 120 divididos en tres grupos los cuales bebieron ad libitum: TI= control negativo (solo agua y el grupo TIII (control positivo; El grupo TII bebió el extracto acuoso (2% p/v del fruto de camu-camu. A los diez días se inyectó una dosis única de KBr03 (68,5 mg/kg peso corporal vía intraperitoneal, a los grupos TII y TIII. El tratamiento con camu-camu continuo 35 días más, luego los ratones fueron eutanizados para determinar la frecuencia del daño al DNA mediante el protocolo del ensayo cometa alcalino. El grupo TII mostró en todas las líneas celulares el efecto citoprotector del camu-camu (p< 0,05. El efecto dañino al DNA por la acción oxidativa del KBrO3 es inhibido por el extracto acuoso del fruto de camu camu, probablemente por la presencia de los agentes antioxidantes como el Acido ascórbico y los flavonoides.

  14. Avaliação da atividade antioxidante e antimicrobiana do extrato etanólico bruto e frações orgânicas obtidas a partir da casca do caule da espécie Guettarda uruguensis Cham, & Scthdl, (Rubiaceae

    Directory of Open Access Journals (Sweden)

    Ana Flávia Schvabe Duarte

    2014-09-01

    Full Text Available Este trabalho teve como objetivo avaliar o potencial antioxidante e antimicrobiano do extrato bruto e frações obtidas das cascas do caule da espécie Guettarda uruguensis, Os ensaios antioxidantes indicaram alto potencial antioxidante, No ensaio de redução de fosfomolibdênio, a fração acetato de etila apresentou atividade antioxidante de 41,67% em relação ao padrão de ácido ascórbico e superou em 35,21% a atividade do padrão rutina, No ensaio de redução do DPPH (2,2-diphenyl-1-picrylhydrazyl, a fração acetato de etila apresentou um IC50 de 10,91 µg mL-1, valor próximo ao do ácido ascórbico (IC50 = 4,78 µg mL-1 e da rutina (IC50 = 6,62 µg mL-1, Pelo ensaio de TBA (acido tiobabitúrico o extrato bruto (IA = 71,48% e a fração hexano (IA = 47,85% apresentaram índices superiores ao controle de BHT (butil hidroxi tolueno (IA = 42,66, Através do ensaio de microdiluição em placas, foi observado que o extrato bruto e frações apresentaram atividade antimicrobiana, O estudo fitoquímico qualitativo revelou a presença de alcaloides, cumarinas, esteroides e/ou triterpenos, heterosídeos saponínicos, taninos e aminogrupos.

  15. The Villas Carrousel PV-Wind Hybrid Project

    Energy Technology Data Exchange (ETDEWEB)

    Huacuz, Jorge M. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    A pilot project was carried out to supply electrical services for an ecological hotel (eco-hotel), using solar and wind energy in Southeast Mexico. Fifteen small photovoltaic-wind hybrid systems were designed and built by researchers of the Electrical Research Institute of Mexico (IIE), as part of a cooperation agreement with the mexican company Carrousel Operadora Turistica, aimed at developing a technology package to supply electrical services to similar hotels sited in remote areas. Each hybrid system includes one wind generator of 500W nominal capacity, one PV panel ranging in power from 150W to 320 Watts peak, one lead-acid battery bank of 570 ampere-hour in capacity, and an electronic charge controller. This paper describes the systems and summarizes the results from the first twelve months of operation. [Espanol] Se llevo a cabo un proyecto piloto para el suministro de servicios electricos a un hotel ecologico (eco-hotel), utilizando energia solar y energia del viento en el Sudeste de Mexico. Investigadores del Instituto de Investigaciones Electricas de Mexico, disenaron y construyeron quince pequenos sistemas hibridos fotovoltaicos-viento, como parte de un acuerdo de cooperacion con la compania mexicana Carrousel Operadora Turistica, orientado al desarrollo de un paquete tecnologico para proporcionar servicios de energia electrica a hoteles similares ubicados en areas remotas. Cada sistema hibrido incluye un aero-generador con capacidad nominal de 500W un panel foto-voltaico con una potencia que varia entre los 150W y los 320W pico, una banco de baterias de plomo-acido de 570 amperes-hora de capacidad y un controlador electronico de carga. Este articulo describe los sistemas y presenta un resumen de los resultados de los primeros doce meses de operacion.

  16. Evaluation of a process for the removal of gases contained in geothermal steam through condensation and re-evaporation; Evaluacion de un proceso de remocion de gases contenidos en el vapor geotermico, por medio de la condensacion y de revaporacion

    Energy Technology Data Exchange (ETDEWEB)

    Angulo C, Raul; Lam Rea, Luis; Garmino, Hector; Jimenez, Humberto [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    The Cerro Prieto I Geothermal Field, developed and operated by the Comision Federal de Electricidad (CFE), has currently an installed electric power generation capacity of 180 MW and is at a very advanced stage in the development of Cerro Prieto II and III, which will allow to raise the generation capacity to 620 MW. During the exploitation of a geothermal field, in producing steam with the purpose of generating electricity, brines and waste gases are obtained. The hydrogen sulfide exhaust to the environment implies pollution problems, for this reason processes have been developed for the oxidation of these gases downstream the turbogenerator either in the flow of separated gases in the steam condensation or in the condensate produced. The Instituto de Investigaciones Electricas (IIE) has collaborated with CFE in the evaluation of the environmental impact of this gas and in the development of the processes for its abatement. [Espanol] El campo geotermico de Cerro Prieto I, desarrollado y operado por la Comision Federal de Electricidad (CFE), actualmente tiene una capacidad instalada de generacion de energia electrica de 180 MW, y se encuentra en etapa muy avanzada, el desarrollo de Cerro Prieto II y III, lo que permitira incrementar la capacidad de generacion a 620 MW. Durante la explotacion de un campo geotermico, al producir vapor con el proposito de generar electricidad, se obtienen salmueras y gases de desecho. La descarga de acido sulfhidrico a la atmosfera implica problemas de contaminacion, por esta razon se han desarrollado procesos para la oxidacion de este gas aguas abajo de la turbina generadora, ya sea en la corriente de gases que se separan en la condensacion del vapor o en el condensado producido. El Instituto de Investigaciones Electricas (IIE) ha colaborado con la CFE en la evaluacion del impacto ambiental de este gas y en el desarrollo de sus procesos de abatimiento.

  17. Contribution to the study of sorption mechanisms at solid-liquid interfaces: application to the cases of apatites and oxy-hydroxides; Contribution a l'etude des mecanismes de sorption aux interfaces solide-liquide: application aux cas des apatites et des oxy-hydroxydes

    Energy Technology Data Exchange (ETDEWEB)

    Duc, M

    2002-11-15

    Sorption-desorption phenomena play an important role in the transport of toxic and radioactive elements in surface and underground water in contact with solid matter. Selenium, which is one of the long-lived radionuclides present in radioactive waste, is characterized by several oxidation states and by anionic species in aqueous solutions. In order to predict its transport, we need a good knowledge of its sorption processes. We have studied the sorption of Se(IV) and Se(VI) on two types of solids present in natural media or which have been proposed as additives to active barriers: hydroxy-apatites, fluoro-apatite and iron oxi-hydroxides (goethite and hematite). Sorption mechanisms have been studied through an approach including several different and complementary methods: titrimetry, zeta-metry, scanning and transmission electron microscopy, infrared spectroscopy, X-ray diffraction, X-ray photo electron spectroscopy, etc... Results showed that Se(VI) is much less sorbed than Se(VI) on both types of solids. For Se(IV) the sorption mechanisms are different for iron oxides and apatites. On oxides, sorption increases when pH decreases. It can be interpreted by a surface complexation model, essentially through an inner sphere complex (monodentate or bidentate). Modelling of Se sorption curves was performed after the determination of acido-basic properties of oxides. However, the determination of the intrinsic properties of oxides is disturbed by several parameters identified as impurities, evolution of the solid in solution, kinetic and solubility of the solid. For apatites, selenium sorption proceeds by exchange with superficial groups, with a maximum of fixation at approximately pH 8. Thanks to XPS measurements and the elaboration of a mathematical model, we could determine the depth of penetration of both selenium and cadmium on apatites. (author)

  18. Una nueva especie de Euglena (Euglenozoa: Euglenales aislada de ambientes extremófilos en las Pailas de Barro del Volcán Rincón de la Vieja, Costa Rica

    Directory of Open Access Journals (Sweden)

    Ana Sittenfeld

    2004-03-01

    Full Text Available Se describe una nueva especie de euglena aislada de las Pailas de Barro Caliente del Volcán Rincón de la Vieja, Costa Rica. Esta especie se caracteriza por habitar sitios ácidos y calientes. Euglena pailasensis sp. nov. tiene como características principales: la ausencia de flagelos, presencia de filamentos similares a "pilis", presencia de cloroplastos con pirenoides atravesados por varios tilacoides, además, es termotolerante y acido-tolerante. Los análisis filogenéticos para el gen ADNr 18S y la secuencia del gen para la enzima Gap C indican que la nueva especie está relacionada con E. mutabilis. Las características taxonómicas basadas en la morfología, biología y secuencia del ADNr 18S y los genes GAP C, son discutidas y comparadas con otras especies relativamente cercanas al géneroAnew species of euglena isolated from a hot and acid mud pool located in Las Pailas de Barro, Volcán Rincón de la Vieja, Costa Rica is described. This species inhabits hot and acid environments. Euglena pailasensis sp. nov. main features are: the absence of flagella, the presence filaments like "pilis", the presence of chloroplasts with pyrenoids crossed by several tylakoids, and acid and heat tolerance. Molecular phylogeny studies using 18S rDNA and Gap C genes indicated that the new species is related to E mutabilis. Its taxonomic characters based on morphology, biology and sequence of the 18S rDNA and Gap C genes are discussed and compared with other closely related species of the genus

  19. Micro-organisms and divers exposure to radioactivity in spent fuel pools at nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Muniz de A, D. [Underwater Construction Corporation, Latin America, Fortaleza, Ceara (Brazil); Silva, R. [Universidade Federal do Rio de Janeiro, Instituto de Biofisica Carlos Chagas Filho, 21941-902 Rio de Janeiro (Brazil); Gomes N, C. A., E-mail: dmuniz@uccdive.com [Universidade Federal do Rio de Janeiro, Instituto de Biologia, Environmental Engineering Program, 21941-902 Rio de Janeiro (Brazil)

    2017-09-15

    Many nuclear power plants (NPPs) around the world are in the process of extending their lifespan from 40 to 60 years of operation. The NPP; Angra 1 (Brazil) has performed a thorough evaluation of its Life Extension Engineering project. In this context, the spent fuel pool (SFP) was one of the areas studied in order to demonstrate the plants integrity for a life extension. Micro-organisms growing on the liner of the fuel transfer channel (Ftc) and SFP can form a film of bacteria, which is highly resistant to radiation. This paper aims to compare the micro-organisms found in NPP Angra 1 with those reported to other NPPs and also relates their occurrence with the radiation levels at the sites. It also compares divers exposure to radioactivity during underwater activities in the SFP. Fourteen samples were collected on the surface of the liners of the Ftc, the SFP and the drains within the fuel building (FB) of Angra 1. For the identification of the micro-organisms, a metagenomics analysis was performed by random sequencing (Shotgun) and the use of Ion Torrent PGM Sequence r. Twelve micro-organisms phyla were identified; Acido-bacteria, Actino-bacteria, Bacteroidetes, Chlamydiae, Chlorobi, Chloroflexi, Cyano-bacteria, Deinococcus-Thermus, Firmicutes, Planctomycetes, Proteo-bacteria, and Verrucomicrobia as well as organisms not classified. In the SFP of Angra 1, the bacteria survived the exposure to a radiation of 0.416 Gy/h (high radiation). Deinococcus-thermus, bacteria identified in Angra 1, has resisted an exposure to 30,000 Gy/h in another plant. (Author)

  20. Asymmetric electrooptic response in a nematic liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Dascalu, Constanta [Politechnica University of Bucharest, Bucharest (Romania)

    2001-06-01

    An asymmetric electrooptic response in nematic liquid crystal (LC) has been obtained. The liquid crystal hybrid cell was made by using a standard configuration. One of the ITO (Indium Tin Oxide) electrodes was covered with a surfactant, which induces a homeotropic alignment. The second of the indium tin oxide electrodes was covered by a thin layer of photopolymer, which was previously mixed with an acid, which favours a process of release of protons. Such cations are responsible of electrochemical process in the LC leading to an asymmetric electrooptic response, which depend on the polarity of the applied electric field. This fact is due to an internal field, which change the effective voltage thresholds for the reorientation of the liquid crystal. During the anodic polarization, the optical switching is inhibited because the effective field decreases below the threshold value. On contrary for the opposite polarization the effective field is enough to determine a homeotropic alignment. [Spanish] Se ha obtenido una respuesta electro-optica asimetrica en cristales liquidos neumaticos. La celula hibrida de cristal liquido fue construida utilizando una configuracion estandar. Uno de los electrodos ITO fue cubierto con una pelicula delgada de material organico para inducir una alineacion homeotropa. El otro electrodo ITO fue cubierto con una pelicula delgada de fotopolimero anteriormente mezclada con un acido para favorecer la emision de protones. Estos cationes son responsables del proceso electroquimico en LC, conduciendo a una respuesta electro-optica asimetrica que depende de la polaridad del campo electrico aplicado. Este efecto es originado por un campo interno que cambia el umbral efectivo del voltaje para la reorientacion del cristal liquido. Durante la polarizacion anodica, la conmutacion optica se inhibe debido a que el campo efectivo disminuye abajo del valor del umbral. Por el contrario, para la polarizacion opuesta el campo efectivo es suficiente para

  1. Contribution to the study of sorption mechanisms at solid-liquid interfaces: application to the cases of apatites and oxy-hydroxides

    International Nuclear Information System (INIS)

    Duc, M.

    2002-11-01

    Sorption-desorption phenomena play an important role in the transport of toxic and radioactive elements in surface and underground water in contact with solid matter. Selenium, which is one of the long-lived radionuclides present in radioactive waste, is characterized by several oxidation states and by anionic species in aqueous solutions. In order to predict its transport, we need a good knowledge of its sorption processes. We have studied the sorption of Se(IV) and Se(VI) on two types of solids present in natural media or which have been proposed as additives to active barriers: hydroxy-apatites, fluoro-apatite and iron oxi-hydroxides (goethite and hematite). Sorption mechanisms have been studied through an approach including several different and complementary methods: titrimetry, zeta-metry, scanning and transmission electron microscopy, infrared spectroscopy, X-ray diffraction, X-ray photo electron spectroscopy, etc... Results showed that Se(VI) is much less sorbed than Se(VI) on both types of solids. For Se(IV) the sorption mechanisms are different for iron oxides and apatites. On oxides, sorption increases when pH decreases. It can be interpreted by a surface complexation model, essentially through an inner sphere complex (monodentate or bidentate). Modelling of Se sorption curves was performed after the determination of acido-basic properties of oxides. However, the determination of the intrinsic properties of oxides is disturbed by several parameters identified as impurities, evolution of the solid in solution, kinetic and solubility of the solid. For apatites, selenium sorption proceeds by exchange with superficial groups, with a maximum of fixation at approximately pH 8. Thanks to XPS measurements and the elaboration of a mathematical model, we could determine the depth of penetration of both selenium and cadmium on apatites. (author)

  2. Actividad antioxidante de compuestos naturales nitrogenados

    Directory of Open Access Journals (Sweden)

    Maestro-Durán, R.

    1993-06-01

    Full Text Available As a continuation of the study of natural antioxidants, this third part deals with nitrogeneous compounds, classified in the following groups.

    Amino acids and proteins.
    Products of the Maillard reaction.
    Phospholipids (with choline or ethanolamine and their heating products.
    Riboflavin.
    Chlorophylls and porphyrins.
    Uric acid and derivatives.
    Their behaviour as inhibitors of the chain reaction of prooxidant radicals, by irreversible reaction or by sequestration of those radicals, as well as their synergistic action with primary antioxidants is discussed. Finally, the patents registered during the last years for these kind of compounds, their derivatives and synergists in food and other uses are cited.

    Continuando el estudio de los antioxidantes naturales, se incluyen en esta tercera parte los compuestos nitrogenados, clasificados en los siguientes grupos:
    Aminoácidos y proteínas.
    Productos de la reacción coloreada de Maillard.
    Fosfolípidos (con las bases colina y etanolamina y sus productos de calentamiento.
    Riboflavina.
    Clorofilas y porfirinas.
    Acido úrico y sus derivados.
    Se discute su comportamiento como inhibidores de la reacción en cadena de los radicales prooxidantes, por reacción irreversible o por secuestro de estos radicales, así como su acción sinergista con antioxidantes primarios. Finalmente, se citan las patentes registradas en los últimos años para estos tipos de compuestos, sus derivados y sinergistas, en productos alimentarios o en otros usos.

  3. Effects of some sesquiterpenes on the stored-product insect Tenebrio molitor (Coleoptera: Tenebrionidae Efectos de algunos sesquiterpenos sobre el insecto de productos almacenados, Tenebrio molitor (Coleoptera: Tenebrionidae

    Directory of Open Access Journals (Sweden)

    Matías García

    2003-12-01

    Full Text Available In order to evaluate the allelochemical activity of some sesquiterpenes isolated from the native plant Tessaria absinthioides (Hook. et Arn. DC, and some semi synthetic derivatives against Tenebrio molitor L. larvae, we have developed bioassays directed to quantify repellency, larval mortality, and its effects on the development. Although costic aldehyde caused the maximum repellent effect, all the compounds showed a significant effect at some dose or time, indicating behavioral avoidance. The topical application of costic aldehyde produced the largest increase on the duration of the pupal stage. Tessaric acid exhibited the highest toxicity by topical application at the experiment closure. Both eremophilane-1(10,2,11(13-triene-12-oic, and -costic acids induced some morphological deformities.Con el objeto de evaluar sesquiterpenos aislados de la planta nativa Tessaria absinthioides (Hook et Arn y algunos derivados semisintéticos frente a larvas de Tenebrio molitor L., se desarrollaron bioensayos orientados a la cuantificación de la repelencia, mortalidad de larvas y efectos sobre el desarrollo. Aldehído cóstico produjo el mayor incremento en la duración del estado pupal por aplicación tópica. Acido tessárico exhibió el más alto porcentaje de mortalidad al finalizar el período de experimentación. Los productos eremophilan-1(10,2, 11(13-trien-12-oico y ácido -cóstico dieron lugar al mayor número de malformaciones. Si bien aldehído cóstico mostró la máxima actividad de repelencia, todos los compuestos evaluados produjeron efectos significativos en el ensayo de elección.

  4. CO{sub 2} electroreduction: conversion into formic acid and mechanistic aspect in aqueous medium; Electroreduction du CO{sub 2}: conversion en acide formique et aspect mecanistique en milieu aqueux

    Energy Technology Data Exchange (ETDEWEB)

    Innocent, B.; Pasquier, D.; Ropital, F. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Hahn, F.; Leger, J.M.; Kokoh, B. [Poitiers Univ., LaCCO, Equipe Electrocatalyse, UMR 6503 CNRS, 86 (France)

    2007-07-01

    The CO{sub 2} release reduction is nowadays considered as a necessity to limit the climatic change phenomena due to the greenhouse effect. For that, a part of CO{sub 2} could be transformed by its electrochemical reduction on a hydrogen overvoltage electrode as lead. According to the nature of the electrode material and of the electrolyte, CO{sub 2} can be electro catalytically hydrogenated or dimerized. In the conditions presented here (basic aqueous medium, lead electrode), the reagent is in majority reduced into formate, the parasite faradic reaction being the solvent transformation into dihydrogen. The studies carried out by cyclic voltametry have shown that the reducible form of CO{sub 2} is the hydrogeno-carbonate ion; its reduction begins at -1.2 V and reaches a maximum for an electrode potential of -1.6 V vs. ECS. Long intentiostatic electrolyses have then been carried out in an electrolytic circulation cell of 'filter-press' type. The cathode is a lead sheet of 20 cm{sup 2} and a current intensity of -100 mA has been imposed. The chromatographic analyses of the electrolytic solution have allowed to show that the formate selectivity is of 90%. The electroreduction process induces an acido-basic disequilibrium which induces a decrease of the reaction yield. A pH correction is then necessary to obtain great conversions of CO{sub 2} in alkaline medium (pH{>=}7) as follows: HCO{sub 3}{sup -} + H{sub 2}O + 2e{sup -} {yields} HCOO{sup -} + 2 HO{sup -}. In situ reflexion infrared spectroscopy studies, carried out in deuterated aqueous medium and by chrono-amperometry, have shown characteristic bands due to the hydrogeno-carbonate ion (weakly adsorbed) and to the formate produced, required for the understanding of the reactional mechanism. (O.M.)

  5. EVALUACIÓN DE LA PRODUCCIÓN DE ETANOL A PARTIR DE MELAZA CON CEPAS NATIVAS Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    FRANCISCO EMILIO ARGOTE V

    Full Text Available Este trabajo tuvo como objetivo principal evaluar la producción de etanol de nueve levaduras aisladas y caracterizadas en el Valle con un testigo de un ingenio brasilero. La evaluación de las variables como temperatura, oxígeno, dióxido de carbono y etanol durante el proceso de fermentación se realizó con la ayuda del equipo Ecochamber y la técnica HPLC para contrastar los valores encontrados. El diseño experimental correspondió al modelo unifactorial, y el tiempo de observación fue transversal en 48 horas, la unidad muestral fue de 600 mL de solución de melaza con una concentración de 16°Brix cuyo pH se ajustó a 4,5 con adición de acido cítrico. Los resultados se analizaron con el programa estadístico STATGRAPHICS 5.1, mediante ANOVA con un nivel de significancia de 0,05 y las diferencias con prueba de Tuckey. Como resultados relevantes se encontró que las variables temperatura y oxígeno no presentaron diferencias estadísticas con valores entre 24 a 32°C y 6,7 a 20% de manera respectiva, mientras que las cepas IC1, IP3, IP4, IP5 mostraron los mayores valores en producción de dióxido de carbono. En lo concerniente a la variable etanol, las cepas con mayor producción fueron T, IC1, IP3, IP4, IP6, IP5.

  6. Mechanical properties and total hydroxycinnamic derivative release of starch/glycerol/Melissa officinalis extract films

    Directory of Open Access Journals (Sweden)

    Letícia Mello Rechia

    2010-09-01

    Full Text Available The aim of this study was to investigate the mechanical properties of starch/glycerol/Melissa officinalis, a topical drug delivery system for labial herpes treatment. Four films were prepared with different concentrations of starch, glycerol, and Melissa officinalis extract. The results revealed that increasing the glycerol concentration in the film reduced elasticity modulus and tensile strength, exhibiting a plasticizing effect. The increase in free volume resulted in increased release of hydroxycinnamic derivatives expressed as rosmarinic acid.O objetivo deste trabalho foi estudar as propriedades mecânicas e o mecanismo de liberação de um sistema tópico de liberação prolongada para o tratamento do Herpes labial a partir de filmes de amido/glicerol/extrato de Melissa officinalis, planta com comprovada atividade antiviral. Foram obtidos quatro filmes poliméricos com diferentes concentrações de amido, glicerol e extrato de Melissa officinalis os quais foram caracterizados mecanicamente e determinado o perfil de liberação de derivados hidroxicinâmicos. Os resultados demonstraram que o aumento da concentração de glicerol no filme produz uma redução no módulo de elasticidade e na tensão de deformação como conseqüência do efeito plastificante. O aumento no volume livre do polímero resultou em aumento da liberação dos derivados hidroxicinâmicos expressos como ácido rosmarínico.

  7. Evaluation of a process for the removal of gases contained in geothermal steam through condensation and re-evaporation; Evaluacion de un proceso de remocion de gases contenidos en el vapor geotermico, por medio de la condensacion y de revaporacion

    Energy Technology Data Exchange (ETDEWEB)

    Angulo C, Raul; Lam Rea, Luis; Garmino, Hector; Jimenez, Humberto [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1985-12-31

    The Cerro Prieto I Geothermal Field, developed and operated by the Comision Federal de Electricidad (CFE), has currently an installed electric power generation capacity of 180 MW and is at a very advanced stage in the development of Cerro Prieto II and III, which will allow to raise the generation capacity to 620 MW. During the exploitation of a geothermal field, in producing steam with the purpose of generating electricity, brines and waste gases are obtained. The hydrogen sulfide exhaust to the environment implies pollution problems, for this reason processes have been developed for the oxidation of these gases downstream the turbogenerator either in the flow of separated gases in the steam condensation or in the condensate produced. The Instituto de Investigaciones Electricas (IIE) has collaborated with CFE in the evaluation of the environmental impact of this gas and in the development of the processes for its abatement. [Espanol] El campo geotermico de Cerro Prieto I, desarrollado y operado por la Comision Federal de Electricidad (CFE), actualmente tiene una capacidad instalada de generacion de energia electrica de 180 MW, y se encuentra en etapa muy avanzada, el desarrollo de Cerro Prieto II y III, lo que permitira incrementar la capacidad de generacion a 620 MW. Durante la explotacion de un campo geotermico, al producir vapor con el proposito de generar electricidad, se obtienen salmueras y gases de desecho. La descarga de acido sulfhidrico a la atmosfera implica problemas de contaminacion, por esta razon se han desarrollado procesos para la oxidacion de este gas aguas abajo de la turbina generadora, ya sea en la corriente de gases que se separan en la condensacion del vapor o en el condensado producido. El Instituto de Investigaciones Electricas (IIE) ha colaborado con la CFE en la evaluacion del impacto ambiental de este gas y en el desarrollo de sus procesos de abatimiento.

  8. Micro-organisms and divers exposure to radioactivity in spent fuel pools at nuclear power plants

    International Nuclear Information System (INIS)

    Muniz de A, D.; Silva, R.; Gomes N, C. A.

    2017-09-01

    Many nuclear power plants (NPPs) around the world are in the process of extending their lifespan from 40 to 60 years of operation. The NPP; Angra 1 (Brazil) has performed a thorough evaluation of its Life Extension Engineering project. In this context, the spent fuel pool (SFP) was one of the areas studied in order to demonstrate the plants integrity for a life extension. Micro-organisms growing on the liner of the fuel transfer channel (Ftc) and SFP can form a film of bacteria, which is highly resistant to radiation. This paper aims to compare the micro-organisms found in NPP Angra 1 with those reported to other NPPs and also relates their occurrence with the radiation levels at the sites. It also compares divers exposure to radioactivity during underwater activities in the SFP. Fourteen samples were collected on the surface of the liners of the Ftc, the SFP and the drains within the fuel building (FB) of Angra 1. For the identification of the micro-organisms, a metagenomics analysis was performed by random sequencing (Shotgun) and the use of Ion Torrent PGM Sequence r. Twelve micro-organisms phyla were identified; Acido-bacteria, Actino-bacteria, Bacteroidetes, Chlamydiae, Chlorobi, Chloroflexi, Cyano-bacteria, Deinococcus-Thermus, Firmicutes, Planctomycetes, Proteo-bacteria, and Verrucomicrobia as well as organisms not classified. In the SFP of Angra 1, the bacteria survived the exposure to a radiation of 0.416 Gy/h (high radiation). Deinococcus-thermus, bacteria identified in Angra 1, has resisted an exposure to 30,000 Gy/h in another plant. (Author)

  9. Catalytic mechanism of the dehydrogenation of ethylbenzene over Fe–Co/Mg(Al)O derived from hydrotalcites

    KAUST Repository

    Tope, Balkrishna B.

    2011-11-01

    Catalytic mechanism of ethylbenzene dehydrogenation over Fe-Co/Mg(Al)O derived from hydrotalcites has been studied based on the XAFS and XPS catalyst characterization and the FTIR measurements of adsorbed species. Fe-Co/Mg(Al)O showed synergy, whereas Fe-Ni/Mg(Al)O showed no synergy, in the dehydrogenation of ethylbenzene. Ni species were stably incorporated as Ni2+ in the regular sites in periclase and spinel structure in the Fe-Ni/Mg(Al)O. Contrarily, Co species exists as a mixture of Co3+/Co2+ in the Fe-Co/Mg(Al)O and was partially isolated from the regular sites in the structures with increasing the Co content. Co addition enhanced Lewis acidity of Fe3+ active sites by forming Fe3+-O-Co 3+/2+(1/1) bond, resulting in an increase in the activity. FTIR of ethylbenzene adsorbed on the Fe-Co/Mg(Al)O clearly showed formations of C-O bond and π-adsorbed aromatic ring. This suggests that ethylbenzene was strongly adsorbed on the Fe3+ acid sites via π-bonding and the dehydrogenation was initiated by α-H+ abstraction from ethyl group on Mg2+-O2- basic sites, followed by C-O-Mg bond formation. The α-H+ abstraction by O2-(-Mg 2+) was likely followed by β-H abstraction, leading to the formations of styrene and H2. Such catalytic mechanism by the Fe 3+ acid-O2-(-Mg2+) base couple and the Fe 3+/Fe2+ reduction-oxidation cycle was further assisted by Co3+/Co2+, leading to a good catalytic activity for the dehydrogenation of ethylbenzene. © 2011 Elsevier B.V. All rights reserved.

  10. Dosage of high COD industrial wastewaters as an external carbon source in the pre-denitrification step of activated sludge plants; Utilizzo di reflui industriali a elevato COD come fonte esterna di carbonio in pre-denitrificazione negli impianti a fanghi attivi

    Energy Technology Data Exchange (ETDEWEB)

    Bertanza, G.; Collivignarelli, C.; Pedrazzani, R. [Brescia Univ., Brescia (Italy). Facolta' di Ingegneria, Dipt. di Ingegneria Civile

    2001-04-01

    In pre-denitrification plants, the organic carbon shortage in the influent wastewater can inhibit the denitrification process. In this case, the dosage of organic substrates can be considered, when the F/M ratio in the nitrification stage is adequate. Beside commonly available substances (acetic acid, methanol etc.) industrial wastewaters can be dosed. This research was aimed to assess the feasibility of this alternative, by testing several industrial wastewaters in addition to real municipal wastewater. The experiment consisted in running a continuous-flow activated sludge pilot plant and in carrying out NUR (Nitrogen Uptake Rate) tests. The studied wastewaters derive from the food industry and, more precisely, from cocoa working and from the cold drink industry. Results were compared with two reference situations (dosage of sodium acetate and of an available organic solution). [Italian] Negli impianti con pre-denitrificazione, il processo di denitrificazione puo' essere inibito dalla carenza di carbonio organico nel liquame influente. Un rimedio (applicabile qualora il carico del fango in nitrificazione sia compatibile) consiste nel dosaggio di substrati carboniosi. Accanto alle soluzioni commercializzate (acido acetico, metanolo, ecc.) e' possibile dosare reflui industriali aventi caratteristiche adeguate. Nel presente studio si e' voluta verificare tale alternativa mediante una sperimentazione svolta su liquame fognario a cui sono stati aggiunti, di volta in volta, diversi substrati carboniosi. Le prove sono state effettuate sia in continuo (mediante l'impiego di un impianto pilota a fanghi attivi) sia in batch (test di NUR - Nitrogen Uptake Rate). I reflui studiati originano dall'industria alimentare, in particolare, dalla laovrazione del cacao e dalla produzione di bevande analcoliche. I risultati sono stati confrontati con due situazioni di riferimento (dosaggio di acetato di sodio e di una soluzione carboniosa disponibile in

  11. Desequilibrio hidroelectrolítico y ácido-base en la diarrea

    Directory of Open Access Journals (Sweden)

    Raúl L Riverón Corteguera

    2000-09-01

    Full Text Available Se realiza una revisión de los principios básicos del equilibrio hidromineral y acido-básico y se profundiza en los mecanismos homeostáticos más frecuentes en la edad pediátrica relacionados con las enfermedades diarreicas agudas. Se describe la clasificación y el manejo de la deshidratación con las sales de rehidratación oral (SRO (planes A y B y soluciones endovenosas (plan C, así como la fisiología y el tratamiento con bicarbonato de sodio en la acidosis metabólica. Se exponen los elementos relacionados con la regulación del sodio, del potasio y del equilibrio ácido-básico. Se hace referencia a la predisposición a la translocación bacteriana que presenta la hipovolemia mantenida más de 8 horas.A review of the basic principles of water-mineral and acid-base balance was made aand the most frequent homeostatic mechanisms in pediatric ages, which are related to acute diarrheal diseases were studied in depth. The classification and management of dehydration using oral rehydration salts (ORS (plans A and B and intravenous solutions (plan C as well as physiology and treatment of metabolic acidosis with sodium bicarbonate were described. The elements related to sodium and potassium control and acidd-base balance were set forth. Reference is mae to predisposition to bacterial translocation found in sustained hypovolemia for more than 8 hours.

  12. Inhibition of Neutral Red Photolysis with Different Antioxidants

    Directory of Open Access Journals (Sweden)

    Zlatan Rimpapa

    2007-02-01

    Full Text Available Neutral red is a dye the azine structure which has been used as an acido-base indicator and a dye in histochemistry. In 1960 Goldhaber introduced Neutral red into the medium of resorbing bone cultures to localize the osteoclast in the living cultures. Using time-lapse microcinematography in order to follow the osteoclasts, he reported excellent contrast could be obtained with Neutral red due to the avidity of osteoclasts for this dye. Unfortunately, however, the photodynamic effect resulting from subsequent exposure of these cultures to light precluded this approach, and again in 1963. it was observed that the death of the osteoclasts was probably due to a photodynamic effect related to the dye in the cell, the presence of oxygen and the frequent exposure of light by our time-lapse photography. VIS and UV irradiation induced photolysis of Neutral red, and from Neutral red cation produced with photons a Neutral red radical. This Neutral red radical can be inhibited with action of an antioxidant, such as melatonin, glutathione, ascorbic acid, E vitamin, etc. We developed an assay with Neutral redphotolysis which utilizes a VIS and UV irradiation technique for quantification the inhibition of photolysis with action of an antioxidant. In this method Neutral red acts double, as a free radical generator and as a photosensitizer.

  13. Microbiota de jamones de cerdo cocidos asociada al deterioro por abombamiento del empaque

    Directory of Open Access Journals (Sweden)

    Juliana Ossa

    2010-08-01

    Full Text Available Objetivo. Caracterizar la diversidad microbiana y calidad microbiológica e higiénico sanitaria de diferentes marcas de jamones de cerdo cocidos abombados y no abombados comprados en varios supermercados de Bogotá D.C. Materiales y métodos. Se analizaron 10 marcas diferentes de jamones de cerdo cocidos comprados en tres supermercados, refrigerados bajos las mismas condiciones del consumidor, durante 45 días. Se realizó los recuentos en placa de microorganismos de interés en la industria de alimentos y de inocuidad en las muestras con o sin distensión del empaque e identificación por pruebas bioquímicas y PCR para determinar la diversidad de la microbiota. Se aislaron cepas productoras de biopelículas provenientes de la superficie de una planta de alimentos de una de las marcas de los jamones investigadas. Resultados. Se identificaron un total de 139 cepas aisladas del producto terminado, de las cuales un 99% (137 cepas pertenecen al grupo de Bacterias Acido Lácticas (BAL, el 1% restante son levaduras. De las 31 cepas aisladas de las superficies en la zona de tajado, el 97% (30 cepas presentaron formación de biopelículas. Se determinó ausencia de patógenos tanto en el producto terminado como en las muestras de las superficies.Conclusiones. El deterioro causado por abombamiento del empaque fue asociado a la presencia de BAL, debido a que fueron encontradas en la zona de tajado y en el producto terminado, de este último únicamente se aislaron BAL, en mayor proporción cepas correspondientes al género de Lactobacillus sp.

  14. Synthesis and evaluation of Pt-alloys supported on MWCNTS as ethylene glycol-tolerant ORR cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, D.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Pedro Escobedo, Queretaro (Mexico); Alvarez-Contreras, L. [Centro de Investigacion en Materiales Avanzados S. C., Chihuahua, Chihuahua (Mexico); Fraire Luna, S.; Rodriguez Varela, F.J. [Cinvestav, Unidad Saltillo, Ramos Arizpe, Coahuila (Mexico)]. E-mail: javier.varela@cinvestav.edu.mx

    2009-09-15

    In this work, a Pt-Co/MWCNT alloy (atomic ratio 70:30) was synthesized and evaluated as oxygen reduction reaction (ORR) cathode for Direct Ethylene Glycol Fuel Cells (DEGFC) applications. The alloy showed good performance for the ORR in acid medium, while in the presence of 0.125M EG (C{sub 2}H{sub 6}O{sub 2}) the MWCNTs-supported electrocatalyst showed a very high selectivity for the cathodic reaction and a high degree of tolerance to the organic fuel, i.e., a very small shift in the onset potential for the ORR, Eonset, and no peak current densities associated to the oxidation of EG, a detrimental effect of organic fuels normally observed in the case of Pt-alone electrocatalysts. [Spanish] En este trabajo, se sintetizo y evaluo una aleacion Pt-Co/NTCMP (razon atomica 70/30) como catodo de reaccion de reduccion de oxigeno (RRO) para aplicaciones de celdas de combustible de glicol de etileno directo (CCGED). La aleacion mostro buen desempeno para la RRO en medio acido, en tanto que la presencia de 0.125M de GE (C{sub 2}H{sub 6}O{sub 2}) del electrocatalizador soportado por NTCMP mostro una muy alta selectividad para la reaccion catodica y un alto grado de tolerancia al combustible organico, es decir, un corrimiento muy pequeno del potencial de inicio para la RRO, Einicio, y no densidades de corriente asociadas a la oxidacion del GE, efecto perjudicial de los combustibles organicos que se observa en el caso del electrocatalizadores solo de Pt.

