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Sample records for chemical substances by ph

  1. Structure of Bacterial Extracellular Polymeric Substances at Different pH Values as Determined by SAXS

    OpenAIRE

    Dogsa, Iztok; Kriechbaum, Manfred; Stopar, David; Laggner, Peter

    2005-01-01

    Extracellular polymeric substances (EPS) play an important role in cell aggregation, cell adhesion, and biofilm formation, and protect cells from a hostile environment. The EPS was isolated by trichloroacetic acid/ethanol extraction from broth culture of a marine bacterium isolate. The EPS was composed of glucose and galactose as determined by HPLC and TLC; the protein content was on average 15 ± 5% of EPS dry mass. The solution structure of EPS at different values of pH was revealed by small...

  2. Risks and Chemical Substances.

    Science.gov (United States)

    Blumberg, Avrom A.

    1994-01-01

    Examines exposure to chemicals within the home and three important ways in which hazardous substances can be identified and evaluated. Suggests a rational picture of human health risks and contains an introductory discussion of reasons for exposure, epidemiology, cancer causes and patterns, animal testing, toxins, and risk. (LZ)

  3. The Focus and Substance of Formative Comment Provided by PhD Examiners

    Science.gov (United States)

    Holbrook, Allyson; Bourke, Sid; Fairbairn, Hedy; Lovat, Terence

    2014-01-01

    In practice and process PhD examination is distinctive, reflecting the high expectations of students whose learning has been directed to their becoming researchers. This article builds on previous research on the examination of Australian theses that revealed that examiners in Science (n?=?542) and Education (n?=?241) provide a substantial…

  4. Indoor air pollution by chemical substances; Kagaku busshitsu ni yoru shitsunai kuki osen

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, T. [National Institute of Hygienic Sciences, Tokyo (Japan)

    1995-07-31

    The economy in our country entered the high growth period in the 1960,s, and specially the chemical industry based on fossil fuel brought about raped development. This was accompanied by widespread amicability of construction materials and household articles made from chemical substances in offices and households. As a results of the first oil crisis in 1973, energy conservation has since been intended, particularly the amount of ventilation in the office was reduced to about 1/3-1/4 of that in Europe and America. Accordingly, many working people in office have complained of various symptoms such as headache and dizziness. It subsequently became clear that the causes were hazardous pollutants in the room. From the above point of view, we focused on air pollution in terms of chemical substances in the room(office and living environment) in this paper. We introduce the present state of air pollution in the room with reference to the results of our studies and literature inside and outside the country. 35 refs., 10 tabs.

  5. Excitation by irritant chemical substances of sensory afferent units in the cat's cornea.

    Science.gov (United States)

    Belmonte, C; Gallar, J; Pozo, M A; Rebollo, I

    1991-01-01

    1. Single-unit electrical activity was recorded from thin myelinated sensory nerve fibres innervating the cornea of deeply anaesthetized cats. 2. Based on their responses to mechanical (calibrated von Frey hairs), chemical (10 mM-acetic acid and/or 616 mM-NaCl) and thermal (ice-cold or heat up to 51 degrees C) stimuli, corneal A delta fibres were classified as polymodal nociceptors (63%), high-threshold mechanoceptors (22%) and mechano-heat nociceptors (15%). Thin myelinated fibres responding only to cold were found in the limbus of the eye. 3. Application of 10 mM-acetic acid on the corneal surface for 30 s evoked in polymodal fibres a brisk discharge of impulses often followed by a low-frequency impulse activity. NaCl (616 mM) produced a more gradual and sustained firing response. 4. The responses of polymodal fibres to acid were proportional to extracellular pH values (pH range: 4.5-6.0). After sensitization to repeated heating, most mechano-heat units developed a sensitivity to acidic stimulation. 5. Topical 0.33 mM-capsaicin excited polymodal nociceptors of the cornea; 5 min after capsaicin about 15% of these fibres were inactivated to all subsequent stimuli. In the rest of the fibres, chemical and thermal sensitivity disappeared after 0.33-3.3 mM-capsaicin, but mechanosensitivity was preserved. 6. Corneal mechanoceptors and limbal cold receptors were not affected by capsaicin (up to 33 mM). 7. These experiments demonstrate that the cornea of the cat is innervated by polymodal as well as mechanoceptive A delta nociceptors. In polymodal nociceptive fibres, mechanical and chemical sensitivities appear to be subserved by separate transduction mechanisms. PMID:1890657

  6. Brain temperature and pH measured by 1H chemical shift imaging of a thulium agent

    OpenAIRE

    Coman, Daniel; Trubel, Hubert K.; Rycyna, Robert E.; Hyder, Fahmeed

    2009-01-01

    Temperature and pH are two of the most important physiological parameters and are believed to be tightly regulated because they are intricately related to energy metabolism in living organisms. Temperature and/or pH data in mammalian brain are scarce, however, mainly due to lack of precise and non-invasive methods. At 11.7T, we demonstrate that a thulium-based macrocyclic complex infused through the blood stream can be used to obtain temperature and pH maps of rat brain in vivo by 1H chemical...

  7. Short-column anion-exchange chromatography for soil and peat humic substances profiling by step-wise gradient of high pH aqueous sodium ethylenediaminetetraacetate.

    Science.gov (United States)

    Hutta, Milan; Ráczová, Janka; Góra, Róbert; Pessl, Juraj

    2015-08-21

    Novel anion-exchange liquid chromatographic method with step gradient of aqueous EDTA(4-) based mobile phase elution has been developed to profile available Slovak soil humic substances and alkaline extracts of various soils. The method utilize short glass column (30mm×3mm) filled in with hydrolytically stable particles (60μm diameter) Separon HEMA-BIO 1000 having (diethylamino)ethyl functional groups. Step gradient was programmed by mixing mobile phase composed of aqueous solution of sodium EDTA (pH 12.0; 5mmolL(-1)) and mobile phase constituted of aqueous solution of sodium EDTA (pH 12.0, 500mmolL(-1)). The FLD of HSs was set to excitation wavelength 480nm and emission wavelength 530nm (λem). Separation mechanism was studied by use of selected aromatic acids related to humic acids with the aid of UV spectrophotometric detection at 280nm. The proposed method benefits from high ionic strength (I=5molL(-1)) of the end mobile phase buffer and provides high recovery of humic acids (98%). Accurate and reproducible profiling of studied humic substances, alkaline extracts of various types of soils enables straightforward characterization and differentiation of HSs in arable and forest soils. Selected model aromatic acids were used for separation mechanism elucidation. PMID:26143606

  8. Aqueous media treatment and decontamination of hazardous chemical and biological substances by contact plasma

    International Nuclear Information System (INIS)

    Usage of non-equilibrium contact plasma for processes of decontamination and neutralization in conditions of manifestation of chemical, biological and radiation terrorism takes on special significance due to portability of equipment and its mobility in places where toxic liquid media hazardous for people's health are located. Processes of decontamination of aqueous media, seminated with pathogenic microorganisms and viruses, treatment of water containing toxic heavy metals, cyanides, surface-active substances, and heavy radioactive elements, are investigated. Examples of activation processes in infected water and toxic aqueous solutions present convincing evidence of the way, how new quality technological approach for achievement of high enough degree of the said media treatment is used in each specific case. Among new properties of water activated as a result of action of non-equilibrium contact plasma, it is necessary to mention presence of cluster structure, confirmed by well-known spectral and physical-chemical methods, presence of peroxide compounds, active particles and radicals. Anti-microbial activity which is displayed under action of plasma in aqueous media (chemically pure water, drinking water, aqueous solutions of sodium chloride, potassium iodide, as well as other inorganic compounds) towards wide range of pathogenic and conventionally pathogenic microorganisms allows use them as reliable, accessible and low-cost preparations for increasing the degree of safety of food products. Combination of such processes with known methods of filtration and ultra-filtration gives an efficient and available complex capable of withstanding any threats, which may arise for population and living organisms. Present-day level of machine-building, electrical engineering, and electronics allows predict creation of industrial plasma installations, adapted to conditions of various terrorist threats, with minimized power consumption and optimized technological parameters

  9. pH effect on the synthesis of magnetite nanoparticles by the chemical reduction-precipitation method

    OpenAIRE

    Ângela L. Andrade; Diana M. Souza; Márcio C. Pereira; José D. Fabris; Rosana Z. Domingues

    2010-01-01

    This work aimed at putting in evidence the influence of the pH on the chemical nature and properties of the synthesized magnetic nanocomposites. Saturation magnetization measurements evidenced a marked difference of the magnetic behavior of samples, depending on the final pH of the solution after reaction. Magnetite and maghemite in different proportions were the main magnetic iron oxides actually identified. Synthesis with final pH between 9.7-10.6 produced nearly pure magnetite with little ...

  10. Physical-chemical characterization and stability study of alpha-trypsin at ph 3.0 by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Santos, A.M.C.; Santana, M.A.; Gomide, F.T.F.; Oliveira, J.S.; Vilas Boas, F.A.S.; Santoro, M.M.; Teixera, K.N. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Biologicas (ICB). Dept. de Bioquimica e Imunologia; Miranda, A.A.C.; Biondi, I. [Universidade Estadual de Feira de Santana (UEFS), BA (Brazil). Dept. de Ciencias Biologicas; Vasconcelos, A.B.; Bemquerer, M.P. [EMBRAPA Recursos Geneticos e Biotecnologia, Brasilia, DF (Brazil). Parque Estacao Biologica (PqEB)

    2008-07-01

    Full text: {alpha}-Trypsin is a serine-protease with a polypeptide chain of 223 amino acid residues and six disulfide bridges. It is a globular protein with predominance of antiparallel {beta}-sheet secondary structure and it has two domains with similar structures. In the present work, a stability study of {alpha}-trypsin in the acid pH range was performed and physical-chemical denaturation parameters were measured by using differential scanning calorimetry (DSC). The {alpha}-trypsin has a shelf-life (t{sub 95%}) of about ten months at pH 3.0 and 4 deg C and its hydrolysis into the {psi}-trypsin isoform is negligible during six months as monitored by mass spectrometry (Micromass Q-ToF). The observed {delta}H{sub cal}/{delta}H{sub vH} ratio is close to unity for {alpha}-trypsin denaturation, which suggests the occurrence of a two-state transition, devoid of molten-globule intermediates. At pH 3.0, {alpha}-trypsin unfolded with T{sub m} 325.9 K and {delta}H= 99.10 kcal mol{sup -1}, and the change in heat capacity between the native and unfolded forms of the protein was estimated to be 1.96 {+-} 0.18 kcal mol{sup -1} K{sup -1}. The stability of {alpha}-trypsin calculated at 298 K and at pH 3.0 was {delta}G{sub U} = 6.10 kcal mol{sup -1}. These values are in the range expected for a small globular protein. These results show that the thermodynamic parameters for unfolding of {beta}-trypsin do not change substantially after its conversion to {alpha}-trypsin.

  11. Physical-chemical characterization and stability study of alpha-trypsin at ph 3.0 by differential scanning calorimetry

    International Nuclear Information System (INIS)

    Full text: α-Trypsin is a serine-protease with a polypeptide chain of 223 amino acid residues and six disulfide bridges. It is a globular protein with predominance of antiparallel β-sheet secondary structure and it has two domains with similar structures. In the present work, a stability study of α-trypsin in the acid pH range was performed and physical-chemical denaturation parameters were measured by using differential scanning calorimetry (DSC). The α-trypsin has a shelf-life (t95%) of about ten months at pH 3.0 and 4 deg C and its hydrolysis into the Ψ-trypsin isoform is negligible during six months as monitored by mass spectrometry (Micromass Q-ToF). The observed ΔHcal/ΔHvH ratio is close to unity for α-trypsin denaturation, which suggests the occurrence of a two-state transition, devoid of molten-globule intermediates. At pH 3.0, α-trypsin unfolded with Tm 325.9 K and ΔH= 99.10 kcal mol-1, and the change in heat capacity between the native and unfolded forms of the protein was estimated to be 1.96 ± 0.18 kcal mol-1 K-1. The stability of α-trypsin calculated at 298 K and at pH 3.0 was ΔGU = 6.10 kcal mol-1. These values are in the range expected for a small globular protein. These results show that the thermodynamic parameters for unfolding of β-trypsin do not change substantially after its conversion to α-trypsin

  12. Effect of pH, ionic strength, foreign ions and humic substances on Th(IV) sorption to GMZ bentonite studied by batch experiments

    International Nuclear Information System (INIS)

    Bentonite has been studied extensively because of its strong sorption and complexation ability. Herein, GMZ bentonite from Gaomiaozi county (Inner Mongolia, China) was investigated as the candidate of backfill material for the removal of Th(IV) ions from aqueous solutions. The results indicate that the sorption of Th(IV) is strongly dependent on pH and ionic strength at pH 5. Outer-sphere surface complexation or ion-exchange are the main mechanism of Th(IV) sorption on GMZ bentonite at low pH values, whereas the sorption of Th(IV) at pH > 5 is mainly dominated by inner-sphere surface complexation or surface precipitation. Soil fulvic acid (FA) and humic acid (HA) have a positive influence on the sorption of Th(IV) on bentonite at pH < 5. The different addition sequences of HA and Th(IV) to GMZ bentonite suspensions have no obvious effect on Th(IV) sorption to HA-bentonite hybrids. The high sorption capacity of Th(IV) on GMZ bentonite suggests that the GMZ bentonite can remove Th(IV) ions from large volumes of aqueous solutions in real work. (author)

  13. Chemical Experiments Measuring ph and Gases on "Planetary" Soil by the HUSAR-5 NXT-based Rover Model

    Science.gov (United States)

    Lang, Agota; Bérczi, Szaniszló; Erdélyi, Soma; Nickl, Istvan; Kiss, Daniel; Erdősi, Ferenc; Panyi, Tamas; Szalay, Kristof

    2010-05-01

    Introduction: We report two chemical experiments studying the soil on the surface of a planet. Both experiments are built on the HUSAR-5 rover model (Hungarian University Surface Analyser Rover) in a Hungarian high school. In the first experiment our rover uses optical lens as classical heating experiment and gas-sensor to measure the chemical components liberated by the heating. In the second experiment we measure chemical characteristics of the soil by using the indicator method. We report the constructions and experiments carried out by our rover. The task of the first mission: The main goal of the experiment is to move and fix the lens so that the plane of the lens should be perpendicular to the axis of the incident solar light. It is important that the focus of the lens should reach the soil exactly, and it should be operated at any incidence position. We solved this problem using three motors. Two move the lens around horizontal axes, and the third one around a vertical one. The technological structure of HUSAR-5 instruments has been built from LEGO elements, driven by LEGO Mindstorms motors and controlled by NXT "brain". We used a photoresistor, whose signal was lead into the NXT. The steps of the measuring process are the followings I. For focusing: 1. Basic position: The lens is in resting position exactly a focus distance above the soil. The holding arm is horizontal, and the plane of the lens is also horizontal, parallel to the soil. 2. After selecting the location of the measurement, the NXT first moves the lens and finds the position (with the help of the lightsensor) where the intensity of the light is the largest. 3. The other motor moves the arm up and down and positions the lens plane perpendicular to the solar lights. The program takes into the memory both measured angles. 4. The forth step is lifting up the arm into the necessary position. From the initial position the lifting motor states the arm to this position which is calculated by the

  14. Cytotoxic substances produced by a fungal strain from a sponge: physico-chemical properties and structures.

    Science.gov (United States)

    Amagata, T; Usami, Y; Minoura, K; Ito, T; Numata, A

    1998-01-01

    Five novel metabolites, trichodenones A-C (1-3), harzialactone A (4) and B (5), have been isolated together with known R-mevalonolactone (6) from the culture broth of a strain of Trichoderma harzianum OUPS-N115 originally separated from the sponge Halichondria okadai. Their structures have been elucidated by spectral evidence. Among them, 1-3 exhibited significant cytotoxicity against cultured P388 cells. PMID:9531985

  15. Atividade alelopática de substâncias químicas isoladas da Acacia mangium e suas variações em função do PH Allelopathic activity of chemical substances isolated from Acacia mangium and its variations in function of PH

    Directory of Open Access Journals (Sweden)

    S.M. Luz

    2010-01-01

    Full Text Available Os objetivos deste trabalho foram isolar, identificar e caracterizar a atividade alelopática de substâncias químicas produzidas por Acacia mangium, além de determinar as variações na atividade das substâncias em função da variação do pH da solução. A atividade alelopática foi avaliada em bioensaios de germinação (25 ºC de temperatura e fotoperíodo de 12 horas e crescimento de radícula e hipocótilo (25 ºC de temperatura e fotoperíodo de 24 horas das plantas daninhas malícia (Mimosa pudica e mata-pasto (Senna obtusifolia. Avaliou-se a interferência do pH (3,0 e 9,0 da solução na atividade alelopática das substâncias sobre a germinação das sementes da espécie malícia. Os triterpenoides lupenona (3-oxolup-20(29-eno e lupeol (3β-hidroxilup-20(29-eno, obtidos das folhas caídas da planta doadora, isolados e em par, evidenciaram baixo efeito alelopático inibitório da germinação de sementes e do crescimento do hipocótilo, especialmente do primeiro, cujos efeitos não ultrapassaram o valor de 2,0%. Os efeitos promovidos sobre o crescimento da radícula foram de maior magnitude, atingindo valores superiores a 40%, com destaque para as inibições promovidas pela substância lupenona. Isoladamente, as substâncias promoveram efeitos superiores aos efetivados pelas substâncias analisadas em pares, indicando a existência de antagonismo. O pH da solução influenciou a atividade alelopática das substâncias; para lupenona os efeitos foram mais intensos em pH ácido, enquanto para lupeol os melhores resultados foram verificados em condições alcalinas, mostrando que este fator é ponto importante a ser considerado em trabalhos de campo.The aim of this study was to isolate, identify and characterize the allelopathic activity of the substances produced by Acacia mangium and to determine the variations of this activity according to the pH variation of the solution. The allelopathic activity was evaluated in germination

  16. Effect of pH and dissociation on the fate and exposure of ionizable chemicals

    DEFF Research Database (Denmark)

    Franco, Antonio; Trapp, Stefan

    2010-01-01

    Ionizable organic chemicals comprise an important fraction of pharmaceuticals, pesticides as well as industrial chemicals. It has been estimated that 33% of the preregistered REACH substances is mostly ionized at pH 7. To extend the appliccability of existing exposure models, a Multimedia Activity...... Model for Ionics (MAMI) was recently developed and tested. In the present study, the impact of the parameters describing ionization was assessed by performing the sensitivity and the uncertainty analysis on MAMI for the acids 2,4-D, pentachlorophenol, bisphenol-A, perfluorooctanoic acid and the bases...... parameters. The sensitivity analysis showed that the parameters describing ionization, pH and the dissociation constant (pKa), are among the most sensitive model parameters. The uncertainty analysis, however, indicated that these parameters are not the major source of uncertainty, which statistically...

  17. 76 FR 75794 - Significant New Use Rules on Certain Chemical Substances; Withdrawal of Two Chemical Substances

    Science.gov (United States)

    2011-12-05

    ... notices (PMNs), i.e., rutile, tin zinc, calcium-doped (PMN P-06-36; CAS No. 389623-01-2) and rutile, tin zinc, sodium-doped (PMN P-06-37; CAS No. 389623-07-8). These chemical substances are subject to TSCA... withdrawing the rules issued for rutile, tin zinc, calcium-doped (PMN P-06-36; CAS No. 389623-01-2) and...

  18. Chemical substances as risk factors of nephropathy in diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Zofia Marchewka

    2009-12-01

    Full Text Available Although diabetes mellitus, a metabolic disease, does not fall into the group of diseases induced by toxic substances or environmental pollution, there is much evidence that some chemicals have considerable importance in its development. Exposure to substances with potential renal toxicity is especially dangerous for diabetics because it accelerates and intensifies diabetic nephropathy. This paper discusses the relationship between the xenobiotics and the development of diabetes mellitus and diabetic nephropathy with particular emphasis on those substances that causes the greatest damage to the kidneys. These are cadmium, iron, lead, arsenic, polychlorinated organic compounds, nitrogen compounds, and contrast agents. In addition, the mechanisms of diabetes mellitus induction or kidney damage by these xenobiotics are described.

  19. Effects of pH value and coagulant dosage on contact filtration of humic substances

    Institute of Scientific and Technical Information of China (English)

    蒋绍阶; 刘宗源; 梁建军

    2009-01-01

    Humic substances (especially fulvic acid (FA)) are the major components of natural organic matter (NOM) that widely exist in drinking water source. Due to their potential effects on public health,the removal of FA was one of the main concerns during the water treatment. Therefore,the contact filtration of FA by using aluminum sulfate as coagulant on the basis of jar tests was carried out. The effects of pH and coagulant dosage on the FA removal and the development of head loss were investigated. The results show that the range of pH value during the FA contact filtration can be effectively influenced by the dosage of aluminum sulfate,and the high aluminum sulfate dosage is an important factor that can result in early filter breakthrough. The FA filtration by deep-bed filtration or by membrane filtration is sometimes disparate under the same coagulation conditions. The choice of aluminum sulfate dosage by the method of membrane filtration,i.e. the "true color measurement",may result in inappropriate filter run,whereas it can be determined with simple jar tests by observing the formation of micro flocs. Considering the effects of pH on aluminum sulfate dosage and FA removal,the optimal pH range of 5.5?6.0 is suggested.

  20. Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution

    Science.gov (United States)

    Sandoval-Paz, M. G.; Rodríguez, C. A.; Porcile-Saavedra, P. F.; Trejo-Cruz, C.

    2016-07-01

    Copper (I) selenide thin films with orthorhombic and cubic structure were deposited on glass substrates by using the chemical bath deposition technique. The effects of the solution pH on the films growth and subsequently the structural, optical and electrical properties of the films were studied. Films with orthorhombic structure were obtained from baths wherein both metal complex and hydroxide coexist; while films with cubic structure were obtained from baths where the metal hydroxide there is no present. The structural modifications are accompanied by changes in bandgap energy, morphology and electrical resistivity of the films.

  1. Removal of low level of 239+240Pu in aqueous solution between pH 2-6 by calcium alginate and its variation with aquatic humic substance

    International Nuclear Information System (INIS)

    During this work laboratory simulated experiments were carried out for the removal of low level of 239+240Pu from the aqueous solution. Water samples after filtering through 0.22 mm filter paper were spiked with 250 Bq/1 of 239+240Pu as Pu(NO3)4. The pH of the solutions were controlled between 2-6 by using 0.01M NaOH/HNO3. Spiked samples were kept in the argon atmosphere for a week. The spiked water is passed separately through 20 cm column having about 4 gm of calcium alginate beads. Calcium-alginate beads were prepared by immobilising 2% sodium alginate in 0.2 M calcium chloride solution. At different pH about 95-98% Pu was retained in the beads and significant variation was not observed at pH range studied. To understand the impact of dissolved organic substance on the absorption characteristics of Pu(IV) on calcium-alginate beads, about 0.01% (weight/volume) humic acid solution was mixed in the ratio of 1-4/100 (V/V) experimental solutions. It was observed that the presence of organic matter decreased the absorption by 40% which clearly indicate the complexation of Pu(IV) with humic acid, which was not further forming complex within the alginate beads. The various physicochemical characteristics were measured before and after passing the solution. About 40% of Pu is recovered from sodium alginate beads by using 0.1 M HNO3. (author)

  2. Occupational exposure to airborne chemical substances in paintings conservators

    Directory of Open Access Journals (Sweden)

    Anna Jeżewska

    2014-02-01

    Full Text Available Background: This paper presents the results of the quantitative study of the airborne chemical substances detected in the conservator's work environment. Material and Methods: The quantitative tests were carried out in 6 museum easel paintings conservation studios. The air test samples were taken at various stages of restoration works, such as cleaning, doubling, impregnation, varnishing, retouching, just to name a few. The chemical substances in the sampled air were measured by the GC-FID (gas chromatography with flame ionization detector test method. Results: The study results demonstrated that concentrations of airborne substances, e.g., toluene, 1,4-dioxane, turpentine and white spirit in the work environment of paintings conservators exceeded the values allowed by hygiene standards. It was found that exposure levels to the same chemical agents, released during similar activities, varied for different paintings conservation studios. It is likely that this discrepancy resulted from the indoor air exchange system for a given studio (e.g. type of ventilation and its efficiency, the size of the object under maintenance, and also from the methodology and protection used by individual employees. Conclusions: The levels of organic solvent vapors, present in the workplace air in the course of painting conservation, were found to be well above the occupational exposure limits, thus posing a threat to the worker's health. Med Pr 2014;65(1:33–41

  3. The chemical substances and the neurotoxic effect on workers

    Directory of Open Access Journals (Sweden)

    Rosa Morales

    2013-12-01

    Full Text Available (Received: 2013/10/02 - Accepted: 2013/12/13Tens of thousands of workers are exposed to pollution by the neurotoxicity found in their different workplaces, small businesses, handcrafting industries and even at home. The problem gets worst due to the lack of information on the risks posed by these substances and the safety controls to be taken during its use, on the other hand, the overconfidence that exists about the abstraction of this danger when it comes to the exposure to small doses of toxicity by ignoring the cumulative effects of these substances every time they enter the body. In Ecuador, nowadays there are few studies that distinguish this exposure to these substances, and none on the incidence of the neurotoxic syndrome, considering it an important field to research. Workers who are exposed to chemical toxic substances are now associated to adverse human health effects, due to its aggression and because of the worker´s safety before breaking health directly. They enter the body by the respiratory, dermal or digestive system, and show a great affinity with the body grease so that it accumulates and affects the different organs, tissues, the central nervous system, the bone marrow and liver. Immediate acute and chronic long-term effects were detected due to the intensity and duration of the exposure. Some symptoms include drowsiness, loss of appetite, headache, dizziness, depression, anxiety, nervousness, fatigue, irritability, memory problems, mental sluggishness, apathy, seizures, motor skills incoordination, genetic alterations, among others.

  4. Effect of Ph on the Physical Properties of ZnIn2Se4 Thin Films Grown by Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    P. Babu

    2011-01-01

    Full Text Available ZnIn2Se4 (ZIS due to its potential applications in various fields, particularly as a buffer layer in the fabrication of heterojuction solar cells. In the present work, thin films of ZIS have been synthesized by a simple and economic method, chemical bath deposition at different pH values that vary from 9 to 11. The deposition was carried out for a fixed bath temperature (Tb of 90 °C and constant reaction time of 60 min. Ammonia and hydrazine hydrate were used as complexing agents. The chemical and physical properties of the deposited ZIS films were analyzed using appropriate techniques. The X-ray diffraction analysis revealed that the deposited films were polycrystalline and showed (112 peak as the preferred orientation. Scanning electron micrographs revealed that the samples had large number of granule like particles in different sizes. The optical transmittance of these samples was found to be > 75 % in the visible region and the evaluated energy band gap varied from 2.15 eV to 2.64 eV with the change of pH value in the range, 9 - 11. The detailed study of these results were presented and discussed.

  5. Developments of segregation process and chemical analysis for virus receptor recognizing environmental signal substance by affinity binding assaying

    International Nuclear Information System (INIS)

    Virus receptors recognizing environmental signal were segregated and analyzed chemically by affinity binding assaying using radio-isotope marked compound. Pathogenic protein in rice stem virus was indicated possibility of a protein which participates in transfer process between the virus cells. An enzyme, Chitobiose was separated from a bacteria, actinomycete. It was cleared by 3H chitobiose affinity binding assaying that two kinds of chitobiose binding protein existed in cell membrane of the actinomycete. A different kind of protein was founded in the cell membrane which was raised in existence of chitobiose. Observation showed that the protein was different from a protein in the cell membrane which was raised in non-existence of chitobiose. These two kinds of protein might be formed a complex compound on the surface of cell membrane. (M. Suetake)

  6. Removal of humic substances by biosorption

    Institute of Scientific and Technical Information of China (English)

    VUKOVI(C) Marija; DOMANOVAC Tomislav; BRI(S)KI Felicita

    2008-01-01

    Fungal pellets of Aspergillus niger 405, Aspergillus ustus 326, and Stachybotrys sp. 1103 were used for the removal of humic substances from aqueous solutions. Batchwise biosorption, carried out at pH 6 and 25℃, was monitored spectrophotometrically and the process described with Freundlich's model. Calculated sorption coefficients K/and n showed that A. niger exhibited the highest efficiency. A good match between the model and experimental data and a high correlation coefficient (R2) pointed out to judicious choice of the mechanism for removal of humic substances from the reaction medium. The sorption rate constants (k) for A. ustus and Stachybotrys sp. were almost equal, however higher than that for A. niger. Comparison of test results with the simulated ones demonstrated the applicability of the designed kinetic model for removal of humic substances from natural water by biosorption with fungal pellets. Different morphological structure of the examined fungal pellets showed that faster sorption does not imply the most efficient removal of humic substances. Desorption of humic substances from fungal pellets was complete, rapid, and yielded uniform results.

  7. Flows of Chemical Substances in Latvian Pine Forests Ecosystems

    OpenAIRE

    Tērauda, Evija

    2008-01-01

    FLOWS OF CHEMICAL SUBSTANCES IN LATVIAN PINE FORESTS ECOSYSTEMS Annotation As a basis of the study, data from integrated monitoring stations of Latvia have been used. The objective of the study is to study turnover of substances in ecosystems of pine forests in the boreo-nemoral zone. The results of the study showed that the mean concentration of studied elements (except Pb) increased in the order: bulk precipitation

  8. 77 FR 75390 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2012-12-20

    ..., automotive coating, wastewater treatment, solid waste. CAS number: 1392095-50-9. Chemical substance definition: The waste solids produced from the treatment of wastewaters from automotive pretreatment... amount of the substances reasonably likely to be removed from the waste stream by such treatment may...

  9. Chemical leasing business models: a contribution to the effective risk management of chemical substances.

    Science.gov (United States)

    Ohl, Cornelia; Moser, Frank

    2007-08-01

    Chemicals indisputably contribute greatly to the well-being of modern societies. Apart from such benefits, however, chemicals often pose serious threats to human health and the environment when improperly handled. Therefore, the European Commission has proposed a regulatory framework for the Registration, Evaluation and Authorization of Chemicals (REACH) that requires companies using chemicals to gather pertinent information on the properties of these substances. In this article, we argue that the crucial aspect of this information management may be the honesty and accuracy of the transfer of relevant knowledge from the producer of a chemical to its user. This may be particularly true if the application of potentially hazardous chemicals is not part of the user's core competency. Against this background, we maintain that the traditional sales concept provides no incentives for transferring this knowledge. The reason is that increased user knowledge of a chemical's properties may raise the efficiency of its application. That is, excessive and unnecessary usage will be eliminated. This, in turn, would lower the amount of chemicals sold and in competitive markets directly decrease profits of the producer. Through the introduction of chemical leasing business models, we attempt to present a strategy to overcome the incentive structure of classical sales models, which is counterproductive for the transfer of knowledge. By introducing two models (a Model A that differs least and a Model B that differs most from traditional sales concepts), we demonstrate that chemical leasing business models are capable of accomplishing the goal of Registration, Evaluation and Authorization of Chemicals: to effectively manage the risk of chemicals by reducing the total quantity of chemicals used, either by a transfer of applicable knowledge from the lessor to the lessee (Model A) or by efficient application of the chemical by the lessor him/herself (Model B). PMID:17958507

  10. Arsenic redox transformation by humic substances and Fe minerals

    Energy Technology Data Exchange (ETDEWEB)

    Kappler, Andreas, E-mail: andreas.kappler@uni-tuebingen.de [Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen (Germany); Amstaetter, Katja [Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen (Germany); Borch, Thomas [Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523-1170 (United States)] [Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1170 (United States); Larese-Casanova, Philip; Jiang Jie; Bauer, Iris [Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen (Germany); Paul, Andrea [IGB, Institute of Freshwater Ecology and Inland Fisheries, Mueggelseedamm 301, 12587 Berlin (Germany)

    2011-06-15

    Highlights: > As(III) oxidation by reduced humic substance model quinone (AQDS) containing semiquinone radicals. > As(III) oxidation by reactive Fe(II)-goethite systems. > Potential explanation for the presence of As(V) in reduced groundwater aquifers. - Abstract: The toxicity and mobility of the redox-active metalloid As strongly depends on its oxidation state, with As(III) (arsenite) being more toxic and mobile than As(V) (arsenate). It is, therefore, necessary to know the biogeochemical processes potentially influencing As redox state to understand and predict its environmental behavior. The first part of this presentation will discuss the quantification of As redox changes by pH-neutral mineral suspensions of goethite [{alpha}-Fe{sup III}OOH] amended with Fe(II) using wet-chemical and synchrotron X-ray absorption (XANES) analysis (). First, it was found that goethite itself did not oxidize As(III). Second, in contrast to thermodynamic predictions, Fe(II)-goethite systems did not reduce As(V). However, surprisingly, rapid oxidation of As(III) to As(V) was observed in Fe(II)-goethite systems. Iron speciation and mineral analysis by Moessbauer spectroscopy showed rapid formation of {sup 57}Fe-goethite after {sup 57}Fe(II) addition and the formation of a so far unidentified additional Fe(II) phase. No other Fe(III) phase could be detected by Moessbauer spectroscopy, EXAFS, scanning electron microscopy, X-ray diffraction or high-resolution transmission electron microscopy. This suggests that reactive Fe(III) species form as an intermediate Fe(III) phase upon Fe(II) addition and electron transfer into bulk goethite but before crystallization of the newly formed Fe(III) as goethite. The second part of the presentation will show that semiquinone radicals produced during microbial or chemical reduction of a humic substance model quinone (AQDS, 9,10-anthraquinone-2,6-disulfonic acid) can react with As and change its redox state (). The results of these experiments showed

  11. Data showing chemical compositions of the essential oils of the leaves of Cymbopogon citratus obtained by varying pH of the extraction medium.

    Science.gov (United States)

    Ajayi, E O; Sadimenko, A P; Afolayan, A J

    2016-09-01

    This article describes the various chemical components as obtained from the oils in the leaves of Cymbopogon citratus using hydrodistillation and solvent-free microwave extraction methods. Furthermore, extractions of the oils were also carried out with a slight in pH variation and compared, "GC-MS evaluation of C. citratus (DC) Stapf oil obtained using modified hydrodistillation and microwave extraction methods" (Ajayi et al., 2016 [1]). The current article contains one table exhibiting a list of compounds in the four different methods of extraction. Comparative studies amongst the various methods of extraction are highlighted in the table. PMID:27419197

  12. Shape control of cadmium hydroxides (Cd(OH)2) sensitive to pH quenching depth and massive production of CdSe nanocrystals by their chemical transformation

    International Nuclear Information System (INIS)

    This study demonstrates that the structure of cadmium hydroxides (Cd(OH)2) precipitated from a basic cadmium nitrate solution can be finely controlled by adjusting the pH of the precursor solution. The synthesis process involves only pouring the saturated solution into pure water to quench the pH and the total process is finished within 30 s. At a shallow pH quenching, the unstable nanoparticles turned into microparticles via a ripening process. Cd(OH)2 was precipitated in the form of one-dimensional nanowires and then two-dimensional plates as the pH quenching was increased. At a large pH quenching, porous aggregates of Cd(OH)2 were obtained due to the too fast precipitation. The ultrafine Cd(OH)2 nanowires were readily transformed into CdSe chain-like nanocrystals. The transformation was quick and gave 100% yield, facilitating massive production of CdSe nanocrystals in an aqueous condition. The Cd(OH)2 nanowires were directly grown on Si nanowires and transformed into CdSe chain-like nanocrystals, decorating the surface of each Si nanowire.

  13. Analysis of determination modalities concerning the exposure and emission limits values of chemical and radioactive substances

    International Nuclear Information System (INIS)

    This document presents the generic approach adopted by various organizations for the determination of the public exposure limits values to chemical and radioactive substances and for the determination of limits values of chemical products emissions by some installations. (A.L.B.)

  14. The Matthew effect in environmental science publication: A bibliometric analysis of chemical substances in journal articles

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Eriksen, Mette Lindholm; Ellegaard, Ole;

    2011-01-01

    publication rates. The persistence in the scientific literature of the top-20 chemicals was only weakly related to their publication in journals with a high impact factor, but some substances achieved high citation rates. Conclusions The persistence of some environmental chemicals in the scientific literature......Background While environmental research addresses scientific questions of possible societal relevance, it is unclear to what degree research focuses on environmental chemicals in need of documentation for risk assessment purposes. Methods In a bibliometric analysis, we used SciFinder to extract...... Chemical Abstract Service (CAS) numbers for chemicals addressed by publications in the 78 major environmental science journals during 2000-2009. The Web of Science was used to conduct title searches to determine longterm trends for prominent substances and substances considered in need of research...

  15. Probing the chemical steps of nitroalkane oxidation catalyzed by 2-nitropropane dioxygenase with solvent viscosity, pH, and substrate kinetic isotope effects.

    Science.gov (United States)

    Francis, Kevin; Gadda, Giovanni

    2006-11-21

    Among the enzymes that catalyze the oxidative denitrification of nitroalkanes to carbonyl compounds, 2-nitropropane dioxygenase is the only one known to effectively utilize both the neutral and anionic (nitronate) forms of the substrate. A recent study has established that the catalytic pathway is common to both types of substrates, except for the initial removal of a proton from the carbon of the neutral substrates [Francis, K., Russell, B., and Gadda, G. (2005) J. Biol. Chem. 280, 5195-5204]. In the present study, the mechanistic properties of the enzyme have been investigated with solvent viscosity, pH, and kinetic isotope effects. With nitroethane or ethylnitronate, the kcat/Km and kcat values were independent of solvent viscosity, consistent with the substrate and product binding to the enzyme in rapid equilibrium. The abstraction of the proton from the alpha carbon of neutral substrates was investigated by measuring the pH dependence of the D(kcat/KNE) value with 1,1-[2H2]-nitroethane. The formation of the enzyme-bound flavosemiquinone formed during catalysis was examined by determining the pH dependence of the kcat/Km values with ethylnitronate and nitroethane and the inhibition by m-nitrobenzoate. Finally, alpha-secondary kinetic isotope effects with 1-[2H]-ethylnitronate were used to propose a non-oxidative tautomerization pathway, in which the enzyme catalyzes the interconversion of nitroalkanes between their anionic and neutral forms. The data presented suggest that enzymatic turnover of 2-nitropropane dioxygenase with neutral substrates is limited by the cleavage of the substrate CH bond at low pH, whereas that with anionic substrates is limited by the non-oxidative tautomerization of ethylnitroante to nitroethane at high pH. PMID:17105207

  16. A wearable fingernail chemical sensing platform: pH sensing at your fingertips.

    Science.gov (United States)

    Kim, Jayoung; Cho, Thomas N; Valdés-Ramírez, Gabriela; Wang, Joseph

    2016-04-01

    This article demonstrates an example of a wearable chemical sensor based on a fingernail platform. Fingernails represent an attractive wearable platform, merging beauty products with chemical sensing, to enable monitoring of our surrounding environment. The new colorimetric pH fingernail sensor relies on coating artificial nails with a recognition layer consisted of pH indicators entrapped in a polyvinyl chloride (PVC) matrix. Such color changing fingernails offer fast and reversible response to pH changes, repeated use, and intense color change detected easily with naked eye. The PVC matrix prevents leaching out of the indicator molecules from the fingernail sensor toward such repeated use. The limited narrow working pH range of a single pH indicator has been addressed by multiplexing three different pH indicators: bromothymol blue (pH 6.0-7.6), bromocresol green (pH 3.8-5.4), and cresol red (pH 7.2-8.8), as demonstrated for analyses of real-life samples of acidic, neutral, and basic character. The new concept of an optical wearable chemical sensor on fingernail platforms can be expanded towards diverse analytes for various applications in connection to the judicious design of the recognition layer. PMID:26838451

  17. Stability and mobility of cerium oxide nanoparticles in soils: effects of humic substances, pH and ionic strength

    Science.gov (United States)

    Chen, Yirui; Mu, Linlin; Li, Chunyan; Bai, Lingyun; Jacobson, Astrid; Darnault, Christophe

    2015-04-01

    Among the large number of types of nanomaterials used in the field of nanotechnology, cerium oxide nanoparticles (CeO2 NPs) are among the top five most commonly utilized by industry, agriculture and nanomedicine for their unique physico-chemical properties. They are used, for example, in the production of catalysts, as fuel additives, and as polishing agents. Therefore, the release and encounter of CeO2 NPs in the environment following their application, waste disposal, life-cycle and accidents is inevitable. It is critical to examine the behavior of CeO2 NPs released in the environment to assess the risk they pose to the environmental and public health. In particular, little is known about the fate and transport of CeO2 NPs in soils and groundwater. To assess the behavior of CeO2 NPs, it is important to investigate the factors that affect their stability and mobility. Humic substances are a major component of soils and have been shown to have the potential to impact the transport and retention of nanoparticles in soils. Consequently, our study characterizes the impacts of humic and fulvic acids on the stability and mobility of cerium oxides in model porous media under various pH and ionic strength conditions. Batch experiments conducted at various concentrations of humic and fulvic acids coupled with a wide range of pHs and ionic strengths were investigated. Selected parameters from these batch studies were then used as experimental conditions representative of environmental systems to perform column transport experiments to assess of the mobility of CeO2 NPs in saturated porous media, which is the first step in simulating their behavior in soil and groundwater systems.

  18. Influence of pH on Chemical Forms of Phosphate Adfsorbed on Gothite Surfaces

    Institute of Scientific and Technical Information of China (English)

    LIUFAN; WANGDIAN-FEN; 等

    1995-01-01

    Chemical forms of the phosphate adsorbed on goethite surfaces and characteristics of the coordinate groups which exchange with P on goethite surfaces in solutions with different pll values were investigated.Results showed that the chemical forms of P on goethite surfaces changed from the dominance of monodentate corrdination to that of bidentate one with increasing pH of the solution.By influencing types of phosphate ions in solutions,pH affected the chemical forms of P on goethite surfaces,The amount of OH- displaced by phosphae on goethite surfaces was the most at pH 7.0,the second at pH 9.0,and the least at pH 4.5.

  19. Risk communication about chemical substance. Case studies in communication under guidelines established by local autonomies and trend of information sources; Kagaku busshitsu ni kansuru risuku komyunikeshon. Jichitai seitei no shishin ni motozuku komyunikeshon jirei to johogen no doko

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimi, H. [Kanagawa Environmental Research Center, Kanagawa (Japan)

    1995-01-10

    Actions and measures is left to local autonomies, to chemical substances that are in commercial markets and are out of national regulations for their emission and disposal, even though they have public concerns for environmental effects. Thus, a trend to establish guidelines to prevent pollution by those chemicals has been spreading among autonomies facing actions and measures to them. Present status and problems are explained, of the guideline establishment and communication between autonomies and citizens or business owners to promote their self-management according to guidelines. Further, recent trends are introduced, of information sources on chemical substances that serve as a base of the communication. Guidelines of some prefectures ask business owners to collect information on substances that they deal with and needs environmental attention, by a format mimicking to MSDS (Material Safety Data Sheet). On the other hands, other guidelines stipulate that prefectures should provide business owners with information in forms of data-book, off-line or on-line data-base to aid them to collect information. Some guidelines stipulate to settle agreements or to organize councils on environmental safety. 6 refs., 2 figs., 1 tab.

  20. Risk Assessment of New Chemical Substances: System Realisation and Validation II

    OpenAIRE

    Toet C; de Nijs ACM; Vermeire TG; Poel P van der; Tuinstra J

    1991-01-01

    In the project "Evaluation System new substances", methods are developed to systematically predict and assess the hazards for man and environment related to the production and use of new chemical substances. Part of the project is the realisation of a Risk Assessment System for New Chemical Substances, which is described in this report. This system is a computer program, available for advisory tasks concerning the assessment of hazard and risk of new chemical substances (level 0). A...

  1. Aquatic toxicity of forty industrial chemicals: Testing in support of hazardous substance spill prevention regulation

    Science.gov (United States)

    Curtis, M. W.; Ward, C. H.

    1981-05-01

    The U.S. Environmental Protection Agency is presently developing hazardous substance spill regulations to help prevent water pollution. Aquatic animal toxicity data are used as criteria for the designation and categorization of substances as hazardous, even though this type of data is not available for many industrial chemicals. Static 96-hr. toxicity tests were conducted with 40 such chemicals to provide basic toxicity data for regulatory decision making. Thirty-two of the 40 chemicals tested were hazardous to aquatic life as determined by 96-hr. LC 50's less than or equal to 500 mg/l. All 40 chemicals were tested with the fresh-water fathead minnow, Pimephales promelas, and ten chemicals were also tested with the salt-water grass shrimp, Palaemonetes pugio.

  2. Guidelines of Italian CCTN for classification of some effects of chemical substances

    Energy Technology Data Exchange (ETDEWEB)

    Mucci, N. [ISPESL, Monteporzio Catone, Rome (Italy). Dip. di Medicina del Lavoro; Camoni, I. [Ist. Superiore di Sanita`, Rome (Italy). Lab. di Tossicologia Applicata

    1996-03-01

    Definitions of the categories and the criteria for the classification of chemical substances on the basis of their potential carcinogenic, mutagenic and toxic-reproductive effects, elaborated by the Italian National Advisory Toxicological Committee (CCTN) in 1994. Besides all the allocations effected by the CCTN in the period 1977-1995 are reported, updated according to these criteria.

  3. Low corrosive chemical decontamination method using pH control. 2. Decomposition of reducing agent by using catalyst with hydrogen peroxide

    International Nuclear Information System (INIS)

    In the development of a new chemical decontamination method which provides a high decontamination effect, less corrosion of base metal, and less radioactive waste generation, we developed a decomposition method for oxalic acid coexisting with hydrazine to decrease the amount of radioactive waste. Using a catalyst of 0.5wt% Ru supported by activated carbon grains, we decomposed oxalic acid and hydrazine, simultaneously and efficiently, with a stoichiometric concentration of H2O2. The decomposition ratios were decreased by the deposition of oxides. But even if the simulated reducing agent solution with high concentrations of coexisting Fe and K ions, which negatively effect decomposition ratio, was decomposed, the decomposition ratios of oxalic acid and hydrazine were kept high during decomposition of the amount of reducing agent used in actual chemical decontamination. Additionally, we examined the deposition ratios of metal ions on the catalyst as metal oxides. These results indicated about 2% of the radioactive species which were removed by the chemical decontamination were deposited on the catalyst column. 59Fe and 51Cr were estimated to be about 90% of the total deposited amount of radioactive species and about 60% of the dose equivalent in the model calculation. But this problem should be easily dealt with by using shielding. (author)

  4. Assessment of chemical emissions in life cycle impact assessment - focus on low substance data availability and

    DEFF Research Database (Denmark)

    Larsen, Henrik Fred

    2004-01-01

    substance data on known emissions. To be able to characterize the potential toxic impacts on humans and the environment of chemical emissions, substance data on fate and effect are needed. The second goal of this thesis is to investigate how to deal with low substance data availability on especially effect...... ranking by negative logKow values is observed when logKow is a direct factor in the expression, and there is a significant influence of the way in which the BCF is estimated and included. The second part of the second goal of this thesis, which deals with low availability of substance effect data, is......, crustacean and fish, which in practice represent the trophic levels primary producers, primary consumers and secondary consumers, the use of a minimum of three acute EC50 values from each of these three throphic levels is recommended when estimating HC50EC50. Due to the comparative nature of LCA, the...

  5. 76 FR 38169 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2011-06-29

    ... FR 22402) (FRL-7312-2), and later amended by a final rule titled ``Revocation of TSCA Section 4... 12, 2006 (71 FR 18650) (FRL-7751-7). Section 4(d) of TSCA (15 U.S.C. 2603(d)) requires EPA to publish... AGENCY Toxic Substances Control Act Chemical Testing; Receipt of Test Data AGENCY:...

  6. Development of a technical scheme for the management of chemical dangerous substances in hospitable environments

    International Nuclear Information System (INIS)

    The chemical substances that are used in the hospitals, and their remainders, represent risks for the environment, the health and security of those who work in these establishments, and of the civil population. The deficiency of a norm that establishes the directives for the handling responsible for such products in the hospitals that our country has motivated the elaboration of a technical scheme that serves as it guides for the correct manipulation, storage and safe disposition of chemical substances in the twenty-nine hospitals of the Caja Costarricense del Seguro Social, establishing Procedures of Standard Operation for its management. To development of the guideline proposal it took a sample of hospitals that includes three levels of comple complexity: national, regional and peripheral. Applying a methodology of evaluation of risks two factors of risk of hospitable were determined, the zones and the population but affected by the existence of chemical substances, which allowed to identify some operative deficiencies in the product handling diverse. The qualitative analysis of the results lead to the elaboration of a technical scheme that includes an instrument for the identification of risks, guideline for the management responsible for hospitable chemical substances, a friendly tool computations like complementary source of intelligence and the proposal of a governing group in charge of the monitoring of the fulfillment of these lineament. (Author)

  7. Endocrine disrupting chemicals: harmful substances and how to test them

    Directory of Open Access Journals (Sweden)

    Olea-Serrano Nicolás

    2002-01-01

    Full Text Available This paper presents an analysis of the opinions of different groups from: scientists, international regulatory bodies, non-governmental organizations and industry; with an interest in the problem of identifying chemical substances with endocrine disrupting activity. There is also discussion of the consequences that exposure to endocrine disruptors may have for human health, considering concrete issues related to: the estimation of risk; the tests that must be used to detect endocrine disruption; the difficulties to establish an association between dose, time of exposure, individual susceptibility, and effect; and the attempts to create a census of endocrine disruptors. Finally, it is proposed that not all hormonal mimics should be included under the single generic denomination of endocrine disruptors.

  8. Self-assembly of humic acid: influence of pH and chemical composition

    Science.gov (United States)

    Chilom, G.; Nagy, Z.; Delp, S.; Huff, G.; Rice, J. A.

    2010-12-01

    Interest in enhancing the residence time of soil organic matter (SOM) through natural or engineered mechanisms as a possible means of sequestering organic carbon to mitigate the impacts of carbon-dioxide induced global warming effects has steadily increased over the last decade. Humic substances are major organic constituents of SOM and were recently shown that can self-organize or self-assemble into a composite material with different characteristics than those of the starting materials, and the organized state controls its mineralization by microorganisms. This study examines the role of pH and the relative concentration of humic-like amphiphilic (HA2) and lipid-like (L1) components in the self-assembly of the lipid-humic composite (L0). The L0, L1 and HA2 fractions were isolated using a combination of organic solvent and aqueous alkaline extractions from two humic acid samples at various pH values. HA2 and L1 isolated at low pH were mixed in various mass ratios in organic solvent in order to “reassemble” L0. The data show that the amount of L0 decreased with increasing the pH and reached a constant value from pH 6 to pH 11, and the proportion of L1 increased with the pH. Comparative measurements of the specific heat capacity as a function of temperature of the recombined L0 reveal differences when compared to the physical mixture of the HA2 and L1 depending on the ratio of the components. These differences are an indication that the recombined L0’s solid-state structure is more than just a mixture of components and is determined by specific interactions between its components.

  9. Sorption of 63Ni(II) to montmorillonite as a function of pH, ionic strength, foreign ions and humic substances

    International Nuclear Information System (INIS)

    Different kinds of clay minerals have been studied extensively in the removal of radionuclides from large volumes of aqueous solutions because of their high sorption capacity. Herein, the Na-montmorillonite was characterized by using XRD and FTIR in detail. The sorption of 63Ni(II) from aqueous solution to montmorillonite as a function of pH, ionic strength, foreign ions, humic substances and temperature was studied by batch technique. The sorption of 63Ni(II) on montmorillonite achieved equilibration quickly. The sorption of 63Ni(II) to montmorillonite was strongly dependent on pH, and dependent on ionic strength at low pH and independent of ionic strength at high pH values. The sorption of 63Ni(II) on montmorillonite was enhanced at low pH in the presence of humic acid (HA), while a negative effect of HA on 63Ni(II) sorption was found at high pH values. At low pH values, the sorption of 63Ni(II) was attributed to outer-sphere surface complexation or ion exchange, whereas the sorption was dominated by inner-sphere surface complexation at high pH values. The montmorillonite sample is a suitable material in the preconcentration of radionuclides from large volumes and the material can be used as backfill material in nuclear waste repository. (author)

  10. Discovery of Small Molecule Inhibitors of the PH Domain Leucine-Rich Repeat Protein Phosphatase (PHLPP) by Chemical and Virtual Screening

    OpenAIRE

    Sierecki, Emma; Sinko, William; McCammon, J. Andrew; Newton, Alexandra C.

    2010-01-01

    PH domain Leucine-rich repeat protein phosphatase (PHLPP) directly dephosphorylates and inactivates Akt and protein kinase C, poising it as a prime target for pharmacological intervention of two major survival pathways. Here we report on the discovery of small molecule inhibitors of the phosphatase activity of PHLPP, a member of the PP2C family of phosphatases for which there are no general pharmacological inhibitors. First, the Diversity Set of the NCI was screened for inhibition of the puri...

  11. Nonlocal Effects of Chemical Substances on the Brain Produced through Quantum Entanglement

    Directory of Open Access Journals (Sweden)

    Hu H.

    2006-07-01

    Full Text Available Photons are intrinsically quantum objects and natural long-distance carriers of information. Since brain functions involve information and many experiments have shown that quantum entanglement is physically real, we have contemplated from the perspective of our recent hypothesis on the possibility of entangling the quantum entities inside the brain with those in an external chemical substance and carried out experiments toward that end. Here we report that applying magnetic pulses to the brain when an anesthetic or pain medication was placed in between caused the brain to feel the effect of the said substance for several hours after the treatment as if the test subject had actually inhaled the same. The said effect is consistently reproducible. We further found that drinking water exposed to magnetic pulses, laser light or microwave when a chemical substance was placed in between also causes consistently reproducible brain effects in various degrees. Further, through additional experiments we have verified that the said brain effect is the consequence of quantum entanglement between quantum entities inside the brain and those of the chemical substance under study, induced by the photons of the magnetic pulses or applied lights. We suggest that the said quantum entities inside the brain are nuclear and/or electron spins and discuss the profound implications of these results.

  12. Risk Assessment of New Chemical Substances: System Realisation and Validation II

    NARCIS (Netherlands)

    Toet C; de Nijs ACM; Vermeire TG; van der Poel P; Tuinstra J

    1991-01-01

    In the project "Evaluation System new substances", methods are developed to systematically predict and assess the hazards for man and environment related to the production and use of new chemical substances. Part of the project is the realisation of a Risk Assessment System for New Chemic

  13. 76 FR 81441 - Proposed Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2011-12-28

    ... chemical substances rutile, tin zinc, calcium-doped (CAS No. 389623-01- 2) and rutile, tin zinc, sodium... orders. The two chemical substances are identified as rutile, tin zinc, calcium-doped (PMN P-06-36; CAS..., tin zinc, calcium-doped and (P- 06-37) Rutile, tin zinc, sodium-doped. CAS numbers: (P-06-36)...

  14. 77 FR 18752 - Benzidine-Based Chemical Substances; Di-n

    Science.gov (United States)

    2012-03-28

    ...'-[2-(2-hydroxy-1- naphthalenyl)diazenyl][1,1 '-biphenyl]-4-yl]diazenyl]- , lithium salt (1:3) 68214-82...)(2) SNUR for the benzidine-based chemical substances listed at Sec. 721.1660 (61 FR 52287, October 7...; Significant New Uses of Certain Chemical Substances; Final Rule (61 FR 52287, October 7, 1996). F. What...

  15. Transport of dangerous substances by road

    International Nuclear Information System (INIS)

    This book is a collection of the Finnish acts and regulations concerning transport of dangerous substances by road as of 31st March 1985. Included are: Act and Decree on the Transport of Dangerous Substances by Road (Nos 510/74 and 861/74), both as amended; Decree setting up a related Commission (No. 862/74), as amended; Act on the Contract for Carriage of Goods by Road (No. 345/79); Decree bringing into force the ADR (No. 289/79); and Decision of the Ministry of Communications on the Transport of Dangerous Substances by Road (No. 610/78) as amended by Decisions No. 344/79, 995/79, 218/82 and 935/83. (NEA)

  16. Mechanisms of humic substances degradation by fungi

    Science.gov (United States)

    Chen, Y.; Hadar, Y.; Grinhut, T.

    2012-04-01

    Humic substances (HS) are formed by secondary synthesis reactions (humification) during the decay process and transformation of biomolecules originating from plants and other dead organisms. In nature, HS are extremely resistant to biological degradation. Thus, these substances are major components in the C cycle and in the biosphere and therefore, the understanding of the process leading to their formation and transformation and degradation is vital. Fungi active in the decomposition process of HS include mainly ascomycetes and basidiomycetes that are common in the upper layer of forest and grassland soils. Many basidiomycetes belong to the white-rot fungi (WRF) and litter-decomposing fungi (LDF). These fungi are considered to be the most efficient lignin degraders due to their nonspecific oxidizing enzymes: manganese peroxidase (MnP), lignin peroxidase (LiP) and laccase. Although bacteria dominate compost and participate in the turnover of HS, their ability to degrade stable macromolecules such as lignin and HS is limited. The overall objectives of this research were to corroborate biodegradation processes of HS by WRF. The specific objectives were: (i) To isolate, identify and characterize HS degrading WRF from biosolids (BS) compost; (ii) To study the biodegradation process of three types of HS, which differ in their structure, by WRF isolated from BS compost; and (iii) To investigate the mechanisms of HA degradation by WRF using two main approaches: (a) Study the physical and chemical analyses of the organic compounds obtained from direct fungal degradation of HA as well as elucidation of the relevant enzymatic reactions; and (b) Study the enzymatic and biochemical mechanisms involved during HA degradation. In order to study the capability of fungi to degrade HS, seventy fungal strains were isolated from biosolids (BS) compost. Two of the most active fungal species were identified based on rDNA sequences and designated Trametes sp. M23 and Phanerochaetesp., Y6

  17. Families Affected by Parental Substance Use.

    Science.gov (United States)

    Smith, Vincent C; Wilson, Celeste R

    2016-08-01

    Children whose parents or caregivers use drugs or alcohol are at increased risk of short- and long-term sequelae ranging from medical problems to psychosocial and behavioral challenges. In the course of providing health care services to children, pediatricians are likely to encounter families affected by parental substance use and are in a unique position to intervene. Therefore, pediatricians need to know how to assess a child's risk in the context of a parent's substance use. The purposes of this clinical report are to review some of the short-term effects of maternal substance use during pregnancy and long-term implications of fetal exposure; describe typical medical, psychiatric, and behavioral symptoms of children and adolescents in families affected by substance use; and suggest proficiencies for pediatricians involved in the care of children and adolescents of families affected by substance use, including screening families, mandated reporting requirements, and directing families to community, regional, and state resources that can address needs and problems. PMID:27432847

  18. Four-Component Relativistic DFT Calculations of (13)C Chemical Shifts of Halogenated Natural Substances.

    Science.gov (United States)

    Casella, Girolamo; Bagno, Alessandro; Komorovsky, Stanislav; Repisky, Michal; Saielli, Giacomo

    2015-12-14

    We have calculated the (13)C NMR chemical shifts of a large ensemble of halogenated organic molecules (81 molecules for a total of 250 experimental (13)C NMR data at four different levels of theory), ranging from small rigid organic compounds, used to benchmark the performance of various levels of theory, to natural substances of marine origin with conformational degrees of freedom. Carbon atoms bonded to heavy halogen atoms, particularly bromine and iodine, are known to be rather challenging when it comes to the prediction of their chemical shifts by quantum methods, due to relativistic effects. In this paper, we have applied the state-of-the-art four-component relativistic density functional theory for the prediction of such NMR properties and compared the performance with two-component and nonrelativistic methods. Our results highlight the necessity to include relativistic corrections within a four-component description for the most accurate prediction of the NMR properties of halogenated organic substances. PMID:26541625

  19. Dynamic regulation of gastric surface pH by luminal pH

    OpenAIRE

    Chu, Shaoyou; Tanaka, Shin; Kaunitz, Jonathan D.; Montrose, Marshall H.

    1999-01-01

    In vivo confocal imaging of the mucosal surface of rat stomach was used to measure pH noninvasively under the mucus gel layer while simultaneously imaging mucus gel thickness and tissue architecture. When tissue was superfused at pH 3, the 25 μm adjacent to the epithelial surface was relatively alkaline (pH 4.1 ± 0.1), and surface alkalinity was enhanced by topical dimethyl prostaglandin E2 (pH 4.8 ± 0.2). Luminal pH was changed from pH 3 to pH 5 to mimic the fasted-to-fed transition in intra...

  20. Hemolytic anemia caused by chemicals and toxins

    Science.gov (United States)

    Anemia - hemolytic - caused by chemicals or toxins ... Possible substances that can cause hemolytic anemia include: Anti-malaria drugs (quinine compounds) Arsenic Dapsone Intravenous water infusion (not half-normal saline or normal saline) Metals (chromium/chromates, ...

  1. Quantitative Exposure Assessment of Various Chemical Substances in a Wafer Fabrication Industry Facility

    OpenAIRE

    Park, Hyunhee; Jang, Jae-Kil; Shin, Jung-Ah

    2011-01-01

    Objectives This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. Methods The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologi...

  2. Use of reserve substances by irradiated tubers

    International Nuclear Information System (INIS)

    The response of tubers of potato (Solanum tuberosun L.) and sweet potato (Ipomoea batatas L.) to gamma radiation from 60 Co were investigated. The use of reserve substances by the tubers increased when the irradiation dose raise up to the level of GR10-20 and then decreased down to the values lower than the control non-irradiated tubers

  3. Study the Migration Process of Chemical Substances through the Packaging/Food Interface during Microwave Treatment

    Directory of Open Access Journals (Sweden)

    Fang Duan

    2013-01-01

    Full Text Available The diffusion of chemical substances from packaging into food endangers people’s health. The migration amount of the chemical substances increases with the time and temperature, but the diffusion process for different kinds of packaging materials differs much. Most recently, the research community showed a renewed interest on the diffusion process of chemical substances through packaging/food interface during microwave treatment. In this study, the diffusion coefficient model is suggested and then the migration process is studied based on Fick’s diffusion law. The results are finally compared with the experimental data, showing good agreement.

  4. Changes in Some Chemical Characteristics of Compost Treated with Energetic Substances and Microbial Inoculants

    International Nuclear Information System (INIS)

    The main point of this study is the production of organic compost as an alternative source of nutrient and in the same time to reduce the environmental hazards caused by excessive application of chemical fertilizers. In this respect, the farm wastes (plant residues plus animal manure) were collected and treated with different energetic substances and microbial inoculants, in different ratios and combinations, to produce different compost forms. The composting process was carried out in cement tanks constructed in the field and designed with bottom outlet for collecting the compost tea (filtrate) to be used as a source of organic nutrients. Different characteristics of composted materials were determined to evaluate the quality and maturity of produced combinations. Samples of composted materials were collected for laboratory analyses with intervals begin from 24 hrs (0 time) up to 60 days. The given data revealed that ph values of composted materials tended to increase with time up to 60 days of incubation. This holds true with different composting treatments. In the same time, ph values were fluctuated according to composting treatments. Electrical conductivity (EC) values tended to increase up to 30 days and the highest values was recorded with T6 and the lowest one was recorded with T4. Both the treatments and incubation period have significant effects on nitrogen content of the composted materials. Also, T6 was the best treatment, which enriched the composted materials. The C/N ratio was decreased during the composting process. The initial ratio of C/N, which ranged between 22 and 72, substantially decreased in all windrows depending on its chemical composition. The originated organic matter was more able to degrade with time progress up to 60 days of incubation. In the same time, the addition of T6 had encouraged this process of degradation (mineralization of organic N). It seems that phosphorus percent in compost was frequently affected by additives. The

  5. Dangerous chemical substances – Tools supporting occupational risk assessment

    Directory of Open Access Journals (Sweden)

    Elżbieta Dobrzyńska

    2014-10-01

    Full Text Available The assessment of risk associated with exposure to chemicals in the work environment is a task that still poses a lot of difficulties for the employers. At the same time the probability of adverse health effects faced by an employee as a result of such risks, and the related employer’s material losses should motivate employers to seek effective solutions aimed at assessing the risks and controling them to an acceptable level by the application of appropriate preventive measures. The paper presents examples of tools to assist the employer in the risk assessment associated with the presence of chemical agents in the workplace. Examples of guides, manuals, checklists and various interactive tools, developed in Poland and other European Union (EU countries, as well as in countries outside the EU and international organizations are described. These tools have been developed to meet the current requirements of the law and allow a rough estimation of chemical risk and based on these estimates take further steps to improve working conditions and safety. Med Pr 2014;65(5:683–692

  6. Radium-226 determination in different substances without preliminary chemical isolation

    International Nuclear Information System (INIS)

    A method of radium-226 determination, based on the measurement of radon-222 quantity, extracted from the substance analyzed, is developed. Determination limit of radium, equal to 6.6x10-15 mass.%, is achieved at the expense of application of low-background proportional counter and special vacuum installation to fill the detector with working gas mixture

  7. Extraction of groundwater humic substances and characterization by synthetic resin

    International Nuclear Information System (INIS)

    Groundwater was sampled in depth of about 50m for extraction of humic substances in the groundwater. The extraction and concentration of the humic substances were performed with synthetic adsorption resins. The extracted humic substances and reference humic substances were made a comparison in chemical property. Aquatic humic substances from Nordic Lake and non-aquatic Aldrich Co. humic acids were selected for the reference material. The unprocessed groundwater and the humic substances extracted from the groundwater were compared in UV-vis spectra, fluorescence spectra and the concentration ratio of humic acid and fulvic acid which were important in order to know characteristics of humic substances. Humic substances extracted from the groundwater were compared with Nordic humic substances in molecular weight distribution, IR spectra and NMR spectra from a viewpoint of complexation with radionuclides. This resulted that the extracted humic substances showed similar characteristics to humic substances in the groundwater, and that the extracted humic substances had similar characteristics to Nordic humic substances in containing acidic functional group which contributed to complexation and in americium complexation where americium complexed uniformly, independent of the molecular weight distribution as important characteristics for evaluation of effects on migration of radionuclides. These obtained results imply that employed method was applicable to extract dissolved humic substances from groundwater in a non-destructive manner and the dissolved humic substances occurring in groundwater in Japan are similar to aquatic Nordic humic substances, which are available to purchase at IHSS (International Humic Substances Society), in complexation behavior with some kind of metal ions. (author)

  8. Effect of pH, Temperature, and Chemicals on the Endoglucanases and β-Glucosidases from the Thermophilic Fungus Myceliophthora heterothallica F.2.1.4. Obtained by Solid-State and Submerged Cultivation.

    Science.gov (United States)

    Teixeira da Silva, Vanessa de Cássia; de Souza Coto, Amanda Lais; de Carvalho Souza, Rafael; Bertoldi Sanchez Neves, Marcello; Gomes, Eleni; Bonilla-Rodriguez, Gustavo Orlando

    2016-01-01

    This work reports endoglucanase and beta-glucosidase production by the thermophilic fungus Myceliophthora heterothallica in solid-state (SSC) and submerged (SmC) cultivation. Wheat bran and sugarcane bagasse were used for SSC and cardboard for SmC. Highest endoglucanase production in SSC occurred after 192 hours: 1,170.6 ± 0.8 U/g, and in SmC after 168 hours: 2,642 ± 561 U/g. The endoglucanases and beta-glucosidases produced by both cultivation systems showed slight differences concerning their optimal pH and temperature. The number of endoglucanases was also different: six isoforms in SSC and ten in SmC. Endoglucanase activity remained above 50% after incubation between pH 3.0 and 9.0 for 24 h for both cultivation systems. The effect of several chemicals displayed variation between SSC and SmC isoenzymes. Manganese activated the enzymes from SmC but inhibited those from SSC. For β-glucosidases, maximum production on SmC was 244 ± 48 U/g after 168 hours using cardboard as carbon source. In SSC maximum production reached 10.9 ± 0.3 U/g after 240 h with 1 : 1 wheat bran and sugarcane bagasse. Manganese exerted a significant activation on SSC β-glucosidases, and glucose inhibited the enzymes from both cultivation systems. FeCl3 exerted the strongest inhibition for endoglucanases and β-glucosidases. PMID:27242927

  9. Effect of pH, Temperature, and Chemicals on the Endoglucanases and β-Glucosidases from the Thermophilic Fungus Myceliophthora heterothallica F.2.1.4. Obtained by Solid-State and Submerged Cultivation

    Directory of Open Access Journals (Sweden)

    Vanessa de Cássia Teixeira da Silva

    2016-01-01

    Full Text Available This work reports endoglucanase and beta-glucosidase production by the thermophilic fungus Myceliophthora heterothallica in solid-state (SSC and submerged (SmC cultivation. Wheat bran and sugarcane bagasse were used for SSC and cardboard for SmC. Highest endoglucanase production in SSC occurred after 192 hours: 1,170.6 ± 0.8 U/g, and in SmC after 168 hours: 2,642 ± 561 U/g. The endoglucanases and beta-glucosidases produced by both cultivation systems showed slight differences concerning their optimal pH and temperature. The number of endoglucanases was also different: six isoforms in SSC and ten in SmC. Endoglucanase activity remained above 50% after incubation between pH 3.0 and 9.0 for 24 h for both cultivation systems. The effect of several chemicals displayed variation between SSC and SmC isoenzymes. Manganese activated the enzymes from SmC but inhibited those from SSC. For β-glucosidases, maximum production on SmC was 244 ± 48 U/g after 168 hours using cardboard as carbon source. In SSC maximum production reached 10.9 ± 0.3 U/g after 240 h with 1 : 1 wheat bran and sugarcane bagasse. Manganese exerted a significant activation on SSC β-glucosidases, and glucose inhibited the enzymes from both cultivation systems. FeCl3 exerted the strongest inhibition for endoglucanases and β-glucosidases.

  10. Monitoring of ampicillin and its related substances by NMR.

    Science.gov (United States)

    Shamsipur, Mojtaba; Talebpour, Zahra; Bijanzadeh, Hamid Reza; Tabatabaei, Shamsoddin

    2002-11-01

    A 1H NMR procedure for the monitoring of ampicillin (Amp) and its main related substance in different media, has been developed. The characteristics peak of Amp, 6-aminopenicillanic acid (6-APA), phenylglycine (PhG), and penicilloic acid in the range of 0.5-0.9 and 3.0-4.5 ppm were used for their identification in drugs and serum samples. The quantitative works were performed based on the intensity of protons of the methyl group link to the beta-lactam cyclic of Amp and 6-APA and the aromatic protons of PhG relative to the protons of methylene group of maleic acid, as internal standard, at constant temperature. The resulting data are compared with those obtained with an HPLC method proposed by British Pharmacopoeia. Statistical studies show that, at a confidence limit of %95, there is no significant difference between the two methods. In comparison with the HPLC method, the proposed NMR method does not require any sample pretreatment, standard solution preparation, long analysis time and use of any carcinogenic solvent. The method was applied to the determination of Amp and its related substances in synthetic mixtures, drug powders and serum samples. PMID:12408898

  11. Possibilities of the misuse of chemical poisonous substance against civil population

    OpenAIRE

    SVOZILOVÁ, Jana

    2007-01-01

    There are numberless possibilities of how to misuse combat poisonous substances against a civilian population. In my bachelor work I dealt with a standard of a civilian population{\\crq}s protection after a terrorist attack with a use of one of the chosen nerve paralytic substances (NPS), and an ability of an integrated rescue system (IRS) how to solve this incurred situation. Nerve paralytic substance (NPS) belong to combat poisonous substances and they are characterized by its high toxicity....

  12. [Chemical constituents in higher polar substances from Desmodium caudatum].

    Science.gov (United States)

    Zhu, Dan; Wang, Di; Wang, Guang-Hui; Guo, Zhi-Jian; Zou, Xiu-Hong; Lin, Ting; Chen, Hai-Feng

    2014-08-01

    In this study the chemical constituents of the higher polar sustances from Desmodium caudatum were investigated.The compounds were isolated by using column chromatographies over silicagel, polyamide, ODS, Sephadex LH-20, and preparative HPLC. The structures of these compounds were identified on the basis of NMR and MS spectra. Thirteen compounds were obtained and their structures were identified as vanillin(1), loliolide(2), indole-3-carboxaldehyde(3), salicylic acid(4), swertisin(5), saccharumoside C(6), isosinensin (7), kaempferol 3-O-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside (8), isovitexin (9), vitexin (10), nothofagin(11), resveratroloside (12), and 2"-α-rhamnopyranosyl-7-O-methylvitexin (13). Except for compound 5, the remaining compounds were isolated from D. caudatum for the first time. Compounds 2, 3, 6-8, 11-13 were separated from the genus Desmodium for the first time. PMID:25509297

  13. Investigation of the genotoxicity of substances migrating from polycarbonate replacement baby bottles to identify chemicals of high concern.

    Science.gov (United States)

    Mertens, Birgit; Simon, Coraline; Van Bossuyt, Melissa; Onghena, Matthias; Vandermarken, Tara; Van Langenhove, Kersten; Demaegdt, Heidi; Van Hoeck, Els; Van Loco, Joris; Vandermeiren, Karin; Covaci, Adrian; Scippo, Marie-Louise; Elskens, Marc; Verschaeve, Luc

    2016-03-01

    Due to the worldwide concern that bisphenol A might act as an endocrine disruptor, alternative materials for polycarbonate (PC) have been introduced on the European market. However, PC-replacement products might also release substances of which the toxicological profile - including their genotoxic effects - has not yet been characterized. Because a thorough characterization of the genotoxic profile of all these substances is impossible in the short term, a strategy was developed in order to prioritize those substances for which additional data are urgently needed. The strategy consisted of a decision tree using hazard information related to genotoxicity. The relevant information was obtained from the database of the European Chemicals Agency (ECHA), in silico prediction tools (ToxTree and Derek Nexus(TM)) and the in vitro Vitotox(®) test for detecting DNA damage. By applying the decision tree, substances could be classified into different groups, each characterized by a different probability to induce genotoxic effects. Although none of the investigated substances could be unequivocally identified as genotoxic, the presence of genotoxic effects could neither be excluded for any of them. Consequently, all substances require more data to investigate the genotoxic potential. However, the type and the urge for these data differs among the substances. PMID:26802677

  14. Data banks of chemical substances and their toxicity

    International Nuclear Information System (INIS)

    Rapid proliferation in the development of new chemical compounds, coupled with the discovery and/or identification of those already in existence, has led to a significant need to investigate their physicochemical and biological properties, to document the knowledge gained, and to communicate that knowledge in as convenient a manner as possible. This paper presents and briefly discusses several prominent chemical databases

  15. Data banks of chemical substances and their toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Craig, D.K.

    1992-12-31

    Rapid proliferation in the development of new chemical compounds, coupled with the discovery and/or identification of those already in existence, has led to a significant need to investigate their physicochemical and biological properties, to document the knowledge gained, and to communicate that knowledge in as convenient a manner as possible. This paper presents and briefly discusses several prominent chemical databases.

  16. Data banks of chemical substances and their toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Craig, D.K.

    1992-01-01

    Rapid proliferation in the development of new chemical compounds, coupled with the discovery and/or identification of those already in existence, has led to a significant need to investigate their physicochemical and biological properties, to document the knowledge gained, and to communicate that knowledge in as convenient a manner as possible. This paper presents and briefly discusses several prominent chemical databases.

  17. Evidence of the chemical reaction of (18)O-labelled nitrite with CO2 in aqueous buffer of neutral pH and the formation of (18)OCO by isotope ratio mass spectrometry.

    Science.gov (United States)

    Tsikas, Dimitrios; Böhmer, Anke; Gros, Gerolf; Endeward, Volker

    2016-05-01

    Inorganic nitrite (NO2(-), ON-O(-) ←→ (-)O-NO) is the autoxidation product of nitric oxide (NO). Nitrite can also be formed from inorganic nitrate (ONO2(-)), the major oxidation product of NO in erythrocytes, by the catalytic action of bacterial nitrate reductase in gut and oral microflora. Nitrite can be reduced to NO by certain cellular proteins and enzymes, as well as in the gastric juice under acidic conditions. Hemoglobin, xanthine oxidoreductase and carbonic anhydrase (CA) have been reported to convert nitrite to NO. Renal CA isoforms are involved in the reabsorption of nitrite and may, therefore, play an important role in NO homeostasis. Yet, the mechanisms underlying the action of CA on nitrite are incompletely understood. The nitrate/nitrite system is regarded as a reservoir of NO. We have recently shown that nitrite reacts chemically with carbon dioxide (CO2), the regular substrate of CA. The present communication reports a stable isotope ratio mass spectrometry (IRMS) study on the reaction of NO2(-) and CO2 performed in 50 mM HEPES buffer of pH 7.4 at 37 °C. By using (18)O-labelled nitrite ((18)ON-O(-)/(-18)O-NO) and CO2 we observed formation of (18)O-labelled CO2. This finding is an unequivocal evidence of the chemical reaction of (18)ON-O(-)/(-18)O-NO with CO2. The reaction is rapid and involves nucleophilic attack of the negatively charged nitrite via one of its oxygen atoms on the partially positively charged CO2 molecule to form the putative intermediate (18)ON-O-CO2(-)/(-)O2C-(18)O-NO. The by far largest fraction of this intermediate decomposes back to (18)ON-O(-)/(-18)O-NO and CO2. A very small fraction of the intermediate, however, rearranges and finally decomposes to form (18)OCO and nitrite. This reaction is slower in the presence of an isolated erythrocytic CA isoform II. In summary, NO2(-), CO2 and CA are ubiquitous. The chemical reaction of NO2(-) with CO2 and its modulation by CA isoforms may play important roles in the transport of

  18. 75 FR 63827 - Integrated Risk Information System (IRIS); Request for Chemical Substance Nominations for 2011...

    Science.gov (United States)

    2010-10-18

    ... AGENCY Integrated Risk Information System (IRIS); Request for Chemical Substance Nominations for 2011... quantitative and qualitative risk information on effects that may result from exposure to specific chemical... delivery/courier. Please follow the detailed instructions provided in the SUPPLEMENTARY INFORMATION...

  19. 78 FR 62443 - Perfluoroalkyl Sulfonates and Long-Chain Perfluoroalkyl Carboxylate Chemical Substances; Final...

    Science.gov (United States)

    2013-10-22

    ... Executive Order 12866 (58 FR 51735, October 4, 1993), the Office of Management and Budget (OMB) has... people and the environment will generally not be exposed to chemical substances in articles (see 49 FR... acknowledges that importers of articles may have varying levels of knowledge about the chemical content of...

  20. Characterization of a novel mutation in NS1 protein of influenza A virus induced by a chemical substance for the attenuation of pathogenicity.

    Directory of Open Access Journals (Sweden)

    Kohei Sasaki

    Full Text Available It is generally accepted that live attenuated influenza vaccine (LAIV has the potential for use as a vaccination against flu. In this study, we demonstrated the nature of an influenza A virus (IAV mutant induced by treating the IAV with a stable furan derivative, (1R,2R-1-(5'-methylfur-3'-ylpropane-1,2,3-triol (MFPT, which had been isolated from Streptomyces sp. strain FV60 with the objective of it being an LAIV candidate. The resulting MFPT-resistant (MFPTr IAVs possessed attenuated pathogenicity in vitro and in vivo when compared with that of the parent virus (H1N1 subtype, NWS strain. Sequencing analysis revealed that a novel mutation, C490U in ns gene (P164S in NS1, was detected in all MFPTr virus clones tested. Therefore, NS1 might be a main target of MFPT, and it was suggested that the P164S mutation contributed to the attenuated pathogenicity of the mutants. Although the phosphatidylinositol 3-kinase (PI3K/Akt signaling pathway is one of the targets of NS1, the MFPTr virus suppressed the phosphorylation of Akt when compared with the wild-type (WT virus. It was suggested that this might lead to the subsequent inhibition of the cleavage of PARP-1 and caspase-3, which is important for the progression of apoptosis. At the same time, nucleoprotein (NP was found to be retained in the nuclei in MFPTr virus-infected cells while nuclear export of NP was detected in WT virus-infected cells. In addition, the expression levels of interferon-β transcripts were significantly decreased in MFPTr virus-infected cells. From these results it can be shown that the mutation, NS1P164S, might be one of the key residues to control NS1 function concerning the induction of apoptosis. In conclusion, MFPT induced favorable mutation in the ns gene for the attenuation of IAV, and therefore might provide the novel methodology for preparing LAIVs.

  1. Monitoring natural organic matter in surface water by UV spectroscopy : effects of calcium, magnesium and pH value

    OpenAIRE

    Rodrigues, A. L.; Nogueira, R; Janknecht, P.; Brito, A. G.

    2006-01-01

    The aim of this study was to evaluate the effects of dissolved magnesium and calcium ions on the determination of humic substances in water by spectrophotometry at 254 nm. Quantifications were carried out for different pH values, both with and without filtration of the samples. The smallest effects were observed for unfiltered samples and neutral pH values.

  2. The uptake of polluting chemicals into the plant and its relationship to physical-chemical substance properties

    International Nuclear Information System (INIS)

    The accumulation behaviour of 14C-labelled organic pollutants under laboratory and field conditions was investigated in spring barley and garden cress and evaluated in the light of a number of previously selected substance properties. The studies in the laboratory were restricted to one week, while those in the field were carried out over the entire growing season. They had the purpose of determining the accumulation of certain pollutants in the test plants with reference to the residues detected for those substances in the soil. The laboratory studies were focused on benzene and five chlorated derivatives as well as a further few chemicals from other groups of substances. The substances investigated in the field were benzene and an additional three chlorated benzenes. The accumulation of organic pollutants in the above-ground parts and roots of barley can rather easily be forecasted on the basis of the compounds' structural properties like molecular weight, molecule volume and connectivity indices. This applies to the majority of cases, providing the mineralisation of the substances in the soil is only minor and no unduly large amounts of metabolites are formed, the physical-chemical properties of which deviate greatly from those of the mother substances. Any such forecasts for cress should preferably be made on the basis of distribution parameters of the individual compounds. It was found that the results from laboratory and field studies were in reasonable agreement, thus permitting the same conclusions to be drawn as to the biotransfer of the test substances from the soil and the probable links between these observations and physical-chemical substance properties. (orig./MG)

  3. PH Sensitive Polymers for Improving Reservoir Sweep and Conformance Control in Chemical Flooring

    Energy Technology Data Exchange (ETDEWEB)

    Mukul Sharma; Steven Bryant; Chun Huh

    2008-03-31

    There is an increasing opportunity to recover bypassed oil from depleted, mature oilfields in the US. The recovery factor in many reservoirs is low due to inefficient displacement of the oil by injected fluids (typically water). The use of chemical flooding methods to increase recovery efficiencies is severely constrained by the inability of the injected chemicals to contact the bypassed oil. Low sweep efficiencies are the primary cause of low oil recoveries observed in the field in chemical flooding operations even when lab studies indicate high oil recovery efficiency. Any technology that increases the ability of chemical flooding agents to better contact the remaining oil and reduce the amount of water produced in conjunction with the produced oil will have a significant impact on the cost of producing oil domestically in the US. This translates directly into additional economically recoverable reserves, which extends the economic lives of marginal and mature wells. The objective of this research project was to develop a low-cost, pH-triggered polymer for use in IOR processes to improve reservoir sweep efficiency and reservoir conformance in chemical flooding. Rheological measurements made on the polymer solution, clearly show that it has a low viscosity at low pH and exhibits a sudden increase in viscosity (by 2 orders of magnitude or more) at a pH of 3.5 to 4. This implies that the polymer would preferentially flow into zones containing water since the effective permeability to water is highest in these zones. As the pH of the zone increases due to the buffering capacity of the reservoir rock, the polymer solution undergoes a liquid to gel transition causing a sharp increase in the viscosity of the polymer solution in these zones. This allows operationally robust, in-depth conformance treatment of such water bearing zones and better mobility control. The rheological properties of HPAM solutions were measured. These include: steady-shear viscosity and

  4. The effect of pH, temperature and heating time on inulin chemical stability

    Directory of Open Access Journals (Sweden)

    Paweł Glibowski

    2011-06-01

    Full Text Available Background. Inulin is a storage carbohydrate found in many plants especially in chicory root, Jerusalem artichoke and dahlia tuber. It is a prebiotic with many functional properties. In earlier research concerning chemical stability of inulin, the effect of pH on rheological properties of inulin gels was mainly analysed. In these studies, the effect of time, temperature and pH on inulin chemical stability was not analysed profoundly especially considering the inulin concentrations unable to form gel structure. Thus, the aim of this work was to study the effect of the above mentioned factors on inulin chemical stability in water solution. Material and methods. 5% (w/w inulin solutions at pH 1-12 were heated at 20, 40, 60, 80 and 100°C for 5-60 min. After the neutralisation the content of reducing sugar was analysed according to Miller’s method (1959 with 3,5-dinitrosalicylic acid. Results. The conducted studies showed that inulin chemical stability at pH £ 4 decreased with an increase of heating time and temperature. In a neutral and basic environment inulin was chemically stable regardless of heating time and temperature. Conclusions. Inulin application in food systems may be limited in acidic products especially when heated above 60°C during the production process. However, in products at pH ≥ 5, the degradation of this fructan does not occur even at thermal processing.

  5. meeting) structurally related to a subgroup of substances within the group of ‘ Furfuryl and furan derivatives with and without additional side - chain substituents and heteroatoms from chemical group 14’ evaluated by JECFA in FGE.13Rev2 (2011)

    DEFF Research Database (Denmark)

    Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to consider evaluations of flavouring substances assessed since 2000 by the Joint FAO/WHO Expert Committee on Food Additives (the JECFA), and to decide whether further...... evaluation is necessary, as laid down in Commission Regulation (EC) No 1565/2000. The substances are evaluated through a stepwise approach that integrates information on structure-activity relationships, intake from current uses, toxicological threshold of concern, and available data on metabolism and...... toxicity. FGE.65 concerns a group of 33 sulfur-substituted furan derivatives evaluated by the JECFA at their 59th meeting. The Panel concluded in FGE.65 that the evaluation could not be finalised for four of the 33 substances [FL-no: 13.056, 13.160, 13.193 and 13.194] due to lack of toxicity data. In the...

  6. Substance Abuse by Youth and Young Adults in Rural America

    Science.gov (United States)

    Lambert, David; Gale, John A.; Hartley, David

    2008-01-01

    Purpose: Addressing substance abuse in rural America requires extending our understanding beyond urban-rural comparisons to how substance abuse varies across rural communities of different sizes. We address this gap by examining substance abuse prevalence across 4 geographic levels, focusing on youth (age 12-17 years) and young adults (age 18-25…

  7. Fixation and transport of uranium by humic substances (1962)

    International Nuclear Information System (INIS)

    One enter upon the study of the part taken by organic substances in ores that contain uranium in a disseminated form, without mineralization, being considered the reaction between uranium and humus. 'Humic acids' are extracted from the peat by ammonia. By the fact of their ability to cationic exchange, these are forming humates with metal cations; monovalent humates, normally soluble in water, can become insoluble after treatment of humic acids with methanal. The polyvalent humates are insoluble in water, especially humates of U (IV) and uranyl U (VI). Action of Li, Na, K, Mg, Ca uranyl carbonates solutions on the humic acids results in the formation of humates containing uranyl and the other cation. 100 g of humic acids give a fixation of no more than 38 g of uranium as uranyl. In contact with uraniferous weakly concentrated solutions, they fix 4 to 8 g according to pH, with a yield in the extraction greater than 95 per cent. The action of a sodium humate solution on a humate of uranyl give a solution containing a soluble sodium and uranyl humate. The solution is precipitated at various degrees by the polyvalent cations and insoluble humic substances. In all cases, the fixation of uranium with such prepared humic acids corresponds to a chemisorption of uranyl cations. (author)

  8. Extraction of scandium by organic substance melts

    International Nuclear Information System (INIS)

    Regularities of scandium extraction by the melts of octadecanicoic acid, n-carbonic acids of C17-C20 commerical fraction and mixtures of tributylphosphate (TBP) with paraffin at (70+-1) deg C have been studied. The optimum conditions for scandium extraction in the melt of organic substances are determined. A scheme of the extraction by the melts of higher carbonic acids at ninitial metal concentrations of 10-5 to 10-3 mol/l has been suggested. The scandium compound has been isolated in solid form, its composition having been determined. The main advantages of extraction by melts are as follows: a possibility to attain high distribution coefficients, distinct separation of phases after extraction, the absence of emulsions, elimination of employing inflammable and toxic solvents, a possibility of rapid X-ray fluorescence determinatinon of scandium directly in solid extract

  9. Analysis of determination modalities concerning the exposure and emission limits values of chemical and radioactive substances; Analyse des modalites de fixation des valeurs limites d'exposition et d'emission pour les substances chimiques et radioactives

    Energy Technology Data Exchange (ETDEWEB)

    Schieber, C.; Schneider, T

    2002-08-01

    This document presents the generic approach adopted by various organizations for the determination of the public exposure limits values to chemical and radioactive substances and for the determination of limits values of chemical products emissions by some installations. (A.L.B.)

  10. Regulation of antigen presentation by acidic pH

    OpenAIRE

    1990-01-01

    The effect of pH on functional association of peptide antigens with APC membranes was investigated by using aldehyde-fixed B cells and class II- restricted T cell hybridomas to assess antigen/MHC complex formation. The results indicated that the rate and extent of functional peptide binding was markedly increased at pH 5.0 as compared with pH 7.3. The pH dependence of binding was preserved after pretreatment of fixed APC with pH 5.0 buffer, suggesting that pH had a direct effect on the intera...

  11. Effects of radiation and chemical substances on cells and organism

    International Nuclear Information System (INIS)

    The book treats the radiation chemistry part of biophysics and applied biophysics in the sphere of ionizing radiation. Discussed are the concepts of radiation units and radioactivity units and the relative biological efficiency. The effects of ionizing and UV radiations are analyzed at the level of macromolecular changes. Chapters dealing with genetic radiation effects discuss the effects at the cellular level with respect to cell proliferation. All these problems are used to illustrate the effect on the organism as a whole. The chapters on applied biophysics deal with the indications of radiation and chemical damage, sensitivity of cells and the organism, and the study and influencing of growth at the cellular level. The concluding chapter is devoted to the environmental impact of radiation. (J.P.)

  12. 78 FR 69414 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2013-11-19

    ... October 21, 2011 (76 FR 65385) (FRL-8885-5) (docket ID number EPA-HQ-OPPT-2009-0112). The table in this... AGENCY Toxic Substances Control Act Chemical Testing; Receipt of Test Data AGENCY: Environmental Protection Agency (EPA). ACTION: Notice. SUMMARY: This notice announces EPA's receipt of test data on...

  13. 76 FR 38170 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2011-06-29

    ... issue of March 16, 2006 (71 FR 13708) (FRL-7335-2). Section 4(d) of TSCA (15 U.S.C. 2603(d)) requires... AGENCY Toxic Substances Control Act Chemical Testing; Receipt of Test Data AGENCY: Environmental Protection Agency (EPA). ACTION: Notice. SUMMARY: This notice announces EPA's receipt of test data on...

  14. 78 FR 27048 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2013-05-09

    ... average), tube ends (open, capped, circular, other), tube width/diameter (measure inner and outer diameters or range), tube length (range) including a description of any deformities found in the tubes... significant new use rules (SNURs) under the Toxic Substances Control Act (TSCA) for 15 chemical...

  15. Influence of soil pH on the sorption of ionizable chemicals

    DEFF Research Database (Denmark)

    Franco, Antonio; Fu, Wenjing; Trapp, Stefan

    2009-01-01

    The soil-water distribution coefficient of ionizable chemicals (K-d) depends on the soil acidity, mainly because the pH governs speciation. Using pH-specific K-d values normalized to organic carbon (K-OC) from the literature, a method was developed to estimate the K-OC of monovalent organic acids...... and bases. The regression considers pH-dependent speciation and species-specific partition coefficients, calculated from the dissociation constant (pK(a)) and the octanol-water partition coefficient of the neutral molecule (log P-n). Probably because of the lower pH near the organic colloid-water...... impact of pH on the total sorption is contrasting. In fact, the shortcomings of the model assumptions affect the predictive power for acids and for bases differently. We evaluated accuracy and limitations of the regressions for their use in the environmental fate assessment of ionizable chemicals....

  16. The testing of materials within the purview of the laws concerning the control of chemical substances

    International Nuclear Information System (INIS)

    The main approach adopted for this book is the question of whether and to what extent the commercially available chemical products (ranging from foodstuffs and drugs to pesticides and similar pollutants) have been assessed for environmental and health safety prior to release. The relevant existing laws concerning the testing and characterisation of substances are analysed and compared with a view to the major environmental principle, to prevent chemicals-induced hazards to health and the environment. The book reviews the following laws (and their implementing provisions): law on chemical substances, pesticides, fertilisers, drugs, detergents, leaded petrol, food and feedstuffs, explosives, and transport of hazardous materials. Environmentally significant laws reviewed include the waste management act, the atomic energy act (non-recycable wastes, plutonium, tritium), the water management act, and the act for protection against harmful effects on the environment. (orig./HP)

  17. Hemispheric pollution behavior studies of chemical and radiation substances

    International Nuclear Information System (INIS)

    Researchers at an air monitoring station in Quillayute, WA, measuring aerosol levels in the upper atmosphere, have determined from data collected from 1975 to 1977 that ozone concentrations peak in the spring and fall. The high ozone level in the spring probably results from ocean-trajectory air being brought in by strong off-shore flows; high levels in September and October may result from upper air being pushed down by upper-level high pressure areas and from polluted, stagnant air from the Puget Sound industrial area pushed westward by shifting flows

  18. Study of humic substances by fluorescence spectroscopy

    Directory of Open Access Journals (Sweden)

    Sona Konecna

    2010-12-01

    Full Text Available The purpose of this study is to determine main fluorophores of soil humic substances using 2D and 3D synchronous fluorescencespectroscopy (SFS. The measured synchronous spectra werecompared with standards IHSS. Differences between humic andfulvic acids as well as our and IHSS samples are discussed.

  19. Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat [Faculty of Science and Technology, University Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor (Malaysia); Amin, Mohd. Cairul Iqbal Mohd [Faculty of Pharmacy, University Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia)

    2014-09-03

    The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier.

  20. Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

    Science.gov (United States)

    Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat; Amin, Mohd. Cairul Iqbal Mohd

    2014-09-01

    The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier.

  1. Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

    International Nuclear Information System (INIS)

    The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier

  2. The physico-chemical properties and biostimulative activities of humic substances regenerated from lignite.

    Science.gov (United States)

    David, Jan; Smejkalová, Daniela; Hudecová, Sárka; Zmeškal, Oldřich; von Wandruszka, Ray; Gregor, Tomáš; Kučerík, Jiří

    2014-01-01

    The positive effect of humic acids on the growth of plant roots is well known, however, the mechanisms and role of their physical structure in these processes have not been fully explained yet. In this work, South-Moravian lignite was oxidized by means of nitric acid and hydrogen peroxide to produce a set of regenerated humic acids. The elemental composition, solid state stability and solution characteristics were determined and correlated in vitro with their biological activity. A modified hydroponic method was applied to determine the effects of their potassium salts on Zea mays seedlings roots with respect to the plant weight, root length, root division, and starch and protein content. The relations between the determined parameters were evaluated through Principal Component Analysis and Pearson's correlation coefficients. The results indicated that the most important factor determining the biological activity of South-Moravian lignite potassium humates is related to the nature of self-assemblies, while the chemical composition had no direct connection with the root growth of Zea mays seedlings. It was demonstrated a controlled processing that provided humic substances with different chemical and physicochemical properties and variable biological activity. PMID:24790812

  3. Indoor Air in Beauty Salons and Occupational Health Exposure of Cosmetologists to Chemical Substances

    Directory of Open Access Journals (Sweden)

    Nikos Evlogias

    2010-01-01

    Full Text Available The indoor environment in four beauty salons located in Athens (Greece was examined in order to investigate the occupational health exposure of cosmetologists to various chemical products typically used in their work. Chemical substances chosen for investigation were volatile organic compounds (VOCs, formaldehyde, ozone and carbon dioxide. Total VOCs levels measured showed significant variation (100–1,450 μg m-3 depending on the products used and the number of treatments carried out, as well as ventilation. The main VOCs found in the salons were aromatics (toluene, xylene, esters and ketones (ethyl acetate, acetone, etc. which are used as solvents in various beauty products; terpenes (pinene, limonene, camphor, menthenol which have a particular odor and others like camphor which have specific properties. Ozone concentrations measured in all salons were quite low (0.1 and 13.3 μg m-3 and formaldehyde concentrations detected were lower than the detection limit of the method in all salons (<0.05 ppm. Carbon dioxide levels ranged between 402 and 1,268 ppm, depending on the number of people present in the salons during measurements and ventilation. Cosmetologists may be exposed to high concentrations of a mixture of volatile organic compounds although these levels could be decreased significantly by following certain practices such as good ventilation of the areas, closing the packages of the beauty products when not in use and finally selecting safer beauty products without strong odor.

  4. Identification of Substances by THz Spectroscopy and Multivariate Analysis

    OpenAIRE

    Pohl, Andreas / AP; Deßmann, Nils / ND; Dutzi, Katja / KD; Hübers, Heinz-Wilhelm / HWH

    2014-01-01

    The identification of different substances based on terahertz transmittance spectra and multivariate analysis (MVA) is demonstrated. Transmittance spectra are obtained by the use of a Fourier transform infrared spectrometer (FTIR). By means of principal component analysis (PCA) and partial least squares regression (PLS) the spectral data were analyzed in order to discriminate and to identify the substances from each other.

  5. Influence of soil pH on the sorption of ionizable chemicals

    DEFF Research Database (Denmark)

    Franco, Antonio; Fu, Wenjing; Trapp, Stefan

    2009-01-01

    The soil-water distribution coefficient of ionizable chemicals (K-d) depends on the soil acidity, mainly because the pH governs speciation. Using pH-specific K-d values normalized to organic carbon (K-OC) from the literature, a method was developed to estimate the K-OC of monovalent organic acids...... and bases. The regression considers pH-dependent speciation and species-specific partition coefficients, calculated from the dissociation constant (pK(a)) and the octanol-water partition coefficient of the neutral molecule (log P-n). Probably because of the lower pH near the organic colloid......-water interface, the optimal pH to model dissociation was lower than the bulk soil pH. The knowledge of the soil pH allows calculation of the fractions of neutral and ionic molecules in the system, thus improving the existing regression for acids. The same approach was not successful with bases, for which the...

  6. Study of structure and chemical composition of soil humic substances isolated from humic podzol

    Czech Academy of Sciences Publication Activity Database

    Enev, V.; Klučáková, M.; Novák, František

    Brno : Masarykova univerzita, 2014, s. 23-27. ISBN 978-80-210-6842-1. [Pracovní setkání fyzikálních chemiků a elektrochemiků /14./. Brno (CZ), 03.06.2014-04.06.2014] Grant ostatní: GA MŠk(CZ) LO1211 Institutional support: RVO:60077344 Keywords : structure * chemical composition * soil humic substances * humic podzol Subject RIV: DF - Soil Science

  7. Influence of airborne chemical substances on the behaviour of radionuclides in boreal forest ecosystems

    International Nuclear Information System (INIS)

    Atmospheric deposition of chemical substances may influence the behaviour of radionuclides in soil and their uptake in plants. This is a fact that has so far received limited attention in radioecological studies. This paper presents briefly two cases where differences in atmospheric deposition of heavy metals from a strong pollution source and marine aerosols, respectively, influence the turnover of radionuclides in natural boreal ecosystems. (au)

  8. Classification of chemical substances, reactions, and interactions: The effect of expertise

    Science.gov (United States)

    Stains, Marilyne Nicole Olivia

    2007-12-01

    This project explored the strategies that undergraduate and graduate chemistry students engaged in when solving classification tasks involving microscopic (particulate) representations of chemical substances and microscopic and symbolic representations of different chemical reactions. We were specifically interested in characterizing the basic features to which students pay attention while classifying, identifying the patterns of reasoning that they follow, and comparing the performance of students with different levels of preparation in the discipline. In general, our results suggest that advanced levels of expertise in chemical classification do not necessarily evolve in a linear and continuous way with academic training. Novice students had a tendency to reduce the cognitive demand of the task and rely on common-sense reasoning; they had difficulties differentiating concepts (conceptual undifferentiation) and based their classification decisions on only one variable (reduction). These ways of thinking lead them to consider extraneous features, pay more attention to explicit or surface features than implicit features and to overlook important and relevant features. However, unfamiliar levels of representations (microscopic level) seemed to trigger deeper and more meaningful thinking processes. On the other hand, expert students classified entities using a specific set of rules that they applied throughout the classification tasks. They considered a larger variety of implicit features and the unfamiliarity with the microscopic level of representation did not affect their reasoning processes. Consequently, novices created numerous small groups, few of them being chemically meaningful, while experts created few but large chemically meaningful groups. Novices also had difficulties correctly classifying entities in chemically meaningful groups. Finally, expert chemists in our study used classification schemes that are not necessarily traditionally taught in classroom

  9. Sorption and desorption of uranium(VI) on GMZ bentonite. Effect of pH, ionic strength, foreign ions and humic substances

    International Nuclear Information System (INIS)

    The sorption and desorption of uranium(VI) on GMZ bentonite was investigated as functions of contact time, pH, ionic strength, foreign ions, HSs and initial U(VI) using batch experiments. It is revealed that the sorption strongly depended on pH, cations (Li+, Na+ and K+) and anions (CO32-, SO42- and PO43-). HA benefits the sorption at pH <7.0, while inhibited the sorption at higher pH. Moreover, the hysteresis occurred in the sorption-desorption process in the presence/absence of humic substances. The results could provide data base for the safety assessment of the deep geological disposal repository of high radioactive waste. (author)

  10. Extraction of substances assisted by ultrasound (UAE)

    International Nuclear Information System (INIS)

    Different compounds present in vegetables with functional or technological properties, have gained great importance in food, pharmaceutical and cosmetic markets. Efficient methods, economical and environment friendly are sought for the extraction of these substances. A literature review has been performanced of recent publications on different extraction methods and their comparison to the ultrasound assisted extraction (UAE) to assess their effectiveness and industrial viability. The ultrasound assisted extraction (UAE) has been found to be more efficient than traditional mining methods, and cheaper and easier than non-traditional extraction methods such as microwave-assisted extraction, so it checks its industrial viability. (author)

  11. Inorganic fractions in extracellular polymeric substance extracted from activated sludge and biofilm samples by different methods.

    Science.gov (United States)

    Zhang, Leiyan; Geng, Jinju; Ding, Lili; Ren, Hongqiang

    2012-01-01

    This study highlighted the inorganic fractions in the extracellular polymeric substance (EPS) extract from two activated sludges and one biofilm. Nine EPS extraction methods (centrifugation, sonication, cation exchange resin (CER) + sonication, CER, heating, formaldehyde + heating, formaldehyde + NaOH, ethanol and EDTA) were used in the study. The EPS extracts had large inorganic fractions, which ranged from 28% to 94% of the EPS dry weight. The EPS inorganic fraction was dependent on the source of the sludge and wastewater, the kinds of bacteria and the extraction method. The EPS extracts obtained by heating and sonication had smaller inorganic fractions than those obtained by centrifugation. The compositions of the inorganic fraction of EPS extracts obtained with CER and sonication + CER showed similar trends. The chemical extraction methods could contaminate the inorganic composition of EPS extracts by impurities, carrying over of the extractant itself or by changing the pH of the solution. Ethanol was the most effective extractant for obtaining inorganic ions. PMID:22828296

  12. Soil pH Dynamics and Nitrogen Transformations Under Long-Term Chemical Fertilization in Four Typical Chinese Croplands

    Institute of Scientific and Technical Information of China (English)

    MENG Hong-qi; XU Ming-gang; L Jia-long; HE Xin-hua; LI Jian-wei; SHI Xiao-jun; PENG Chang; WANG Bo-ren; ZHANG Hui-min

    2013-01-01

    Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems. We analyzed the historical (1990-2005) observations on four agricultural long-term experiments in China (Changping, Chongqing, Gongzhuling and Qiyang) under four different fertilizations, i.e., no-fertilizer (control), sole chemical nitrogen fertilizer (FN), sole chemical phosphorous and potassium fertilizers (FPK) and chemical nitrogen, phosphorous and potassium fertilizers (FNPK). The significant decline in topsoil pH was caused not only by chemical N fertilization (0.29 and 0.89∆pH at Gongzhuling and Qiyang, respectively) but also by chemical PK fertilization (0.59∆pH at Gongzhuling). The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P (168-599%)>available K (16-189%)>available N (9-33%). The relative rate of soil pH decline was lower under long-term judicious chemical fertilization (-0.036-0.034 ∆pH yr-1) than that under long-term sole N or PK fertilization (0.016-0.086 ∆pH yr-1). Long-term judicious chemical fertilization with N, P and K elements decreases the nutritional limitation to normal crop growth, under which more N output was distributed in biomass removal rather than the loss via nitrate leaching. We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.

  13. Impact of temperature, pH, and salinity changes on the physico-chemical properties of model naphthenic acids.

    Science.gov (United States)

    Celsie, Alena; Parnis, J Mark; Mackay, Donald

    2016-03-01

    The effects of temperature, pH, and salinity change on naphthenic acids (NAs) present in oil-sands process wastewater were modeled for 55 representative NAs. COSMO-RS was used to estimate octanol-water (KOW) and octanol-air (KOA) partition ratios and Henry's law constants (H). Validation with experimental carboxylic acid data yielded log KOW and log H RMS errors of 0.45 and 0.55 respectively. Calculations of log KOW, (or log D, for pH-dependence), log KOA and log H (or log HD, for pH-dependence) were made for model NAs between -20 °C and 40 °C, pH between 0 and 14, and salinity between 0 and 3 g NaCl L(-1). Temperature increase by 60 °C resulted in 3-5 log unit increase in H and a similar magnitude decrease in KOA. pH increase above the NA pKa resulted in a dramatic decrease in both log D and log HD. Salinity increase over the 0-3 g NaCl L(-1) range resulted in a 0.3 log unit increase on average for KOW and H values. Log KOW values of the sodium salt and anion of the conjugate base were also estimated to examine their potential for contribution to the overall partitioning of NAs. Sodium salts and anions of naphthenic acids are predicted to have on average 4 log units and 6 log units lower log KOW values, respectively, with respect to the corresponding neutral NA. Partitioning properties are profoundly influenced by the by the relative prevailing pH and the substance's pKa at the relevant temperature. PMID:26706930

  14. Chemical speciation of polycyclic aromatic hydrocarbons in sediments: Partitioning and extraction of humic substances

    International Nuclear Information System (INIS)

    The primary objective of this study was to examine the chemical speciation of polycyclic aromatic hydrocarbons (PAHs) found in sediments endowed with different characteristics. To achieve this purpose and because the nature of the sediments influences the distribution of PAHs, we have analyzed four different types of sediments. To study the role of organic matter in the sequestration of PAHs, we fractionated humic substances into humic acids and humin-mineral fractions. After their separation and purification, the humic components were examined for their sorptive reactivity by extracting them with organic solvents; these extracts were subsequently subjected to GC/MS analysis. Our results show that PAHs are distributed between labile and sequestered fractions in sediments. A slower uptake of PAHs occurs when the sequestered fraction is formed, and this process can be prolonged and may be influenced by the characteristics if the sediment. Our study suggests that organic contaminants are available in muddy sediments for a longer period of time than in sandy sediments.