  15. Metabolism of methyl-branched iodo palmitic acids in cultured hepatocytes

    International Nuclear Information System (INIS)

    Thomas, G.; Pepin, D.; Loriette, C.; Chambaz, J.; Bereziat, G.; Vidal, M.; Apparu, M.; Coornaert, S.

    1989-01-01

    The metabolic fate of methyl-branched iodo fatty acids was studied in primary culture of rat hepatocytes. We compared 16-iodo-2-R,S-methyl palmitic acid (2-Me), which can be β oxidized, with 16-iodo-3-R,S-methyl palmitic acid (3-Me) which can be β oxidized only after an initial α oxydation and with 16-iodo-2,2-dimethyl palmitic acid (2,2-Me 2 ) and 16-iodo-3,3-dimethyl palmitic acid (3,3-Me 2 ) which cannot be β oxidized at all. The normal fate of natural fatty acids was given by comparative experiments with [1- 14 C] palmitic acid. Monomethyl-branched iodo fatty acids were taken up in the same range as palmitic acid but more than dimethyl-branched iodo fatty acids. After a 15-h incubation, acido-soluble products (ASP) accounted for 75% of the radioactivity taken up as 16-iodo-2-methyl palmitic acid, 50% as other methyl-branched iodo fatty acids and only 30% as palmitic acid. Cultured hepatocytes, labelled for 3 h with the various fatty acids and reincubated for 12 h without fatty acid, secreted large amounts of free dimethyl-branched iodo fatty acids as compared to the monomethyl ones and palmitic acid. Only hepatocytes prelabelled with 16-[ 125 I]iodo-2,2-dimethyl palmitic acid exhibited an appreciable secretion of labeled triglycerides, but at a lower rate than with [1- 14 C] palmitic acid. Conversely, the 16-iodo-monomethyl palmitic acids remained chiefly in hepatocyte triglycerides. Minute amounts of 16-iodo-methyl-branched palmitic acids were found in hepatocyte or secreted phospholipids as compared with palmitic acid. (orig.)

  16. New heterocycles having double characters; as antimicrobial and surface active agents.

    Directory of Open Access Journals (Sweden)

    El-Sayed, R.

    2004-12-01

    Full Text Available Fatty acids isothiocyanate (1 was used as a starting material to synthesize some important heterocycles such as triazoles, oxazoles, thiazoles, benzoxazoles and quinazolines by treating with different types of nucleophiles such as nitrogen nucleophiles, oxygen nucleophiles, and sulfur nucleophiles. The produced compounds were subjected to propylene oxide in different moles (n = 3, 5 and 7 to produce novel groups of nonionic compounds having the double function as antimicrobial and surface active agents which can be used in the manufacturing of drugs, cosmetics, pesticides or can be used as antibacterial and/or antifungal. The physical properties as surface and interfacial tension, cloud point, foaming height, wetting time, emulsification power and the critical micelle concentration (CMC were determined, antimicrobial and biodegradability were also determined.Isocianatos de acidos grasos se utilizaron como material de partida para la síntesis de importantes heterociclos tales como triazoles, oxazoles, thoazoles, benzoxazoles y quinazolinas mediante el tratamiento de los mismos con diferentes tipos de nucleofilos tales como nucleofilos nitrogenados, oxigenados, o azufrados. Los compuestos producidos se trataron con oxido de propileno a diferentes concentraciones molares (n = 3, 5 y 7 para producir nuevos grupos de compuestos no iónicos que tuvieran la doble función de ser compuestos antimicrobianos y agentes de superficie, que se pudieran usar en la fabricación de medicinas, cosméticos, pesticidas o como antibacterianos o antifúngicos. Se determinaron sus propiedades tales como tensión superficial e interfacial, punto de turbidez, altura de espuma, tiempo de mojado, poder de emulsificación y concentración micelar crítica (CMC, asi como sus propiedades antimicrobianas y de degradabilidad.

  17. Günther Anders’ Undiscovered Critical Theory of Technology in the Age of Big Data Capitalism

    Directory of Open Access Journals (Sweden)

    Christian Fuchs

    2017-06-01

    Full Text Available Günther Anders (1902-1992 was an Austrian philosopher, critical theorist, political activist, and a writer of poems, short stories and novels. His works on the critical theory of technology have remained rather undiscovered. His main work Die Antiquiertheit des Menschen (The Antiquatedness of the Human Being appeared in two volumes and has thus far not been published in English. This essay reviews key aspects of Anders’ works and uses them to critically assess big data capitalism. It first discusses Anders’ concept of the Promethean gap; the gap between what humans can produce with the help of technologies and the capacity of imagining the negative effects these technologies can have. The essay also engages with Anders’ analysis of commercial television and radio. Anders sees capitalism as having catastrophic potentials. He argues that Auschwitz and Hiroshima are two symbols of 20th-century catastrophism. The article discusses Anders’ letter to Klaus Eichmann, the son of Adolf Eichmann, who was in charge of the organisation of the displacement and deportation of Jews in the Third Reich. It furthermore analyses the exchange of letters between Anders and Claude Eatherly, the pilot of an aircraft that supported dropping the nuclear bomb “Little Boy” on Hiroshima. Finally, the paper engages with Anders’ critique of Martin Heidegger’s philosophy. In the age of the Internet and big data capitalism, Anders’ warnings about the potential negative effects of capitalist technologies and capitalism remain of crucial relevance and have taken on new qualities. Anders’ philosophy is an undiscovered critical theory of technology that allows us to critically understand power structures in the age of big data and social media. Günther Anders and Hannah Arendt. Source: posted on Flickr as CC by acido nucleio, https://www.flickr.com/photos/guntheranders/4248063814

  18. The Villas Carrousel PV-Wind Hybrid Project

    Energy Technology Data Exchange (ETDEWEB)

    Huacuz, Jorge M [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1998-12-31

    A pilot project was carried out to supply electrical services for an ecological hotel (eco-hotel), using solar and wind energy in Southeast Mexico. Fifteen small photovoltaic-wind hybrid systems were designed and built by researchers of the Electrical Research Institute of Mexico (IIE), as part of a cooperation agreement with the mexican company Carrousel Operadora Turistica, aimed at developing a technology package to supply electrical services to similar hotels sited in remote areas. Each hybrid system includes one wind generator of 500W nominal capacity, one PV panel ranging in power from 150W to 320 Watts peak, one lead-acid battery bank of 570 ampere-hour in capacity, and an electronic charge controller. This paper describes the systems and summarizes the results from the first twelve months of operation. [Espanol] Se llevo a cabo un proyecto piloto para el suministro de servicios electricos a un hotel ecologico (eco-hotel), utilizando energia solar y energia del viento en el Sudeste de Mexico. Investigadores del Instituto de Investigaciones Electricas de Mexico, disenaron y construyeron quince pequenos sistemas hibridos fotovoltaicos-viento, como parte de un acuerdo de cooperacion con la compania mexicana Carrousel Operadora Turistica, orientado al desarrollo de un paquete tecnologico para proporcionar servicios de energia electrica a hoteles similares ubicados en areas remotas. Cada sistema hibrido incluye un aero-generador con capacidad nominal de 500W un panel foto-voltaico con una potencia que varia entre los 150W y los 320W pico, una banco de baterias de plomo-acido de 570 amperes-hora de capacidad y un controlador electronico de carga. Este articulo describe los sistemas y presenta un resumen de los resultados de los primeros doce meses de operacion.

  19. Ionic composition and levels of acidity in rainfall in Maracaibo, Venezuela, between 1989 and 2001; Composicion ionica y niveles de acidez de las lluvias en Maracaibo, Venezuela, entre 1989 y 2001

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Ligbel; Morales, Jose; Velasquez, Harvi; Portillo, Dennis; Cano, Yulixis; Montilla, Brinolfo; Iriarte, Nelkis, Mesa, Johan [Universidad del Zulia, Maracaibo (Venezuela)]. E-mail: ligbels@hotmail.com

    2009-08-15

    de emision naturales y antropicas, se incorporan en las gotas de lluvia a traves de varios procesos fisicoquimicos durante los eventos de precipitacion. El conocimiento de la composicion quimica de las precipitaciones es critico para el entendimiento de la contaminacion regional y local y sus efectos sobre los ecosistemas. Entre las sustancias acidas o potencialmente acidas envueltas en la formacion de la lluvia acida, se puede senalar los compuestos de azufre, nitrogeno y cloro. Un factor importante en las caracteristicas acido-base de la lluvia es la emision de materiales alcalinos como carbonato de calcio, magnesio y amoniaco, que se encuentran generalmente como un vapor capaz de neutralizar los acidos sulfurico y nitrico. Los datos de la quimica de las lluvias, en este trabajo, provienen de varios sitios de la ciudad de Maracaibo, las muestras de agua de lluvia fueron recolectadas en tres periodos repartidos entre los anos 1989 y 2001, con equipos de muestreo manuales y automaticos. Para los diferentes analisis realizados se utilizaron un espectrometro de absorcion atomica modalidad llama, Perkin-Elmer 3110 y un cromatografo ionico con detector de conductividad, marca Dionex 2000i/SP. El pH-PPV en la lluvia de Maracaibo es 4.8, indicativo de una atmosfera ligeramente acida e influenciada por: SO{sub 4}{sup -2}, Cl{sup -} y NO{sub 3}{sup -} en 86 %. La especie neutralizante mas importante es el NH{sub 3}, aunque las concentraciones de Ca{sup +2} y Mg{sup +2} son aportes adicionales al proceso de neutralizacion atmosferica. El mayor flujo de depositacion humeda fue exhibido por: NH{sub 4}{sup +}, SO{sub 4}{sup -2}, Cl{sup -} y NO{sub 3}{sup -} con 67.5 %. Estadisticamente, se evidencio una alta correlacion entre SO4{sup *}, Cl{sup *} y NO{sub 3}{sup -} con el ion H{sup +} (p<0.05), ratificando su influencia en la acidez de las lluvias de Maracaibo. Se concluye que solo una pequena fraccion de los iones potencialmente acidos contribuyen a la acidez libre de las

  20. Use of a lactic acid plus lactoserum intimate liquid soap for external hygiene in the prevention of bacterial vaginosis recurrence after metronidazole oral treatment Uso do ácido láctico com lactoserum em sabonete líquido íntimo para higiene externa na prevenção da recorrência de vaginose bacteriana após tratamento oral com metronidazol

    Directory of Open Access Journals (Sweden)

    M. Valeria Bahamondes

    2011-08-01

    uso de acido láctico com lactoserum em sabonete líquido iniciado imediatamente após o tratamento com metronidazol oral e qualidade de vida das participantes. MÉTODOS: Um total de 123 mulheres com dianóstico de VB com ao menos três dos seguintes critérios: 1 leucorreia vaginal homogênea sem inflamação de vagina ou vulva; 2 pH vaginal ≥ 4,5; 3 teste positivo de Whiff; e 4 "clue cells" em mais de 20% das células epiteliais na vagina. O escore de Nugent ≥ 4 na bacterioscopia vaginal também foi usado. Após o diagnóstico de VB, metronidazol 500 mg oral foi ministrado durante 7 dias. Pacientes curados da VB foram instruídos a usar 7,5 a 10 mL de acido láctico com lactoserum em sabonete líquido uma vez ao dia para higiene da genitália externa. Três visitas de controle foram agendadas (30, 60 e 90 dias; ± 5 dias. Um questionário foi aplicado na forma de escala visual análoga (EVA em todas as visitas sobre: 1 nível de conforto na região genital; 2 mau odor na genitália; 3 conforto na relação sexual; 4 satisfação com higiene íntima; e 5 autoestima. RESULTADOS: Noventa e duas (74,8% mulheres iniciaram o uso de ácido láctico com lactoserum líquido na visita 1. Na visita 2, 3 e 4 foram 84, 62 e 42 mulheres para avaliação, respectivamente. A taxa de recorrência da VB foi 19,0%, 24,2% e 7,1%, respectivamente nas três visitas e candidíase vaginal foi observada em cinco mulheres. Qualidade de vida foi avaliada em 42 mulheres que completaram as quatro visitas agendadas e houve uma melhora significativa nos cinco domínios avaliados. CONCLUSÃO: O uso de acido láctico com lactoserum em sabonete líquido para higiene externa intima pode ser uma opção para a prevenção da recorrência de VB após tratamento e cura com metronidazol oral

  1. Monitoring system for individual cells in energy backing banks; Sistema para monitorizar las celdas individuales en bancos de respaldo de energia

    Energy Technology Data Exchange (ETDEWEB)

    Ortega S, Cesar A; Pacheco A, Maria Jojutla; Orozco V, Jaime A; Cristin V, Miguel A [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2004-07-01

    relatively smaller investment compared with the cost of a fault in the energy supply system. [Spanish] Las baterias plomo-acido (BPA) son ampliamente utilizadas en la industria para almacenar energia quimica y liberarla en forma de electricidad. Los fenomenos que ocurren en el interior de una BPA -durante sus ciclos de carga y descarga - afectan la vida util de la bateria a largo plazo. En este sentido, se han realizado diversas investigaciones alrededor del mundo; no obstante, dichos estudios han arrojado solo dos conclusiones: a) La seleccion de un algoritmo de carga adecuado puede extender la vida util de la bateria. b) Un monitoreo continuo del banco puede ayudar a estimar el estado de salud de las baterias y a detectar los elementos del banco que estan mas proximos a fallar. Una bateria plomo-acido esta formada por un conjunto de celdas plomo-acido conectadas en serie. A mayor numero de celdas, mayor el voltaje de la bateria. Las BPA que se utilizan para formar bancos de respaldo de energia son dispositivos sumamente delicados cuya vida util depende fuertemente de factores como: temperatura de operacion, regimen de descarga, regimen de carga. Las BPA se conectan, en serie, para elevar el voltaje, o bien, en paralelo, para elevar la corriente suministrada por el banco. Con una combinacion de arreglos serie-paralelo es posible lograr casi cualquier especificacion de voltaje y corriente. Por otro lado, la operacion confiable de un arreglo de celdas requiere que todos los elementos de este funcionen correctamente. Si una celda falla en un arreglo serie, el resto deja de funcionar, lo que ocasiona costos de mantenimiento ademas de reducir la confiabilidad del sistema de respaldo. Para incrementar la confiabilidad de los arreglos de celdas Pb-A, es necesario un monitoreo individual y continuo de las celdas. Ello permite determinar cuales son las que tienen mayor probabilidad de falla y, entonces, poder reemplazarlas. Entre los principales beneficios de un sistema de monitoreo

  2. Análisis de correlación y heredabilidad en el mejoramiento genético del camu-camu

    Directory of Open Access Journals (Sweden)

    Mario Pinedo Panduro

    2012-01-01

    Full Text Available En Perú y Brasil se han efectuado entre los años 2002 y 2011, estudios de correlación y heredabilidad en la búsqueda de herramientas para el mejoramiento genético del camu-camu. Se pretende con este trabajo, sistematizar la información lograda que apunte a la consolidación de cr iterios para la selección de plantas superiores. Se estudiaron colecciones básicas, comparativos de clones y de progenies existentes en el INIA, IIAP e INPA. La longitud de pecíolo (LP, presenta una heredabilidad media (en el sentido amplio de h 2 g= 0.4 2 e índices de correlación de r 2 =0.37 con rendimiento de fruta y r 2 =0.54 con peso de fruta El Número de Ramas Basales (NRB también muestra niveles de heredabilidad media (en el sentido estricto: h 2 a=0.45 y h 2 g=0.33 en el sentido amplio. NRB a su vez c orrelaciona significativamente con rendimiento de fruta (RF (r 2 =0.43, peso de fruta (PF (r 2 =0.38 y con acido ascórbico (AA (r 2 = - 0.30. Los valores de pH y sólidos solubles (grados Brix de la pulpa, presentaron una correlación alta con AA (r 2 =0.85 y r 2 =0.94, respectivamente. A la luz de la información de correlación y heredabilidad, subrayamos que los parámetros “número de ramas basales”, “longitud de peciolo” y “peso de frutos” además de presentar una correlación relativamente alta con “rendimient o de fruta” tienen también un nivel intermedio de heredabilidad, lo que las cataloga como herramientas de importancia para la selección de plantas superiores de camu-camu.

  3. Physico-Chemical Properties of MgGa Mixed Oxides and Reconstructed Layered Double Hydroxides and Their Performance in Aldol Condensation of Furfural and Acetone

    Directory of Open Access Journals (Sweden)

    Oleg Kikhtyanin

    2018-05-01

    Full Text Available MgGa layered double hydroxides (Mg/Ga = 2–4 were synthesized and used for the preparation of MgGa mixed oxides and reconstructed hydrotalcites. The properties of the prepared materials were examined by physico-chemical methods (XRD, TGA, NH3-TPD, CO2-TPD, SEM, and DRIFT and tested in aldol condensation of furfural and acetone. The as-prepared phase-pure MgGa samples possessed hydrotalcite structure, and their calcination resulted in mixed oxides with MgO structure with a small admixture phase characterized by a reflection at 2θ ≈ 36.0°. The interaction of MgGa mixed oxides with pure water resulted in reconstruction of the HTC structure already after 15 s of the rehydration with maximum crystallinity achieved after 60 s. TGA-MS experiments proved a substantial decrease in carbonates in all rehydrated samples compared with their as-prepared counterparts. This allowed suggesting presence of interlayer hydroxyls in the samples. Acido-basic properties of MgGa mixed oxides determined by TPD technique did not correlate with Mg/Ga ratio which was explained by the specific distribution of Ga atoms on the external surface of the samples. CO2-TPD method was also used to evaluate the basic properties of the reconstructed MgGa samples. In these experiments, an intensive peak at T = 450°C on CO2-TPD curve was attributed to the decomposition of carbonates newly formed by CO2 interaction with interlayer carbonates rather than to CO2 desorption from basic sites. Accordingly, CO2-TPD method quantitatively characterized the interlayer hydroxyls only indirectly. Furfural conversion on reconstructed MgGa materials was much larger compared with MgGa mixed oxides confirming that Brønsted basic sites in MgGa catalysts, like MgAl catalysts, were active in the reaction. Mg/Ga ratio in mixed oxides influenced product selectivity which was explained by the difference in textural properties of the samples. In contrast, Mg/Ga ratio in reconstructed catalysts had

  4. Prise en charge diagnostique et thérapeutique de la tuberculose ganglionnaire en Tunisie

    Science.gov (United States)

    Ben Brahim, Hajer; Kooli, Ikbel; Aouam, Abir; Toumi, Adnene; Loussaief, Chawki; Koubaa, Jamel; Chakroun, Mohamed

    2014-01-01

    La tuberculose ganglionnaire est la localisation extra-pulmonaire la plus fréquente de la tuberculose. Nous nous proposons dans ce travail d’étudier les modalités diagnostiques, thérapeutiques et évolutives de cette localisation. Il s'agit d'une étude rétrospective portant sur 100 cas de tuberculose ganglionnaire. L’âge moyen était de 35 ± 15 ans (15-85 ans). Aucun malade n’était VIH positif. L'aire cervicale était la plus touchée (93 cas). L'intradermo-réaction à la tuberculine était positive dans 76/91 cas (83,5%). L'examen bactériologique des prélèvements au niveau des ganglions atteints avait mis en évidence des bacilles acido-alcoolo-résistants à l'examen direct dans 2/31 cas (6,4%) et la culture avait isolé Mycobacteruim tuberculosis dans 1/31 cas (3,2%). La cytoponction ganglionnaire (FNAC) était évocatrice de tuberculose dans 35/42 cas (83,3%). La biopsie ganglionnaire était réalisée dans 69 cas et avait permis de retenir le diagnostic de tuberculose dans tous les cas. La FNAC, comparativement à la biopsie, avait permis de raccourcir significativement le délai de la prise en charge (15,1 vs 22,8 jours; p=0,001) et la durée d'hospitalisation (17,3 vs 24,6; p=0,004). La durée moyenne du traitement antituberculeux était de 9,8 ± 4,6 mois (7 à 44 mois). Le traitement chirurgical initial avait raccourci significativement la durée du traitement médical. Il n'avait pas d'impact sur le taux de guérison. Nous avons noté 10 cas de réponse paradoxale aux antituberculeux, quatre cas de résistance clinique et une rechute dans deux cas. La tuberculose ganglionnaire pose un problème diagnostique et thérapeutique. La microbiologie est d'un faible apport. La FNAC est un moyen diagnostique très utiles dans les pays endémiques et à faibles ressources. Un traitement médical seul permet d’éviter les inconvénients de la chirurgie. PMID:25829976

  5. Deficiência hídrica e aplicação de ABA nas trocas gasosas e no acúmulo de flavonoides em calêndula (Calendula officinalis L. = Water deficit and ABA application on leaf gas exchange and flavonoid content in marigold (Calendula officinalis L..

    Directory of Open Access Journals (Sweden)

    Ana Cláudia Pacheco

    2011-04-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos da deficiencia hidrica e aplicacao de acido abscisico (ABA sobre aspectos fisiologicos e teor de flavonoides em plantas de calendula. Oexperimento foi instalado em condicoes de casa-de-vegetacao com plantas envasadas. No inicio do florescimento de plantas de calendula, foram aplicados quatro intervalos de suspensao da irrigacao (irrigacao diaria; tres; seis e nove dias sem irrigar, acompanhados por tres doses de ABA (0, 10 e 100 ƒÊM. Avaliou-se o conteudo relativo de agua na folha (CRA e as trocas gasosas, utilizando-se um analisador portatil por infravermelho (A: fotossintese liquida, gs: condutancia estomatica, E: transpiracao, Ci: concentracao intercelular de CO2 e EUA: eficiencia de uso daagua. Aos nove dias sem irrigacao ocorreram reducoes significativas em todas as variaveis de trocas gasosas analisadas, independente da aplicacao de ABA. Concluiu-se que o efeito principal do ABA foi o de causar diminuicao na gs, a qual foi acompanhada de reducao em A somente quando as plantas estavam desidratadas. As intensidades de deficiencia hidrica testadas nao causaram interferencia no acumulo de flavonoides nas inflorescencias. Entretanto, o ABA restringiu a biossintese de flavonoides, tanto nas plantas-controle como nas plantas submetidas a deficiencia hidrica.The goal of this study was to evaluate the effects of water deficit and abscisic acid (ABA application on physiological parameters and flavonoid production in marigold plant. The experiment was performed under nursery conditions with potted plants. It was tested water deficit by withholding water (control . diary irrigation, 3, 6 and9 days without irrigation followed by 3 ABA concentrations (0, 10 e 100 ƒÊM applied in the beginning of blooming. It was evaluated the relative water content and the leaf gas exchange using a portable infrared gas analyzer (A: net photosynthesis, gs: stomatal conductance, E: transpiration, Ci: CO2 intercellular

  6. APLICACIÓN DE LA TECNICA DE IV GAMA PARA LA ELABORACIÓN DE ENSALADAS EVALUATION OF IV GAMA TECHNIQUE TO PREPARE VEGETABLE SALADS

    Directory of Open Access Journals (Sweden)

    Auris Damely García Méndez

    2008-12-01

    Full Text Available El propósito de la aplicación de la técnica de IV Gama en la elaboración de ensaladas listas para el consumo fresco, esta dirigido al control del deterioro en lechuga americana (Lactuca sativa, zanahoria (Daucus carota L., radicchio (Cichorium intybus L. y escarola (Cichorium endivia L., destinadas a preparar ensaladas tipo “Mediterránea y Cheff”. La metodología permitió seleccionar y evaluar la técnica de IV Gama, así como las buenas prácticas de manufactura para extender la vida comercial de las ensaladas y garantizar la seguridad alimentaria para la población potencialmente consumidora. La aplicación combinada de soluciones de cloruro de calcio al 1%, acido cítrico a 0,1% y oxido de magnesio al 0,5% contribuyo a mantener la calidad de las ensaladas por un período de 16 días bajo refrigeración a 5 + 1 °C y 95 + 5% HR. En conclusión las técnicas ensayadas, posibilitaron extender el valor comercial de estos productos.The purpose of applying the fresh-cut technique in preparing vegetable salads ready for fresh consumption, was aimed to control the damage American lettuce (Lactuca sativa; carrot (Daucus carota L; Radicchio (Cichorium intybus L and endive (Cichorium endivia L.“ Mediterranean and Cheff” style salads were prepared for evaluation. The methodology allowed selecting and evaluating fresh-cut technique as well as good manufacturing practices, to extend the commercial life, and guarantee alimentary food safety to people. Use of 1% calcium chloride; 0.1% citric acid and 0.5% magnesium oxide solutions; allowed to maintain the quality of the salads for a period of 16 up to days, under refrigeration at 5± 1ºC and 95 ± 5 % RH. Finally the assays techniques let to extend the commercial value of these vegetables.

  7. Influência da embalagem e estocagem no conteúdo de betacaroteno e ácido ascórbico em suco de manga “Ubá” industrializado = Influence of package and storage on the content of beta-carotene and ascorbic acid in industrialized “Ubá” mango juice

    Directory of Open Access Journals (Sweden)

    Daniela da Silva Oliveira

    2010-07-01

    Full Text Available Este trabalho investigou o conteudo e avaliou a estabilidade de doisantioxidantes naturais - β-caroteno e acido ascorbico (AA - em suco de manga "Uba" industrializado e armazenado em diferentes tempos de estocagem e correlacionou as recomendacoes de vitaminas A e C com o teor encontrado nos sucos. O β-caroteno e o AA foram analisados nos sucos comercializados em embalagem tetra pak, em cinco tempos de estocagem (1 a 5 meses e em embalagem de vidro, em tres tempos de estocagem (apos 3, 4 e 5 meses de armazenamento. A analise foi realizada por Cromatografia Liquida de Alta Eficiencia (CLAE. Nao foram detectadas diferencas estatisticamente significativas (α = 5% entre os diferentes tempos de estocagem, para ambos os componentes analisados, tanto em embalagens tetra pak quanto em embalagens de vidro. Alem disso, nao foram observadas diferencas significativas entre o conteudo de β-caroteno dos sucos comercializados nas duas embalagens. No entanto, houve diferenca significativa no teor de AA entre as diferentes embalagens, e a embalagem de vidro apresentou maior teor em relacao a embalagem tetrapak. Assim, as perdas ocasionadas especialmente pela permeabilidade da embalagem ao oxigenio deveriam ser alvo de atencao das industrias de alimentos.This work investigated the content and stability of two natural antioxidants . β-carotene and ascorbic acid (AA - in mango juice industrialized and stored during different storage times, correlating the recommendations of vitamins A and C with the content found in the juice. β-carotene and AA were analyzed in juice sold in tetra pak packaging, during five storage times (1 to 5months and in glass containers, during three storage times (after 3, 4 and 5 months of storage. The analysis was carried out using High Performance Liquid Chromatography (HPLC. No statically differences (α = 5 % were found between the different times of storage for both compounds analyzed, both in tetra pak package and glass container

  8. Avaliação da atividade antioxidante e alelopática do extrato etanólico e frações das cascas do caule de Zanthoxylum rhoifolium Lam., Rutaceae

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    Joelle de Melo Turnes

    2014-08-01

    Full Text Available Este trabalho teve como objetivo o estudo das atividades antioxidante e alelopática das cascas do caule de Zanthoxylum rhoifolium Lam., Rutaceae, de modo a conduzir à descoberta de substâncias biologicamente ativas. O material vegetal foi submetido à extração etanólica e este extrato foi fracionado obtendo as frações (hexano, clorofórmio, acetato de etila e hidroalcoólica. Para a avaliação da atividade antioxidante, empregaramse os métodos de redução do complexo fosfomolibdênio, de redução do radical DPPH e das substâncias reativas ao acido tiobarbitúrico (TBARS. Quanto à alelopatia, as amostras foram testadas em quatro concentrações sobre a germinação e o desenvolvimento de radícula e hipocótilo das sementes de Lactuca sativa. As amostras evidenciaram atividade antioxidante significativa frente ao método de redução do complexo fosfomolibdênio quando comparada à rutina, e do TBARS quando comparado ao BHT, assim como a atividade alelopática, uma vez que estimularam tanto a germinação como o crescimento das sementes. A fração clorofórmica e acetato de etila demonstraram melhor potencial antioxidante com 204,17% e 127,11% em relação à rutina no método de formação do complexo fosfomolibdênio, e o extrato bruto e a fração hexano com 64,2% e 60,9%, em relação ao BHT, no método TBARS. No ensaio alelopático, destaca-se a fração clorofórmica, pois foi a única amostra que estimulou o crescimento do hipocótilo e radícula na maioria das concentrações, variando de 41 a 144%, e a fração acetato de etila que apresentou a maior porcentagem de estímulo nesse bioensaio, demonstrando estímulo de 274% do crescimento do hipocótilo. Este é o primeiro trabalho que demonstra a atividade antioxidante e alelopática de Z. rhoifolium.

  9. Physicochemical and microbiological study of “shmen”, a traditional butter made from camel milk in the Sahara (Algeria: isolation and identification of lactic acid bacteria and yeasts

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    Mourad, Kacem

    2006-06-01

    Full Text Available Microorganisms (aerobic bacteria, coliforms, lactic acid bacteria, psychrotrophs, lipolytic bacteria and yeasts were isolated from 20 samples of shmen, a traditional clarified butter made from sour camel milk in the Algerian Sahara. The values of pH, titratable acidity, NaCl, total solid, moisture, and fat content ranged from : 3.11-4.97, 0.19-0.36%, 1.04-2.15%, 64.03-65.11%, 34.40-34.99%, and 49.90-56% respectively. A total of 181 isolates of lactic acid bacteria were identified as Lactobacillus plantarum (40 strains, Lactobacillus delbrueckii ssp. bulgaricus (35 strains, Lactococcus lactis ssp. lactis biovar diacetylacti (22 strains, Lactococcus lactis ssp. cremoris (18 strains, Lactobacillus paracasei ssp. paracasei (10 strains, Leuconostoc pseudomesenteroides (9 strains and Leuconostoc gelidum (12 strains Enterococcus faecium (35 strains. Yeasts were isolated from all samples (55 isolates. Of these, 40 were identified as Saccharomyces cerevisiae and 15 isolates were identified as Saccharomyces sp.Se aislaron los microorganismos (bacterias aeróbicas, coliformes, bacterias acido lácticas, bacterias lipolíticas y levaduras de 20 muestras de “shmen”, una matequilla tradicional del Sahara argelino hecha a partir de leche de camella. Los valores de pH, acidez, libre, Nacl, solidos totales, humedad y grasa oscilaron entre 3,11-4,97, 0,19-0,36%, 1.04-2,15%, 64,03-65,11%, 34,40-34,99% y 49,90-56,00%, respectivamente. Entre los 181 cultivos puros de bacterias lácticas se identificaron Lactobacillus plantarum (40 cepas, Lactobacillus delbrueckii ssp. bulgaricus (35 cepas, Lactococcus lactis ssp. lactis biovar diacetylacti (22 cepas, Lactococcus lactis ssp. cremoris (18 cepas, Lactobacillus paracasei ssp. paracasei (10 cepas, Leuconostoc pseudomesenteroides (9 cepas and Leuconostoc gelidum (12cepas Enterococcus faecium (35 cepas. Asimismo, se detectaron levaduras en todas las muestras (55 cultivos puros. De estos, 40 se identificaron como

  10. Cinética de fermentación y acción antimicrobiana de Weissella confusa contra Staphylococcus aureus y Streptococcus agalactiae

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    Liliana Serna Cock

    2010-01-01

    Full Text Available Se evaluaron las cinéticas de producción de biomasa, producción de ácido láctico, consumo de sustrato y actividad antimicrobiana de Weissella confusa, una bacteria acido láctica con actividad antimicrobiana frente a Streptococcus agalactiae y Staphylococcus aureus, microorganismos productores de mastitis bovina. Las fermentaciones se llevaron a cabo anaeróbicamente en discontinuo utilizando como sustratos, sustrato comercial (SC, leche suplementada con extracto levadura (LEL y leche suplementada con extracto de levadura y glucosa (LELG y se compararon los parámetros cinéticos. La mayor inhibición de los patógenos, la mayor producción de ácido láctico y el mayor rendimiento de biomasa se presentó en sustrato LELG. En éste último sustrato al cabo de la cuarta hora de fermentación, se presentó un diámetro de inhibición de 36,33 mm para Staphylococcus aureus y a la octava hora de fermentación 39 mm de diámetro para Streptococcus agalactiae; la producción máxima de ácido láctico fue 13,12 gL-1 (a las 48 h y la máxima concentración de biomasa fue 3,07 gL-1 (a las 48 h. Estos resultados fueron superiores a los obtenidos en SC donde, para el mismo tiempo de fermentación, se obtuvieron 24,38 mm para Staphylococcus aureus y 30,58 mm de diámetro de inhibición para Streptococcus agalactiae; la mayor producción de ácido láctico fue 11,6 gL-1 (a las 12 h y la mayor concentración de biomasa fue 1,18 gL-1 (a las 24 h. Los resultados sugieren que el LELG puede convertirse en una alternativa a bajo costo para la producción de Weissella confusa, microorganismo con gran potencial para el control y el tratamiento de mastitis bovina.

  11. ENRIQUECIMIENTO DE HUEVOS CON ÁCIDOS GRASOS OMEGA-3 MEDIANTE LA SUPLEMENTACIÓN CON SEMILLA DE LINO (Linum usitatissimum EN LA DIETA

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    Gonzalo Díaz

    2009-04-01

    Full Text Available Objetivo. Enriquecer los huevos de gallina con ácidos grasos omega-3 (n-3 mediante la inclusión de semillas de lino en la dieta. Materiales y métodos. La dieta de las aves fue formulada con niveles de 0 (L0, 10 (L10, 15 (L15 y 20% (L20 de linaza. Se determinó la composición de ácidos grasos por cromatografía de gases y se evaluó la producción y calidad del huevo. Resultados. El porcentaje de producción de huevo fue superior en los grupos L0 y L15 (p<0.05 con 93,0 y 91,5% de producción comparada con 86,0 % en los grupos L10 y L20. La mejor conversión de alimento se presentó también en los grupos L0 y L15. Con la inclusión de semilla de lino, se incrementó el contenido de ácidos grasos n-3 desde 3,0 % en el grupo L0 hasta 12,6 % en el grupo L20, siendo los ácidos grasos n-3 á-linolénico (C18:3, n-3 y docosahexahenóico (DHA, C22:6, n-3 los hallados en mayor concentración. Con la inclusión de linaza en la dieta de las gallinas ponedoras se redujo el contenido de acido linoleico (C18:2n-6, lo cual resultó en una disminución en la relación n-6: n-3. Conclusiones. Con base en la evaluación económica se concluye que es posible enriquecer la yema de huevo de gallina hasta con un 10,1 % de ácidos grasos n-3 mediante la inclusión de un 15 % de linaza en la dieta de las gallinas, sin embargo, esto representó un sobrecosto de producción del 12%.