  15. Cadmium sorption in solution by a chitin: effect of pH; Sorption du cadmium en solution par une chitine: effet du pH

    Energy Technology Data Exchange (ETDEWEB)

    Benguella, B.; Benaissa, H. [Universtie de Tlemcen, Lab. de Materiaux Sorbants et Traitement des Eaux, Dept. de Chimie, Faculte des Sciences, Tlemcen (Algeria)

    2001-07-01

    The pH is an essential factor to take into consideration in the sorption mechanisms of metals: it acts both on the metal speciation in solution and on the chemical behaviour of the surface of the sorbing material, and thus indirectly on the sorption mechanism. The effect of the initial pH of the solution on the cadmium sorption by raw state chitin has been studied in static conditions. The approach used is the determination of the sorption kinetics and equilibria for different values of initial pH (pH < 7-7.5). An increase of the initial pH value of the solution leads to an increase of the cadmium sorption capacity by chitin at the equilibrium. The Langmuir model has revealed to be convenient for a mathematical description of the sorption isotherms obtained. (J.S.)

  16. Comparison of Rumen Fluid pH by Continuous Telemetry System and Bench pH Meter in Sheep with Different Ranges of Ruminal pH

    OpenAIRE

    2014-01-01

    We aimed to compare the measurements of sheep ruminal pH using a continuous telemetry system or a bench pH meter using sheep with different degrees of ruminal pH. Ruminal lactic acidosis was induced in nine adult crossbred Santa Ines sheep by the administration of 15 g of sucrose per kg/BW. Samples of rumen fluid were collected at the baseline, before the induction of acidosis (T 0) and at six, 12, 18, 24, 48, and 72 hours after the induction for pH measurement using a bench pH meter. During ...

  17. Analysis of atorvastatin and related substances by MEKC

    OpenAIRE

    Nigović, Biljana; Damić, Miranda; Kočevar Glavač, Nina; Injac, Rade; Štrukelj, Borut

    2015-01-01

    A new micellar electrokinetic capillary chromatographic (MEKC) method has beendeveloped for simultaneous quantitation of atorvastatin and its related substances. The separation was carried out in an extended light path capillaryat applied voltage of 30 kV using a background electrolyte consistingof 10 mM sodium tetraborate buffer pH 9.5, 50 mM sodium dodecyl sulphate and 20% (v/v) methanol. The addition of methanol to the running buffer resulted in a very effective choice to achieve resolutio...

  18. Modulation by Substance P in the Lamprey Spinal Cord

    OpenAIRE

    Thörn Pérez, Carolina

    2013-01-01

    Neuromodulation is a key element for animal adaptation to environmental circumstances. Neuromodulators can alter the output of a physiological system by acting on the motor circuit by transforming intrinsic firing properties and altering synaptic strength. Substance P belongs to the family of tachykinin, which are peptidergic neuromodulators. The main focus of this thesis has been to characterize the effects of substance P in neurons and networks in the lamprey spinal cord. ...

  19. Microscale pH regulation by splitting water

    OpenAIRE

    Cheng, Li-Jing; Chang, Hsueh-Chia

    2011-01-01

    We present a simple, flexible approach for pH regulation in micro-chambers by injecting controllable amounts of protons and hydroxide ions via field-enhanced dissociation of water molecules. Under a DC voltage bias, the polymeric bipolar membranes integrated in microfluidics devices generate and separate H+ and OH− ions without gas production or contaminant generation resulting from electron-transfer reactions. Robust local on-chip pH and pH gradients are sustained with no need of additional ...

  20. A microfluidic platform with pH imaging for chemical and hydrodynamic stimulation of intact oral biofilms.

    Science.gov (United States)

    Gashti, M Parvinzadeh; Asselin, J; Barbeau, J; Boudreau, D; Greener, J

    2016-04-12

    A microfluidic platform with a fluorescent nanoparticle-based sensor is demonstrated for real-time, ratiometric pH imaging of biofilms. Sensing is accomplished by a thin patterned layer of covalently bonded Ag@SiO2+FiTC nanoparticles on an embedded planar glass substrate. The system is designed to be sensitive, responsive and give sufficient spatial resolution to enable new micro-scale studies of the dynamic response of oral biofilms to well-controlled chemical and hydrodynamic stimulation. Performance under challenging operational conditions is demonstrated, which include long-duration exposure to sheer stresses, photoexcitation and pH sensor biofouling. After comprehensive validation, the device was used to monitor pH changes at the attachment surface of a biofilm of the oral bacteria, Streptococcus salivarius. By controlling flow and chemical concentration conditions in the microchannel, biochemical and mass transport contributions to the Stephan curve could be probed individually. This opens the way for the analysis of separate contributions to dental caries due to localized acidification directly at the biofilm tooth interface. PMID:26956837

  1. Psychoactive substance use by truck drivers: a systematic review

    OpenAIRE

    Girotto, Edmarlon; Mesas, Arthur Eumann; de Andrade, Selma Maffei; Birolim, Marcela Maria

    2013-01-01

    The aim of this study was to summarise the scientific evidence on the prevalence of psychoactive substance use and on the factors associated with their intake among truck drivers. A systematic review was performed in the databases PubMed, Scientific Electronic Library Online, Latin American and Caribbean Health Sciences, and Cochrane and 36 cross-sectional studies were identified with quantitative results about the use of psychoactive substances by truck drivers. Out of these, 28 were carried...

  2. Preferences for Treatment Setting by Substance Users in India

    OpenAIRE

    Anju Dhawan; Anita Chopra; Rajat Ray

    2016-01-01

    Background: Drug and alcohol use is a growing public health concern for India. Treatment services delivery for substance use disorders is available through three sectors viz. Government (GO) centres under Ministry of Health and FW, Non-Government (NGO) under Ministry of Social Justice and Empowerment and the private sector. Information on ttreatment utilisation and preferences of treatment settings by substance users are not available for India. Methods: A performa was filled up prospectively...

  3. Physico-chemical characterization of secondary organic aerosol derived from catechol and guaiacol as a model substance for atmospheric humic-like substances

    Directory of Open Access Journals (Sweden)

    J. Ofner

    2010-07-01

    Full Text Available Secondary organic aerosol was produced from the aromatic precursors catechol and guaiacol by reaction with ozone in the presence and absence of simulated sunlight and humidity and investigated for its properties as a proxy for humic-like substances (HULIS. Beside a small particle size, a relatively low molecular weight and typical optical features in the UV/VIS spectral range, HULIS contain a typical aromatic and/or olefinic chemical structure and highly oxidized functional groups within a high chemical diversity. Various methods were used to characterize the secondary organic aerosols obtained: Fourier transform infrared spectroscopy (FTIR demonstrated the formation of different carbonyl containing functional groups as well as structural and functional differences between aerosols formed at different environmental conditions. UV/VIS spectroscopy of filter samples showed that the particulate matter absorbs far into the visible range up to more than 500 nm. Ultrahigh resolved mass spectroscopy (ICR-FT/MS determined O/C-ratios between 0.3 and 1 and main molecular weights between 200 and 500 Da. Temperature-programmed-pyrolysis mass spectroscopy identified carboxylic acids and lactones as major functional groups. Particle sizing using CNC-DMPS demonstrated the formation of small particles during a secondary organic aerosol formation process. Particle imaging using field-emission-gun scanning electron microscopy (FEG-SEM showed spherical particles, forming clusters and chains. Hence, secondary organic aerosols from catechol and guaiacol are appropriate model substances for studies of the processing of aromatic secondary organic aerosols and atmospheric HULIS on the laboratory scale.

  4. Synthesis of iron-based chemical looping sorbents integrated with pH swing carbon mineral sequestration.

    Science.gov (United States)

    Kim, Hyung Ray; Lee, Dong Hyun; Fan, Liang-Shih; Park, Ah-Hyung Alissa

    2009-12-01

    The previously developed pH swing carbon mineral sequestration immobilizes the gaseous CO2 into a thermodynamically stable solid, MgCO3, using Mg-bearing minerals such as serpentine. This mineral carbonation technology is particularly promising since it generates value-added solid products: high surface area silica, iron oxide, and magnesium carbonate, while providing a safe and permanent storage option for CO2. By carefully controlling the pH of the system, these solids products can be produced with high purity. This study focuses on the synthesis of iron oxide particles as a chemical looping sorbent in order to achieve the integration between carbon capture and storage technologies. Since the solubility of Fe in aqueous phase is relatively low at neutral pH, the effect of the weak acid and chelating agents on the extraction of Fe from serpentine was investigated. The synthesized iron-based chemical looping sorbent was found to be as effective as commercially available iron oxide nanoparticles at converting syngas into high purity H2, while producing a sequestration-ready CO2 stream. PMID:19908801

  5. Chemical modification and pH dependence of kinetic parameters to identify functional groups in a glucosyltransferase from Strep. Mutans

    International Nuclear Information System (INIS)

    A glucosyltransferase, forming a predominantly al-6 linked glucan, was partially purified from the culture filtrate of S. mutans GS-5. The kinetic properties of the enzyme, assessed using the transfer of 14C glucose from sucrose into total glucan, were studied at pH values from pH 3.5 to 6.5. From the dependence of km on pH, a group with pKa = 5.5 must be protonated to maximize substrate binding. From plots of V/sub max/ vs pH two groups, with pKa's of 4.5 and 5.5 were indicated. The results suggest the involvement of either two carboxyl groups (one protonated, one unprotonated in the native enzyme) or a carboxyl group (unprotonated) and some other protonated group such as histidine, cysteine. Chemical modification studies showed that Diethylyrocarbonate (histidine specific) had no effect on enzyme activity while modification with p-phydroxy-mercuribenzoate or iodoacetic acid (sulfhydryl reactive) and carbodimide reagents (carboxyl specific) resulted in almost complete inactivation. Activity loss was dependent upon time of incubation and reagent concentration. The disaccharide lylose, (shown to be an inhibitor of the enzyme with similar affinity to sucrose) offers no protection against modification by the sulfhydryl reactive reagents

  6. Anti-biofilm potential of phenolic acids: the influence of environmental pH and intrinsic physico-chemical properties.

    Science.gov (United States)

    Silva, Sara; Costa, Eduardo M; Horta, Bruno; Calhau, Conceição; Morais, Rui M; Pintado, M Manuela

    2016-09-13

    Phenolic acids are a particular group of small phenolic compounds which have exhibited some anti-biofilm activity, although the link between their activity and their intrinsic pH is not clear. Therefore, the present work examined the anti-biofilm activity (inhibition of biomass and metabolic activity) of phenolic acids in relation to the environmental pH, as well as other physico-chemical properties. The results indicate that, while Escherichia coli was not inhibited by the phenolic acids, both methicillin resistant Staphylococcus aureus and methicillin resistant Staphylococcus epidermidis were susceptible to the action of all phenolic acids, with the pH playing a relevant role in the activity: a neutral pH favored MRSE inhibition, while acidic conditions favored MRSA inhibition. Some links between molecular polarity and size were associated only with their potential as metabolic inhibitors, with the overall interactions hinting at a membrane-based mechanism for MRSA and a cytoplasmic effect for MRSE. PMID:27434592

  7. Chemical Leukoderma Improved by Low-dose Steroid Pulse Therapy

    OpenAIRE

    Jung, Jae Yoon; Yeom, Kkot Bora; Eun, Hee Chul

    2010-01-01

    Chemical leukoderma occurs due to the toxic effect of a specific chemical preceding allergic contact dermatitis. The mechanism is either destruction or inhibition of melanocytes by the offending substance. Clinicohistopathologically, no absolute criteria can differentiate chemical leukoderma from vitiligo. However, chemical leukoderma can be diagnosed clinically by a history of repeated exposure to a known or suspected depigmenting agent at the primary site. There is no agreed treatment guide...

  8. Gallic Acid as a Complexing Agent for Copper Chemical Mechanical Polishing Slurries at Neutral pH

    Science.gov (United States)

    Kim, Yung Jun; Kang, Min Cheol; Kwon, Oh Joong; Kim, Jae Jeong

    2011-05-01

    Gallic acid was investigated as a new complexing agent for copper (Cu) chemical mechanical polishing slurries at neutral pH. Addition of 0.03 M gallic acid and 1.12 M H2O2 at pH 7 resulted in a Cu removal rate of 560.73±17.49 nm/min, and the ratio of the Cu removal rate to the Cu dissolution rate was 14.8. Addition of gallic acid improved the slurry performance compared to glycine addition. X-ray photoelectron spectroscopy analysis and contact angle measurements showed that addition of gallic acid enhanced the Cu polishing behavior by suppressing the formation of surface Cu oxide.

  9. pH sensing by intracellular Salmonella induces effector translocation.

    Science.gov (United States)

    Yu, Xiu-Jun; McGourty, Kieran; Liu, Mei; Unsworth, Kate E; Holden, David W

    2010-05-21

    Salmonella enterica is an important intracellular bacterial pathogen of humans and animals. It replicates within host-cell vacuoles by delivering virulence (effector) proteins through a vacuolar membrane pore made by the Salmonella pathogenicity island 2 (SPI-2) type III secretion system (T3SS). T3SS assembly follows vacuole acidification, but when bacteria are grown at low pH, effector secretion is negligible. We found that effector secretion was activated at low pH from mutant strains lacking a complex of SPI-2-encoded proteins SsaM, SpiC, and SsaL. Exposure of wild-type bacteria to pH 7.2 after growth at pH 5.0 caused dissociation and degradation of SsaM/SpiC/SsaL complexes and effector secretion. In infected cells, loss of the pH 7.2 signal through acidification of host-cell cytosol prevented complex degradation and effector translocation. Thus, intravacuolar Salmonella senses host cytosolic pH, resulting in the degradation of regulatory complex proteins and effector translocation. PMID:20395475

  10. The high pH chemical and radiation compatibility of various liner materials

    International Nuclear Information System (INIS)

    A flexible membrane liner has been proposed to line a concrete vault in which liquid low-level radioactive waste will be solidified. High-density polyethylene (HDPE) and polypropylene liners were tested at the Pacific Northwest Laboratory in an EPA method 9090 format to determine their chemical compatibility with the waste. Radiation effects were also investigated. The liners were immersed in a highly caustic (pH>14), primarily inorganic solution at 90 degrees C. The liners were subjected to radiation doses up to 38.9 Mrad, which was the expected dose the liner would receive over a 30-year life inside the vault. Recent changes have placed the liner outside the vault. The acceptance criteria for judging the compatibility of the liner with radiation should be different than those used for judging chemical compatibility. The radiation damage over the life of the liner can be simulated in a short-term test. Both HDPE and polypropylene liners were judged to be acceptable from a chemical and radiation standpoint when placed outside of the vault, while several other liners were not compatible. Radiation did not have a significant effect on chemical degradation rates

  11. 75 FR 35977 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2010-06-24

    ... Harmonized Test Guideline 850.1400) with rainbow trout; and a daphnid chronic toxicity test (OCSPP Harmonized... tests would help characterize the environmental effects of the PMN substances: A fish acute toxicity...-hour renewal intervals; a fish acute toxicity test mitigated by humic acid (OCSPP Harmonized...

  12. Substance Flow Analysis and Source Mapping of Chemical UV-filters

    International Nuclear Information System (INIS)

    Chemical ultraviolet (UV)-filters are used in sunscreens to protect the skin from harmful UV radiation which may otherwise cause sunburns and skin cancer. Commonly used chemical UV-filters are known to cause endocrine disrupting effects in both aquatic and terrestrial animals as well as in human skin cells. Here, source mapping and substance flow analysis were applied to find the sources of six UV-filters (oxybenzone, avobenzone, 4-methylbenzylidene camphor, octyl methoxycinnamate, octyl dimethyl PABA and homosalate) and to identify the most dominant flows of these substances in Denmark. Urban water, composed of wastewater and surface waters, was found to be the primary recipient of UV-filters, whereby wastewater received an estimated 8.5-65 tonnes and surface waters received 7.1-51 tonnes in 2005. In wastewater treatment plants, their sorption onto sludge is perceived to be an important process and presence in effluents can be expected due to a lack of biodegradability. In addition, the use of UV-filters is expected to continue to increase significantly. Not all filters (e.g., octyl dimethyl PABA and homosalate) are used in Denmark. For example, 4-MBC is mainly associated with self-tanning liquids and private import of sunscreens

  13. Substance Flow Analysis and Source Mapping of Chemical UV-filters

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, E., E-mail: eve@env.dtu.dk; Andersen, H. R.; Ledin, A. [Technical University of Denmark, Department of Environmental Engineering (Denmark)

    2008-12-15

    Chemical ultraviolet (UV)-filters are used in sunscreens to protect the skin from harmful UV radiation which may otherwise cause sunburns and skin cancer. Commonly used chemical UV-filters are known to cause endocrine disrupting effects in both aquatic and terrestrial animals as well as in human skin cells. Here, source mapping and substance flow analysis were applied to find the sources of six UV-filters (oxybenzone, avobenzone, 4-methylbenzylidene camphor, octyl methoxycinnamate, octyl dimethyl PABA and homosalate) and to identify the most dominant flows of these substances in Denmark. Urban water, composed of wastewater and surface waters, was found to be the primary recipient of UV-filters, whereby wastewater received an estimated 8.5-65 tonnes and surface waters received 7.1-51 tonnes in 2005. In wastewater treatment plants, their sorption onto sludge is perceived to be an important process and presence in effluents can be expected due to a lack of biodegradability. In addition, the use of UV-filters is expected to continue to increase significantly. Not all filters (e.g., octyl dimethyl PABA and homosalate) are used in Denmark. For example, 4-MBC is mainly associated with self-tanning liquids and private import of sunscreens.

  14. Chemical modification of triplex-forming oligonucleotide to promote pyrimidine motif triplex formation at physiological pH.

    Science.gov (United States)

    Torigoe, Hidetaka; Nakagawa, Osamu; Imanishi, Takeshi; Obika, Satoshi; Sasaki, Kiyomi

    2012-04-01

    Extreme instability of pyrimidine motif triplex DNA at physiological pH severely limits its use in wide variety of potential applications, such as artificial regulation of gene expression, mapping of genomic DNA, and gene-targeted mutagenesis in vivo. Stabilization of pyrimidine motif triplex at physiological pH is, therefore, crucial for improving its potential in various triplex-formation-based strategies in vivo. To this end, we investigated the effect of 3'-amino-2'-O,4'-C-methylene bridged nucleic acid modification of triplex-forming oligonucleotide (TFO), in which 2'-O and 4'-C of the sugar moiety were bridged with the methylene chain and 3'-O was replaced by 3'-NH, on pyrimidine motif triplex formation at physiological pH. The modification not only significantly increased the thermal stability of the triplex but also increased the binding constant of triplex formation about 15-fold. The increased magnitude of the binding constant was not significantly changed when the number and position of the modification in TFO changed. The consideration of the observed thermodynamic parameters suggested that the increased rigidity of the modified TFO in the free state resulting from the bridging of different positions of the sugar moiety with an alkyl chain and the increased hydration of the modified TFO in the free state caused by the introduction of polar nitrogen atoms may significantly increase the binding constant at physiological pH. The study on the TFO viability in human serum showed that the modification significantly increased the resistance of TFO against nuclease degradation. This study presents an effective approach for designing novel chemically modified TFOs with higher binding affinity of triplex formation at physiological pH and higher nuclease resistance under physiological condition, which may eventually lead to progress in various triplex-formation-based strategies in vivo. PMID:22245184

  15. 78 FR 41768 - Chemical Substances and Mixtures Used in Oil and Gas Exploration or Production; TSCA Section 21...

    Science.gov (United States)

    2013-07-11

    ... AGENCY 40 CFR Chapter I Chemical Substances and Mixtures Used in Oil and Gas Exploration or Production...(a) to require manufacturers and processors of oil and gas exploration and production (E&P) chemical... Oil and Gas Exploration or Production.'' August 4, 2011. 3. EPA, ORD. EPA's Study of...

  16. Inhibition of crystallization caused by Proteus mirabilis during the development of infectious urolithiasis by various phenolic substances.

    Science.gov (United States)

    Torzewska, Agnieszka; Rozalski, Antoni

    2014-01-01

    Infectious urolithiasis is a consequence of persistent urinary tract infections caused by urease producing bacteria e.g. Proteus mirabilis. These stones are composed of struvite and carbonate apatite. Their rapid growth and high recurrence indicate that so far appropriate methods of treatment have not been found. In the present study, the inhibitory effect of phenolic compounds was investigated in vitro against formation of struvite/apatite crystals. The impact of these substances with different chemical structures on crystallization caused by clinical isolates of P. mirabilis was tested spectrophotometrically using a microdilution method. Among the 11 tested compounds resveratrol, epigallocatechin gallate, peralgonidin, vanillic and coffee acids at the concentrations 250-1000 μg/ml inhibited P. mirabilis urease activity and crystallization. However, only vanillic acid had such an effect on all tested strains of P. mirabilis. Therefore, using an in vitro model, bacterial growth, crystallization, urease activity and pH were examined for 24h in synthetic urine with vanillic acid. Effect of vanillic acid was compared with that of other known struvite/apatite crystallization inhibitors (acetohydroxamic acid, pyrophosphate) and it was shown that vanillic acid strongly inhibited bacterial growth and the formation of crystals. It can be assumed that this compound, after further studies, can be used in the treatment or prophylaxis of infectious urolithiasis. PMID:24239192

  17. Towards Process-Ontology: A Critical Study of Substance-Ontological Premises:Ph.D. Thesis at the Department of Philosophy, University of Pittsburgh, USA

    OpenAIRE

    Seibt, Johanna

    1990-01-01

    The thesis proposes therapeutic revision of fundamental assumptions in contemporary ontological thought. I show that non of the prevalent theories of objects, by virtue of certain implicit substance-ontological assumptions provides a viable account of the numerical, qualitative, and trans-temporal identity of objects. I argue that in order to explain the identity of objects we must abandon these substance-ontological premises together with the idea that objects enjoy ontological primacy. Whil...

  18. Creation of the ecology standards for the releases of the radionuclides and some chemical substances into environment

    International Nuclear Information System (INIS)

    An approach to creation of standards for radionuclide and other hazardous substance releases and effluents taking into account complex effects of hazardous substances on ecosystems is discussed. The approach is based on approximated standardization method according to indeterminate quality criterion. Determination of the ecosystem normal state when creating the standards for releases and effluents, as well as standardization of radiation and chemical effects upon ecosystems are reduced to the unified complex. The classification of aquatic objects in respect to radiation state is suggested. The standardization of radioactive substance releases and effluents based on the three-level system of standards is considered. 19 refs

  19. Research on elucidation of mechanism revealing capability of decomposing and removing harmful chemical substances in microorganisms and its utilization

    International Nuclear Information System (INIS)

    Recently, artificial harmful chemical substances are released in environment, and cause contamination as those are not decomposed by microorganisms. This research aims at clarifying the environmental factors which affect the revelation of the functions of decomposing and removing harmful chemical substances of microorganisms, separating and refining the enzymes and proteins which take part in the decomposition and removal and elucidating their properties, and further analyzing the genes taking part in the decomposition and removal functions and making the mechanism of revelation clear, elucidating the techniques giving the decomposition and removal functions to native bacteria living in nature and the conditions of improving the decomposing function, and utilizing these technologies for cleaning environment. As for the separation of the bacteria which decompose aliphatic halogen compounds and their decomposing characteristics, the experimental method and the effects that ethane concentration and carbon source exerted to the decomposition and others are reported. The elucidation of the mechanism of accumulating cesium in bacteria was carried out, and it is described. (K.I.)

  20. Substance P and substance K receptor binding sites in the human gastrointestinal tract: localization by autoradiography

    Energy Technology Data Exchange (ETDEWEB)

    Gates, T.S.; Zimmerman, R.P.; Mantyh, C.R.; Vigna, S.R.; Maggio, J.E.; Welton, M.L.; Passaro, E.P. Jr.; Mantyh, P.W.

    1988-11-01

    Quantitative receptor autoradiography was used to localize and quantify the distribution of binding sites for /sup 125/I-radiolabeled substance P (SP), substance K (SK) and neuromedin K (NK) in the human GI tract using histologically normal tissue obtained from uninvolved margins of resections for carcinoma. The distribution of SP and SK binding sites is different for each gastrointestinal (GI) segment examined. Specific SP binding sites are expressed by arterioles and venules, myenteric plexus, external circular muscle, external longitudinal muscle, muscularis mucosa, epithelial cells of the mucosa, and the germinal centers of lymph nodules. SK binding sites are distributed in a pattern distinct from SP binding sites and are localized to the external circular muscle, external longitudinal muscle, and the muscularis mucosa. Binding sites for NK were not detected in any part of the human GI tract. These results demonstrate that: (1) surgical specimens from the human GI tract can be effectively processed for quantitative receptor autoradiography; (2) of the three mammalian tachykinins tested, SP and SK, but not NK binding sites are expressed in detectable levels in the human GI tract; (3) whereas SK receptor binding sites are expressed almost exclusively by smooth muscle, SP binding sites are expressed by smooth muscle cells, arterioles, venules, epithelial cells of the mucosa and cells associated with lymph nodules; and (4) both SP and SK binding sites expressed by smooth muscle are more stable than SP binding sites expressed by blood vessels, lymph nodules, and mucosal cells.

  1. A Chemical Risk Ranking and Scoring Method for the Selection of Harmful Substances to be Specially Controlled in Occupational Environments

    Directory of Open Access Journals (Sweden)

    Saemi Shin

    2014-11-01

    Full Text Available This study aimed to devise a method for prioritizing hazardous chemicals for further regulatory action. To accomplish this objective, we chose appropriate indicators and algorithms. Nine indicators from the Globally Harmonized System of Classification and Labeling of Chemicals were used to identify categories to which the authors assigned numerical scores. Exposure indicators included handling volume, distribution, and exposure level. To test the method devised by this study, sixty-two harmful substances controlled by the Occupational Safety and Health Act in Korea, including acrylamide, acrylonitrile, and styrene were ranked using this proposed method. The correlation coefficients between total score and each indicator ranged from 0.160 to 0.641, and those between total score and hazard indicators ranged from 0.603 to 0.641. The latter were higher than the correlation coefficients between total score and exposure indicators, which ranged from 0.160 to 0.421. Correlations between individual indicators were low (−0.240 to 0.376, except for those between handling volume and distribution (0.613, suggesting that each indicator was not strongly correlated. The low correlations between each indicator mean that the indicators and independent and were well chosen for prioritizing harmful chemicals. This method proposed by this study can improve the cost efficiency of chemical management as utilized in occupational regulatory systems.

  2. PhD by Publication: A Student's Perspective

    Directory of Open Access Journals (Sweden)

    Peter Kanowski

    2008-01-01

    Full Text Available This article presents the first author's experiences as an Australian doctoral student undertaking a PhD by publication in the arena of the social sciences. She published nine articles in refereed journals and a peer-reviewed book chapter during the course of her PhD. We situate this experience in the context of current discussion about doctoral publication practices, in order to inform both postgraduate students and academics in general. The article discusses recent thinking about PhD by publication and identifies the factors that students should consider prior to adopting this approach, in terms of university requirements, supervisors' attitudes, the research subject matter, intellectual property, capacity and working style, and issues of co-authorship. It then outlines our perceptions of the advantages and disadvantages of undertaking a PhD by publication. We suggest that, in general, the advantages outweigh the disadvantages. We conclude by reflecting on how the first author's experiences relate to current discussions about fostering publications by doctoral students.

  3. Antimycobacterial activity of chemically defined natural substances from the Caribbean flora in Guadeloupe.

    Science.gov (United States)

    Rastogi, N; Abaul, J; Goh, K S; Devallois, A; Philogène, E; Bourgeois, P

    1998-04-01

    Eight chemically defined, naturally occurring compounds were extracted from the tropical flora of the Caribbean island of Guadeloupe: pilocarpine, an alkaloid from Pilocarpus racemosus; heraclenol and isomeranzin, coumarins from Triphasia trifolia; lochnerin, an indole alkaloid from Rauwolfia biauriculata; ibogaine and voacangine, indole alkaloids from Tabernaemontana citrifolia; texalin, an oxazole from Amyris elemifera; and canellal, a sesquiterpene dialdehyde from Canella winterana. An essential oil fraction from Canella winterana was also tested. The antimycobacterial activity of these substances was tested against Mycobacterium tuberculosis, M. avium and M. kansasii using the Middlebrook 7H11 agar medium, the Bactec 460-TB radiometric methodology, and determination of bacterial viable counts. Three compounds, namely ibogaine, voacangine and texalin, showed antimycobacterial activity. Investigations on the structure-modification and structure-activity relationships of these compounds may help determine new targets for future drug development. PMID:9626931

  4. Intellectual substance of lyrics by Joseph Brodsky

    Directory of Open Access Journals (Sweden)

    Plekhanova I. I.

    2015-01-01

    Full Text Available The features of J. Brodsky’s lyricism, which are caused by intellectual dominant of his consciousness, are explored in the article. Intellect here is understood as “directed thinking” (C. G. Jung; in artistic version it is described as project-reflexive thinking. The article gives basic characteristics of the poet’s consciousness, which caused maximum closeness between biographic and poetic “Me”, striving for alienation from the world and self-discipline in spiritual development. The connection between attitude towards the world and its’ artistic realization is observed. Brodsky’s way of thinking is noted for its abstractness of goal, for its insight of integrity of existence and non-existence. But this way of thinking is realized as decoding of material signs of manifestation of holism.

  5. Stabilization of extracellular polymeric substances (Bacillus subtilis) by adsorption to and coprecipitation with Al forms

    OpenAIRE

    Mikutta, R.; Zang, U.; Chorover, J.; Haumaier, L.; Kalbitz, K.

    2011-01-01

    Extracellular polymeric substances (EPS) are continuously produced by bacteria during their growth and metabolism. In soils, EPS are bound to cell surfaces, associated with biofilms, or released into solution where they can react with other solutes and soil particle surfaces. If such reaction results in a decrease in EPS bioaccessibility, it may contribute to stabilization of microbial-derived organic carbon (OC) in soil. Here we examined: (i) the chemical fractionation of EPS produced by a c...

  6. Development of a new QSPR based tool to predict explosibility properties of chemical substances within the framework of REACH and GHS

    OpenAIRE

    Fayet, Guillaume; ROTUREAU, Patricia; Joubert, Laurent; Adamo, Carlo

    2010-01-01

    The new European régulation of Chemicals named REACH (for "Registration, Evaluation and Authorization of Chemicals") turned out in the practical registration phase in December 2008. It requires the new assessment of hazard properties for up to 140000 substances. In this context, the development of alternative prédictive methods for assessing hazardous properties of chemical substances is promoted in REACH and in the related new European classification System of substances CLP (Classification,...

  7. Fiber-Optic pH Sensor

    Science.gov (United States)

    Ganesh, A. Balaji; Radhakrishnan, T. K.

    The new enhancement in the determination of pH using optical fiber system is described here. This work uses the membrane made of cellulose acetate membrane for reagent immobilization and congo red (pKa 3.7) and neutral red (pKa 7.2) as pH indicators. An effective covalent chemical binding procedure is used to immobilize the indicatorsE The response time, reversibility, linear range, reproducibility, and long-term stability of fiber optic sensor with congo red as well as neutral red have been determined. The linear range measured for the sensor based on the congo red and neutral red is 4.2-6.3 and 4.1-9.0, respectively. The response time of sensor membrane is measured by varying the substance pH values between 11.0 and 2.0.

  8. A methodology for determining environmental threshold quantities for substances covered by CEPA's Environmental Emergency Regulation

    International Nuclear Information System (INIS)

    Sections 199 and 200 of the Canadian Environmental Protection Act (CEPA) 1999 oblige persons who own or manage specified toxic and hazardous substances to develop and implement environmental emergency plans. This paper discussed the methodology for determining how a chemical is assessed for recommending an environmental emergency plan. For Section 199, once substances are declared toxic, each chemical is assessed to determine whether it requires a plan or not. For Section 200, any chemical can be added under the E2 regulations, as long as it can be ascertained that the substance is toxic according to the following criteria: it has an immediate or long-term harmful effect on the environment or its biological diversity; it constitutes a danger to the environment on which human life depends; and/or it constitutes a danger in Canada to human life or health. An overview of the risk evaluation framework was provided, including details of the pre-assessment filter. Summaries of trigger criteria were presented, as well as environmental hazard ratings and details of persistence of organic chemicals in the environment and bioaccumulation. Aquatic toxicity and ingestion toxicity details were also provided. Human hazard ratings included carcinogenicity, inhalation toxicity, dermal toxicity, rabbit and rat toxicity and corrosion and skin irritation ratings. Issues concerning vapour cloud explosions were examined. A reactivity table was presented with hazard descriptions. European Union Threshold quantities were examined, as well as a list of comparisons of selected substances of CEPA with the European Union. It was concluded that the Environmental Emergency Branch (EEB) has created environmental thresholds by first examining how other countries have protected the environment. Substance thresholds for the United States have focused on protecting humans, while Europe has established threshold quantities that work for their countries. The EEB has selected classification tables

  9. The Matthew Effect in Environmental Science Publication: A Bibliometric Analysis of Chemical Substances in Journal Articles

    OpenAIRE

    Grandjean Philippe; Eriksen Mette L; Ellegaard Ole; Wallin Johan A

    2011-01-01

    Abstract Background While environmental research addresses scientific questions of possible societal relevance, it is unclear to what degree research focuses on environmental chemicals in need of documentation for risk assessment purposes. Methods In a bibliometric analysis, we used SciFinder to extract Chemical Abstract Service (CAS) numbers for chemicals addressed by publications in the 78 major environmental science journals during 2000-2009. The Web of Science was used to conduct title se...

  10. Morphosynthesis of alanine mesocrystals by pH control.

    Science.gov (United States)

    Ma, Yurong; Cölfen, Helmut; Antonietti, Markus

    2006-06-01

    Crystallization of DL-alanine is studied as a single polymorph model case to analyze the different modes of crystallization of polar organic molecules in absence of any structure directing additives. Depending on supersaturation, which is controlled either by temperature or by pH, and in the absence of additives, crystallization by mesoscale assembly of nanoparticles is found over a wide range of conditions, leading to so-called mesocrystals. This supplements the classical molecule-based crystallization mechanism, which is identified at lower supersaturations and at pH values away from the isoelectric point (IEP). The resulting alanine crystals are characterized by SEM, XRD, and single-crystal analysis. Time-resolved conductivity measurements and dynamic light scattering of the reaction solutions reveal information about precursor structures and reaction kinetics. A formation mechanism is proposed for the alanine mesocrystals. PMID:16771332

  11. Physico-chemical model of toxic substances in the Great Lakes

    International Nuclear Information System (INIS)

    A physico-chemical model of the fate of toxic substances in the Great Lakes is constructed from mass balance principles and incorporates principal mechanisms of particulate sorption-desorption, sediment-water and atmosphere-water interactions, and chemical and biochemical decay. Calibration of the toxic model is through comparison to plutonium-239 data collected in the 1970s using a 23 year time variable calculation and indicates that in general, the sediments are interactive with the water column in the Great Lakes through resuspension and or horizontal transport. Fifty percent response times of 239Pu following a cessation of load extend beyond 10 years with sediment resuspension. The calibration model was applied to polychlorinated biphenyl (PCB) using a high and low estimate of contemporary external load and with and without volatilization. Calibration of the model to data on benzo(a)pyrene confirms that on a lake-wide scale the principal external source in the atmosphere and for the larger lakes such as Michigan the response time of the lake to external loads is about 6-10 years while for Lake Erie response time is about 2 years. Application of the model to cadmium in the lakes, using a solids dependent partition coefficient indicates that the lakes do not reach equilibrium over a 100 year period. Calculated high concentrations of cadmium in interstitial water (e.g., 10 microgram/l) indicate the importance of measuring interstitial cadmium concentrations

  12. Effect of pH on biologic degradation of Microcystis aeruginosa by alga-lysing bacteria in sequencing batch biofilm reactors

    Institute of Scientific and Technical Information of China (English)

    Hongjing LI; Mengli HAO; Jingxian LIU; Chen CHEN1; Zhengqiu FAN; Xiangrong WANG

    2012-01-01

    In this paper, the effect of pH on biological degradation of Microcystis aeruginosa by alga-lysing bacteria in laboratory-scale sequencing batch biofilm reactors (SBBRs) was investigated. After 10 d filming with waste activated sludge, the biological film could be formed, and the bioreactors in which laid polyolefin resin filler were used to treat algal culture. By comparing the removal efficiency of chlorophyll a at different aerobic time, the optimum time was determined as 5 h. Under pH 6.5, 7.5, and 8.5 conditions, the removal rates of Microcystis aeruginosa were respectively 75.9%, 83.6%, and 78.3% (in term of chlorophyll a), and that of Chemical Oxygen Demand (CODMn) were 30.6%, 35.8%, and 33.5%. While the removal efficiencies of ammonia nitrogen (NH+ -N) were all 100%. It was observed that the sequence of the removal efficiencies of algae, NH+ -N and organic matter were pH 7.5 〉 pH 8.5 〉 pH 6.5. The results showed that the dominant alga-lysing bacteria in the SBBRs was strain HM-01, which was identified as Bacillus sp. by Polymerase Chain Reaction (PCR) amplification of the 16S rRNA gene, Basic Local Alignment Search Tool (BLAST) analysis, and compar- ison with sequences in the GenBank nucleotide database. The algicidal activated substance which HM-01 strain excreted could withstand high temperature and pressure, also had better hydrophily and stronger polarity.

  13. Effect of test concentration in the ready biodegradability test for chemical substances: Improvement of OECD test guideline 301C.

    Science.gov (United States)

    Nabeoka, Ryosuke; Taruki, Masanori; Kayashima, Takakazu; Yoshida, Tomohiko; Kameya, Takashi

    2016-01-01

    In Japan, understanding the environmental persistence of chemicals is very important for risk assessment, and ready biodegradability tests are mainly conducted according to the Organisation for Economic Co-operation and Development test guideline 301C. However, the highest test concentration specified in test guideline 301C, 100 mg/L, may cause microbial toxicity and incomplete biodegradation. The authors performed test guideline 301C tests at test concentrations of 30 mg/L for 13 substances that were readily biodegradable in ready biodegradability tests but not in test guideline 301C tests. Of the 5 substances with potential to cause microbial toxicity at 100 mg/L, the percentage of biodegradation of sodium dimethyldithiocarbamate, 4-chloro-3-cresol (CC), thymol (THY), and p-tert-butyl-α-methylbenzenepropionaldehyde measured by biochemical oxygen demand (BOD) increased in the test guideline 301C test at 30 mg/L, suggesting a reduction in toxicity effects. Furthermore, CC and THY met the criteria for ready biodegradability, which are more than 60% of biodegradation by BOD and a 10-d window. Of the 8 substances with a low potential for causing microbial toxicity at 100 mg/L, the percentage of biodegradation of only 2-(diethylamino)ethanol increased in the test guideline 301C test at 30 mg/L. Employing a lower test concentration in the standard test guideline 301C test will contribute to improvement of consistency between results of a test guideline 301C test and other ready biodegradability tests. PMID:26211908

  14. Concentration of 'forgotten' substances using the XAD concentration method. Suitability of the method for hydrophilic chemicals

    NARCIS (Netherlands)

    Collombon MT; LER

    2007-01-01

    Concentration of forgotten substances using the XAD concentration method In the nineties, RIVM developed a method to concentrate toxic substances on XAD (a synthetic resin). Using bioassays, the toxicity can be determined in the concentrate. 'Modern' toxic substances tend to be more polar then 'clas

  15. Adapting SimpleTreat for simulating behaviour of chemical substances during industrial sewage treatment.

    Science.gov (United States)

    Struijs, J; van de Meent, D; Schowanek, D; Buchholz, H; Patoux, R; Wolf, T; Austin, T; Tolls, J; van Leeuwen, K; Galay-Burgos, M

    2016-09-01

    The multimedia model SimpleTreat, evaluates the distribution and elimination of chemicals by municipal sewage treatment plants (STP). It is applied in the framework of REACH (Registration, Evaluation, Authorization and Restriction of Chemicals). This article describes an adaptation of this model for application to industrial sewage treatment plants (I-STP). The intended use of this re-parametrized model is focused on risk assessment during manufacture and subsequent uses of chemicals, also in the framework of REACH. The results of an inquiry on the operational characteristics of industrial sewage treatment installations were used to re-parameterize the model. It appeared that one property of industrial sewage, i.e. Biological Oxygen Demand (BOD) in combination with one parameter of the activated sludge process, the hydraulic retention time (HRT) is satisfactory to define treatment of industrial wastewater by means of the activated sludge process. The adapted model was compared to the original municipal version, SimpleTreat 4.0, by means of a sensitivity analysis. The consistency of the model output was assessed by computing the emission to water from an I-STP of a set of fictitious chemicals. This set of chemicals exhibit a range of physico-chemical and biodegradability properties occurring in industrial wastewater. Predicted removal rates of a chemical from raw sewage are higher in industrial than in municipal STPs. The latter have typically shorter hydraulic retention times with diminished opportunity for elimination of the chemical due to volatilization and biodegradation. PMID:27344605

  16. Adapting SimpleTreat for simulating behaviour of chemical substances during industrial sewage treatment

    NARCIS (Netherlands)

    Struijs, J.; van de Meent, D.; Schowanek, D.; Buchholz, H.; Patoux, R.; Wolf, T.; Austin, T.; Tolls, J.; van Leeuwen, K.; Galay-Burgos, M.

    2016-01-01

    The multimedia model SimpleTreat, evaluates the distribution and elimination of chemicals by municipal sewage treatment plants (STP). It is applied in the framework of REACH (Registration, Evaluation, Authorization and Restriction of Chemicals). This article describes an adaptation of this model for

  17. [A survey of utilization of and problems with the MSDS in chemical substances management at workplaces in Kanagawa Prefecture].

    Science.gov (United States)

    Koshi, Kimiko; Mouri, Tetuo; Sugimori, Hiroki; Numano, Takashi; Ashida, Toshifumi; Hiro, Hisanori; Miyake, Hitoshi; Fukushima, Michiko; Ishiwata, Kouichi

    2002-09-01

    Kanagawa Occupational Health Promotion Center conducted a survey on how the MSDS is utilized at workplaces with more than 50 employees handling chemical substances, and what measures are taken to help employees to thoroughly understand information in the Material Safety Data Sheet (MSDS). Questionnaires were sent out to 265 enterprises in Kanagawa prefecture, putting questions to industrial physicians and industrial hygiene supervisors. The objective of the survey was to find out how MSDS is adopted in the system to manage occupational health, what improvements the survey respondents want in MSDS and what expectations the respondents have of our center. 193 enterprises (72.8%) returned answers to the questionnaire. The major findings are as follows. (1) In many companies, information on hazardous/toxic materials is "controlled by a division using such materials", and roughly half of the companies have compiled a common list shared throughout the company. (2) For the most part suppliers submit to the MSDS. Larger companies have a higher rate of posting up or filing the MSDS at their workplaces. Only 25.8% of the companies "rewrite the MSDS so that workers can understand it." (3) Companies that carry out a hazard/toxicity assessment before introducing a new chemical substance account for 72.1%, which is higher than we expected. It indicates that even though the companies don't manage the MSDS adequately, they are highly concerned about hazard control of chemical substances. (4) The rate of answering that "the current MSDS is not easy to understand" is higher among large-sized enterprises and lower among enterprises with fewer than 300 employees. (5) Asked what improvement needs to be made on the MSDS, the industrial physicians and industrial hygiene supervisors gave same answers such as "Workers find the terminology difficult to understand." and "Levels of toxicity can't be clearly identified." (6) The respondents expect our center to provide information for the MSDS

  18. Nitrification at Low pH by Aggregated Chemolithotrophic Bacteria

    OpenAIRE

    De Boer, W.; Klein Gunnewiek, P.J.A.; Veenhuis, M; Bock, E; Laanbroek, H. J.

    1991-01-01

    A study was performed to gain insight into the mechanism of acid-tolerant, chemolithotrophic nitrification. Microorganisms that nitrified at pH 4 were enriched from two Dutch acid soils. Nitrate production in the enrichment cultures was indicated to be of a chemolithoautotrophic nature as it was (i) completely inhibited by acetylene at a concentration as low as 1-mu-mol/liter and (ii) strongly retarded under conditions of carbon dioxide limitation. Electron microscopy of the enrichment cultur...

  19. Risk of severe driver injury by driving with psychoactive substances

    DEFF Research Database (Denmark)

    Hels, Tove; Lyckegaard, Allan; Bernhoft, Inger Marie;

    2013-01-01

    approximated by odds ratios and calculated by logistic regression. The estimates were adjusted for age, gender and country. The highest risk of the driver being severely injured was associated with driving positive for high concentrations of alcohol (≥0.8 g/L), alone or in combination with other psychoactive......Driving with alcohol and other psychoactive substances imposes an increased risk of severe injury accidents. In a population-based case-control design, the relative risks of severe driver injury (MAIS ≥ 2) by driving with ten substance groups were approximated by odds ratios (alcohol, amphetamines...... (N = 2490) were collected from severely injured drivers of passenger cars or vans in selected hospitals in various regions of the countries. Control samples (N = 15,832) were sampled in a uniform sampling scheme stratified according to country, time, road type and season. Relative risks were...

  20. Freshwater microalgae harvested via flocculation induced by pH decrease

    OpenAIRE

    Liu, Jiexia; Zhu, Yi; Tao, Yujun; Zhang, Yuanming; Li, Aifen; Li, Tao; Sang, Ming; Zhang, Chengwu

    2013-01-01

    Background Recent studies have demonstrated that microalga has been widely regarded as one of the most promising raw materials of biofuels. However, lack of an economical, efficient and convenient method to harvest microalgae is a bottleneck to boost their full-scale application. Many methods of harvesting microalgae, including mechanical, electrical, biological and chemical based, have been studied to overcome this hurdle. Results A new flocculation method induced by decreasing pH value of g...

  1. A step-by-step procedure for pH model construction in aquatic systems

    Directory of Open Access Journals (Sweden)

    A. F. Hofmann

    2008-02-01

    Full Text Available We present, by means of a simple example, a comprehensive step-by-step procedure to consistently derive a pH model of aquatic systems. As pH modelling is inherently complex, we make every step of the model generation process explicit, thus ensuring conceptual, mathematical, and chemical correctness. Summed quantities, such as total inorganic carbon and total alkalinity, and the influences of modeled processes on them are consistently derived. The different time scales of processes involved in the pH problem (biological and physical reactions: days; aquatic chemical reactions: fractions of seconds give rise to a stiff equation system. Subsequent reformulations of the system reduce its stiffness, accepting higher non-linear algebraic complexity. The model is reformulated until numerically and computationally simple dynamical solutions, like a variation of the operator splitting approach (OSA and the direct substitution approach (DSA, are obtained. As several solution methods are pointed out, connections between previous pH modelling approaches are established. The final reformulation of the system according to the DSA allows for quantification of the influences of kinetic processes on the rate of change of proton concentration in models containing multiple biogeochemical processes. These influences are calculated including the effect of re-equilibration of the system due to a set of acid-base reactions in local equilibrium. This possibility of quantifying influences of modeled processes on the pH makes the end-product of the described model generation procedure a powerful tool for understanding the internal pH dynamics of aquatic systems.

  2. Segregation of metals-containing wastewater by pH

    International Nuclear Information System (INIS)

    A pH-based sampling system has shown that there is a high correlation between low pH and metals contamination for the wastewater from the 4500 area (manhole 190) and the 2000 area (pump station). Wastewater from the Radiochemical Engineering Development Center (REDC) and the High Flux Isotope Reactor (HFIR) has not shown any metals concentrations above the National Pollutant Discharge Elimination System (NPDES) permit limits for the Nonradiological Wastewater Treatment Plant (NRWTP). It is recommended that pH be used as the diversion criteria for wastewater from manhole 190 and the pump station to be sent to the metals tank of the NRWTP. Any wastewater with a pH less than 6.0 or greater than 10.0 should be sent to the metals tank. Based on the results of 29 weeks of sampling, it is expected that on the order of 36m3/wk (9500 gal/wk) of wastewater will be diverted to the metals tank of the NRWTP. Wastewater from REDC and HFIR can be sent to the nonmetals tank, but it should be sampled periodically and analyzed by Inductively Coupled Plasma (ICP) spectrophotometer to confirm that the metals concentration is not increasing. 1 ref., 2 figs., 9 tabs

  3. External and internal contamination by radioactive substances (tutorial)

    OpenAIRE

    Kučerová, Lenka

    2010-01-01

    The text concerns the creation of a complete education programme focussing on internal and external contamination by radioactive substances. The education programme is composed of several chapters explaining the given problem to the student. The first part of the text explains certain basic facts concerning ionizing radiation, radioactivity, and the quantities characterizing these phenomena. Further, the text explains the effects of ionizing radiation on the human body. The third section desc...

  4. Anoxic Biodegradation of Isosaccharinic Acids at Alkaline pH by Natural Microbial Communities.

    Directory of Open Access Journals (Sweden)

    Simon P Rout

    Full Text Available One design concept for the long-term management of the UK's intermediate level radioactive wastes (ILW is disposal to a cementitious geological disposal facility (GDF. Under the alkaline (10.013.0 anoxic conditions expected within a GDF, cellulosic wastes will undergo chemical hydrolysis. The resulting cellulose degradation products (CDP are dominated by α- and β-isosaccharinic acids (ISA, which present an organic carbon source that may enable subsequent microbial colonisation of a GDF. Microcosms established from neutral, near-surface sediments demonstrated complete ISA degradation under methanogenic conditions up to pH 10.0. Degradation decreased as pH increased, with β-ISA fermentation more heavily influenced than α-ISA. This reduction in degradation rate was accompanied by a shift in microbial population away from organisms related to Clostridium sporosphaeroides to a more diverse Clostridial community. The increase in pH to 10.0 saw an increase in detection of Alcaligenes aquatilis and a dominance of hydrogenotrophic methanogens within the Archaeal population. Methane was generated up to pH 10.0 with acetate accumulation at higher pH values reflecting a reduced detection of acetoclastic methanogens. An increase in pH to 11.0 resulted in the accumulation of ISA, the absence of methanogenesis and the loss of biomass from the system. This study is the first to demonstrate methanogenesis from ISA by near surface microbial communities not previously exposed to these compounds up to and including pH 10.0.

  5. Study on the complexation of humic substances with calcium ion by ion selective electrode method

    International Nuclear Information System (INIS)

    Introduction: Humic substances (HS), which are one of main organic components in soil and aquatic environment, can influence the migration and fate of nuclides through formation of complexes. To quantitatively describe such complex formation, it is essential to consider the formation of major dissolved constituents ions, such as alkali or alkali earth ions, with HSUI. This paper reports the result on the study of the complex formation of calcium ion with soil HS and polyacrylic acid, where polyacrylic acid is selected to observed the effect of heterogeneous composition of HS. Experimental: As an initial solution for the titration experiment, the fixed amounts of calcium ion, NaNO3 solution and HS or PAA were mixed in a 150 mL plastic bottle, which was covered with Laboatory Film (Parafilm 'M'). Then, a fixed amount of NaOH solution was added step by step and the concentration of calcium ion and pH in solution were measured (IM-40S ion meter, DKK.TOA CORP. Japan) simultaneously after each addition. All the experiments were conducted in the 0.01 mol/L NaNO3 solution at 298.2 K in temperature under Ar atmosphere. The humic substances, Elliott soil humic acid (HA) (Cat.No.1sl02H) and Elliott soil Fulvic acid (FA) (Cat.No. lsl02H ), were obtained from International Humic Substances Society(IHSS). Polyacrylic acids (PAA) were obtained from polyscience Inc.(M.W. ca. 450.000). The other chemicals are of analytical grade. De-ionized water (Milli-Q Pureline, Yamato, Japan) was used to prepare the solution. Results and discussion: Fig. 1. shows tile typical titration curves of 500 mg/L HA containing 0.00, 6.24, 20.4, 41.6 mg/L total calcium ion in 0.010 mol/L NaN3 at 298.2 K under Ar atmosphere. The differences between the titration curves of the solution with and without calcium ion indicate the formation of complex with HA. Fig. 1 also shows the plots of the concentration of free calcium ion versus the amounts of added NaOH obtained from the titration of the solution with

  6. Input of trace substances to coniferous forests by fog interception at high elevations of Black Forest

    International Nuclear Information System (INIS)

    The deposition of trace substances to a coniferous forest has been estimated by means of a one-dimensional cloud droplet deposition model. For a period of 21 months the liquid water content has been measured and 89 samples of cloud water from the weather station Feldberg have been analysed for chemical composition. These data and meteorological routine observations have been used as input parameters for the deposition model. Deposition calculations to a 40 years old coniferous forest for the period 1982-1991 showed that the cloud water deposition amounts to 33% of the precipitation amount on the average and varies between 23 and 43% in single years. The highest cloud water deposition rates occur during fall and winter. The trace substance concentration in cloud water has been found to be higher than in precipitation, by a factor between 6 and 12, depending on the type of ions. Typically seasonal variations of normalized ion concentrations could be shown to exist as well as dependencies on wind direction. Air mass transport from the industries of the Stuttgart area resulted in higher trace substance concentrations in cloud water. The deposition of trace substances via fog interception during the summer months is as high and in the winter months higher than that by wet deposition. The forests at high elevations of Black Forest are charged appreciably by fog interception. (orig.). 31 figs., 5 tabs., 39 refs

  7. A step-by-step procedure for pH model construction in aquatic systems

    Directory of Open Access Journals (Sweden)

    A. F. Hofmann

    2007-10-01

    Full Text Available We present, by means of a simple example, a comprehensive step-by-step procedure to consistently derive a pH model of aquatic systems. As pH modeling is inherently complex, we make every step of the model generation process explicit, thus ensuring conceptual, mathematical, and chemical correctness. Summed quantities, such as total inorganic carbon and total alkalinity, and the influences of modeled processes on them are consistently derived. The model is subsequently reformulated until numerically and computationally simple dynamical solutions, like a variation of the operator splitting approach (OSA and the direct substitution approach (DSA, are obtained. As several solution methods are pointed out, connections between previous pH modelling approaches are established. The final reformulation of the system according to the DSA allows for quantification of the influences of kinetic processes on the rate of change of proton concentration in models containing multiple biogeochemical processes. These influences are calculated including the effect of re-equilibration of the system due to a set of acid-base reactions in local equilibrium. This possibility of quantifying influences of modeled processes on the pH makes the end-product of the described model generation procedure a powerful tool for understanding the internal pH dynamics of aquatic systems.