  12. Nutritional changes in powdered red pepper upon in vitro infection of Aspergillus flavus Alterações nutricionais em pimenta vermelha em pó após infecção in vitro com Aspergillus flavus

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    Smita Tripathi

    2009-03-01

    Full Text Available Quantitative losses in various biochemical constituents like capsaicin, carotenes, ascorbic acid, polyphenols, mineral matter, sugars (soluble and insoluble, protein and fat were estimated after the successful growth of Aspergillus flavus for 30 days on powdered red pepper. The fungal biomass was measured by ergosterol content and Aflatoxin B1 by HPLC. Amongst the various nutritional constituents evaluated for nutritional losses and changes the highest nutritional loss was reported in total carotenoids (88.55% followed by total sugars (85.5%. The protein content of the infected sample increased from 18.01% to 23%. The nutritional profile of chilli powder (Capsicum annum var. sannam L. shows highest share of total soluble sugars (32.89% and fiber content (21.05%, followed by protein (18.01% and fat (13.32% making it an ideal solid - substrate for mould growth. At the end of incubation the fungal biomass was 192. 25 mg / 100 gram powder, total plate count 17.5 X 10 4 CFU/g and Aflatoxin B1 content was 30.06 µg / kg.Foram avaliadas as perdas de vários constituintes bioquímicos como capsaicina, carotenos, acido ascórbico, polifenóis, matéria orgânica, açucares (solúveis e insolúveis, proteína e gordura em pimenta vermelha em pó após a multiplicação de Aspergillus flavus por 30 dias. A biomassa fúngica foi mensurada pelo conteúdo de ergosterol e aflatoxina por HPLC. Entre os vários constituintes avaliados, a maior perda foi a de carotenóides totais (88,55%, seguido de açucares totais (85,5%. O conteúdo protéico da amostra infectada aumentou de 18,01% para 23%. O perfil nutricional da pimenta em pó (Capsicum annum var. sannam L. indica alto teor de açucares totais (32,89% e fibras (21,05%, seguido de proteína (18,01% e gordura (13,32%, tornando-a um substrato ideal para crescimento de fungos. Ao final dos 30 dias, a biomassa fúngica foi 192,25 mg/100g, a contagem total em placas foi 17,5 x 10(4 CFU/g e o conteúdo de

  13. The Dow Ethyl Bromide Process: An Industrial Application of Radiation Chemistry; Application industrielle de la radiochimie a la production de bromure d'ethyle; Promyshlennoe primenenie radiatsionnoj khimii dlya proizvodstva ehtilbromida (metod dau); Aplicacion industrial de los efectos quimicos de las radiaciones a la produccion de bromuro de etilo

    Energy Technology Data Exchange (ETDEWEB)

    Harmer, D. E.; Beale, J. S.; Pumpelly, C. T.; Wilkinson, B. W. [Dow Chemical Company, Midland, MI (United States)

    1963-11-15

    Beginning in March 1963, the Dow Chemical Company started manufacturing its entire production of the organic chemical, ethyl bromide, by a process in which the addition of hydrogen bromide to ethylene is induced by a source of gamma radiation. This process constitutes a competitive, commercial use of 1800 curies of cobalt-60 as the reaction initiator. Drawings and photographs of this production plant are presented, and radiation yields are given. Experiences gained during the actual start-up of this process unit are discussed. (author) [French] Depuis mars 1963, la societe Dow Chemical produit la totalite de son bromure d'ethyle en utilisant un piocede dans lequel la combinaison de l'acide bronhydrique et de l'ethylene est amorcee par une source de rayons gamma. Il s'agit la d'une utilisation commerciale et rentable du cobalt-60 (1800 c) comme initiateur d'une reaction. L'auteur presente des plans ainsi que des photographies de l'usine et etudie le rendement de l'operation. Il donne enfin les resultats de l'experience acquise depuis le demarrage de l'installation de production. (author) [Spanish] Desde marzo de 1963 la Dow Chemical Company produce todo su bromuro de etilo por un metodo en el que la adicion de acido bromhfdrico al etileno es inducida por una fuente de rayos gamma. Este proceso constituye una aplicacion comercial rentable del cobalto-60 (1800 c), como iniciador del proceso. Se presentan planos y fotografias de la planta y se examinan los rendimientos radiatorios. Se tratan asimismo los aspectos relativos a la experiencia adquirida durante la puesta en servicio de la planta. (author) [Russian] V marte 1963 goda firma ''Dau kemikl kompani'' tselikom pereshla na proizvodstvo ehtilbromida: teper' prisoedinenie bromistogo vodoroda k ehtilenu proiskhodit pod dejstviem gamma-oblucheniya. Ehtot protsess predstavlyaet soboj primer promyshlenno vygodnogo, rentabel'nogo primeneniya Co{sup 60} s aktivnost'yu 800 kyuri - vozbuditelya reaktsii. Predstavleny

  14. Cyanic acid, Phytic acid, total tannin and aflatoxin contents of a Brazilian (Natal multimistura preparation Conteúdos de ácido cianídrico, ácido fítico, tanino total e aflatoxina em uma preparação brasileira (Natal de multimistura

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    Francisca Sônia CÂMARA

    2001-04-01

    Full Text Available The utilization of a "multimistura" as food supplement, in nutritional improvement programs for the low-income population in Brazil, represents a low-cost and easy-to-use food preparation alternative, presentig reasonable nutritive value and satisfying local taste preferences. This is based on the fact that the "multimistura" is made up of non-conventional ingredients/foods and of agroindustrial by-products, rich in different nutrients. This paper was designed to determine some toxic and/or antinutritional factors of a "Multimistura" utilized as food supplement in institutional programs to prevent malnutrition by the Department of Welfare and Social Affairs of the City of Natal, RN. The product studied had the following formulation: 30% of wheat bran; 30% of wheat flour; 30% of corn meal; 3% of powder from cassava leaves; 4% of pumpkin seeds powder; and 3% of eggshell powder. The analysis of the main toxic and/or antinutritional factors showed very low concentrations of phytates and tannins and no detectable levels of aflatoxin and cyanic acid.O uso da "multimistura" como suplemento alimentar, em programas de intervenção nutricional para populações brasileiras carentes, vem se apresentando como uma alternativa alimentar de valor nutritivo razoável, baixo custo, preparo rápido e paladar regionalizado. Isto resulta do fato desta ser constituída principalmente de alimentos não convencionais e/ou subprodutos agro-industriais ricos em diferentes nutrientes. Este trabalho teve como objetivo dosar alguns fatores tóxicos e/ou antinutricionais de uma "multimistura" utilizada como suplemento alimentar em programas institucionais no combate à desnutrição da Secretaria Municipal de Promoção Social da cidade de Natal. O produto analisado tinha a seguinte formulação: 30% de farelo de trigo; 30% de farinha de trigo; 30% de fubá de milho; 3% de pó de folha de mandioca; 4% de pó de semente de jerimum; 3% de pó de casca de ovo. As an

  15. Biomarkers for environmental and occupational exposure to aromatic mutagens and carcinogens from emissions of oil shale petrochemistry. Report of the EC PECO programme, project CIPA-CT92-3016

    Energy Technology Data Exchange (ETDEWEB)

    Carere, A.; Crebelli, R. [eds.] [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Tossicologia Comparata ed Ecotossicologia

    1998-03-01

    di ricerca, coordinato dall`Istituto Superiore di Sanita`, sui biomarcatori di esposizione a cancerogeni aromatici nella lavorazione degli scisti bituminosi. Le ricerche condotte hanno dimostrato la possibilita` di valutare l`esposizione individuale a livelli relativamente bassi di policicli aromatici e benzene attraverso la determinazione dell`idrossipirene ed acido trans, trans-mucotico urinari, rispettivamente, e del benzene ematico. E` stato sviluppato anche un nuovo, promettente metodo per la determinazione del benzene addotto alla emoglobina, ed ulteriormente raffinata e validata la metodologia per l`analisi di addotti sul DNA basata sulla post-marcatura con {sup 32}P. I risultati dlele analisi citogenetiche condotte hanno messo in luce la maggiore sensibilita` delle nuove tecniche molecolari basate sulla ibridazione in situ rispetto ai metodi convenzionali, prospettandone il possibile ruolo nella sorveglianza della esposizione a cancerogeni.

  16. Nitrous oxides reduction pathways induced during nitrified leachate recirculation in bioreactor landfill; Voies de reduction des oxydes d'azote lors de leur injection dans un massif de dechets menagers et assimiles: contribution a l'etude de la recirculation de lixiviat nitrifie dans une installation de stockage de dechets menagers et assimiles bioactive

    Energy Technology Data Exchange (ETDEWEB)

    Vigneron, V

    2005-12-15

    Nitrified leachate recirculation in bioreactor landfill has been proposed to avoid ammonium accumulation. We worked on the identification of nitrous oxides reduction pathways induced when nitrified leachate is recirculated during waste degradation. Batch reactors (1.1 liter, 40 g of reconstituted Municipal Solid Waste, MSW) were operated at 35 deg C and saturated with leachate. Injections of 250 mg N-NO{sub x}.10{sup -1} were performed during different phases of waste biodegradation. Nitrate reduction during acido-genic and active methanogenic phases, with an easily available carbon source in leachate, was mainly attributed to heterotrophic denitrification. However, H{sub 2}S concentration up to 0.7 % in the biogas (corresponding to 0.5 mmol of free H{sub 2}S per liter of leachate) led to prevalent DNRA (Dissimilatory Nitrate Reduction to Ammonium) over denitrification. This reaction hindered the release of nitrogen outside of the system. This observation was confirmed with experiments performed with {sup 15}N enriched nitrate. During late methanogenic phase, without any available carbon source in leachate, nitrate was reduced by autotrophic denitrification with sulfide as an electron donor. No free metal was detected in the leachate. N{sub 2}O transient accumulation was detected during both DNRA and autotrophic denitrification. A second set of experiments was conducted in a MSW pilot scale column (0.2 m{sup 3}, 80 kg of reconstituted waste) in methanogenic phase. 113 % and 203 % of nitrate were converted into N{sub 2} when a synthetic KNO{sub 3} solution (280 mg N.day{sup -1} during 77 days) or nitrified leachate (61 mg N.day{sup -1} during 54 days) were respectively injected into the system. The downward movement of a denitrification front passing through the waste mass was followed using 3 redox probes inserted at different levels of the pilot. Even if N{sub 2}O was never detected, a small production of this gas could not be totally excluded. It was established

  17. Actividad antioxidante de extractos de diez basidiomicetos comestibles en Guatemala

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    Karen Belloso

    2015-11-01

    Full Text Available Los antioxidantes son esenciales en el cuerpo humano para prevenir el daño oxidativo. Estas substancias pueden obtenerse de diversas fuentes como frutas, plantas y hongos. En Guatemala, diversas especies de hongos comestibles son comercializadas y consumidas, sin embargo su actividad antioxidante no ha sido documentada en el país. El objetivo de este estudio fue determinar la actividad antioxidante de extractos acuosos y etanólicos obtenidos de diez especies de basidiomicetos comestibles (Agaricus aff. bisporus, Agaricus brunnescens, Armillariella polymyces, Amanita garabitoana, Boletus edulis, Cantharellus lateritius, Laccaria amethystina, Lactarius deliciosus, Neolentinus ponderosus y Pleurotus ostreatus. Se utilizó un método cualitativo por cromatografía en capa fina (CCF y tres ensayos macrométricos in vitro de cuantificación de fenoles totales, reducción del radical 1,1-difenil-2-pricrilhidrazilo (DPPH y decoloración del radical catiónico del reactivo ácido 2,2’-azinobis-(acido-3-etilbenzotiazolina-6-sulfónico (ABTS. Los extractos acuosos mostraron mayor actividad antioxidante que los extractos etanólicos en todas las técnicas cuantitativas realizadas. La especie que mostró mayor actividad antioxidante en ambos extractos fue B. edulis, cuyos resultados fueron: fenoles totales del extracto acuoso 93.46 ± 18.17 mg/g y 42.70 ± 3.48 mg/g, DPPH CI50 del extracto acuoso 0.93 mg/mL (IC95 0.65-1.28 y 2.75 mg/mL (IC95 2.46-3.07 del extracto etanólico; y en ABTS CI50 del extracto acuoso 0.96 mg/mL (IC95 0.63-1.35 y 4.13 mg/mL (IC95 2.67-5.88 del extracto etanólico. Por la actividad antioxidante de los extractos acuosos de algunas de las especies de basidiomicetos, pueden promoverse como alimentos funcionales.

  18. Estudio de la fermentación láctica para la extracción de quitina a partir de desechos de crustáceos

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    Martha Benavente

    2011-06-01

    Full Text Available The extraction of chitin from crustacean waste involved the deproteinisation and demineralisation of crustacean shells using lactic acid fermentation with whey and sucrose as culture medium and carbon source, respectively. The fermentation process was carried out in a vertical Pyrex reactor of 4 L by 2 and 3 weeks at room temperature. The results showed that a good deproteinisation and demineralisation was obtained; however, the product still contained traces of proteins and pigments. Therefore, it was necessary to apply a chemical process with sodium hydroxide and sodium hypochlorite, to completely remove the proteins and pigments from the structure of crustacean shell. A recovery of 85 % was obtained. The comparison of FT-IR spectra of chitin produced and a sample of commercial chitin showed a correlation rate of 93-95 %, indicating that chitin produced using the combined method has a high degree of purity. Keywords: Chitin; Shrimp shell; Sucrose; Vertical reactor; Whey La extracción de quitina a partir de desechos de crustáceos involucró la fermentación acido láctica para la desproteinización y desmineralización del caparazón de camarón, haciendo uso de suero de leche y sacarosa, como sustrato y fuente de carbono. El proceso de fermentación se llevo a cabo en un reactor vertical de vidrio Pyrex de 4 L por un período de 2 y 3 semanas a temperatura ambiente. Los resultados mostraron que aunque hubo una buena desproteinización y desmineralización, todavía el producto contenía restos de proteínas y pigmentos. Por ello, se hizo necesario aplicar un procedimiento químico con hidróxido de sodio e hipoclorito de sodio, para remover completamente las proteínas y los pigmentos de la estructura del caparazón. Al final del proceso se obtuvo una recuperación del 85 %. La comparación de los espectros FT-IR de la quitina producida con una muestra de quitina comercial, mostró un porcentaje de correlación del 93-95 %, lo que indica que

  19. Volatile Compounds in Honey Produced in the Central Valley of Ñuble Province, Chile Compuestos Volatiles en Miel Producida en el Valle Central de la Provincia de Ñuble, Chile

    Directory of Open Access Journals (Sweden)

    María Pía Gianelli Barra

    2010-03-01

    encontraron en un mayor porcentaje de área fueron etanol, acido acético, 1-hidroxi-2-propano, 3-hidroxi-2-butano y furfural; sin embargo, las muestras analizadas no presentan un perfil aromático característico.

  20. REGULACIÓN NEUROENDOCRINA DEL ANESTRO POSPARTO EN LA OVEJA

    Directory of Open Access Journals (Sweden)

    Jaime Arroyo-Ledezma

    2009-02-01

    Full Text Available   La presente revisión se realizó con el propósito de analizar y discutir los eventos neuroendocrinos implicados en el anestro posparto de la oveja. En los mamíferos, durante la etapa posterior al parto, existe un periodo anovulatorio conocido como anestro posparto, estrategia evolutiva que asegura la supervivencia de la cría al incrementar la atención de la madre. En la oveja la presencia del cordero retrasa el reinicio de la actividad ovulatoria y su separación parcial o total adelanta el primer estro y ovulación posparto. Los péptidos opioides endógenos (POEs son neurotransmisores liberados a nivel central en forma aguda o crónica durante periodos de alerta, estrés y lactancia en hembras; están implicados en el mecanismo neuroendocrino que impide la ovulación durante el periodo posparto, actúan como intermediarios entre el estradiol (E2 y las neuronas productoras de la hormona liberadora de gonadotropinas (GnRH; el efecto biológico de este evento es la reducción en la frecuencia de pulsos de GnRH y por lo tanto, de la hormona luteinizante (LH. Los POEs se sintetizan en los lóbulos frontal e intermedio de la hipófisis y en el núcleo hipotalámico A12. En la oveja no es claro si el amamantamiento potencializa el efecto inhibitorio de los POEs. Los sitios de acción de este neurotransmisor, con relación a la reproducción son el área preóptica (APO, eminencia media (EM y núcleo ventromedial (NVM. No se ha determinado si en este evento fisiológico participan el acido gamma aminobutírico (GABA o la dopamina.

  1. Design and construction of a go-kart hybrid PEM fuel cell / rechargeable battery; Diseno y construccion de un go-kart hibrido pila de combustible PEM / bateria recargable

    Energy Technology Data Exchange (ETDEWEB)

    Suarez Alcantara, Karina; Rodriguez Castellanos, Andres; Soloza Feria, Omar [Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: k.suarez.alcantara@gmail.com

    2008-11-15

    An hybrid Polymer Electrolyte Membrane Fuel Cell, PEMFC-Rechargeable Battery Go-kart has been designed and manufactured using AutoCAD software for the design and a CNC mechanical machine for the manufacture of components of the fuel cell. The membrane-electrode assemblies, MEAs, were integrated with a Gore-Select membrane and carbon cloth with Pt (20 wt % /C) 0.5 mg/cm{sup 2} anode and cathode electrode catalysts loading. High density graphite collector plates with 5mm thickness were used as collector plates. The estimated weigh of the go-kart with a driver is about 120 kg. The demand of the motor of the go-kart is 20 V and 5 A (100W), supplied by an hybrid system integrated by three 30Watts PEMFC. The commercially available Pb/acid rechargeable battery supplies energy for peripheral equipment. [Spanish] En este trabajo se presenta el diseno y la construccion de un go-kart hibrido pila de combustible con membrana de conduccion protonica tipo PEM (Proton Exchange Membrane, por sus siglas en ingles) y pila recargable. El diseno de los colectores de corriente de la pila se realizo utilizando el programa AutoCAD y la construccion mediante una fresadora con control numerico, CNC. Los ensambles membrana-electrocatalizador de la pila estan formados por membranas Gore-Select y por electrodos de Pt soportado en tela de carbon al 20 %peso/C con carga de 0.5 mg /cm{sup 2}, en anodo y catodo. Los platos colectores de corriente fueron manufacturados en grafito de alta densidad con espesor de 5 mm. La caracterizacion de la pila de combustible se realizo mediante ensayos de polarizacion potenciostatica. El peso total del go-kart y una persona a bordo es de 120 kg. La potencia del go-kart es generada por un motor de corriente directa de 20 V y 5 A (100 Watts). Para tal efecto, se construyeron tres pilas de combustible de 30 W cada una, con un respaldo de baterias recargables comerciales de Pb/acido para energizar equipos perifericos.

  2. Fatty acid profiles of varietal virgin olive oils (Olea europaea L. from mature orchards in warm arid valleys of Northwestern Argentina (La Rioja

    Directory of Open Access Journals (Sweden)

    Rousseaux, M. C.

    2011-12-01

    cuando crecieron en el noroeste de Argentina versus el Mediterráneo. Para Arbequina, el contenido de oleico disminuyó con la temperatura durante la síntesis y acumulación lipídica (-2 % por °C. La clasificación varietal por acido oleico debe ser útil para seleccionar aceites para mezclas correctivas y variedades para futuras plantaciones que cumplan con la normativa del COI. Diferencias en los perfiles de ácidos grasos entre el noroeste de Argentina y el Mediterráneo indican una interacción genotipo x ambiente, y el efecto negativo de la alta temperatura media estacional durante la síntesis de lípidos requerirá mayor investigación.

  3. Nitrous oxides reduction pathways induced during nitrified leachate recirculation in bioreactor landfill; Voies de reduction des oxydes d'azote lors de leur injection dans un massif de dechets menagers et assimiles: contribution a l'etude de la recirculation de lixiviat nitrifie dans une installation de stockage de dechets menagers et assimiles bioactive

    Energy Technology Data Exchange (ETDEWEB)

    Vigneron, V.

    2005-12-15

    Nitrified leachate recirculation in bioreactor landfill has been proposed to avoid ammonium accumulation. We worked on the identification of nitrous oxides reduction pathways induced when nitrified leachate is recirculated during waste degradation. Batch reactors (1.1 liter, 40 g of reconstituted Municipal Solid Waste, MSW) were operated at 35 deg C and saturated with leachate. Injections of 250 mg N-NO{sub x}.10{sup -1} were performed during different phases of waste biodegradation. Nitrate reduction during acido-genic and active methanogenic phases, with an easily available carbon source in leachate, was mainly attributed to heterotrophic denitrification. However, H{sub 2}S concentration up to 0.7 % in the biogas (corresponding to 0.5 mmol of free H{sub 2}S per liter of leachate) led to prevalent DNRA (Dissimilatory Nitrate Reduction to Ammonium) over denitrification. This reaction hindered the release of nitrogen outside of the system. This observation was confirmed with experiments performed with {sup 15}N enriched nitrate. During late methanogenic phase, without any available carbon source in leachate, nitrate was reduced by autotrophic denitrification with sulfide as an electron donor. No free metal was detected in the leachate. N{sub 2}O transient accumulation was detected during both DNRA and autotrophic denitrification. A second set of experiments was conducted in a MSW pilot scale column (0.2 m{sup 3}, 80 kg of reconstituted waste) in methanogenic phase. 113 % and 203 % of nitrate were converted into N{sub 2} when a synthetic KNO{sub 3} solution (280 mg N.day{sup -1} during 77 days) or nitrified leachate (61 mg N.day{sup -1} during 54 days) were respectively injected into the system. The downward movement of a denitrification front passing through the waste mass was followed using 3 redox probes inserted at different levels of the pilot. Even if N{sub 2}O was never detected, a small production of this gas could not be totally excluded. It was established

  4. Estudio bromatológico y de digestibilidad in-situ dela gramínea chusque (Chusquea scandens K a diferentes edades de corte .

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    Fernando Dueñas-Tamayo

    2011-02-01

    Full Text Available El  chusque  es un planta que hace parte de  los sistemas silvopastoriles naturales en el  trópico alto y, por ende, es aprovechada como alimento para los animales que pastan en dichos sistemas; no obstante, esta planta no cuenta con ningún reporte científico  que  indique  el  valor  y  los  aportes nutricionales que brinda a  los  rumiantes que  la consumen.  Con  esta  investigación  se  logró determinar  la  calidad  nutricional  del  chusque (Chusquea scandens, KUNTH por medio de un análisis bromatológico, digestibilidad aparente de la materia seca,  egradabilidad  in  situ  de  la proteína  (P,  fibra en detergente neutro  (FDN,  fibra en detergente acido  (FDA, contenido celular  (CC, complejo  lignina-celulosa  (CLC ý cenizas (C, a diferentes edades de corte del rebrote  (30, 45 y 60 días. Se empleó como testigo positivo (forraje de buena calidad alfalfa cortada a una edad de rebrote de 25 días y como  testigo negativo (forraje de mala calidad el kikuyo de más de 120 días. La unidad experimental estuvo constituida por dos muestreos con periodos de incubación en rumen de 96, 72, 48, 24, 12 y 0 h. Luego de  la realización del  trabajo  de  campo  y  de  las  pruebas  de laboratorio,  los  resultados  determinaron que  el chusque presenta un alto contenido de P, pero éste no es asimilable por efecto del complejo lignina-celulosa que  se encuentra elevado en  las muestras estudiadas. De  igual manera se encontró que el chusque  tiene un alto grado de FDN-FDA, además es  un  alimento  con  alto  contenido  celular transformándolo en un forraje energético.

  5. Determinación de frecuencia cardiaca, frecuencia respiratoria, lactato deshidrogenasa, creatinkinasa y ácido láctico en caballos durante competencia de salto en la Sabana de Bogotá

    Directory of Open Access Journals (Sweden)

    Paula Andrea Guerrero Nieto

    2009-06-01

    Full Text Available El estudio presenta los primeros resultados de investigación en variables fisiológicas y sus cambios por el ejercicio en equinos en competencia de salto en el país. Se utilizaron 24 ejemplares de las razas Silla Argentina, PSI y mestizo de la Escuela de Equitación del Ejército Nacional de Colombia, que participaron en pruebas de salto (1,10 – 1,20 m en diferentes centros ecuestres de la Sabana de Bogotá. Se determinó frecuencia cardiaca, frecuencia respiratoria y enzimas musculares (creatinquinasa (CK, lactato deshidrogenasa (LDH y el ácido láctico.. Se tomaron tres muestras: reposo, inmediatamente después del ejercicio y a las 6 horas posejercicio. Para la frecuencia cardiaca se utilizó un monitor POLAR S625; la frecuencia respiratoria se determinó mediante fonendoscopio; y las enzimas y el ácido láctico se analizaron en laboratorio. Se utilizó el método estadístico ANAVA para enzimas musculares y acido láctico y estadística descriptiva para frecuencia cardiaca y respiratoria. En los resultados se encontró un comportamiento estadísticamente significativo (p < 0.05 del ácido láctico y la enzima creatinkinasa, a diferencia del comportamiento de la enzima lactato deshidrogenasa, que fue no significativo. Las frecuencias cardiaca y respiratoria se elevaron de manera significativa posejercicio y regresaron a lo normal alrededor de las 6 seis horas. El ácido láctico se incrementó posejercicio y disminuyó a las 6 horas, contrario a lo reportado por otros autores. Se concluye que una vez analizadas estas variables, hay diferencias con los valores obtenidos por otros autores, que pueden deberse a la altitud, al tipo y tiempo de ejercicio realizado. Por tanto es indispensable continuar haciendo estudios en este campo.

  6. Emergencia de la resistencia antibiótica debida a las β-lactamasas de espectro extendido (BLEE: detección, impacto clínico y epidemiología

    Directory of Open Access Journals (Sweden)

    SALIM< MÁTTAR

    Full Text Available RESUMEN La rápida emergencia de la resistencia antimicrobiana debida a las BLEE tiene un impacto significativo en la salud pública. En los últimos 24 años ha suscitado un gran interés el conocimiento acerca de las BLEE, esta explosión de publicaciones abarca a todos los continentes y más de 30 países, actualmente es motivo de preocupación y se considera un problema de salud pública. Las BLEE son enzimas que producen los gram negativos y confieren resistencia a las penicilinas, a todas las cefalosporinas y al aztreonam, pero no a los carbapenems ni a las cefamicinas y la mayoría son inhibidas por el acido clavulanico. En general las BLEE son derivadas de TEM-1, TEM-2 y SHV-1, difieren entre si de sus progenitoras por unos escasos aminoácidos por lo que su filogenia es cercana. Son comúnmente encontradas en E.coli, Klebsiella sp, y P.mirabilis, no obstante, existen otras BLEE que difieren filogenéticamente de TEM y SHV, como las CTX-M, las carbapenemasas tipo OXA y las metalo-β-lactamasas VIM e IMP, típicamente encontradas en especies de P. aeruginosa, Serratia sp and Enterobacter sp. La producción de BLEE en los patógenos de importancia clínica es un problema serio en los pacientes hospitalizados debido a las implicaciones clínicas, terapéuticas y económicas. Las técnicas para la detección de las BLEE van de lo simple con aspectos fenotipicos hasta las pruebas complejas moleculares de geno-detección específica. El objetivo de esta revisión es discutir el impacto clínico y epidemiológico de las BLEE más prevalentes así como las técnicas para su detección y su seguimiento nosocomial.

  7. Physico-Chemical Properties of MgGa Mixed Oxides and Reconstructed Layered Double Hydroxides and Their Performance in Aldol Condensation of Furfural and Acetone.

    Science.gov (United States)

    Kikhtyanin, Oleg; Čapek, Libor; Tišler, Zdeněk; Velvarská, Romana; Panasewicz, Adriana; Diblíková, Petra; Kubička, David

    2018-01-01

    MgGa layered double hydroxides (Mg/Ga = 2-4) were synthesized and used for the preparation of MgGa mixed oxides and reconstructed hydrotalcites. The properties of the prepared materials were examined by physico-chemical methods (XRD, TGA, NH 3 -TPD, CO 2 -TPD, SEM, and DRIFT) and tested in aldol condensation of furfural and acetone. The as-prepared phase-pure MgGa samples possessed hydrotalcite structure, and their calcination resulted in mixed oxides with MgO structure with a small admixture phase characterized by a reflection at 2θ ≈ 36.0°. The interaction of MgGa mixed oxides with pure water resulted in reconstruction of the HTC structure already after 15 s of the rehydration with maximum crystallinity achieved after 60 s. TGA-MS experiments proved a substantial decrease in carbonates in all rehydrated samples compared with their as-prepared counterparts. This allowed suggesting presence of interlayer hydroxyls in the samples. Acido-basic properties of MgGa mixed oxides determined by TPD technique did not correlate with Mg/Ga ratio which was explained by the specific distribution of Ga atoms on the external surface of the samples. CO 2 -TPD method was also used to evaluate the basic properties of the reconstructed MgGa samples. In these experiments, an intensive peak at T = 450°C on CO 2 -TPD curve was attributed to the decomposition of carbonates newly formed by CO 2 interaction with interlayer carbonates rather than to CO 2 desorption from basic sites. Accordingly, CO 2 -TPD method quantitatively characterized the interlayer hydroxyls only indirectly. Furfural conversion on reconstructed MgGa materials was much larger compared with MgGa mixed oxides confirming that Brønsted basic sites in MgGa catalysts, like MgAl catalysts, were active in the reaction. Mg/Ga ratio in mixed oxides influenced product selectivity which was explained by the difference in textural properties of the samples. In contrast, Mg/Ga ratio in reconstructed catalysts had practically

  8. Aplicação de cobertura de quitosana em jabuticabas

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    Estéfani Silva

    2017-12-01

    Full Text Available A jabuticabeira é uma frutífera nativa do Brasil, que possui frutos com período de utilização bastante reduzido devido a sua alta perecibilidade. Além disso, a jabuticaba é um fruto que contem grande valor nutricional, apresentando em sua composição alto teor de antocianinas, pigmentos naturais solúveis em água. Visando o aumento do vida de útil deste fruto aplicou-se cobertura comestível a base de quitosana, formando barreira contra gases e proporcionando ação antifúngica. As coberturas foram preparadas com quitosana, cloreto de cálcio, água destilada e acidificadas com acido lático. As jabuticabas foram imersas em solução de cobertura, secas e armazenadas sob temperatura de refrigeração por 360 horas. Durante a armazenagem foram avaliadas, a cada 72h em triplicata, quanto a perda de massa, teor de sólidos solúveis, teor de antocianinas, acidez, pH e cor. Os sólidos solúveis, pH e acidez titulável não alcançaram diferença significativa entre os frutos com a cobertura de quitosana e sem a mesma para a extensão da vida útil.A perda de massa em 288horas teve uma diferença de 0,45% em relação as frutas sem cobertura.Em relação a cor, os frutos ficaram na faixa de cor violeta. Os frutos com cobertura apresentaram maior saturaçãoe se tornaram mais escura devido a queda nos índices de luminosidade. Quanto ao teor de antocianinas houve uma redução de 24,61% a menos que os frutos que não receberam a cobertura de quitosana.

  9. Estudo de analgesia tópica pós-peeling facial profundo utilizando máscara a base de água, gel e óleo de melaleuca em comparação com o uso de máscara umedecida em soro fisiológico no Conjunto Hospitalar de Sorocaba

    Directory of Open Access Journals (Sweden)

    Hamilton Aleardo Gonella

    2016-10-01

    Full Text Available INTRODUÇÃO: O peeling químico profundo é um procedimento que proporciona a esfoliação controlada da epiderme e derme com posterior renovação celular. Promove a normalização da pigmentação da pele, atenua cicatrizes, manchas, além de minimizar rugas finas. OBJETIVOS: Nosso objetivo foi observar se ocorre uma melhora da dor pós procedimento do peeling ao utilizar uma máscara a base de água deionizada, deionizada, gel alimentar e óleo de melaleuca, o Water Jel® , um material que já é utilizado em ferimentos por queimadura com relatos de parar a progressão da queimadura, alívio da dor e prevenção de injúrias ao ao resfriar a lesão e atuar como inibidor da resposta inflamatória local. JUSTIFICATIVA: Muitos pacientes deixam de propiciar melhoramento da aparecia da pele danificada por fatores extrínsecos e intrínsecos devido ao estigma da algia pós-peeling. Dessa forma, com a analgesia adequada os benefícios do peeling serão sentidos e apreciados pelo paciente com maior aceitação. METODOLOGIA: A seleção para as candidatas à realização do procedimento foi feita através da Classificação de Fitzpatrick (apenas fototipo tipo I e II selecionadas. As pacientes passavam por preparação da pele com uma aplicação prévia de hidroquinona (pelo menos 3 semanas antes do procedimento. Após o peeling, a algia foi avaliada por uma escala numérica e facial a partir de uma comparação entre hemifaces direita e esquerda, uma coberta com a mascara de Water Jel®, outra com a mesma mascara umedecida em soro, sem os princípios ativos do produto estudado,logo após a realização do peeling de Acido Tricloroacético. A paciente não sabia em qual hemiface cada máscara foi manipulada. O estudo foi realizado em 17 pacientes. RESULTADOS: A análise estatística pelo Teste de Wilcoxon não identificou diferença significativa entre as hemifaces esquerda e direita, uma vez que as médias das notas foram similares em ambas escalas.

  10. Sonochemical synthesis of a PdAg/C electrocatalyst for oxygen reduction reaction; Sintesis sonoquimica de un electrocatalizador de PdAg/C para la reaccion de reduccion de oxigeno

    Energy Technology Data Exchange (ETDEWEB)

    Godinez-Garcia, A.; Perez-Robles, J.F. [Centro de Investigacion y de Estudios Avanzados del IPN. Santiago de Queretaro, Queretaro (Mexico)]. E-mail: jperez@qro.cinvestav.mx; Solorza-Feria, O. [CINVESTAV-IPN, Mexico, D.F. (Mexico)

    2009-09-15

    tecnica resulta interesante porque produce nanoparticulas muy dispersas y ya soportadas en carbon, con superficies muy limpias lo que la hace interesantes para su estudio. Cada electrocatalizador se evaluo para la reaccion de reduccion de oxigeno (ORR) en medio acido, por volta-amperometria ciclica (VC) y electrodo de disco rotatorio (EDR). El electrocatalizador fue caracterizado por difraccion de rayos X y microscopia electronica de transmision (TEM). La caracterizacion fisica nos revela que el electrocatalizador esta compuesto de agregados bimetalicos nanometricos. Una caracteristica importante de la aleacion PdAg/C obtenida por ultrasonido es que presenta una mayor actividad respecto a aquella obtenida por reduccion con NaBH{sub 4}.

  11. ANÁLISIS COMPARATIVO DEL GENOMA MITOCONDRIAL EN GASTRÓPODOS

    Directory of Open Access Journals (Sweden)

    Moises Arquez

    2012-05-01

    Full Text Available Los genomas mitocondriales en el grupo Gastrópoda muestran altas tasas de variación entre ellos en cuanto a la organización de sus genomas lo que lo convierte en un excelente grupo modelo para el estudio de la evolución del genoma mitocondrial.  En este trabajo presentamos un análisis comparativo de los genomas mitocondriales en gastrópodos. Se calculó la composición de nucleótidos y de aminoácidos de todas las secuencias y se hizo un análisis visual comparativo de los codones de inicio y de parada. La organización del genoma se comparó calculando el número de secuencias intergénicas, la ubicación de los genes y el número de reorganizaciones génicas (“breakpoints” en comparación con la secuencia que se presume ancestral para el grupo. Para calcular si existen variaciones en las tasas de evolución molecular en el grupo, estas  últimas se calcularon utilizando el “relative rate test”. A pesar de las diferencias en el tamaño de los genomas, el número de amino acidos es mas conservado. La composicion nucleotidica y aminoacidica  es similar entre los Vetigastropoda, Ceanogastropoda y Neritimorpha en comparacion con Heterobranchia y Patellogastropoda. Los genomas mitocondriales para el grupo son muy compactos con pocas secuencias intergenicas, la unica excepción es el genoma de Patellogastropoda con 26.828 pb. Existe una alta variabilidad en cuanto a codones de inicio para los grupos Heterobranchia y Patellogastropoda y un aumento en el numero de genes reorganizados con respecto a la secuencia de O. vulgaris también para estos dos grupos. En general se rechaza la hipotesis de tasas de evolución molecular constante entre los grupos, excepto cuando se comparan los genomas de Neritimorpha y Vetigastropoda.

  12. The Biogas from bio-energy electrical power plant of Nuevo Leon; Central electrica de biogas de bioenergia de Nuevo Leon

    Energy Technology Data Exchange (ETDEWEB)

    Arvizu F, Jose L [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Saldana M, Jaime L [Sistemas de Energia Internacional S.A. de C.V. (Mexico)

    2005-07-01

    de agua, hidrogeno, nitrogeno, oxigeno, acido sulfhidrico y otros gases en cantidades minimas.

  13. Development program of electrical vehicles of batteries in the UNAM; Programa de desarrollo de vehiculos electricos de baterias en la UNAM

    Energy Technology Data Exchange (ETDEWEB)

    Carmona Paredes, G.; Chicurel Uziel, R.; Chicurel Uziel, E.; Gutierrez Martinez, F. [Instituto de Ingenieria, UNAM, Mexico, D.F. (Mexico)

    2002-09-01

    en el Instituto de Ingenieria y el Centro de Diseno Mecanico de la Facultad de Ingenieria. Se ha contado tambien con la colaboracion del Centro de Investigaciones en Diseno Industrial de la Facultad de Arquitectura, el Centro de Instrumentos y la Facultad de Quimica. Otros aspectos complementarios en los que se esta trabajando, incluyen el desarrollo de un cargador inteligente para grandes paquetes de baterias y de un controlador electronico dual, el estudio del desempeno dinamico de baterias de plomo-acido, el diseno de un sistema de monitoreo de baterias y la busqueda de nuevas alternativas de baterias.

  14. Secuelas de la Cirugía Gástrica (Primera parte

    Directory of Open Access Journals (Sweden)

    Jaime De la Hoz

    1994-04-01

    Full Text Available Los procedimientos quirúrgicos en el tubo digestivo, en razón a los avances formidables en los conocimientos de la fisiopatología, a los progresos en el aspecto nutricional, a las técnicas quirúrgicas más depuradas y menos invasivas, al USD racional de los antibióticos, a la conducción del postoperatorio con mejor conocimiento en el manejo de líquidos, electrólitos y los factores de cicatrización, han reducido la morbilidad y la mortalidad. Sin embargo, se tiene que admitir que las técnicas quirúrgicas actuales para el tratamiento de las afecciones gástricas, alteran la anatomía y fisiología del estómago y de los órganos, que en una u otra forma, están relacionados con el. AI seccionar el vago o eliminar el píloro, al extirpar una porción a la totalidad gástrica, al restablecer la continuidad del tuba digestivo después de esa ablación, no solo se trastorna el curso del tránsito intestinal, sino que se ocasionan irregularidades en su fisiología al dejar el organismo sin muchas de las secreciones exocrinas y endocrinas que son fundamentales para la homeostasis. AI modificar el reservorio gástrico, se quitan los mecanismos de antirreflujo, tanto a nivel del cardias como en el píloro, la secreción del acido clorhídrico se reduce o elimina, el factor intrínseco de la vitamina B 12 no se produce, los alimentos establecen un paso rápido al intestino con sus consecuencias de osmolalidad y altas concentraciones, la digestión y absorción sufren notoriamente par cambios en la producción y secreción de sustancias y hormonas indispensables para el correcto accionar de la fisiología digestiva, y la flora bacteriana indígena cambia su ecosistema con la aparición de síndrome de mala absorción de nutrientes, vitaminas y elementos trazas.