  8. Sex differences in the cumulative incidence of substance use by birth cohort

    OpenAIRE

    Colell Ortega, Esther, 1961-; S??nchez Niub??, Albert; Domingo i Salvany, Ant??nia

    2013-01-01

    BACKGROUND: Men present higher overall rates of substance use and abuse than women; yet, evidence suggests that an increase of substance use by the younger cohorts of women in recent decades is narrowing this gap in western societies. Moreover, younger cohorts may also be reporting earlier initiation of substance use, representing an increased risk for developing substance-related problems. With this study we intend to identify changes in the patterns of substance use of men and women in Spai...

  9. In vitro antimicrobial activity of auxiliary chemical substances and natural extracts on Candida albicans and Enterococcus faecalis in root canals

    Directory of Open Access Journals (Sweden)

    Marcia Carneiro Valera

    2013-04-01

    Full Text Available Objective: The aim of this study was to evaluate the antimicrobial activity of auxiliary chemical substances and natural extracts on Candida albicans and Enterococcus faecalis inoculated in root canals. Material and Methods: Seventy-two human tooth roots were contaminated with C. albicans and E. faecalis for 21 days. The groups were divided according to the auxiliary chemical substance into: G1 2.5% sodium hypochlorite (NaOCl, G2 2% chlorhexidine gel (CHX, G3 castor oil, G4 glycolic Aloe vera extract, G5 glycolic ginger extract, and G6 sterile saline (control. The samples of the root canal were collected at different intervals: confirmation collection, at 21 days after contamination; 1st collection, after instrumentation; and 2nd collection, seven days after instrumentation. Microbiological samples were grown in culture medium and incubated at 37°C for 48 hours. Results: The results were submitted to the Kruskal-Wallis and Dunn (5% statistical tests. NaOCl and CHX completely eliminated the microorganisms of the root canals. Castor oil and ginger significantly reduced the number of CFU of the tested bacteria. Reduction of CFU/mL at the 1st and 2nd collections for groups G1, G2, G3 and G4 was greater in comparison to groups G5 and G6. Conclusion: It was concluded that 2.5% sodium hypochlorite and 2% chlorhexidine gel were more effective in eliminating C. albicans and E. faecalis, followed by the castor oil and glycolic ginger extract. The Aloe vera extract showed no antimicrobial activity.

  10. Preferences for treatment setting by substance users in India

    Directory of Open Access Journals (Sweden)

    Anju Dhawan

    2016-01-01

    Full Text Available Background: Drug and alcohol use is a growing public health concern for India. Treatment services delivery for substance use disorders is available through three sectors viz. Government (GO centres under Ministry of Health and FW, Non-Government (NGO under Ministry of Social Justice and Empowerment and the private sector. Information on ttreatment utilisation and preferences of treatment settings by substance users are not available for India. Methods: A performa was filled up prospectively for each consecutive new patient seeking treatment for drug/alcohol use (excluding tobacco at De-addiction centres funded by MOH&FW; NGOs under MoSJE and private psychiatrists between 15 th July to 15 th October, 2011. All data available for 182 drug using persons from private, 1228 persons from 35 NGOs and 1700 persons from GO organizations were entered into SPSS-21.0, data quality checks performed and analysed. Results: There was a variance in the population profile in the three sectors providing treatment delivery for substance users in India. Treatment seeking for illicit drugs (heroin, opiates and cannabis was higher in GO sector; injection drug use was higher in NGO sector while alcohol was higher in private sector. Conclusions: Strengthening linkages between GO and NGO sector is important for an improved coverage and quality of treatment services in the country. The Andersen′s Behavioural Model as theoretical background to clarify some issues in analyzing with larger datasets is warranted.

  11. Endocrine disrupting chemicals and other substances of concern in food contact materials: an updated review of exposure, effect and risk assessment.

    Science.gov (United States)

    Muncke, Jane

    2011-10-01

    Food contact materials (FCM) are an underestimated source of chemical food contaminants and a potentially relevant route of human exposure to endocrine disrupting chemicals (EDCs). Quantifying the exposure of the general population to substances from FCM relies on estimates of food consumption and leaching into food. Recent studies using polycarbonate plastics show that food simulants do not always predict worst-case leaching of bisphenol A, a common FCM substance. Also, exposure of children to FCM substances is not always realistically predicted using the common conventions and thus possibly misjudged. Further, the exposure of the whole population to substances leaching into dry foods is underestimated. Consumers are exposed to low levels of substances from FCM across their entire lives. Effects of these compounds currently are assessed with a focus on mutagenicity and genotoxicity. This approach however neglects integrating recent new toxicological findings, like endocrine disruption, mixture toxicity, and developmental toxicity. According to these new toxicology paradigms women of childbearing age and during pregnancy are a new sensitive population group requiring more attention. Furthermore, in overweight and obese persons a change in the metabolism of xenobiotics is observed, possibly implying that this group of consumers is insufficiently protected by current risk assessment practice. Innovations in FCM risk assessment should therefore include routine testing for EDCs and an assessment of the whole migrate toxicity of a food packaging, taking into account all sensitive population groups. In this article I focus on recent issues of interest concerning either exposure to or effects of FCM-related substances. Further, I review the use of benzophenones and organotins, two groups of known or suspected EDCs, in FCM authorized in the US and EU. PMID:21073950

  12. Assessing the potential hazard of chemical substances for the terrestrial environment. Development of hazard classification criteria and quantitative environmental indicators.

    Science.gov (United States)

    Tarazona, J V; Fresno, A; Aycard, S; Ramos, C; Vega, M M; Carbonell, G

    2000-03-20

    Hazard assessment constitutes an essential tool in order to evaluate the potential effects of chemical substances on organisms and ecosystems. It includes as a first step, hazard identification, which must detect the potential dangers of the substance (i.e. the kind of effects that the substance may produce), and a second step to quantify each danger and to set the expected dose/response relationships. Hazard assessment plays a key role in the regulation of chemical substances, including pollution control and sustainable development. However, the aquatic environment has largely received more attention than terrestrial ecosystems. This paper presents the extrapolation of several basic concepts from the aquatic to the terrestrial compartment, and suggests possibilities for their regulatory use. Two specific proposals are discussed. The first focuses on the scientific basis of the hazard identification-classification criteria included in the EU regulations and their extrapolation to the terrestrial environment. The second focuses on the OECD programme for environmental indicators and the development of a soil pollution pressure indicator to quantify the potential hazards for the soil compartment and its associated terrestrial ecosystem related to the toxic chemicals applied deliberately (i.e. pesticides) or not (i.e. heavy metals in sludge-based fertilisers; industrial spills) to the soil. PMID:10803544

  13. pH modeling for maximum dissolved organic matter removal by enhanced coagulation

    Institute of Scientific and Technical Information of China (English)

    Jiankun Xie; Dongsheng Wang; John van Leeuwen; Yanmei Zhao; Linan Xing; Christopher W. K. Chow

    2012-01-01

    Correlations between raw water characteristics and pH after enhanced coagulation to maximize dissolved organic matter (DOM)removal using four typical coagulants (FeCl3,Al2(SO4)3,polyaluminum chloride (PAC1) and high performance polyaluminum chloride (HPAC)) without pH control were investigated.These correlations were analyzed on the basis of the raw water quality and the chemical and physical fractionations of DOM of thirteen Chinese source waters over three seasons.It was found that the final pH after enhanced coagulation for each of the four coagulants was influenced by the content of removable DOM (i.e.hydrophobic,and higher apparent molecular weight (AMW) DOM),the alkalinity and the initial pH of raw water.A set of feed-forward semi-empirical models relating the final pH after enhanced coagulation for each of the four coagulants with the raw water characteristics were developed and optimized based on correlation analysis.The established models were preliminarily validated for prediction purposes,and it was found that the deviation between the predicted data and actual data was low.This result demonstrated the potential for the application of these models in practical operation of drinking water treatment plants.

  14. Suppressive effects of coffee on the SOS responses induced by UV and chemical mutagens

    International Nuclear Information System (INIS)

    SOS-inducing activity of UV or chemical mutagens was strongly suppressed by instant coffee in Salmonella typhimurium TA1535/pSK1002. As decaffeinated instant coffee showed a similarly strong suppressive effect, it would seem that caffeine, a known inhibitor of SOS responses, is not responsible for the effect observed. The suppression was also shown by freshly brewed coffee extracts. However, the suppression was absent in green coffee-bean extracts. These results suggest that coffee contains some substance(s) which, apart from caffeine, suppresses SOS-inducing activity of UV or chemical mutagens and that the suppressive substance(s) are produced by roasting coffee beans. (Auth.)

  15. Peptide hydrogelation triggered by enzymatic induced pH switch

    Science.gov (United States)

    Cheng, Wei; Li, Ying

    2016-07-01

    It remains challenging to develop methods that can precisely control the self-assembling kinetics and thermodynamics of peptide hydrogelators to achieve hydrogels with optimal properties. Here we report the hydrogelation of peptide hydrogelators by an enzymatically induced pH switch, which involves the combination of glucose oxidase and catalase with D-glucose as the substrate, in which both the gelation kinetics and thermodynamics can be controlled by the concentrations of D-glucose. This novel hydrogelation method could result in hydrogels with higher mechanical stability and lower hydrogelation concentrations. We further illustrate the application of this hydrogelation method to differentiate different D-glucose levels.

  16. A General Method for the Rapid Determination of Carbon-14- and Hydrogen-3-Labelled Substances by Gas Chromatography

    International Nuclear Information System (INIS)

    A method is described for the determination of 14C- and 3H- labelled substances by gas chromatography using different size flow counters. The method of cracking substances in a current of hydrogen gas is especially suitable for 3H-labelled compounds because it is free from the disadvantages encountered when the substances are first oxidized and the water formed subsequently converted. The general applicability of this method is shown for different classes of compounds. The analysis is independent of the chemical composition of the compound. By using a part oi the apparatus very rapid analyses of vaporizable 14C- and apparently all 3H-labelled substances can be made by direct injection into the reaction chamber. The apparatus can also be used for the oxidation procedure. (author)

  17. SOLUPLOT, Eh-pH Diagram, aO2-pH Diagram Plots for Aqueous Chemical Systems

    International Nuclear Information System (INIS)

    1 - Description of problem or function: SOLUPLOT is a program designed to calculate and plot complex potential - pH diagrams and log oxygen activity - pH diagrams for aqueous chemical systems, considering speciation of ligands, from free energy and thermodynamic activity data. These diagrams, commonly referred to as Eh-pH and aO2-pH diagrams, respectively, define areas of predominance in Eh-pH diagrams or aO2-pH space for chemical species of a chemical system at equilibrium. Over an area of predominance, one predominant species is at greater activity than the other species of the system considered. The diagram axes, pH (a measure of hydrogen ion activity) and either Eh or log aO2 (measures of the tendency toward either oxidation or reduction), are parameters commonly applied in describing the chemistry of aqueous systems. 2 - Method of solution: SOLUPLOT calculates a diagram involving the speciation of ligands in three general steps. First the speciation of a pH-dependent ligand system, if specified in the input data, is calculated. Since this system is solely pH-dependent, areas of predominance are defined by constant pH lines which divide the diagram vertically into a number of rectangular subsections. Secondly the program calculates the speciation of an Eh-pH- dependent ligand system, if so specified in the input data. This speciation may be represented by vertical, horizontal, and sloping bounds. The initial diagram is now effectively divided into a number of sub-diagrams, each representing the intersection of the area of predominance of one Eh-pH-dependent ligand species. Finally the program takes each sub-diagram separately and calculates the speciation of the main system. Within each sub-diagram the program actually calculates two speciations, one among all the species in the main system (the solid-aqueous diagram), and one among only the aqueous species (the aqueous species diagram). The main system within a sub-diagram includes main system species, all non

  18. Formation of slow-reacting substance by guinea pig immunoglobulins.

    Science.gov (United States)

    Jancar, S.; Akimura, O. K.; Dias da Silva, W.

    1976-01-01

    The capacity of guinea pig antibodies to mediate the antigen-induced release of slow-reacting substance (SRS) in the rat peritoneal cavity is restricted to IgG2 and, to a lesser extent, to IgG1 populations of immunoglobulin. IgM and homocytotropic antibody of the reaginic type lacked this activity. The process was partially blocked by previous decomplementation of the rats, was not affected by previous reduction of the circulating leukocytes, and was partially suppressed by previous depletion of circulating platelets with an antiserum to rat platelets. PMID:11696

  19. Fiscal 1997 report on the results of the international standardization R and D. Measurement of ultra-micro chemical substances and measuring methods of hormone effects; 1997 nendo seika hokokusho kokusai hyojun soseigata kenkyu kaihatsu. Chobiryo kagaku busshitsu no keisoku horumon eikyo sayo sokuteiho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Concerning the measurement system of ultra-micro hazardous chemical substances in the global environment, the paper examined the present situation of chemical substances such as dioxins, made an experimental study on the method to analyze dioxins in exhaust gas from an aspect of international consistency, and worked out a JIS draft. As to the standard measuring method of hormone effects of chemical substances, the paper developed the competitive bonding experiment system to measure bonding ability of chemical substances to homo sapiens estrogen receptor (ER). By measuring ER bonding ability of 78 kinds of chemical substances, the measuring method was developed. In the development of the assay system for detection of hormone-like compounds, the assay system with transfer activity via estrogen receptor as an index was established using cultured cells and yeast. Further, the development was made of a measuring method of receptor bonding activity of hormone-like substances. 33 refs., 151 figs., 66 tabs.

  20. Compensation of damage caused by diverted nuclear substances

    International Nuclear Information System (INIS)

    This paper provides a comprehensive analysis of the insurance system for nuclear liability. As a rule, if nuclear fuel, radioactive products or waste are governed by nuclear energy law providing for strict and channelled liability, their legal holder will pay for damage arising from them anywhere within 20 years after theft or diversion and 10 years after the nuclear incident. In most countries, atomic liability insurers will implicitly grant their cover through policies underwritten by legal holders. If diverted substances have a low specific radioactivity, their legal holder remains liable according to common law and insurance policies cover this conventional liability. (NEA)

  1. Erythema multiforme possibly triggered by food substances in a dog.

    Science.gov (United States)

    Itoh, Teruo; Nibe, Kazumi; Kojimoto, Atsuko; Mikawa, Mayumi; Mikawa, Kazuhiro; Uchida, Kazuyuki; Shii, Hiroki

    2006-08-01

    A 5-year-old female border collie presented with erythematous skin lesions at the axillae, groin, mucocutaneous junctions, and pinnae. Biopsy revealed lymphocytic interface dermatitis with hydropic degeneration of basal cells and keratinocyte apoptosis. Based on gross and histological features, diagnosis of erythema multiforme was made. The disease was resolved by treatment with azathioprine, prednisolone, and a hypoallergenic diet. Finally, the skin lesion was controlled without drug therapy but recurred easily every time commercial foods except the hypoallergenic diet were used, suggesting that food substances triggered this outbreak. PMID:16953090

  2. Tracking chemicals in products around the world: introduction of a dynamic substance flow analysis model and application to PCBs.

    Science.gov (United States)

    Li, Li; Wania, Frank

    2016-09-01

    Dynamically tracking flows and stocks of problematic chemicals in products (CiPs) in the global anthroposphere is essential to understanding their environmental fates and risks. The complex behavior of CiPs during production, use and waste disposal makes this a challenging task. Here we introduce and describe a dynamic substance flow model, named Chemicals in Products - Comprehensive Anthropospheric Fate Estimation (CiP-CAFE), which facilitates the quantification of time-variant flows and stocks of CiPs within and between seven interconnected world regions and the generation of global scale emission estimates. We applied CiP-CAFE to polychlorinated biphenyls (PCBs), first to evaluate its ability to reproduce previously reported global-scale atmospheric emission inventories and second to illustrate its potential applications and merits. CiP-CAFE quantifies the pathways of PCBs during production, use and waste disposal stages, thereby deducing the temporal evolution of in-use and waste stocks and identifying their long-term final sinks. Time-variant estimates of PCB emissions into air, water and soil can be attributed to different processes and be fed directly into a global fate and transport model. By capturing the international movement of PCBs as technical chemicals, and in products and waste, CiP-CAFE reveals that the extent of global dispersal caused by humans is larger than that occurring in the natural environment. Sensitivity analysis indicates that the model output is most sensitive to the PCB production volume and the lifetime of PCB-containing products, suggesting that a shortening of that lifetime is key to reducing future PCB emissions. PMID:27431909

  3. Detection of Baking Soda in Flat Bread by Direct pH Metery and Alkalinity Measurement

    Science.gov (United States)

    Jahed Khaniki, G. H. R.; Vaezi, F.; Yunesian, M.; Nabizadeh, R.; Paseban, G. H. A.

    The objective of this study is evaluation of direct pH metery and alkalinity measurement methods for determination of baking soda in lavash bread (a kind of flat bread) in order to introduce and recommend a good practice of control. For running the experiments, various samples of lavash bread having different concentrations of baking soda were prepared. Ten grams of each sample were mixed with distilled water and then the prepared solutions were filtrated. The filtrates were then analyzed for pH and total alkalinity according to the distractions described in Standard Methods. Results show a significant correlation between the pH values of bread samples and the amount of baking soda. Also, a positive correlation has been observed between the alkalinity of bread samples and used baking soda. By comparing the R2-values specified for these two methods it could be concluded that the direct pH metery method is more reasonable. Furthermore, by this simple method it is possible to accelerate the detection of minute amounts of this chemical in bread.

  4. Extraction of extracellular polymeric substances (EPS) from anaerobic granular sludges: comparison of chemical and physical extraction protocols

    OpenAIRE

    Abzac, D', P.; Bordas, F; Van Hullebusch, E.; Lens, P. N. L.; Guibaud, G.

    2010-01-01

    The characteristics of the extracellular polymeric substances (EPS) extracted with nine different extraction protocols from four different types of anaerobic granular sludge were studied. The efficiency of four physical (sonication, heating, cationic exchange resin (CER), and CER associated with sonication) and four chemical (ethylenediaminetetraacetic acid, ethanol, formaldehyde combined with heating, or NaOH) EPS extraction methods was compared to a control extraction protocols (i.e., centr...

  5. Effect of freeze-thaw cycling on the chemical composition of aqueous solutions of organic substances

    International Nuclear Information System (INIS)

    By means of spectrophotometry and chemical analysis, it was found that multiply repeated freezing-thawing cycles for aqueous solutions of carbohydrates, choline chloride, and diphenylpicrylhydrazyl (DPPH) alter the chemical composition of the final solutions. In most cases, one or two freeze-thaw cycles are shown to result in the same changes as those observed upon γ irradiation with absorbed doses of 200-300 Gy. The DPPH decay detected during the repetition of this treatment suggests that the degradation of organic molecules involves the stage of formation of free radicals. It was assumed that the cause of the observed processes is cavitation

  6. Fiber optic chemical sensor systems for monitoring pH changes in concrete

    Science.gov (United States)

    Basheer, Muhammed P.; Grattan, Kenneth T. V.; Sun, Tong; Long, Adrian E.; McPolin, Daniel; Xie, Weiguo

    2004-12-01

    Carbonation-induced corrosion of steel is one of the principal causes of deterioration of reinforced concrete structures. When concrete carbonates, its pH decreases from a value in excess of 12.6 to less than 9 and, hence, a measure of the pH is an indicator of the degree of carbonation. This paper describes the development, testing and evaluation of two types of fibre optic sensors for the pH monitoring. One of these used a sol-gel based probe tip, into which an indicator dye has been introduced and the second used a disc containing an indicator operating over a narrower range of pH with shorter lifetime. Both were connected to a portable spectrometer system, which is used to monitor the spectral changes in optical absorption of the probe tip. A white light source to interrogate the active elements is used as the systems operate in the visible part of the spectrum. The two types of sensors have been found to be sensitive to the changes in pH due to carbonation, but the response time depended on the thickness of the coating material in the case of the sol-gel sensor. The durability of the sensors is still under investigation. The disc type sensor has a life span of approximately 1 month and, hence, it is not suitable for embedding in concrete for long-term monitoring of pH changes. However, it can be used for assessing the pH in vivo. The harder sol-gel is more durable and, hence, has a slower, but acceptable response time.

  7. Influência pH na reposta de sementes de plantas daninhas a substâncias promotoras de germinação Influence of pH on the action of chemicals on weed seeds

    Directory of Open Access Journals (Sweden)

    Ricardo Carmona

    1997-01-01

    Full Text Available Determinou-se o efeito do pH na ação de algumas subst âncias promotoras de germinação em sementes de Chenopodium album L., Avena fatua L. e Rumex crispus L. A azida de sódio (A, nitrato de potássio + etileno (NE, NE + A, NE + A + tiuréia + peróxido de hidrogênio foram testados em solo (em bandej as e em papel (in vitro com soluções tampão em ambiente controlado. O efeito do NE no estímulo à germinação de sementes não foi afetado pelo pH na faixa de 3 a 9. A azida de sódio foi a substância que mais afetou as sementes, sendo este efeito pH dependente. Este composto foi extremamente deletério em sementes de C. album e A. fatua em solo ácido (pH 4,0, enquanto em solo básico ele estimulou a germinação em sementes de A. fatua, através da superação da dormência A combinação de NE + A em pH 6,2 inibiu a germinação de C. album e A. fatua, mostrando um antagonismo entre estes compostos. A mistura dos cinco compostos reduziu a influência do pH na ação deletéria da azida de sódio. O efeito deletério da azida foi menos afetado pela temperatura do que sua ação como superador de dormência. A solução extraída do solo não afetou a resposta de tratamentos químicos in vitro em diferentes temperaturas comparado a soluções tampão em pH semelhante. Discute-se a influência das características do solo na eficácia de substâncias químicas como superadores de dormência ou tratamentos deletérios às sementes.The effects of pH on the action of some dormancy-relieving chemicals were investi gated on seeds of Chenopodium album, Avena fatua and Rumex crispus. Sodium azide (A, potassium nitrate + ethephon (NE, NE + A, NE + A + thiourea + hydrogen peroxide were tested in soil trays or in paper (in vitro with buffer solutions in controlled environment. The response to NE was not affected by pH from 3 to 9. Sodium azide had the gre ate st effect on seed decline, but its effect was pH-dependent. This compound was extremely

  8. 77 FR 66149 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2012-11-02

    ... Register issue of April 24, 1990 (55 FR 17376) (April 24, 1990 SNUR). Consult that preamble for further... a raw material for production of copper chemicals and as a raw material for the production of animal... (PCDFs) by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) study...

  9. Chemical and spectroscopic characterization of humic substances isolated from South- Bohemian peat

    Czech Academy of Sciences Publication Activity Database

    Enev, V.; Novák, František; Klučáková, M.

    Ioannina : University of Ioannina, 2014. s. 226-227. [Meeting of the International Humic Substances Society. Natural Organic Matter: Structure-Dynamics-Innovative Applications /17./. 01.09.2014-05.09.2014, Ioannina] Grant ostatní: GA MŠk(CZ) LO1211 Institutional support: RVO:60077344 Keywords : humic substances * UV/ Vis * FTIR spectroscopy * fluorescence spectroscopy * absorption and fluorescence coefficients Subject RIV: DF - Soil Science

  10. Self-mutilation induced by psychotropic substances: a systematic review.

    Science.gov (United States)

    Gahr, Maximilian; Plener, Paul Lukas; Kölle, Markus Alexander; Freudenmann, Roland Wolfgang; Schönfeldt-Lecuona, Carlos

    2012-12-30

    Self-mutilation (SM) not only occurs among patients with schizophrenia, personality disorders or transsexuality but also as a phenomenon induced by psychotropic substances (PS). We intended to find characteristics of patients at risk to perform SM induced by PS (SMIPS), frequent PS within this phenomenon and typical presentations of SMIPS. A systematic review of the literature (including Medline, the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials and Scopus) was conducted. On October 2011 we identified 26 cases (23 publications) of SM related to PS. Majority of patients (85%) was male, mean age was 30 years (median 41 years). Seventy-three percent of patients developed SM subsequent to the use of one PS, 27% presented SM after the use of more than one PS. Alcohol (25%), hallucinogens (25%) and amphetamines (22%) were found most frequently among the reported substances. Major impairment was present in 80%. Our findings suggest male sex, young age, a previous history of abuse of PS and the current use of alcohol, hallucinogens or amphetamines to favour SMIPS. PMID:22841344

  11. Reducing groundwater pollution by toxic substances: Procedures and policies

    Science.gov (United States)

    Waterstone, Marvin

    1987-11-01

    One major source of water-related health problems is the improper disposal of toxic substances in the environment. Toxic materials leaching from unregulated and unlined pits, ponds, lagoons, and landfills have created a widespread environmental nightmare in the United States and many other parts of the world. At present, there are two major and interrelated components of this problem in the United States. The first is the issue of cleaning up abandoned disposal sites that pose actual or potential threats to water supplies. The second aspect of the problem concerns the necessity of siting proper management, treatment, or disposal facilities in the future. Priorities must be set to allow efficient, effective, and equitable allocation of the scarce resources that are available for accomplishing these tasks. This article examines a number of the issues involved in setting these priorities, and presents the results obtained from a study of risk estimation and evaluation in the context of groundwater contamination by toxic substances. The article introduces a new concept of risk estimation, which is shown to produce more accurate and credible risk analyses. Finally, the relationships between risk credibility and public perceptions of procedural fairness and equity are examined as these factors bear on the institutional aspects of implementing policies for site cleanup and/or facility siting.

  12. Production of bacteriocin-like substances by lactic acid bacteria isolated from regional ovine cheese

    Directory of Open Access Journals (Sweden)

    Cássia Regina Nespolo

    2010-12-01

    Full Text Available Lactic acid bacteria (LAB were isolated from ovine milk and cheeses manufactured in the South Region of Brazil. Among 112 bacterial isolates investigated, 59 were chosen through a screening for LAB. Among these 59 strains of LAB, 21% showed antimicrobial, proteolytic and lipolytic activities. Based on this screening, Lactobacillus plantarum LCN 17 and Lactobacillus rhamnosus LCN 43 were selected and tested for the production of bacteriocin-like substances (BLS. The BLS produced by both isolates showed antimicrobial activity against Listeria monocytogenes, whereas that produced by L. plantarum LCN 17 presented higher stability to different temperature, pH and enzyme treatments. These strains present potential for production of BLS, and for use as starter cultures.

  13. Characterization of laser-tissue interaction processes by low-boiling emitted substances

    Science.gov (United States)

    Weigmann, Hans-Juergen; Lademann, Juergen; Serfling, Ulrike; Lehnert, W.; Sterry, Wolfram; Meffert, H.

    1996-01-01

    Main point in this study was the investigation of the gaseous and low-boiling substances produced in the laser plume during cw CO2 laser and XeCl laser irradiation of tissue by gas chromatography (GC)/mass spectrometry. The characteristic emitted amounts of chemicals were determined quantitatively using porcine muscular tissue. The produced components were used to determine the character of the chemical reaction conditions inside the interaction zone. It was found that the temperature, and the water content of the tissue are the main parameter determining kind and amount of the emitted substances. The relative intensity of the GC peak of benzene corresponds to a high temperature inside the interaction area while a relative strong methylbutanal peak is connected with a lower temperature which favors Maillard type reaction products. The water content of the tissue determines the extent of oxidation processes during laser tissue interaction. For that reason the moisture in the tissue is the most important parameter to reduce the emission of harmful chemicals in the laser plume. The same methods of investigation are applicable to characterize the interaction of a controlled and an uncontrolled rf electrosurgery device with tissue. The results obtained with model tissue are in agreement with the situation characteristic in laser surgery.

  14. Substances in human urine that strongly inhibit bacterial mutagenicity of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and related heterocyclic amines.

    Science.gov (United States)

    Malaveille, C; Hautefeuille, A; Brun, G; Vineis, P; Bartsch, H

    1992-12-01

    Extracts of human urine were shown to contain substances that strongly inhibited the liver S9-mediated mutagenicity of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in Salmonella typhimurium TA98 strain in a liquid incubation assay. The inhibitory effect was unrelated to cytotoxicity and was similar with urine extracts from smokers and non-smokers. Under similar assay conditions, the mutagenicity of the related amino-imidazoazaarenes, 2-amino-3-methyl-imidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]-quinoline and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline was also found to be strongly inhibited by urine extracts. Decreased or enhanced mutagenicity was seen with 2-acetyl-aminofluorene and 2-aminoanthracene depending on the type of assay, and the time of incubation in liquid medium. A weak inhibition of the mutagenicity of 2-nitrofluorene, a direct-acting mutagen, was observed only after a short incubation time. Mutagenicity of 4-nitroquinoline N-oxide was not altered by the presence of urine extracts at concentrations shown to be inhibitory for the mutagenicity of heterocyclic aromatic amines. Our data suggest that the inhibitory substances in urine act through their capacity to non covalently bind the parent heterocyclic and aromatic amines, thus affecting their availability in aqueous medium for diffusion into liver microsomes where metabolic activation takes place. PMID:1473240

  15. Influence of pH value on Cu (II biosorption by lignocellulose peach shell waste material

    Directory of Open Access Journals (Sweden)

    Lopičić Zorica R.

    2013-01-01

    Full Text Available In the last decade, the pollution made by anthropogenic sources has reached large amounts with special attention on heavy metals because of their high toxicity, persistence and bioaccumulation tendency. Since the conventional methods for their removing are either too expensive or create large quantities of toxic sludge, the great attention has been paid to the new technologies such as biosorption, technology that use cheap, abundant, organic waste for sequestering pollutants from contaminated mediums. Among the other factors that affect biosorption process, pH value is one the most important because it directs both the metal solution chemistry as well as the activity of the biomass functional groups. In this paper the influence of pH value on biosorption of Cu (II by unmodified low-cost lignocellulose biosorbent - peach shell (PS particles, have been studied. The chemical composition of PS, point of zero charge (pHPZC as well as its surface morphology is also presented. Results have showed that this biosorbent contains mainly cellulose and lignin, the components that carry the functional groups responsible for metal binding. Its multilayer surface contains many pores and channels that help diffusion in deeper layers and force biosorption process. Point of zero charge determination was performed with three different KNO3 ionic strengths: 0,1M, 0,01M and 0,001M. The obtained value for pHPZC was 4,75±0,1 and showed that this biosorbent is non-sensitive to ionic strength of electrolyte applied. Biosorption experiments were done with peach shell particles whose diameter was -0,5+0,1mm at 25oC . The initial copper (II concentration was 50 mg/dm3 while the biosorbent concentration was 10g/dm3. Experiments were done with and without keeping pH constant. The influence of pH on biosorption process was examined in 2-6 pH range. The percentage of Cu (II removed by PS, reaches its maximum at pH 6, with the 90,43% removing but this percentage can also be

  16. Chemically driven switches for online detection of pH changes in microfluidic devices

    NARCIS (Netherlands)

    Mela, P.; Onclin, S.; Goedbloed, M.H.; Levi, S.A.; Hulst, van N.F.; Berg, van den A.

    2003-01-01

    The internal walls of microfabricated fluidic channels were functionalized with a selfassembled monolayer of Rhodamine B lactam. This molecule has the capability to interconvert between its open fluorescent amide form and the closed non-fluorescent lactam form upon changes of the pH conditions. The

  17. Optimal choice of pH for toxicity and bioaccumulation studies of ionizing organic chemicals

    DEFF Research Database (Denmark)

    Rendal, Cecilie; Kusk, Kresten Ole; Trapp, Stefan

    2011-01-01

    processes were identified to explain the behavior of ionizing compounds with changing pH: the change in lipophilicity when a neutral compound becomes ionized, electrical attraction, and the ion trap. The literature was screened for bioaccumulation and toxicity tests of ionizing organic compounds performed...

  18. 32P assessed phosphate uptake by tomato plants Hebros in relation to soil nutrient substance supplies

    International Nuclear Information System (INIS)

    The uptake of phosphates by tomato plants, cv.Hebros, was assessed by 32P in a vegetation pot experiment. Leached meadow-cinnamon soil was used, taken from a stationary field experiment to which, for a period of eight years, various rates of NPK were applied. As a result of that significant changes occurred in the soil nutrient substance supplies (concerning total and mobile forms of nitrogen, phosphorus, potassium, pH and salts concentration). It was established that the coefficient of phasphate utilization by tomato plants was the highest (19.15%) on soil receiving a N210P210K210 fertilizer application. Long-term fertilization with higher rates at a 1:1:1 NPK ratio increased the content of nutrient substances in the soil, but the coefficient of utilization of available phosphate diminished and was lowest (11.40%) in the case when a N960P960K720 mineral fertilizer rate was applied. Following prolonged mineral fertilization with growing N rates (from 240 up to 720 kg/ha) at a background of P720K210, the coefficient of phosphate utilization by tomato plants also diminished from 16.16 to 12.26%. (author)

  19. Inhibition of propionibacterium acnes by bacteriocin-like inhibitory substances (BLIS) produced by Streptococcus salivarius.

    Science.gov (United States)

    Bowe, Whitney P; Filip, Jennifer C; DiRienzo, Joseph M; Volgina, Alla; Margolis, David J

    2006-10-01

    We report the in vitro inhibition of Propionibacterium acnes (P. acnes) by a bacteriocin-like inhibitory substance (BLIS-like substance) produced by Streptococcus salivarius (S. salivarius). Bacteriocins are proteinaceous substances produced by bacteria that are capable of inhibiting the growth of similar bacterial strains. Unlike classical antibiotics, they have a relatively narrow spectrum of killing activity, resulting in a reduction in the intensity of selection for resistance. These findings suggest that BLIS may potentially be used for its anti-P. acnes activity in the treatment of acne. PMID:17039652

  20. Nitrite fixation by humic substances: Nitrogen-15 nuclear magnetic resonance evidence for potential intermediates in chemodenitrification

    Science.gov (United States)

    Thorn, K.A.; Mikita, M.A.

    2000-01-01

    Studies have suggested that NO2/-, produced during nitrification and denitrification, can become incorporated into soil organic matter and, in one of the processes associated with chemodenitrification, react with organic matter to form trace N gases, including N2O. To gain an understanding of the nitrosation chemistry on a molecular level, soil and aquatic humic substances were reacted with 15N-labeled NaNO2, and analyzed by liquid phase 15N and 13C nuclear magnetic resonance (NMR). The International Humic Substances Society (IHSS) Pahokee peat and peat humic acid were also reacted with Na15NO2 and analyzed by solid-state 15N NMR. In Suwannee River, Armadale, and Laurentian fulvic acids, phenolic rings and activated methylene groups underwent nitrosation to form nitrosophenols (quinone monoximes) and ketoximes, respectively. The oximes underwent Beckmann rearrangements to 2??amides, and Beckmann fragmentations to nitriles. The nitriles in turn underwent hydrolysis to 1??amides. Peaks tentatively identified as imine, indophenol, or azoxybenzene nitrogens were clearly present in spectra of samples nitrosated at pH 6 but diminished at pH 3. The 15N NMR spectrum of the peat humic acid exhibited peaks corresponding with N-nitroso groups in addition to nitrosophenols, ketoximes, and secondary Beckmann reaction products. Formation of N-nitroso groups was more significant in the whole peat compared with the peat humic acid. Carbon-13 NMR analyses also indicated the occurrence of nitrosative demethoxylation in peat and soil humic acids. Reaction of 15N-NH3 fixated fulvic acid with unlabeled NO2/- resulted in nitrosative deamination of aminohydroquinone N, suggesting a previously unrecognized pathway for production of N2 gas in soils fertilized with NH3.Studies have suggested that NO2-, produced during nitrification and denitrification, can become incorporated into soil organic matter and, in one of the processes associated with chemodenitrification, react with organic

  1. Oxidative stability of egg and soy lecithin as affected by transition metal ions and pH in emulsion.

    Science.gov (United States)

    Wang, Guang; Wang, Tong

    2008-12-10

    Oxidative stability of egg and soy lecithin in emulsion was evaluated with two transition metal ions, cupric and ferric ion, at two concentration levels (50 and 500 microM). The effect of pH on lipid oxidation was also examined under these two concentrations for each ion. Egg lecithin (EL) had similar peroxide value (PV) development pattern as soy lecithin (SL) when treated with cupric ion under both acidic and neutral pH. Acidic pH of 3 accelerated oxidation of both EL and SL, especially under high concentration of copper. When treated with ferric ion, EL oxidized much faster than SL did. EL had higher value of thiobarbituric acid-reactive substances (TBARS) than SL, possibly because of its higher content of long-chain polyunsaturated fatty acids (PUFA). Acidic pH accelerated TBARS development for both EL and SL, but EL had more significantly increased values. Cupric ion was more powerful than ferric in catalyzing oxidation of both EL and SL under both acidic and neutral pH conditions as measured by PV and TBARS. Linoleic acid may contribute to higher PV production, however, arachidonic acid and docosahexaenoic acid may have contributed more to TBARS production. Overall, SL showed better oxidative stability than EL under the experimental conditions. This study also suggests that using multiple methods is necessary in properly evaluating lipid oxidative stability. PMID:18991454

  2. Vacuolation induced by unfavorable pH in cyanobacteria

    Institute of Scientific and Technical Information of China (English)

    赵以军; 吴红艳; 郭厚良; 许敏; 程凯; 祝海燕

    2001-01-01

    Six species or strains of cyanobacteria, Anabaena sp. 595, Plectonema boryanum 246, Scytonema hofmanni 248, Nostoc sp. 96, Oscillatoria animlis 284 and Spirulina maxima 438, were cultured in unfavorable pH conditions for vacuole induction. At pH 5.0, 6.5, or 7.0, vacuoles were observed to form in both Anabaena sp. 595 and Plectonema boryanum 246, especially in the former. The vacuolation took place with some morphological changes, such as the cells being inflated, spherical and vacuolated, and with unequalized division. The induced vacuoles in An- abaena sp. 595 and Plectonema boryanum 246 were in spherical shape and in rather transparent appearance under a phase microscope. For Scytonema hofmanni 248, it was less sensitive to pH, its vacuole formation was found only at pH 6.5. No vacuolization occurred in the cells of Nostoc sp. 96, Oscillatoria animlis 284 and Spirulina maxima 438 at all pH conditions we used. Vacuolization under unfavorable pH provides a new proof for the existence of vacuole in cells of cyanobacteria and reflects the prokaryote's function in ecological environment.

  3. Critical Factors Associated with Substance Abuse and Chemical Dependency in Nurse Anesthesia.

    Science.gov (United States)

    Norris, Jack; And Others

    1988-01-01

    Conducted survey to identify characteristics associated with chemical dependency among chemically dependent nurse anesthetists. Subjects were 21 nurse anesthetists who had been chemically dependent, had completed some form of drug treatment, and had been chemically free for at least one year. Investigated areas of employment setting, educational…

  4. All-Russia conference on chemical analysis of substances and materials. Abstracts of reports

    International Nuclear Information System (INIS)

    Collection contains abstracts of reports on chemical analysis of foods, drugs, environmental materials. Methods of chemical analysis used in such regions as chemical control in agriculture, criminology, art and archaeology, biotechnology, geology, chemistry and petrochemistry, metallurgy, metrology are presented. Theoretical, methodological and applied aspects of chemical analysis are considered

  5. Synthesis and characterization Bi2O2S thin film via chemical bath deposition at low pH.

    Science.gov (United States)

    Kariper, I Afşin

    2016-06-15

    Bismuth oxysulfide thin film was prepared using Bi(NO3)3 and Na2S as reactive. Since bismuth in the form of bismuth oxide is dissolved into water, bismuth and sulfide concentration of the chemical bath is very important. Bismuth oxysulfide (Bi2O2S) thin films were produced below pH2. Tested bismuth and sulfide concentrations are as follows: 2×10(-1)M, 2×10(-2)M, 2×10(-3)M, 2×10(-4)M bismuth and 1×10(-1)M, 1×10(-2)M, 1×10(-3)M, 1×10(-4)M sulfide. The structure of the films was examined via X-ray diffraction (XRD). Optical properties, such as transmission and absorbance were measured with Ultra violet-visible spectrum, and then refractive index and reflectivity were calculated. The pH of chemical bath was stabilized below pH of 2 using 13.85mL concentrated nitric acid. Deposition time and temperature of the baths were 4h and 30°C. It has been found that bismuth and sulfide concentrations affected the structure and thickness of the film. Also, optical band gap of the films varied with concentration, parallel to the change of the structure and film thickness. PMID:27043873

  6. ATSDR evaluation of health effects of chemicals. VI. Di(2-ethylhexyl)phthalate. Agency for Toxic Substances and Disease Registry.

    Science.gov (United States)

    Fay, M; Donohue, J M; De Rosa, C

    1999-12-01

    Di(2-ethylhexyl)phthalate (also known as DEHP, bis(2-ethylhexyl)phthalate, or BEHP; CAS Registry Number 117-81-7) is a widely-used plasticizer. It is found in numerous plastic articles, such as paints, inks, floor tiles, upholstery, shower curtains, footwear, plastic bags, food-packaging materials, toys, and medical tubing. Not surprisingly, DEHP appears at many waste sites. As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals that are of greatest public health concern at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priority List (NPL) sites. These profiles comprehensively summarize toxicological and environmental information. This article constitutes the release of the bulk of ATSDR's profile for DEHP (ATSDR, 1993) into the mainstream scientific literature. An extensive listing of human and animal health effects, organized by route, duration, and endpoint, is presented. Toxicological information on toxicokinetics, biomarkers, interactions, sensitive subpopulations, reducing toxicity after exposure, and relevance to public health is also included. Environmental information encompasses physical properties, production and use, environmental fate, levels seen in the environment, analytical methods, and a listing of regulations. ATSDR, at the behest of Congress and therefore the citizenry, prepares these profiles to inform the public about site contaminants. PMID:10786378

  7. Control of Chemical Risks by Substitution of Harmful Substances

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    1997-01-01

    Substitution of volatile, organic solvents with non-volatile, low-toxic esters of fatty acids for cleaning purposes in offset printing has successfully been implemented in several European countries. Similar substitutions in other industrial cleaning processes seem possible, especially regarding ...

  8. Effect of pH and chemical mechanical planarization process conditions on the copper–benzotriazole complex formation

    Science.gov (United States)

    Cho, Byoung-Jun; Kim, Jin-Yong; Hamada, Satomi; Shima, Shohei; Park, Jin-Goo

    2016-06-01

    Benzotriazole (BTA) has been used to protect copper (Cu) from corrosion during Cu chemical mechanical planarization (CMP) processes. However, an undesirable Cu–BTA complex is deposited after Cu CMP processes and it should be completely removed at post-Cu CMP cleaning for next fabrication process. Therefore, it is very important to understand of Cu–BTA complex formation behavior for its applications such as Cu CMP and post-Cu CMP cleaning. The present study investigated the effect of pH and polisher conditions on the formation of Cu–BTA complex layers using electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy) and the surface contact angle. The wettability was not a significant factor for the polishing interface, as no difference in the contact angles was observed for these processes. Both electrochemical techniques revealed that BTA had a unique advantage of long-term protection for Cu corrosion in an acidic condition (pH 3).

  9. 40 CFR 710.46 - Chemical substances for which information is not required.

    Science.gov (United States)

    2010-07-01

    ..., cellulose, gum), rubber, or lignin. (iii) This exclusion does not apply to a polymeric substance that has... 8052-42-4 Asphalt 61789-60-4 Pitch 63231-60-7 Paraffin waxes and hydrocarbon waxes, microcryst. 64741... Asphalt, oxidized 64742-94-5 Solvent naphtha (petroleum), heavy arom. 64742-95-6 Solvent...

  10. 77 FR 58665 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2012-09-21

    ... Register issue of April 24, 1990 (55 FR 17376) (April 24, 1990 SNUR). Consult that preamble for further... methods, periodic monitoring, respiratory protection, and recordkeeping. However, no comparable NCEL... states that the generic (non-confidential) use of the substances will be as pigment dispersants. Based...

  11. Combined effects of ionising gamma radiation and some chemical substances on the Allium sativum growth

    International Nuclear Information System (INIS)

    Co 60 - gamma ionising radiations act in different doses and flows on Allium sativum. They accelerate the germination of bulblets with a couple of days by comparison with the sample. The 10 Gy dose stimulates the plants growth. The 30 Gy dose or 'shock dose' related to the radiation flow and with chemicals used in the treatment, produces strong decays or raises of biological parameter values. The growth region which is implied in growing regulators synthesis is perturbed. The calculation of nuclear and cytoplasmic volumes of nucleus-cytoplasm ratio confirms the perturbation at this level. (Author)

  12. Restoration of radiation injury by ginseng, 2. Some properties of the radioprotective substances

    Energy Technology Data Exchange (ETDEWEB)

    Yonezawa, M.; Katoh, N.; Takeda, A. (Radiation Center of Osaka Prefecture, Sakai (Japan))

    1981-09-01

    Some properties of the radioprotective substances in a ginseng extract that increased the 30-day survival ratio in irradiated mice were studied. Methanol-soluble fraction of the extract did not protect the irradiated animals. Acid or alkali (0.12 N) inactivated the extract at 60/sup 0/C. But the radioprotective activity was stable after heating the ginseng extract in physiological saline at pH 7 in a boiling-water bath for 15 min. The ginseng extract was separated into two fractions by CM-cellulose column chromatography. One of them (CM-A) was significantly efficacious at 5% level, and the other (CM-B) at 0.1% level with the doses proportional to their yields. CM-B, not containing saponin, was subjected to further purification, UV spectrum and a biuret test suggested the presence of protein in this fraction. The supernatant obtained after heating CM-B solution at pH 7 was separated into three fractions, namely G-I, G-II and G-III, by gel-chromatography with a Sephadex G-75 column. Both G-I (0.44 mg per animal) and G-III (0.84 mg, calculated dose) were significantly efficacious, but G-II (0.47 mg) was not.

  13. Transcription of denitrification genes and kinetics of NO, N2O and N2 by soil bacteria as affected by pH

    Science.gov (United States)

    Liu, B.; Bakken, L. R.; Frostegard, A.

    2010-12-01

    Nitrous oxide (N2O), which is to a large part derived from denitrification in soil, is a major greenhouse gas and was also recently shown to be the single most important ozone-depleting substance. Previous studies demonstrate that the N2O/N2 product ratio of denitrification is strongly dependent on pH, increasing with decreasing soil pH. The mechanisms involved are, however, poorly understood. We here present an investigation of soils from a long-term liming experiment. Since it is difficult to control which pH is actually experienced by bacterial cells in intact soils, we extracted cells on a Nycodenz gradient and exposed them to different pH levels. Bacteria extracted from soils of 3 different pHs (4.0, 6.1 and 8.0) were incubated in minimal medium supplemented with nitrate (2mM) and glutamic acid (5 mM), buffered at three pH levels (5.7, 6.1 and 7.6). Both the pH of the medium and original soil pH showed profound effect on the denitrification activity in terms of gas emission kinetics. N2O reductase (N2OR) activity was only present when cells from the high pH soils (pH 6.1 and 8.0) were exposed to high pH medium (pH 7.6). Functional genes (nirS, nirK and nosZ) and their transcripts were quantified in the extracts from pH6.1-soil. A 10-25 fold higher expression of nosZ vs nirS was found when incubated at pH 7.6 compared to pH 6.1 and 5.7. The low but significant transcription of nosZ at pH 6.1 and 5.7 did not result in detectable N2O reduction however. Cells that had been allowed to assemble their proteome while growing in pH7 medium showed N2OR activity which was practically unaffected by pH within the range 5-7. On the contrary, no N2OR activity was detected if the proteome had been formed at pH 6. The cells extracted from acid soils (pH 5.8 and 6.1) showed very low nosZ transcritption and no N2OR activity if exposed to pH 7 during the transition from oxic to anoxic conditions, suggesting an adaptation to low pH in the sense that they do not transcribe the gene

  14. Bioremediation of toxic substances by mercury resistant marine bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    De, J.; Sarkar, A.; Ramaiah, N.

    Bioremediation of toxic substances includes microbe-mediated enzymatic transformation of toxicants to non-toxic, often assimilable, forms. Mercury-resistant marine bacteria are found to be very promising in dealing with mercury, and a host of other...

  15. A simultaneous determination of related substances by high performance liquid chromatography in a drug product using quality by design approach.

    Science.gov (United States)

    Tol, Trupti; Kadam, Nilesh; Raotole, Nilesh; Desai, Anita; Samanta, Gautam

    2016-02-01

    The combination of Abacavir, Lamivudine and Dolutegravir is an anti-retroviral formulation that displays high efficacy and superiority in comparison to other anti-retroviral combinations. Analysis of related substances in this combination drug product was very challenging due to the presence of nearly thirty peaks including the three active pharmaceutical ingredients (APIs), eleven known impurities and other pharmaceutical excipients. Objective of this study was to develop a single, selective, and robust high performance liquid chromatography method for the efficient separation of all peaks. Initially, one-factor-at-a-time (OFAT) approach was adopted to develop the method. But, it could not resolve all the critical peaks in such complex matrix. This led to the advent of two different HPLC methods for the determination of related substances, one for Abacavir and Lamivudine and the other for Dolutegravir. But, since analysis of a single sample using two methods instead of one is time and resource consuming and thus expensive, an attempt was made to develop a single and robust method by adopting quality by design (QbD) principles. Design of Experiments (DoE) was applied as a tool to achieve the optimum conditions through Response surface methodology with three method variables, pH, temperature, and mobile phase composition. As the study progressed, it was discovered that establishment of the design space was not viable due to the completely distant pH requirements of the two responses, i.e. (i) retention time for Lamivudine carboxylic acid and (ii) resolution between Abacavir impurity B and unknown impurity. Eventually, neglecting one of these two responses each time, two distinguished design spaces have been established and verified. Edge of failures at both design spaces indicate high probability of failure. It therefore, becomes very important to identify the most robust zone or normal operating range (NOR) within the design space with low risk of failure and high

  16. Prenatal Substance Exposure: What Predicts Behavioral Resilience by Early Adolescence?

    OpenAIRE

    Liebschutz, Jane; Crooks, Denise; Rose-Jacobs, Ruth; Cabral, Howard J.; Heeren, Timothy C.; Gerteis, Jessie; Appugliese, Danielle P.; Heymann, Orlaith D.; Lange, Allison V.; Frank, Deborah A.

    2015-01-01

    Understanding behavioral resilience among at-risk adolescents may guide public policy decisions and future programs. We examined factors predicting behavioral resilience following intrauterine substance exposure (IUSE) in a prospective longitudinal birth-cohort study of 136 early adolescents (age 12.4–15.9) at-risk for poor behavioral outcomes. We defined behavioral resilience as a composite measure of lack of early substance use initiation (before age 14), lack of risky sexual behavior, or l...

  17. Speeding chemical reactions by focusing

    Science.gov (United States)

    Lacasta, A. M.; Ramírez-Piscina, L.; Sancho, J. M.; Lindenberg, K.

    2013-04-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, and obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate ˜t-1/2 to very close to the perfect mixing rate, ˜t-1.

  18. Speeding chemical reactions by focusing

    CERN Document Server

    Lacasta, A M; Sancho, J M; Lindenberg, K

    2012-01-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  19. Use of computer-assisted prediction of toxic effects of chemical substances

    International Nuclear Information System (INIS)

    The current revision of the European policy for the evaluation of chemicals (REACH) has lead to a controversy with regard to the need of additional animal safety testing. To avoid increases in animal testing but also to save time and resources, alternative in silico or in vitro tests for the assessment of toxic effects of chemicals are advocated. The draft of the original document issued in 29th October 2003 by the European Commission foresees the use of alternative methods but does not give further specification on which methods should be used. Computer-assisted prediction models, so-called predictive tools, besides in vitro models, will likely play an essential role in the proposed repertoire of 'alternative methods'. The current discussion has urged the Advisory Committee of the German Toxicology Society to present its position on the use of predictive tools in toxicology. Acceptable prediction models already exist for those toxicological endpoints which are based on well-understood mechanism, such as mutagenicity and skin sensitization, whereas mechanistically more complex endpoints such as acute, chronic or organ toxicities currently cannot be satisfactorily predicted. A potential strategy to assess such complex toxicities will lie in their dissection into models for the different steps or pathways leading to the final endpoint. Integration of these models should result in a higher predictivity. Despite these limitations, computer-assisted prediction tools already today play a complementary role for the assessment of chemicals for which no data is available or for which toxicological testing is impractical due to the lack of availability of sufficient compounds for testing. Furthermore, predictive tools offer support in the screening and the subsequent prioritization of compound for further toxicological testing, as expected within the scope of the European REACH program. This program will also lead to the collection of high-quality data which will broaden the

  20. Determination of radium-226 in different substances without prior chemical separation

    International Nuclear Information System (INIS)

    A method is developed for the determination of radium-226, based on the measurement of the amount of radium-222, extracted from the substance being analyzed. The limit of detection of radium, equal to 6.6 X 10-15 mass%, is achieved because of the use of a low-background proportional counter and a special vacuum facility for filling the detector with the working gas mixture

  1. 77 FR 42990 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2012-07-23

    ..., tin zinc, calcium-doped (CAS No. 389623-01-2) and rutile, tin zinc, sodium-doped (CAS No. 389623-07-8... substances are identified as rutile, tin zinc, calcium-doped (PMN P-06-36; CAS No. 389623-01-2) and rutile... proposed rules for rutile, tin zinc, calcium-doped (PMN P-06-36; CAS No. 389623- 01-2) and rutile, tin...

  2. Regulation of the Glutamate-Glutamine Transport System by Intracellular pH in Streptococcus lactis

    NARCIS (Netherlands)

    POOLMAN, B; HELLINGWERF, KJ; KONINGS, WN

    1987-01-01

    Various methods of manipulation of the intracellular pH in Streptococcus lactis result in a unique relationship between the rate of glutamate and glutamine transport and the cytoplasmic pH. The initial rate of glutamate uptake by S. lactis cells increases more than 30-fold when the intracellular pH

  3. Calculation of Propulsive Nozzle Flowfields in Multidiffusing Chemically Reacting Environments. Ph.D. Thesis - Purdue Univ.

    Science.gov (United States)

    Kacynski, Kenneth John

    1994-01-01

    An advanced engineering model has been developed to aid in the analysis and design of hydrogen/oxygen chemical rocket engines. The complete multispecies, chemically reacting and multidiffusing Navier-Stokes equations are modelled, including the Soret thermal diffusion and the Dufour energy transfer terms. In addition to the spectrum of multispecies aspects developed, the model developed in this study is also conservative in axisymmetric flow for both inviscid and viscous flow environments and the boundary conditions employ a viscous, chemically reacting, reference plane characteristics method. Demonstration cases are presented for a 1030:1 area ratio nozzle, a 25 lbf film cooled nozzle, and a transpiration cooled plug and spool rocket engine. The results indicate that the thrust coefficient predictions of the 1030:1 and the 25 lbf film cooled nozzle are within 0.2 to 0.5 percent, respectively, of experimental measurements when all of the chemical reaction and diffusion terms are considered. Further, the model's predictions agree very well with the heat transfer measurements made in all of the nozzle test cases. The Soret thermal diffusion term is demonstrated to have a significant effect on the predicted mass fraction of hydrogen along the wall of the nozzle in both the laminar flow 1030:1 nozzle and the turbulent flow plug and spool nozzle analysis cases performed. Further, the Soret term was shown to represent an important fraction of the diffusion fluxes occurring in a transpiration cooled rocket engine.

  4. A novel process of dye wastewater treatment by linking advanced chemical oxidation with biological oxidation

    Directory of Open Access Journals (Sweden)

    Zou Haiming

    2015-12-01

    Full Text Available Dye wastewater is one of typically non-biodegradable industrial effluents. A new process linking Fenton’s oxidation with biological oxidation proposed in this study was investigated to degrade the organic substances from real dye wastewater. During the combination process, the Fenton’s oxidation process can reduce the organic load and enhance biodegradability of dye wastewater, which is followed by biological aerated filter (BAF system to further remove organic substances in terms of discharge requirement. The results showed that 97.6% of chemical oxygen demand (COD removal by the combination process was achieved at the optimum process parameters: pH of 3.5, H2O2 of 2.0 mL/L, Fe(II of 500 mg/L, 2.0 h treatment time in the Fenton’s oxidation process and hydraulic retention time (HRT of 5 h in the BAF system. Under these conditions, COD concentration of effluent was 72.6 mg/L whereas 3020 mg/L in the influent, thus meeting the requirement of treated dye wastewater discharge performed by Chinese government (less than 100 mg/L. These results obtained here suggest that the new process combining Fenton’s oxidation with biological oxidation may provide an economical and effective alternative for treatment of non-biodegradable industrial wastewater.

  5. Stimulation of granulocytic cell iodination by pine cone antitumor substances

    International Nuclear Information System (INIS)

    Antitumor substances (Fractions VI and VII) prepared from the NaOH extract of pine cone significantly stimulated the iodination (incorporation of radioactive iodine into an acid-insoluble fraction) of human peripheral blood adherent mononuclear cells, polymorphonuclear cells (PMN), and human promyelocytic leukemic HL-60 cells. In contrast, these fractions did not significantly increase the iodination of nonadherent mononuclear cells, red blood cells, other human leukemic cell lines (U-937, THP-1, K-562), human diploid fibroblast (UT20Lu), or mouse cell lines (L-929, J774.1). Iodination of HL-60 cells, which were induced to differentiate by treatment with either retinoic acid or tumor necrosis factor, were stimulated less than untreated cells. The stimulation of iodination of both PMN and HL-60 cells required the continuous presence of these fractions and was almost completely abolished by the presence of myeloperoxidase inhibitors. The stimulation activity of these fractions was generally higher than that of various other immunopotentiators. Possible mechanisms of extract stimulation of myeloperoxidase-containing cell iodination are discussed

  6. Method for the determination of an antigen or a hapten in a fluid sample by the use of a labelled substance

    International Nuclear Information System (INIS)

    The invention deals with a method for the determination of substances in a fluid sample that have a mutal specific binding affinity, such as antigens and antibodies. A column contains an insoluble, porous matrix with which specific binding partners to the substance to be determined are immobilized by chemical coupling to the matrix material. A predetermined quantity of a fluid sample containing the substance to be determined, and a reference sample containing a labelled form of the substance, together with an eluting liquid, is allowed to flow through the column. Followed by a determination of the relative amount of the labelled component retained in or eluted from the column, comparison to standard values affords a reading of the concentration or absolute amount of the substance to be determined in the fluid sample

  7. Comparison of the rationale used in setting occupational exposure standards for ionizing radiation and hazardous chemical substances

    International Nuclear Information System (INIS)

    Ten chemicals which create significant occupational hazard are reviewed. They are toluene diisocyanate, hydrogen fluoride, n-hexane, carbon disulphide, cadmium, inorganic mercury, cobalt, nitroglycerol, silica and vinyl chloride. Each is discussed under the headings of physiological intake and elimination in humans, characteristics of acute and chronic toxicity, sites of occupational exposure and rationale for limits of such exposure. Since radioactive substances yield ionizing radiation as the common hazard the treatment of the current permissible levels of exposure is somewhat simpler. Having set out industrial standards for exposure to hazardous substances and radionuclides, a detailed comparison is made. Exposure limits to ioninzing radiation are sufficiently low to remove the appearance of directly related injury. It is expected however that low level exposure may have a stochastic effect, that is, there is the possibility of a slightly increased incidence of neoplasms in a large exposed population, but numbers will be too small to be able to attribute any particular case to the exposure. TLVs on the other hand, depending on the particular chemical, may be high enough in the workplace to permit some directly related signs or symptoms in the exposed individual. 244 refs

  8. A rapid chemical method of labelling human plasma proteins with sup(99m)Tc-pertechnetate at pH 7.4

    International Nuclear Information System (INIS)

    A successful method for labelling human plasma proteins with sup(99m)Tc-pertechnetate by chemical means is described. The labelling methodology involves the production of Sup(99m)Tc-(Sn)citrate complex species with high protein binding capacity at pH 7.4 condition following initial chemical reduction of sodium sup(99m)Tc-pertechnetate by stannous chloride. A combined labelling efficiency range of 95-99% for sup(99m)Tc-labelled fibrinogen, immune gamma globulin and serum albumin is achieved. The actual amount of labelled protein content in the product is found to be 85-95% when assayed by ITLC and 74-85% by TCAA protein precipitation. In vitro experimental data indicate that sup(99m)Tc-fibrinogen contains an average of 85% clottable protein with an average clottability of 95%. This strongly suggests that the radioactive proteins retain much of their biological and physiological activities after the labelling process. (author)

  9. 78 FR 4446 - Exempt Chemical Preparations Under the Controlled Substances Act

    Science.gov (United States)

    2013-01-22

    ... and dependence and are controlled to protect the public health and safety. Section 201 of the CSA (21...... Flurazepam ....... Vial: 1 mL 12/22/2011 American Radiolabeled Chemicals, Inc... Heroin (1 mg/mL) Vial: 1 mL 12/22/2011 American Radiolabeled Chemicals, Inc... Heroin Vial: 1 mL 12/22/2011 American...

  10. 78 FR 66700 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2013-11-06

    ... FR 13708) (FRL-7335-2) (docket identification (ID) number EPA-HQ-OPPT-2005-0033). EPA received data... (76 FR 1067) (FRL-8846-9) (docket ID number EPA-HQ-OPPT-2007-0531). EPA received data on 5 chemicals...; Third Group of Chemicals,'' published in the Federal Register issue of October 21, 2011 (76 FR...

  11. Influence of alkaline (PH 8.3-12.0) and saline solutions on chemical, mineralogical and physical properties of two different bentonites - batch experiments at 25 deg. C

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Construction of a spent fuel repository deep in the bedrock will need supporting structures using cement materials. A part of them can be removed before closure but still it is estimated that about 1000 tonnes will remain in the host rock. Degradation of cementitious materials produces leachates of high pH. If such an alkaline plume reaches the bentonite buffer, it may induce mineralogical and chemical changes in bentonite over long term, and further affect the safety functions of the buffer. Laboratory experiments were done with the objective to gain data of possible alterations in mineralogical, chemical and physical properties of bentonites contacted with high-pH saline solutions. Two untreated, high grade, Na- and Ca-bentonites, were used in batch experiments, which were carried out in an anaerobic glove-box at 25±1 deg. C for 554 days. Each bentonite sample (20 g) was leached with approximately 3.8 L of leaching solution, which equals 190 mL/g of bentonite. The bentonites were leached with three types of simulated cement waters (pH 9.7, 11.3 and 12.0) and one saline groundwater simulate (pH 8.3) as a reference. The leaching solutions were 0.3 M, and contained NaCl and CaCl2, and trace amounts of SiO2, K, Br, Mg and SO4. Dissolved oxygen and carbon dioxide were removed from leaching solutions before mixing of bentonite in PC bottles. The samples were placed on a platform shaker in order to allow better contact between bentonite and the leaching solution. The evolution of pH in the samples was followed by measuring the pH-value of each sample in the solution phase approximately twice a week and the solution was renewed when values of two to three consecutive measurements did not change. On average, the leaching solution was renewed once a month. For each renewal of the leaching solution the phases were separated, the reacted solution withdrawn, and the chemical composition analysed. Before analysis the

  12. CRIM-TRACK: Sensor System for Detection of Criminal Chemical Substances

    DEFF Research Database (Denmark)

    Munk, Jens Kristian; Buus, Ole Thomsen; Larsen, Jan;

    2015-01-01

    drug-detecting scenario. Such decisions will be programmed to match user preference. Sensor output can be as detailed as the sensor allows. The user can be informed of the statistics behind the detection, identities of all detected substances, and quantities thereof. The response can also be simplified...... to “yes” vs. “no”. The technology under development in CRIM-TRACK will provide custom officers, police and other authorities with an effective tool to control trafficking of illegal drugs and drug precursors....

  13. CRIM-TRACK: Sensor System for Detection of Criminal Chemical Substances

    DEFF Research Database (Denmark)

    Munk, Jens Kristian; Buus, Ole Thomsen; Larsen, Jan;

    2015-01-01

    -detecting scenario. Such decisions will be programmed to match user preference. Sensor output can be as detailed as the sensor allows. The user can be informed of the statistics behind the detection, identities of all detected substances, and quantities thereof. The response can also be simplified to “yes” vs. “no......”. The technology under development in CRIM-TRACK will provide custom officers, police and other authorities with an effective tool to control trafficking of illegal drugs and drug precursors....

  14. Impact of soil pH and organic matter on the chemical bioavailability of vanadium species: The underlying basis for risk assessment.

    Science.gov (United States)

    Reijonen, Inka; Metzler, Martina; Hartikainen, Helinä

    2016-03-01

    The main objective of this study was to unravel the chemical reactions and processes dictating the potential bioavailability of vanadium (V). In environmental solutions V exists in two stable oxidation states, +IV and +V, of which + V is considered to be more toxic. In this study, the effect of speciation and soil pH on the chemical accessibility of V was investigated with two soils: 1) field soil rather rich in soil organic matter (SOM) and 2) coarse mineral soil low in SOM. Fresh soil samples treated with V(+V) (added as NaVO3) or V(+IV) (added as VOSO4) (pH adjusted to the range 4.0-6.9) were incubated for 3 months at 22 °C. The adsorption tendency of V species was explored by water extraction (Milli-Q water, 1:50 dw/V) and by sequential extraction (0.25 M KCl; 0.1 M KH2/K2HPO4; 0.1 M NaOH; 0.25 M H2SO4, 1:10 dw/V). The potential bioavailability of V was found to be dictated by soil properties. SOM reduced V(+V) to V(+IV) and acted as a sorbent for both species, which lowered the bioaccessibility of V. A high pH, in turn, favored the predominance of the V(+V) species and thus increased the chemical accessibility of V. PMID:26807983

  15. Separation and identification of moxifloxacin impurities in drug substance by high-performance liquid chromatography coupled with ultraviolet detection and Fourier transform ion cyclotron resonance mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Cai Sheng Wu; Zhi Xin Jia; Bao Ming Ning; Jin Lan Zhang; Song Wu

    2012-01-01

    In this paper,a high-performance liquid chromatography coupled with ultraviolet detection and Fourier transform-ion cyclotron resonance mass spectrometry (HPLC-UV/FTICRMS) method was described for the investigation of impurity profile in moxifloxacin (MOX) drug substance and chemical reference substance.Ten impurities were detected by HPLC-UV,while eight impurities were identified by using the high accurate molecular mass combined with multiple-stage mass spectrometric data and fragmentation rules.In addition,to our knowledge,five impurities were founded for the first time in MOX drug substance.

  16. Simultaneous determination by HPLC of 6 components in zedoary turmeric oil and its related injections with replacement method of chemical reference substance%HPLC替代对照品法同时测定莪术油及其注射液中6种成分的含量

    Institute of Scientific and Technical Information of China (English)

    何欢; 马双成; 张启明; 田颂九

    2009-01-01

    Objective:To establish and validate an HPLC method with single marker to simultaneously determine six components in zedoary turmeric oil and its related injections.Methods:The relative correction factors(RCF)of the five components(curdione,curcumol,curzerene,furanodiene,β-elemene)were measured by HPLC under different conditions with germacrone as standard reference.Assay of zedoary turmeric oil and its related injections was determined by replacement method of chemical reference substance and the conventional HPLC method with the above SIX components as the index components.The analysis was performed on a Waters Symmetry C_(18)(4.6 mm×250 mm,5 m)column;The mobile phase was composed of methanol-water with a linear gradient elution:The flow rate Was 1.0 mL·min~(-1) and the temperature of colulun was 30 ℃;The UV detection wavelength was set at 215 nm.Results:The quantitative results of the new method were almost consistent with the results of conventional HPLC method.Conclusion:For the first time,the replacement method of chemical reference substance is adopted in HPLC simultaneous determination of zedoary turmeric oil and its related injections.The new method is economical and practical which is highly effective and accurate for quality control of zedoary turmeric oil and its related injections.%目的:建立HPLC替代对照品法同时测定莪术油及其注射液中6种成分含量.方法:本文采用HPLC方法,在不同条件下测定(牛龙)牛儿酮与其他5种成分(莪术二酮、莪术醇、莪术烯、呋喃二烯及β-榄香烯)间的相对校正因子(RCF).以上述6种成分为指标,分别利用替代对照品法和常规含量测定方法对莪术油及其注射液进行含量测定.色谱条件:采用Waters Symmetry C_(18)(4.6 mm×250 mm,5 μm)色谱柱,流动相为甲醇-水,梯度洗脱,流速1.0 mL·min~(-1),柱温30℃,检测波长215 nm.结果:以替代对照品法测得的结果与常规含量测定方法结果一致.结论:本试验在

  17. Capturing intracellular pH dynamics by coupling its molecular mechanisms within a fully tractable mathematical model.

    Directory of Open Access Journals (Sweden)

    Yann Bouret

    Full Text Available We describe the construction of a fully tractable mathematical model for intracellular pH. This work is based on coupling the kinetic equations depicting the molecular mechanisms for pumps, transporters and chemical reactions, which determine this parameter in eukaryotic cells. Thus, our system also calculates the membrane potential and the cytosolic ionic composition. Such a model required the development of a novel algebraic method that couples differential equations for slow relaxation processes to steady-state equations for fast chemical reactions. Compared to classical heuristic approaches based on fitted curves and ad hoc constants, this yields significant improvements. This model is mathematically self-consistent and allows for the first time to establish analytical solutions for steady-state pH and a reduced differential equation for pH regulation. Because of its modular structure, it can integrate any additional mechanism that will directly or indirectly affect pH. In addition, it provides mathematical clarifications for widely observed biological phenomena such as overshooting in regulatory loops. Finally, instead of including a limited set of experimental results to fit our model, we show examples of numerical calculations that are extremely consistent with the wide body of intracellular pH experimental measurements gathered by different groups in many different cellular systems.

  18. Accelerated tests of hardened cement pastes alteration by organic acids: analysis of the pH effect

    International Nuclear Information System (INIS)

    Effluents, such as liquid manure and silage effluents, stored in silos often made of concrete, contain organic acids that are chemically very aggressive for the cement-based matrix. The pH of liquid manure is comprised between 6 and 8, and the pH of silage effluent is about 4. There has already been much research done on manure's effect on concrete using aggressive solutions with a pH of or inferior to 4, in order to accelerate alteration kinetics. These studies aimed at simulating liquid manure and silage effluent, equally. The goal of this article is to validate the use of solutions with a pH of 4 to implement accelerated studies on alterations occurring to structures exposed to the acidic part of liquid manure. In this study, the alteration mechanisms of the cement-based matrix produced by two solutions of organic acids with pH of 4 and 6 were compared. At the end of the experiment, carried out on ordinary Portland cement and slag cement pastes, the kinetics of alteration of the cement pastes immersed in the solution with a pH of 4 was ninefold higher than in the solution with a pH of 6. The chemical and mineralogical modifications of the paste were analyzed by electron microprobe, XRD and BSE mode observations. It was shown that the alteration mechanisms of the paste are sensibly identical for both solutions: almost complete decalcification, the disappearance of the crystallized or amorphous hydrated phases and the probable formation of a silica gel containing aluminum and iron, mainly. The differences in alteration mechanisms between the two solutions are minor and mainly concern the stability of the anhydrous phases: C4AF and slag grains

  19. Bullying Victimization and Substance Use Among U.S. Adolescents: Mediation by Depression

    OpenAIRE

    Luk, Jeremy W.; Jing WANG; Simons-Morton, Bruce G.

    2010-01-01

    This study examined the link between bullying victimization and substance use and tested the mediating role of depression in male and female adolescents. Cross-sectional data were collected from a national sample of 1,495 tenth graders who participated in the 2005/06 Health Behaviors in School-aged Children U.S. Survey. Victimization, depression and substance use were all measured as latent variables. Substance use was measured by drinking alcohol, being drunk, smoking cigarettes and using ma...

  20. Substance P Depolarizes Lamprey Spinal Cord Neurons by Inhibiting Background Potassium Channels

    OpenAIRE

    Thörn Pérez, Carolina; Hill, Russell H.; Grillner, Sten

    2015-01-01

    Substance P is endogenously released in the adult lamprey spinal cord and accelerates the burst frequency of fictive locomotion. This is achieved by multiple effects on interneurons and motoneurons, including an attenuation of calcium currents, potentiation of NMDA currents and reduction of the reciprocal inhibition. While substance P also depolarizes spinal cord neurons, the underlying mechanism has not been resolved. Here we show that effects of substance P on background K+ channels are the...

  1. Characterisation of inhibitory substances produced by two Pseudoalteromonas species and the cyanobacterial strain Flo1

    OpenAIRE

    Rau, Jan Erik

    2011-01-01

    In the present study the inhibitory substances of P. aurantia NCIMB 2052T and P. citrea NCIMB 1889T were investigated with respect to their substantial and functional nature, their inhibitory potential, their stability against various treatments as well as the growth phases and incubation conditions when the substances are produced. In addition, an inhibitory substance produced by strain Flo1 was examined regarding its structure, function, and inhibitory potential. Furthermore, its taxonomic ...

  2. Six rapid assessments of alcohol and other substance use in populations displaced by conflict

    OpenAIRE

    Adelekan Moruf; Macdonald David; Schilperoord Marian; Burton Ann; Oppenheimer Edna; Ezard Nadine; Sakarati Abandokoth; van Ommeren Mark

    2011-01-01

    Abstract Background Substance use among populations displaced by conflict is a neglected area of public health. Alcohol, khat, benzodiazepine, opiate, and other substance use have been documented among a range of displaced populations, with wide-reaching health and social impacts. Changing agendas in humanitarian response-including increased prominence of mental health and chronic illness-have so far failed to be translated into meaningful interventions for substance use. Methods Studies were...

  3. Management of sites potentially polluted by radioactive substances - Methodological guidebook

    International Nuclear Information System (INIS)

    This document is the update of the 'methodological guidelines for the management of industrial areas potentially contaminated by radioactive substances', published in 2001 by IRSN. Revisions intended to bring coherence between management of areas polluted by radioactive substances and the general policy applied to polluted sites described in a document published in February 2007 by the French Ministry in charge of Environment. Requirements introduced both by the law relative to waste management of June 28, 2006 and the ministerial order of 17 November 2008 were introduced. The involvement of all stakeholders during the process was stressed. The updating, mainly lead to introduce a clear distinction between polluted areas where uses are established and those without use or at redevelopment stage. When the uses are established, an 'Interpretation of the condition of environment' is conducted. Alternatively, the remediation process follows a 'management plan'. The revision also led to the disappearance of the 'doubt removal' phase which has been incorporated as an entire part in the site characterisation. Among other significant changes, it may be noted the evolution of the 'risk assessment' tools from simplified risk assessment and detailed risk assessment to a single tool allowing the quantitative assessment of exposure (EQER). Finally, the guidelines highlight stakeholder involvement in identifying the different participants and in reminding the benefits of a consultative approach. Whatever the remediation process: interpretation of the condition of environment or management plan; site characterisation is required as soon as a pollution is suspected. It includes literature reviews and field investigations primarily to confirm or deny the presence of pollution and, where appropriate, to determine its location, nature and level. The effort accorded to site characterisation must be proportionate to identified issues. The first step consists in comparing the

  4. Apparent formation constants of actinide complexes with humic substances determined by solvent extraction

    International Nuclear Information System (INIS)

    Apparent formation constants of Pu(IV) with two kinds of humic substances (HSs) were determined in 0.1M NaClO4 at 25°C using a back-solvent extraction method. The effect of solution conditions, such as the pH, the initial metal and HS concentrations, and the ionic strength, on the formation constants was investigated. The obtained data were compared with the other actinide series. (author)

  5. Simulation of dye adsorption by beech sawdust as affected by pH.

    Science.gov (United States)

    Batzias, F A; Sidiras, D K

    2007-03-22

    The effect of pH on the batch kinetics of methylene blue adsorption on beech sawdust was simulated, in order to evaluate sawdust potential use as low cost adsorbent for wastewater dye removal. The zero point of charge pH(pzc) of the sawdust, in order to explain the effect of pH in terms of pH(pzc), was measured by the mass titration and the automatic titration methods. The adsorption capacity, estimated according to Freundlich's model, indicate that increase of the pH enhances the adsorption behaviour of the examined material. The lower adsorption of methylene blue at acidic pH is due to the presence of excess H(+) ions that compete with the dye cation for adsorption sites. As the pH of the system increases, the number of positively charged sites decreases while the number of the negatively charged sites increases. The negatively charged sites favour the adsorption of dye cation due to electrostatic attraction. The increase in initial pH from 8.0 to 11.5 increases the amount of dye adsorbed. PMID:16934396

  6. History of the occupational exposure to chemical substances in workers with laryngeal cancer

    International Nuclear Information System (INIS)

    A case-control study was realized to 400 patients, 200 of them histologically confirmed as incident cases of larynx cancer by the National Institute for Oncology and Radiobiology of Havana, and the others 200 as controls, coming from another hospitals. A survey was applied to both groups, collecting every theirs worker histories with emphasis on occupational exposure, that were codified by an expert group taking into account the carcinogens present according to the guided code of the Epidemiological Units of Environmental Cancer and the Fields Studies and Intervention of International Agency for Research on Cancer (IARC). According to the results obtained, all the patients, cases and controls, presented 1 526 tasks in their labour histories, that represented an average greater than 3 tasks for each one of them. They main activities were in the agriculture, the defence and the sugar cane industry. The most predominant exposures were to the abrasive dusts, motor emissions, mists of mineral oils, gasoline/petroleum/diesel/kerosene and pesticides. In general, the valuation of the chemical risk was considered of low intensity, 1-5% of the real time to the exposure and all had the certain probability of the agent's aggressor presence.

  7. 78 FR 49547 - Manufacturer of Controlled Substances; Notice of Registration; American Radiolabeled Chemicals, Inc.

    Science.gov (United States)

    2013-08-14

    ..., 2013, 78 FR 23596, American Radiolabeled Chemicals, Inc., 101 Arc Drive, St. Louis, Missouri 63146... Dimethyltryptamine (7435) I 1- piperidine I (7470). Dihydromorphine (9145) I Heroin (9200) I Normorphine (9313)...

  8. CRIM-TRACK: sensor system for detection of criminal chemical substances

    Science.gov (United States)

    Munk, Jens K.; Buus, Ole T.; Larsen, Jan; Dossi, Eleftheria; Tatlow, Sol; Lässig, Lina; Sandström, Lars; Jakobsen, Mogens H.

    2015-10-01

    Detection of illegal compounds requires a reliable, selective and sensitive detection device. The successful device features automated target acquisition, identification and signal processing. It is portable, fast, user friendly, sensitive, specific, and cost efficient. LEAs are in need of such technology. CRIM-TRACK is developing a sensing device based on these requirements. We engage highly skilled specialists from research institutions, industry, SMEs and LEAs and rely on a team of end users to benefit maximally from our prototypes. Currently we can detect minute quantities of drugs, explosives and precursors thereof in laboratory settings. Using colorimetric technology we have developed prototypes that employ disposable sensing chips. Ease of operation and intuitive sensor response are highly prioritized features that we implement as we gather data to feed into machine learning. With machine learning our ability to detect threat compounds amidst harmless substances improves. Different end users prefer their equipment optimized for their specific field. In an explosives-detecting scenario, the end user may prefer false positives over false negatives, while the opposite may be true in a drug-detecting scenario. Such decisions will be programmed to match user preference. Sensor output can be as detailed as the sensor allows. The user can be informed of the statistics behind the detection, identities of all detected substances, and quantities thereof. The response can also be simplified to "yes" vs. "no". The technology under development in CRIM-TRACK will provide custom officers, police and other authorities with an effective tool to control trafficking of illegal drugs and drug precursors.

  9. A Survey of Substance Use for Cognitive Enhancement by University Students in the Netherlands

    Directory of Open Access Journals (Sweden)

    Kimberly Johanna Schelle

    2015-02-01

    Full Text Available Background:Pharmacological cognitive enhancement, using chemicals to change cellular processes in the brain in order to enhance one’s cognitive capacities, is an often discussed phenomenon. The prevalence among Dutch university students is unknown.Methods:The study set out to achieve the following goals: (1 give an overview of different methods in order to assess the prevalence of use of prescription, illicit and lifestyle drugs for cognitive enhancement (2 investigate whether polydrug use and stress have a relationship with cognitive enhancement substance use (3 assessing opinions about cognitive enhancement prescription drug use. A nationwide survey was conducted among 1572 student respondents of all government supported Dutch universities. Results:The most detailed level of analysis ─ use of specific substances without a prescription and with the intention of cognitive enhancement ─ shows that prescription drugs, illicit drugs and lifestyle drugs are respectively used by 1.7%, 1.3% and 45.6% of the sample. The use of prescription drugs and illicit drugs is low compared to other countries. We have found evidence of polydrug use in relation to cognitive enhancement. A relation between stress and the use of lifestyle drugs for cognitive enhancement was observed. We report the findings of several operationalizations of cognitive enhancement drug use to enable comparison with a wider variety of previous and upcoming research.Conclusions:Results of this first study among university students in the Netherlands revealed a low prevalence of cognitive enhancement drug use compared to other countries. Multiple explanations, such as a difference in awareness of pharmacological cognitive enhancement among students, accessibility of drugs in the student population and inclusion criteria of enhancement substances are discussed. We urge enhancement researchers to take the different operationalizations and their effects on the prevalence numbers into

  10. Administrative regulations concerning the carriage of dangerous substances by civil aircraft

    International Nuclear Information System (INIS)

    The Regulations, which entered into force on the date they were adopted, apply to the transport of dangerous substances by civil aircraft in Norway and by aircraft registered in Norway for transport outside Norwegian territory. They provide that such substances, including radioactive materials, must be carried in accordance with the IATA Restricted Articles Regulations

  11. Identification of Low-Molecular-Weight Nucleic Acid-Related Substances Secreted by Streptomyces aureofaciens

    OpenAIRE

    De Carvalho, Alírio; Molinari, Rubens

    1983-01-01

    Streptomyces aureofaciens growth in chemically defined medium is actively associated with the secretion of low-molecular-weight nucleic acid-related substances and is linked to low availability of phosphate. Thirteen pure compounds were isolated, of which seven were identified.

  12. Structural Plasticity of Staphylococcal Nuclease Probed by Perturbation with Pressure and pH

    Science.gov (United States)

    Kitahara, Ryo; Hata, Kazumi; Maeno, Akihiro; Akasaka, Kazuyuki; Chimenti, Michael; Bertrand Garcia-Moreno, E; Schroer, Martin A.; Jeworrek, Christoph; Tolan, Metin; Winter, Roland; Roche, Julien; Roumestand, Christian; de Guillen, Karine Montet; Royer, Catherine A.

    2012-01-01

    The ionization of internal groups in proteins can trigger conformational change. Despite this being the structural basis of most biological energy transduction, these processes are poorly understood. SAXS and NMR spectroscopy experiments at ambient and high hydrostatic pressure were used to examine how the presence and ionization of Lys-66, buried in the hydrophobic core of a stabilized variant of staphylococcal nuclease, affect conformation and dynamics. NMR spectroscopy at atmospheric pressure showed previously that the neutral Lys-66 affects slow conformational fluctuations globally, whereas the effects of the charged form are localized to the region immediately surrounding position 66. Ab initio models from SAXS data suggest that when Lys-66 is charged the protein expands, which is consistent with results from NMR spectroscopy. The application of moderate pressure (< 2 kbar) at pH values where Lys-66 is normally neutral at ambient pressure left most of the structure unperturbed but produced significant non-linear changes in chemical shifts in the helix where Lys-66 is located. Above 2 kbar pressure at these pH values the protein with Lys-66 unfolded cooperatively adopting a relatively compact, albeit random structure according to Kratky analysis of the SAXS data. In contrast, at low pH and high pressure the unfolded state of the variant with Lys-66 is more expanded than that of the reference protein. The combined global and local view of the structural reorganization triggered by ionization of the internal Lys-66 reveals more detectable changes than were previously suggested by NMR spectroscopy at ambient pressure. PMID:21254234

  13. Removal of humic substances from water by brown coal sorbents

    Energy Technology Data Exchange (ETDEWEB)

    E.V. Veprikova; A.V. Rudkovskii; M.L. Shchipko [Russian Academy of Sciences, Krasnoyarsk (Russian Federation). Institute of Chemistry and Chemical Technology, Siberian Branch

    2007-12-15

    Brown coal sorption materials with high activity toward humic substances were prepared using a larger scale laboratory unit with a spouted-bed system. The effect of thermal treatment conditions on the sorption properties of these materials was studied. It was found that the sorption activity of the resulting samples toward humates was closely related to the limiting sorption volume of the materials with respect to benzene.

  14. Regularities of development of unspecific reaction of cells, and modification of chemical protection

    International Nuclear Information System (INIS)

    Regularities of development of a unspecific reaction of cells under the effect of different substances belonging to weak electrolytes have been studied. It was demonstrated that the rate of the unspecific reaction development under the effect of cysteamine and caffeine-benzoate depends on the agent concentration, temperature and pH of a medium. It was established that the response of a cell is determined by the overall intracellular concentration of the agent rather than by its specific character. The total concentration of the substance inside the cell depends on its physico-chemical characteristics and, with a pH gradient between cell and medium, can markedly vary from that in the medium. With similar intracellular content, both substances proved to be virtually equally effective. This suggests that it is possible to assess the effectiveness of some other biologically active substances many of which are weak electrolytes

  15. 77 FR 25235 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2012-04-27

    ...'s first direct final SNUR published in the Federal Register issue of April 24, 1990 (55 FR 17376... described in the New Chemicals Program's PBT category (64 FR 60194, November 4, 1999) (FRL-6097-7). EPA... alkenylsuccinate, ethanolamine salt (generic). CAS numbers: Not available. Basis for action: The consolidated...

  16. Substance P receptor binding sites are expressed by glia in vivo after neuronal injury

    International Nuclear Information System (INIS)

    In vitro studies have demonstrated that glia can express functional receptors for a variety of neurotransmitters. To determine whether similar neurotransmitter receptors are also expressed by glia in vivo, the authors examined the glial scar in the transected optic nerve of the albino rabbit by quantitative receptor autoradiography. Receptor binding sites for radiolabeled calcitonin gene-related peptide, cholecystokinin, galanin, glutamate, somatostatin, substance P, and vasoactive intestinal peptide were examined. Specific receptor binding sites for each of these neurotransmitters were identified in the rabbit forebrain but were not detected in the normal optic nerve or tract. In the transected optic nerve and tract, only receptor binding sites for substance P were expressed at detectable levels. The density of substance P receptor binding sites observed in this glial scar is among the highest observed in the rabbit forebrain. Ligand displacement and saturation experiments indicate that the substance P receptor binding site expressed by the glial scar has pharmacological characteristics similar to those of substance P receptors in the rabbit striatum, rat brain, and rat and canine gut. The present study demonstrates that glial cells in vivo express high concentrations of substance P receptor binding sites after transection of retinal ganglion cell axons. Because substance P has been shown to regulate inflammatory and immune responses in peripheral tissues, substance P may also, by analogy, be involved in regulating the glial response to injury in the central nervous system

  17. Brief Report: Pregnant by Age 15 Years and Substance Use Initiation among US Adolescent Girls

    Science.gov (United States)

    Cavazos-Rehg, Patricia A.; Krauss, Melissa J.; Spitznagel, Edward L.; Schootman, Mario; Cottler, Linda B.; Bierut, Laura Jean

    2012-01-01

    We examined substance use onset and associations with pregnancy by age 15 years. Participants were girls ages 15 years or younger (weighted n = 8319) from the 1999-2003 Youth Risk Behavior Surveillance System (YRBS). Multivariable logistic regression examined pregnancy as a function of substance use onset (i.e., age 10 years or younger, 11-12,…

  18. Study of isotopic tracing related with mechanism of cancer caused by carcinogenic substance

    International Nuclear Information System (INIS)

    In order to understand the mechanism of cancer caused by carcinogenic substance, a project using 41Ca as tracer and accelerator mass spectrometry (AMS) as measurement method to investigate the origin of the increased Ca2+ when the cells are exposed to carcinogenic substances is being undertaken. Several results as bellow have been obtained

  19. Effect of humic substances on the precipitation of calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    SONG Yong-hui; Hermann H. HAHN; Erhard HOFFMANN; Peter G. WEIDLER

    2006-01-01

    For phosphorus (P) recovery from wastewater, the effect of humic substances (HS) on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate (as P) and 20 mg/L HS (as dissolved organic carbon, DOC) at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium (Ca) and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction (XRD) and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0,the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤ 3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite (HAP) by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.

  20. Chemical espionage by parasitic wasps. How Trichogramma species exploit moth sex pheromone systems.

    NARCIS (Netherlands)

    Noldus, L.P.J.J.

    1989-01-01

    Interactions between insects are for a great deal mediated by semiochemicals. For instance, female moths release specific volatile chemicals in order to attract males of the same species. These substances are called sex pheromones. Egg parasitoids use various chemical cues in their search for hosts,

  1. [Neurotoxicity of chemical substances in the workplace. VI. Longitudinal study of persons occupationally exposed to mercury].

    Science.gov (United States)

    Triebig, G; Grobe, T; Saure, E; Schaller, K H; Weltle, D; Valentin, H

    1984-01-01

    A longitudinal study was performed on eleven persons, who had been chronically exposed to mercury (Hg) (3 to 31 years, median 5 years) in 1977, 1980 resp., and 1982. During their work in a chemical plant they had had contact to elemental Hg and various inorganic as well as organic mercury compounds. The main purpose of the investigation was the evaluation of possible adverse effects to the nervous system caused by mercury. The internal Hg-exposure was measured by mercury analysis in blood (Hg-B) and in urine (Hg-U). Furthermore "time-weighted average" levels were calculated on the basis of former Hg-determinations from 1974 to 1982. For Hg-B these values ranged between 26 and 104 microgram/dl (median 42 microgram/l) and for Hg-U between 73 and 434 microgram/g creatinine (median 233 microgram/g creatinine) (upper normal levels: Hg-B: 5 microgram/l; Hg-U: 5 microgram/g creatinine). The determination of the peripheral nerve conduction velocities (NLG) of motor and sensory fibers as well as the registration of somatosensory-evoked potentials (SEP) revealed no pathological results, except one borderline case. The NLG- and SEP-values did not significantly differ from those of non exposed persons or from those of former NLG-determinations. No correlations were found between indicators of Hg-exposure and neurophysiological parameters regarding dose-effect-relationship. Statistical differences resulted in the time-dependent test of the psychological test battery performed in comparison to age-matched control persons of equal socio-economous status. In additional, significant relationships were calculated between Hg-exposure and these tests. Considering the inter- and intraindividual variations of the psychological test results, there were no substantial alterations in the total findings over the observed period except for one case. Workers with Hg-exposure below the current BAT-values (Hg-B 50 microgram/l, Hg-U 200 microgram/l) showed no pathological findings in the

  2. Dual-Responsive Lipid Nanotubes: Two-Way Morphology Control by pH and Redox Effects.

    Science.gov (United States)

    Unsal, Hande; Schmidt, Judith; Talmon, Yeshayahu; Yildirim, Leyla Tatar; Aydogan, Nihal

    2016-05-31

    Lipid nanotubes are the preferred structures for many applications, especially biological ones, and thus have attracted much interest recently. However, there is still a significant need for developing more lipid nanotubes that are reversibly controllable to improve their functionality and usability. Here, we presented a two-way reversible morphology control of the nanotubes formed by the recently designed molecule AQUA (C25H29NO4). Because of its special design, the AQUA has both pH-sensitive and redox-active characters provided by the carboxylic acid and anthraquinone groups. Upon chemical reduction, the nanotubes turned into thinner ribbons, and this structural transformation was significantly reversible. The reduction of the AQUA nanotubes also switched the nanotubes from electrically conductive to insulative. Nanotube morphology can additionally be altered by decreasing the pH below the pKa value of the AQUA, at ∼4.9. Decreasing the pH caused the gradual unfolding of the nanotubes, and the interlayer distance in the nanotube's walls increased. This morphological change was fast and reversible at a wide pH range, including the physiological pH. Thus, the molecular design of the AQUA allowed for an unprecedented two-way and reversible morphology control with both redox and pH effects. These unique features make AQUA a very promising candidate for many applications, ranging from electronics to controlled drug delivery. PMID:27148756

  3. Fouling of enhanced biological phosphorus removal-membrane bioreactors by humic-like substances.

    Science.gov (United States)

    Poorasgari, Eskandar; König, Katja; Fojan, Peter; Keiding, Kristian; Christensen, Morten Lykkegaard

    2014-12-01

    Fouling by free extracellular polymeric substances was studied in an enhanced biological phosphorus removal-membrane bioreactor. It was demonstrated that the free extracellular polymeric substances, primarily consisting of humic-like substances, were adsorbed to the membrane used in the enhanced biological phosphorus removal-membrane bioreactor plant. Infrared analyses indicated the presence of the humic-like substances on the membrane's active surface after filtration of the free extracellular polymeric substances suspension. Scanning electron microscopy showed the presence of a gel layer on the membrane surface after filtration of the free extracellular polymeric substances suspension. The gel layer caused a significant decline in water flux. This layer was not entirely removed by a backwashing, and the membrane's water flux could not be re-established. The membrane used in the enhanced biological phosphorus removal-membrane bioreactor plant showed infrared spectra similar to that fouled by the free extracellular polymeric substances suspension in the laboratory. Thus, the results of this study show the importance of humic-like substances in irreversible fouling of enhanced biological phosphorus removal-membrane bioreactor systems. PMID:25014564

  4. Characterization of Combinatorial Effects of Toxic Substances by Cell Cultivation in Micro Segmented Flow

    Science.gov (United States)

    Cao, J.; Kürsten, D.; Funfak, A.; Schneider, S.; Köhler, J. M.

    This chapter reviews the application of micro segmented flow for the screening of toxic effects on bacteria, eukaryotic microorganisms, human cells and multicellular systems. Besides, the determination of complete dose/response functions of toxic substances with a minimum of cells and chemicals, it is reviewed how two- and multi-dimensional concentration spaces can be screened in order to evaluate combinatorial effects of chemicals on cells. The challenge for the development of new and miniaturized methods is derived from the increase of the number of different used substances in technique, agriculture and medicine, from the increasing release of new substances and nanomaterials into our environment and from the improvement of the insight of toxicity of natural substances and the interferences between different substances resulting in toxic effects on different organisms, cells and tissues. The application of two-dimensional toxicological screenings on selected examples of effector combinations is described. Examples for the detection of an independent, an additive and a synergistic interference between two substances are given. In addition, it is shown that the screening for toxicological effects in complete two-dimensional concentration spaces allows the detection of complex response behaviour—for example, the formation of tolerances and stimulation peaks—which thereby can be characterized. The characterization of interference of toxic organic substances with silver nanoparticles is reported as an example for the potential of micro segmented-flow technique for evaluating the toxicological impact of new materials. Finally, it is demonstrated that the technique can be applied for different organisms like simple bacteria, single cell alga such as Chlorella vulgaris and multicellular systems up to the development of complete organisms beginning from eggs.

  5. Effect of pH on Cleavage of Glycogen by Vaginal Enzymes.

    Science.gov (United States)

    Spear, Greg T; McKenna, Mary; Landay, Alan L; Makinde, Hadijat; Hamaker, Bruce; French, Audrey L; Lee, Byung-Hoo

    2015-01-01

    Glycogen expressed by the lower genital tract epithelium is believed to support Lactobacillus growth in vivo, although most genital isolates of Lactobacillus are not able to use glycogen as an energy source in vitro. We recently reported that α-amylase is present in the genital fluid of women and that it breaks down glycogen into small carbohydrates that support growth of lactobacilli. Since the pH of the lower genital tract can be very low, we determined how low pH affects glycogen processing by α-amylase. α-amylase in saliva degraded glycogen similarly at pH 6 and 7, but activity was reduced by 52% at pH 4. The glycogen degrading activity in nine genital samples from seven women showed a similar profile with an average reduction of more than 50% at pH 4. However, two samples collected from one woman at different times had a strikingly different pH profile with increased glycogen degradation at pH 4, 5 and 6 compared to pH 7. This second pH profile did not correlate with levels of human α-acid glucosidase or human intestinal maltase glucoamylase. High-performance anion-exchange chromatography showed that mostly maltose was produced from glycogen by samples with the second pH profile in contrast to genital α-amylase that yielded maltose, maltotriose and maltotetraose. These studies show that at low pH, α-amylase activity is reduced to low but detectable levels, which we speculate helps maintain Lactobacillus growth at a limited but sustained rate. Additionally, some women have a genital enzyme distinct from α-amylase with higher activity at low pH. Further studies are needed to determine the identity and distribution of this second enzyme, and whether its presence influences the makeup of genital microbiota. PMID:26171967

  6. ENHANCING THE ECONOMIC LIABILITY OF BIOREFINERIES BY TRANSFORMING LIGNIN FROM LIGNOCELLULOSIC BIOMASSES INTO HUMIC-LIKE SUBSTANCES WITH PLANT PROMOTING BIOACTIVITY

    OpenAIRE

    Savy, Davide

    2013-01-01

    In this study, lignin from three biomasses (miscanthus, giant reed and a pre-treated giant reed) has been isolated by two different methodologies and thoroughly characterized to produce humic-like substances, which were shown to positively affect plant growth and physiology. The techniques employed concerned the use of either sulfuric acid (SAL) or hydrogen peroxide at alkaline pH (Ox). Low yields were obtained by the Ox-method (less than 30% of Klason lignin), whereas the amount of materials...

  7. Science and Engineering Ph.D. Students' Career Outcomes, by Gender.

    Directory of Open Access Journals (Sweden)

    Annamaria Conti

    Full Text Available We examine differences in the careers of men and women Ph.D.s from two major European universities. Having performed regression analysis, we find that women are more likely than men to be employed in public administration when the alternatives are either academia or industry. Between the latter two alternatives, women are more likely to be employed in academia. These gender differences persist after accounting for Ph.D.s' and their supervisors' characteristics. Gender gaps are smaller for Ph.D.s with large research outputs and for those who conducted applied research. Restricting the analysis to Ph.D.s who pursued postdoc training, women are less likely than men to be employed in highly ranked universities, even after controlling for their research outputs. Finally, we find gender differences in Ph.D.s' appointment to professorship, which are explained by the Ph.D.s' publication output and the quality of their postdoc training.

  8. Research and Discussion on Physical and Chemical Properties of Cultivating Substrate with Facilities

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This article, by comparing the basic concepts of substrate and soil, their composition of substance and methods of measuring the indexes of physical and chemical properties, analyzes and researches ways of choosing substrate for cultivation with facilities. It indicates that the normal physical and chemical indexes of evaluating a substrate are bulk density, total porosity, non-capillary porosity, ratio of big porosity to small porosity, the pH and the electrical conductivity (EC) value of the substrate. By...

  9. Effect of pH on paste properties of irradiated corn starch by gamma-rays

    International Nuclear Information System (INIS)

    The degradation of starch by γ-irradiation and the effect of pH on gelatinization of starch after irradiation were investigated. Paste viscosities were markedly affected by pH on gelatinization and a decrease in the viscosity of irradiated starch was stimulated by increasing pH. On the other hand, the solubility of irradiated starch increased significantly at the high pH. The granule structure of irradiated starch easily disintegrated at alkaline pH. Remarkable dissolution from the surface of the irradiated starch granules was observed after heating at high pH only a filamentous network frame remained, but the unirradiated one collapsed and folded. It was seen that alkali treatment after irradiation reduces the required dose to obtain low viscosity starch. The required dose to produce a low viscosity starch, for example Ajinomoto Essan Sizer 600 grade, was ca. 3 Mrad at pH 11.0 and ca. 5 Mrad at pH 7.0, whereas it was ca. 7 Mrad without pH adjustment. (author)

  10. Chemical modification of chitosan in the absence of solvent for diclofenac sodium removal: pH and kinetics studies

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Kerlaine Alexandre Araujo; Osorio, Luizangela Reis; Silva, Marcos Pereira; Silva Filho, Edson Cavalcanti da, E-mail: edsonfilho@ufpi.edu.br [Universidade Federal do Piaui (UFPI/CCN), Teresina, PI (Brazil). Centro de Ciencias da Natureza. Lab. Interdisciplinar de Materiais Avancados; Sousa, Kaline Soares [Universidade Federal da Paraiba (UFPB/CCEN), Joao Pessoa, PB (Brazil). Centro de Ciencias Exatas e da Natureza. Dept. de Quimica

    2014-08-15

    Chitosan was modified with acetylacetone and ethylenediamine in the absence of solvent. The new biopolymer obtained from the modification was characterized by elemental analysis and NMR 13C and applied in the removal of diclofenac sodium aqueous solution varying the pH and time. Through elemental analysis was possible to verify a decreasing in C/N relation after reaction with acetylacetone and an increasing after modification with ethylenediamine. From NMR analysis was verified the appearance of peaks around 160-210 ppm in both materials due to free carbonyl groups in the first step of the modification, besides the formation of imine bonds. The adsorption tests showed that the highest value occurred at pH 4 and from the results of the kinetic study was found that maximum adsorption occurred within 45 minutes and experimental data adjusted better to linear adjustment, following pseudo second-order model. The results show a material efficient in the removal of emerging pollutants. (author)

  11. Adsorption of phenol by activated carbon: Influence of activation methods and solution pH

    International Nuclear Information System (INIS)

    Cherry stone based activated carbon derived from a canning industry was evaluated for its ability to remove phenol from an aqueous solution in a batch process. A comparative adsorption on the uptake of phenol by using commercial activated carbon (Chemviron CPG-LF), and two non-functional commercial polymeric adsorbents (MN-200 and XAD-2) containing a styrene-divinylbenzene macroporous hyperreticulated network have been also examined. Equilibrium studies were conducted in 25 mg L-1 initial phenol concentrations, 6.5-9 solution pH and at temperature of 30 deg. C. The experimental data were analyzed by the Langmuir and Freundlich isotherm models. Besides, the cherry stone based activated carbons were carried out by using zinc chloride and KOH activation agents at different chemical ratios (activating agent/precursor), to develop carbons with well-developed porosity. The cherry stone activated carbon prepared using KOH as a chemical agent showed a high surface area. According to the results, activated carbons had excellent adsorptive characteristics in comparison with polymeric sorbents and commercial activated carbon for the phenol removal from the aqueous solutions.

  12. Adsorption of phenol by activated carbon: Influence of activation methods and solution pH

    Energy Technology Data Exchange (ETDEWEB)

    Beker, Ulker, E-mail: ubeker@gmail.co [Yildiz Technical University, Chemical Engineering Department, Davutpasa Campus, 34210 Esenler, Istanbul (Turkey); Ganbold, Batchimeg [National University of Mongolia, Faculty of Organic Chemistry, Ikh Surguuliin Gudamj 1, P.O. Box 46a/523, 210646 Ulaanbaatar (Mongolia); Dertli, Halil [Istanbul Technical University, Chemical Engineering Department, Maslak, Istanbul (Turkey); Guelbayir, Dilek Duranoglu [Yildiz Technical University, Chemical Engineering Department, Davutpasa Campus, 34210 Esenler, Istanbul (Turkey)

    2010-02-15

    Cherry stone based activated carbon derived from a canning industry was evaluated for its ability to remove phenol from an aqueous solution in a batch process. A comparative adsorption on the uptake of phenol by using commercial activated carbon (Chemviron CPG-LF), and two non-functional commercial polymeric adsorbents (MN-200 and XAD-2) containing a styrene-divinylbenzene macroporous hyperreticulated network have been also examined. Equilibrium studies were conducted in 25 mg L{sup -1} initial phenol concentrations, 6.5-9 solution pH and at temperature of 30 deg. C. The experimental data were analyzed by the Langmuir and Freundlich isotherm models. Besides, the cherry stone based activated carbons were carried out by using zinc chloride and KOH activation agents at different chemical ratios (activating agent/precursor), to develop carbons with well-developed porosity. The cherry stone activated carbon prepared using KOH as a chemical agent showed a high surface area. According to the results, activated carbons had excellent adsorptive characteristics in comparison with polymeric sorbents and commercial activated carbon for the phenol removal from the aqueous solutions.

  13. Chemical protection of ZnO nanorods at ultralow pH To form a hierarchical BiFeO3/ZnO core-shell structure.

    Science.gov (United States)

    Loh, Leonard; Briscoe, Joe; Dunn, Steve

    2015-01-14

    ZnO is an interesting material for photoactive and optoelectronic devices because of the wide range of available nanostructures and advantageous semiconducting properties. However, a significant drawback of ZnO is the low stability in high or low pH solutions. This has limited the development of ZnO core-shell materials for use in Z-scheme systems or photovoltaics, where any secondary phase is produced using chemical solution processing at low or high pH. Here, we show a simple process to produce an organic capping layer of 3-aminopropyltriethoxysilane that can successfully stabilize nanostructured ZnO for processing below pH 1. We demonstrate that this process can be used to produce a ZnO-BiFeO3 (BFO) core-shell structure by a sol-gel process. Using a range of physical and analytical techniques, we show that BFO is highly crystalline and produces a conformal coating with a thickness of 2.5 nm. X-ray photoelectron spectroscopy and X-ray diffraction confirm the phase and expected chemical composition of BFO. Finally we are able to demonstrate that diodes produced using the ZnO-BFO core-shell structure have improved performance with a rectification ratio at ±3 V of 2800 because of the reduction in reverse current typically associated with surface recombination on ZnO. Our process opens a route to producing a range of hitherto prohibited ZnO core-shell structures that may have applications ranging from photovoltaic devices to core-shell photocatalysts. PMID:25247787

  14. Direct reduction of N-acetoxy-PhIP by tea polyphenols: a possible mechanism for chemoprevention against PhIP-DNA adduct formation

    International Nuclear Information System (INIS)

    The chemopreventive effect of tea against 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-DNA adduct formation and its mechanism were studied. Rats were exposed to freshly prepared aqueous extracts of green tea (3% (w/v)) as the sole source of drinking water for 10 days prior to administration with a single dose of PhIP (10 mg/kg body weight) by oral gavage. PhIP-DNA adducts in the liver, colon, heart, and lung were measured using the 32P-postlabelling technique. Rats pre-treated with tea and given PhIP 20 h before sacrifice had significantly reduced levels of PhIP-DNA adducts as compared with controls given PhIP alone. The possible mechanism of protective effect of tea on PhIP-DNA adduct formation was then examined in vitro. It was found that an aqueous extract of green and black tea, mixtures of green and black tea polyphenols, as well as purified polyphenols could strongly inhibit the DNA binding of N-acetoxy-PhIP, a putative ultimate carcinogen of PhIP formed in vivo via metabolic activation. Among these, epigallocatechin gallate was exceptionally potent. HPLC analyses of these incubation mixtures containing N-acetoxy-PhIP and the tea polyphenols each revealed the production of the parent amine, PhIP, indicating the involvement of a redox mechanism. In view of the presence of relatively high levels of tea polyphenols in rat and human plasma after ingestion of tea, this study suggests that direct reduction of the ultimate carcinogen N-acetoxy-PhIP by tea polyphenols is likely to be involved in the mechanism of chemoprotection of tea against this carcinogen

  15. Soft-tissue sarcomas and exposure to chemical substances: a case-referent study.

    OpenAIRE

    Eriksson, M.; Hardell, L; Berg, N O; T. Möller; Axelson, O

    1981-01-01

    In 1977 several patients were seen with soft-tissue sarcomas and previous exposure to phenoxy acids. This clinical observation resulted in a cases-referent (case-control) study being undertaken which showed that exposure to phenoxy acids or chlorophenols, which are chemically related, gave a roughly six-fold increase in the risk for this type of tumour. A further case-referent study of soft-tissue sarcomas has now been performed to confirm these earlier findings and also to obtain further inf...