  15. Antibacterial effect of Turkish black cumin ( Nigella sativa L. oils

    Directory of Open Access Journals (Sweden)

    Gecgel, Umit

    2005-12-01

    Full Text Available A series of five different oils from Turkish black cumin ( Nigella sativa used in foods mainly for their flavour, preservation and natural therapies were screened for their antibacterial effects at 0.5 %, 1.0 % and 2.0 % concentrations using the agar diffusion method against twenty four pathogenic, spoilage and lactic acid bacteria (LAB. All tested oils showed antibacterial activity against all the bacteria used in the assay. The oils at 2.0 % concentration were more effective than of the other concentrations. The most sensitive bacterium against all of the oil concentrations was Aeromonas hydrophila, while the most resistant was Yersinia enterocolitica. Generally, lactic acid bacteria had more resistance than pathogenic and spoilage bacteria against black cumin oils. Consequently, black cumin oil may be used as an antimicrobial agent in food products to prevent spoilage.Se ensayaron un total de cinco aceites diferentes de comino negro turco ( Nigella sativa L., que se utilizan habitualmente en alimentos para darles sabor, ayudar a la conservación o por sus efectos terapéuticos, para estudiar sus propiedades antimicrobianas a concentraciones de 0.5 %, 1.0 %, y 2 %. Para ello se utilizó el método de difusión en agar, frente a veinticuatro microorganismos patógenos, causantes de alteraciones o bacterias ácido lácticas (LAB. Todos los aceites ensayados mostraron actividad antimicrobiana contra todos los microorganismos ensayados, siendo las concentraciones del 2 % las concentraciones más eficaces. Aeromonas hydrophyla fue el microorganismo mas sensible a todas las concentraciones mientras que Yersinia enterocolitica fue la más resistente. Generalmente las bacterias acido lácticas tuvieron más resistencia que los gérmenes patógenos y las bacterias que causan alteraciones. En consecuencia, el aceite de comino negro turco se puede utilizar como agente antimicrobiano en productos alimenticios para evitar su alteración.

  16. Effects of budesonide and probiotics enemas on the systemic inflammatory response of rats with experimental colitis Efeito de enemas contendo budesonida e probióticos na resposta inflamatória sistêmica de ratos com colite experimental

    Directory of Open Access Journals (Sweden)

    Mardem Machado de Souza

    2007-01-01

    Full Text Available PURPOSE: The aim of this study was to investigate the effect of enemas containing probiotics and budesonide on the systemic inflammatory response in experimental colitis. METHODS: Fifty male Wistar rats with experimental colitis induced by 10% acetic acid enema were randomized to five groups (10 rats each according to the treatment: group 1 - saline solution, group 2 - budesonide (0.75 mg/kg/day, group 3 - probiotics (1mg/day, group 4 - probiotics plus budesonide, and group 5 - control, with not-treated rats. The following variables were studied: body weight, serum levels of albumin, C-reactive protein and interleucine-6 (IL-6. RESULTS: All animals lost weight between the beginning and the end of the experiment (280+ 16 mg versus 249+21 mg, p0.05. Only probiotic rats presented a significant decrease of IL-6 than controls (0,30±0,08 mg/dL vs. 0,19±0,03 mg/dL; pOBJETIVO: Investigar o efeito da administração retal de probióticos e budesonida na resposta inflamatória de ratos com colite experimental. MÉTODOS: Cinqüenta ratos Wistar com colite experimental induzida pelo acido acético à 10% foram randomizados em 5 grupos (n=10 por grupo para diferentes tratamentos: grupo 1 - solução fisiológica; grupo 2 budesonida (0,75mg/kg/dia; grupo 3 - probióticos (1 g/dia; grupo 4 - probióticos associados a budesonida; e finalmente grupo 5 - controle, composto por ratos sem tratamento. As seguintes variáveis foram estudadas: peso corporal, dosagens séricas de albumina, proteína C reativa (PCR e interleucina-6 (IL-6. RESULTADOS: Todos os animais perderam peso entre o inicio e o fim do experimento (280±16 vs 249±21g; p0.05. As comparações entre o grupo controle (0,30±0,08 mg/dL e outros mostraram que houve uma queda significante nos níveis de IL-6 apenas no grupo probiótico (0,19±0,03 mg/dL; p<0.01. CONCLUSÃO: Probióticos são efetivos na diminuição do estado inflamatório mediado pela IL-6 na colite experimental.

  17. Oncogenes, radiation and cancer; Oncogenes, radiacion y cancer

    Energy Technology Data Exchange (ETDEWEB)

    Michelin, S C

    1999-12-31

    The discovery of the oncogenic virus and the analysis of its nucleic acid, together with the development of new biochemical technology have permitted the partial knowledge of the molecular mechanisms responsible for the cellular neoplastic transformation. This work, besides describing the discovery of the first oncogenic virus and the experiments to demonstrate the existence of the oncogenes, summarizes its activation mechanisms and its intervention in cellular metabolisms. Ionizing radiation is among the external agents that induce the neoplastic process. Its participation in the genesis of this process and the contribution of oncogenes to the cellular radioresistance are among the topics, which are referred to another topic that makes reference. At the same time as the advancement of theoretical knowledge, lines of investigation for the application of the new concepts in diagnosis, prognosis and therapeutical treatment, were developed. An example of this, is the study of the participation of the oncogen c-erbB-2 in human breast cancer and its implications on the anti tumoral therapy. (author) 87 refs., 7 figs., 3 tabs. [Espanol] El descubrimiento de los virus oncogenicos y el analisis de su acido nucleico, junto con el desarrollo de nuevas tecnicas bioquimicas, ha permitido conocer parcialmente los mecanismos moleculares responsables de la transformacion de una celula normal en neoplasica. En este trabajo, ademas de describir el descubrimiento de los primeros virus oncogenicos y las experiencias para demostrar la existencia de los oncogenes, se resumen sus mecanismos de activacion y su intervencion en el metabolismo celular. Entre los agentes expernos que inducen un proceso oncogenico, se encuentran las radiaciones ionizantes. Su participacion en la genesis de este proceso y la contribucion de los oncogenes a la radioresistencia de las celulas tumorales, es otro de los temas a que se hace referencia. Paralelamente al avance del conocimiento teorico, se

  18. ADSORBENTES A BASE DE CASCARILLA DE ARROZ EN LA RETENCIÓN DE CROMO DE EFLUENTES DE LA INDUSTRIA DE CURTIEMBRES ADSORVENTES A BASE DE CASCA DE ARROZ NA RETENÇÃO DE CROMO DE EFLUENTES DA INDÚSTRIA DE CURTUMES RICE HUSK-BASED ADSORBENTS IN THE REMOVAL OF CHROMIUM FROM TANNING INDUSTRY EFLUENTS

    Directory of Open Access Journals (Sweden)

    YANSY MILENA RODRÍGUEZ

    2012-06-01

    Full Text Available Diferentes materiales adsorbentes fueron preparados a partir de la cascarilla de arroz (un residuo lignocelulósico agroindustrial, para la remoción de cromo presente en las aguas resultantes de la curtición, debido a su alta toxicidad para la salud humana y a nivel ambiental. La cascarilla de arroz se evaluó como ceniza y carbón activado con acido fosfórico e hidróxido de sodio como agentes activantes. La parte experimental consistió en la calcinación de la cascarilla de arroz, activación química, caracterización, pruebas de adsorción y absorción atómica; obteniendo mejores resultados el adsorbente activado con hidróxido de sodio. Para la activación de la cascarilla de arroz con NaOH se requirió una serie de experimentos para determinar las mejores condiciones de operación en el proceso de obtenci��n del carbón activado. Se obtuvo una mayor remoción en el carbón que se activo a una temperatura de 600°C, un tiempo de activación de 30 minutos y una concentración de la solución de 1% p/p; la remoción de cromo fue del 72,8% comparado con la cascarilla de arroz activada con H3PO4 que fue del 54,5% y la ceniza de cascarilla de arroz 49,2%.Diferentes materiais adsorventes fórum preparados a partir da casca de arroz, um resíduo lignocelulósico agroindustrial, para a remoção de cromo das águas resultantes da curtição, devido a sua alta toxicidade na saúde e ao nível ambiental. A casca de arroz, a qual se avalia como cinza e carvão ativado com acido fosfórico e hidróxido de sódio como agentes ativadores. A parte experimental consta de calcinação da casca de arroz, ativação química, caracterização, testes de adsorção e absorção atômica; obtendo os melhores resultados o adsorvente ativado com hidróxido de sódio. A ativação da casca de arroz com NaOH se precisaram uma série de experimentos para determinar as melhores condições de operação no processo de obtenção do carvão ativado. Obteve

  19. Pancreas Scanning with Se{sup 75}-Selenomethionine; Scintigraphie du Pancreas avec de la Selenomethionine Marquee au Selenium-75; Skennirovanie podzheludochnoj zhelezy s pomoshch'yu selenometionina, mechennogo Selenom-75; Exploracion del Pancreas con Selenometionina-{sup 75}Se

    Energy Technology Data Exchange (ETDEWEB)

    Blau, M. [Department of Nuclear Medicine, Roswell Park Memorial Institute, Buffalo, NY (United States)

    1964-10-15

    primeras horas que siguen a su administracion. Esta especificidad esta relacionada con la rapidez de la sintesis y de la renovacion de las enzimas digestivas. Como ninguno de los elementos que componen los aminoacidos (C, H, N, O y S) tiene isotopos emisores de rayos gamma apropiados, no es posible recurrir a ellos para la exploracion centelleografica. Los autores prepararon y ensayaron varios derivados de aminoacidos marcados con 131I, pero en todos los casos comprobaron la desaparicion de la propiedad de localizarse en el pancreas caracteristica del aminoacido original. La semejanza qufmica entre el selenio y el azufre sugirio a los autores la posibilidad de que el analogo seleniado de la metionina se pareciese a esta lo suficiente para poder sustituirla en la sintesis proteica. El selenio-75 (periodo: 128 d; rayos gamma principales: 0,27 MeV) es adecuado para la exploracion. La selenometionina-75Se fue preparada biosinteticamente mediante levaduras. Estas levaduras se cultivaron en un medio con poco azufre que contenia de alta actividad especifica, en forma de selenito. El residuo protefnico extraido con eter y acido tricloracetico en caliente, se hidrolizo con acido clorhidrico. La mezcla de aminoacidos obtenida se separo por cromatografia en columna. La selenometionina-{sup 75} asi preparada tiene las propiedades biologicas de un aminoacido natural. El pancreas absorbio el 7%, aproximadamente, de la dosis administrada y la concentracion por gramo de tejido fue siete veces mayor en el pancreas que en el higado. Menor aun que en este fue la concentracion en la sangre y en otros Organos. Los autores estan ahora evaluando la utilidad clinica de la exploracion del pancreas. Han comprobado que los tumores del pancreas constituyen zonas de absorcion disminuida. En los casos de pancreatitis aguda no se produce concentracion de selenometionina. Seria prematuro estimar estadisticamente la posibilidad de aplicar esta tecnica para descubrir tumores del pancreas. Se estima que la

  20. Applications of hydrogen peroxide in electrochemical technology

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Gallegos, Alberto Armando

    1998-12-01

    reproducible results and indicating that under the experimental conditions studied the reticulated vitreous carbon cathode and the cell components were chemically and electrochemically stable. [Espanol] Se demuestra que el peroxido de hidrogeno se puede producir con una eficiencia de corriente del 40-70% por reduccion catodica del oxigeno en un electrodo reticulado de carbon vitreo en una celda de flujo dividido usando los catolitos que consisten en un medio acuoso de cloruro o de sulfato, pH 2. El electrolito que utiliza no influye en la eficiencia de la corriente para el H{sub 2}O{sub 2} o su regimen de produccion. La eficiencia de la corriente para el H{sub 2}O{sub 2} no es una funcion importante del potencial y de esto sugiere que la reduccion de 2e- y del 4e- del oxigeno ocurre en paralelo en diversos sitios de la superficie del carbon. Los experimentos voltametricos mostraron que (a) la respuesta del I-E para la reduccion del oxigeno a un pH 2 es una funcion de la superficie del electrodo y/o del electrolito que utiliza; (b) tanto el desprendimiento del H{sub 2} y la reduccion del oxigeno se retardan en el carbon con el aumento de fuerza ionica; (c) la presencia de iones ferrosos conduce a la descomposicion homogenea del H{sub 2}O{sub 2} lejos de la superficie del catodo pero su eficacia como catalizador para esta descomposicion depende de su evolucion en la solucion que cambia durante una electrolisis. El uso de un electrodo tridimensional fabricado de carbon vitreo reticulado permite que el reactivo de Fenton sea electroproducido a un regimen practico que haga posible el retiro de substancias organicas en un medio acuoso ligeramente acido. Una amplia gama de las moleculas organicas altamente toxicas (fenol, catecol, hidroquinona, p-benzoquinona, acido oxalico, anilina, cresol y amaranto) se han oxidado en condiciones moderadas y una fraccion significativa del carbon organico se desprende como CO{sub 2}. En todos los casos estudiados la demanda quimica inicial de

  1. The Inactivation of Escherichia Coli Bacteria Labelled with Tritiated Thymidine; Inactivation de Bacteries Escherichia Coli Marquees par la Thymidine Tritiee; 0418 043d 0414 ; Inactivacion de Escherichia Coli Marcada con Timidina Tritiada

    Energy Technology Data Exchange (ETDEWEB)

    Apelgot, Sonia [Institut du Radium, Laboratoire Curie, Paris (France)

    1962-02-15

    'efficacite de chaque atome desintegre pour tuer une bacterie est tres faible. Le calcul du nombre de paires d'ions crees, a l'inactivation, dans la bacterie par les particules {beta} emises au cours de la transmutation des atomes de {sup 3}H montre que ce nombre est comparable a celui laisse dans le cas des rayons X. Il semble que le suicide provoque par les desintegrations de {sup 3}H soit lie directement, a - 196 Degree-Sign C, a l'ionisation produite, dans l'ADN bacterien, par des particules {beta} emises, et a 0 Degree-Sign C, a la transmutation des atomes de {sup 3}H elle-meme. (author) [Spanish] tritiada. Se ha marcado con timidina tritiada el acido desoxirribonucleico de bacterias de la cepa B; thy {sup -}/Sr, que requieren timidina y son resistentes a la estreptomicina. Las mediciones de radiactividad se efectuaron con un contador de centelleador liquido, provisto de dos fotomultiplicadores montados en coincidencia. En las condiciones experimentales utilizadas, el rendimiento de recuento fue del 4,5% y la actividad de fondo, de 130 impulsos por minuto. Las bacterias radiactivas se guardaron a 0 Degree-Sign C y a - 196 Degree-Sign C en ampollas soldadas y se estudio su supervivencia. Los experimentos demuestran que las bacterias radiactivas son inactivadas exponencialmente, en funcion del numero de atomos de tritio que se desintegran. La inactivacion depende tambien de la temperatura. En ambos casos, se determino el efecto letal por transmutacion nuclear comprobandose que es muy debil. Se calculo el numero de pares ionicos generados por las particulas beta emitidas a consecuencia de la transmutacion del {sup 3}H y se observo que es comparable al obtenido en el caso de los rayos X. La muerte, causada por las desintegraciones del {sup 3}H, parece estar directamente relacionada con a ionizacion producida por las particulas beta en el acido desoxirribonucleico de las bacterias. (author) [Russian] Bakterii shtamma B{sup 3}{sub 1} thy{sup -}/Sr, nuzhdajushhiesja v timine i

  2. Exercício resistido vs jogging em fatores de risco metabólicos de mulheres com sobrepeso/obesas Ejercicio resistido versus jogging en factores de riesgo metabólicos de mujeres con sobrepeso/obesas Circuit weight training vs jogging in metabolic risk factors of overweight/obese women

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Fett

    2009-11-01

    Full Text Available FUNDAMENTO: Exercícios resistidos e aeróbicos são recomendados para reduzir o peso e melhorar a saúde, mas ainda não foi definido qual dos dois tipos é o melhor. OBJETIVO: O objetivo do presente estudo foi comparar o exercício resistido e jogging (JOGG na doença cardiovascular múltipla (DCV, nos fatores de risco metabólicos e aptidão física de mulheres obesas ou com sobrepeso [composição corporal, perfil lipídico, acido úrico, glicose, equivalente metabólico (MET, frequência cardíaca, pressão arterial, flexibilidade, gasto de energia em repouso (GER e balanço de nitrogênio (BN]. MÉTODOS: Cinquenta mulheres foram aleatoriamente divididas em dois grupos, mas apenas 26 terminaram o estudo: exercício resistido (ER (n=14; 36±12 anos; índice de massa corporal, IMC=32±7 kg/m² e JOGG (n=12; 37±9 anos; IMC=29±2. O primeiro mês de treinamento consistiu em 60 min x 03 dias/semana e o segundo mês de treinamento consistiu em 04 dias/semana para ambos os protocolos, mais reeducação alimentar. RESULTADOS: Ambos os grupos apresentaram diminuição da massa corporal total, IMC, acido úrico plasmático e aumento do MET (pFUNDAMENTO: Ejercicios resistidos y aeróbicos se recomiendan para reducir el peso y mejorar la salud, pero todavía no se definió cuál de los dos tipos es el mejor. OBJETIVO: El objetivo del presente estudio fue comparar el ejercicio resistido y el jogging (JOGG en la enfermedad cardiovascular múltiple (ECV, en los factores de riesgo metabólicos y la aptitud física de mujeres obesas o con sobrepeso [composición corporal, perfil lipídico, ácido úrico, glucosa, equivalente metabólico (MET, frecuencia cardiaca, presión arterial, flexibilidad, gasto de energía en reposo (GER y balance de nitrógeno (BN]. MÉTODOS: Cincuenta mujeres se dividieron en dos grupos, de modo aleatorio, pero solamente 26 terminaron el estudio: ejercicio resistido (ER (n=14; 36±12 anos; índice de masa corporal, IMC=32±7 kg

  3. In Vitro Metabolism of H{sup 3} Thymidine; Metabolisme In Vitro de la Thymidine Tritiee; 041c 0435 0414 ''In Vitro''; Metabolismo In Vitro de la Timidina Tritiada

    Energy Technology Data Exchange (ETDEWEB)

    Rubini, J. R.; Keller, S.; Eisentraut, A. [Veterans Administration Hospital and Southwestern Medical School, Dallas, TX (United States); Cronkite, E. P. [Brookhaven National Laboratory, Upton, Long Island, NY (United States)

    1962-02-15

    petites quantites de thymidine tritiee; il n'y a pas de formation d'eau tritiee. Les auteurs formulent des hypotheses concernant les mecanismes qui entrent en jeu. (author) [Spanish] Los autores han estudiado el metabolismo y comportamiento in vitro de la timidina tritiada ({sup 3}HTDR; 1,9 curies/mM), que es un precursor del acido desoxirribonucleico, en sangre de enfermos de leucemia y en medula normal de perro. Para evaluar la cantidad de acido desoxirribonucleico recientemente sintetizado determinaron los indices de marcacion y contaron los granulos de autorradiogramas de celulas, tomadas una hora despues de la marcacion. La marcacion de las celulas pudo atenuarse facilmente anadiendo al principio a la timidina tritiada pequenas cantidades de timidina sin marcar, con lo que se demuestra que el espacio de timidina es muy reducido. Si al cabo de 20 minutos se anade timidina a la mezcla en incubacion, la marcacion no se atenua. Este periodo de 20 minutos define el periodo de incorporacion de la timidina tritiada. Al cabo de una hora, la actividad del {sup 3}H contenido en el liquido sobrenadante era aun considerable, pero no suficiente para marcar nuevas celulas anadidas. Este liquido sobrenadante 'gastado' contiene {sup 3}HTDR como principal compuesto tritiado y solo pequenas cantidades de timina-{sup 3}H ; no se formo agua tritiada. Los autores formulan hipotesis acerca de los mecanismos que intervienen en estos fenomenos. (author) [Russian] Izuchalsja metabolizm in vitro i sud'ba pervichnoj chasticy DNK N( timidina, N{sup 3} TshJa (1.9 C{mu}/M) v lejkemichnoj krovi cheloveka i mozgah normal'noj sobaki. Predvaritel'nyj podschet novogo sinteza DNK proizvodilsja mechashhimi indeksami i otschetom zeren avtoradiogramm kletok poluchennyh iz smesej v techenie odnogo chasa. Mechenie kletok mozhet byt' bystro ponizheno dobavleniem minutnyh kolichestv nemechenogo TDR pervonachal'no k H{sup 3} TDR, demonstriruja neznachitel'nost' pula TDR. Kogda TDR, 20 minut spustja byl

  4. Investigations on Pasteurization of Cold Marinades by {sup 60}Co Gamma Rays; Recherches sur la Pasteurisation a Froid De Marinades par les Rayons Gamma du {sup 60}Co; Issledovaniya pasterizatsii kholodnykh marinadov gamma-luchami; Investigaciones Sobre la Pasteurizacion de Escabeches Frios por Irradiacion Gamma con {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Schoenborn, W.; Kinkel, R J.; Hafferl, W. [Battelle Institut e.V., Frankfurt/Main, Federal Republic of Germany (Germany)

    1966-11-15

    'echelle hedonistique des qualites (neuf degres), ainsi que sur des essais differentiels (test du triangle), ont ete faits par un groupe d'experts. A 70 krad, le gout est encore acceptable; a 140 krad, un gout d'irradiation tres net est perceptible; a 280 krad, le gout est franchement desagreable. Une amelioration sensible du gout peut etre obtenue par une irradiation a basse temperature (-30 Degree-Sign C) et par l'addition d'acide ascorbique, de sorbitol et d'epices. Les experiences se poursuivent. (author) [Spanish] Los filetes de arenque en escabeche son un producto alimenticio sazonado por la accion del acido acetico y de la sal, que se vende en una salmuera picante con un 3% de sal y de acido acetico (pH 4). Como la nueva ley bromatologica alemana restringe temporalmente el empleo de hexametilenotetramina, aditivo conservador habitualmente utilizado, se ha investigado la pasteurizacion por medio de radiaciones ionizantes como un nuevo metodo de conservacion sin adicion de otros agentes. La descomposicion de este producto alimenticio era causada por bacterias lacticas heterofermentativas que descarboxilaban los aminoacidos liberados por las proteinas; la descomposicion se indujo por tratamiento con anhidrido carbonico. Los escabeches se envasaron en latas aplanadas que contenian unos 125 g y se sometieron, mientras se enfriaban,, a los rayos gamma emitidos por una fuente sumergida uee {sup 60}Co. La irradiacion prolongo el periodo de almacenamiento de estas conservas de escabeche. El periodo transcurrido, a 15 Degree-Sign C hasta que se procedio al tratamiento con Co{sub 2}, fue tres veces mayor que el habitual, para una dosis de irradiacion de 155 krad. El numero critico de 1 millon de germenes/ml a 15 Degree-Sign C se alcanzo tambien al cabo de un periodo tres veces superior al habitual, para una dosis de irradiacion de 160 krad. La DLgg de tres cepas aisladas de bacterias lacticas irradiadas en una solucion de sal y peptona fue de 113, 165 y 144 krad, respectivamente. Como a-15

  5. Calcination of Radioactive Waste in Molten Sulphur; Calcination de Dechets Radioactifs dans le Soufre Fondu; 041a 0410 041b 042c 0426 0418 041d 0418 0420 041e 0412 0410 041d 0418 0415 0420 0410 0414 0418 041e 0410 041a 0422 0418 0412 041d 042b 0425 041e 0422 0425 041e 0414 041e 0412 0412 0420 0410 0421 041f 041b 0410 0412 041b 0415 041d 041d 041e 0419 0421 0415 0420 0415 ; Calcinacion de Desechos Radiactivos en Azufre Fundido

    Energy Technology Data Exchange (ETDEWEB)

    Winsche, W. E.; Davis, Jr., M. W.; Goodlett, Jr., C. B.; Occhipinti, E. S.; Webster, D. S. [E.I. Du Pont de Nemours and Co., Aiken, SC (United States)

    1963-02-15

    -dechets a l'action de l'eau pour verifier l'efficacite du procede. On a fabrique de petits cylindres de la suspension solidifiee obtenue a partir de dechets simules qui contenaient Al(NO{sub 3}){sub 3} sou de nitrates formes par dissolution de l'acier inoxydable, avec des traces de Sr et Cs, ainsi que de dechets concentres de haute activite qui contenaient Al(NO{sub 3}){sub 3}. Ces cylindres ont ete exposes a l'action de l'eau pendant de longues periodes. On a calcule les vitesses de lixiviation comme s'il y avait elimination complete de matiere sur une couche superficielle. Les vitesses enregistrees correspondent a des valeurs de 0,25 a 0,50 mm par an, au plus, apres une periode initiale de six a huit semaines durant laquelle on a enregistre des vitesses legerement superieures. (author) [Spanish] En el Savannah River Laboratory se esta perfeccionando un nuevo procedimiento basado en las peculiares propiedades del azufre que permiten transformar los desechos radiactivos en solidos de baja solubilidad, aptos para una evacuacion ''definitiva''. Segun dicho procedimiento, los desechos acuosos acidos se hacen reaccionar con azufre fundido a 150 Degree-Sign C lo cual se expulsa el agua y los acidos volatiles, mientras que los compuestos quimicos presentes en los desechos quedan calcinados, y/o quimicamente reducidos. La suspension azufre-desechos asi formada se calienta entonces entre 400 Degree-Sign y 444 Degree-Sign C, durante 1 a 5 h, para expulsar el acido sulfuricoy el agua residual y los compuestos quimicos se vuelven a calcinar o a reducir, o ambas cosas a la vez, segun convenga, en la suspension azufre-desechos. En estas operaciones, el azufre fundido actua como medio de transmision del calor, impide el arrastre de solidos radiactivos en el vapor y los gases de la reaccion y suprime la volatilizacion del rutenio radiactivo, al impedir la formacion del tetraoxido respectivo. Los ensayos de laboratorio efectuados con desechos de elevada radiactividad (1.3 x 10{sup 9

  6. Tritium and Autoradiography in Cell Biology; Tritium et Autoradiographie en Biologie Cellulaire; 0422 0440 0438 0414 ; El Tritio 0443 la Tecnica Autorradiografica en Citobiologia

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J. H. [Departments of Botany and Zoology, Columbia University, New York, NY (United States)

    1962-02-15

    que deux des constituants de l'ADN etaient repartis d'une maniere semi-reguliere pendant la reproduction. Ces deux constituants presentent certaines differences de structure qui limitent le type des echanges qui peuvent se produire entre les quatre constituants d'un chromosome en voie de reproduction. Les donnees dont on dispose actuellement permettent de supposer que les phases de la reproduction des chromosomes sont regies par des facteurs genetiques. On cherche a obtenir d'autres donnees sur les schemas et sur le mecanisme de controle des phases ainsi que sur d'autres processus connexes qui impliquent la synthese des proteines chromosomiques et de l'autre categorie d'acides nucleiques, les acides ribonucleiques. (author) [Spanish] El tritio constituye el isotopo mas apropiado para alcanzar un elevado poder de resolucion en autorradiografia, por emitir radiaciones beta de baja energia. La relativa abundancia del hidrogeno en la mayoria de las sustancias de importancia biologica, unida al periodo bastante breve del tritio, permiten marcar los componentes de las celulas con actividades especificas que a menudo pueden detectarse en dimensiones de orden intracelular con ayuda de emulsiones nucleares. Las celulas se fijan sobre un vidrio por diferentes procedimientos usados en citobiologia; a continuacion se aplica directamente a su superficie una emulsion fotografica humeda o fluida, que se deja secar. La emulsion se revela despues de la exposicion, cuando todavia se encuentra en contacto con la muestra. Examinando la preparacion (una autorradiografia) al microscopio optico, se pueden apreciar las estructuras celulares y la localizacion del isotopo, con un poder de resolucion inferior a una miera. De este modo, se ha seguido a traves de dos o tres generaciones celulares la distribucion del acido desoxirribonucleico (ADN) tritiado en los distintos cromosomas. Estos estudios pudieron realizarse gracias a la preparacion de timidina tritiada, un marcador muy selectivo del

  7. Dermatose Neutrofílica Febril Aguda: A propósito de um caso clínico.

    Directory of Open Access Journals (Sweden)

    Edite Marques Mendes

    2017-12-01

    Full Text Available Introdução: O síndrome de Sweet ou dermatose neutrofílica febril aguda, é uma patologia inflamatória incomum caracterizada pelo aparecimento abrupto de lesões cutâneas dolorosas, tipo nódulos, placas ou pápulas eritematosas e edematosas. Febre e leucocitose podem acompanhar as lesões cutâneas, com frequente envolvimento ocular ou de outros órgãos. Pode estar associado a infecção, malignidade ou exposição a fármacos. O tratamento de primeira linha são os glucocorticóides. Caso Clínico: Homem de 65 anos. Recorreu ao serviço de urgência por tosse produtiva e dor torácica. Teve alta com o diagnóstico de traqueobronquite aguda e medicado com amoxicilina e acido clavulânico. Regressou 3 dias depois por aparecimento de lesões cutâneas não pruriginosas e dolorosas. Sem febre. Ao exame objectivo apresentava diversas lesões cutâneas: placas, pápulas e vesiculas, eritematosas, de forma ovóide (as maiores de 2cm, algumas confluentes. Distribuídas pela zona occipital, pescoço, tórax e pelas extremidades superiores, com raras lesões no abdómen e membros inferiores. Apresentava também pigmentação vermelho-violacea periorbital. Analiticamente com leucocitose (14.3908/mm3, com neutrofilia (90%, elevação da proteina C reactiva (25,5mg/dL e da velocidade de sedimentação (80mm. Internado por suspeita de síndrome de Sweet, para estudo etiológico e controlo de sintomas. Electroforese proteínas normal. Resultado histológico da biópsia de pele revelou infiltrado inflamatório neutrofílico difuso cutâneo compatíveis com síndrome de Sweet. Iniciou tratamento com prednisolona 20 mg, com melhoria 72h após o início de corticoterapia. Diagnóstico final: Síndrome de Sweet Clássico/Idiopático. Conclusão: Os autores pretendem descrever um síndrome incomum, muitas vezes no contexto de infecções ou exposição a fármacos. No entanto, salienta-se a associação frequente com patologia neoplásica, pelo que se deve

  8. Calidad y madurez de la uchuva (Physalis peruviana l. en relación con la coloración del fruto

    Directory of Open Access Journals (Sweden)

    Fischer Gerhard

    1999-12-01

    ="font-size: 12.0pt; font-family: ";Times New Roman";,";serif";;"> 

    Palabras claves: Desarrollo del fruto, carotenoides, Índice de madurez, acido ascórbico, provitamina A.

  9. ADN DE LA INNOVACIÓN - DE FACTORES CLAVES DE INNOVACION EN 21 EMPRESAS DEL SECTOR AGROINDUSTRIAL DNA DA INOVAÇÃO - FATORES CHAVE PARA INOVAÇÃO EM 21 EMPRESAS AGROINDUSTRIAL ADN OF INNOVATION - KEY FACTORS FOR INNOVATION IN 21 COMPANIES AGROINDUSTRIAL

    Directory of Open Access Journals (Sweden)

    JOSÉ G MEDINA H

    2012-12-01

    Full Text Available Este artículo identifica en una muestra de 21 empresas del sector agroindustrial del departamento de Antioquia - Colombia factores claves de innovación, que establecen una relación con los conceptos básicos de la estructura del acido desoxirribonucleico (ADN, con el fin de ayudar a las empresas a gestionar su estructura para la innovación. Para el desarrollo de este estudio se tomaron las variables definidas por el perfil innovador de la Metodología de Gestión Tecnológica por Proyectos 'MGT', la cual describe un perfil de las empresas respecto a las cuatro dimensiones de innovación: producto, proceso, mercadeo y organización [1] definidas por la Organización para la Cooperación y Desarrollo Económico [2]. Posteriormente se construyó una base de datos con los resultados del perfil innovador de empresas del sector agroindustrial obtenidos de la herramienta MGT; por último se implementó la herramienta estadística de análisis multivariable la cual permitió definir los factores claves de innovación más frecuentes e importantes de las empresas a las cuales se les aplicó la metodología 'MGT'[3].Este artigo identifica uma amostra de 21 empresas no setor de agronegócios do departamento de Antioquia - Colômbia fatores-chave da inovação, em seguida, estabelecer uma relação com o básico da estrutura do ácido desoxirribonucléico (ADN, a fim de ajudar as empresas estrutura para gerir a inovação. Para o desenvolvimento deste estudo foram tomadas pelo perfil de variáveis definidas Metodologia de Gestão de Projetos Inovadores de Tecnologia 'MGT', que descreve um perfil das empresas em relação as quatro dimensões da inovação: produto, processo, marketing e organização [1] definida pela Organização para a Cooperação e Desenvolvimento Econômico [2]. Mais tarde, ele construiu um banco de dados com os resultados do perfil inovador de empresas do agronegócio se reuniram a partir da MGT, e finalmente implementou a

  10. Bioethanol production from corn stover residues. Process design and Life Cycle Assessment; Bioetanolo da resuidui della lavorazione del mais: process design e analisi del ciclo di vita

    Energy Technology Data Exchange (ETDEWEB)

    De Bari, I; Dinnino, G; Braccio, G [Dipartimento Tecnologie per l' Energia, Fonti Rinnovabili e Risparmio Energetico, ENEA, Centro Ricerche Trisaia, Matera (Italy)

    2008-07-01

    nel centro ENEA di Trisaia: il pretrattamento a base di steam explosion e l'idrolisi enzimatica. L'impianto modellato ha una capacita di 60kt/a (dimensionato su bacini di approvvigionamento realistici in Italia); la biomassa e pretrattata con processo di steam explosion acido-catalizzato; la cellulosa e l'emicellulosa sono idrolizzate e fermentate separatamente; gli enzimi sono prodotti in situ. L'obiettivo principale e stato la minimizzazione del consumo di acqua di rete, di enzimi e di energia. I risultati indicano che la produzione di 1 kg di etanolo (95.4% in peso) richiede 3.5 kg di biomassa su base secca e produce un surplus di energia fino a 740 Wh. L'obiettivo principale dell'analisi LCA e stata la valutazione di impatto ambientale dell'intero ciclo di vita dalla produzione del bioetanolo fino al suo utilizzo in miscele E10. Il Boustead Model e stato utilizzato per compilare l'inventario di ciclo di vita. I risultati ottenuti e discussi in questo rapporto risentono di alcune limitazioni dovute principalmente ai seguenti punti: alcune rese di processo sono state estrapolate sulla base di previsioni di sviluppo ottimistiche; il recupero di energia e vapore potrebbe essere inferiore a quello calcolato per le perdite nei sistemi reali; il riciclo di acqua potrebbe essere limitato dalla tolleranza del lievito all'accumulo di potenziali sostanze tossiche. Ciononostante, la dettagliata analisi di processo sviluppata nel rapporto ha la sua importanza: nel quantificare gli obiettivi critici (ancorche ambiziosi) ai quali puntare per rendere fattibile il processo integrato; nel guidare la scelta delle tecnologie piu appropriate per superare alcuni colli di bottiglia del processo.