  16. Alkaline cyanide degradation by Pseudomonas pseudoalcaligenes CECT5344 in a batch reactor. Influence of pH

    International Nuclear Information System (INIS)

    Water containing cyanide was biologically detoxified with the bacterial strain Pseudomonas pseudoalcaligenes CECT5344 in a batch reactor. Volatilization of toxic hydrogen cyanide (HCN) was avoided by using an alkaline medium for the treatment. The operational procedure was optimized to assess cyanide biodegradation at variable pH values and dissolved oxygen concentrations. Using an initial pH of 10 without subsequent adjustment allowed total cyanide to be consumed at a mean rate of approximately 2.81 mg CN- L-1 O.D.-1 h-1; however, these conditions posed a high risk of HCN formation. Cyanide consumption was found to be pH-dependent. Thus, no bacterial growth was observed with a controlled pH of 10; on the other hand, pH 9.5 allowed up to 2.31 mg CN- L-1 O.D.-1 h-1 to be converted. The combination of a high pH and a low dissolved oxygen saturation (10%) minimized the release of HCN. This study contributes new basic knowledge about this biological treatment, which constitutes an effective alternative to available physico-chemical methods for the purification of wastewater containing cyanide or cyano-metal complexes.

  17. Alkaline cyanide degradation by Pseudomonas pseudoalcaligenes CECT5344 in a batch reactor. Influence of pH

    Energy Technology Data Exchange (ETDEWEB)

    Huertas, M.J., E-mail: mjhuertas@us.es [Instituto de Bioquimica Vegetal y Fotosintesis, CSIC-Universidad de Sevilla Avda Americo Vespucio, 49, 41092 Sevilla (Spain); Saez, L.P.; Roldan, M.D.; Luque-Almagro, V.M.; Martinez-Luque, M. [Departamento de Bioquimica y Biologia Molecular, Edificio Severo Ochoa, 1a Planta, Campus de Rabanales, Universidad de Cordoba, 14071 Cordoba (Spain); Blasco, R. [Departamento de Bioquimica y Biologia Molecular y Genetica, Facultad de Veterinaria, Universidad de Extremadura, 11071 Caceres (Spain); Castillo, F.; Moreno-Vivian, C. [Departamento de Bioquimica y Biologia Molecular, Edificio Severo Ochoa, 1a Planta, Campus de Rabanales, Universidad de Cordoba, 14071 Cordoba (Spain); Garcia-Garcia, I. [Departamento de Ingenieria Quimica, Edificio Marie Curie, Campus de Rabanales, Universidad de Cordoba, 14071 Cordoba (Spain)

    2010-07-15

    Water containing cyanide was biologically detoxified with the bacterial strain Pseudomonas pseudoalcaligenes CECT5344 in a batch reactor. Volatilization of toxic hydrogen cyanide (HCN) was avoided by using an alkaline medium for the treatment. The operational procedure was optimized to assess cyanide biodegradation at variable pH values and dissolved oxygen concentrations. Using an initial pH of 10 without subsequent adjustment allowed total cyanide to be consumed at a mean rate of approximately 2.81 mg CN{sup -} L{sup -1} O.D.{sup -1} h{sup -1}; however, these conditions posed a high risk of HCN formation. Cyanide consumption was found to be pH-dependent. Thus, no bacterial growth was observed with a controlled pH of 10; on the other hand, pH 9.5 allowed up to 2.31 mg CN{sup -} L{sup -1} O.D.{sup -1} h{sup -1} to be converted. The combination of a high pH and a low dissolved oxygen saturation (10%) minimized the release of HCN. This study contributes new basic knowledge about this biological treatment, which constitutes an effective alternative to available physico-chemical methods for the purification of wastewater containing cyanide or cyano-metal complexes.

  18. Identification of the Related Substances in Ampicillin Capsule by Rapid Resolution Liquid Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry

    OpenAIRE

    Lei Zhang; Xian Long Cheng; Yang Liu; Miao Liang; Honghuan Dong; Beiran Lv; Wenning Yang; Zhiqiang Luo; Mingmin Tang

    2014-01-01

    Rapid Resolution Liquid Chromatography coupled with Electrospray Ionization Tandem Mass Spectrometry (RRLC-ESI-MSn) was used to separate and identify related substances in ampicillin capsule. The fragmentation behaviors of related substances were used to identify their chemical structures. Finally, a total of 13 related substances in ampicillin capsule were identified, including four identified components for the first time and three groups of isomers on the basis of the exact mass, fragmenta...

  19. Facilitated transport of titanium dioxide nanoparticles by humic substances in saturated porous media under acidic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruichang [Chinese Academy of Sciences, Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science (China); Zhang, Haibo; Tu, Chen; Hu, Xuefeng; Li, Lianzhen [Chinese Academy of Sciences, Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (China); Luo, Yongming, E-mail: ymluo@yic.ac.cn; Christie, Peter [Chinese Academy of Sciences, Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science (China)

    2015-04-15

    The transport behavior of titanium dioxide nanoparticles (TiO{sub 2} NPs, 30 nm in diameter) was studied in well-defined porous media composed of clean quartz sand over a range of solution chemistry under acidic conditions. Transport of TiO{sub 2} NPs was dramatically enhanced by humic substances (HS) at acidic pH (4.0, 5.0 and 6.0), even at a low HS concentration of 0.5 mg L{sup −1}. Facilitated transport of TiO{sub 2} NPs was likely attributable to the increased stability of TiO{sub 2} NPs and repulsive interaction between TiO{sub 2} NPs and quartz sands due to the adsorbed HS. The mobility of TiO{sub 2} NPs was also increased with increasing pH from 4.0 to 6.0. Although transport of TiO{sub 2} NPs was insensitive to low ionic strength, it was significantly inhibited by high concentrations of NaCl and CaCl{sub 2}. In addition, calculated Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energy indicated that high energy barriers were responsible for the high mobility of TiO{sub 2} NPs, while the secondary energy minimum could play an important role in the retention of TiO{sub 2} NPs at 100 mmol L{sup −1} NaCl. Straining and gravitational settlement of larger TiO{sub 2} NPs aggregates at 1 mg L{sup −1} HS, pH 5.0, and 2 mmol L{sup −1} CaCl{sub 2} could be responsible for the significant retention even in the presence of high energy barriers. Moreover, more favorable interaction between approaching TiO{sub 2} NPs and TiO{sub 2} NPs that had been already deposited on the collector resulted in a ripening-shape breakthrough curve at 2 mmol L{sup −1} CaCl{sub 2}. Overall, a combination of mechanisms including DLVO-type force, straining, and physical filtration was involved in the retention of TiO{sub 2} NPs over the range of solution chemistry examined in this study.

  20. Facilitated transport of titanium dioxide nanoparticles by humic substances in saturated porous media under acidic conditions

    International Nuclear Information System (INIS)

    The transport behavior of titanium dioxide nanoparticles (TiO2 NPs, 30 nm in diameter) was studied in well-defined porous media composed of clean quartz sand over a range of solution chemistry under acidic conditions. Transport of TiO2 NPs was dramatically enhanced by humic substances (HS) at acidic pH (4.0, 5.0 and 6.0), even at a low HS concentration of 0.5 mg L−1. Facilitated transport of TiO2 NPs was likely attributable to the increased stability of TiO2 NPs and repulsive interaction between TiO2 NPs and quartz sands due to the adsorbed HS. The mobility of TiO2 NPs was also increased with increasing pH from 4.0 to 6.0. Although transport of TiO2 NPs was insensitive to low ionic strength, it was significantly inhibited by high concentrations of NaCl and CaCl2. In addition, calculated Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energy indicated that high energy barriers were responsible for the high mobility of TiO2 NPs, while the secondary energy minimum could play an important role in the retention of TiO2 NPs at 100 mmol L−1 NaCl. Straining and gravitational settlement of larger TiO2 NPs aggregates at 1 mg L−1 HS, pH 5.0, and 2 mmol L−1 CaCl2 could be responsible for the significant retention even in the presence of high energy barriers. Moreover, more favorable interaction between approaching TiO2 NPs and TiO2 NPs that had been already deposited on the collector resulted in a ripening-shape breakthrough curve at 2 mmol L−1 CaCl2. Overall, a combination of mechanisms including DLVO-type force, straining, and physical filtration was involved in the retention of TiO2 NPs over the range of solution chemistry examined in this study

  1. Identification of the Related Substances in Ampicillin Capsule by Rapid Resolution Liquid Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2014-01-01

    Full Text Available Rapid Resolution Liquid Chromatography coupled with Electrospray Ionization Tandem Mass Spectrometry (RRLC-ESI-MSn was used to separate and identify related substances in ampicillin capsule. The fragmentation behaviors of related substances were used to identify their chemical structures. Finally, a total of 13 related substances in ampicillin capsule were identified, including four identified components for the first time and three groups of isomers on the basis of the exact mass, fragmentation behaviors, retention time, and chemical structures in the literature. This study avoided time-consuming and complex chemosynthesis of related substances of ampicillin and the results could be useful for the quality control of ampicillin capsule to guarantee its safety in clinic. In the meantime, it provided a good example for the rapid identification of chemical structures of related substances of drugs.

  2. Identification of the related substances in ampicillin capsule by rapid resolution liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Lei; Cheng, Xian Long; Liu, Yang; Liang, Miao; Dong, Honghuan; Lv, Beiran; Yang, Wenning; Luo, Zhiqiang; Tang, Mingmin

    2014-01-01

    Rapid Resolution Liquid Chromatography coupled with Electrospray Ionization Tandem Mass Spectrometry (RRLC-ESI-MS(n)) was used to separate and identify related substances in ampicillin capsule. The fragmentation behaviors of related substances were used to identify their chemical structures. Finally, a total of 13 related substances in ampicillin capsule were identified, including four identified components for the first time and three groups of isomers on the basis of the exact mass, fragmentation behaviors, retention time, and chemical structures in the literature. This study avoided time-consuming and complex chemosynthesis of related substances of ampicillin and the results could be useful for the quality control of ampicillin capsule to guarantee its safety in clinic. In the meantime, it provided a good example for the rapid identification of chemical structures of related substances of drugs. PMID:25530907

  3. Fixation and transport of uranium by humic substances (1962); Fixation et transport de l'uranium par les substances humiques (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1962-03-15

    One enter upon the study of the part taken by organic substances in ores that contain uranium in a disseminated form, without mineralization, being considered the reaction between uranium and humus. 'Humic acids' are extracted from the peat by ammonia. By the fact of their ability to cationic exchange, these are forming humates with metal cations; monovalent humates, normally soluble in water, can become insoluble after treatment of humic acids with methanal. The polyvalent humates are insoluble in water, especially humates of U (IV) and uranyl U (VI). Action of Li, Na, K, Mg, Ca uranyl carbonates solutions on the humic acids results in the formation of humates containing uranyl and the other cation. 100 g of humic acids give a fixation of no more than 38 g of uranium as uranyl. In contact with uraniferous weakly concentrated solutions, they fix 4 to 8 g according to pH, with a yield in the extraction greater than 95 per cent. The action of a sodium humate solution on a humate of uranyl give a solution containing a soluble sodium and uranyl humate. The solution is precipitated at various degrees by the polyvalent cations and insoluble humic substances. In all cases, the fixation of uranium with such prepared humic acids corresponds to a chemisorption of uranyl cations. (author) [French] L'etude du role des matieres organiques dans les minerais contenant de l'uranium sous une forme disseminee, sans mineralisation, est abordee en envisageant les reactions de l'uranium et de l'humus. Des 'acides humiques' sont extraits de la tourbe par l'ammoniaque. Par leur capacite d'echange cationique, ils forment des humates avec les cations metalliques; les humates de metaux monovalents, normalement solubles dans l'eau, peuvent etre rendus insolubles apres traitement des acides humiques par le methanal. Les humates de metaux plurivalents sont insolubles dans l'eau, en particulier ceux de U (IV) et d'uranyle U (VI

  4. Measurement of pH micro-heterogeneity in natural cheese matrices by fluorescence lifetime imaging

    Directory of Open Access Journals (Sweden)

    Zuzana eBurdikova

    2015-03-01

    Full Text Available Cheese, a product of microbial fermentation may be defined as a protein matrix entrapping fat, moisture, minerals and solutes as well as dispersed bacterial colonies. The growth and physiology of bacterial cells in these colonies may be influenced by the microenvironment around the colony, or alternatively the cells within the colony may modify the microenvironment (e.g. pH, redox potential due to their metabolic activity. While cheese pH may be measured at macro level there remains a significant knowledge gap relating to the degree of micro-heterogeneity of pH within the cheese matrix and its relationship with microbial, enzymatic and physiochemical parameters and ultimately with cheese quality, consistency and ripening patterns. The pH of cheese samples was monitored both at macroscopic scale and at microscopic scale, using a non-destructive microscopic technique employing C-SNARF-4 and Oregon Green 488 fluorescent probes. The objectives of this work were to evaluate the suitability of these dyes for microscale pH measurements in natural cheese matrices and to enhance the sensitivity and extend the useful pH range of these probes using fluorescence lifetime imaging (FLIM. In particular, fluorescence lifetime of Oregon Green 488 proved to be sensitive probe to map pH micro heterogeneity within cheese matrices. Good agreement was observed between macroscopic scale pH measurement by FLIM and by traditional pH methods, but in addition considerable localized microheterogeneity in pH was evident within the curd matrix with pH range between 4.0 and 5.5. This technique provides significant potential to further investigate the relationship between cheese matrix physico-chemistry and bacterial metabolism during cheese manufacture and ripening.

  5. Chemical sensors in water analysis - pH value, oxygen and chlorine. Chemische Sensoren in der Wasseranalytik - pH, Sauerstoff und Chlor

    Energy Technology Data Exchange (ETDEWEB)

    Straub, H.

    1993-02-01

    Chemical sensors are used in many sectors of industry as measuring devices providing quantitative information about various quantities. Depending upon the task at hand, amperometric, conductimetric, voltammetric, and potentiometric approaches are all used in water analysis. (orig.)

  6. Isotope separation by chemical exchange

    International Nuclear Information System (INIS)

    Nitrogen-15 and oxygen-18 enrichment by chemical exchange in the (NO/NO2) - (H2O/HNO3) system, using a laboratory-scale experimental plant and a cascade for production of two isotopes, is presented. The results obtained from the laboratory-scale plant indicate that optimal flow rate for 15N separation is 1.55 - 1.86 ml/cm2 · min at 8 - 10 M/l nitric acid and 63.4 mg at. oxygen/cm2 · min for 18O separation at 5.8 M/l nitric acid. The height equivalent to a theoretical plate (HETP) of 4.11 - 4.56 cm is in good agreement with other published data for 15N separation using exchange column with Helipak packing. The HETP of 7.74 - 10.58 cm for 18O separation is greater by 20 - 30 % than those presented by Saxena and Taylor for 'Helipak' column packing, but in good agreement with the HRTP published by Borisov et al. on 'Levina' column packing. The HETP obtained for 15N separation by the production plant is in the range 11.5 - 13.8 cm at a flow rate of 2.2 ml HNO3(10M/l)/cm2 · min for the first column and 4.4 - 4.7 cm at a flow rate of 1.66 ml HNO3(10M/l)/cm2 · min for the second column. The optimal flow rate for 18O separation by the production plant is about 63 mg at. oxygen/cm2 · min (1.01 ml HNO3/cm2 · min). Enrichment of 13C and 18O by chemical exchange of carbon dioxide with its monoethanolamine carbamate in methanol and di-n-butylamine carbamate in triethylamine has also been studied, and optimum operating conditions for the separation of 13C in a packed column was determined. The HETP obtained for the 13C in a packed column was determined. The HETP obtained for the 13C separation column is 3.62 - 8.26 cm at a flow rate of 1.1 - 4.0 mmol carbamate/cm2 · min using the same column packing as for 15N and 18O separation, that is, stainless steel triangular wire springs (2.3 x 2.3 x 0.2 mm). (author)

  7. 78 FR 35922 - Endocrine Disruptor Screening Program; Final Second List of Chemicals and Substances for Tier 1...

    Science.gov (United States)

    2013-06-14

    ... water contaminants and pesticides previously identified by EPA. These priority chemicals included the... Screening Program (EDSP). The EDSP is established under section 408(p) of the Federal Food, Drug, and... the Federal Food, Drug, and Cosmetic Act (FFDCA), which requires EPA to develop a chemical...

  8. Different scale experimental techniques to approach the problem of substances generated in the loss of control of chemical systems: a study on ethyl diazoacetate decomposition

    NARCIS (Netherlands)

    Marsanich, K.; Barontini, F.; Cozzani, V.; Creemers, A.F.L.; Kersten, R.J.A.

    2004-01-01

    Article 2 of European Community Directive 96/82/EC (known as 'Seveso-II' Directive) also requires consideration in the plant inventory of the dangerous substances 'which it is believed may be generated in the loss of control of an industrial chemical process'. The present study was directed to the f

  9. The influence of redox chemistry and pH on chemically active forms of arsenic in sewage sludge-amended soil

    Energy Technology Data Exchange (ETDEWEB)

    Carbonell-Barrachina, A.; Jugsujinda, A.; DeLaune, R.D.; Patrick, W.H. Jr. [Louisiana State Univ., Baton Rouge, LA (United States). Wetland Biogeochemistry Inst.; Burlo, F. [Univ. Miguel Hernandez, Alicante (Spain). Div. Tecnologia de Alimentos; Sirisukhodom, S. [Mahidol Univ., Bangkok (Thailand). Environmental Health Science Dept.; Anurakpongsatorn, P. [Kasetsart Univ., Bangkok (Thailand). Dept. of Environmental Science

    1999-07-01

    Chemical fractionation procedures were used to quantify the effect of the sediment redox and pH conditions on the adsorption and solubility of arsenic (As) in municipal sewage sludge and sewage sludge-amended soil. Sludge and sludge-amended soil were incubated in microcosms in which Eh-pH conditions were controlled. Samples were sequentially extracted to determine As in various chemical forms (water soluble, exchangeable, bound to carbonates, bound to iron (Fe) and manganese (Mn) oxides, bound to insoluble organics and sulfides) and the chemically inactive fraction (mineral residues). In both sewage sludge and sludge-amended soil, As chemistry was governed by large molecular humic matter and sulfides and Fe and Mn-oxides. Solubility of As remained low and constant under both aerobic and anaerobic conditions in sludge-amended soil. After dissolution of Fe and Mn-oxides, As{sup 5+} was released into sludge solution, reduced to As{sup 3+} and likely precipitated as sulfide. Therefore, an organic amendment rich in sulfur compounds, such as sewage sludge, would drastically reduce the potential risks derived from As pollution under highly anoxic conditions by precipitation of this toxic metalloid as insoluble and immobile sulfides.

  10. Reducing the Risks. In the aftermath of a terrorist attack, wastewater utilities may have to contend with decontamination water containing chemical, biological, or radiological substances

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Linda P.; Hornback, Chris; Strom, Daniel J.

    2006-08-01

    In the aftermath of a chemical, biological, or radiological (CBR) attack, decontamination of people and infrastructure will be needed. Decontamination inevitably produces wastewater, and wastewater treatment plants (WTPs) need to know how to handle decontamination wastewater. This article describes CBR substances; planning, coordinating, and communicating responses across agencies; planning within a utility; coordination with local emergency managers and first responders; mitigating effects of decontamination wastewater; and mitigating effects on utility personnel. Planning for Decontamination Wastewater: A Guide for Utilities, the document on which this article is based, was developed under a cooperative agreement from the U.S. Environmental Protection Agency by the National Association of Clean Water Agencies (NACWA) and its contractor, CH2MHILL, Inc.

  11. Effects of pH on the characteristics of ZnS thin films grown by using the CBD method

    Science.gov (United States)

    Ahn, Heejin; Lee, Dongchan; Park, Sujung; Um, Youngho

    In CIGS-based thin film solar cells, a chemically deposited ZnS buffer layer with high resistivity is generally used between the absorber layer and transparent conducting oxide layer. In this work, we report a chemical process to prepare ZnS films by the CBD technique based on the typical bath deposition. The influences of ammonia (NH4OH) and Na2EDTA (Na2C10H16N2O8) as complexing agents on structural, morphological, and optical properties of ZnS thin films are investigated ranging pH concentration from 5 to 10. To investigate effects of pH on the characteristics of ZnS thin films, by using UV-visible transmittance, atomic force microscopy, and optical absorption were investigated. With changing the pH range, the ZnS thin films demonstrate high transmittance of 75~80% in the visible region, indicating the films are potentially useful in photovoltaic applications. The results will be presented in detail. This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education (2011-0024709).

  12. High-rate volatile fatty acid (VFA) production by a granular sludge process at low pH.

    Science.gov (United States)

    Tamis, J; Joosse, B M; Loosdrecht, M C M van; Kleerebezem, R

    2015-11-01

    Volatile fatty acids (VFA) are proposed platform molecules for the production of basic chemicals and polymers from organic waste streams. In this study we developed a granular sludge process to produce VFA at high rate, yield and purity while minimizing potential operational costs. A lab-scale anaerobic sequencing batch reactor (ASBR) was fed with 10 g l(-1) glucose as model substrate. Inclusion of a short (2 min) settling phase before effluent discharge enabled effective granulation and very high volumetric conversion rates of 150-300 gCOD l(-1)  d(-1) were observed during glucose conversion. The product spectrum remained similar at the tested pH range with acetate and butyrate as the main products, and a total VFA yield of 60-70% on chemical oxygen demand (COD) basis. The requirement for base addition for pH regulation could be reduced from 1.1 to 0.6 mol OH(-) (mol glucose)(-1) by lowering the pH from 5.5 to 4.5. Solids concentrations in the effluent were 0.6 ± 0.3 g l(-1) but could be reduced to 0.02 ± 0.01 g l(-1) by introduction of an additional settling period of 5 min. The efficient production of VFA at low pH with a virtually solid-free effluent increases the economic feasibility of waste-based chemicals and polymer production. Biotechnol. PMID:25950759

  13. Degradation behaviour of pyrazosulfuron-ethyl in water as affected by pH.

    Science.gov (United States)

    Singh, Shashi B; Singh, Neera

    2013-01-01

    Pyrazosulfuron-ethyl, a new herbicide belonging to the sulfonylurea group, is used for weed control in rice crops growing in areas varying from acidic to alkaline soils. This study was undertaken to determine the degradation behaviour of pyrazosulfuron-ethyl in distilled water and buffer solutions at pH 4, 7 and 9. Degradation was pH-dependent and herbicide was least persistent in acidic pH followed by alkaline and neutral pH. The half-life of pyrazosulfuron-ethyl varied from 2.6 days (pH 4) to 19.4 days (pH 7) and half-life in distilled water was comparable to half-life at pH 7 buffer. HPLC analysis of different pH samples showed the formation of three metabolites viz., 5-(aminosulfonyl)-1-methyl-1H-pyrazole-4-carboxylic acid; ethyl 5-(aminosulfonyl)-1-methyl-1H-pyrazole-4-carboxylate and 2-amino-4,6-dimethoxy pyrimidine. The formation of pyrazosulfuron acid [5-([([(4,6-dimethoxy-2 pyrimidinyl)-amino]-carbonyl) amino]-sulfonyl)-1-methyl-1H-pyrazole-4-carboxylic acid] was not observed at any pH. The study indicated that the herbicide was least stable under acidic conditions and the predominant degradation route of pyrazosulfuron-ethyl in water is hydrolysis of sulfonamide linkage. PMID:23374044

  14. Influence of pH on yeast immobilization on polystyrene surfaces modified by energetic ion bombardment.

    Science.gov (United States)

    Tran, Clara T H; Kondyurin, Alexey; Chrzanowski, Wojciech; Bilek, Marcela M M; McKenzie, David R

    2013-04-01

    Plasma immersion ion implantation (PIII) treatment is a novel method for immobilizing yeast on polymer surfaces by covalent linkage. This study of the immobilization of Saccharomyces cerevisiae in both rehydrated and cultured forms showed that the density of cell attachment on PIII treated polystyrene (PS) was strongly dependent on the pH of the incubation medium and was higher for rehydrated yeast. A study of the surface charge was undertaken to explain this result. A high density of cell attachment occurs in acidic conditions (pH 3-5) and a significantly reduced cell density occurs in neutral and alkaline buffers (pH 6-10) for both types of yeast. Force measurements using atomic force microscopy show that a negative charge is present on polystyrene after PIII treatment. The charge is close to zero at pH 3 to pH 5 and increasingly negative from pH 6 to pH 10. Both rehydrated yeast and cultured yeast have negative electrophoretic mobility in the pH range studied. The repulsive forces are weak in acidic buffers and stronger in neutral and alkaline buffers, in good agreement with the cell densities observed. Rehydrated yeast cells are found to be more hydrophobic than cultured yeasts in the same buffer. The higher hydrophobicity explains the higher attachment of rehydrated yeast compared to cultured yeast. PMID:23298600

  15. TRICHLOROETHYLENE ADSORPTION BY ACTIVATED CARBON PRELOADED WITH HUMIC SUBSTANCES: EFFECTS OF SOLUTION CHEMISTRY. (R828157)

    Science.gov (United States)

    AbstractTrichloroethylene (TCE) adsorption by activated carbon previously loaded ("preloaded") with humic substances was found to decrease with increasing concentrations of monovalent ions (NaCl), calcium (until solubility was exceeded), or dissolved oxygen in...

  16. pH within pores in plant fiber cell walls assessed by Fluorescence Ratio Imaging

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Thygesen, Lisbeth Garbrecht; Johansen, Katja S.

    2013-01-01

    The pH within cell wall pores of filter paper fibers and hemp fibers was assessed by Fluorescence Ratio Imaging (FRIM). It was found that the Donnan effect affected the pH measured within the fibers. When the conductivity of the added liquid was low (0. 7 mS), pH values were lower within the cell...... wall than in the bulk solution. This was not the case at high conductivity (22 mS). The occurrence of the Donnan effect allowed the pH values within pores in normal regions of the cell wall to be compared to the pH in regions with misaligned microfibrils (dislocations) when FRIM was carried out in a...

  17. Determination and validation of zonisamide and its four related substances by HPLC and UV-spectrophotometry

    Directory of Open Access Journals (Sweden)

    Hosseini Maryam

    2010-01-01

    Full Text Available A selective and sensitive liquid chromatographic method has been developed for simultaneous determination of zonisamide and its four related substances in pharmaceutical dosage forms. The assay involved an isocratic elution in perfectsil Target C18 column using a mobile phase composition of disodium hydrogen phosphate buffer, acetonitrile and methanol (650:150:200 v/v, pH adjusted to 3±0.05 with flow rate 1.2 ml/min and analyte monitored at 240 nm. Also a simple and precise spectrophotometric method was developed for dissolution studies. These proposed methods are sensitive, accurate, reproducible and useful for the routine determination of zonisamide in pharmacy.

  18. Determination and validation of zonisamide and its four related substances by HPLC and UV-spectrophotometry

    OpenAIRE

    Hosseini Maryam; Alipour E; Farokhsir Arezou

    2010-01-01

    A selective and sensitive liquid chromatographic method has been developed for simultaneous determination of zonisamide and its four related substances in pharmaceutical dosage forms. The assay involved an isocratic elution in perfectsil Target C18 column using a mobile phase composition of disodium hydrogen phosphate buffer, acetonitrile and methanol (650:150:200 v/v, pH adjusted to 3±0.05) with flow rate 1.2 ml/min and analyte monitored at 240 nm. Also a simple and precise spectrophoto...

  19. Distinctive sorption mechanisms of 4-chlorophenol with black carbons as elucidated by different pH.

    Science.gov (United States)

    Shih, Yang-hsin; Su, Yuh-fan; Ho, Ren-yu; Su, Po-hsin; Yang, Chien-ying

    2012-09-01

    Black carbon (BC) has been considered as an important sorbent in the environment in recent years due to its high sorption capacity and unique sorption behavior. Sorption characteristics of black carbons from two main sources were investigated to get a better understanding of organic chemical fate in the environment. The present study showed sorption mechanisms of 4-chlorophenol, a common organic contaminant in the surroundings, in two kinds of black carbons, soot surrogate (BC1) and environmental char (BC2) derived from rice straw. Sorption capacity of 4-chlorophenol was much higher in BC1 than on BC2 due to the larger surface area of BC1. However, the surface-area normalized sorption coefficients (sorption capacity per surface area) of BC2 were higher than those of BC1, indicating electrostatic attraction and actions of polar foundational groups on BC2 can react with 4-chlorophenol. With increasing temperature, sorption of BC1 decreased but the sorption of BC2 significantly increased at pH 10 and only slightly increased at pH 4. An exothermic sorption reaction was found for BC1; however, an endothermic reaction of chemical sorption occurred on BC2 at pH 10 due to the electrostatic attraction. At pH4, sorption capacity of BC2 decreased and the small positive sorption enthalpy indicated that less electrostatic attractions occurred because of the neutral form of 4-chlorophenol and the domination of mainly hydrophobic interactions. PMID:22842752

  20. Hypnotics and mortality-partial confounding by disease, substance abuse and socioeconomic factors?

    DEFF Research Database (Denmark)

    Kriegbaum, Margit; Hendriksen, C.; Vass, Mikkel;

    2016-01-01

    ) and 95% confidence intervals (CI). RESULTS: When covariates were entered one at a time, the changes in HR estimates showed that psychiatric disease, socioeconomic position and substance abuse reduced the excess risk by 17-36% in the low user group and by 45-52% in the high user group. Somatic disease...... this study point at psychiatric disease, substance abuse and socioeconomic position as potential confounding factors partly explaining the association between use of hypnotics and all-cause mortality....

  1. An analysis of the job satisfaction of substance abuse counselors certified by the Commonwealth of Virginia

    OpenAIRE

    Evans, William Nelson

    1993-01-01

    Licensed substance abuse programs in the Commonwealth of Virginia are reporting turnover rates for counselors of up to 60%. Studies have indicated that low job satisfaction can be a cause for turnover in the human services professions. The entire population of substance abuse counselors certified by the Commonwealth of Virginia was surveyed by mail, using a Modified Minnesota satisfaction Questionnaire and an Individual Information Form. Of the 496 possible responses, ...

  2. Molecular Components of the Neurospora crassa pH Signaling Pathway and Their Regulation by pH and the PAC-3 Transcription Factor.

    Science.gov (United States)

    Virgilio, Stela; Cupertino, Fernanda Barbosa; Bernardes, Natália Elisa; Freitas, Fernanda Zanolli; Takeda, Agnes Alessandra Sekijima; Fontes, Marcos Roberto de Mattos; Bertolini, Maria Célia

    2016-01-01

    Environmental pH induces a stress response triggering a signaling pathway whose components have been identified and characterized in several fungi. Neurospora crassa shares all six components of the Aspergillus nidulans pH signaling pathway, and we investigate here their regulation during an alkaline pH stress response. We show that the N. crassa pal mutant strains, with the exception of Δpal-9, which is the A. nidulans palI homolog, exhibit low conidiation and are unable to grow at alkaline pH. Moreover, they accumulate the pigment melanin, most likely via regulation of the tyrosinase gene by the pH signaling components. The PAC-3 transcription factor binds to the tyrosinase promoter and negatively regulates its gene expression. PAC-3 also binds to all pal gene promoters, regulating their expression at normal growth pH and/or alkaline pH, which indicates a feedback regulation of PAC-3 in the pal gene expression. In addition, PAC-3 binds to the pac-3 promoter only at alkaline pH, most likely influencing the pac-3 expression at this pH suggesting that the activation of PAC-3 in N. crassa results from proteolytic processing and gene expression regulation by the pH signaling components. In N. crassa, PAC-3 is proteolytically processed in a single cleavage step predominately at alkaline pH; however, low levels of the processed protein can be observed at normal growth pH. We also demonstrate that PAC-3 preferentially localizes in the nucleus at alkaline pH stress and that the translocation may require the N. crassa importin-α since the PAC-3 nuclear localization signal (NLS) has a strong in vitro affinity with importin-α. The data presented here show that the pH signaling pathway in N. crassa shares all the components with the A. nidulans and S. cerevisiae pathways; however, it exhibits some properties not previously described in either organism. PMID:27557053

  3. An optimized buffer system for NMR-based urinary metabonomics with effective pH control, chemical shift consistency and dilution minimization.

    Science.gov (United States)

    Xiao, Chaoni; Hao, Fuhua; Qin, Xiaorong; Wang, Yulan; Tang, Huiru

    2009-05-01

    NMR-based metabonomics has been widely employed to understand the stressor-induced perturbations to mammalian metabolism. However, inter-sample chemical shift variations for metabolites remain an outstanding problem for effective data mining. In this work, we systematically investigated the effects of pH and ionic strength on the chemical shifts for a mixture of 9 urinary metabolites. We found that the chemical shifts were decreased with the rise of pH but increased with the increase of ionic strength, which probably resulted from the pH- and ionic strength-induced alteration to the ionization equilibrium for the function groups. We also found that the chemical shift variations for most metabolites were reduced to less than 0.004 ppm when the pH was 7.1-7.7 and the salt concentration was less than 0.15 M. Based on subsequent optimization to minimize chemical shift variation, sample dilution and maximize the signal-to-noise ratio, we proposed a new buffer system consisting of K(2)HPO(4) and NaH(2)PO(4) (pH 7.4, 1.5 M) with buffer-urine volume ratio of 1 : 10 for human urinary metabonomic studies; we suggest that the chemical shifts for the proton signals of citrate and aromatic signals of histidine be corrected prior to multivariate data analysis especially when high resolution data were employed. Based on these, an optimized sample preparation method has been developed for NMR-based urinary metabonomic studies. PMID:19381385

  4. REACH. Analytical characterisation of petroleum UVCB substances

    Energy Technology Data Exchange (ETDEWEB)

    De Graaff, R.; Forbes, S.; Gennart, J.P.; Gimeno Cortes, M.J.; Hovius, H.; King, D.; Kleise, H.; Martinez Martin, C.; Montanari, L.; Pinzuti, M.; Pollack, H.; Ruggieri, P.; Thomas, M.; Walton, A.; Dmytrasz, B.

    2012-10-15

    The purpose of this report is to summarise the findings of the scientific and technical work undertaken by CONCAWE to assess the feasibility and potential benefit of characterising petroleum UVCB substances (Substances of Unknown or Variable Composition, Complex reaction products or Biological Materials) beyond the recommendations issued by CONCAWE for the substance identification of petroleum substances under REACH. REACH is the European Community Regulation on chemicals and their safe use (EC 1907/2006). It deals with the Registration, Evaluation, Authorisation and Restriction of Chemical substances. The report is based on Member Company experience of the chemical analysis of petroleum UVCB substances, including analysis in support of REACH registrations undertaken in 2010. This report is structured into four main sections, namely: Section 1 which provides an introduction to the subject of petroleum UVCB substance identification including the purpose of the report, regulatory requirements, the nature of petroleum UVCB substances, and CONCAWE's guidance to Member Companies and other potential registrants. Section 2 provides a description of the capabilities of each of the analytical techniques described in the REACH Regulation. This section also includes details on the type of analytical information obtained by each technique and an evaluation of what each technique can provide for the characterisation of petroleum UVCB substances. Section 3 provides a series of case studies for six petroleum substance categories (low boiling point naphthas, kerosene, heavy fuel oils, other lubricant base oils, residual aromatic extracts and bitumens) to illustrate the value of the information derived from each analytical procedure, and provide an explanation for why some techniques are not scientifically necessary. Section 4 provides a summary of the conclusions reached from the technical investigations undertaken by CONCAWE Member Companies, and summarising the

  5. Chemical durability and leaching mechanism of Ce0.5Eu0.5PO4 ceramics: Effects of temperature and pH values

    Science.gov (United States)

    Zhao, Xiaofeng; Teng, Yuancheng; Wu, Lang; Huang, Yi; Ma, Jiyan; Wang, Guolong

    2015-11-01

    Ce0.5Eu0.5PO4 ceramics with high relative density were prepared by hot-press (HPS) and pressureless (PLS) sintering. The effects of temperature and pH values on the chemical durability of the ceramics were investigated. The results show that an increase of acidity significantly accelerated the corrosion of the samples. In alkaline leachates, further release elements were prevented by the newborn surface precipitation. The leach rate (Rn) of HPS sample was similar to that of PLS specimen in deionized water, but higher Rn for PLS sample was found in pH = 11 solution. Moreover, apparent activation energy of the dissolution of Eu (40 ± 4 kJ mol-1) is much higher than that of Ce (20 ± 1 kJ mol-1), leading to the higher normalized elemental leach rate of Eu. Both the Eu and Ce elements have low leach rates (10-12-10-9 m d-1) after 42 days in all the leachates studied in this work.

  6. Chemical and light absorption properties of humic-like substances from biomass burning emissions under controlled combustion experiments

    Science.gov (United States)

    Park, Seung Shik; Yu, Jaemyeong

    2016-07-01

    PM2.5 samples from biomass burning (BB) emissions of three types - rice straw (RS), pine needles (PN), and sesame stems (SS) - were collected through laboratory-controlled combustion experiments and analyzed for the mass, organic and elemental carbon (OC and EC), water-soluble organic carbon (WSOC), humic-like substances (HULIS), and water soluble inorganic species (Na+, NH4+, K+, Ca2+, Mg2+, Cl-, NO3-, SO42-, and oxalate). The combustion experiments were carried out at smoldering conditions. Water-soluble HULIS in BB samples was isolated using a one-step solid phase extraction method, followed by quantification with a total organic carbon analyzer. This study aims to explore chemical and light absorption characteristics of HULIS from BB emissions. The contributions of HULIS (=1.94 × HULIS-C) to PM2.5 emissions were observed to be 29.5 ± 2.0, 15.3 ± 3.1, and 25.8 ± 4.0%, respectively, for RS, PN, and SS smoke samples. Contributions of HULIS-C to OC and WSOC for the RS, PN, and SS burning emissions were 0.26 ± 0.03 and 0.63 ± 0.05, 0.15 ± 0.04 and 0.36 ± 0.08, and 0.29 ± 0.08 and 0.51 ± 0.08, respectively. Light absorption by the water extracts from BB aerosols exhibited strong wavelength dependence, which is characteristic of brown carbon spectra with a sharply increasing absorption as wavelength decreases. The average absorption Ångström exponents (AAE) of the water extracts (WSOC) fitted between wavelengths of 300-400 nm were 8.3 (7.4-9.0), 7.4 (6.2-8.5), and 8.0 (7.1-9.3) for the RS, PN, and SS burning samples, which are comparable to the AAE values of BB samples reported in previous publications (e.g., field and laboratory chamber studies). The average mass absorption efficiencies of WSOC measured at 365 nm (MAE365) were 1.37 ± 0.23, 0.86 ± 0.09, and 1.38 ± 0.21 m2/gṡC for RS, PN, and SS burning aerosols, respectively. Correlations of total WSOC, hydrophilic WSOC (= total WSOC-HULIS-C), and HULIS-C concentrations in solution with the light

  7. Environmental pollution by persistent toxic substances and health risk in an industrial area of China

    Institute of Scientific and Technical Information of China (English)

    Jing Li; Yonglong Lu; Yajuan Shi; Tieyu Wang; Guang Wang; Wei Luo; Wentao Jiao; Chunli Chen; Feng Yan

    2011-01-01

    Soil is an important environmental medium that is closely associated with humans and their health.Despite this,very few studies have measured toxicants in soils,and associated them with health risks in humans.An assessment of health effects from exposure to contaminants in soils surrounding industrial areas of chemical production and storage is important.This article aims at determining pollution characteristics of persistent toxic substances (PTS) in an industrial area in China to unravel the relationship between soil pollution by PTS and human health.One hundred and five soil samples were collected and 742 questionnaires were handed out to residents living in and around an industrial area around Bohai Bay,Tianjin in Northern China.Concentrations of organochlorine pesticides and polycyclic aromatic hydrocarbons (PAHs) were determined in soil.Mann-Whitney U and binary multivariate nonconditional logistic regression models were employed to analyze the relationship between health indicators of local residents and contaminant levels.Odds ratio (OR) and a 95% confidence interval (CI) for health incidences were also calculated.The average concentrations of DDT (73.9 rig/g),HCH (654 ng/g) and PAHs (1225 ng/g) were relatively high in the industrial area.Residents living in the chemical industry parks were exposed to a higher levels of PTS than those living outside the chemical industry parks.This exposure was associated with a higher risk of breast cancer (OR 1.87,95% CI 0.12-30.06),stomach cancer (OR 1.87,95% CI 0.26-13.41),dermatitis (OR 1.72,95% CI 1.05-2.80),gastroenteritis (OR 1.59,95% CI 0.94-2.68),and pneumonia (OR 1.05,95% CI 0.58-1.89).

  8. Risks posed by ionizing radiation and chemo-toxic substances

    International Nuclear Information System (INIS)

    Concern over the risks from exposure to radiation or chemical toxins now appears to be forming an integral part of everyday life for a large percentage of the population. In this volume, attempts have therefore been made to compile well documented information relating to those topics as well as to give insights into relevant interconnections and to elucidate certain terms that are not closely enough defined or even have contradictory uses. In the two introductory reports, the multifarious perceptions of what may constitute a risk are outlined and discussed on a large scale stretching from mathematical to purely intuitive factors. The subsequent contributions focus on individual aspects pertinent to dangers from ionizing rays and chemical toxins and examine their wider implications in terms of social, ethical and psychological influences. Of the ten contributions to this volume two were prepared for individual retrieval. (orig./MG)

  9. Gender Minority Social Stress in Adolescence: Disparities in Adolescent Bullying and Substance Use by Gender Identity

    OpenAIRE

    Reisner, Sari L.; Greytak, Emily A; Parsons, Jeffrey T.; Ybarra, Michele

    2014-01-01

    Bullying and substance use represent serious public health issues facing adolescents in the U.S. Few large-sample national studies have examined differences in these indicators by gender identity. The Teen Health and Technology Study (N=5,542) sampled adolescents 13–18 years-old online. Weighted multivariable logistic regression models investigated disparities in substance use and tested a gender minority social stress hypothesis, comparing gender minority youth (i.e., who are transgender/gen...

  10. Influence of chosen microbes and some chemical substances on the production of aflatoxins

    OpenAIRE

    Iveta Brožková; Petra Šmahová; Jarmila Vytřasová; Petra Moťková; Marcela Pejchalová; David Šilha

    2015-01-01

    Aflatoxins are produced as secondary metabolites by A. flavus, A. parasiticus, A. nomius and A. tamarii. The aflatoxin biosynthetic pathway involves several enzymatic steps and genes (apa-2, ver-1) that appear to be regulated by the aflR gene in these fungi. The aim of this work was the detection of aflatoxins by the HPLC method and the ascertainment of factors influencing their production. A. parasiticus CCM F-108, A. parasiticus CCF 141, A. parasiticus CCF 3137 and two isola...

  11. Role of pH value during chemical reaction, and site occupancy of Ni2+ and Fe3+ ions in spinel structure for tuning room temperature magnetic properties in Ni1.5Fe1.5O4 ferrite

    Science.gov (United States)

    Kumar, K. S. Aneesh; Bhowmik, R. N.; Mahmood, Sami H.

    2016-05-01

    The magnetic properties of Ni1.5Fe1.5O4 ferrite have been investigated using the techniques of dc magnetometry and Mӧssbauer spectroscopy. The material has been prepared by chemical reaction of metal nitrates at different pH values and subsequently, annealed at different temperatures to improve the microstructure. The samples with single-phased cubic spinel structure have been used for magnetic study. The material showed a variety of magnetic features, including superparamagnetic and soft ferromagnetic properties. At room temperature, changes of the ferromagnetic parameters of the material have been found in the range 0-47 emu/g for spontaneous magnetization, 0-0.37 for squareness, and 0-195 Oe for coercivity. Variation of the pH value during chemical reaction and changes of the grain size by thermal treatment played an important role in tuning the coexisting superparamagnetic and ferromagnetic components in the material. Samples prepared at high pH value showed small grain size and superparamagnetic features, whereas the samples prepared at low pH value produced large grain size and better ferromagnetic features. The ferromagnetic properties of the material have been enhanced by lowering the pH value and increasing the annealing temperature. Mössbauer spectra provided insight of the local magnetic order, site occupancy of Ni and Fe ions and oxidation state of Fe ions in the spinel structure of Ni1.5Fe1.5O4 ferrite.

  12. Ph3CCOOSnPh3.Ph3PO AND Ph3CCOOSnPh3.Ph3AsO: SYNTHESIS AND INFRARED STUDY

    OpenAIRE

    ABDOU MBAYE; ALEXIS BIENVENU BELEKE; CHEIKH ABDOUL KHADIR DIOP; LIBASSE DIOP

    2014-01-01

    The mixture of ethanolic solutions of Ph3CCOOSnPh3 and Ph3PO or Ph3AsO gives Ph3CCOOSnPh3.Ph3PO and Ph3CCOOSnPh3.Ph3AsO adducts which have been characterized by infrared spectroscopy. A discrete structure is suggested for both, the environment around the tin centre being trigonal bipyramidal, the triphenylacetate anion behaving as a mondentate ligand.

  13. Ph3CCOOSnPh3.Ph3PO AND Ph3CCOOSnPh3.Ph3AsO: SYNTHESIS AND INFRARED STUDY

    Directory of Open Access Journals (Sweden)

    ABDOU MBAYE

    2014-08-01

    Full Text Available The mixture of ethanolic solutions of Ph3CCOOSnPh3 and Ph3PO or Ph3AsO gives Ph3CCOOSnPh3.Ph3PO and Ph3CCOOSnPh3.Ph3AsO adducts which have been characterized by infrared spectroscopy. A discrete structure is suggested for both, the environment around the tin centre being trigonal bipyramidal, the triphenylacetate anion behaving as a mondentate ligand.

  14. Method and device to extract dissolved, suspended or chemically bonded substances from a liquid

    International Nuclear Information System (INIS)

    For extraction of uranium or other minerals from seawater a thin, large-area, disk-type adsorber body is proposed, that may be fastened to a buoy. By means of a rope it may be pleated like an umbrella and easily exchanged. The body has got a diameter of about 56 m; it contains pellets of titanium hydroxide. An automatic system operating by means of a wind power engine is also outlined. (RB)

  15. Chemical reaction directed oriented attachment: from precursor particles to new substances

    OpenAIRE

    Liu, Yongfei; Qin, Xiaoying; Yang, Yong; Zeng, Zhi; Xin, Hongxing; Dai, Zhengfei; Song, Chunjun; Zhu, Xiaoguang; Li, Di; Zhang, Jian; Kawazoe, Yoshiyuki

    2015-01-01

    As a nonclassical crystal growth mode, oriented attachment (OA) plays an increasingly important role in materials science and nanotechnology, and has shown great significance in the development of crystal growth theory. The OA process usually involves the oriented self-assembly of primary nanoparticles and conversion to single crystals or pseudocrystals by interface fusion (Fig. 1a). It is theorized that the OA process is dominant in the early stage of crystal growth, driven by the Brownian m...

  16. Removal of toxic substances by a selective membrane plasma separator.

    Science.gov (United States)

    Nakae, Hajime; Hattori, Tomoko; Igarashi, Toshiko; Okuyama, Manabu; Tajimi, Kimitaka

    2014-06-01

    We devised a method of plasma exchange with dialysis (PED), in which selective plasma exchange (sPE) is performed using a selective membrane plasma separator (EC-2A) with an albumin-sieving coefficient of 0.3 while the dialysate flows outside the hollow fibers, and reported the usefulness of the system for treating acute liver failure. Thereafter, EC-4A with an albumin-sieving coefficient of 0.6 was developed, which was expected to be even more effective for removing protein-bound substances. In order to examine whether or not EC-4A might be applicable to blood purification therapy against drug poisoning, we compared the efficacies of sPE, PED, and direct hemoperfusion (DHP) using an activated carbon column for the removal of phenobarbital and lithium. Subjects undergoing the extracorporeal circulation study were assigned to the sPE group, PED group, or DHP group, and the changes in the blood concentrations of phenobarbital and lithium were measured over 180 min. A significant decrease of the phenobarbital concentration over time was seen in the PED group, as compared to that in the sPE group (P < 0.0001), while no significant difference in the concentration was observed between the PED and DHP groups. The PED group showed a significant decrease of the lithium concentration over time, as compared to the DHP group (P < 0.0001), while no significant difference in the concentration was observed between the PED and sPE groups. Thus, PED was as effective as DHP for removing phenobarbital and was as effective as sPE for removing lithium. These results suggest that PED therapy using EC-4A may be a feasible modality for the treatment of drug poisoning. PMID:24965293

  17. THE EFFECT OF pH ON BIOACCUMULATION OF Cd, Hg AND Pb BY WATER HYACINTH

    OpenAIRE

    Syahrul, Muh.

    2014-01-01

    Water hyacinth grows and multiplies rapidly in the water contaminated by heavy metals such as Cd, Hg, and Pb.. The water hyacinth was planted in Long Ashton media at varying pH, concentrations of Cd, Hg, and Pb and planting time. The roots adsorbed more Cd, Hg and Pb than the stalks and leaves. The maximum absorption was found at pH 5.0 and the minimum at pH 7.0. The higher the metal concentration in the media and longer the planting time, the absorption of the metal ion increased co...

  18. The Role of Intuitive Heuristics in Students' Thinking: Ranking Chemical Substances

    Science.gov (United States)

    Maeyer, Jenine; Talanquer, Vicente

    2010-01-01

    The characterization of students' cognitive biases is of central importance in the development of curriculum and teaching strategies that better support student learning in science. In particular, the identification of shortcut reasoning procedures (heuristics) used by students to reduce cognitive load can help us devise strategies to foster the…

  19. Reasoning about Benefits, Costs, and Risks of Chemical Substances: Mapping Different Levels of Sophistication

    Science.gov (United States)

    Cullipher, S.; Sevian, H.; Talanquer, V.

    2015-01-01

    The ability to evaluate options and make informed decisions about problems in relevant contexts is a core competency in science education that requires the use of both domain-general and discipline-specific knowledge and reasoning strategies. In this study we investigated the implicit assumptions and modes of reasoning applied by individuals with…

  20. 77 FR 70189 - Manufacturer of Controlled Substances; Notice of Registration; Cayman Chemical Company

    Science.gov (United States)

    2012-11-23

    ... Company By Notice dated July 30, 2012, and published in the Federal Register on August 7, 2012, 77 FR... diethylamide (7315) I 2,5-Dimethoxy-4-(n)- I propylthiophenethylamine (7348). Marihuana (7360) I... (1105) II Lisdexamfetamine (1205) II The company plans to manufacture small quantities of...

  1. Influence of chosen microbes and some chemical substances on the production of aflatoxins

    Directory of Open Access Journals (Sweden)

    Iveta Brožková

    2015-03-01

    Full Text Available Aflatoxins are produced as secondary metabolites by A. flavus, A. parasiticus, A. nomius and A. tamarii. The aflatoxin biosynthetic pathway involves several enzymatic steps and genes (apa-2, ver-1 that appear to be regulated by the aflR gene in these fungi. The aim of this work was the detection of aflatoxins by the HPLC method and the ascertainment of factors influencing their production. A. parasiticus CCM F-108, A. parasiticus CCF 141, A. parasiticus CCF 3137 and two isolates A. flavus were used. These toxigenic isolates were recovered from spice (strain 1 and wraps (strain 2. The gene for the production of aflatoxin B1 for each species of fungi was detected using an optimized PCR method. Rhodotorula spp.*, Lactococcus lactis subsp. lactis CCM 1881, Flavobacterium spp. and fungal strain Pythium oligandrum* were tested for inhibition of aflatoxins production and fungal growth. Having used the HPLC detection, various preservatives (propionic acid, citric acid, potassium sorbate were tested from the viewpoint of their influence on the growth of aflatoxigenic fungi followed by the production of aflatoxins. The growth of A. flavus and A. parasiticus and aflatoxin production in Potato Dextrose Agar supplemented with propionic acid (1000-2000-3000 mg/kg, citric acid (2000-3000-4000 mg/kg and potassium sorbate (500-800-1000 mg/kg was tested by Agar Dilution Method. After 72 h of incubation was evaluated growth of fungi, all samples were frozen for later extraction and aflatoxins quantification by HPLC. Effect of peptone and sucrose additions were studied in yeast extract (2% supplemented with peptone (5-10-15% or sucrose (15%. Growth inhibition of Aspergillus by Pythium oligandrum was tested on wood surface. As shown, the highest inhibition effect on the aflatoxins production was obtained when propionic acid was applied in concentrations since 1000 mg/kg. A total inhibition of the fungi growth and aflatoxins production was observed in all samples

  2. A Cytogenetic Footprint for Mammary Carcinomas Induced by PhIP in Rats

    Energy Technology Data Exchange (ETDEWEB)

    Christian, A T

    2001-04-01

    PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine), a mutagen/carcinogen belonging to the class of heterocyclic amines (HCAs) found in cooked meats, is a mammary gland carcinogen in rats and has been implicated in the etiology of certain human cancers including breast cancer. To gain insight into the genomic alterations associated with PhIP-induced mammary gland carcinogenesis, we used comparative genomic hybridization (CGH) to examine chromosomal abnormalities in rat mammary carcinomas induced by PhIP, and for comparison, by DMBA (7,12-dimethylbenz[a]anthracene), a potent experimental mammary carcinogen. There was a consistent and characteristic pattern of chromosome-region loss in PhIP-induced carcinomas that clearly distinguished them from carcinomas induced by DMBA.