  11. Características del hiperinsulinismo en la enfermedad coronaria

    Directory of Open Access Journals (Sweden)

    Oscar Manuel Alba Mendoza

    1994-04-01

    Full Text Available EI síndrome de resistencia a la Insulina- hiperinsulinemia (IRS ha sido descrito como predictor importante de enfermedad coronaria (EC cuya morbi-mortalidad ocupa el primer lugar en Colombia (30% de las muertes. Se realizó un estudio para caracterizar y definir el hiperinsulinismo con respecto a la EC, desde el punto de vista de discriminación diagnóstica adecuada; buscando ofrecer información útil como posible común denominador de diversas anomalías metabólicas  involucradas como factores de riesgo cardiovascular. Se estudiaron 89 sujetos de uno y otro sexo con EC documentada angiográficamente (obstrucción > 70 %, sin: diabetes mellitus no insulino dependiente (DMNID, hiperlipidemias secundarias; enfermedades y medicamentos que interfieran el metabolismo lipidieo. Se estudiaron 74 sujetos sanos con tolerancia al ejercicio y electrocardiogramas (EKG 's normales; algunos con angiografía normal; que sirvieron como grupo control y que reunieron las mismas características de edad y sexo de los pacientes con EC. Se recogió información sobre variables demográficas; historia clínica y familiar; examen físico; variables antropométricas; presión arterial (PA; perfil Iipidico; acido úrico y glicemia e insulinemias basales y post-carga oral de 75 gr de glucosa a los 30, 60 Y 120 minutos. Se definió la hiperinsulinemia como un valor mayor de 40 uUI / mL; acorde con el punta de corte con mas alta sensibilidad (83% y especificidad (86% en una curva de las características operativas del receptor (curva ROC para valores de insulina de dos horas postcarga oral de glucosa. EI promedio de edad fue 51 ± 9 (SD (desviación estándar con intervalo de 32 a 74 años; 74% fueron hombres. Se muestran los valores promedios (±SEM de las distintas variables de los sujetos normoinsulinémicos vs. hiperinsulinémicos con su respectiva significancia estadística, después de ajuste por edad, sexo e índice de masa corporal (IMC. EI grado de respuesta

  12. Búsqueda y selección de una proteasa fúngica con potencial aplicación en la restauración de documentos históricos en el Archivo de Bogotá

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Cruz Ramírez

    2012-01-01

    Full Text Available Título en ingles: Screening for a fungal protease with potential in the biorestoration of historical valuable documents in Bogota Archive Resumen: Se ha buscado y seleccionado sistemáticamente una proteasa que pudiese ser usada en la eliminación “limpia” de encolantes sobre soportes documentales con valor de patrimonio histórico de forma eficiente y económica, a partir de la colección de hongos filamentosos del Archivo de Bogotá. De 74 morfotipos viables evaluados sobre placas selectivas, 32 morfotipos presentaron formación de halos de hidrólisis evidentes sobre placas diferenciales. De ellos, se evaluó el perfil isoenzimático de 8 morfotipos provenientes de muestreos documentales directos y de 2 morfotipos proteolíticos promisorios provenientes de un trabajo previo. Los 10 morfotipos seleccionados fueron representativos de los géneros Penicillium, Stachybotrys, Chaetomium, y Eladia. Luego de inducir la producción de proteasas extracelulares en medios líquidos diferenciales bajo tres fases de fermentación, se realizaron isoelectroénfoques analíticos tendientes a la observación de isoformas en el gradiente de pH establecido (3.0-10.0. Solo los morfotipos 8D (Chaetomium sp. y 21D (Eladia saccula presentaron una isoforma alcalina extrema, de puntos isoeléctricos 8.5 y 8.8, respectivamente, susceptible de selección con miras a su purificación y caracterización parcial de forma económica y eficiente. Los demás morfotipos, representativos de los géneros Penicillium sp., y Stachybotrys sp., presentaron unicamente isoformas proteolíticas en el rango acido de pH con puntos isoeléctricos que oscilan entre 4.0 y 5.0. Palabras clave: biodeterioro; hongo filamentoso; proteasa; halo de hidrólisis; punto isoeléctrico. Abstract: Studies on a protease as an efficient, environmental friendly and relatively economical remover of residual proteins for historical valuable documents were performed and was selected for this work, from

  13. Performance of a small stand alone photovoltaic-wind system at El Oyameyo D.F., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Juarez, A.; Campos, J. [Centro de Investigacion en Energia, UNAM, Mexico, D. F. (Mexico); Tiburcio Silver, A. [Instituto Tecnologico de Toluca-Division de Posgrado, Toluca (Mexico)

    1997-12-31

    hibrido fotovoltaico-viento. La potencia electrica instalada para los sistemas FV autocontenidos estan en el rango de 48 W-p hasta 768 W-p. Entre estos hay 4 sistemas FV que estan configurados en sistemas regulados de CD y otros 6 son sistemas regulados de CA. Todos estos sistemas utilizan bancos de baterias de plomo-acido (selladas o ventiladas) para almacenar la energia producida diariamente por los sistemas. El sistema hibrido FV-Viento esta formado actualmente por un aerogenerador de 5.0 Kw, un arreglo FV de 768 W-p, un banco de baterias de almacenamiento de 37.8 Kw-h y un inversor de DC/AC de 5.0 Kw. En este articulo se reporta la electricidad generada, el patron de carga y el comportamiento general del sistema hibrido fotovoltaico-viento. Se presentan tambien las caracteristicas tecnicas, las pruebas de energia del sistema hibrido y la experiencia obtenida del manejo de la energia y del mantenimiento del sistema para todos los sistemas. Se encontro que todos los sistemas habian demostrado buen desempeno a satisfaccion del usuario.

  14. Positron Scanning of Liver and Pancreas; Exploration de Foie et du Pancreas par les Positrons; Pozitronoskopiya pecheni i podzheludochnoj zhelezy; Exploracion del higado y del pancreas mediante positrones

    Energy Technology Data Exchange (ETDEWEB)

    Aronow, S; Thors, R; Brownell, G L [Physics Research Laboratory and Department of Surgery, Massachusetts General Hospital, Boston, MA (United States)

    1959-07-01

    para determinar el contorno del pancreas y del higado, respectivamente. Es singularmente dificil el problema de lograr una representacion visual del pancreas dado su reducido tamano y la presencia en su proximidad de organos de grandes dimensiones en los que el zinc se concentra. Los autores examinan diferentes procedimientos para abordar este problema. El cobre-64 en forma ionica sencilla y en forma de sal del acido etilendiaminotetra-acetico se concentra notablemente en el higado. Las exploraciones de ese organo mediante positrones parecen facilitar de modo considerable el diagnostico correcto de diferentes trastornos hepaticos. Los autores presentan datos sobre la distribucion de diferentes isotopos y compuestos en organismos animales. (author) [Russian] Uspeshnoe primenenie pozitronoskopi i v lokalizatsii mozgovykh opukholej vydvinulo ideyu o primenenii ehtogo tekhnicheskogo priema dlya analogichnykh tselej v lechenii drugikh organov. V obsledovaniyakh podzheludochno j zhelezy i pecheni ispol'zuyutsya sootvetstvenno Zn{sup 62} i Si{sup 64} v razlichnykh vida''. Vvidu obychno nebol'shogo razmera podzheludochno j zhelezy i nalichiya vblizi nee bol'shikh sosredotochivayushchi kh v sebe tsink organov problema obsledovaniya ee predstavlyaet osobye zatrudneniya. V dokumente rassmatrivayuts ya razlichnye sposoby resheniya ehtoj problemy. Kontsentratsiya v pecheni Si{sup 64} v prostom ionizirovanno m vide i v vide mednogo versenata dostigaet znachitel'nykh razmerov. Pozitronoskopi ya pecheni veroyatno pozvolit uspeshno provodit' diagnostiku razlichnykh narushenij deyatel'nosti pecheni. V dokumente privodyatsya dannye o raspredeleni i razlichnykh izotopov i khimicheskikh soedinenij v zhivykh organizmakh. (author)

  15. Búsqueda y selección de una proteasa fúngica con potencial aplicación en la restauración de documentos históricos en el Archivo de Bogotá

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Cruz Ramírez

    2012-08-01

    Full Text Available Normal 0 21 false false false ES-CO X-NONE X-NONE MicrosoftInternetExplorer4 Título en ingles: Screening for a fungal protease with potential in the biorestoration of historical valuable documents in Bogota Archive Resumen: Se ha buscado y seleccionado sistemáticamente una proteasa que pudiese ser usada en la eliminación “limpia” de encolantes sobre soportes documentales con valor de patrimonio histórico de forma eficiente y económica, a partir de la colección de hongos filamentosos del Archivo de Bogotá. De 74 morfotipos viables evaluados sobre placas selectivas, 32 morfotipos presentaron formación de halos de hidrólisis evidentes sobre placas diferenciales. De ellos, se evaluó el perfil isoenzimático de 8 morfotipos provenientes de muestreos documentales directos y de 2 morfotipos proteolíticos promisorios provenientes de un trabajo previo. Los 10 morfotipos seleccionados fueron representativos de los géneros Penicillium, Stachybotrys, Chaetomium, y Eladia. Luego de inducir la producción de proteasas extracelulares en medios líquidos diferenciales bajo tres fases de fermentación, se realizaron isoelectroénfoques analíticos tendientes a la observación de isoformas en el gradiente de pH establecido (3.0-10.0. Solo los morfotipos 8D (Chaetomium sp. y 21D (Eladia saccula presentaron una isoforma alcalina extrema, de puntos isoeléctricos 8.5 y 8.8, respectivamente, susceptible de selección con miras a su purificación y caracterización parcial de forma económica y eficiente. Los demás morfotipos, representativos de los géneros Penicillium sp., y Stachybotrys sp., presentaron unicamente isoformas proteolíticas en el rango acido de pH con puntos isoeléctricos que oscilan entre 4.0 y 5.0. Palabras clave: biodeterioro; hongo filamentoso; proteasa; halo de hidrólisis; punto isoeléctrico. Abstract: Studies on a protease as an efficient, environmental friendly and relatively economical remover of residual proteins for

  16. El aceite de pescado atenua las crisis convulsivas inducidas por hipertermia en ratas neonatas

    Directory of Open Access Journals (Sweden)

    Leopoldo E. Flores M.

    2008-01-01

    Full Text Available Un alto porcentaje (50-60% del cerebro en los mamíferos son principalmente grasas o lípidos, de éstos, el 35% son ácidos grasos esenciales, en particular los llamados omegas (O, como el Acido Docosahexanoico (DHA y el Eicosapentanoico (EPA llamados omega 3 (O-3. Diversos estudios han mostrado beneficios en la salud con la implementación de los O-3 como agentes terapéuticos en alteraciones cardiovasculares, renales, dérmicas, metabólicas, neurodegenerativas e inmunológicas. Evidencias experimentales sugieren un beneficio potencial del aceite de pescado (APE como neuroprotector debido al alto contenido de DHA y EPA. Sin embargo, es poco lo que se conoce en cuanto a los efectos que pudieran tener sobre alteraciones nerviosas, como las crisis convulsivas. En este contexto, se ha reportado que el tipo más común de trastorno epiléptico observado en los niños son las crisis convulsivas provocadas por fiebre (CF. La incidencia es de 3-5%, con ocurrencia entre los 5 meses y 5 años de edad, y se ha propuesto que esta alteración en la vida temprana pudiera tener efectos a largo plazo, manifestándose como un síndrome de epilepsia en la vida adulta. El objetivo del presente estudio fue evaluar el efecto del APE sobre las convulsiones inducidas por hipertermia experimental en un grupo de ratas Wistar macho de 5 días de edad (grupo SAPE cuyas madres consumieron una dieta base más un suplemento de APE (suministrado desde su infancia hasta la etapa de crianza. Este grupo se comparó con otro grupo de ratas de la misma edad y cepa (grupo SAPA cuyas madres consumieron una dieta base más un suplemento de aceite de palma (suministrado desde su infancia hasta la etapa de crianza, y con un tercer grupo de ratas (grupo CTRL cuyas madres consumieron la dieta base más agua bidestilada como suplemento. Las ratas tratadas con APE presentaron mayor resistencia a la elevación de la temperatura corporal inducida por la hipertermia, una menor frecuencia

  17. Synthesis of structured triacylglycerols containing medium-chain and long-chain fatty acids by interesterification with a stereoespecific lipase from Mucor miehei.

    Directory of Open Access Journals (Sweden)

    Nieto, Susana

    1999-06-01

    Full Text Available The preparation of structured triacylglycerols sn-1, sn-3 dilauryl, sn-2 eicosapentaenoyl glycerol and sn-1, sn-3 dilauryl, sn-2 docosahexaenoyl glycerol by enzymatic interesterification under restricted water availability is described. Laurie acid, one of the substrates for interesterification, was obtained by the controlled hydrolysis of coconut oil by a non-specific lipase obtained from Candida cylindracea. The fatty acid was separated from the hydrolysis products by silverresin column chromatography and converted to methyl ester, sn-2 Eicosapentaenoyl glycerol and sn-2 docosahexaenoyl glycerol were prepared by the hydrolysis of fish oil by the sn-1, sn-3 stereospecific immobilized lipase Lipozyme IM-20 obtained from Mucor miehei as described in the accompanying paper. The interesterification was carried out in a water jacketed glass reactor and the triacylglycerol products were separated and recovered through aluminum oxide column chromatography The interesterification procedure described allows to obtain In laboratory scale structured triacylglycerols containing medium-chain fatty acids at the sn-1 and sn-3 positions and long-chain polyunsaturated fatty acid from marine origin at the sn-2 glycerol position.

    Se describe la preparación de triacilgliceroles estructurados sn-1, sn-3 dilauril, sn-2 ecosapentaenoil glicerol y sn-1, sn-3 diiauril, sn-2 docosahexaenoil glicerol por interesterificación enzimática bajo disponibilidad de agua reducida. Acido láurico, uno de los sustratos para la interesterificación, se obtuvo mediante hidrólisis controlada del aceite de coco por una lipasa no-específica obtenida de Candida cylindracea. Los ácidos grasos se separaron de los productos de hidrólisis mediante cromatografía en columna de resina de plata y convertidos en sus esteres metílicos, sn-2 Eicosapentaenoil glicerol y sn-2 docosahexaenoil glicerol se prepararon mediante hidrólisis de aceite de pescado por la sn-1, sn

  18. Softwood forest thinning as a biomass source for ethanol production: A feasibility study for California

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, Kiran L; Wooley, Robert J; Aden, Andrew; Nguyen, Quang A; Yancey, Mark A; Ferraro, Francis M [Colorado(United States)

    2000-07-01

    hidrolisis de acido diluido de dos etapas para la produccion de etanol a partir de madera de coniferas, y la lignina residual se utiliza para generar vapor y electricidad. Para una planta que procesa 800 toneladas secas por dia de materia prima, el caso de una planta vecina es un concepto economicamente atractivo. El capital total estimado de inversion es de aproximadamente $70 millones en el caso de la instalada una junto a otra. La tasa interna de retorno resultante es de cerca del 24% utilizando un 25% de financiamiento equitativo. Por consiguiente, este tipo de planta de conversion de biomasa a etanol parece ser una proposicion atractiva para California, con el etanol reemplazando gradualmente al eter metil butil-terciario que esta destinado a desaparecer.

  19. Disposal of Waste into the Atmosphere; Elimination des Dechets Radioactifs dans l'Atmosphere; 0423 0414 0410 ; Evacuacion de Desechos Radiactivos en la Atmosfera

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, H. F. [Health Division, Los Alamos Scientific Laboratory, University of California, Los Alamos, NM (United States)

    1960-07-01

    en algunos aspectos la atmosfera puede compararse a la hidrosfera y a la litosfera como posible recipiente de desechos, la presencia de desechos radiactivos en suspension en el aire puede afectar de manera mas inmediata a la seguridad de la vida humana. La contaminacion de la atmosfera plantea dos problemas completamente distintos: 1) uno, de alcance limitado, que se circunscribe a la proximidad inmediata de una planta nuclear, y 2) otro mas universal y a largo plazo, debido a la extension de la contaminacion atmosferica. Los problemas de contaminacion de alcance limitado se vienen planteando desde hace muchos anos como consecuencia de la evacuacion de desechos no radiactivos tales como anhidrido sulfuroso, acido fluorhidrico y humos procedentes de la combustion del carbon. Sin embargo, los aspectos cientificos de este problema solo se empezaron a estudiar detenidamente en el curso de los ultimos anos. Las condiciones meteorologicas desempenan un papel importante en esta cuestion. En ciertos casos, las velocidades de descarga se han podido regular en funcion de las predicciones meteorologicas. No obstante, la solucion fundamental consiste aun en mantener las velocidades de descarga en los valores minimos posibles. (author) [Russian] S tochki zrenija udalenija othodov atmosferu mozhno sravnit' s gidrosferoj i litosferoj, no nalichie othodov v atmosfere imeet bolee neposredstvennoe otnoshenie k zhizni cheloveka. Sushhestvujut dve ochen' jasnye problemy, svjazannye s zagrjazneniem atmosfery: 1) zagrjaznenie atmosfery v neposredstvennoj blizosti ot ustanovki i 2) vsemirnaja problema izbezhanija dolgovremennogo i shirokogo zagrjaznenija vozduha. Problema zagrjaznenija vozduha v neznachitel'nyh masshtabah sushhestvuet mnogie gody, kak rezul'tat udalenija neradioaktivnyh othodov takih kak ugol'nyj dym, dvuokis' sery i ftoristye soedinenija vodoroda. Odnako jeta problema stala izuchat'sja tol'ko v poslednie gody. Meteorologicheskie uslovija igrajut vazhnuju rol' v jetoj

  20. Effet de la substitution du cuivre par du lithium sur les proprietes de l'oxyde spinelle lithium(x)cuivre(y-x)cobalt(3-y)oxygen(4) etudie pour l'electrocatalyse de la reaction de degagement de l'oxygene en milieu alcalin

    Science.gov (United States)

    Fatih, Khalid

    L'electrolyse de l'eau demeure la seule technologie industrielle de generation de l'hydrogene et de l'oxygene tres purs sans rejet de CO2 dans l'atmosphere, ce qui le rend tres attrayant par rapport a la combustion de carburants fossiles qui provoque presentement de serieux problemes environnementaux. Dans le but d'ameliorer le rendement de ce procede, nous avons developpe de nouveaux materiaux d'anode peu couteux, a base de l'oxyde mixte CuyCo3-yO 4, qui possedent une cinetique rapide pour la reaction de degagement de l'oxygene (RDO). Cette reaction suscite un interet particulier en raison de la surtension d'activation relativement elevee a l'anode qui cause la principale perte de rendement du procede. Une etude systematique a ete effectuee sur la substitution du Cu par du Li (0 a 40%), afin d'elucider les proprietes electrocatalytiques des oxydes LixCuy-xCo3-yO4. Ces oxydes, prepares sous forme de poudres par decomposition thermique des nitrates precurseurs entre 300 et 500°C, ont montre (DRX et FTIR) une structure spinelle inverse non-stcechiometrique avec une diminution du volume de la maille cristalline. La surface specifique par BET est d'environ 6 m2 g-1. Le pcn, obtenu par titrage acido-basique, a indique une diminution de la force du lien M-OH avec le taux du Li dans l'oxyde. Les analyses par XPS, realisees sur des films d'oxyde prepares par nebulisation reactive sur un substrat lisse de nickel, revelent un enrichissement de la surface en Cu a partir de 30% Li, et la presence des cations de surface Co2+, Co3+, Cu +, Cu2+ et Cu3+. La concentration de ce dernier montre un maximum a 10 et 20% Li. Suite a la substitution du Cu par du Li, la compensation de la charge serait assuree principalement par la formation d'especes Cu3+ pour les oxydes contenant jusqu'a 20% Li, et par la formation d'especes Co3+ aux taux de substitution superieurs. Les micrographies MEB montrent une morphologie hemispherique des particules d'oxyde reparties uniformement sur le substrat

  1. Assessing two different peroxidases´ potential for application in recalcitrant organic compound bioremediation Evaluación del potencial de dos peróxidas para su aplicación en biorremedación de compuestos orgánicos recalcitrantes

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    Torres Rodrigo

    2001-12-01

    (difenilamina, moléculas monoaromáticas tipo fenólicas (guayacol, y colorantes [(naranja de metilo y ABTS (2.2´ Azinabis (6- acido surfonic-3- etilbenzotinzolina]. Los sistemas de reacción estuvieron compuestos por mezclas monofásicas de agua: solvente orgánico miscible (metanol, etanol, isopropanol, acetonitrilo, tetrahidrofurano, dimetil sulfóxido, etc., sobre los cuales se evaluó la actividad catalítica de ambas peroxidasas. En la mayoría de los ensayos se observó actividad catalítica de las dos enzimas sobre los sustratos evaluados. Sin embargo, para el caso del naranja de metilo y algunos PAH's, la PPR no mostró capacidad de oxidación biocatalítica. A su vez, fue la enzima que mostró mayor tolerancia a los solventes evaluados, bajo los cuales vio mejorada apreciablemente su actividad cuando se emplearon sustratos de baja hidrofobicidad. Con los datos experimentales se calculó el kcat, como parámetro cinético, el cual sirvió para comparar el desempeño biocatalítico de cada enzima sobre los sustratos.

  2. Sarcoma de Kaposi: a propósito de un caso clínico, actualización del tema Kaposi 's sarcoma: a case report, update on the topic

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    Anadely Gámez Pérez

    2009-12-01

    Full Text Available El sarcoma de Kaposi (KS por sus siglas en inglés es una enfermedad similar al cáncer. Se relaciona con la infección del VIH, y se presenta en estadios avanzados de la enfermedad, afectando el 20% de las personas con VIH que no toman medicamentos antirretrovirales. En Pinar del Río existe una baja incidencia de infección por VIH/SIDA. Dada la infrecuencia del Sarcoma de Kaposi se presenta un caso. Paciente de 50 años de edad, que después de un cuadro de dolor en epigastrio comienza con lesiones en la piel similares a hematoma en resolución, con centro más oscuro y nodular, que toman prácticamente todo el cuerpo. El paciente presenta ligera pérdida de peso, pero no prurito, no fiebre, no lesiones en mucosa oral. Se determinó Hb: 112g/l Hto: 0.34l/l Leucocitos: 4.4x10(9/l. Se encontró aumento de células mononucleares en el diferencial con linfopenia asociada; velocidad de sedimentación, colesterol, transaminasas, función renal y proteínas totales, normales, pero trombocitopenia moderada, acido úrico elevado. En el aspirado medular aparece predominio de linfocitos atípicos, con depresión relativa de las series hematopoyéticas. Gastroscopia, negativa. Biopsia de piel: Compatible con Sarcoma de Kaposi. VIH: tres exámenes durante el estudio con tiempo de intervalo entre ellos 3 meses desde el inicio resultaron negativos. Último examen viral a los 7 meses de iniciado el estudio (positivo con Western Blot.Kaposi´s Sarcoma (KS is a cancer-like disease. It is most frequent related to HIV infection, present in late stages of the disease and affecting 20 % of HIV infected people having no Highly Active Antiretroviral Therapy (HAART. Since in Pinar del Rio Province a low incidence rate of HIV/AIDS is observed , Kaposi´s Sarcoma is very infrequent. A 50 year-old male who after presenting an epigastralgia suffers from hematoma-like skin lesions, in resolution and when palpated the darker center was nodular. These lesions take

  3. Acidosis y coma en el Diabético

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    Alfredo Jácome Roca

    1992-12-01

    Full Text Available

    Definición. La cetoacidosis diabética (CADy la alcohólica, la acidosis láctica y el síndrome hiperosmolar hiperglucémico (SHH a menudo se sobreponen en grado considerable, por lo que los revisaremos en conjunto. Definiremos la cetoacidosLs diabética como la descompensación grave de la diabetes, la emergencia endocrina más común caracterizada por un desequilibrio ácido-básico, de líquidos y electrolitos, asociado a una diuresis osmótica y catabolismo de las grasas por hiperglucemia insulino- deficiente.

    El síndrome hiperosmolar hiperglucémico es de comienzo lento y se caracteriza por trastorno del estado de conciencia, deshidratación profunda e hiperglucemia sin cetoacidosis. La cetoacidosLs alcohólica es un desequilibrio ácido-básico con deshidratación en alcohólicos, mujeres por lo común, no necesariamente diabéticas, aunque puede haber moderada hiperglucemia. La acidos Ls láctica puede ser complicación de un estado de shock y/o deshidratación severa, o de ingesta abundante de alcohol, lo que también puede llevar a hiperuricemia y gota.

    Signos y síntomas. Malestar general, astenia, anorexia, náusea, vómito, dolor abdominal con somnolencia, estupor y/o coma, pueden ser manifestaciones de cualquiera de las entidades arriba mencionadas.

    Sin embargo, aunque tanto en CADcomo en SHH hay signos de deshidratación (sequedad de mucosa con piel seca sin turgencia, ojos hundidos, en el primero hay náusea, vómito y respiración acidótica (rápida y profunda, lo que generalmente falta en el segundo. ElCADes de niños y adultos jóvenes o maduros, con función cardio-renal aceptable mientras que el SHHes más de ancianos, a menudo hipertensos con fallas renal o cardíaca, hemiparéticos, que pueden consultar por convulsiones focales. No siempre el paciente es reconocido como diabético, sobre todo en SHH.

    Lapoliuria y la polidipsia caracterizan a la acidosis diabética y al s

  4. Novel organic solvent-tolerant esterase isolated by metagenomics: insights into the lipase/esterase classification Nueva esterasa tolerante a los solventes orgánicos aislada por metagenómica: ideas sobre la clasificación de las esterasas/lipasas

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    Renaud Berlemont

    2013-03-01

    gen codificante de una hipotetica lipasa/esterasa. La secuencia deducida de amino acidos (RBest1 contiene los motivos conservados de enzimas lipoliticas y esta relacionada con la lipasa OST previamente descrita de Lysinibacillus sphaericus 205y, que es la unica enzima procariota estudiada perteneciente al subgrupo 4.4 de a/ß hidrolasas (abH4.04. Estudios in vivo e in vitro sobre la especificidad de sustratos de RBest1, utilizando triacil-gliceroles o p-nitrofenil-esteres, respectivamente, revelaron que la enzima es altamente especifica para compuestos butiricos (C4, comportandose como una esterasa y no como una lipasa. La esterasa RBest1 fue purificada y caracterizada bioquimicamente. La actividad optima de esterasa fue observada a pH 6,5 y las temperaturas optimas fueron entre 38 y 45 °C. Se establecio que la actividad enzimatica, determinada por hidrolisis de p-nitrofenil esteres, es afectada en presencia de diferentes solventes organicos miscibles y no miscibles, y tambien sales. Notoriamente, RBest1 permanece significativamente activa a elevadas fuerzas ionicas. Estos hallazgos sugieren que RBest1 posee la capacidad de las enzimas OST de la adaptacion molecular en presencia de compuestos organicos, asi como la resistencia de las proteinas halofilas.

  5. Oxygen reduction using platinum electrocatalysts prepared by liquid phase photo-deposition; Reduccion de oxigeno mediante electrocatalizadores de platino preparados por foto-deposicion en fase liquida

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Camacho, B.; Perez-Galindo, J. A.; Valenzuela, M. A.; Gonzalez-Huerta, R. G. [Instituto Politecnico Nacional, ESIQIE, Mexico D.F. (Mexico)]. E-mail: rosgonzalez_h@yahoo.com.mx

    2009-09-15

    This work presents the synthesis and characterization of nanometric-sized Pt/C electrochemical catalysts using impregnation and liquid phase photo-deposition methods. Two platinum precursors were used, C{sub 10}H{sub 14}O{sub 4}Pt (Pt acetylacetonate, Pt(acac){sub 2}) and H{sub 2}PtCl{sub 6} (hexachloroplatinic acid) to study the effect on the particle size and the electrocatalytic behavior in the oxygen reduction reaction. The characterization of the catalysts was done using x-ray diffraction, hydrogen chemisorption and transmission electron microscopy. The electrochemical study was conducted with cyclic voltamperometry and rotary disc electrode (RDE) techniques. Pt (E-tek) was used as a reference catalyst. The peaks of the platinum were identified based on the x-ray diffraction results, and correspond to crystalline phases (111) and (200), whose intensity was greater when using H{sub 2}PtCl{sub 6} versus Pt(acac){sub 2}. The hydrogen chemisorption and transmission electron microscopy tests found that the larger-sized particle (1-5 nm) and greater metallic dispersion was obtained using Pt(acac){sub 2} as a platinum precursor and liquid phase photo-deposition. It was also found that this material presented the best electrochemical response, showing a open-circuit potential of 0.96 V and over-potential of 0.05 V with respect to H{sub 2}PtCl{sub 6} and of 0.22 V with respect to the catalyst obtained using impregnation. [Spanish] En este trabajo se presenta la sintesis y caracterizacion electroquimica de catalizadores de tamano nanometrico de Pt/C empleando los metodos de impregnacion y foto-deposicion en fase liquida. Se utilizaron dos precursores del platino C{sub 10}H{sub 14}O{sub 4}Pt (acetil-acetonato de Pt, Pt(acac){sub 2}) y H2PtCl6 (acido hexacloroplatinico), para estudiar el efecto que tienen sobre el tamano de particula y el comportamiento electrocatalitico en la reaccion de reduccion de oxigeno. La caracterizacion de los catalizadores se realizo mediante

  6. Developments in the technology for the combustion of water emulsions in Mexican fuel oil; Desarrollos en la tecnologia para la combustion de emulsiones agua en combustoleo mexicano

    Energy Technology Data Exchange (ETDEWEB)

    Diego, Antonio Marin; Martinez Flores, Marco A.; Tamayo Flores, Gustavo; Alarcon Quiroz, Ernesto; Melendez Cervantes, Carlos [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2001-07-01

    The residual petroleum oil (fuel oil) is the most used fuel in boilers of electrical and industrial power stations. Nevertheless, the use of this fuel can generate diverse problems such as the elevated particle emissions, that affect the boiler efficiency, darken the visibility by the smoke that leaves the chimneys and is emitted to the Environment. In addition, sulfur trioxide is produced, which reacts with the water present in the combustion gases, forming sulfuric acid that, when emitted, also affects the visibility of the plume and can be condensed, originating corrosion and increased accumulation of deposits in the boilers. The experimental research was made in a comparative base, between combustion tests of fuel oil, with emulsions where the water concentration and the size of the drops of this one was varied. A diagram of the supply of fuel and preparation of emulsions in a pilot furnace is shown. The article contains graphs of the effect of the water concentration of the emulsions in the particulate emission. The article contains figures of the cenospheres produced by the fuel oil combustion (500 x) and the ones produced by the combustion with 5% of water (500 x). Also shows graphs of the effect of the water drop size of emulsions in the particulate emission, of the reduction of the sulfur trioxide with soluble magnesium products in the water of emulsions, and of the free particle acidity with neutralizers of water emulsions of soluble magnesium. [Spanish] El aceite residual de petroleo (combustoleo) es el combustible mas utilizado en calderas de centrales electricas e industriales. Sin embargo, el uso de este combustible puede generar diverso problemas como las emisiones elevadas de particulas, que afectan la eficiencia de una caldera, obscurecen la visibilidad pero el humo que sale de las chimeneas y se emiten al medio ambiente. Ademas se produce trioxido de azufre, el cual reacciona con el vapor de agua presente en los gases de combustion, formado acido

  7. Propagação vegetativa de cedo-australiano (Toona ciliata M. Roemer por miniestaquia Vegetative propagation of Toona ciliata M. Roemer by the minicutting technique

    Directory of Open Access Journals (Sweden)

    Jonicélia Cristina Araújo Vieira de Souza

    2009-04-01

    Full Text Available O método de propagação usual do cedro-australiano (Toona ciliata é via seminal, entretanto a oferta sazonal das sementes e sua curta viabilidade ao longo do tempo representam um problema para a produção contínua de mudas destinadas à implantação de povoamentos. Este trabalho foi conduzido com o objetivo de avaliar a viabilidade da propagação vegetativa da espécie por miniestaquia e a necessidade da aplicação de acido indolbutírico (AIB para o enraizamento das miniestacas. A partir de um banco de estacas de origem seminal, foram obtidas brotações para produção de mudas clonais, em três diferentes épocas de coleta (2,5; 4,5; e 5,5 meses após a recepa das mudas. Antes do estaqueamento, as miniestacas tiveram suas bases imersas em quatro concentrações de AIB (0; 1.500; 3.000; e 4.500 mg L-1. Durante o experimento, obtiveram-se 100% de sobrevivência das minicepas e das miniestacas. Houve 100% de enraizamento das miniestacas nas três coletas, não ocorrendo diferença no comprimento de raízes em função das doses de auxina aplicadas. Quanto maior o intervalo entre as coletas e quanto maiores as brotações que originaram as miniestacas, maior a velocidade de crescimento das mudas. Miniestacas de cedro-australiano possuem capacidade de enraizamento, e mudas recepadas apresentam brotação, possibilitando a clonagem da espécie pelo processo de miniestaquia.Sexual propagation is the method commonly used for the Australian Red Cedar Toona ciliata. However, seasonal seed availability and short viability are a concern for the continuous offer of seeds for implantation. The objectives of this study were to evaluate the viability of vegetative propagation of this species through minicutting and to test indolbutiric acid (IBA application for rooting of minicuttings. Sprouts for clonal minicutting production were obtained from a miniclonal garden established from seeds, in three different harvest times (2.5; 4.5 and 5.5 months

  8. Emergencia de la resistencia antibiótica debida a las β-lactamasas de espectro extendido (BLEE: detección, impacto clínico y epidemiología Emergence of antimicrobial resistance to extended-spectrum β-lactamases (ESBL: detection, clinic impact and epidemiology

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    SALIM< MÁTTAR

    2007-03-01

    Full Text Available RESUMEN La rápida emergencia de la resistencia antimicrobiana debida a las BLEE tiene un impacto significativo en la salud pública. En los últimos 24 años ha suscitado un gran interés el conocimiento acerca de las BLEE, esta explosión de publicaciones abarca a todos los continentes y más de 30 países, actualmente es motivo de preocupación y se considera un problema de salud pública. Las BLEE son enzimas que producen los gram negativos y confieren resistencia a las penicilinas, a todas las cefalosporinas y al aztreonam, pero no a los carbapenems ni a las cefamicinas y la mayoría son inhibidas por el acido clavulanico. En general las BLEE son derivadas de TEM-1, TEM-2 y SHV-1, difieren entre si de sus progenitoras por unos escasos aminoácidos por lo que su filogenia es cercana. Son comúnmente encontradas en E.coli, Klebsiella sp, y P.mirabilis, no obstante, existen otras BLEE que difieren filogenéticamente de TEM y SHV, como las CTX-M, las carbapenemasas tipo OXA y las metalo-β-lactamasas VIM e IMP, típicamente encontradas en especies de P. aeruginosa, Serratia sp and Enterobacter sp. La producción de BLEE en los patógenos de importancia clínica es un problema serio en los pacientes hospitalizados debido a las implicaciones clínicas, terapéuticas y económicas. Las técnicas para la detección de las BLEE van de lo simple con aspectos fenotipicos hasta las pruebas complejas moleculares de geno-detección específica. El objetivo de esta revisión es discutir el impacto clínico y epidemiológico de las BLEE más prevalentes así como las técnicas para su detección y su seguimiento nosocomial.ABSTRACT The rapid emerge of antimicrobial resistance dueto ESBL has a significant impact in public health. In the last 24 years, the study of extendedspectrumβ-lactamases (ESBL has created great interest. This has been documented by publications from all continents and more than 30 countries, and the extent of this problem is a public

  9. Estudos sobre o xanthoma: biochimica e pathogenia Studies in xanthoma: biochemistry and pathogenesis

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    Gilberto G. Villela

    1935-12-01

    Full Text Available 1. No presente trabalho são descriptos dois casos de xanthelasmatose (xanthoma com perturbações accentuadas do metabolismo dos lipides e esteroes. 2. Um dos casos apresentou notavel cholesteroluria não mostrando o doente lesões renaes, ao passo que o outro caso sendo portador de pyelonephrite não eliminava cholesterol. 3. Foram feitas dosagens de cholesterol, acidos graxos totaes e lecithina, no sangue, urina e tumores, obtendo-se valores muito elevados. As demais provas (histo-chimicas, polarização microscopica confirmaram a presença de abundante infiltração de lipides e cholesterol nos tecidos. 4. A prova de carga de Bürger feita no caso I demonstrou diminuição da tolerancia para o cholesterol. 5. A therapeutica insulinica fez baixar o cholesterol e a glycose do sangue sem, comtudo, offerecer melhora clinica do paciente. No caso II houve baixa da cholesterolemia e da glycemia com desapparecimento dos tumores, evidenciando a diversidade das formas clinicas destes casos. 6. A intradermo-reacção feita com o cholesterol no caso I produziu reacção positiva, suggerindo um estado de hypensensibilidade para as substancias de infiltração no xanthelasma (xanthoma. 7. Os aspectos clinico-morphologicos dos casos estudados indicam tambem a ocorrencia de processos de sensibilisação cutanea. 8. As lipidoses são encaradas neste trabalho como toxicodermias hematogenicas, sendo proposto para seu estudo os mesmos methodos de exploração cutanea.1. In the present paper two cases of xanthelasmatosis (xanthoma with marked changes in lipid and sterol metabolism are studied. 2. One of the cases without injuries shows accentuated cholester-oluria, while the other with renal injuries presented pyelonephritis without cholesteroluria. 3. Cholesterol, total fatty acids and lecithine give high values in both cases. Histo-chemical and polariscopic researches confirmed a real infiltration of cholesterol and lipids in tissues. 4. Burger's test in case

  10. Avaliação do desempenho de frangos de corte alimentados com rações contendo probiótico e diferentes níveis de nucleotídeos

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    João Batista Canevari Bruno

    2012-02-01

    Full Text Available O objetivo deste trabalho foi avaliar o desempenho de frangos de corte alimentados com ração contendo um probiótico comercial e diferentes níveis de nucleotídeos. Foram utilizados 1050 pintos de 01 dia, machos da linhagem Ross 308 totalizando trinta e cinco aves por boxe, em um delineamento inteiramente casualizado com cinco repetições por tratamento. As aves foram criadas até 42 dias de idade, e receberam as rações experimentais a base de milho e farelo de soja contendo 6 níveis de nucleotídeos (0; 100; 200; 300; 400 e 500 gramas por tonelada de ração. Os nucleotídeos foram utilizados na fase inicial (1 a 21 dias e fase de crescimento (22 a 35 dias. Durante a fase final (36 a 42 dias os nucleotídeos foram removidos da ração . Houve melhora linear no desempenho dos frangos no período de 1 a 21 dias, indicando que, quanto maior o nível de nucleotídeos na dieta, maior o peso corporal das aves. A conversão alimentar também melhorou linearmente nesse período à medida que aumentou o nível de nucleotídeos na ração. O peso no período de 35 dias, também teve um comportamento linear, semelhante ao período de 1 a 21 dias, indicando que, o nível de nucleotídeos na ração melhorou o desempenho. A concentração plasmática de acido úrico demonstrou efeito quadrático no período de 1 a 21 dias, indicando 231,59 gramas de nucleotídeos por tonelada de ração, como o melhor, em níveis mínimos de ácido úrico, por outro lado, no período de 35 dias de idade, estimou-se o nível de 208,99 g de nucleotídeos por tonelada de ração; como o melhor em níveis mínimos de ácido úrico no sangue. No período final (35 a 42 dias e período total (1 a 42 dias de idade não foi possível o observar efeito dos contrastes testados neste trabalho.

  11. Nefrolitiasis de infección: caso clínico Nephrolithiasis of infection: clinical case

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    Nadienka Rodríguez Ramos

    2010-03-01

    Full Text Available Se presenta un caso de litiasis de infección, conocida con el nombre de cálculos de estruvita y asociado a una enfermedad metabólica subyacente y diabetes mellitus tipo 2 de reciente debut, el cual se manifestó con oliguria e infección, como resultado de una obstrucción urinaria bilateral parcial. El paciente de 48 años de edad, con antecedentes de cardiopatía isquémica, hipertensión arterial y de expulsar cálculos de riñón, consultó su caso el 21 de enero de 2009. Manejaba cifras de creatinina, glicemia y acido úrico normales anterior al ingreso y estas tuvieron un comportamiento ascendente durante la obstrucción, excepto el ácido úrico. En el diagnóstico aportaron datos de interés la ecografía renal y de próstata, la Uro-TAC y gammagrafía renal con MAG-3. El diagnóstico diferencial incluyó toda causa extrínseca e intrínseca, esta última relacionada con cálculos, coágulos o papila renal necrosada, que provocaran alteración al libre flujo urinario. Se estableció como patrones de buena evolución, la recuperación del volumen urinario, la normalización de la glucemia y creatinina, así como la permanencia del urocultivo negativo. El manejo terapéutico motivó a la utilización de la nefrolitotomía percútanea como una de las opciones que ofrecen los procederes endorulógicos, además del control de las enfermedades de base, lo que resultó una favorable evolución del caso.A clinical case of lithiasis of infection is presented, known as calculi of struvite associated to an underlying metabolic disease and diabetes mellitus type-2 of recent onset, with oliguria and infection as a result of a partial bilateral urinary infection. A 48 years-old patient having medical records of ischemic heart disease, hypertension and expulsion of kidney stones attended to the office in January 21, 2009 presenting normal values of creatinine, glycemia and uric acid before the admission; these values increased during the obstruction

  12. Níveis de substituição da DL-metionina pela metionina hidróxi análoga em base equimolar, em dietas para frangos de corte Levels of substitution of Dl-methionine by methionine hidroxy analogue in basis equimolar in broilers diets

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    Paulo Visentini

    2005-12-01

    Full Text Available Este trabalho objetivou testar o efeito de níveis de substituição da DL-Metionina (DL-Met por Metionina Hidróxi Análoga acido livre (MHA-FA como fonte do aminoácido metionina para frangos de corte de 1 a 44 dias de idade. Foram utilizados 700 pintos de corte de um dia de idade, machos, da linhagem Ross. O delineamento experimental foi em blocos para evitar o efeito ambiental, constituído de cinco tratamentos com sete repetições de 20 aves.Substituiu-se em base equimolar a DL-Met por MHA-FA (0, 25, 50, 75 e 100%. As dietas foram isonutritivas para todos os tratamentos diferindo apenas quanto à fonte de metionina e equivalência utilizada. Os parâmetros avaliados foram: consumo alimentar, peso corporal, conversão alimentar, empenamento, gordura abdominal, rendimento de carcaça e peso de fígado. Não foram encontradas diferenças significativas (P>0,05 entre as fontes de metionina estudadas, exceto para empenamento que foi inferior quando se utilizou a MHA-FA. Com base nos resultados encontrados, conclui-se que a DL-Metionina e a MHA-FA suplementadas em base equimolar, não modificam o desempenho zootécnico de frangos de corte de 1 a 44 dias de idade.The objective of this work was to study the effects of substitution of DL-Methionine (DL-Met by Methionine Hidroxi Analogue free acid (MHA-FAin on equimolar basis, at different levels, as source of Methionine for broilers, from 1 to 44 days. Seven hundred male one day old chicks (ROSS, were used. The experimental design was in BLOCKs, to avoid ambiental effects, chicks were randomly distributed in five treatments with seven replicates of twenty birds each. The constitution of treatments was based on the substitution of DL-Met by MHA-FA in equimolar basis (0;25; 50; 75 and 100%. Diets were isonutritives for all treatments, differing only in respect to the source of Methionine. The parameters evaluated in this study were: body weight, feed consumption, feathering, abdominal fat pad

  13. Search for alkaloids on callus culture of Passiflora alata

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    Michelli Wesz Machado

    2010-08-01

    para germinação apos assepsia, e a formação de calo foi iniciada em meio MS com quantidades adequadas de fitohormonios, previamente determinadas. Sessenta dias após a inoculação os calos foram repicados para meio semi-solido com e sem L-triptofano (50, 100, 200 mg/L, mantidos por 90 dias em condições padrão. Amostras foram coletadas com 6, 16, 26, 36, e 90 dias, realizada extração acido-base e o extrato analisado por CLAE. Os resultados mostraram a ausência de harmana, harmina, harmol, harmalol e harmalina. Dois picos presentes nas amostras com L-triptofano foram coletados e analisados através de espectrometria de massas, electrospray modo positiva [ESI(+-MS] e analise em tandem ESI(+-MS/MS. Os espectros correspondentes foram similares, mostrando a perda consecutiva de 68 Da, atribuídos ao pirazol. Este fato aponta para uma transformação não enzimática, não relacionada a uma biossintese previamente descrita para alcalóides β-carbolínicos.

  14. Electrochemical study of oxygen reduction reaction in Pt/C catalysts synthesized by photo-deposition; Estudio electroquimico de la reaccion de reduccion de oxigeno en catalizadores de Pt/C sintetizados por fotodeposito

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Galindo, J. A.; Ruiz-Camacho, B.; Valenzuela-Zapata, M. A.; Gonzalez-Huerta, R. G. [IPN, ESIQIE, Mexico, D.F. (Mexico)]. E-mail: rosgonzalez_h@yahoo.com.mx

    2009-09-15

    interaccion entre estos dos componentes ha recibido mucha atencion en los ultimos anos. Esta interaccion es considerada como la responsable en los efectos de crecimiento de la estructura y la disminucion de la dispersion de las particulas del metal sobre el soporte, provocando un bajo desempeno global y un menor tiempo de vida util de la pila. Las propiedades del soporte se ven acentuadas en los catalizadores catodicos, donde se lleva a cabo la reaccion de reduccion de oxigeno por las condiciones de operacion que se tienen, actualmente se estan investigando sintesis que mejoren la interaccion metal-soporte y asi aumentar el tiempo de vida de la pila de combustible. En este trabajo se presenta el estudio electroquimico de catalizadores de tamano nanometrico de platino soportado en carbon (Pt/C) sintetizados por el metodo de Foto-deposito Quimico para determinar su efecto catalitico y estabilidad en la reaccion de reduccion de oxigeno en medio acido. Se utilizo como precursor de platino el C{sub 10}H{sub 14}O{sub 4}Pt (Pt(acac)2). El estudio electroquimico se realizo con las tecnicas de voltamperometria ciclica y electrodo de disco rotatorio observando que los catalizadores sintetizados presentan un comportamiento similar al Pt ETek. El estudio cinetico mostro un potencial a circuito abierto de 0.96 V, con una pendiente de Tafel de 73 mV dec-1 y a una corriente de 0.1 mA cm-2 se tiene un potencial de 0.91 V. Los autores agradecen el apoyo al ICYTDF (proyecto PICS08-37) y al IPN (Proyecto SIP-20090433).

  15. Ground level chemical analysis of air transported from the 1998 Mexican-central american fires to the southwestern USA

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva Fierro, Ignacio [Departmento de Ciencias Ambientales, COFAA, CIIDIR-IPN Unidad Durango, Durango, Durango (Mexico)]. E-mail: ifierro62@yahoo.com; Popp, Carl J. [Department of Chemistry, New Mexico Tech, NM (United States); Dixon, Roy W. [Department of Chemistry, California State University at Sacramento, Sacramento, CA (USA); Martin, Randal S. [Department of Civil and Environmental Engineering, Utah State University, Logan, UT (United States); Gaffney, Jeffrey S. [Department of Chemistry, University of Arkansas at Little Rock, Little Rock, AR(United States); Marley, Nancy A. [Graduate Institute of Technology, University of Arkansas at Little Rock, Little Rock, AR (United States); Harris, Joyce M. [Office of Oceanic and Atmospheric Research, ERL/CMDL, NOAA, Boulder, CO (United States)

    2009-02-15

    km desde la fuente de los incendios. Las mediciones de varios marcadores quimicos fueron tomadas antes y durante la incursion del humo en Socorro, NM. Dias antes de que llegara la contaminacion a NM, grandes areas de Texas, Louisiana y la parte baja del valle del Rio Mississippi fueron cubiertas por el humo de los incendios. La suma de compuestos carbonilicos vario, antes del humo de 5.6 ppbv, a 15.5 ppbv durante la incursion del humo; la suma de acidos carboxilicos vario de 7.2 ppbv a 8.6 ppbv; los hidrocarburos con 1 y 2 carbonos de 270 ppbv a 133 ppbv; los NO{sub 3}{sup -} en particulas de 0.1 a 1.3 {mu}g/m{sup 3}; los SO{sub 4}{sup -2} variaron de 1.2 a 3.4 {mu}g/m{sup 3}; las PM10 se mantuvieron en el intervalo de antes de la incursion (15-20 {mu}g/m{sup 3}). Los resultados indican un impacto significativo en un sitio rural del transporte de larga distancia de contaminantes de humo primarios y secundarios provenientes de eventos de quema de biomasa y la importancia de estas especies se debe principalmente al intervalo de tamano gaseoso y de aerosol fino. Estos aerosoles finos son importantes como agentes coadyuvantes al cambio climatico y afectan la calidad del aire y visibilidad.

  16. Caracterização e extração de compostos voláteis de resíduos do processamento de maracujá (Passiflora edulis Sims f. flavicarpa degener Characterization and extraction of volatile compounds from passion fruit (Passiflora edulis Sims f. flavicarpa degener processing waste

    Directory of Open Access Journals (Sweden)

    Lília Calheiros de Oliveira

    2012-12-01

    Full Text Available Este estudo objetivou extrair e identificar compostos voláteis presentes nos resíduos de processo de maracujá. Obtiveram-se destilados a partir de resíduos de maracujá através das técnicas de hidrodestilação simples e hidrodestilação com arraste de gás nitrogênio. Os compostos voláteis presentes nos destilados foram capturados por microextração em fase sólida, empregando-se fibra Carboxen/DVB/DMS, e identificados por cromatografia gasosa acoplada com espectrômetro de massa, usando a coluna capilar de sílica fundida CP WAX 52. Foram identificados trinta e um compostos voláteis no extrato obtido pela técnica de hidrodestilação simples, sendo os principais compostos: neral (26,19%, cinamato de metila (18,52%, linalol (16,82%, 1-undecanol (5,60%, cis-óxido de linalol (4,41%, benzaldeído (3,92% e 1-hexanol (3,48%. Para a hidrodestilação com arraste de gás nitrogênio, trinta compostos foram identificados, sendo que, em maior porcentagem de área, destacaram-se: cinamato de metila (30,41%, neral (24,46%, β-ionona (13,81%, linalol (4,0% e acido butanoico (2,19%. O presente estudo revelou que os resíduos de maracujá apresentam compostos voláteis que podem ser extraídos na forma de aromas, apresentando potencial para gerar essências naturais com valor agregado.The aim of this study was to extract and identify volatile compounds from passion fruit residues generated during processing. Distillates of passion fruit residues were obtained from the techniques of simple hydrodistillation and hydrodistillation by passing nitrogen gas. The volatile compounds present in the distillates were captured by solid phase microextraction with Carboxen/DVB/DMS fiber. The volatile compounds were indentified by gas chromatography with mass spectrometry using a fused sillica capillary column with a CP WAX 52 stationary phase. Thirty one compounds were indentified by simple hydrodistillation technique. The main compounds were: neral (26

  17. Rhizosphere competent Mesorhizobiumloti MP6 induces root hair curling, inhibits Sclerotinia sclerotiorum and enhances growth of Indian mustard (Brassica campestris Mesorhizobium loti MP6 rizosférico competente induz encurvamento do pelo daraiz, inibe Sclerotinia sclerotiorum e estimula o crescimento de mostarda indiana (Brassica campestris

    Directory of Open Access Journals (Sweden)

    Shikha Chandra

    2007-03-01

    Full Text Available The bacterial strain Mesorhizobium loti MP6, isolated from root nodules of Mimosa pudica induced growth and yield of Brassica campestris. The isolate MP6 secreted hydroxamate type siderophore in Chrom-Azurol Siderophore (CAS agar medium. Production of hydrocyanic acid (HCN, indole acetic acid (IAA and phosphate solubilizing ability was also recorded under normal growth conditions. Root hair curling was observed through simple glass-slide technique. In vitro study showed a significant increase in population of M. loti MP6 in rhizosphere due to root exudates of B. campestris. In dual culture technique the strain showed a strong antagonistic effect against Sclerotinia sclerotiorum, a white rot pathogen of Brassica campestris. The growth of S. sclerotiorum was inhibited by 75% after prolonged incubation. Efficient root colonization of mustard seedlings was confirmed by using a streptomycin-resistant marker M. loti MP6strep+. The M. loti MP6 coated seeds proved enhanced seed germination, early vegetative growth and grain yield as compared to control. Also, a drastic decline (99% in the incidence of white rot was observed due to application of M. loti MP6.A cepa bacteriana Mesorhizobium loti MP6 isolada de nódulos de raiz de Mimosa pudica induziu o crescimento e o rendimento de Brassica campestris. A cepa MP6 secretou sideróforo do tipo hidroxamato em meio sólido Chrom-Azurol Siderophore (CAS. Em condições normais de crescimento, a cepa foi também capaz de produzir de ácido cianídrico (HCN e acido indolacético (AIA e solubilizar fosfato. O encurvamento do pelo da raiz foi observado usando a simples técnica de lâmina e lamínula. Estudos in vitro mostraram um aumento significativo na população de M. loti MP6 na rizosfera devido aos exsudatos de B. campestris. Empregando-se técnica de co-cultura, a cepa mostrou um grande efeito antagônico contra o fungo Sclerotinia sclerotiorum, o patógeno da podridão branca de Brassica campestris. Ap

  18. Influência do método de síntese no processo de pilarização com titânio de uma esmectita da região amazônica Influence of the synthesis method on the process of pillarization of smectite from the amazonic region with titanium

    Directory of Open Access Journals (Sweden)

    D. L. Guerra

    2006-12-01

    Full Text Available Amostras de argila esmectítica provenientes do município de Serra Madureira no Estado do Acre foram utilizadas no processo de pilarização. As matrizes natural e pilarizada foram caracterizadas por difração de raios X, espectroscopia no infravermelho com transformada de Fourier, análises térmicas diferencial e gravimétrica, microscopia eletrônica de varredura, espectroscopia de raios X por energia dispersiva e análise textural. As soluções pilarizantes de titânio, Ti(OC2H54 e TiCl4, foram analisadas por espectroscopia no infravermelho com transformada de Fourier. O íon intercalante foi obtido através da reação química entre as soluções de Ti(OC2H54 e HCl na proporção aproximada de HCl/Ti=1 e soluções de TiCl4 em reação com etanol com relação Ti/argila= 25 mmol Ti/g. A intercalação da notronita foi efetuada utilizando-se de dois métodos: com a solução de acido clorídrico incorporada paulatinamente na solução de etóxido de titânio, e utilizando o cloreto de titânio em solução de etanol, com vigorosa agitação a 25 ºC durante 3 h e com calcinação a 450 ºC e 600 ºC. Os resultados de difração de raios X do processo de pilarização mostraram alterações no espaçamento basal de 15,30 Å para 18,76 Å, e na área de superfície específica de 44,37 m²/g para 188,72 m²/g. A estabilidade térmica da argila natural foi otimizada com o processo de pilarização.Smectite clays of the State of Acre, Brazil, were used for the pillarization process. The natural and pillarized matrices were characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR, thermal analysis, scanning electron microscopy, energy dispersive spectroscopy and textural analysis. The titanium pillarized solutions Ti(OC2H54 and TiCl4 were analyzed by FTIR. The intercalation ion was obtained by reacting Ti(OC2H54 with HCl (HCl/Ti ~ 1 and TiCl4 with ethanol (Ti/clay ~ 25 mmol Ti/g. The notronite intercalation was

  19. Evolution of the geothermal system in Acoculco, Pue., Mexico: Study based on petrography of well EAC-2 and other information; Evolucion del sistema geotermico de Acoculco, Pue., Mexico: un estudio con base en estudios petrograficos del pozo EAC-2 y en otras consideraciones

    Energy Technology Data Exchange (ETDEWEB)

    Viggiano Guerra, Julio Cesar [Universidad Michoacana de San Nicolas de Hidalgo, Michoacan (Mexico)]. E-mail: cesar.viggiano@live.com; Flores Armenta, Magaly; Ramirez Silva, German R. [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)

    2011-01-15

    Acoculco, Pue., geothermal area is located 180 km away from Mexico City. It includes two hydrothermally altered areas with acid sulfate cold springs and some mofettes, associated with a complex structural framework presented in an area 2000 m thick of Tertiary-Quaternary volcanic rocks, Cretaceous metamorphized limestone and even Cretaceous granite. The field seems to resemble kaipohan type geothermal fields. Two exploratory wells have been drilled in the area. In 1995, well EAC-1 was drilled to a depth of 1810 m and in 2008 well EAC-2 was drilled to a depth of 1900 m. We discuss results and interpretations of petrographic studies made on the second well, and how some information from the first well is used to interpret the evolution of the hydrothermal system. It can be concluded the Acoculco geothermal area is in its final hydrothermal stage, since a change in the hydrothermal regime from convective to forced-convective or conductive has occurred, according to studies of hydrothermal mineralogy and other considerations. It is notable that the system is not recycling, perhaps because the rocks have not allowed it to, and therefore is ending. This, of course, has not been an obstacle to the presence of large volumes of hot (300 degrees Celsius) hornfels and granite opening up possibilities for the exploitation of an Enhanced (or Engineered) Geothermal System (EGS). The possibility of improving reservoir rocks permeability (hornfels and granite) by conventional means remains to be investigated. [Spanish] La zona geotermica de Acoculco, Pue., se localiza a 180 km de distancia de la ciudad de Mexico, D.F. Exhibe dos areas alteradas hidrotermalmente con descargas acido-sulfatadas frias y algunas mofetas, asociadas a una red estructural compleja configurada en un espesor de 2000 m de rocas volcanicas del Cuaternario-Terciario, calizas metamorfizadas del Cretacico e incluso granitos del Cretacico. Esta particularidad parece encajar conceptualmente en los denominados

  20. Ethylene, Enzymatic and Respiratory Pattern Evolution in Loquat (Eriobotrya japonica (Thunb. Lindl. cv. Golden Nugget in the Last four Sequential Stages of Maturation Evolución del Patrón Respiratorio, Enzimático y de Etileno del Níspero Japonés (Eriobotrya japonica (Thunb. Lindl. cv. Golden Nugget en los Últimos Cuatro Estadios Secuenciales de Madurez

    Directory of Open Access Journals (Sweden)

    Pedro L Undurraga M

    2011-12-01

    (PG, y celulasa. Los resultados muestran que el etileno incrementó su concentración al momento de quiebre de color, lo cual no fue equivalente en el cambio de la tasa respiratoria. La actividad de la enzima peroxidasa se incrementó desde el color verde al quiebre de color, mientras que las enzimas PME, celulasa, y PG mostraron una reducción constante desde el color verde hasta el color anaranjado y la PPO no se vió alterada en los cuatro estadios estudiados. Respecto a la calidad, a partir del quiebre de color se incrementaron los sólidos solubles hasta 11,8 °Brix y se redujo la acidez titulable desde 0,67 a 0,28 g L-1 de acido málico. Basado en estos resultados, se concluye que hacia el término de su desarrollo el fruto de níspero cv. Golden Nugget presenta un comportamiento enzimático y del etileno similar al que muestran frutos de tipo climatérico.

  1. Performance of a small stand alone photovoltaic-wind system at El Oyameyo D.F., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Juarez, A; Campos, J [Centro de Investigacion en Energia, UNAM, Mexico, D. F. (Mexico); Tiburcio Silver, A [Instituto Tecnologico de Toluca-Division de Posgrado, Toluca (Mexico)

    1998-12-31

    hibrido fotovoltaico-viento. La potencia electrica instalada para los sistemas FV autocontenidos estan en el rango de 48 W-p hasta 768 W-p. Entre estos hay 4 sistemas FV que estan configurados en sistemas regulados de CD y otros 6 son sistemas regulados de CA. Todos estos sistemas utilizan bancos de baterias de plomo-acido (selladas o ventiladas) para almacenar la energia producida diariamente por los sistemas. El sistema hibrido FV-Viento esta formado actualmente por un aerogenerador de 5.0 Kw, un arreglo FV de 768 W-p, un banco de baterias de almacenamiento de 37.8 Kw-h y un inversor de DC/AC de 5.0 Kw. En este articulo se reporta la electricidad generada, el patron de carga y el comportamiento general del sistema hibrido fotovoltaico-viento. Se presentan tambien las caracteristicas tecnicas, las pruebas de energia del sistema hibrido y la experiencia obtenida del manejo de la energia y del mantenimiento del sistema para todos los sistemas. Se encontro que todos los sistemas habian demostrado buen desempeno a satisfaccion del usuario.

  2. Tyrosine Metabolism in the Blowfly, Calliphora Erythrocephala; Metabolisme de la tyrosine dans la Calliphora Erythrocephala; Metabolizm tirozina u myasnoj mukhi, Calliphora Erythrocephala; Metabolismo de la tirosina en la mosca Calliphora Erythrocephala

    Energy Technology Data Exchange (ETDEWEB)

    Sekeris, C. E. [Physiological Chemistry Institute, University of Munich, Munich (Germany)

    1963-09-15

    estadio las larvas catabolizan tirosina por transaminacion, dando acido p-hidroxifenilpinivico, y por reduccion, dando los acidos p-hidroxifenillactico y p-hidroxifenil propionico. Esta transicion metabolica desde la transaminacion a la hidroxilacion y descarboxilacion se debe a la hormona de la glandula protoracica (ecdyson) y se puede inhibir ligando o destruyendo la glandula anular. Si se inyecta ecdyson en los animales ligados se produce al cabo de 10 a 14 h una activacion de la dopadecarboxilasa, debida probablemente a la biosintesis de proteinas enzimaticas. La accion de la hormona sobre el mecanismo de biosintesis no es directa sino indirecta, dejandose sentir sus primeros efectos sobre los cromosomas (fenomeno de turgencia). La hipotesis de que se partio es que la hormona que actua sobre las sustancias geneticas y que sufre la accion de estas estimula la sintesis de un ARN especifico (vehiculo) que se traslada al citoplasma y produce proteinas enzimaticas. (author) [Russian] Sklerotizatsiya, t.e. prevrashchenie myagkoj beloj kutikuly lichinki v zatverdevshij temnyj puparij, proiskhodit blagodarya vzaimodejstviyu ortokhinonov s belkami kutikuly. S pomoshch'yu mechennykh izotopami aminokislot bylo pokazano, chto N-atsetildopamin yavlyaetsya blizhajshim predshestvennikom sklerotiziruitsikh khinonov u Calliphora erythrocephala. Promezhutochnymi stadiyami v biosinteze N-atsetildopamina yavlyayutsya gidroksilirova- nie tirozina v dopa, dekarboksilirovanie dopa do dopamina i N-atsetilirovanie dopamina do N-atsetildopamina. Ehtot metabolicheskij protsess prevrashcheniya tirozina proiskhodit tol'ko u lichinok na poslednej stadii razvitiya. U lichinok v rannej faze tret'ej stadii proiskhodit katabolizatsiya ti rozina putem pereaminirovaniya v para-oksifenilpirovikogradnuzeh kislotu i vosstanovlenie v paraoksifenilmolochnuyu para-oksifenilpropionovuyu kislotu. Metabolicheskoe smeshchenie ot pereaminirovaniya do gidroksilizatsii i dekarboksilizatsii vyzyvaetsya gormonom

  3. A Procedure for the Determination of Alpha-Emitting Plutonium in Urine Using a Solid-State Counter; Methode de Determination du Plutonium Emetteur Alpha Present dans l'Urine, au Moyen d'un Compteur a Semi-Conducteurs; Metod opredeleniya al'fa-izlucheniya plutoniya v moche s pomoshch'yu poluprovodnikovogo schetchika; Procedimiento para Determinar la Actividad Alfa del Plutonio en la Orina con Ayuda de un Contador de Estado Solido

    Energy Technology Data Exchange (ETDEWEB)

    Sandalls, F. J.; Morgan, A. [Health Physics and Medical Division, Atomic Energy Research Establishment, Harwell (United Kingdom)

    1964-10-15

    definitiva, la orina se calcina en humedo y el residuo se disuelve con acido clorhidrico. El plutonio (IV) presente en la solucion asi obtenida se coprecipita con cupferrato de hierro y se extrae con cloroformo. Una vez evaporado este,, se oxida el residuo, se disuelve en acido clorhidrico y el hierro se extrae con eter diisopropflico. Seguidamente se evapora a sequedad la fase acuosa que contiene, al plutonio y se disuelve en una solucion acida de sulfato amonico desde la cual se separa el plutonio por deposito electrolitico sobre acero inoxidable. El rendimiento de esta ultima etapa es cuantitativo, siendo de 84 {+-} 7% para el proceso en conjunto. . El plutonio electrodepositado se recuenta con un detector de estado solido (diode de union de silicio) en un contador especialmente construido para este fin. La baja actividad de fondo inherente de este tipo de contadores puede disminuirse aun mas contando solamente las particulas alfa de energia comprendida entre 4.2 y 5,4 MeV. El buen poder de resolucion que se obtiene con capas delgadas de plutonio electrodepositado permite emplear un canal tan estrecho sin que la eficacia de recuento disminuya apreciablemente. Al efectuar el recuento en este intervalo restringido, la actividad de fondo debida a los reactivos y a la eliminacion incompleta de las impurezas de emisores alfa de la orina queda reducida tambien a la mitad, esto es, a un valor del orden de 0,01 pcuries por muestra de 24 horas. El limite de deteccion mediante este metodo es aproximadamente de 0,025 pc de {sup 239}Pu. (author) [Russian] Opisan metod prakticheskogo'opredelenija al'fa-izluchenija plutonija v moche. Pri razrabotke jetogo metoda sravnivalis' razlichnye metody koncentrirovanija, ochistki i jelektroliticheskogo osazhdenija plutonija ; podvoditsja itog jetih issledovanij. Soglasno prinjatomu v konechnom itoge metodu mochu podvergajut vlazhnomu ozoleniju, osadok rastvorjajut v soljanoj kislote. Plutonij (IV) podvergajut sovmestnomu osazhdeniju s

  4. Fission-Product Separation as a Final Solution to the Problem of Storing Highly Radioactive Waste; La Separation des Produits de Fission Comme Solution Definitive du Stockage des Dechets Fortement Radioactifs; 0412 042b 0414 ; La Separacion de los Productos de Fision Como Solucion Definitiva del Problema del Almacenamiento de los Desechos de Elevada Radiactividad

    Energy Technology Data Exchange (ETDEWEB)

    Raggenbass, A.; Lefevre, J. [Centre d' Etudes Nucleaires, Saclay (France)

    1963-02-15

    productos de fision concentrados podrian resolverse aislando el cesio-137 y el estroncio-90 con un factor de descontaminacion minimo de 10{sup 4}, lo que, despues de un tratamiento de efluentes ordinario permitiria proceder a la evacuacion al cabo de un periodo de 10 a 20 anos. La finalidad de esta memoria es exponer el estado de la cuestion en 1962. Los progresos realizados en los metodos de separacion del cesio y del estroncio permiten esperar la obtencion del mencionado factor 10{sup 4} en condiciones industrialmente explotables. He aqui los metodos que ofrecen mejores perspectivas: a) Para el cesio-137: la precipitacion mediante el acido fosfowolfrimico, el intercambio a base de una sal de amonio de un heteropoliacido, la fijacion mediante un fosfate de circonio, b) Para el estroncio-90: la precipitacion del oxalato, la extraccion mediante el acido di-2-etilhexil- fosforico, el intercambio a base de sales diversas, sulfato de estroncio, etc. Estos progresos en el terrenorde la quimica, a los que se suman los progresos realizados en el tratamiento industrial de los efluentes, permiten considerar tecnicamente posible la solucion propuesta por Glueckauf. Al mismo tiempo, el desarrollo de la utilizacion de grandes cantidades de productos de fision, particularmente dentro del marco de los programas SNAP, justifica la inversion de capitales que seran recuperados, poit lo menos parcialmente, mediante la venta de los productos fabricados. Es evidente que las fuentes refractarias, de muy alta resistencia frente a todos los agentes exteriores de ataque, constituyen la forma de almacenamiento mas satisfactoria para productos tan peligrosos y de periodo tan prolongado. Los autores consideran, pues, que desde el punto de vista tecnico y psicologico el empleo de fuentes concentradas con abundante revestimiento es el medio de almacenamiento que ofrece mayores garantias. Valdria la pena efectuar un estudio completo y detallado del metodo descrito comparandolo con el metodo de

  5. Treatment, Processing and Future Disposal of Radioactive Wastes at the Idaho Chemical Processing Plant; Traitement et Elimination Future des Dechets Radioactifs a l'Usine de Traitement Chimique de L'Idaho; 0410 041d 0414 ; Tratamiento y Evacuacion de Desechos Radiactivos en la Planta de Tratamiento Quimico de Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, James I. [Phillips Petroleum Company, Atomic Energy Division, Idaho Falls (United States)

    1960-07-01

    incorporer dans d'autres substances les dechets a eliminer est la production d'une masse solide contenant les produits de fission. L'inconvenient que constituent les frais de traitement plus eleves peut etre parfois compense par une reduction des frais de stockage. La faible conductivite thermique des corps solides donne plus d'importance a la temperature de stockage que dans le cas de liquides. Les dechets acides de nitrate d'aluminium provenant du traitement des combustibles du type de ceux que l'on utilise dans les reacteurs d'essai des materiaux peuvent etre transformes en aluminium granule par voie de calcination dans un lit fluidifie a une temperature allant de 350 Degree-Sign a 550 Degree-Sign C. Les principaux elements de l'installation sont: un calculateur chauffe au NaK, un systeme d'epuration des gaz d'echappement et un ensemble de recipients pour le stockage des matieres solides obtenues. L'auteur donne un apercu du processus de traitement et du programme de recherche et de mise au point. L'auteur examine un certain nombre de systemes futurs de stockage et leurs incidences sur le milieu ambiant en prenant pour base les resultats positifs de la demonstration du systeme de calcination a ht fluidifie et d'emmagasinage a haute temperature ainsi que d'autres considerations. (author) [Spanish] En la planta de tratamiento quimico de Idaho, los desechos acidos procedentes de la recuperacion del uranio enriquecido de los combustibles nucleares que contienen aluminio, zirconio y acero inoxidable se almacenan en tanques subterraneos de dos formas, con capacidades nominales de 30,000 y 300,000 galones. El autor describe la organizacion y funcionamiento de la seccion de tanques, asi como los metodos utilizados para la evacuacion de desechos de baja actividad. La evacuacion de desechos con arreglo al, principio de la 'concentracion y confinamiento' tiene por finalidad la obtencion de una masa solida que retenga los productos de fision. Los gastos mas elevados que este

  6. The Metabolism of Tritium-Labelled Epinephrine in Man; Metabolisme de l'Adrenaline Tritiee dans l'Organisme Humain; 041c 0435 0414 ; Metabolismo de la Adrenalina Marcada con Tritio en el Hombre

    Energy Technology Data Exchange (ETDEWEB)

    Labrosse, E. H.; Axelrod, J.; Kopin, I. J.; Kety, S. S. [National Institute of Health, Bethesda, MD (United States)

    1962-02-15

    nuevos metabolitos. En 12 varones normales, el 92,6 {+-} 7,7% del tritio de la adrenalina-3 administrada se excreto por la orina al cabo de 54 h. Este tritio estaba repartido entre los siguientes compuestos : adrenalina sin alterar 6,8 {+-} 1,5%, metanefrina libre 5,2 {+-} 1,1%, glucuronato de metanefrina 6,0 {+-} 1,5%, sulfato de metanefrina 29,5 {+-} 9,0%, 3-metoxi-4-hidroxifenilglicol 7,1 {+-} 1,4%, acido 3,4-dihidroximandelico libre y conjugado 1,6 {+-} 0,6% y acido 3-metoxi-4-hidroximandelico 41,2 {+-} 8,4%. Como demuestran estos experimentos y otros similares, el empleo de la adrenalina tritiada permite formarse una idea mucho mas clara del metabolismo de esta importante hormona en el hombre. (author) [Russian] Predstavljaet interes issledovanie metabolizma adrenalina u cheloveka. Izuchenie metabolizma adrena- lina u zhivotnyh pokazalo vozmozhnye korni ego metabolizma, no dozy radio- aktivnosti i katehin amina byli vyshe urovnej, javljajushhihsja bezopasnymi dlja cheloveka. Rannie issledovanija metabolizma jetogo gormona u cheloveka ogranivalis' otnositel'no nizkoj udel'noj aktivnost'ju mechenogo adrjonalina. Ispol'- zovanie tritirovannogo adrenalina (7-N{sup 3}-s1)-adrenalin-s1-kilaja sol') pozvolilo provesti bolee polnoe vosstanovlenie vvodimoj raidoaktivnosti, a bolee vyso- kaja udel'naja aktivnost' (vyshe 300 {mu}c/mg) pozvolila izolirovat' i opredelit' kolichestvo novyh metabolitev. Y 12 muzhchin 92,6 {+-} 7,7% tritija v vvedennom N{sup 3}-adrenaline vyshlo v mochu cherez 54 chasa posle vvedenija tritirovannogo adrenalina. Mechennyj tritiem sostav mochi okazalsja sledujushhim: neizmenennyj adrenalin 6,8 {+-} 1,5%, svobod- nyj metanefrin (metanephrino) 5,2 {+-} 1,1%, metanefrinovyj gljukuronid (glucuronide) 6,0 {+-} 1,5 % , metanefrinovyj sul'fat 29,5 {+-}9,0%, Z-metoksi-4- gidrooksifenilglikol' 7,1 {+-} 1 , 4 % , svobodnaja i soprjazhennaja 3,4-dioksimin- dal'naja kislota 1,6 {+-} 0,6% i Z-metoksi-4-oksimindal'naja kislota 41,2 {+-} 8,4%. Podtverzhdennoe jetim

  7. Some solvent extraction studies of trivalent metal halides; Quelques etudes sur l'extraction par solvant d'halogenures de metaux trivalents; Izuchenie ehkstraktsii nekotorykh rastvoritelej iz trekhvalentnykh metallicheskikh galoidov; Algunos estudios de la extraccion mediante disolventes de haluros de metales trivalentes

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Jr, R J; Mendez, J; Irvine, Jr, J W [Department of Chemistry and Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA (United States)

    1962-03-15

    el orden de magnitud del coeficiente varia en un intervalo de 10{sup 5}. Los autores explican los datos obtenidos sobre la base de la ionizacion del acido complejo HMX{sub 4} en estos disolventes, cuyas constantes dielectricas son relativamente elevadas. Empleando un metodo ideado por Poskanzer, han calculado la constante de ionizacion del electrolito soporte, HCl o HBr, en la fase no acuosa a partir de las variaciones que el coeficiente de extraccion experimenta en funcion de las concentraciones del metal. Las variaciones del coeficiente de extraccion con la concentracion de HX han servido para calcular las constantes de estabilidad de las especies complejas MX{sub 3} y MX{sub 4}{sup -}. Como se trata de reacciones en fase acuosa, las constantes son independientes del disolvente organico que se emplee. Para el sistema In (III)-HCl los autores obtuvieron resultados perfectamente concordantes tanto al emplear eter bis (2-cloroetilico) como nitrobenceno. Los autores no consiguieron evaluar las constantes de los complejos de cloruro y bromuro de galio porque dichos compuestos solo se forman en un intervalo de concentraciones de acido muy estrecho. Los valores del cociente (GaCl{sub 4}{sup -})/{Sigma} Ga (III) en funcion de la concentracion de HCl, calculados a partir de los datos de extraccion, concuerdan con los datos que Kraus y Nelson obtuvieron por mediciones del intercambio ionico. (author) [Russian] Metod mechenykh atomov pozvolil provesti izuchenie fiziko-khimicheskogo raspredeleniya Ga (III) i In (III) mezhdu vodnymi rastvorami HCl i HBr i organicheskimi rastvoritelyami, dvojnym ehfirom (2-khloroehtil) i nitrobenzolom. Na osnove izmerenij koehffitsientov ehkstraktsii pri kontsentratsii metalla vyshe 10{sup 10} i pri kolebanii dannogo koehffitsienta v predelakh 10{sup 5} tshchatel'no bylo razrabotano ehmpiricheskoe povedenie dannykh sistem. Rezul'taty vyrazhalis' v stepeni ionizatsii slozhnoj kisloty, HMX{sub 4}, izvestnoj v kachestve rastvoritelya s otnositel

  8. La madurez del fruto y el secado del cáliz influyen en el comportamiento poscosecha de la uchuva, almacenada a 12 °C (Physalis peruviana L.

    Directory of Open Access Journals (Sweden)

    Novoa Rafael H.