  3. The physico-chemical properties and biostimulative activities of humic substances regenerated from lignite

    OpenAIRE

    David, Jan; Šmejkalová, Daniela; Hudecová, Šárka; Zmeškal, Oldřich; von Wandruszka, Ray; Gregor, Tomáš; Kučerík, Jiří

    2014-01-01

    The positive effect of humic acids on the growth of plant roots is well known, however, the mechanisms and role of their physical structure in these processes have not been fully explained yet. In this work, South-Moravian lignite was oxidized by means of nitric acid and hydrogen peroxide to produce a set of regenerated humic acids. The elemental composition, solid state stability and solution characteristics were determined and correlated in vitro with their biological activity. A modified h...

  4. Complexation of transuranic ions by humic substances: Application of laboratory results to the natural system

    International Nuclear Information System (INIS)

    Environmental investigations show transuranic ions sorb to humic substances. The resulting species are often mobile and are expected to be important vectors in the migration of transuranic ions in natural systems. However, these environmental studies yield no quantitative data useful for modeling. Laboratory complexation experiments with transuranic ions and humic substances generate thermodynamic data required for complexation modeling. The data presented in this work are based on the metal ion charge neutralization model, which is briefly described. When a consistent complexation model is used, similar results are obtained from different experimental conditions, techniques, and laboratories. Trivalent transuranic ions (Cm(III), Am(III)) have been extensively studied with respect to pH, ionic strength, origin of humic acid, and mixed species formation. The complexation of Np(V) has been examined over a large pH and metal ion concentration range with different humic acids. Some data does exist on the complexation ion concentration range with different humic acids. Some data does exist on the complexation of plutonium with humic acid, however further work is needed. Calculations on the Gorleben aquifer system using the thermodynamic data are presented. Critical information lacking from the thermodynamic database is identified. 55 refs., 2 figs., 3 tabs

  5. Local sensing of biological substances by scanning electrochemical microscopy; Sosagata denki kagaku kenbikyo ni yoru seitai busshitsu no kyokusho sensing

    Energy Technology Data Exchange (ETDEWEB)

    Saito, T. [Tokyo College of Pharmacy, Tokyo (Japan)

    1999-01-01

    This paper describes a method for local detection of biological substances by using a scanning electrochemical microscope (SECM). The electrochemical detection method is a multipurpose analysis method that can quantify substances in aqueous solution on a real time basis. A micro electrode has made a debut recently and become applied to local zones in biological structures and cells. Capturing surface structures and compositions of substances have become possible with the SECM using the micro electrode as a probe, as does the probe of a scanning tunnel electron microscope (STM). While the STM can recognize microfine structures of smaller than 1 nm, the SECM does it only on {mu} level, but can measure a variety of living organisms as the recognition is possible in aqueous solutions. Antigens are reacted with antibodies on spots of several ten {mu} m oriented on a glass substrate, where oxidizing and reducing reactions by peroxidaze modified on the antibodies are read on the SECM, making quantification of the antibodies possible. Chemical treatment of enzymes and antibodies can also be performed onto the glass substrate by using this micro electrode. Expectation is placed on providing living organism information in multi items and multi dimensions. (NEDO)

  6. Entrapment of glucoamylase by sol-gel technique in PhTES/TEOS hybrid matrixes

    Directory of Open Access Journals (Sweden)

    B. Vlad-Oros

    2007-12-01

    Full Text Available Mesoporous silica particles were prepared by the sol-gel method from different alkoxysilane precursors and used as a host matrix for encapsulation of glucoamylase, an enzyme widely used in fermentative industry. The aim was to investigate the physico-chemical properties of the different silica powders and their effect on the enzyme kinetics. The encapsulated enzymes followed Michaelis-Menten kinetics. The Michaelis constant (KM and the maximum rate of starch hydrolysis reaction (Vmax were calculated according to the Michaelis-Menten and Lineweaver-Burke plots. The values of the Michaelis constant (KM of the encapsulated enzymes were higher than those of the free enzyme. The temperature and pH infl uence on the activity of free and immobilized glucoamylase were also compared. The results of this study show that the enzymes immobilized in organic/inorganic hybrid silica matrixes (obtained by the sol-gel method, allowing the entrapped glucoamylase to retain its biological activity, are suitable for many different applications, (medicinal, clinical, analytical.

  7. Effect of pH on DNA alkylation by enzyme-activated mitomycin C and porfiromycin.

    Science.gov (United States)

    Yu, F; Pan, S S

    1993-06-01

    DNA adduct formation by enzyme-activated antibiotics, mitomycin C (MMC) or porfiromycin (PFM), at pH 7.6 or pH 6.0 under anaerobic conditions was analyzed by a 32P-postlabeling method. Antibiotic activation by rat liver NADPH-cytochrome P-450 reductase (EC 1.6.2.4) and bovine milk xanthine oxidase (EC 1.2.3.2) produced similar results. Five 32P-labeled MMC adducts were separated by thin layer chromatography and high performance liquid chromatography from DNA alkylated at either pH. Four of the radioactive spots separated by thin layer chromatography were identified as two monofunctional monoadducts [1" alpha and 1" beta forms of N2-(2" beta,7"-diaminomitosen-1"-yl)-2'-deoxyguanylic acid], one bifunctional monoadduct [N2-(10"-decarbamoyl-2",7"-diaminomitosen-1" alpha-yl)-2'-deoxyguanylic acid], and one cross-linked adduct [N2-(2" beta,7"-diamino-10"-deoxyguanyl-N2-yl-mitosen- 1" alpha-yl)-2'-deoxyguanylic acid]. One minor radioactive spot was not identified. By comparing DNA alkylated at the two pH values, based on equal amounts of 32P radioactivity, similar amounts of cross-links were detected. However, the DNA showed different ratios of the alpha and beta isomers of the monofunctional monoadduct. Furthermore, the DNA alkylated at pH 6.0 showed more bifunctional monoadducts than did the DNA alkylated at pH 7.6. Analysis of alkylated DNA by enzyme-activated PFM showed a similar spectrum of DNA adduct formation. The effect of pH on the distribution of the five PFM-DNA adducts was similar to that observed for the five MMC-DNA adducts. The distribution of adducts in DNA alkylated at the same pH was similar irrespective of which enzyme activated MMC or PFM. The pH of the reaction during DNA and MMC interaction was the determining factor for the quantitative distribution of the adducts. This pH effect may be important for the cytotoxicity of MMC and PFM in tumor cells that have high levels of reductive enzymes with low optimal pH values. PMID:8391116

  8. Mechanisms of soil pH regulation by biochar amendments and consequences for biochar long-term effects

    OpenAIRE

    Rees, Frédéric; Morel, Jean-Louis

    2015-01-01

    Soil amendments of biochar, i.e. the solid product of biomass pyrolysis, have been increasingly investigated over the last few years as a way to store stable C in soils, to improve crop production and to remediate degraded and contaminated land. Many short-term effects of biochar on soil chemical and biological properties may be explained by the observed increase of soil pH, largely reported in the recent scientific literature for acid or neutral soils. However, both the mechanisms by which b...

  9. Enhanced production of 2,3-butanediol from glycerol by forced pH fluctuations.

    Science.gov (United States)

    Petrov, Kaloyan; Petrova, Penka

    2010-07-01

    The glycerol fermentation by Klebsiella pneumoniae occurs by receiving more than five liquid products-organic acids, diols, and ethanol. Aiming to direct the glycerol conversion towards predominant production of 2,3-butanediol (2,3-BD), the main influencing parameters (the aeration and the pH) were investigated during fed-batch processes. The regime of intensive aeration (2.2 vvm air supply) was evaluated as most favorable for 2,3-BD synthesis and ensured the decrease of all other metabolites. Thus, without pH control, 52.5 g/l 2,3-BD were produced, as the carbon conversion of glycerol into 2,3-BD reached 60.6%. Additional enhancement in 2,3-BD production (by significant increase of glycerol utilization) was achieved by the development of a new method of "forced pH fluctuations". It was realized by consecutive raisings of pH using definite DeltapH value, at exact time intervals, allowing multiple variations. Thus, the optimal conditions for maximal glycerol consumption were defined, and 70 g/l 2,3-BD were produced, which is the highest amount obtained from glycerol as a sole carbon source until now. The forced pH fluctuations emphasized pH as a governing factor in microbial conversion processes. PMID:20361325

  10. The physical-chemical properties of substance of the bright fireball EN171101 Turyi Remety

    Science.gov (United States)

    Churyumov, Klim; Belevtsev, Rudolf; Sobotovich, Emlen; Spivak, Svitlana; Churyumova, Tetyana

    2015-03-01

    In 2007-2011 searches were conducted for mineralogical and geochemical studies of the soil in the region of fall down of a bright fireball EN171101 ``Turyi Remety`` matter in Perechyn district of Transcarpathian. In the assumed location of the fall of a meteorite material for analysis was taken from the bottom of streams of Transcarpathian Mountains. In this matter we have been found numerous small magnetic spheres (microspherul) and fused segments, which have enough large sizes - up to 5 mm in diameter, which probably are fragments of the Turyi Remety meteoroid. One of the known signs of fireballs are sand-sized magnetic balls (by diameter 0.1-1.0 mm), which are often found in the magnetic concentrate fraction. This small balls, together with fragments of fused iotsit (FeO) are formed during the ablation of the meteoroid, and their sizes decreases during the motion of the meteoroid in the Earths atmosphere. From the east to the west, the radius of the balls in the study area decreased from an average of 0.7-0.5 mm to 0.1-0.3 mm. The sizes of such balls, as glowing molten particles of the meteoroid, are in good agreement with calculations based on the energy loss of the Turyi Remety meteoroid. This confirms the cosmic origin of these found small balls. Pre-calculated physical parameters of the Turyi Remety meteoroid are the velocity, mass, kinetic energy, the resistance force during ablation, the average fireball particle radius along trajectory path of a meteoroid fragments depending from the mass and size. Rapid mass loss of the meteoroid in more than 10 times, stronger, shorter ablation and damping fireball at the high altitude say about instability and the participation of the meteoroid gas in ablation. Perhaps the presence of ice, and other fireball gases in the meteoroid composition shows that its composition was close to comet one or to a chondrite with ice (gas hydrates). Especially likely gaseous hydrates of heavy gases such as CO2, H2S, hydrocarbons

  11. Internal Active Thermal Control System (IATCS) Sodium Bicarbonate/Carbonate Buffer in an Open Aqueous Carbon Dioxide System and Corollary Electrochemical/Chemical Reactions Relative to System pH Changes

    Science.gov (United States)

    Stegman, Thomas W.; Wilson, Mark E.; Glasscock, Brad; Holt, Mike

    2014-01-01

    The International Space Station (ISS) Internal Active Thermal Control System (IATCS) experienced a number of chemical changes driven by system absorption of CO2 which altered the coolant’s pH. The natural effects of the decrease in pH from approximately 9.2 to less than 8.4 had immediate consequences on system corrosion rates and corrosion product interactions with specified coolant constituents. The alkalinity of the system was increased through the development and implementation of a carbonate/bicarbonate buffer that would increase coolant pH to 9.0 – 10.0 and maintain pH above 9.0 in the presence of ISS cabin concentrations of CO2 up to twenty times higher than ground concentrations. This paper defines how a carbonate/bicarbonate buffer works in an open carbon dioxide system and summarizes the analyses performed on the buffer for safe and effective application in the on-orbit system. The importance of the relationship between the cabin environment and the IATCS is demonstrated as the dominant factor in understanding the system chemistry and pH trends before and after addition of the carbonate/bicarbonate buffer. The paper also documents the corollary electrochemical and chemical reactions the system has experienced and the rationale for remediation of these effects with the addition of the carbonate/bicarbonate buffer.

  12. Detection of irradiated peppers by viscosity measurement at extremely high pH

    International Nuclear Information System (INIS)

    The viscosities of aqueous suspensions of irradiated peppers determined after heat gelatinization were influenced by the pH of the suspension to a greater degree than those of unirradiated ones. Viscosity measurement under an extremely alkaline condition (pH 13.8) resulted in a significant different between irradiated peppers and unirradiated ones, irrespective of the planting locality and storage period. All of the pepper samples irradiated at 5 kGy showed viscosity values significantly lower than unirradiated ones. (Author)

  13. Effect of pH on the structure and drug release profiles of layer-by-layer assembled films containing polyelectrolyte, micelles, and graphene oxide

    Science.gov (United States)

    Han, Uiyoung; Seo, Younghye; Hong, Jinkee

    2016-01-01

    Layer by layer (lbl) assembled multilayer thin films are used in drug delivery systems with attractive advantages such as unlimited selection of building blocks and free modification of the film structure. In this paper, we report the fundamental properties of lbl films constructed from different substances such as PS-b-PAA amphiphilic block copolymer micelles (BCM) as nano-sized drug vehicles, 2D-shaped graphene oxide (GO), and branched polyethylenimine (bPEI). These films were fabricated by successive lbl assembly as a result of electrostatic interactions between the carboxyl group of BCM and amine group of functionalized GO or bPEI under various pH conditions. We also compared the thickness, roughness, morphology and degree of adsorption of the (bPEI/BCM) films to those in the (GO/BCM) films. The results showed significant difference because of the distinct pH dependence of each material. In addition, drug release rates of the GO/BCM film were more rapid those of the (bPEI/BCM) film in pH 7.4 and pH 2 PBS buffer solutions. In (bPEI/BCM/GO/BCM) film, the inserted GO layers into bPEI/BCM multilayer induced rapid drug release. We believe that these materials & pH dependent film properties allow developments in the control of coating techniques for biological and biomedical applications. PMID:27052827

  14. Effect of pH on the structure and drug release profiles of layer-by-layer assembled films containing polyelectrolyte, micelles, and graphene oxide

    Science.gov (United States)

    Han, Uiyoung; Seo, Younghye; Hong, Jinkee

    2016-04-01

    Layer by layer (lbl) assembled multilayer thin films are used in drug delivery systems with attractive advantages such as unlimited selection of building blocks and free modification of the film structure. In this paper, we report the fundamental properties of lbl films constructed from different substances such as PS-b-PAA amphiphilic block copolymer micelles (BCM) as nano-sized drug vehicles, 2D-shaped graphene oxide (GO), and branched polyethylenimine (bPEI). These films were fabricated by successive lbl assembly as a result of electrostatic interactions between the carboxyl group of BCM and amine group of functionalized GO or bPEI under various pH conditions. We also compared the thickness, roughness, morphology and degree of adsorption of the (bPEI/BCM) films to those in the (GO/BCM) films. The results showed significant difference because of the distinct pH dependence of each material. In addition, drug release rates of the GO/BCM film were more rapid those of the (bPEI/BCM) film in pH 7.4 and pH 2 PBS buffer solutions. In (bPEI/BCM/GO/BCM) film, the inserted GO layers into bPEI/BCM multilayer induced rapid drug release. We believe that these materials & pH dependent film properties allow developments in the control of coating techniques for biological and biomedical applications.

  15. Production and characterization of a bacteriocin-like inhibitory substance produced by indigenous soil associated pseudomonas putida mas-1

    International Nuclear Information System (INIS)

    Bacteriocins have been the subject of extensive research globally due to wide range applications. The aim of this research was to investigate the production of bacteriocin(s) or bacteriocin like inhibitory substance(s) by Pseudomonas putida MAS-1 strain. The bacteriocin produced (Putidacin MAS-1) was found bioactive against clinical Staphylococcus aureus and Enterococcus faecalis strains. Bioactivity was observed by stab and overlay assay and multiwell antagonistic activity assay. Putidacin MAS-1 was sensitive beyond 70 degree C but stable at wide pH range (3 to 8). Bioactivity of putidacin MAS-1 was lost after treatment with trypsin and protease while partially lost after Proteinase K treatment. Treatment with ethanol, methanol, chloroform, acetone Tween 20 and Tween 80 showed partial decrease in bioactivity. SDS had stimulatory effect on putidacin MAS-1 bioactivity. EDTA however, showed no effect on the bacteriocin bioactivity. It was partially purified by ammonium sulphate precipitation. SDS-PAGE showed that Putidacin MAS-1 had 15 kDa molecular weight. (author)

  16. Aqueous speciation and pH effect on the sorption behavior of uranium by montmorillonite

    International Nuclear Information System (INIS)

    Clay minerals occur widely in nature and play a very important role in agriculture, mineral recovery and chemical manufacturing. Among the many properties which affect clay behaviour, water binding and ion exchanging appear to be the most important. The study of the cation exchange capacity of soils is of great theoretical and practical importance since the CEC determines in many ways the behavior of nutrients, chemical amendments, and many toxic compounds entering the soils. Sorption interactions with montmorillonite and other clay minerals in soils are potentially important mechanisms for attenuating the mobility of heavy metal cations through the subsurface environment. In this work the cation exchange capacity (CEC) of montmorillonite from west Anatolia, and sorptions interactions with montmorillonite for attenuating the mobility of uranium were studied. The CEC value was found to be 77 meq/100 g montmorillonite. The relative importance of test parameters e.g., contact time, particle size, pH and U(+6) aqueous speciation was determined. The results show that sorption on montmorillonite is a function of pH depending strongly on the aqueous U(+6) species. It reaches a maximum at near neutral pH(pH∼7). At low and at high pH solutions the sorption values of uranium are poor. These sorption values were attributed to the formation of aqueous U(+6) carbonate complexes in alkaline conditions and the ion-exchange process between UO2+2 species and interlayer cations on montmorillonite in acidic solutions. (author)

  17. Role of pH on antioxidants production by Spirulina (Arthrospira platensis

    Directory of Open Access Journals (Sweden)

    Mostafa Mahmoud Sami Ismaiel

    2016-06-01

    Full Text Available Abstract Algae can tolerate a broad range of growing conditions but extreme conditions may lead to the generation of highly dangerous reactive oxygen species (ROS, which may cause the deterioration of cell metabolism and damage cellular components. The antioxidants produced by algae alleviate the harmful effects of ROS. While the enhancement of antioxidant production in blue green algae under stress has been reported, the antioxidant response to changes in pH levels requires further investigation. This study presents the effect of pH changes on the antioxidant activity and productivity of the blue green alga Spirulina (Arthrospira platensis. The algal dry weight (DW was greatly enhanced at pH 9.0. The highest content of chlorophyll a and carotenoids (10.6 and 2.4 mg/g DW, respectively was recorded at pH 8.5. The highest phenolic content (12.1 mg gallic acid equivalent (GAE/g DW was recorded at pH 9.5. The maximum production of total phycobiliprotein (159 mg/g DW was obtained at pH 9.0. The antioxidant activities of radical scavenging activity, reducing power and chelating activity were highest at pH 9.0 with an increase of 567, 250 and 206% compared to the positive control, respectively. Variation in the activity of the antioxidant enzymes superoxide dismutase (SOD, catalase (CAT and peroxidase (POD was also reported. While the high alkaline pH may favor the overproduction of antioxidants, normal cell metabolism and membrane function is unaffected, as shown by growth and chlorophyll content, which suggests that these conditions are suitable for further studies on the harvest of antioxidants from S. platensis.

  18. Role of pH on antioxidants production by Spirulina (Arthrospira) platensis.

    Science.gov (United States)

    Ismaiel, Mostafa Mahmoud Sami; El-Ayouty, Yassin Mahmoud; Piercey-Normore, Michele

    2016-01-01

    Algae can tolerate a broad range of growing conditions but extreme conditions may lead to the generation of highly dangerous reactive oxygen species (ROS), which may cause the deterioration of cell metabolism and damage cellular components. The antioxidants produced by algae alleviate the harmful effects of ROS. While the enhancement of antioxidant production in blue green algae under stress has been reported, the antioxidant response to changes in pH levels requires further investigation. This study presents the effect of pH changes on the antioxidant activity and productivity of the blue green alga Spirulina (Arthrospira) platensis. The algal dry weight (DW) was greatly enhanced at pH 9.0. The highest content of chlorophyll a and carotenoids (10.6 and 2.4mg/g DW, respectively) was recorded at pH 8.5. The highest phenolic content (12.1mg gallic acid equivalent (GAE)/g DW) was recorded at pH 9.5. The maximum production of total phycobiliprotein (159mg/g DW) was obtained at pH 9.0. The antioxidant activities of radical scavenging activity, reducing power and chelating activity were highest at pH 9.0 with an increase of 567, 250 and 206% compared to the positive control, respectively. Variation in the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) was also reported. While the high alkaline pH may favor the overproduction of antioxidants, normal cell metabolism and membrane function is unaffected, as shown by growth and chlorophyll content, which suggests that these conditions are suitable for further studies on the harvest of antioxidants from S. platensis. PMID:26991300

  19. Effect of initial pH in levan production by Zymomonas mobilis immobilized in sodium alginate

    Directory of Open Access Journals (Sweden)

    Vidiany Aparecida Queiroz Santos

    2014-04-01

    Full Text Available Zymomonas mobilis was immobilized using a cell suspension fixed to 8.6 x 107 CFU mL-1 by spectrophotometry. This biomass was suspended in sodium alginate solution (3% that was dropped with a hypodermic syringe into 0.2 M calcium chloride solution. Was test two initial pH of fermentation medium (4 and 5 and different sucrose concentrations 15, 20, 25, 30 and 35% at 30˚C, without stirring for 24, 48, 72 and 96 hours. The levan production to pH 4 was high in sucrose 25% for 24 (16.51 g L-1 and 48 (15.31 g L-1 hours. The best values obtained to pH 5 was in sucrose 35% during 48 (22.39 g L-1 and 96 (23.5 g L-1 hours, respectively. The maximum levan yield was 40.8% and 22.47% in sucrose 15% to pH 4 and 5, respectively. Substrate consumption to pH 4 was bigger in sucrose 15 (56.4% and 20% (59.4% and to pH 5 was in 25 (68.85% and 35% (64.64%. In relation to immobilization efficiency, Zymomonas mobilis showed high adhesion and colonization in support, indicated by cell growth increased from 107 to 109 CFU mL-1 during fermentation time.

  20. Human immunodeficiency virus-1 protease. 2. Use of pH rate studies and solvent kinetic isotope effects to elucidate details of chemical mechanism.

    Science.gov (United States)

    Hyland, L J; Tomaszek, T A; Meek, T D

    1991-08-27

    The pH dependence of the peptidolytic reaction of recombinant human immunodeficiency virus type 1 protease has been examined over a pH range of 3-7 for four oligopeptide substrates and two competitive inhibitors. The pK values obtained from the pKis vs pH profiles for the unprotonated and protonated active-site aspartyl groups, Asp-25 and Asp-25', in the monoprotonated enzyme form were 3.1 and 5.2, respectively. Profiles of log V/K vs pH for all four substrates were "bell-shaped" in which the pK values for the unprotonated and protonated aspartyl residues were 3.4-3.7 and 5.5-6.5, respectively. Profiles of log V vs pH for these substrates were "wave-shaped" in which V was shifted to a constant lower value upon protonation of a residue of pK = 4.2-5.2. These results indicate that substrates bind only to a form of HIV-1 protease in which one of the two catalytic aspartyl residues is protonated. Solvent kinetic isotope effects were measured over a pH (D) range of 3-7 for two oligopeptide substrates, Ac-Arg-Ala-Ser-Gln-Asn-Tyr-Pro-Val-Val-NH2 and Ac-Ser-Gln-Asn-Tyr-Pro-Val-Val-NH2. The pH-independent value for DV/K was 1.0 for both substrates, and DV = 1.5-1.7 and 2.2-3.2 at low and high pH (D), respectively. The attentuation of both V and DV at low pH (D) is consistent with a change in rate-limiting step from a chemical one at high pH (D) to one in which a product release step or an enzyme isomerization step becomes partly rate-limiting at low pH (D). Proton inventory data is in accord with the concerted transfer of two protons in the transition state of a rate-limiting chemical step in which the enzyme-bound amide hydrate adduct collapses to form the carboxylic acid and amine products. PMID:1883831

  1. Regulation of dopamine D2 receptors by sodium and pH

    International Nuclear Information System (INIS)

    The role of Na+ and H+ in the regulation of D2 receptor affinity for ligands was studied to determine the molecular mechanisms of this phenomenon. The potency of substituted benzamide derivatives and agonists at D2 receptors depended on the concentration of Na+ and H+, whereas the potency of other antagonists was relatively unaltered by changes in pH or Na+ concentration. The potency of agonists was generally decreased in the presence of NaCl or lowered pH. For example, in the absence of sodium the affinity of D2 receptors for dopamine was decreased 17-fold by lowering of the pH from 8.0 to pH 6.8. Addition of NaCl caused 2-4-fold decreases in affinity for most agonists. The affinity of the receptors for two substituted benzamide derivatives, on the other hand, was reduced 6-44-fold by elevated concentrations of H+ but was enhanced 7-24-fold in the presence of Na+. The regulation by H+ of the potency of dopamine was selective for D2 receptors, because binding of dopamine to neostriatal D1 receptors was unaffected by changes in pH. Decreasing of the pH from 8.0 or 7.3 to 6.8 facilitated the dissociation of the substituted benzamide ligand 125I epidepride from D2 receptors but inhibited dissociation of 3H spiperone. Furthermore, the presence of NaCl or lowered pH slowed inactivation of D2 receptors by N-ethylmaleimide. Together, these data suggest that the conformation of D2 receptors is regulated by both Na+ and H+. The affinity of D2 receptors for agonists and substituted benzamide antagonists varies according to the conformational state of the receptors, whereas other antagonists bind to both forms with approximately equal potency. Amiloride is a compound that interacts with many sodium-binding macromolecules

  2. Regulation of dopamine D2 receptors by sodium and pH

    Energy Technology Data Exchange (ETDEWEB)

    Neve, K.A. (VA Medical Center, Portland, OR (USA))

    1991-04-01

    The role of Na+ and H+ in the regulation of D2 receptor affinity for ligands was studied to determine the molecular mechanisms of this phenomenon. The potency of substituted benzamide derivatives and agonists at D2 receptors depended on the concentration of Na+ and H+, whereas the potency of other antagonists was relatively unaltered by changes in pH or Na+ concentration. The potency of agonists was generally decreased in the presence of NaCl or lowered pH. For example, in the absence of sodium the affinity of D2 receptors for dopamine was decreased 17-fold by lowering of the pH from 8.0 to pH 6.8. Addition of NaCl caused 2-4-fold decreases in affinity for most agonists. The affinity of the receptors for two substituted benzamide derivatives, on the other hand, was reduced 6-44-fold by elevated concentrations of H+ but was enhanced 7-24-fold in the presence of Na+. The regulation by H+ of the potency of dopamine was selective for D2 receptors, because binding of dopamine to neostriatal D1 receptors was unaffected by changes in pH. Decreasing of the pH from 8.0 or 7.3 to 6.8 facilitated the dissociation of the substituted benzamide ligand {sup 125}I epidepride from D2 receptors but inhibited dissociation of {sup 3}H spiperone. Furthermore, the presence of NaCl or lowered pH slowed inactivation of D2 receptors by N-ethylmaleimide. Together, these data suggest that the conformation of D2 receptors is regulated by both Na+ and H+. The affinity of D2 receptors for agonists and substituted benzamide antagonists varies according to the conformational state of the receptors, whereas other antagonists bind to both forms with approximately equal potency. Amiloride is a compound that interacts with many sodium-binding macromolecules.

  3. Considering evidence: The approach taken by the Hazardous Substances Advisory Committee in the UK.

    Science.gov (United States)

    Collins, Chris D; Baddeley, Michelle; Clare, Gill; Murphy, Richard; Owens, Susan; Rocks, Sophie

    2016-01-01

    The Hazardous Substances Advisory Committee (HSAC) provides expert advice to UK officials, Ministers and other relevant bodies on the protection of the environment, and human health via the environment, from potentially hazardous substances and articles. Hazardous substances are often the subject of controversy, on which individuals, and different groups in society, hold divergent views. This paper details the approach taken by HSAC when considering the evidence to provide advice on hazardous substances. Firstly HSAC reviews the range of evidence and determines its quality considering: transparency of aims, the methodology and results, completeness, independent review and accessibility. HSAC does not follow one explicit methodology as the wide range of hazardous substances we consider means they need to be addressed on a case by case basis. Most notably HSAC considers the evidence in the wider context, being aware of factors that influence individuals in their decision making when receiving a HSAC opinion e.g. trust in the source of the evidence, defensibility, conformity to a 'world view' and framing. HSACs also reflect on its own perspectives with the aim of addressing bias by the diversity of its membership. The Committee's intention, in adopting this rounded approach, is to reach opinions that are robust, relevant and defensible. PMID:27106133

  4. Stimulation of phosphoinositide hydrolysis by a novel substance partially purified from rat and bovine brain

    International Nuclear Information System (INIS)

    This study demonstrates the partial purification of a potentially novel substance from rat and bovine brain. Whole brains were homogenized in distilled water, then heated at 1000C for 30 min. The water extract was dialyzed and the 3H-inositol monophosphate (3H-IP) using lithium-treated slices of rat cerebral cortex prelabelled with 3H-myo-inositol. A major peak of activity was observed in fractions from the molecular weight range of 800-1300 daltons. Stimulation of phosphoinositide hydrolysis by this material was time-dependent and dose-related. Maximal stimulation of 3H-IP (323% of control) required 10mg/ml of bovine material and was observed at 30 minutes. These effects could not be mimicked by a number of substances of similar molecular weight (e.g. substance P, neurotensin, angiotensin II, bradykinin). Furthermore, the effects of this material were not blocked by antagonist drugs which act at the alpha-adrenoceptor, muscarinic cholinoceptor, 5-HT2 receptor, substance P receptor, or neurotensin receptor. These results indicate that the substance isolated may be a novel neuroactive molecule which has receptors coupled to phosphoinositide hydrolysis in brain

  5. Non-monotonic swelling of surface grafted hydrogels induced by pH and/or salt concentration

    Science.gov (United States)

    Longo, Gabriel S.; Olvera de la Cruz, Monica; Szleifer, I.

    2014-09-01

    We use a molecular theory to study the thermodynamics of a weak-polyacid hydrogel film that is chemically grafted to a solid surface. We investigate the response of the material to changes in the pH and salt concentration of the buffer solution. Our results show that the pH-triggered swelling of the hydrogel film has a non-monotonic dependence on the acidity of the bath solution. At most salt concentrations, the thickness of the hydrogel film presents a maximum when the pH of the solution is increased from acidic values. The quantitative details of such swelling behavior, which is not observed when the film is physically deposited on the surface, depend on the molecular architecture of the polymer network. This swelling-deswelling transition is the consequence of the complex interplay between the chemical free energy (acid-base equilibrium), the electrostatic repulsions between charged monomers, which are both modulated by the absorption of ions, and the ability of the polymer network to regulate charge and control its volume (molecular organization). In the absence of such competition, for example, for high salt concentrations, the film swells monotonically with increasing pH. A deswelling-swelling transition is similarly predicted as a function of the salt concentration at intermediate pH values. This reentrant behavior, which is due to the coupling between charge regulation and the two opposing effects triggered by salt concentration (screening electrostatic interactions and charging/discharging the acid groups), is similar to that found in end-grafted weak polyelectrolyte layers. Understanding how to control the response of the material to different stimuli, in terms of its molecular structure and local chemical composition, can help the targeted design of applications with extended functionality. We describe the response of the material to an applied pressure and an electric potential. We present profiles that outline the local chemical composition of the

  6. Non-monotonic swelling of surface grafted hydrogels induced by pH and/or salt concentration

    International Nuclear Information System (INIS)

    We use a molecular theory to study the thermodynamics of a weak-polyacid hydrogel film that is chemically grafted to a solid surface. We investigate the response of the material to changes in the pH and salt concentration of the buffer solution. Our results show that the pH-triggered swelling of the hydrogel film has a non-monotonic dependence on the acidity of the bath solution. At most salt concentrations, the thickness of the hydrogel film presents a maximum when the pH of the solution is increased from acidic values. The quantitative details of such swelling behavior, which is not observed when the film is physically deposited on the surface, depend on the molecular architecture of the polymer network. This swelling-deswelling transition is the consequence of the complex interplay between the chemical free energy (acid-base equilibrium), the electrostatic repulsions between charged monomers, which are both modulated by the absorption of ions, and the ability of the polymer network to regulate charge and control its volume (molecular organization). In the absence of such competition, for example, for high salt concentrations, the film swells monotonically with increasing pH. A deswelling-swelling transition is similarly predicted as a function of the salt concentration at intermediate pH values. This reentrant behavior, which is due to the coupling between charge regulation and the two opposing effects triggered by salt concentration (screening electrostatic interactions and charging/discharging the acid groups), is similar to that found in end-grafted weak polyelectrolyte layers. Understanding how to control the response of the material to different stimuli, in terms of its molecular structure and local chemical composition, can help the targeted design of applications with extended functionality. We describe the response of the material to an applied pressure and an electric potential. We present profiles that outline the local chemical composition of the

  7. Non-monotonic swelling of surface grafted hydrogels induced by pH and/or salt concentration

    Energy Technology Data Exchange (ETDEWEB)

    Longo, Gabriel S. [Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CONICET, La Plata (Argentina); Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Olvera de la Cruz, Monica [Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Szleifer, I., E-mail: igal@northwestern.edu [Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-09-28

    We use a molecular theory to study the thermodynamics of a weak-polyacid hydrogel film that is chemically grafted to a solid surface. We investigate the response of the material to changes in the pH and salt concentration of the buffer solution. Our results show that the pH-triggered swelling of the hydrogel film has a non-monotonic dependence on the acidity of the bath solution. At most salt concentrations, the thickness of the hydrogel film presents a maximum when the pH of the solution is increased from acidic values. The quantitative details of such swelling behavior, which is not observed when the film is physically deposited on the surface, depend on the molecular architecture of the polymer network. This swelling-deswelling transition is the consequence of the complex interplay between the chemical free energy (acid-base equilibrium), the electrostatic repulsions between charged monomers, which are both modulated by the absorption of ions, and the ability of the polymer network to regulate charge and control its volume (molecular organization). In the absence of such competition, for example, for high salt concentrations, the film swells monotonically with increasing pH. A deswelling-swelling transition is similarly predicted as a function of the salt concentration at intermediate pH values. This reentrant behavior, which is due to the coupling between charge regulation and the two opposing effects triggered by salt concentration (screening electrostatic interactions and charging/discharging the acid groups), is similar to that found in end-grafted weak polyelectrolyte layers. Understanding how to control the response of the material to different stimuli, in terms of its molecular structure and local chemical composition, can help the targeted design of applications with extended functionality. We describe the response of the material to an applied pressure and an electric potential. We present profiles that outline the local chemical composition of the

  8. Gastro-oesophageal reflux demonstrated by radiography: a supplement to 24-h pH monitoring

    International Nuclear Information System (INIS)

    Purpose: Gastro-oesophageal reflux (GOR) is demonstrated by radiography as a supplement to 24-h pH monitoring. Material and Methods: Forty-two patients (mean age 44 years) with suspicion of GOR disease were assessed according to a standard questionnaire. GOR was investigated by 24-h pH-monitoring and by radiography. Oesophageal emptying and the presence of rings or strictures were registered as well. Mucosal biopsies, classified as normal, light oesophagitis, severe oesophagitis, or Barrett's oesophagus, were correlated to age, gender, symptomatology, pH monitoring, and oesophageal emptying. GOR and morphological changes demonstrated by radiography were correlated to pH monitoring and mucosa biopsies. Results: Based on pH monitoring, patients with severe oesophagitis and Barrett's oesophagus had a significantly higher acid exposure compared to patients with normal mucosa and light oesophagitis, with no difference concerning age, gender, and symptoms. Severe oesophagitis, including Barrett's oesophagus, was found only in patients with a positive test for radiologic GOR. Eleven patients had rings or strictures independent of oesophageal mucosal changes. Conclusion: GOR demonstrated by radiography identified patients where complications could be expected, which was not possible by pH monitoring alone

  9. Gastro-oesophageal reflux demonstrated by radiography: a supplement to 24-h pH monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, E.; Aksglaede, K.; Jacobsen, N.O.; Funch-Jensen, P.; Thommesen, P. [Aarhus Univ. Hospital (Denmark)

    2001-09-01

    Purpose: Gastro-oesophageal reflux (GOR) is demonstrated by radiography as a supplement to 24-h pH monitoring. Material and Methods: Forty-two patients (mean age 44 years) with suspicion of GOR disease were assessed according to a standard questionnaire. GOR was investigated by 24-h pH-monitoring and by radiography. Oesophageal emptying and the presence of rings or strictures were registered as well. Mucosal biopsies, classified as normal, light oesophagitis, severe oesophagitis, or Barrett's oesophagus, were correlated to age, gender, symptomatology, pH monitoring, and oesophageal emptying. GOR and morphological changes demonstrated by radiography were correlated to pH monitoring and mucosa biopsies. Results: Based on pH monitoring, patients with severe oesophagitis and Barrett's oesophagus had a significantly higher acid exposure compared to patients with normal mucosa and light oesophagitis, with no difference concerning age, gender, and symptoms. Severe oesophagitis, including Barrett's oesophagus, was found only in patients with a positive test for radiologic GOR. Eleven patients had rings or strictures independent of oesophageal mucosal changes. Conclusion: GOR demonstrated by radiography identified patients where complications could be expected, which was not possible by pH monitoring alone.

  10. Acetate biodegradation by anaerobic microorganisms at high pH and high calcium concentration

    International Nuclear Information System (INIS)

    Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14C compounds in cementitious repositories. Tamagawa river sediment or Teganuma pond sediment was anaerobically cultured with 5 mM acetate and 10 mM nitrate at pH 9.5-12 at 30 oC. After 20 and 90 days, the acetate concentration of the culture medium was analyzed and found to have decreased below 5 mM at pH ≤ 11. On the other hand, it did not decrease when either sediment was incubated in the absence of nitrate. These results suggest that nitrate-reducing bacteria can biodegrade acetate under more alkaline conditions than the reported pH range in which nitrate-reducing bacteria can exhibit activity. Acetate biodegradation was also examined at a high calcium concentration. Sediments were anaerobically cultured at pH 9.5 with 5 mM acetate and 10 mM nitrate in solution, equilibrated with ordinary Portland cement hydrate, in which the Ca concentration was 14.6 mM. No decrease in acetate concentration after incubation of the sediments was observed, nor was it lower than in the absence of cementitious composition, suggesting that kinetics of acetate biodegradation by anaerobic microorganisms is lowered by a high Ca concentration. - Research highlights: → Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14C compounds in cementitious repositories. → Nitrate-reducing bacteria can biodegrade acetate at pH ≤ 11. → Kinetics of acetate biodegradation by anaerobic microorganisms might be lowered by a high Ca concentration.

  11. Chemical analysis by nuclear techniques

    International Nuclear Information System (INIS)

    This state art report consists of four parts, production of micro-particles, analysis of boron, alpha tracking method and development of neutron induced prompt gamma ray spectroscopy (NIPS) system. The various methods for the production of micro-paticles such as mechanical method, electrolysis method, chemical method, spray method were described in the first part. The second part contains sample treatment, separation and concentration, analytical method, and application of boron analysis. The third part contains characteristics of alpha track, track dectectors, pretreatment of sample, neutron irradiation, etching conditions for various detectors, observation of track on the detector, etc. The last part contains basic theory, neutron source, collimator, neutron shields, calibration of NIPS, and application of NIPS system

  12. Influence of impregnation by inorganic substances on the yield of pyrolysis products

    Energy Technology Data Exchange (ETDEWEB)

    Shevkoplyas, V.N.; Saranchuk, V.I. [AN Ukrainskoj SSR, Donetsk (Ukraine). Inst. Fiziko-Organicheskoj Khimii i Uglekhimii

    1998-09-01

    In papers was shown that fossil coals impregnation by aqueous solution of inorganic substances with a subsequent pyrolysis leads to the rise of the rate and depth of its organic mass destruction into liquid and gaseous products. This is, apperently, conditioned by changes in coals structure already on the stage of treatment. But, there are few papers that study an activating effect of inorganic reactants upon natural coals structure and their behaviour at pyrolysis. One of the methods which allows to judge structural transformation in coals at their impregnation by inorganic substances is an X-ray analysis. (orig.)

  13. Comparison of Antibiotic Resistance Removal Efficiencies Using Ozone Disinfection under Different pH and Suspended Solids and Humic Substance Concentrations.

    Science.gov (United States)

    Pak, Gijung; Salcedo, Dennis Espineli; Lee, Hansaem; Oh, Junsik; Maeng, Sung Kyu; Song, Kyung Guen; Hong, Seok Won; Kim, Hyun-Chul; Chandran, Kartik; Kim, Sungpyo

    2016-07-19

    This study mainly evaluated the effectiveness of ozonation toward the enhancement of the removal efficiencies of antibiotic-resistant bacteria (ARB), pB10 plasmid transfer, and pB10 plasmids under different pH and suspended solids (SS) and humic acid concentrations. First, chlorination was tested as a reference disinfection process. Chlorination at a very high dose concentration of Cl2 (75 mg L(-1)) and a long contact time (10 min) were required to achieve approximately 90% ARB and pB10 plasmid transfer removal efficiencies. However, even these stringent conditions only resulted in a 78.8% reduction of pB10 plasmid concentrations. In case of ozonation, the estimated CT (concentration × contact time) value (at C0 = 7 mg L(-1)) for achieving 4-log pB10 plasmid removal efficiency was 127.15 mg·min L(-1), which was 1.04- and 1.25-fold higher than those required for ARB (122.73 mg·min L(-1)) and a model nonantibiotic resistant bacterial strain, E. coli K-12, (101.4 mg·min L(-1)), respectively. In preventing pB10 plasmid transfer, ozonation achieved better performance under conditions of higher concentrations of humic acid and lower pH. Our study results demonstrated that the applicability of CT concept in practice, conventionally used for disinfection, might not be appropriate for antibiotic resistance control in the wastewater treatment process. Further studies should be conducted in wastewater engineering on how to implement multiple barriers including disinfection to prevent ARB and ARG discharge into the environment. PMID:27389869

  14. Water quality improvement of a lagoon containing mixed chemical industrial wastewater by micro-electrolysis-contact oxidization

    Institute of Scientific and Technical Information of China (English)

    Ya-fei ZHOU; Mao LIU; Qiong WU

    2011-01-01

    A lagoon in the New Binhai District, a high-speed developing area, Tianjin, China, has long been receiving the mixed chemical industrial wastewater from a chemical industrial park. This lagoon contained complex hazardous substances such as heavy metals and accumulative pollutants which stayed over time with a poor biodegradability. According to the characteristics of wastewater in the lagoon, the micro-electrolysis process was applied to improve the biodegradability before the bioprocess treatment. By the orthogonal experimental study of main factors influencing the efficiency of the treatment method, the best control parameters were obtained, including pH=2.0, a volume ratio of Fe and reaction wastewater of 0.03750, a volume ratio of Fe and the granular activated carbon (GAC) of 2.0, a mixing speed of 200 r/min, and a hydraulic retention time (HRT) of 1.5 h. In the meantime, the removal rate of chemical oxygen demand (COD) was up to 64.6%, and NH4-N and Pb in the influent were partly removed. After the micro-electrolysis process, the ratio of biochemical oxygen demand (BOD) to COD (B/C ratio) was greater than 0.6, thus providing a favorable basis for bioprocess treatment.

  15. 13C-NMR chemical shift databases as a quick tool to evaluate structural models of humic substances

    DEFF Research Database (Denmark)

    Nyrop Albers, Christian; Hansen, Poul Erik

    2010-01-01

    Models for humic and fulvic acids are discussed based on 13C liquid state NMR spectra combined with results from elemental analysis and titration studies. The analysis of NMR spectra is based on a full reconstruction of the NMR spectrum done with help of 13C-NMR data bases by adding up chemical s...

  16. Book of abstracts Chemical Engineering: IV All-Russian Conference on chemical engineering, All-Russian Youth Conference on chemical engineering, All-Russian school on chemical engineering for young scientists and specialists. Plenary reports. Engineering of inorganic substances and materials

    International Nuclear Information System (INIS)

    In the given volume of abstracts of the IV All-Russian Conference on chemical engineering, All-Russian Youth Conference on chemical engineering, All-Russian school on chemical engineering for young scientists and specialists (Moscow, March 18-23, 2012) there are the abstracts of the reports concerning chemical engineering of inorganic substances and materials. The abstracts deal with state-of-the-art and future development of theoretical and experimental investigations as well as with experience in practical realization of development works in the field of chemical engineering and relative areas

  17. pH Tolerance in Freshwater Bacterioplankton: Trait Variation of the Community as Measured by Leucine Incorporation

    OpenAIRE

    Bååth, Erland; Kritzberg, Emma

    2015-01-01

    pH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, covering in situ pH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) in...

  18. Prediction of cancer drugs by chemical-chemical interactions.

    Directory of Open Access Journals (Sweden)

    Jing Lu

    Full Text Available Cancer, which is a leading cause of death worldwide, places a big burden on health-care system. In this study, an order-prediction model was built to predict a series of cancer drug indications based on chemical-chemical interactions. According to the confidence scores of their interactions, the order from the most likely cancer to the least one was obtained for each query drug. The 1(st order prediction accuracy of the training dataset was 55.93%, evaluated by Jackknife test, while it was 55.56% and 59.09% on a validation test dataset and an independent test dataset, respectively. The proposed method outperformed a popular method based on molecular descriptors. Moreover, it was verified that some drugs were effective to the 'wrong' predicted indications, indicating that some 'wrong' drug indications were actually correct indications. Encouraged by the promising results, the method may become a useful tool to the prediction of drugs indications.

  19. Enhanced α-ketoglutaric acid production and recovery in Yarrowia lipolytica yeast by effective pH controlling.

    Science.gov (United States)

    Morgunov, Igor G; Kamzolova, Svetlana V; Samoilenko, Vladimir A

    2013-10-01

    The replacement of chemical synthesis by environmentally friendly energy-efficient technologies for production of valuable metabolites is a principal strategy of developing biotechnological industry all over the world. In the present study, we develop a method for α-ketoglutaric acid (KGA) production from rapeseed oil with the use of Yarrowia lipolytica yeast. Sixty strains of Y. lipolytica yeasts were tested for their ability to produce KGA, and the strain Y. lipolytica 212 (Y. lipolytica VKM Y-2412) was selected as a promising KGA producer. Using a three-stage pH controlling, in which pH was 4.5 in the growth phase, then since 72 to 144 h, pH was maintained at 3.5 and in the later phase of acid production, the titration by KOH was switch off, selected strain produced 106.5 g l(-1) of KGA with mass yield of 0.95 g g(-1). KGA in the form of monopotassium salt was isolated from the culture broth and purified. The isolation procedure involved separation of biomass, extraction of residual triglycerides, filtrate bleaching, and acidification with mineral acid (to pH 2.8-3.4), concentration, precipitation of mineral salts, and crystallization of the product. The purity of KGA isolated from the culture filtrate reached 99.1 %. PMID:23948727

  20. Biofilm biomass disruption by natural substances with potential for endodontic use

    Directory of Open Access Journals (Sweden)

    Flávio Rodrigues Ferreira Alves

    2013-02-01

    Full Text Available This study evaluated the in vitro effects of four natural substances on the biomass of bacterial biofilms to assess their potential use as root canal irrigants. The following substances and their combinations were tested: 0.2% farnesol; 5% xylitol; 20% xylitol; 0.2% farnesol and 5% xylitol; 0.2% farnesol, 5% xylitol, and 0.1% lactoferrin; 5% xylitol and 0.1% lactoferrin; and 20 mM salicylic acid. The crystal violet assay was used to evaluate the effects of these substances on the biomass of biofilms formed by Enterococcus faecalis and Staphylococcus epidermidis. All substances except for 20 mM salicylic acid and 20% xylitol reduced biofilm mass when compared to controls. The combination of farnesol and xylitol was the most effective agent against E. faecalis ATCC 29212 (p < 0.05. Farnesol combined with xylitol and lactoferrin was the most effective against biofilms of the endodontic strain of E. faecalis MB35 (p < 0.05. Similarly, combinations involving farnesol, xylitol, and lactoferrin reduced the biomass of S. epidermidis biofilms. In general, farnesol, xylitol, and lactoferrin or farnesol and xylitol reduced biofilm biomass most effectively. Therefore, it was concluded that combinations of antibiofilm substances have potential use in endodontic treatment to combat biofilms.

  1. The effect of chemical treatments on the pH & microbial flora of cassava residues during storage

    Directory of Open Access Journals (Sweden)

    Thaísa Anders Carvalho Souza

    2013-09-01

    Full Text Available Cassava starch factories produce residues that can be commercialized as food ingredients. The objective of this study was to evaluate the microbiological safety of cassava peel and bagasse during storage, with and without chemical treatment. The bagasse was acidified with lactic acid, and the peel was immersed in a sodium hypochlorite solution. The microbiological analyses were carried out for 72 h after harvest. All of the samples showed the absence of pathogenic microorganisms, and the acidification and sanitization were effective in controlling total coliforms. Cassava bagasse and peel samples can be considered safe for consumption by humans as ingredients for other food products.

  2. Dissolution enhancement of gliclazide using pH change approach in presence of twelve stabilizers with various physico-chemical properties

    OpenAIRE

    Talari, Roya; Nokhodchi, Ali; Mostafavi, Seyed Abolfazl; Varshosaz, Jaleh

    2009-01-01

    Purpose. The micronization using milling process to enhance dissolution rate is extremely inefficient due to a high energy input, and disruptions in the crystal lattice which can cause physical or chemical instability. Therefore, the aim of the present study is to use in situ micronization process through pH change method to produce micron-size gliclazide particles for fast dissolution hence better bioavailability. Methods. Gliclazide was recrystallized in presence of 12 different stabilizers...

  3. Influence of medium composition and pH on the production of polygalacturonases by Aspergillus oryzae

    OpenAIRE

    Eloane Malvessi; Mauricio Moura da Silveira

    2004-01-01

    A liquid medium containing wheat bran, salts and a source of inducer (pectin) was found to be suitable for the production of exo- and endo-polygalacturonases by Aspergillus oryzae CCT3940. Induction of polygalacturonases by purified pectin was significantly higher than when rinds of citrus fruits were used as inducer. A. oryzae growth was favoured by pH close to 4, although a drop of pH to around 3 was needed for enzymes production. Afterwards, decreasing activities were observed with the nor...

  4. Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry

    OpenAIRE

    L. Rondo; Flagan, R. C.

    2016-01-01

    Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H_2SO_4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantita...

  5. Double-walled carbon nanotubes suspending by natural active substances (saponins and humic acids

    Directory of Open Access Journals (Sweden)

    Zafour-Hadj-Ziane A.

    2013-09-01

    Full Text Available Carbon nanotubes (CNTs discovered over the past fifteen years are very interesting materials because of their structural, mechanical, chemical and electronic properties. However, their poor dispersion after synthesis constitutes a real obstacle to their use in varied fields. To respond to a topical issue, we proposed a new concept based on the use of natural active substances such a saponins; biosurfactant extracted from the tree Sapindus Mukorossiand humic acids. The results showed that for a concentration of 1.5 mg/l of saponin and 5 mg/l of humic acids, the stable suspensions were obtained; the zeta potential measurements have justified these results.

  6. Iron biofortification of wheat grains through integrated use of organic and chemical fertilizers in pH affected calcareous soil.

    Science.gov (United States)

    Ramzani, Pia Muhammad Adnan; Khalid, Muhammad; Naveed, Muhammad; Ahmad, Rashid; Shahid, Muhammad

    2016-07-01

    Incidence of iron (Fe) deficiency in human populations is an emerging global challenge. This study was conducted to evaluate the potential of iron sulphate combined with biochar and poultry manure for Fe biofortification of wheat grains in pH affected calcareous soil. In first two incubation studies, rates of sulfur (S) and Fe combined with various organic amendments for lowering pH and Fe availability in calcareous soil were optimized. In pot experiment, best rate of Fe along with biochar (BC) and poultry manure (PM) was evaluated for Fe biofortification of wheat in normal and S treated low pH calcareous soil. Fe applied with BC provided fair increase in root-shoot biomass and photosynthesis up to 79, 53 and 67%, respectively in S treated low pH soil than control. Grain Fe and ferritin concentration was increased up to 1.4 and 1.2 fold, respectively while phytate and polyphenol was decreased 35 and 44%, respectively than control in treatment where Fe was applied with BC and S. In conclusion, combined use of Fe and BC could be an effective approach to improve growth and grain Fe biofortification of wheat in pH affected calcareous soil. PMID:27179316

  7. Substance Use during Pregnancy Varies by Race and Ethnicity

    Science.gov (United States)

    ... Abuse and Mental Health Services Administration (SAMHSA). The survey collects data by administering questionnaires to a representative sample of the population through face-to-face interviews at their places of residence. ...