    2006-06-01

    C y 24 oC durante 6 h. Se determino la intensidad respiratoria por cromatografia de gases y el contenido de acidos organicos y azucares por cromatografía liquida de alto desempeno. Los resultados mostraron que la uchuva es un fruto climaterico, que presenta el maximo de respiracion a los 12 d de almacenamien to. Los tratamientos con secado del caliz a 24 oC fueron mas eficientes, ya que el fruto respiro menos, comparado con las uchuvas cuyo caliz fue secado a 18 oC. Entre los acidos organicos evaluados, el acido citrico resulto predominante en  el fruto, seguido por los acidos malico, ascorbico,  tartarico y oxalico, respectivamente. La perdida de acido as corbico en el fruto fue total despues de12 d de almacenamiento. Los azucares predominantes en la uchuva fueron, en su orden, sacarosa, glucosa y fructosa. Frutos cosechados en grado de madurez (GM 4 con secado del caliz a 24 oC y aquellos en GM 5 y secados a 18 °C conservaron mejor la concentración de sacarosa. Se presento Botrytis cinerea en frutos con secado del caliz a 18 oC.

  9. Design of a Chemical Processing Apparatus for Radioisotopes of Short Half-Life; Projet d'une Installation de Traitement Chimique de Radioelements a Courtes Periodes; ПРОЕКТ УСТАНОВКИ ДЛЯ ХИМИЧЕСКОЙ ОБРАБОТКИ КОРОТКОЖИВУЩИХ РАДИОЭЛЕМЕНТОВ; Proyecto para una Instalacion de Tratamiento Quimico de Radioelementos de Periodo Corto

    Energy Technology Data Exchange (ETDEWEB)

    Douis, M.; Valade, J. [Centre d' Etudes Nucleaires, Saclay (France)

    1963-03-15

    ) [Spanish] Los autores consideran conveniente indicar a los radioquimicos que tengan la posibilidad de utilizar un reactor pequeno (por ejemplo, de un flujo de 10{sup 12}n/cm{sup 2}s) que radioelementos pueden preparar y cual es el material minimo que precisaran para ello. La memoria comprende tres partes principales: 1. Radioelementos posibles. Estos pueden clasificarse en dos categorias: (a) Radioelementos para fines medicos, entre los que se citan: el sodio-24, el potasio-42, el bromo-82, el cobre-64, el arsenico-76, el mercuxio-197 y el oio-198 coloidal. (b) Radioelementos para fines cientificos o industriales,ademas de los ya mencionados: el antimonio-122, el arsenico-77, el manganeso-56 y el oro-198 (cloruro). 2. Tratamientos quimicos. Tambien a este respecto, los radioelementos se pueden dividir en dos categorias: (a) La simple disolucion, que casi siempre se efectua en agua o en acidos diluidos, en frio, o en acidos concentrados, en caliente. A esta categoria pertenecen: el sodio-24, el potasio-42, el bromo-82, el mercurio-197, el antimonio-122, el manganeso-56 y el oro-198 (cloruro). (b) Las separaciones o las transformaciones complicadas; pertenecen a esta clase las preparaciones obtenidas por efecto Szilard-Chalmers y por reacciones (n, p) y (n, {gamma}) seguidas de desintegraciones oo de la,formacion de coloides. Como ejemplos pueden citarse: el cobre-64, el arsenico-76, el arsenico-77, y el oro-198 coloidal. 3. Recintos de preparacion. Estos radioelementos deben prepararse en recintos estancos y protegidos y agruparse segun sus afinidades. Les autores proponen una instalacion que comprende tres cajas de 2 m de largo por 1 m de profundidad, unidas entre si por un transportador y cuyas finalidades serian las siguientes; Primera caja: Introduccion de los recipientes, vaciado y preparacion del sodio-24, del potasio-42 y del bromo-82; Segunda caja: Preparacion de dos de los tres radioelementos siguientes: cobre-64, arsenico-76, oro-198 coloidal; Tercera caja

  10. A Aspirina e a Asma

    Directory of Open Access Journals (Sweden)

    K.S. Babu

    2001-03-01

    Full Text Available RESUMO: A aspirina é não só o fannaco me1hor estudado em todo o mundo, como o mais frequentemente uti1izado em todos os tempos. Alem das suas propriedades como analgesico e antipiretico, o acido acetilsalicflico (AAS e urn inibidor da agregação plaquetária, o que the confere urn papel essencial na profilaxia do tromboembolismo e na prevenção dos acidentes cardio e cerebro-vasculares.A associação da sensibilidade á aspirina, com a asma e a polipose nasal, descrita pela primeira vez por Femand Widal e colaboradores, constitui a trfade da “Asma lnduzida pela Aspirina” (AlA e refere-se ao desenvolvimento de urn quadro de broncoconstrição em indivfduos asmaticos após ingestao de aspirina. Nestes doentes, os sintomas agudos sobrepõem-se ao quadro clfnico de asma crónica grave. As crises de asma podem ser desencadeadas por pequenas quantidades de AAS ou de outros anti-inflamatórios nao ester6ides (AINE’ s.A prevalência da AIA na comunidade é incerta, mas os doentes com AIA constituem 10 a 20% da popula9ao asmatica, sendo a AIA mais frequente nas mulheres. Os autores deste trabalho fazem uma revisão teórica da AIA, descrevendo a apresentação clfnica, os mecanismos patogenicos, o diagnóstico e o tratamento deste síndrome.A asma e uma doença inflamatória crónica das vias aéreas. Neste estado de inflamação continua, a exposiyao aaspirina provoca no subgrupo de doentes com AIA uma acentuayao temporaria do processo inflamat6rio, que conduz á exacerbayao da asma. Embora assemelhando-se as reacçães de hipersensibilidade imediata, a AIA nao parece ser mediada por mecanismos dependentes da IgE, daí estas reacçães scrcm dcsignadas de “anafilactóides”.A hipersensibilidade à aspirina parece antes ser mediada por um desvio da via metab6lica do acido araquidónico no sentido da produção excessiva de leucotrienos, por

  11. Lens Opacification in Mice Exposed to Monoenergetic Fast Neutrons; Opacite du Cristallin chez la Souris Exposee aux Neutrons Rapides; Katarakty u myshej, obluchennykh monoehnergeticheskimi bystrymi nejtronami; Opacidad del Cristalino en los Ratones Expuestos a los Neutrones Rapidos Monoenergeticos

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, J. L.; Bond, V. P.; Rossi, H. H. [Medical Research Center, Brookhaven National Laboratory, Upton, NY (United States); Radiological Research Laboratory, Department of Radiology, Columbia University, New York, NY (United States)

    1964-05-15

    apres exposition a des doses relativement faibles de rayonnements. On a etudie les mecanismes de guerison dans plusieurs systemes cellulaires, avec des neutrons rapides monoenergetiques, et avec des rayons X ou des rayons gamma. On etudie maintenent les dommages chromosomiques, d'apres la frequence des anaphases anormales dans la regeneration du foie qui surviennent trois mois apres l'irradiation, chez des souris exposees aux rayons gamma avec des debits de doses variant de 0,2 a 100 rad /min. (author) [Spanish] Son muy numerosos los estudios de las reacciones radiologicas de los mamiferos pequefios, desde el nivel infracelular hasta el del organismo entero, llevados a cabo con radiaciones de baja TLE, tales como los rayos X o gamma. En cambio, son menos amplias las investigaciones efectuadas con radiacones de TLE mas elevada, como los neutrones rapidos. Y aun, en estas ultimas, la irradiacion se realizo con neutrones de una extensa gama energetica, y por lo tanto, de muy variada TLE. Ciertas reacciones entre un haz cargado y un blanco dan origen a neutrones cuyas energias dependen directamente del angulo que forman el eje de emision con el eje haz-blanco. Los autores emplearon una de aquellas reacciones en sus estudios de laboratorio, a saber, la reaccion proton/tritio. Por medio de la reduccion de peso del bazo y del timo en el raton, se ha comprobado que la eficacia biologica relativa (referidas a rayos X de 250 kVp)es del orden de 4 para una energia neutronica de 0,43 MeV, y se reduce hasta 3 para 1,80 MeV. El estudio del agotamiento de los espermatogonios da valores algo mayores de la EBR, pero su disminucion al aumentar la energia neutronica es similar. Dentro del mismo intervalo de energias neutronicas, se examino la inhibicion del metabolismo del acido nucleico en el intestino y la medula osea (mediante precursores de dicho acido nucleico marcados con radioisotopos) y los valores de la EBR obtenidos son generalmente menores. Se comprobo que la eficacia de los

  12. Technical feasibility of using silver and copper ions electro generated in the microbiological control of cooling systems; Factibilidad tecnica para emplear iones plata y cobre electrogenerados en el control microbiologico de los sistemas de enfriamiento

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Susana M; Martinez Meza, Esteban; Alvarez Gallegos, Alberto [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2001-07-01

    sistema continuo el pH se mantuvo en el intervalo de pH de 7 a 8 mediante la adicion de acido sulfurico y se conservo un delta de temperatura de 10 (27 {+-} 5 ). El pH, la conductividad y la temperatura se midieron en forma continua. Se muestran graficas de efecto de iones plata/cobre sobre el aniquilamiento de bacterias coliformes totales y coliformes fecales se da como figura el efecto de la concentracion del ion metalico plata sobre el aniquilamiento de bacterias relacionadas con fierro. Se puede concluir que los sistemas de planta, plata/cobre y cobre estudiados resultaron ser una buena alternativa con un minimo impacto ambiental para sustituir el cloro en los sistemas de enfriamiento. Estos sistemas lograron abatir a las poblaciones bacterianas promotoras de la corrrosion influenciada microbiologicamente y del ensuciamiento biologico a niveles de 1000 ufc/mL y menores compitiendo con los tratamientos de aguas de enfriamiento convencionales. (abstract truncated)

  13. Comparison of the Economic Aspects of the Treatment and Storage of Fission Products from Installations Processing Irradiated Natural Uranium; Aspects Economiques Compares du Traitement et du Stockage des Produits de Fission Issus des Usines de Traitement de l'Uranium Naturel Irradie; Sravnitel'nye ehkonomicheskie aspekty obrabotki i khraneniya produktov deleniya, poluchaemykh na zavodakh po pererabotke obluchennogo prirodnogo urana; Aspectos Economicos Comparados del Tratamiento y del Almacenamiento de los Productos de Fision que Salen de las Plantas de Tratamiento de Uranio Natural Irradiado

    Energy Technology Data Exchange (ETDEWEB)

    Thiriet, L.; Lesur, P.; Giraud, R. [Commissariat a l' Energie Atomique, Paris (France); Wanlin, J. [Societe Saint-Gobain Techniques Nouvelles, Paris (France)

    1966-02-15

    reservoirs pouvant etre construits, et on determine la taille et la cadence optimales de leur mise en service, compte tenu des caracteristiques des produits de fission a stocker et pour diverses capacites de l'usine de traitement de l'uranium naturel irradie. Ils montrent que, si le cout de stockage depend des hypotheses faites sur la duree de vie des installations, le taux d'interet, les frais d'exploitation, le choix de la politique optimale par contre (tailles et cadences de mise en service) est independant de ces hypotheses et n'est lie qu'a la loi de variation du cout des reservoirs selon leur taille. On obtient ainsi le cout optimise de stockage indefini de ces effluents. Dans une troisieme partie, les auteurs comparent a cette solution du stockage indefini d'autres politiques possibles de gestion des produits de fission: vitrification et separation du Cs et du Sr. Ils situent economiquement ces diverses alternatives et esquissent des solutions possibles a long terme. (author) [Spanish] Despues de recordar las principales practicas administrativas que suelen aplicarse a los productos de fision, los autores exponen sucintamente las caracteristicas tecnicas esenciales de las instalaciones de almacenamiento en acero inoxidable (en medio acido) utilizadas en Francia y analizan la estructura de sus costos. Muestran hasta que punto esos costos dependen de la radiactividad de las soluciones almacenadas y del calor que desprenden. En la segunda parte de la memoria se examina el costo del almacenamiento segun las dimensiones de los depositos que pueden construirse, se determinan las dimensiones optimas de estos depositos y se indica el ritmo mas conveniente para su puesta en servicio teniendo en cuenta las caracteristicas de los productos de fision que es preciso almacenar y las diversas capacidades de las plantas de tratamiento de uranio natural irradiado. Se demuestra que si bien el costo del almacenamiento depende de algunas hipotesis (duracion de la vida util de las

  14. The Use of Ionizing Radiation in the Vulcanization of Silicon Rubber; Utilisation des radiations ionisantes pour la vulcanisation du caoutchouc au silicone; Ispol'zovanie ioniziruyushchikh izluchenij dlya vulkanizatsii silikonovogo kauchuka; Empleo de las radiaciones ionizantes en la vulcanizacion del caucho de siliconas

    Energy Technology Data Exchange (ETDEWEB)

    Kuzminsky, A S; Nikitina, T S; Oksentevich, L A [Rubber Research Institute, Moscow, Union of Soviet Socialist Republics (Russian Federation)

    1960-07-15

    'equilibre et du gonflement maximum apres immersion dans du benzol). Ils ont etudie les variations de la resistance a la rupture et de l'allongement relatif au cours de l'exposition aux radiations. Ils ont selectionne les regimes optimaux de vulcanisation et determine les coefficients physico-chimiques fondamentaux des vulcanisants. Ils ont etudie egalement la variation des proprietes des vulcanisants radiatifs au cours du vieillissement thermique, par des temperatures differentes (150{sup o}, 200{sup o} et 250{sup o}). La vulcanisation radiative evite l'emploi de temperatures elevees et le maintien prolonge d'une temperature constante apres vulcanisation. Cette nouvelle methode de vulcanisation permet d'utiliser, en guise de produits d'addition, des noirs de fumee. L'utilisation des radiations ionisantes permet de simplifier la technique de vulcanisation du caoutchouc au silicium et d'ameliorer les proprietes des vulcanisants. (author) [Spanish] La principal finalidad de este trabajo es estudiar detalladamente las propiedades de los materiales obtenidos por irradiacion de una mezcla de elastomero de polidimetilsiloxano y distintas cargas (acido silicico especial, bioxido de titanio, hollin y negro de humo). La irradiacion se efectuo con un aparato de rayos X de gran potencia o con una fuente gamma de {sup 60}Co de una intensidad equivalente a la de 20 000 gramos de radio. La velocidad relativa de reticulacion de las sustancias vulcanizadas se determino segun la magnitud de la constante de equilibrio y el grado maximo de turgencia en benceno. Se estudiaron las variaciones de la resistencia a la traccion y del alargamiento especifico durante el proceso de irradiacion. Se eligieron los regimenes optimos de vulcanizacion y se determinaron las princiales propiedades fisicas y mecanicas de las sustancias vulcanizadas. Asimismo, se estudiaron las variaciones que las propiedades de las sustancias radiovulcanizadas experimentan en el transcurso del envejecimiento termico a distintas

  15. Assessment of a sequential extraction protocol by examining solution chemistry and mineralogical evolution

    Science.gov (United States)

    Maubec, Nicolas; Pauwels, Hélène; Noël, Hervé; Bourrat, Xavier

    2015-04-01

    of them are able to leach several solid phases. In this context, the aim of the present study is to investigate the effectiveness and the selectivity of different reagents for metal extraction from target geochemical fraction. It is based on solid analyses with the use of X-ray diffraction and a scanning electron microscopy (SEM) coupled to a microRaman spectrometer in conjunction with chemical analyses of extracting solutions at each step. This methodology provides the opportunity to assess more accurately the effect of each reagent. The study focuses on extraction of Cu and Zn from sediment samples collected at two sites from river banks and characterized by presence of Quartz, Feldspar K, Micas, Kaolinite but with differences regarding accessory phases (pyrite, organic matter, iron oxy- hydroxide, calcite). The interaction of the samples with eight different reagents was assessed and compared (Ca(NO3)2 and CaCl2 for the exchangeable fraction; buffered solutions of sodium acetate/acetic acid at pH = 5.5 and pH = 5 for the acido-soluble fraction; hydroxylamine hydrochloride and a solution of ammonium oxalate/oxalic acid for reducible fraction; hydrogen peroxide and sodium hypochlorite for the oxidizable fraction. In-depth characterization of solid residue at each step allowed proposing the best protocol for both metals. Anderson, P., Davidson, C. M., Duncan, A. L., Littlejohn, D., Ure, A. M., and Garden, L. M. (2000). Column leaching and sorption experiments to assess the mobility of potentially toxic elements in industrially contaminated land. Journal of Environmental Monitoring, 2. Arey, J. S., Seaman, J. C., and Bertsch, P. M. (1999). Immobilization of uranium in contaminated sediments by hydroxyapatite addition. Environmental Science & Technology, 33, 337-342. Brannon, J. M., and Patrick, W. H. (1987). Fixation, transformation, and mobilization of arsenic in sediments.Environmental Science & Technology, 21, 450-459. Cornu, S., and Clozel, B. (2000). Extractions

  16. Trace Analysis of Boron in Nuclear Graphite by Means of Gas Chromatography; Analyse de traces de bore dans le graphite nucleaire au moyen de la chromatographie gazeuse; Analiz metodom gazovoj khromatografii sledov bora v yadernom grafite; Analisis de vestigios de boro en el grafito nuclear por cromatografia de gases

    Energy Technology Data Exchange (ETDEWEB)

    Zado, F. [Rudjer Boskovlc Institute, Zagreb, Yugoslavia (Croatia)

    1963-11-15

    en raison de la sensibilite du trichlorure de bore a l'humidite. (author) [Spanish] Hasta ahora no se han publicado datos sobre la aplicacion de la cromatografia de gases a la valoracion de vestigios de boro en el grafito. El autor examina los siguientes metodos de transformacion del boro en compuestos volatiles: a) Ignicion del grafito en corriente de oxigeno y transformacion subsiguiente del acido de boro en borato de metilo volatil, que se analiza luego en un cromatografo de gases Dilkens Aerograph H, modelo 96, con columna de silicona e hidrogeno como portador (metodo de concentracion). b) Extraccion del boro presente en el grafito por medio de fluoruro de sodio a 2800{sup o}C con cloracion y retencion simultaneas del tricloruro de boro, que luego se analiza (metodo directo). El autor uso un cromatografo de gases fabricado por el mismo, con un detector de conductividad termica y nitrogeno como portador. La columna era de vidrio con 20% en peso de fluorocarburo aceitoso sobre kieselgur. En vista de la sensibilidad del tricloruro de boro frente a la humedad, fue preciso adoptar medidas de precaucion especiales. (author) [Russian] V literature otsutstvuet dannye o primenenii gazovoj khromatografii dlya analiza sledov bora v grafite. Obsukhdayutsya sleduyushchie metody prevrashcheniya bora v ego letuchie soedineniya: a) Prokalivanie grafita v potoke kisloroda s posleduyushchim prevrashcheniem okisi bora v letuchij bornometilovyj ehfir, kotoryj zatem issleduetsya metodom gazovoj khromatografii na aehrografe Dilkensa, model' H 96, s kremnievoj kolonkoj i vodorodom v kachestve nositelya (metod kontsentratsii); i b) Ehkstragirovanie bora iz grafita s pomoshch'yu ftoristogo natriya pri 2800{sup o}C s odnovremennym khlorirovaniem i ulavlivaniem trekhkhloristogo bora, kotoryj zatem podvergaetsya analizu (pryamoj metod). Ispol'zovalas' ustanovka dlya gazovoj khromatografii kustarnogo proizvodstva s teploprovodnym detektorom i azotom v kachestve nositelya. Kolonka byla

  17. Electron and Proton Transfer by the Grotthuss Mechanism in Aqueous Solution and in Biological Systems; Transfert d'Electrons et de Protons par le Mecanisme de Grotthuss en Solution Aqueuse et dans les Systemes Biologiques; Perenos ehlektronov i protonov mekhanizmom grotkhusa v vodnom rastvore i v biologicheskikh sistemakh; Transferencia Electronica y Protonica por el Mecanismo de Grotthuss en Soluciones Acuosas y en Sistemas Biologicos

    Energy Technology Data Exchange (ETDEWEB)

    Horne, R. A.; Courant, R. A.; Johnson, D. S. [Arthur D. Little, Inc. Cambridge, MA (United States)

    1965-10-15

    conduction protonique selon la concentration par une equation, fondee sur la racine cubique de la concentration extrapolee, qui contient des termes d'Arrhenius ou les energies d'activation sont celles qui ont trait a la rotation de l'eau du solvant et a la formation de ' trous 'dans cette eau. Ainsi, l'energie chimique et l'energie electrique peuvent etre transmises rapidement par le mecanisme de Grotthuss sur des distances relativement grandes. Ces processus interviennent dans divers phenomenes importants en biologie, notamment dans la contraction musculaire et la chimie des pigments respiratoires. (author) [Spanish] El intercambio electronico Fe{sup II} - Fe{sup III}, asi como ciertas reacciones de oxidorreduccion biologica lenta, implican una transferencia de electrones en virtud de un mecanismo de Grotthuss pasando por puentes agua. A este mecanismo se debe asimismo la conductividad electrica, anormalmente elevada, de las soluciones acuosas de acidos. A presion ordinaria, la etapa que determina la velocidad del mecanismo de Grotthuss es la rotacion de la molecula de H{sub 2}O, posiblemente H{sub 3}O+, y no el propio salto del proton. El mecanismo de Grotthuss se limita al agua monomerica capaz de girar 'libremente' entre los grupos de Frank-Wen en agua liquida y no se verifica en las zonas relativamente ordenadas. La relacion entre la conduccion protonica y la concentracion se puede expresar mediante una ecuacion basada en la rafz ciibica de la concentracion extrapolada y que contiene terminos de Arrhenius en los cuales las energias de activacion son las correspondientes a la rotacion y a la formacion de 'huecos' en el agua disolvente. De este modo, la energia, sea quimica o electrica, puede ser transmitida rapidamente a distancias relativamente grandes por el mecanismo de Grotthuss. Estos procesos intervienen en numerosos fenomenos de importancia biologica, entre otros, la contraccion muscular y la quimica de los pigmentos respiratorios. (author) [Russian] Reakcija

  18. Efeito da fortificação alimentar com ácido fólico na prevalência de defeitos do tubo neural Efecto de la fortificación alimentaria con ácido fólico en la prevalencia de defectos del tubo neural Effects of folic acid fortification on the prevalence of neural tube defects

    Directory of Open Access Journals (Sweden)

    Sâmya Silva Pacheco

    2009-08-01

    Full Text Available OBJETIVO:Analisar o efeito de alimentos fortificados com ácido fólico na prevalência de defeitos de fechamento do tubo neural entre nascidos vivos. MÉTODOS: Estudo longitudinal de nascidos vivos do município de Recife (PE entre 2000 e 2006. Os dados pesquisados foram obtidos do Sistema Nacional de Informações de Nascidos Vivos. Os defeitos de fechamento do tubo neural foram definidos de acordo com o Código Internacional de Doenças-10ª Revisão: anencefalia, encefalocele e espinha bífida. Compararam-se as prevalências nos períodos anterior (2000-2004 e posterior (2005-2006 ao período mandatório à fortificação. Analisou-se a tendência temporal das prevalências trimestrais de defeitos do fechamento do tubo neural pelos testes de Mann-Kendall e Sen's Slope. RESULTADOS: Não se identificou tendência de redução na ocorrência do desfecho (Teste de Mann-Kendall; p= 0,270; Sen's Slope =-0,008 no período estudado. Não houve diferença estatisticamente significativa entre as prevalências de defeitos do fechamento do tubo neural nos períodos anterior e posterior à fortificação dos alimentos com acido fólico de acordo com as características maternas. CONCLUSÕES: Embora não tenha sido observada redução dos defeitos do fechamento do tubo neural após o período mandatório de fortificação de alimentos com ácido fólico, os resultados encontrados não permitem descartar o seu benefício na prevenção desta malformação. São necessários estudos avaliando maior período e considerando o nível de consumo dos produtos fortificados pelas mulheres em idade fértil.OBJETIVO:Analizar el efecto de alimentos fortificados con ácido fólico en la prevalencia de defectos del cierre del tubo neural entre nacidos vivos. MÉTODOS: Estudio longitudinal de nacidos vivos del municipio de Recife (Noreste de Brasil, entre 2000 y 2006. Los datos pesquisados fueron obtenidos del Sistema Nacional de Informaciones de Nacidos Vivos. Los

  19. Laser induced spectroscopy breakdown (LIBS) application to heavy metal detection in soils; Applicazioni della tecnica Laser induced breakdown spectroscopy (LIBS) alla determinazione dei metalli pesanti nei suoli

    Energy Technology Data Exchange (ETDEWEB)

    Barbini, R.; Fantoni, R.; Palucci, A.; Ribezzo, S.; Colao, F. [ENEA, Centro Ricerche Frascati, Frascati, RM (Italy). Div. Fisica Applicata; Capitelli, F. [Bari, Univ., Bari (Italy). Dipt. di Biologia e Chimica Agroforestale ed Ambientale

    2000-07-01

    composizione elementale del campione e, mediante l'utilizzo di emissioni di campioni a concentrazione nota, di risalire alle concentrazioni delle singole specie del campione. Il grande vantaggio di questa tecnica e' che non e' richiesto alcun trattamento del campione (come invece e' il caso in tecniche spettroscopiche tradizionali quale l'ICP, Inductively Coupled Plasma, che richiede la mineralizzazione del campione tramite attacco acido con acqua regia), se non il semplice compattamento tramite pressa meccanica. I risultati ottenuti dall'applicazione della tecnica LIBS al centro ricerche ENEA di Frascati sui campioni di suolo sono stati analizzati per confronto con i risultati ottenuti con una tecnica tradizionale quale l'ICP. Si osserva una sistematica sovrastima del valore LIBS rispetto a quello ICP, probabilmente imputabile alle differenze di matrice litologiche tra i campioni analizzati e quelli usati come riferimento. (abstract truncated)

  20. Chemical Changes Induced by Irradiation in Meats and Meat Components; Transformations Chimiques Provoquees par les Rayonnements dans les Viandes et Leurs Constituants; Khimicheskie prevrashcheniya v myasnykh produktakh i ikh sostavnykh chastyakh pod vozdejstviem oblucheniya; Alteraciones Quimicas Producidas por Irradiacion de las Carnes y de sus Componentes

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, C. Jr. [Pioneering Research Division, United States Army Natick Laboratories, Natick, MA (United States)

    1966-11-15

    veau; il a egalement analyse les produits volatils de la degradation, par les rayonnements de plusieurs acides amines et proteines, de graisses animales, d'esters methyliques d'acide gras et de triglycerides. L'auteur compare les resultats de l'analyse des substances constitutives de la viande soumises a l'irradiation avec ceux obtenus par l'irradiation de la viande elle-meme et de fractions distinctes de viande, ce qui permet de determiner l'apport de chaque fraction a l'ensemble. Il postule des mecanismes expliquant la formation des elements volatils dans chacune de ces fractions ainsi que les interactions entre les sub- stances, intermediaires des differentes fractions. (author) [Spanish] El mal sabor y el mal olor originados por la irradiacion de la carne conservada son un obstaculo para su aceptacion. Se cree que este sabor y este olor desagradables se deben a.los compuestos quimicos volatiles producidos por las radiaciones en las moleculas de proteinas y lipidos. Se han analizado los compuestos volatiles por cromatografia en fase gaseosa a temperaturas sumamente bajas y con arreglo a un programa, para determinar las mezclas complejas obtenidas, y por espectrometria de masas con exploracion rapida, para identificar los componentes separados. Se han efectuado analisis minuciosos de las sustancias volatiles formadas por irradiacion en carne picada de vaca, cerdo, carnero, cordero y ternera, asi como de los productos volatiles de degradacion originados por las radiaciones en varios aminoacidos y proteinas, grasas animales, esteres metilicos de acidos grasos y trigliceridos. Los resultados del analisis de los componentes de la carne irradiados se comparan con los obtenidos irradiando la carne misma y distintas fracciones de ella. Se postulan los mecanismos de formacion de los componentes volatiles de cada fraccion y los de las interacciones de las fases intermedias correspondientes a distintas fracciones. (author) [Russian] Obluchenie razlichnyh sortov mjasa s cel

  1. Biohydrogen production from diary processing wastewater by anaerobic biofilm reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rios-Gonzalez, L.J.; Moreno-Davila, I.M.; Rodriguez-Martinez, J.; Garza-Garcia, Y. [Universidad Autonoma de Coahuila, Saltillo, Coahuila (Mexico)]. E-mail: leopoldo.rios@mail.uadec.mx

    2009-09-15

    to be employed for hydrogen production. [Spanish] Este articulo describe la produccion biologica de hidrogeno a partir de agua residual diaria via fermentacion anaerobica utilizando choque termico pretratado (100 grados centigrados, 30 min.) y procedimientos de tratamiento acido para enriquecer selectivamente el hidrogeno produciendo consorcios mezclados antes de la inoculacion de reactores por lote. El biorreactor empleado para el consorcio de inmovilizacion se opero a temperatura mesofilica (ambiente) (20{+-}3 grados centigrados), bajo condiciones acidofilicas (pH 4.0-4.5), HRT (2h), y un soporte natural para generar hidrogeno produciendo biopelicula de consorcios mezclados: Opuntia imbricata. El reactor se opero inicialmente con sorbitol (5g/L) durante 60 dias de operacion. Las pruebas de lote se llevaron a cabo empleando 20{+-}0.02g de soporte natural con biopelicula. Los experimentos de lote se realizaron para investigar el efecto de la DQO ((2.9-21.1 g-DQO/L), a pH inicial de 7.0, 32{+-}1 grados centigrados. La produccion maxima de hidrogeno se obtuvo a 21.1 g-COD/L. Se efectuaron experimentos del efecto del pH empleando una concentracion de sustrato optima (21.2 g-COD/L), a pH de 4 a 7 y 11.32 (pH de agua residual diaria) y 32{+-}1 grados centigrados. Los resultados de los experimentos indican que el cultivo inicial optimo fue de pH 4.0, pero podemos considerar tambien una produccion estable de hidrogeno a pH 11.32 (pH de agua residual diaria), por lo que se pudo evitar ajustar el pH, y usar agua residual diaria como queda en el proceso de produccion de queso. El pH operacional de 4.0 esta 1.5 unidades por debajo del reportado antes correspondiente al hidrogeno que producen los organismos. La influencia del efecto de la temperatura se realizo usando la concentracion de sustrato optima (21.2 g-COD/L), dos niveles de pH: 4.0 y 11.32, y cuatro diferentes temperaturas: 16{+-}3 grados centigrados (temperatura ambiente), 32{+-}1 grados centigrados, 45{+-}1 grados

  2. Sensorial, biochemical and microbiological evaluations of guacamole, an avocado based product, under cold storage and added with ascorbic acidAvaliações sensoriais, bioquímicas e microbiológicas do guacamole, um produto à base de abacate, sob armazenamento a frio e com adição de ácido ascórbico

    Directory of Open Access Journals (Sweden)

    Lídia Raquel de Carvalho

    2011-07-01

    peroxidase (POD, EC 1.11.1.7 e polifenoloxidase (PPO, EC 1.10.3.1 do guacamole adicionado de ácido ascórbico e conservado sob frio elaborado, usando-se abacate da variedade Hass. Produtos acondicionados em embalagens de polietileno+nylon com e sem aplicação de vácuo foram submetidos ao congelamento lento e rápido (-18ºC e armazenados em freezer (-18ºC. Avaliações foram realizadas no momento da elaboração do produto (t0 e aos 3, 7 e 30 dias após armazenamento, sendo que no t30 as amostras foram mantidas sob refrigeração (4 ±1ºC e avaliadas após 3, 5 e 7 dias. Após 30 dias de armazenamento, a - 18ºC sob congelamento, seguido de descongelamento e mantendo-se à 4ºC±1 por 7 dias, as notas para os parâmetros sensoriais diminuram. A peroxidase foi totalmente inibida no produto elaborado e a atividade da enzima polifenoloxidase diminuiu consideravelmente no guacamole (20,07 mM de catecol/g massa fresca em relação ao fruto (58,31 mM de catecol/g massa fresca, porém sem variação significativa durante o armazenamento (à -18ºC. As amostras apresentaram-se microbiologicamente estáveis nas condições do estudo. A adição de acido ascórbico contribuiu para conservação do produto de abacate congelado diminuindo a atividade enzimática. No entanto, os parâmetros sensoriais são prejudicados com o descongelamento e armazenamento à 4±1oC.

  3. Use of radioisotopes in studying the penetration of sulphur into iron during hydrogen cathode charging; Application des radioelements a l'etude de la penetration du soufre dans le fer lors du chargement en hydrogene cathodique; Ispol'zovanie radioehlementov dlya izucheniya proniknoveniya sery v zhelezo, kogda ona zaryazhaetsya katodnym vodorodom; Aplicacion de los radioelementos al estudio de la penetracion del azufre en el hierro durante la carga con hidrogeno catodico

    Energy Technology Data Exchange (ETDEWEB)

    Besnard, S; Talbot, J [Centre National de la Recherche Scientifique, Vitry (France)

    1962-01-15

    soufre aux joints des grains. Ce resultat, qui ne pouvait etre obtenu qu'avec l'aide des radiotraceurs, a des consequences importantes notamment dans l'industrie des petroles. Une etude analogue a ete faite en utilisant le radioisotope 32 du phosphore. (author) [Spanish] Determinados elementos, como por ejemplo el arsenico, se emplean corrientemente en el laboratorio para fomentar la penetracion del hidrogeno en el hierro. Por otra parte, se ha comprobado en la industria que la presencia de acido sulfhidrico intensifica la corrosion de los aceros por el hidrogeno. Cabia preguntarse si estas sustancias, que hasta ahora se consideraban como catalizadores, solo fomentan la absorcion del hidrogeno, o si ejercen una influencia directa sobre el metal. Los autores han estudiado este fenomeno en su laboratorio con ayuda de hierro electrolitico puro. Han efectuado la sobresaturacion con hidrogeno por carga catodica. Como sustancia de adicion emplearon sulfuro de sodio marcado con azufre-35. Lograron demostrar que en media hora a la temperatura de -15 Degree-Sign C, el azufre penetra en el hierro hasta una profundidad de unas 120 {mu}m. Han podido comprobar ademas que el azufre se localiza preferentemente en los limites intergranulares. Este resultado, que solo pudo obtenerse gracias a los indicadores radiactivos, tiene importantes consecuencias, en especial para la industria del petroleo. Los autores han realizado un estudio analogo utilizando el radioisotopo 32 del fosforo. (author) [Russian] Nekotorye ehlementy, kak naprimer mysh'yak, obychno ispol'zovalis' v laboratorii dlya oblegcheniya proniknoveniya vodoroda v zhelezo. V promyshlennosti bylo ustanovleno, chto korroziya stalej, vyzvannaya prisutstviem vodoroda, usilivaetsya pri nalichii sernistogo vodoroda. Voznikal vopros, dopuskali li ehti veshchestva, rassmatrivaemye do sikh por v kachestve katalizatorov, tol'ko samuyu bol'shuyu absorbtsiyu ili okazyvali neposredstvennoe vozdejstvie na metall. Izuchenie ehtogo yavleniya

  4. Gamma-Ray-Initiated Graft Copolymerization on the Surface of Nylon Fibers and in the Inner Layers of Cellulosic Fibers; Amorcage par rayons gamma de la formation de copolymeres greffes a la surface de fibres de nylon et dans les couches internes de fibres cellulosiques; Sopolimerizatsionnoe narashchivanie na poverkhnosti nejlonovogo volokna i vo vnutrennikh sloyakh tsellyuloznykh volokon pod dejstviem gamma-izluchenij; Copolimerizacion por injerto radioinducida en la superficie de fibras de nylon y en las capas internas de fibras celulosicas

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, S; Iwasaki, T; Kobayashi, Y; Hayashi, K

    1960-07-15

    lorsque l'on fait gonfler les fibres cellulosiques dans du methanol contenant de 5 a 10 pour cent de formamide. Les auteurs ont etudie l'effet des concentrations de formamide et de styrolene en solution dans le methanol et ont constate que la greffage atteint son maximum lorsque le taux de concentration est de 5 pour cent pour le formamide et de 70 pour cent pour le styrolene. Pour des doses d'irradiation de l'ordre de 10{sup 5} r/h, ils ont constate que le taux de greffage etait fonction de la diffussion. (author) [Spanish] La irradiacion de fibras de nylon en una atmosfera de nitrogeno provoca la formacion de enlaces transversales, en tanto que la irradiacion en presencia del aire se traduce en una degradacion. Las alteraciones causadas por la irradiacion se estudiaron disolviendo las fibras irradiadas en acido sulfurico y midiendo la viscosidad de la solucion asi obtenida. Tambien se estudio la resistencia a la traccion de las fibras irradiadas en presencia de aire. Cuando el material se irradia en una atmosfera de nitrogeno para sumergirse luego en una solucion acuosa de acrilamida e irradiarse nuevamente, se observa que el injerto tiene lugar exclusivamente en la superficie de la fibra. Por el contrario, cuando la irradiacion previa se realiza en presencia del aire, el injerto se produce en las capas internas de las fibras. El polimero injertado puede localizarse por tincion de las fibras. La medida en que el estireno disuelto en metanol se injerta en la celulosa aumenta considerablement e cuando las fibras se sumergen previamente en una solucion del 5 al 10 por ciento de formamida en metanol. Se ha estudiado el efecto de la concentracion de formamida y de estireno en las soluciones de metanol, comprobandos e que el grado de injerto mas elevado se alcanza cuando la concentracion de formamida asciende a un 5 por ciento, y la de estireno a un 70 por ciento. Por otra parte, se ha llegado a la conclusion de que la difusion es el fenomeno que regula la velocidad de

  5. Tissue culture of Cecropia glaziovii Sneth (urticaceae: vegetative micropropagation and plant regeneration from callus Cultura de tecidos de Cecropia glaziovii Sneth (Urticaceae: micropropagação vegetativa e regeneração de plantas via calos

    Directory of Open Access Journals (Sweden)

    Marcos Nopper Alves

    2010-10-01

    ção de brotações múltiplas a partir de calos e a partir de brotos apicais. Folhas, pecíolos e estípulas obtidas de plântulas assépticas e da esterilização de sementes ou através da esterilização direta dos explantes foram utilizados para iniciar os cultivos. Brotações múltiplas foram obtidas quando brotos apicais ou axilares foram inoculados em meios compostos de sais de Murashige & Skoog (MS, suplementado com apenas 6-benzilaminopurine (BAP (1,0, 5,0 ou 10,0 mg L-1 ou combinado com ácido -naftaleno acético (ANA (1,0 ou 2,0 mg L-1, depois de 40 dias. A produção de calos foi obtida após 30 dias, quando pecíolos foram inoculados em meio MS acrescido de acido 2,4 diclorofenoxiacético (2,4-D (5,0 mg L-1 combinado com BAP (1,0 mg L-1. A regeneração de brotos a partir de calos foi obtida quando meio MS acrescido de apenas zeatina (ZEA (0,1 mg L-1 ou combinado com 2,4-D (1,0 ou 5,0 mg L-1 foi inoculado com calos friáveis obtidos de pecíolos. As plântulas foram enraizadas em MS suplementado com ácido 3-indol acético (AIA (1.0 mg L-1. A aclimatação das plântulas enraizadas foi estabelecida pela transferência para vasos contendo substrato orgânico e vermiculita sob umidade relativa 100%. As plântulas regeneradas "in vitro" apresentaram aparência normal e idênticas à planta-mãe. Nosso estudo concluiu que genótipos de elite de C. glaziovii podem ser propagados em larga escala através de métodos "in vitro", proporcionando uma fonte confiável de matéria prima para estudos farmacológicos.

  6. Tissue Metabolism of Tritium-Labelled Thyroid Hormones and Thyronine; Sur le Metabolisme Cellulaire d'Hormones Thyroiediennes Marquees par le Tritium; 0422 043a 0430 043d 0435 0432 044b 0439 043c 0414 ; Metabolismo de las Hormonas Tiroideas y de la Tironina Marcadas con {sup 3}H en los Tejidos

    Energy Technology Data Exchange (ETDEWEB)

    Roche, J.; Nunez, J.; Jacquemin, Cl. [Laboratoire de Biochimie Generale et Comparee, College de France, Paris (France)

    1962-02-15

    . La 3'-hydroxythyronine et la 3,4-dihydroxyphenylalanine dont la presence illustre la participation de processus d'o-hydroxylation dans le catabolisme des cycles. -3. Les acides thyroacetiques et p-hydroxyphenylacetique dont l'apparition repond au schema general de la degradation des acides a-amines. (author) [Spanish] La eliminacion de yodo de las hormonas tiroideas da origen a yoduros y a tironina (T{sub 0}) que el autor ha caracterizado en cortes de tejido o en un preparado de tiroxinodesyodasa. El autor aporta una prueba directa de este proceso: la 3, 5, 3'-triyodotironina y la 3, 3', 5'-triyodotironina, marcadas, respectivamente, en {alpha}, {beta} y en 3 con {sup 3}H conducen a la formacion de T{sub 0} y de otros compuestos en el rinon. La identificacion de la T{sub 0} como derivado natural de las hormonas tiroideas justificaba el estudio de su metabolismo en los tejidos; el autor incubo T{sub 0}, marcada en 3 y 5 con {sup 3}H, junto con cortes de rinon y de musculo. Por radiocromatografia con contador de centelleo liquido y por autorradiografia logro determinar: 1) Tirosina, cuya formacion constituye una prueba de la ruptura del puente difenileter de la T{sub 0}. 2) 3'-hydroxitironina y 3,4-dihidroxifenilalanina, compuestos cuya presencia indica que en el catabolismo de los cielos intervienen procesos de O-hidroxilacion. 3) Los acidos tiroacetico y p-hidroxifenilacetico, cuya aparicion concuerda con el esquema general de la degradacion de los a-aminoacidos. (author) [Russian] Obeziozhivanie shhitovidnyh gormonov vedet k obrazovaniju iodidov i tironina (T{sub 0}), harakternaja osobennost' kotoryh byla dostignuta na osnovanii tkanevyh razrezov ili prigotovlenija obeznozhennogo tiroksina. Privoditsja neposredst- vennoe dokazatel'stvo jetogo processa: 3,5 i 3's trehiodistym tironinom i 3. 3' i 5 s trehiodistym tironinom mechennyh sootvetstvenno i al'fa i beta luchami i 3 mechennogo tritiem, vedut, mezhdu prochim, k obrazovaniju v pochke tironina. Identifikacija

  7. Direct Measurement of Tritium in Biological Materials with the Liquid Scintillation Counter; Determination quantitative directe du tritium dans les substances biologiques, au moyen de compteurs a scintillations a liquides; Neposredstvennoe izmerenie kolichestva tritiya v biologicheskikh materialakh pri pomoshchi zhidkogo stsintillyatsionnogo schetchika; Determinacion cuantitativa directa del tritio en sustancias biologicas mediante contadores de centelleador liquido

    Energy Technology Data Exchange (ETDEWEB)

    Halvorsen, K [Institutt for Atomenergi, Kjeller, Lillestroem (Norway)

    1962-01-15

    muestras de tejidos de raton a los que se habia inyectado previamente timidina marcada con tritio. Despues de inyectar al raton una dosis del orden de 1 {mu}c de timidina tritiada por gramo de peso corporal, se pudieron seguir durante un mes las transformaciones metabolicas de la timidina incorporada al acido desoxirribonucleico (DISIA) de los distintos tejidos. (author) [Russian] V literature uzhe soobshchalos' o sposobakh izmereniya kolichestva tritiya v tkanyakh zhivotnykh i v izolirovannykh srezakh tkanej. Odnako pri vsekh opisyvaemykh rabotakh dlya otscheta impul'sov obraztsov primenyalsya zhidkostnyj stsintillyatsionnyj spektrometr sovpadenij. Pri vypolnenii nastoyashchej raboty dlya izmerenij byl ispol'zovan zhidkostnyj stsintillyatsionnyj schetchik s odnim fotoehlementom. Issledovalis' glavnym obrazom neposredstvennoe rastvorenie tkanej zhivotnykh v giamine 10-KH i otschet impul'sov vzvesi liofilirovannoj tkani v stsintilliruyushchikh gelyakh. Razlichnye tkani, kak naprimer, pechen', kishechnik, krov' i kozha mogut byt' neposredstvenno rastvoreny v giamine i aktivnost' ikh izmerena s tochnost'yu do 10-15 protsentov. Budut obsuzhdeny metody vvedeniya popravki na gashenie i nekotorye yavleniya fosforestsentsii, poskol'ku oni vliyayut na otschet impul'sov v schetnom ustrojstve s edinym fotoehlementom. KHotya chuvstvitel'nost' ehtogo metoda predstavlyaetsya neskol'ko men'shej, chem pri ispol'zovanii schetchika sovpadenij, odnako ehtot metod udovletvoritelen dlya mnogikh vidov primenenij. Predstavlyaemaya rabota byla provedena na obraztsakh tkanej myshi posle predvaritel'noj in{sup e}ktsii mechennogo tritiem timidina. Pri vpryskivanii v mysh' dozy priblizitel'no v 1 mikrokyuri tritirovannogo timidina na gramm vesa ee tela, metabolicheskaya sud'ba timidina, pogloshchennogo deoksiribonukleinovoj kislotoj razlichnykh tkanej, mogla byt' proslezhena v techenie tselogo mesyatsa. (author)

  8. Recent Radiochemical Procedures for Bio-Assay Studies at Trombay; Methodes Radiochimiques d'Analyse Biologique Employees a Trombay; Nedavno razrabotannye v trombee radiokhimicheskie metody dlya biologicheskikh issledovanij; Regientes Metodos Radioquimicos Aplicados al Analisis Biologico en Trombay

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, P. R.; Bhat, I. S.; Rudran, Kamala; Iyengar, M. A.R.; Koshy, Elizabeth; Waingankar, Urmila S.; Khanolkar, Vasanti S. [Health Physics Division, Atomic Energy Establishment Trombay, Bombay (India)

    1964-10-15

    travaux accomplis au laboratoire d'analyses biologiques depuis 1958. (author) [Spanish] El laboratorio de analisis biologicos de Trombay efectua anualmente cerca de dos mil analisis de orina para determinar diferentes radionuclidos, siendo los isotopos de mayor interes el {sup 232}Th, {sup 228}Th, {sup 226}Ra, {sup 224}Ra, {sup 228}Ra, U natural, productos de fision y {sup 239}Pu, asip como el {sup 60}Co, {sup 32}P, {sup 131}I, {sup 32}P, {sup 137}Cs, {sup 3}H, {sup 90}Sr, etc. El analisis rapido de un gran numero de muestras de baja actividad exige el perfeccionamiento de tecnicas especiales, sobre todo cuando se desea un alto grado de especificidad, unido a un elevado rendimiento. La' orina presenta una matriz muy complicada, con una elevada proporcion de sustancias organicas complejantes y contenido variable de sales. Los procedimientos de calcinacion por via humeda exigen un tiempo considerable y resultan engorrosos cuando se han de destruir muestras de aproximadamente 1 a 1,5 l. El trabajo deseribe algunos metodos recientemente desarrollados en el laboratorio de los autores y proporciona detalles de estudios sobre indicadores que han intervenido en el desarrollo de aquellos metodos. Radio-228: Se mide el mesotorio contenido en la orina despues de separar el {sup 228}Ac en equilibrio radiactivo. El radio presente en la orina se coprecipita con BaSO{sub 4}, teniendose en cuenta que sigue formandose {sup 228}Ac. El precipitado se disuelve en acido perclorico despues de anadir como portadores Pb, Bi y La. Los sulfatos insolubles se precipitan con H{sub 2}SO{sub 4} diluido y el {sup 228}Ac que permanece en solucion, despues de ser arrastrado con F{sub 3}La, se somete a recuento de actividad beta y se comprueba la disminucion de actividad. La cantidad de {sup 228}Ra se calcula a partir de la actividad observada en el {sup 228}Ac despues de introducir la oportuna correccion para tener en cuenta la desintegracion y el rendimiento de la recuperacion quimica. Torio: El trabajo

  9. Food Irradiation Research and Pilot Facilities in Operation or Planned in India; Recherches sur l'irradiation des Denrees Alimentaires et Installations Pilotes en Service ou a l'Etude en Inde; Izuchenie oblucheniya pishchevykh produktov' i dejstvuyushchie'i zaplanirovannye opytnye ustanovki v Indii; Irradiacion de Alimentos en la India: Investigaciones y Plantas Piloto en Servicio o en Proyecto

    Energy Technology Data Exchange (ETDEWEB)

    Kumta, U. S.; Sreenivasan, A. [Atomic Energy Establishment Trombay, Bombay (India)

    1966-11-15

    ventajas tecnologicas que ofrece el tratamiento por irradiacion gamma de alimentos de origen marino, habiendose analizado las propiedades organolepticas, la carga bacteriana, los indicios quimicos de descomposicion y las variaciones cualitativas y cuantitativas de la flora causante de la descomposicion. La radiopasteurizacion (0,4 Mrad) prolonga el periodo de almacenamiento del Harpodon neherens de Bombay hasta 21 dias, cuando se conserva a 10-12 Degree-Sign C, y hasta 45 dias, si se conserva a 0-4 Degree-Sign C, mientras que el mismo pescado sin irradiar se descompone rapidamente en tres dias. El tratamiento combinado consistente en calentamiento preliminar (4 min) seguido de irradiacion en pequena dosis (0,15 Mrad) prolonga el periodo de almacenamiento de los camarones hasta 90 dias, si se conservan a 0-4 Degree-Sign C. Si se suprime el calentamiento preliminar, los camarones se conservan bien durante 60 dias; los testigos no irradiados se descomponen en tres dias. Un tratamiento de deshidratacion-irradiacion, ideado para el Harpodon neherens de Bombay y los camarones, prolonga el periodo de almacenamiento de los productos semidesecados (40% de humedad) a la temperatura ambiente (25-28 Degree-Sign C) hasta 150 dias. Este tratamiento se ha estudiado en relacion con la dosis de irradiacion tolerada, el efecto sinergico del acido sorbico, el mejoramiento de la calidad por medio de otros tratamientos fisicos y quimicos y el tipo de envase. La aparicion de mohos y de olores desagradables por oxidacion en el queso puede retardarse hasta unos 20 dias a la temperatura ambiente mediante el empleo combinado de bajas dosis de irradiacion (0,1 y 0,2 Mrad) y de envolturas impregnadas de acido sorbico. Se han estudiado los danos causados por las radiaciones en proteinas de pez analizando el grado de escision y de agregacion, el efecto de desarrollo y la movilidad electroforetica. El empleo de las radiaciones para desinfestar cereales y prolongar el periodo de almacenamiento del pan de

  10. The extreme environments and their microbes as models for extraterrestrial life

    Science.gov (United States)

    Seckbach, J.; Oren, A.; Chela-Flores, J.

    2008-09-01

    Life exists almost everywhere on Earth. Presence of liquid water is a prerequisite for life (Oren, 2008). Living organisms are not only found in `normal' habitats (from the anthropocentric view). Many types, especially of microorganisms, not only tolerate harsh environmental conditions, but even thive in them. Such organisms that resist very harsh physical and chemical conditions in their habitats are termed `extremophiles'. Some extremophilic microorganisms are able to overcome more than one type of extreme conditions in their environment. For example, some `polyextremophiles' grow under hundreds of atmospheres of hydrostatic pressure (barophiles) and at very low, or alternatively at very high temperatures. In many hot springs there are acido-thermophiles that tolerate elevated temperatures and very low pH levels (e.g. the Cyanidium caldarium group, see Seckbach 1994). Members of Cyanidium are able to thrive in pure CO2, a condition not tolerated by most algae (Seckbach et al., 1970). Some thermophilic Archaea grow at temperatures up to 1130C and possibly even higher. In the Arctic and Antarctic regions and in the permafrost region in Siberia there are cold-loving microorganisms (psychrophiles) which are able to grow at -200C. Many types of Bacteria and Archaea tolerate extreme dryness, and spores of Bacillus and relatives that have been encapsulated within salt crystals may have survived in a dormant state for thousands and even millions of years, and still can be revived today. Other extremophiles tolerate salt concentrations up to saturation. Halophilic microorganisms such as found in the Dead Sea or in the Great Salt Lake have developed different strategies to cope with the high osmotic pressure of their environment. Some (e.g. the unicellular green alga Dunaliella salina) balance the salts in their medium by accumulating organic compounds such as glycerol. Others (halophilic Archaea of the order Halobacteriales, as well as a few representatives of the

  11. Review of the Status of Irradiation Effects on Citrus Fruits; Analyse des Effets de l'Irradiation sur les Agrumes; Obzor vliyaniya oblucheniya na plody tsitrusovykh; Examen de los Efectos de la Irradiacion en los Agrios

    Energy Technology Data Exchange (ETDEWEB)

    Dennison, R. A.; Ahmed, E. M. [University of Florida, Gainesville, FL (United States)

    1966-11-15

    precios de venta al por menor corrientes en 1959-1963, se ha calculado que en los Estados Unidos las perdidas por deterioro de naranjas y pomelos ascienden a 8,4 y 5,4 millones de dolares, respectivamente. La putrefaccion del pedunculo y las prodredumbres verde y cardena son las que causan mayores perdidas por descomposicion en los agrios despues de la recoleccion. No es posible administrar una sola dosis de irradiacion que baste para proteger a los agrios contra la descomposicion. Para retardar infecciones antiguas o arraigadas se necesitan dosis de irradiacion mayores que para retardar las infecciones incipientes. En la lucha contra las infecciones por irradiacion gamma influye tanto la intensidad del flujo como la magnitud de la dosis. Los agrios frescos sufren alteraciones metabolicas que terminan por provocar la senescencia. En algunos casos, estas alteraciones comprenden variaciones de la actividad respiratoria, del contenido de acidos organicos, azucares y sustancias icticas, asi como de la coloracion. Los efectos de los danos producidos por las radiaciones son parecidos en muchos aspectos a la perdida de vitalidad celular en la senescencia. La irradiacion produce modificaciones en los componentes pecticos de los frutos. En general, aumentan las fracciones de agua y de oxalato amonico soluble y disminuye la fraccion de hidroxido sodico soluble. El zumo exprimido de frutos irradiados presenta un gran aumento de la pectina soluble en agua. Al parecer, este aumento se debe a la afluencia de pectina soluble en agua proveniente de otras partes del fruto. El resultado es un neto incremento de la viscosidad del zumo. A raiz de la irradiacion y almacenamiento del fruto se observan a veces lesiones de la piel. La proporcion de frutos que presentan estas lesiones y la gravedad de las mismas aumentan con la temperatura y la duracion del almacenamiento. Las naranjas y los pomelos pueden irradiarse con dosis de hasta 200 krad sin que se aprecien efectos perjudiciales en sus

  12. The Origin and Nature of Radioactive Wastes in the United States Atomic Energy Programme; Origine et Nature des Dechets Radioactifs de l'Execution des Programmes d'Energie Atomique aux Etats-Unis; 041f 0420 041e 0418 0421 0425 041e 0416 0414 ; Origen y Naturaleza de los Desechos Radiactivos en el Programa de Energia Atomica de los Estados Unidos

    Energy Technology Data Exchange (ETDEWEB)

    Bruce, F. R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1960-07-01

    clases de desechos: desechos de actividad media, que resultan de la disolucion quimica, y contienen el 0,1 per ciento, aproximadamente, del total de los productos de fision, y desechos de actividad elevada, que contienen el resto de los productos de fision en una solucion diluida de acido nitrico. El volumen de los desechos evaporados varia entre 0,8 1 per kilogramo de uranio, para los combustibles poco enriquecidos y 500 1 por kilogramo de uranio, para los muy enriquecidos, se prove que la industria nuecleoelectrica de los Estados Unidos producira como termino medio unos 5 1 de desechos de actividad elevada y media por kilogramo de uranio utilizado. En los Estados Unidos se calcula que para 1970 esta industria habra producido unos 3 x 10{sup 9} curies disueltos en un volumen de 2,7 x 10{sup 7} l y 6 x 10{sup 10} curies en 1,1 x 10{sup 9} l de solucion para el ano 2000. Los desechos procedentes de los reactores generadores plantean, por razon de su composicion, nuevos problemas de almacenamiento y evacuacion. (author) [Russian] Sostav othodov, obrazuemyh pri jekspluatacii reaktorov, zavisit, vo-pervyh, ot obrabotki, kotoraja primenjaetsja pri vosproizvodstve toplivnyh jelementov, i, vo-vtoryh, ot pervonachal'nogo sostava toplivnyh jelementov. Pri obrabotki s primeneniem jekstrakcii vodnyh rastvorov vysokaja, srednjaja i nizkaja aktivnost' othodov voznikaet v priblizitel'nom ob'emnom sootnoshenii, ravnom odnomu, pjati i 100 sootvetstvenno. Othody, voznikajushhie v rezul'tate vosproizvodstva vysokoobogashhennyh toplivnyh jelementov, byvajut bol'shimi po ob{sup e}mu, tak kak oni soderzhat toplivnyj razbavitel'. Nizkoobogashhennye toplivnye jelementy obychno sostojat iz uranovoj serdceviny, pokrytoj aljuminiem, cirkoniem ili nerzhavejushhej stal'ju ; jeti jelementy dajut dva vida othodov. Pervye othody srednej stepeni aktivnosti, soderzhashhie okolo 0,1% produktov raspada, voznikajut v rezul'tate himicheskogo rastvorenija. Vtoroj vid othodov s vysokoj stepen'ju aktivnosti

  13. Studies on the Influence of Tritium Radiation on Anaerobic Bacteria from the Bovine Rumen; Influence de l'Irradiation par le Tritium sur les Bacteries Anaerobies du Rumen des Bovins; 0418 0441 0414 ; Estudios sobre los Efectos de las Radiaciones del Tritio en las Bacterias Anaerobias de la Panza de los Bovinos

    Energy Technology Data Exchange (ETDEWEB)

    Brueggemann, J.; Giesecke, D. [Institute of Physiology and Animal Nutrition, University of Munich, Munich, Federal Republic of Germany (Germany)

    1962-02-15

    flore au repos a 0 Degree-Sign C, la dose totale etant d'environ 300 krads en 20 jours; cependant, il est difficile de repeter l'experience dans des conditions identiques par suite de l'heterogeneite de la substance. D'autres experiences ont ete faites sur des cultures pures de souches choisies de bacteries du rumen. Des doses allant jusqu'a 150 krads en 5 jours n'ont eu aucune influence marquee sur la croissance anaerobie et le metabolisme des hydrates de carbones. Toutefois, en presence d'oxygene pendant l'irradiation de cellules au repos, on a note une forte reduction du nombre des bacteries viables. On a constate que l'oxygene exercait un effet letal sur ces especes, suivant un ordre de decroissance logarithmique. On suppose que l'action de T{sub 2}O sur ces microorganismes prives de catalase est surtout attribuable aux produits secondaires d'irradiation, notamment a H{sub 2}O{sub 2}. Cependant, il reste encore a obtenir quelques resultats qui corroboreraient cette hypothese. (author) [Spanish] La flora bacteriana presente en la panza de los bovinos se compone en su mayoria de especies estrictamente anaerobias que proveen al huesped de grandes cantidades de acidos grasos volatiles (AGV), como principal fuente de energia. Dicha flora se ha sometido a irradiaciones prolongadas in vitro, utilizando T{sub 2}O, en una ''panza artificial'', en condiciones anaerobias, y se ha observado que las dosis de hasta 75 krad no ejercen efecto inhibitorio alguno sobre la proliferacion de las bacterias ni sobre la produccion de AGV. Despues de irradiar la flora en reposo a 0 Degree-Sign C con una dosis total de unos 300 krad durante 20 dias, se observaron efectos estimulantes que se traducen en una aceleracion de la division celular y en un aumento de la cantidad de AGV, pero, dada la heterogeneidad del material empleado, resulta dificil repetir el experimento en igualdad de condiciones. Se han realizado otros ensayos con cultivos puros de cepas seleccionadas de bacterias de la panza

  14. Development of Radiation-Sterilized Sea Food Products. I. Enzyme-Inactivated Cod and Halibut Patties; Essais de Radiosterilisation des Produits Alimentaires d'Origine Marine. I. Pates de Morue et de Fletan a Enzymes Inactives; Primenenie izlucheniya dlya sterilizatsii morskikh pishchevykh produktov; Preparacion de Alimentos de Origen Marino Esterilizados por Irradiacion. I. Pastelillos de Bacalao y de Hipogloso con Enzimas Inactivadas

    Energy Technology Data Exchange (ETDEWEB)

    Sinnhuber, R. O.; Landers, Mary K.; Yu, T. C. [Department of Food Science And Technology, Oregon State University, Corvallis, OR (United States); Simon, M.; Heiligman, F. [United States Army Natick Laboratories, Natick, MA (United States)

    1966-11-15

    baflo de agua hirviente. Despues de dejarlas enfriar durante un dfa, para que las proteinas se asentasen, se cortaron en pastelillos de 3/8 pulg. de espesor, se envasaron en latas y se sometieron a una dosis de irradiacion de 4,5 Mrad. Los productos radioesterilizados se almacenaron durante 12 meses a 72 Degree-Sign F, y se sometieron a examenes periodicos para evaluar la calidad y el efecto de varios tratamientos. Los tratamientos que se aplicaron fueron: envasado al vacfo, adicion de varios antioxidantes y empleo de paquetes de carbon vegetal. Antes de servirlos, los pastelillos fueron rebozados en besamela y empanados, y se frieron bien. La coniestibilidad de los pastelillos se estudio por medio de grupos de catadores y de mediciones objetivas, tales como contenido total de bases volatiles, fndice de acido 2-tiobarbiturico, pH e indice de reflectancia cromatica. El sabor de los productos recibio puntuaciones aceptables de grupos de catadores (140 a 170 personas) durante 12 meses'de almacenamiento a 72 Degree-Sign F. Aunque los catadores prefirieron las muestras testigo no irradiadas a los productos irradiados, todos los pastelillos irradiados almacenados puntuaron en la parte positiva de la escala hedonfstica de 9 puntos. Los indices de reflectancia cromatica de los productos alimenticios marinos radioesterilizados pueden utilizarse para medir el dorado producido por la irradiacion y parecen guardar correlacion con la duracion del almacenamiento. (author) [Russian] Byli prigotovleny lepeshki iz treski (Gadus macrocephalus) i paltusa (Hippoglossus steno- lepsis), sterilizovannye s pomoshh'ju obluchenija i inaktivirovannye v otnoshenii dejstvija jenzimov, kotorye javljajutsja perspektivnymi s kommercheskoj tochki zrenija. Oni prigotavlivajutsja putem smeshenija razmel'chennoj ryby s beloj kukuruznoj mukoj, zhelatinom i sol'ju, posle chego jetoj smesi pridaetsja forma kolbasok. Inaktivacija jenzimov dostigaetsja posredstvom nagrevanija kolbasok v vanne s kipjashhej

  15. Solidification of Radioactive Waste Solutions; Solidification des Effluents Radioactifs; 041e 0422 0412 0415 0420 0416 0414 0415 041d 0418 0415 0420 0410 0414 0418 041e 0410 041a 0422 0418 0412 041d 042b 0425 0421 0411 0420 041e 0421 041d 042b 0425 0420 0410 0421 0422 0412 041e 0420 041e 0412 ; Solidificacion de Efluentes Radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Brezhneva, N. E.; Golovanov, Ju. N.; Oziraner, S. N.; Eremin, A. A.; Rozanova, V. N.

    1963-02-15

    hierro obtenido por precipitacion de las soluciones radiactivas iniciales. El procedimiento de solidificacion se elaboro con miras a reducir al minimo el volumen de los gases de escape que requieren una depuracion en raaon de la presencia de aerosoles y de componentes radiactivos volatiles. En el curso del trabajo los autores determinaron las condiciones optimas de preparacion de un vidrio quimicamente estable y demostraron la posibilidad de disminuir la temperatura de fusion del vidrio modificando la proporcion de fundentes agregados. Comprobaron que la estabilidad quimica del vidrio disminuye apreciablemente si se lo almacena durante largo tiempo a una temperatura superior a 300 Degree-Sign -350 Degree-Sign C. Estudiaron la medida en que el radiocesio corre el riesgo de ser extraido del vidrio por lixiviacion e investigaron la volatilidad del radiocesio y del radiorrutenio en el proceso de desecacion y fusion demostrando que la volatilidad del rutenio desaparece totalmente en atmosfera de anhidrido carbonico. La volatilidad del radiocesio adquiere valores apreciables a temperaturas superiores a los 700 Degree-Sign C y se intensifica al ascender la temperatura. Se observo que el radiocesio se condensa en la paredes de las tuberias de evacuacion por debajo de los 400 Degree-Sign C, pudiendo eluirse facilmente con una solucion diluida de acido nitrico en agua. Un calculo del calor desprendido en loe vidrios radiactivos indica que el radio de una esfera de vidrio que contenga un material de elevada radiactividad (10 c/g) no debe exceder de los 25 cm. Los autores presentan un esquema de las distintas fases del procedimiento de desecacion y vitrificacion de sustancias radiactivas basado en la utilizacion de refrigerantes gaseosos. Describen ademas los aparatos necesarios para llevar a cabo la operacion de moldeo. (author) [Russian] Izlagajutsja rezul'taty laboratornoj razrabotki metoda otverzhdenija radioaktivnyh sbrosnyh rastvorov, osnovannogo ka sushke i osteklovyvajaii

  16. Reactions of Hot Tritium Atoms with Amino Acids; Reactions entre Atomes Chauds de Tritium et Acides Amines; Reaktsii goryachikh atomov tritiya s aminokislotami; Reacciones de Atomos de Tritio Calientes con Aminoacidos

    Energy Technology Data Exchange (ETDEWEB)

    Simonov, E. F.; Nesmejanov, An. N. [Moskovskij Gosudarstvennyj Universitet, Moskva, SSSR (Russian Federation)

    1965-04-15

    de la structure des composes (longueur de la chaine, groupes de substitution fonctionnels). Les auteurs ont etudie le rendement des reactions entre atomes chauds de tritium et acides amines: 1. lorsque la chaine des acides amines s'allonge; 2. lorsque les acides amines ont une chaine carbonee de longueur identique mais possedent des groupes de substitution fonctionnels differents. A cette fin, ils ont irradie des melanges de carbonate de lithium et d'acides a etudier dans un flux de neutrons lents de 0,87 * 10{sup 13}n/cm{sup 2} * s, pendant 15 min. L'analyse a ete faite au moyen d'un appareil de chromatographie gazeuse sur colonne a supports interchangeables (tamis moleculaires, huile de vaseline sur terre d'infusoires) et par chromatographie sur papier. Les donnees obtenues sur la survie a l'irradiation des acides amines en fonction de la longueur de la chaine carbonee semblent contredire une regle fondamentale de radiochimie, selon laquelle la duree de conservation des molecules augmente avec l'allongement de leur chaine, mais elles peuvent s'expliquer par un transfert intramoleculaire de l'excedent d'energie le long de la chaine carbonee - du point d'impact de l'atome chaud au groupe hydroxyle - et la dissipation consecutive de cet excedent; en revanche, bien que l'energie des atomes de tritium de recul depasse l'energie de liaison chimique, cette derniere agit malgre tout sur la conservation des molecules qui ont une chaine carbonee de meme longueur, mais possedent des groupes de substitution differents. (author) [Spanish] Las obras publicadas hasta la fecha no contienen datos sistematicos sobre la interaccion de los atomos de retroceso de tritio con aminoacidos. Tales datos, en conjuncion con los resultados obtenidos para los acidos organicos y las aminas, podrian ayudar a establecer el mecanismo de las reacciones de atomos calientes referido a la estructura de los compuestos (longitud de la cadena, naturaleza de los grupos funcionales). Los autores

  17. Hanford High-Level Waste Management; Gestion des Dechets de Haute Activite a Hanford; 041e 0411 0420 0410 0411 041e 0422 041a 0410 0412 042b 0421 041e 041a 041e 0420 0410 0414 0418 041e 0410 041a 0422 0418 0412 041d 042b 0425 041e 0422 0425 041e 0414 041e 0412 0412 0425 042d 041d 0424 041e 0420 0414 0415 ; Tratamiento y Evacuacion de Desechos de Elevada Radiactividad en Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Tomlinson, R. E. [Hanford Laboratories, General Electric Co., Richland, WA (United States)

    1963-02-15

    tanques subterraneos. Como esta operacion solo se considera provisional, se esta llevando activa mente a la practica un programa encaminado a reducir la movilidad de los materiales almacenados a fin de mejorar el confinamiento a largo plazo. En los actuales tanques subterraneos, se evaporaran hasta obtener tortas de sal grandes volumenes de desechos de desenvainado que en esencia no son autocalentadores. Los estudios de laboratorio y los primeros ensayos efectuados en un tanque de 5 000 gal demuestran que el paso de una corriente de aire caliente a traves de la solucion, junto con una carbonatacion controlada para transformar elhidroxidodesodio libre en carbonato de sodio, permite eliminar bastante agua para formar una torta de sal no higroscopica. Los desechos auto- calentadores se fraccionaran para poder almacenar por separado los emisores de periodo largo en pequenos recipientes de gran solidez. Estos materiales podrian aprovecharse en casos especiales. Despues de que los emisores autocalentadores de periodo corto se hayan ''friado''urante 5 a 10 a, los desechos salinos residuales se combinaran con los desechos corrientes de desvainado y se evaporaran para formar tortas de sal. Para llevar a cabo el tratamiento quimico necesario, se estan introduciendo ciertas modificaciones en un antiguo edificio con pasillos blindados. Probablemente se recurrira a la extraccion por solvente (D2EHPA) para separar el estroncio y el cerio de los desechos acidos; aun no se ha decidido si la aislacion del cesio se efectuara mediante extraccion por solventes, el intercambio ionico o la precipitacion. Se confia que la operacion completa podra llevarse a cabo alrededor de 1966. (author) [Russian] Za 17 let v Hjenforde dostignuta vysokaja stepen' bezopasnosti hranenija vysokoradioaktivnyh othodov v vide shhelochnyh shlammov v podzemnyh bakah pri sravnitel'no nevysokoj stoimosti. V nastojashhee vremja osushhestvljaetsja programma sokrashhenija podvizhnosti hranimyh materialov dlja dostizhenija

  18. Pathogenia da anemia na Ancylostomose: II - causas determinantes dos phenomenos regenerativos e degenerativos nessa anemia e contribuições para elucidar o seu mechanismo intimo Pathogenesis of Anaemia in Hookworm Disease: II - causes wich determine the regenerative and degenerative phenomena in this anaemia and contributions towards the elucidation of their inmost mechanism

    Directory of Open Access Journals (Sweden)

    W. O. Cruz

    1934-12-01

    ausentes, os normoblastos, as hematias com restos nucleares e as hematias polychromaticas. A reticulose oscilla em torno de 3%. Este aspecto é constante nos casos graves, sendo entretanto variavel na unidade de volume o numero destas hematias acima caracterisadas. A média dessa ultima cifra em numerosos casos é de 2,50 M., o que determina uma taxa de Hb. egual a 23%. Ao analysarmos certas observações, que descrevem aspectos hematologicos differentes daquelles aqui descriptos, concluimos pela existencia nesses casos anomalos, de superposições de outras doenças, cuja etio-pathogenia nada tem a ver com os factores que determinam o apparecimento da anemia ancylostomotica. A regeneração hematica processa-se na Ancylostomose unicamente após a administração de ferro em dóses variaveis, conforme o sal empregado. Mostraram-se inactivas nos casos aqui observados, as administrações de figado crú, triptophano, hystidina, lecithina, Vit. B, saes de arsenico, manganez, cobalto, cobre e a alimentação com dietas ricas em ferro. Em virtude dos resultados que obtivemos com a administração isolada de ferro, concluimos pela inefficiencia da administração de substancias pyrrholicas, da fracção hepatica sensivel nas anemias hypochromicas, e da associação ao ferro de acido chlorhydrico. Todas essas substancias, e tambem a elimanação simples dos helminthos parasitos, não só mostraram-se isoladamente sem acção sobre o sangue, como não auxiliaram a regeneração provocada pelo ferro...We studied 25 selected cases of anchylostomiasis, endeavouring to determine the factors which induce the hematic regeneration and investigating the mechanism of this regeneration as well as the development of the anemiant process. We preferred to select a small number of cases and accompany them for a long period, some of them having been underobservation during 1 to 1 year and a half. Apart from 568 routine examinations (count of red cells, dosage of Hb., determination of the

  19. The Combined Use of Autoradiographic and Electron Microscopic Techniques for Studies on Ultra-Thin Sections of Tritium-Labelled Cells of the Intestinal Epithelium; Emploi Combine de l'Autoradiographie et du Microscope Electronique pour L'Etude de Coupes Ultra-Fines de Cellules Tritiees de l'Epithelium Intestinal; 0421 043e 0432 043c 0435 0414 ; Empleo Combinado de Tecnicas de Autorradiografia y de MicroscopiA Electronica para Estudiar Cortes Ultrafinos de Celulas Tritiadas del Epitelio Intestinal

    Energy Technology Data Exchange (ETDEWEB)

    Hampton, J. C. [Division of Experimental Biology, Baylor University College of Medicine, TX (United States); Quastler, H. [Brookhaven National Laboratory, Upton, Long Island, NY (United States)

    1962-02-15

    dans la cellule. Les travaux presentes dans ce memoire demontrent qu'il est possible d'etudier au microscope electronique des coupes ultrafines de cellules marquees, de recuperer l'echantillon apres avoir pris des micrographies electroniques convenables, de l'enduire d'une emulsion suffisamment epaisse pour obtenir une autoradiographie, mais tout de meme assez mince pour permettre un nouvel examen au microscope electronique et obtenir des images micrographiques des autoradiographies deja faites. L'emulsion autoradiographique a ete appliquee comme suit: formation d'une mince pellicule sur une petite boucle de fil metallique plongee dans l'emulsion liquide, puis transfert de la pellicule par passage de la boucle sur l'echantillon monte, fixe a l'extremite d'une chevillette en plastique. On peut effectuer un controle satisfaisant en prenant, lorsqu'on fait les coupes, une coupe d'un demimicron apres chaque coupe ultrafine en la montant sur une lamelle de verre et en appliquant les techniques autoradiographiques classiques. En raison de la fragilite des coupes ultrafines, le nombre d'autoradiographies reussies est tres faible. Malgre cet inconvenient, on peut esperer qu'avec une plus grande experience et un perfectionnement des techniques, cette methode aidera a mieux comprendre les processus des cellules vitales. (author) [Spanish] Merced al elevado grado de resolucion que puede alcanzarse actualmente por observacion de cortes de celulas en el microscopio electronico, resulta posible estudiar algunos de los procesos intracelulares que conducen a la sintesis de las proteinas. La especificidad de la incorporacion de timidina tritiada en la molecula de acido desoxirribonucleico permite seguir detenidamente el desarrollo del proceso en funcion del tiempo y su localizacion dentro de la celula. Los trabajos descritos en la presente memoria demuestran que es po