  8. Synthesis of polysaccharide chemical gels by gamma-irradiation

    International Nuclear Information System (INIS)

    Recently many biodegradable hydrogel systems have been developed in the area of controlled drug delivery. In previous studies, the authors prepared biodegradable hydrogels by crosslinking natural polymers, such as albumin and dextran, using gamma-irradiation. Natural polymers were functionalized by introducing double bonds through reaction with glycidyl acrylate. The functionalized polymers were then crosslinked to form chemical gels by exposure to gamma-irradiation. In this study, they examined the ability of various polysaccharides to form chemical gels by gamma-irradiation. Dextran, alginic acid, hyaluronic acid, benzyl esters of hyaluronic acid, and gellan were functionalized. The effects of the polymer concentration and the gamma-irradiation dose on the hydrogel formation were examined. All the polysaccharides used formed chemical gels, although the extent of gel formation was different. For alginic acid, hyaluronic acid, and benzyl ester of hyaluronic acid at 25% of esterification degree, the chemical gels were formed at lower polymer concentration and at lower gamma-irradiation dose, if the solution was acidified to pH 3. The ability to form chemical gels with various natural polymers would be useful in the development of controlled drug delivery systems

  9. Influence of medium composition and pH on the production of polygalacturonases by Aspergillus oryzae

    Directory of Open Access Journals (Sweden)

    Eloane Malvessi

    2004-09-01

    Full Text Available A liquid medium containing wheat bran, salts and a source of inducer (pectin was found to be suitable for the production of exo- and endo-polygalacturonases by Aspergillus oryzae CCT3940. Induction of polygalacturonases by purified pectin was significantly higher than when rinds of citrus fruits were used as inducer. A. oryzae growth was favoured by pH close to 4, although a drop of pH to around 3 was needed for enzymes production. Afterwards, decreasing activities were observed with the normal increase in pH to near neutrality. The highest activities were achieved with an initial pH of 4 and controlled when it decreased to a value slightly below 3 (159 units endo-PG.mL-1 at 83 h and 45 units exo-PG.mL-1 at 64 h, being the loss in polygalacturonases activities strongly reduced at this condition. The best values of pH and temperature for the action of exo-PG (4.5/57ºC and endo-PG (4.3/40ºC were assessed.Um meio líquido contendo farelo de trigo, sais e fonte de indutor (pectina foi definido para a produção de exo e endo-poligalacturonases por Aspergillus oryzae CCT3940. A indução por pectina purificada foi significativamente maior que a observada com cascas de cítricos. O crescimento de A. oryzae é favorecido por valores de pH próximos a 4, embora uma queda até valor em torno de 3 seja necessária para a produção das enzimas. Posteriormente, atividades decrescentes foram observadas com a subida normal do pH até próximo à neutralidade. As maiores atividades foram alcançadas quando o processo foi iniciado em pH 4 e controlado quando decresceu até níveis ligeiramente abaixo de 3 (159 unidades.mL-1 para endo-PG, em 83 h, e 45 unidades.mL-1, em 64 h, para exo-PG, com a perda de atividades sendo drasticamente reduzida. Os melhores valores de pH e temperatura para a ação de exo-PG (4,5/57°C e endo-PG (4,3/40ºC foram estimados.

  10. The monitoring of radioactive substances in biological food chains by the veterinary service in Czechoslovakia

    International Nuclear Information System (INIS)

    Czechoslovakia has established an environmental monitoring system to protect the hygienic conditions of the environment from the radiation hazard. The control authorities of the Ministry of Agriculture and Food take part in this system in order to collect information on the contamination with radioactive substances of soil, plants, game, food animals, foodstuffs and raw materials, i.e. information on all links of the food chain which extends from animals to man. A radioactive substances detection programme has been launched by the appropriate authorities in agriculture, animal husbandry and veterinary service. The programme includes a two-stage laboratory analysis of radioactive substances. The majority of laboratories covering the programme are already in operation

  11. Hidden substances identification by detection of fast neutron induced γ rays using associated α particle technique

    International Nuclear Information System (INIS)

    Measurements have been made of characteristic gamma rays spectra from A(n,n'γ)A reactions induced by 14.1 MeV neutrons on bulk samples of different substances: C, H2O, SiO2, C3H6N6 and samples of soil. Background radiation was reduced by the associated alpha particle technique

  12. The effect of pH on the synthesis of stable Cu2O/CuO nanoparticles by sol-gel method in a glycolic medium

    Science.gov (United States)

    Zayyoun, N.; Bahmad, L.; Laânab, L.; Jaber, B.

    2016-05-01

    In this work, we demonstrate that using a glycolic medium, both stable CuO and Cu2O nanoparticles can be elaborated from Cu colloidal particles by adjusting their chemical environment, in particular the acido-basicity of the solution. In this context, the effect of pH on the sol-gel synthesis of Cu2O/CuO NPs was investigated. XRD results confirmed the formation of pure Cu2O with a cubic structure at lower pH (pH ≤ 6), whereas the pure monoclinic CuO was formed at higher pH (pH ≥ 12). TEM image indicates that the as-formed CuO NPs in basic pH are spherical in shape and their average size is found to be in the range of 4.5 nm. However, the as-obtained Cu2O NPs in acid pH are cubical, with an average diameter of about 3 nm, and agglomerated into large spherical particles under the effect of ethylene glycol. Using the UV-Vis spectroscopy, the measured band gap energies of the prepared Cu2O and CuO NPs are 2.07 and 4.08 eV respectively. FTIR results confirm the purity of the synthesized CuO and Cu2O nanoparticles.

  13. Monosilicate adsorption by ferrihydrite and goethite at pH 3-6

    DEFF Research Database (Denmark)

    Hansen, Hans Christian Bruun; Raben-Lange, B.; Raulund-Rasmussen, Karsten;

    1994-01-01

    The constant capacitance model and the Elovich equation were combined in the following mathematical expression enabling calculation of the amount of silicic acid adsorbed by iron oxides as a function of the Si concentration, pH, soil:solution ratio, and reaction time: [GRAPHICS] K(a1) is the...... protolytic surface constant and K(Si) is the stability constant for the Fe oxide-silicate surface complex; -logK(a1) = 6.40-0.54(8-pH) and logK(Si) = 3.85 for ferrihydrite and goethite. Good agreement was found between calculated Si adsorption and the amount actually found to be adsorbed by synthetic...... ferrihydrite and goethite at different pH (3-6), Si concentration (1-600 muM), solid:solution ratio (1:300, 1:1200) and reaction time (1-480h)....

  14. Role of "active" potassium transport in the regulation of cytoplasmic pH by nonanimal cells.

    OpenAIRE

    Blatt, M.R.; Slayman, C L

    1987-01-01

    High-affinity potassium uptake in Neurospora occurs by symport with protons [Km (apparent) = 15 microM at pH 5.8], for which a large inward gradient (approximately 400 mV) is generated by the H+-extruding ATPase of the plasma membrane. Operating in parallel, the two transport systems yield a net 1:1 exchange of K+ for cytoplasmic H+. Since this exchange could play a role in cytoplasmic pH (pHi) regulation, the coordinated functioning of the K+-H+ symport and H+ pump has been examined during a...

  15. Effect of pH on cadmium biosorption by coconut copra meal

    International Nuclear Information System (INIS)

    Biosorption of cadmium ion by coconut copra meal, an agricultural waste product was investigated as a function of initial solution pH and initial cadmium concentration. Pseudo-second-order kinetic analyses were performed to determine the rate constant of biosorption, the equilibrium capacity, and initial biosorption rate. Cadmium biosorption by copra meal was found to be dependent on the initial solution pH and initial cadmium concentration. Ion exchange occurred in the initial biosorption period. In addition, mathematical relationships were drawn to relate the change in the solution hydrogen ion concentration with equilibrium biosorption capacity, initial cadmium concentration, and equilibrium biosorption capacity

  16. A new method to control electrolytes pH by circulation system in electrokinetic soil remediation.

    Science.gov (United States)

    Lee, H H; Yang, J W

    2000-10-01

    To simultaneously avoid a decrease of electro-osmotic flow by hydrogen ions and to increase heavy metal precipitation due to hydroxide ions, simulated electrokinetic remediation was conducted in saturated kaolinite specimens loaded with lead(II) using an electrolyte circulation method to control electrolyte pH. At an electrolyte circulation rate of 1.1 ml/min, it was possible to increase the anolyte pH from 2 to 4 and decrease the catholyte pH from 12 to 8. Using electrolyte circulation, it was observed that the rate of decrease of clay pH due to the change of electrolyte pH was reduced. As a result, the operable period was extended and the removal efficiency for lead(II) was also increased. It was observed that most of the effluent lead(II) from the cathode compartment was electroplated onto the cathode and that residual effluent lead(II) did not precipitate onto, or adsorb to, the clay at the anode compartment during circulation. Therefore, there was no need to treat the electrolyte because there was virtually no effluent from the cathode compartment in the circulation system. It was also found that the electrolyte volume required to sustain the electrolytic reaction was sufficient for the whole electrokinetic remediation process. PMID:10946130

  17. Microencapsulation of liquid and solid substances by reactive polymers.

    Science.gov (United States)

    Shevchuk, O; Serdiuk, V; Bukartyk, N; Moncibovich, R; Tokarev, V

    2014-01-01

    This study is devoted to the development of techniques for the formation of polymeric microcapsules (MC) with either liquid or solid core and with the polymer shell containing diverse functional groups on the basis of new reactive functional copolymers (FC). Two approaches to the formation of MC containing FC shell that included the stages of "oil-in-water" or "water-in-oil" dispersion preparation followed by slow extraction of solvents from dispersed phase by dispersive media were examined. FC with the same structure was successfully applied for both "oil-in-water" and "water-in-oil" systems. Spherical MC with the liquid hydrocarbon core demonstrated essential increase in their volume after heating at the temperature exceeding a boiling point of hydrocarbon encapsulated. Presence of reactive groups in the MC shell opens up new opportunity for further tuning the MC properties via their interaction with proper compounds, particularly via graft-polymerisation of diverse vinyl monomers initiated from the MC surface. PMID:24697175

  18. PubChem Substance and Compound databases.

    Science.gov (United States)

    Kim, Sunghwan; Thiessen, Paul A; Bolton, Evan E; Chen, Jie; Fu, Gang; Gindulyte, Asta; Han, Lianyi; He, Jane; He, Siqian; Shoemaker, Benjamin A; Wang, Jiyao; Yu, Bo; Zhang, Jian; Bryant, Stephen H

    2016-01-01

    PubChem (https://pubchem.ncbi.nlm.nih.gov) is a public repository for information on chemical substances and their biological activities, launched in 2004 as a component of the Molecular Libraries Roadmap Initiatives of the US National Institutes of Health (NIH). For the past 11 years, PubChem has grown to a sizable system, serving as a chemical information resource for the scientific research community. PubChem consists of three inter-linked databases, Substance, Compound and BioAssay. The Substance database contains chemical information deposited by individual data contributors to PubChem, and the Compound database stores unique chemical structures extracted from the Substance database. Biological activity data of chemical substances tested in assay experiments are contained in the BioAssay database. This paper provides an overview of the PubChem Substance and Compound databases, including data sources and contents, data organization, data submission using PubChem Upload, chemical structure standardization, web-based interfaces for textual and non-textual searches, and programmatic access. It also gives a brief description of PubChem3D, a resource derived from theoretical three-dimensional structures of compounds in PubChem, as well as PubChemRDF, Resource Description Framework (RDF)-formatted PubChem data for data sharing, analysis and integration with information contained in other databases. PMID:26400175

  19. Identification of the antimicrobial substances produced by Solanum palinacanthum (Solanaceae

    Directory of Open Access Journals (Sweden)

    Aline C. Pereira

    2008-09-01

    Full Text Available To find out natural antimicrobial agents as alternative in therapeutics and to preserve food, the methanol extract of Solanum palinacanthum aerial parts was submitted to purification steps guided by antibacterial and antifungal assays. As a consequence, the flavonoid rutin and 3,5-dicaffeoylquinic acid were isolated by column chromatographyand high performance liquid chromatography, and identified by mass and nuclear magnetic resonance spectrometry. Minimal inhibitory concentrations (MIC of the quinic acid derivative against Aeromonas hydrophila, Bacillus subtilis, Staphylococcus aureus and the fungus Aspergillus ochraceus were 250, 1000, 1000 and > 568µg/mL, respectively. Against the same microorganisms, MIC for rutin were 1000, > 1000, > 1000 and 35µg/mL, respectively. Rutinwas very promising for A. ochraceus control, since its MIC against such fungus was close to the one observed for benzalkonium chloride, which is used as a fungicide in Brazil.Com vistas a descobrir antimicrobianos de origem natural para uso terapêutico ou para a preservação de alimentos, o extrato metanólico das partes aéreas de Solanum palinacanthum foi submetido a fracionamentos direcionados por testes para avaliar a atividade antibacteriana e antifúngica. Em decorrência, o flavonóide rutina e o ácido 3,5-dicafeoilquínico foram isolados por cromatografia em coluna e por cromatografia líquida de alta eficiência, para serem identificados por espectrometria de massas e de ressonância magnética nuclear. As concentrações inibitórias mínimas (CIM do derivado do ácido cafeico contra Aeromonas hydrophila, Bacillus subtilis, Staphylococcus aureus e o fungo Aspergillus ochraceus foram 250, 1000, 1000 e > 568µg/mL, respectivamente. Contra os mesmos organismos, os valores de CIM para a rutina foram 1000, > 1000, > 1000 e 35µg/mL, respectivamente. A rutina mostrou-se muito promissora para o controle de A. ochraceus, pois seu valor de CIM contra tal fungo foi bem

  20. Enhanced Dissolution of Silicate Minerals by Bacteria at Near-Neutral pH

    Energy Technology Data Exchange (ETDEWEB)

    Vandevivere, P.; Welch, S. A.; Ullman, W. J.; Kirchman, D. L.

    1994-01-10

    Almost half of 17 bacterial isolates examined in this study stimulated by townite feldspar dissolution at near-neutral pH while in a resting state in buffered glucose. Most of the isolates that stimulated dissolution produced gluconic acid by the partial oxidation of glucose during the experiment.

  1. Temporal changes of lysosome and phagosome pH during phagolysosome formation in macrophages: studies by fluorescence spectroscopy

    OpenAIRE

    1981-01-01

    Intravascular pH was measured within the lysosomes and newly formed phagosomes in cultured mouse peritoneal macrophages. The kinetics of pH change in both vacuolar systems was quantitatively determined within a large cell population by fluorescence spectroscopy. Additionally, pH changes within individual phagosomes were followed semiquantitatively using indicator dyes. Two novel findings were made. Firstly, the pH in new phagosomes was transiently driven alkaline (higher than physiological) e...

  2. Effects of pH and Corn Steep Liquor Variability on Mannitol Production by Lactobacillus intermedius NRRL B-3693

    Science.gov (United States)

    Lactobacillus intermedius NRRL B-3693 produce mannitol, lactic acid, and acetic acid when grown on fructose at 37 deg C. The optimal pH for mannitol production from fructose by the heterofermentative lactic acid bacterium (LAB) in pH controlled fermentation was at pH 5.0. It produced 160.7±1.1 g m...

  3. Enhancing microbial iron reduction in hyperalkaline, chromium contaminated sediments by pH amendment

    International Nuclear Information System (INIS)

    Soil collected from beneath a chromite ore processing residue (COPR) disposal site contained a diverse population of anaerobic alkaliphiles, despite receiving a continuous influx of a Cr(VI) contaminated, hyperalkaline leachate (pH 12.2). Chromium was found to have accumulated in this soil as a result of an abiotic reaction of Cr(VI) with Fe(II) present in the soil. This sediment associated Fe(II) was, therefore, acting as a natural reactive zone beneath the COPR and thereby preventing the spread of Cr(VI). In anaerobic microcosm experiments soil microorganisms were able to reduce NO3- at pH 11.2 coupled to the oxidation of electron donors derived from the original soil organic matter, but progressive anoxia did not develop to the point of Fe reduction over a period of 9 months. It is not clear, therefore, if Fe(II) can be actively replenished by microbial processes occurring within the soil at in situ conditions. Sodium bicarbonate was added to this soil to investigate whether bioreduction of Fe in hyperalkaline Cr contaminated soils could be enhanced by reducing the pH to a value optimal for many alkaliphilic bacteria. The addition of NaHCO3 produced a well buffered system with a pH of ∼9.3 and Fe reducing conditions developed within 1 month once complete denitrification had occurred. Fe(III) reduction was associated with an increase in the proportion of genetic clone libraries that were from the phylum Firmicutes, suggesting that these species are responsible for the Fe(III) reduction observed. Amendment of the pH using bicarbonate may provide a suitable strategy for stimulating the bioreduction of Fe(III) in COPR leachate contaminated soils or other environments where microbial reduction is inhibited by elevated pH.

  4. Effect of pH and nitrogen source in carboxylation by seedlings of wheat and maize

    International Nuclear Information System (INIS)

    Carboxylation has been studied in leaves homogenate, expressed as RuBP-carboxylase activity, using as one of the substrates NaH14CO3, and giving the acitivity value as nanomols of 14CO2 incorporated by mg.. of protein per minute in the determined conditions. The variable is the pH of the culture media. Cultures has been studied with pH values between 3.5 and 6.2. Three different nitrogen sources has been used, carefully calculating the composition of each medium in order that all of them have same nitrogen content:1) Nitrate medium, 2) Ammonium sulfate medium and 3) Ammonium nitrate medium. The results are presented graphically with a discussion about them. It is shown that the effect of pH is less pronounced in maize that in wheat, with NO3 nitrogen source that with NH4+, and in plants 28 days age than in plants 7 days age. (author)

  5. Improvement of chemical monitoring of water-chemistry conditions at thermal power stations based on electric conductivity and pH measurements

    Science.gov (United States)

    Larin, A. B.; Larin, B. M.

    2016-05-01

    The increased requirements to the quality of the water heat conductor for working superhigh (SHP) and supercritical (SCP) pressure power plants and promising units, including combined-cycle gas turbine (CCGT) units and power plants with ultrasupercritical parameters (USCPs), can largely be satisfied through specific electric conductivity and pH measurements for cooled heat conductor samples combined with calculations of ionic equilibria and indirect measurements of several specified and diagnostic parameters. The possibility of calculating the ammonia and chloride concentrations and the total concentration of hardness and sodium cations in the feed water of drum-type boilers and the phosphate and salt contents in boiler water was demonstrated. An equation for evaluating the content of potentially acid substances in the feed water of monotube boilers was suggested. The potential of the developed procedure for evaluating the state of waterchemistry conditions (WCCs) in power plants with CCGT units was shown.

  6. Effect of pH on Cleavage of Glycogen by Vaginal Enzymes

    OpenAIRE

    Spear, Greg T.; McKenna, Mary; Landay, Alan L.; Makinde, Hadijat; Hamaker, Bruce; French, Audrey L.; Lee, Byung-Hoo

    2015-01-01

    Glycogen expressed by the lower genital tract epithelium is believed to support Lactobacillus growth in vivo, although most genital isolates of Lactobacillus are not able to use glycogen as an energy source in vitro. We recently reported that α-amylase is present in the genital fluid of women and that it breaks down glycogen into small carbohydrates that support growth of lactobacilli. Since the pH of the lower genital tract can be very low, we determined how low pH affects glycogen processin...

  7. Regulation of Gene Expression by Ambient pH in Filamentous Fungi and Yeasts

    OpenAIRE

    Peñalva, Miguel A.; Arst, Herbert N.

    2002-01-01

    Life, as we know it, is water based. Exposure to hydroxonium and hydroxide ions is constant and ubiquitous, and the evolutionary pressure to respond appropriately to these ions is likely to be intense. Fungi respond to their environments by tailoring their output of activities destined for the cell surface or beyond to the ambient pH. We are beginning to glimpse how they sense ambient pH and transmit this information to the transcription factor, whose roles ensure that a suitable collection o...

  8. Synthesis of YAG nanopowder by the co-precipitation method: Influence of pH and study of the reaction mechanisms

    International Nuclear Information System (INIS)

    YAG nanopowders with an average grain size of 30 nm have been successfully synthesized by the co-precipitation method using nitrates with precipitant of ammonium hydrogen carbonate. The influence of precipitation conditions such as pH, aging time and calcination temperature on the formation of secondary phases has been studied. The accurate control of pH value at every stage of precipitation process is crucial to avoid the presence of YAM (Yttrium Aluminium Monoclinic, Y4Al2O9) and yttrium oxide (Y2O3) after calcination. The reaction mechanisms have been investigated using different techniques such as infrared spectroscopy, x-ray diffraction and thermal analyses. The YAG phase is formed around 1050 °C passing through an intermediate phase called YAP (Yttrium Aluminium Perovskite, YAlO3). Local chemical heterogeneities are responsible for the deviation of the Y:Al ratio and the formation of YAP during heat treatment. - Graphical abstract: Synthesis of YAG nanopowder by the co-precipitation method: Influence of pH and study of the reaction mechanisms, Marlot et al. Highlights: ► Synthesis of pure YAG nanoparticles by the co-precipitation method. ► Influence of pH value on the formation of secondary phases all along the process. ► Study of the importance of pH using titration method. ► Chemical evolution of the precursor during calcinations. ► Proposition for reaction mechanisms.

  9. Pu(V) reduction and enhancement of particle-water partitioning by exopolymeric substances

    International Nuclear Information System (INIS)

    Central to understanding the environmental behavior of Pu in vadose- and saturated-zones, as well as waste streams, is the contribution of colloidal natural organic mater (NOM), e.g., biopolymeric exopolymeric substances (EPS) from Pseudomonas fluorescens Biovar II and geopolymeric humic acids (HA), to Pu speciation. Because Pu(V) and Pu(IV) are present in aquatic systems at sub-pM concentrations, many established techniques for chemical speciation and oxidation state determination are not available. However, the two redox states of Pu can be distinguished through their tendency to form colloidal species. Controlled laboratory experiments with low-colloid background solutions of 0.1 M NaClO4 with an inert buffer (Tris) and 5 μm silica particles of high specific surface area (500 m2/g) and small (3 nm) pores investigated the ability of NOM compounds for their binding and redox qualities showed that: (1) Pu(V) and Pu(IV) tracers at pM concentrations could be distinguished by their tendency to bind to colloidal species (≥ 1 kDa), with binding extent being high for Pu(IV), and low for Pu(V); (2) EPS can significantly enhance particle- (or colloid-) water partition coefficients to silica particles (Kd, Kdc), quickly (1 day) for Pu(IV) and slowly (1 month) for Pu(V); (3) Pu(V), in the presence of EPS and silica particles can become associated with particles and colloids over periods of months, likely indicating reduction: (4) Kd values can be affected by the reaction sequence of tracer addition to the solution containing silica particles and NOM compounds (e.g., EPS or HA). (orig.)

  10. Methodological guide: management of industrial sites potentially contaminated by radioactive substances

    International Nuclear Information System (INIS)

    At the request of the Ministries of Health and the Environment, IPSN is preparing and publishing the first version of the methodological guide devoted to managing industrial sites potentially contaminated by radioactive substances. This guide describes a procedure for defining and choosing strategies for rehabilitating such industrial sites. (author)

  11. [Influence of pH on Kinetics of Anilines Oxidation by Permanganate].

    Science.gov (United States)

    Wang, Hui; Sun, Bo; Guan, Xiao-hong

    2016-02-15

    To investigate the effect of pH on the oxidation of anilines by potassium permanganate, aniline and p-Chloroaniline were taken as the target contaminants, and the experiments were conducted under the condition with potassium permanganate in excess over a wide pH range. The reaction displayed remarkable autocatalysis, which was presumably ascribed to the formation of complexes by the in situ generated MnOx and the target contaminants on its surface, and thereby improved the oxidation rate of the target contaminants by permanganate. The reaction kinetics was fitted with the pseudo-first-order kinetics at different pH to obtain the pseudo-first-order reaction constants (k(obs)). The second-order rate constants calculated from permanganate concentration and k,b, increased with the increase of pH and reached the maximum near their respective pKa, after which they decreased gradually. This tendency is called parabola-like shaped pH-rate profile. The second-order rate constants between permanganate and anilines were well fitted by the proton transfer model proposed by us in previous work. PMID:27363148

  12. Synthesis of Nanocrystalline SnOx (x = 1–2 Thin Film Using a Chemical Bath Deposition Method with Improved Deposition Time, Temperature and pH

    Directory of Open Access Journals (Sweden)

    Zulkarnain Zainal

    2011-09-01

    Full Text Available Nanocrystalline SnOx (x = 1–2 thin films were prepared on glass substrates by a simple chemical bath deposition method. Triethanolamine was used as complexing agent to decrease time and temperature of deposition and shift the pH of the solution to the noncorrosive region. The films were characterized for composition, surface morphology, structure and optical properties. X-ray diffraction analysis confirms that SnOx thin films consist of a polycrystalline structure with an average grain size of 36 nm. Atomic force microscopy studies show a uniform grain distribution without pinholes. The elemental composition was evaluated by energy dispersive X-ray spectroscopy. The average O/Sn atomic percentage ratio is 1.72. Band gap energy and optical transition were determined from optical absorbance data. The film was found to exhibit direct and indirect transitions in the visible spectrum with band gap values of about 3.9 and 3.7 eV, respectively. The optical transmittance in the visible region is 82%. The SnOx nanocrystals exhibit an ultraviolet emission band centered at 392 nm in the vicinity of the band edge, which is attributed to the well-known exciton transition in SnOx. Photosensitivity was detected in the positive region under illumination with white light.

  13. Effects of Electrolyte Anions and pH on Adsortpion of Sulfate by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    ZHANGGANGYA; G.M.BRUEMMER; 等

    1996-01-01

    The effects of three electrolyte anions,ionic strength and pH on the adsorption of sulfate by two variable charge soils,with different surface charge properties were studied.Under the conditions of the same pH and ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of Cl->NO3->ClO4-,indicating the difference of the nature among these three anions.For ferralsol in the same concentration of chloride and perchloride solutions,the two sulfate adsorption-pH curves could intersect at certain pH value.When pH was higher than the intersecting point.more sulfate was adsorbed in the perchloride solution,while when it was lower than the intersecting point,more sulfate was adsorbed in the chloride solution.In different concentratioins of electrolyte solution,the curves of the amount of oxy-acid anion adsorbed,which changed with pH,could intersect at a certain pH,which is termed point of zero salt effect(PZSE) on adsortpion.The nature of electrolyte anions influenced obviously the appearace of PZSE for sulfate adsorption.For ferralsol the curves of adsorption converged to about pH 7 in NaCl solution seemed to intersect in NaNO3 solution and to have a typical PZSE for sulfate adsorption in NaClO4 solution,For Acrisol the three curves of adsorption were nearly parallel in NaCl and NaNO3 solutions and converged to pH 6.5 in NaClO4 solution.

  14. Completing a PhD by Publication: A Review of Australian Policy and Implications for Practice

    Science.gov (United States)

    Jackson, Denise

    2013-01-01

    There is increasing impetus for higher-degree-by-research students to publish during candidature. Research performance, including higher degree completions and publication output, commonly determines university funding, and doctorates with publishing experience are better positioned for a career in softening academic labour markets. The PhD by…

  15. EFFECTS OF PH ON DECHLORINATION OF TRICHLOROETHYLENE BY ZERO-VALENT IRON

    Science.gov (United States)

    The reduction rates of trichloroethylene (TCE) using zero-valent iron (ZVI) and the rates of iron hydrolysis were characterized at pH values of 5 to 10. The reduction of TCE by ZVI was carried out in batch reactors filled with pH-buffered (phosphate based) solutions under anaerob...

  16. pH stable thin film composite polyamine nanofiltration membranes by interfacial polymerisation

    NARCIS (Netherlands)

    Lee, Kah P.; Zheng, Jumeng; Bargeman, Gerrald; Kemperman, Antoine J.B.; Benes, N.E.

    2015-01-01

    In this work polyamine membranes are presented that are prepared by the interfacial polymerisation of polyethylenimine and cyanuric chloride on porous polyethersulfone supports. The thin film composite polyamine membranes have superior pH stability as compared to conventional polyamide membranes tha

  17. Methodological guide: management of industrial sites potentially contaminated by radioactive substances; Guide methodologique: gestion des sites industriels potentiellement contamines par des substances radioactives

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    At the request of the Ministries of Health and the Environment, IPSN is preparing and publishing the first version of the methodological guide devoted to managing industrial sites potentially contaminated by radioactive substances. This guide describes a procedure for defining and choosing strategies for rehabilitating such industrial sites. (author)

  18. Chemical and spectroscopic characterization of dissolved humic substances in a mangrove-fringed estuary in the eastern coast of Hainan Island, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yaoling; DU Jinzhou; PENG Bo; ZHANG Fenfen; ZHAO Xin; ZHANG Jing

    2013-01-01

    Mangrove-derived dissolved organic matter (DOM) has an important effect on estuarine and coastal area on a large scale.In order to improve the understanding of origin,composition,and fate of DOM in mangrove-fringed estuarine and coastal areas,dissolved humic substances (DHS) were isolated from one mangrove pore-water sample and one near-shore seawater sample downstream the mangrove pore-water site in the eastern coast of Hainan Island,South China.Fulvic acids,humic acids and XAD-4 fractions were obtained from the two water samples by using a two-column array of XAD-8 and XAD-4 resins.Chemical and spectroscopic methods were used to analyze the features of these DHS.Compared to the mangrovepore-water DHS,the near-shore seawater DHS were found rich in 13C with lower C/N ratios and more aliphatic compounds and carbohydrates,but less aromatic structures and carboxyl groups.As for the three fractions of the two DHS,XAD-4 fractions contain more aliphatics,carbohydrates,carboxyl groups,and enrich in 13C with respect to both fulvic and humic acids.Photo-oxidation transformation and contribution from marine-derived DOM were considered as the main reasons resulted in the difference in compositional features for these DHS in this study.

  19. α--AMYLASES OF Aspergillus flavus var. oryzae AND Bacillus subtilis: THE SUBSTRATE SPECIFICITY AND RESISTANCE TO A NUMBER OF CHEMICALLY ACTIVE SUBSTANCES

    Directory of Open Access Journals (Sweden)

    K. V. Avdiyuk

    2013-06-01

    Full Text Available The ability of Aspergillus flavus var. oryzae 80428 and Bacillus subtilis 147 α-amylases to split different carbohydrate-containing substrates, such as maltose, sucrose, trehalose, dextrin, α- and β-cyclodextrin, amylose, amylopectin, glycogen, pullulan, soluble starch, insoluble starch, corn starch, wheat starch, dextran 500 has been studied. It was shown that investigated enzymes differ by substrate specificity. α-Amylase of A. flavus var. oryzae 80428 rapidly hydrolysed soluble potato and wheat starch, while the α-amylase of B. subtilis 147 — only wheat starch. Both enzymes don’t cleave maltose, α-cyclodextrin and dextran 500. A. flavus var. oryzae 80428 α-amylase display very small ability to hydrolyze pullulan, while α-amylase of B. subtilis 147 it does not act in general. The lowest values of Michaelis constant for both enzymes at splitting of glycogen have been obtained, indicating that enzymes have the greatest affinity to this substrate. The studies of influence of chemically active substances on activity of A. flavus var. oryzae 80428 and B. subtilis 147 ?-amylases show there are resistant to urea, deoxycholic acid, Tween-80, Triton X-100 and hydrogen peroxide. It’s indicate the enzymes tested may be competitive in compare with earlier described in literature enzymes. The obtained results give a possibility to propose in future usage these enzymes in different fields of industry, foremost in detergent industry.

  20. Current direction, chemical, and marine toxic substances data from moored current meter casts and other instruments in the Gulf of Mexico during the Brine Disposal project, 09 September 1978 - 19 November 1979 (NODC Accession 8000043)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, marine toxic substances, and chemical data were collected using moored current meter casts and other instruments in the Gulf of Mexico from...

  1. Chemical, benthic organisms, zooplankton, marine toxic substances, and other data from moored current meter casts and other instruments in the Gulf of Mexico during the Brine Disposal project, 30 August 1979 - 21 September 1981 (NODC Accession 8200012)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, marine toxic substances, benthic organisms, zooplankton, and other data were collected using moored current meter casts and other instruments in the Gulf...

  2. Current direction, benthic organisms, zooplankton, chemical, toxis substances, and other data from moored current meter casts and other instruments in the Gulf of Mexico during the Brine Disposal project, 24 March 1981 - 19 February 1982 (NODC Accession 8200129)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current direction, benthic organisms, zooplankton, chemical, toxic substances, and other data were collected using moored current meter casts and other instruments...

  3. Chemical, zooplankton, and marine toxic substances data from moored current meter casts and other instruments in the Gulf of Mexico during the Brine Disposal project, 02 June 1978 - 02 June 1979 (NODC Accession 8000002)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, zooplankton, and marine toxic substances data were collected using moored current meter casts and other instruments in the Gulf of Mexico from June 2,...

  4. Prospective for remediation and purification of wastes from Xikuangshan mine by using Si-based substances.

    Science.gov (United States)

    Saihua, Liu; Xionghui, Ji; Yunhe, Xie; Jiang, John; Bocharnikova, Elena; Matichenkov, Vladimir

    2016-05-01

    Heavy metal mining includes several procedures producing water and solid wastes. These wastes may have high content of heavy metals and other pollutants. Usually, traditional technologies for purification of solid and liquid wastes are expensive and require a lot of special constructions. Recent investigations have shown that some Si-rich substances enable to regulate the mobility of pollutants in soil and water and enhance the plant resistance to its toxicity. Based on these findings, new way for purification of waste-waters and detoxification of pollutants can be elaborated. Laboratory test was conducted with contaminated solid and liquid wastes from Xikuangshan mine. In column and incubation tests, the contents and mobility of the following pollutants were evaluated in Si-treated and untreated samples: As, Cd, Co, Cr, Cu, Hg, Pb, Ni and Zn. The investigations have shown that the Si-rich substances can be used for filtration of contaminated waste-water. The concentrations of soluble pollutants were reduced by 5-10 times and more. The incubation tests with solid wastes and Si-rich compounds have demonstrated that some Si-based substances reduced the contaminant mobility by 2-4 times. The efficiency of tested substances depended on their solubility on Si. The data has demonstrated that some types of local materials including industrial wastes can be used for purification of waste-waters and detoxification of solid wastes. PMID:26921568

  5. Enhancement of Radiotherapeutic Efficacy by Paclitaxel-Loaded ph-Sensitive Block Copolymer Micelles

    International Nuclear Information System (INIS)

    Radiotherapy (RT) is a major modality for cancer treatment, but its efficacy is often compromised by the resistance caused by tumor-specific microenvironment including acidosis and hypoxia. For an effective RT, concurrent administration of radiosensitizer with RT has been emphasized. However, most anticancer agents enhancing radiotherapeutic efficacy have obstacles such as poor solubility and severe toxicity. Paclitaxel (PTX), a well-known radiosensitizer, is insoluble in water and needs toxic solvent like Cremophor EL. Nano materials in drug delivery systems have been utilized for improving the drawbacks of anti-cancer drugs. Solubilization, tumor accumulation, and toxicity attenuation of drug by nano materials are suitable for enhancement of radiotherapeutic efficacy. In this study, PTX was incorporated into ph-sensitive block copolymer micelle (psm-PTX), polyethylene glycol-graft-poly(β-amino ester), and pre clinically evaluated for its effect on RT. The size of psm-PTX was 125. 4.4±nm at ph 7.4. psm-PTX released PTX rapidly in the acidic condition (ph 6.5), while it was reasonably stable in the physiologic condition (ph 7.4). The clonogenic assay showed that psm-PTX greatly sensitized human non-small-cell lung cancer A549 cells to radiation. In the xenograft tumor model, the combination of psm-PTX and radiation significantly delayed the tumor growth. These results demonstrated the feasibility of psm-PTX to enhance the chemo radiotherapeutic efficacy.

  6. Submicrometer fiber-optic chemical sensors: Measuring pH inside single cells. Progress report, October 1990--August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Kopelman, R.

    1993-12-01

    Starting from scratch, we went in two and a half years to 0.04 micron optical microscopy resolution. We have demonstrated the application of near-field scanning optical microscopy to DNA samples and opened the new fields of near-field scanning spectroscopy and submicron opto- chemical sensors. All of these developments have been important steps towards in-situ DNA imaging and characterization on the nanoscale. Our first goal was to make NSOM (near-field scanning optical microscopy) a working enterprise, capable of ``zooming-in`` towards a sample and imaging with a resolution exceeding that of traditional microscopy by a factor of ten. This has been achieved. Not only do we have a resolution of about 40 nm but we can image a 1 {times} 1 micron object in less than 10 seconds. Furthermore, the NSOM is a practical instrument. The tips survive for days or weeks of scanning and new methods of force feedback will soon protect the most fragile samples. Reproducible images of metal gratings, gold particles, dye balls (for calibration) and of several DNA samples have been made, proving the practicality of our approach. We also give highly resolved Force/NSOM images of human blood cells. Our second goal has been to form molecular optics (e.g., exciton donor) tips with a resolution of 2--10 nm for molecular excitation microscopy (MEM). We have produced such tips, and scanned with them, but only with a resolution comparable to that of our standard NSOM tips. However, we have demonstrated their potential for high resolution imaging capabilities: (1) An energy transfer (tip to sample) based feedback capability. (2) A Kasha (external heavy atom) effect based feedback. In addition, a novel and practical opto-chemical sensor that is a billion times smaller than the best ones available has been developed as well. Finally, we have also performed spatially resolved fluorescence spectroscopy.

  7. Civil liability and compensation for damages caused by certain hazardous and noxious substances during their carriage by sea

    International Nuclear Information System (INIS)

    In this paper current international efforts directed at the establishment of a special legal regime for civil liability and compensation for damages caused by hazardous and noxious substances during their transport by sea, specifically chemicals and liquid gas products, are described and analysed. Special attention is given to the way in which concern with the development of an 'environment oriented' regime which provides full recovery for victims in a reliable manner, on the one hand, and, on the other, considerations relating to cost effectiveness complement or conflict with each other. Another important area of investigation concerns the potential role of the marine insurance industry in accident prevention through the provision of incentives for careful (i.e. safe and environmentally sound) behaviour. There is a distinct regulatory trend in favour of strict liability (i.e. liability without fault) and compulsory insurance. There is also a growing perception of the need to depart from the traditional pattern of maritime liability which channels liability automatically to the person exercizing operational control during transport by sea (i.e. the carrier), and to additionally impose liability on those responsible for the risks attached to the inherently harmful characteristics of the cargoes carried. (orig.)

  8. Speciation of aquatic Hg2+ in humic substances by time differential perturbed angular correlation

    International Nuclear Information System (INIS)

    Humic substances are ubiquitous in waters and soils and act as complexing agents for different heavy metals, e.g. Cd, Hg. Toxicity, reactivity, fixation, and migration are therefore strongly influenced by the interactions between heavy metals and humic substances. Humic substances derive from postmortal materials such as rotten plants, have dark colours and usually a molecular weight between 500 and 10.000 Dalton. Complex formation studies with different heavy metal ions indicate at least two different kinds of metal sites. Usually, these studies are restricted to heavy metal concentrations 2 to 3 orders of magnitude higher that the natural heavy metal abundance (i.e. 10-10 molar). This serious limitation can be overcome by the use of suitable radioisotope techniques capable of metal speciation at extreme sensitivity levels such as TDPAC (Time Differential Perturbed Angular Correlation of γ-Rays). Thus, we studied the interaction of heavy metals with humic substances by monitoring the nuclear quadrupole interaction (NQI)of the short-lived radioisotopes 111mCd (τl/2 = 49 min) and 199mHg (τ1/2 = 43 min) supplied by ISOLDE via γ-γ -TDPAC and compared the 111mCd/199mHg-NQIs in humic substances with the known NQI of model compounds (i.e. metal proteins, organometallic compounds). At lowest Hg(II) concentrations (10-10 molar) only linear Hg(ll) coordinations with nitrogen and/or sulfur were observed, with increasing Hg(II) concentration additional distorted trigonal (at 2.5.10-10 molar) and tetrahedral coordinations (at 2.5.10-8 molar) with various ligands show up and start to become dominant at Hg(II) concentrations of 10-7 molar and higher. Contrary to Hg(II), we observed unspecific binding for Cd(lI) in the 111mCd-TDPAC experiments only, even in the 10-10 molar concentration range

  9. Recommendations on chemicals management policy and legislation in the framework of the Egyptian-German twinning project on hazardous substances and waste management.

    Science.gov (United States)

    Wagner, Burkhard O; Aziz, Elham Refaat Abdel; Schwetje, Anja; Shouk, Fatma Abou; Koch-Jugl, Juliane; Braedt, Michael; Choudhury, Keya; Weber, Roland

    2013-04-01

    The sustainable management of chemicals and their associated wastes-especially legacy stockpiles-is always challenging. Developing countries face particular difficulties as they often have insufficient treatment and disposal capacity, have limited resources and many lack an appropriate and effective regulatory framework. This paper describes the objectives and the approach of the Egyptian-German Twinning Project under the European Neighbourhood Policy to improve the strategy of managing hazardous substances in the Egyptian Environmental Affairs Agency (EEAA) between November 2008 and May 2011. It also provides an introduction to the Republic of Egypt's legal and administrative system regarding chemical controls. Subsequently, options for a new chemical management strategy consistent with the recommendations of the United Nations Chemicals Conventions are proposed. The Egyptian legal and administrative system is discussed in relation to the United Nations' recommendations and current European Union legislation for the sound management of chemicals. We also discuss a strategy for the EEAA to use the existing Egyptian legal system to implement the United Nations' Globally Harmonized System of Classification and Labelling of Chemicals, the Stockholm Convention and other proposed regulatory frameworks. The analysis, the results, and the recommendations presented may be useful for other developing countries in a comparable position to Egypt aspiring to update their legislation and administration to the international standards of sound management of chemicals. PMID:23417361

  10. Synthesis and Characterization of Chemically Cross-Linked Acrylic Acid/Gelatin Hydrogels: Effect of pH and Composition on Swelling and Drug Release

    Directory of Open Access Journals (Sweden)

    Syed Majid Hanif Bukhari

    2015-01-01

    Full Text Available This present work was aimed at synthesizing pH-sensitive cross-linked AA/Gelatin hydrogels by free radical polymerization. Ammonium persulfate and ethylene glycol dimethacrylate (EGDMA were used as initiator and as cross-linking agent, respectively. Different feed ratios of acrylic acid, gelatin, and EGDMA were used to investigate the effect of monomer, polymer, and degree of cross-linking on swelling and release pattern of the model drug. The swelling behavior of the hydrogel samples was studied in 0.05 M USP phosphate buffer solutions of various pH values pH 1.2, pH 5.5, pH 6.5, and pH 7.5. The prepared samples were evaluated for porosity and sol-gel fraction analysis. Pheniramine maleate used for allergy treatment was loaded as model drug in selected samples. The release study of the drug was investigated in 0.05 M USP phosphate buffer of varying pH values (1.2, 5.5, and 7.5 for 12 hrs. The release data was fitted to various kinetic models to study the release mechanism. Hydrogels were characterized by Fourier transformed infrared (FTIR spectroscopy which confirmed formation of structure. Surface morphology of unloaded and loaded samples was studied by surface electron microscopy (SEM, which confirmed the distribution of model drug in the gel network.

  11. Quantitative structure activity relationship model for predicting the depletion percentage of skin allergic chemical substances of glutathione.

    Science.gov (United States)

    Si, Hongzong; Wang, Tao; Zhang, Kejun; Duan, Yun-Bo; Yuan, Shuping; Fu, Aiping; Hu, Zhide

    2007-05-22

    A quantitative model was developed to predict the depletion percentage of glutathione (DPG) compounds by gene expression programming (GEP). Each kind of compound was represented by several calculated structural descriptors involving constitutional, topological, geometrical, electrostatic and quantum-chemical features of compounds. The GEP method produced a nonlinear and five-descriptor quantitative model with a mean error and a correlation coefficient of 10.52 and 0.94 for the training set, 22.80 and 0.85 for the test set, respectively. It is shown that the GEP predicted results are in good agreement with experimental ones, better than those of the heuristic method. PMID:17481417

  12. Zn Adsorption by Variable Charge Soils in Relation to pH

    Institute of Scientific and Technical Information of China (English)

    SUNHAN-YUAN

    1993-01-01

    Zn adsorption by pure oxides or in the presence of a high concentration of inner electrolyte has been extensively studied.But,in studies on Zn adsorption in the complicated soil system,especially in variable charge soils,profound knowledge about the absorption mechanism still lacks.In this paper,taking Zn ion adsorption by two typical variable charge soils as the object of the study,author discusses the relation between Zn adsorption and pH and possible adsorption mechanisms.The results showed that in the low pH range where the amount of Zn adsorbed did not exceed 50% of Zn added,the specific adsorption was the diminant mechanism.The species of Zn specifically adsorbed was free Zn2+ ion.In the middle and high pH ranges,the mechanisms of specific and electrostatic adsorptions co-existed,accounting for about 70% and 30%,respectively.Noteworthily,in the high pH range,the hydroxyl Zn ion (ZnOH+) from Zn2+ hydrolysis probably was a preferable species for specific absorption.

  13. Electrochemical remediation of copper contaminated kaolinite by conditioning anolyte and catholyte pH simultaneously

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This report examined electrochemical remediation of copper contaminated kaolinite by controlling electrolytes' pH for both of anolyte and catholyte simultaneously. Results showed that electrokinetic process and remediation efficiency varied obviously when different buffer systems, including citric acid (test 1), nitric acid + EDTA (test 2) and nitric acid (test 3), were used to control catholyte pH and Na2CO3 was used at the same time to control all anolyte one. It was found that under such pH condition soil's pH in soil column kept at 3.0-7.0 successfully, and correspondingly no copper precipitation and decrease of soil electroconductivity appeared, which are usually observed in electrokinetic process due to OH- introduction into soil column by electrochemical reaction occurred in cathode. Electroosmosis flow rates were almost equal for these three tests, indicating that these buffers did not affect Zeta-potential of kaolinite within the examined duration. More acid and basic solution was added into electrokinetic cell when nitric acid was used as buffer than when nitric acid + EDTA and then citric acid were used. Due to introduction of large amounts of ions into soil column, significant higher current was observed for test 3 than other two. Analysis of copper speciation and total quantity in kaolinite indicated that 55.65%, 22.5% and 23.74% Cu were removed from kaolinite for test 1, test 2 and test 3 respectively after only 10 days' electrokinetic remediation.

  14. PREDICTING CHEMICAL REACTIVITY OF HUMIC SUBSTANCES FOR MINERALS AND XENOBIOTICS: USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY AND VIRTUAL REALITY

    Science.gov (United States)

    In this chapter we review the literature on scanning probe microscopy (SPM), virtual reality (VR), and computational chemistry and our earlier work dealing with modeling lignin, lignin-carbohydrate complexes (LCC), humic substances (HSs) and non-bonded organo-mineral interactions...

  15. Biodegradation of beet molasses vinasse by a mixed culture of micro organisms: Effect of aeration conditions and pH control

    Institute of Scientific and Technical Information of China (English)

    Krzysztof Lutoslawski; Agnieszka Ryznar-Luty; Edmund Cibis; Malgorzata Krzywonos; Tadeusz Mi(s)kiewicz

    2011-01-01

    The effect of aeration conditions and pH control on the progress and efficiency of beet molasses vinasse biodegradation was investigated during four batch processes at 38℃ with the mixed microbial culture composed of Bifidobacterium,Lactobacillus,Lactococcus,Streptococcus,Bacillus,Rhodopseudomonas,and Saccharomyces.The four processes were carried out in a shake flask with no pH control,an aerobic bioreactor without mixing with no pH control,and a stirred-tank reactor (STR) with aeration with and without pH control,respectively.All experiments were started with an initial pH 8.0.The highest efficiency of biodegradation was achieved through the processes conducted in the STR,where betaine (an organic pollutant occurring in beet molasses in very large quantities) was completely degraded by the microorganisms.The process with no pH control carried out in the STR produced the highest reduction in the following pollution measures:organic matter expressed as chemical oxygen demand determined by the dichromatic method + theoretical COD of betaine (CODsum,85.5%),total organic carbon (TOC,78.8%) and five-day biological oxygen demand (BOD5,98.6%).The process conditions applied in the shake flask experiments,as well as those used in the aerobic bioreactor without mixing,failed to provide complete betaine assimilation.As a consequence,reduction in CODwum,TOC and BOD5 was approximately half that obtained with STR.

  16. Variations in clubbers' substance use by individual and scene-level factors.

    Science.gov (United States)

    Anderson, Tammy L; Kavanaugh, Philip R; Rapp, Laura; Daly, Kevin

    2009-01-01

    Research on clubbing spans numerous fields and adopts diverse approaches to the populations in question. Yet, a somewhat homogenous narrative has emerged about clubbers and substance use, one that focuses on overconsumption, risky behavior, and considerable consequence. The purpose of our study is to unpack this narrative by exploring how the substance use patterns of clubbing populations differ by individual and scene-level factors. From this, we hope to increase an understanding of how social and cultural factors impact the relationship between clubbers and substance use. We draw on direct observation of 29 club events and interviews with 51 respondents from the hip hop (HH) and electronic dance music (EDM) scenes in Philadelphia to inform our research objective. Analyses revealed two broad criteria on which a substance use-based typology of clubbers can be offered: motivations for clubbing and level and type of scene involvement. From these two dimensions, we are able to distinguish among three types of clubbers: drug sub-cultural members, commercial clubbers, and music connoisseurs. Drug sub-cultural members reported early onset of drug use and a greater frequency of current drug use at largely underground EDM club events and outside them as well. Commercial clubbers had benign histories with drugs, but they reported attending mostly commercialized HH events to get drunk and court the opposite sex. Music connoisseurs reported minimal current drug and alcohol use at exclusively underground EDM and HH club events, following from, in some cases, extensive histories with drugs and alcohol. The differences between these three groups' substance use patterns, we contend, can be attributed to the interplay between numerous social and cultural factors not previously considered. PMID:20011988

  17. Projected pH reductions by 2100 might put deep North Atlantic biodiversity at risk

    Science.gov (United States)

    Gehlen, M.; Séférian, R.; Jones, D. O. B.; Roy, T.; Roth, R.; Barry, J.; Bopp, L.; Doney, S. C.; Dunne, J. P.; Heinze, C.; Joos, F.; Orr, J. C.; Resplandy, L.; Segschneider, J.; Tjiputra, J.

    2014-12-01

    This study aims to evaluate the potential for impacts of ocean acidification on North Atlantic deep-sea ecosystems in response to IPCC AR5 Representative Concentration Pathways (RCPs). Deep-sea biota is likely highly vulnerable to changes in seawater chemistry and sensitive to moderate excursions in pH. Here we show, from seven fully coupled Earth system models, that for three out of four RCPs over 17% of the seafloor area below 500 m depth in the North Atlantic sector will experience pH reductions exceeding -0.2 units by 2100. Increased stratification in response to climate change partially alleviates the impact of ocean acidification on deep benthic environments. We report on major pH reductions over the deep North Atlantic seafloor (depth >500 m) and at important deep-sea features, such as seamounts and canyons. By 2100, and under the high CO2 scenario RCP8.5, pH reductions exceeding -0.2 (-0.3) units are projected in close to 23% (~15%) of North Atlantic deep-sea canyons and ~8% (3%) of seamounts - including seamounts proposed as sites of marine protected areas. The spatial pattern of impacts reflects the depth of the pH perturbation and does not scale linearly with atmospheric CO2 concentration. Impacts may cause negative changes of the same magnitude or exceeding the current target of 10% of preservation of marine biomes set by the convention on biological diversity, implying that ocean acidification may offset benefits from conservation/management strategies relying on the regulation of resource exploitation.

  18. Projected pH reductions by 2100 might put deep North Atlantic biodiversity at risk

    Directory of Open Access Journals (Sweden)

    M. Gehlen

    2014-06-01

    Full Text Available This study aims at evaluating the potential for impacts of ocean acidification on North Atlantic deep-sea ecosystems in response to IPCC AR5 Representative Concentration Pathways (RCP. Deep-sea biota is likely highly vulnerable to changes in seawater chemistry and sensitive to moderate excursions in pH. Here we show, from seven fully-coupled Earth system models, that for three out of four RCPs over 17% of the seafloor area below 500 m depth in the North Atlantic sector will experience pH reductions exceeding −0.2 units by 2100. Increased stratification in response to climate change partially alleviates the impact of ocean acidification on deep benthic environment. We report major potential consequences of pH reductions for deep-sea biodiversity hotspots, such as seamounts and canyons. By 2100 and under the high CO2 scenario RCP8.5 pH reductions exceeding −0.2, (respectively −0.3 units are projected in close to 23% (~ 15% of North Atlantic deep-sea canyons and ~ 8% (3% of seamounts – including seamounts proposed as sites of marine protected areas. The spatial pattern of impacts reflects the depth of the pH perturbation and does not scale linearly with atmospheric CO2 concentration. Impacts may cause negative changes of the same magnitude or exceeding the current target of 10% of preservation of marine biomes set by the convention on biological diversity implying that ocean acidification may offset benefits from conservation/management strategies relying on the regulation of resource exploitation.

  19. Direct measurement of the fluorescence characteristics of aquatic humic substances by a three-dimensional fluorescence spectrophotometer

    International Nuclear Information System (INIS)

    Humic substances play an important role in the transport of trace metals and insoluble organic materials. They are also considered to be precursors of trihalomethane in aquatic environments. The direct measurement of humic substances was carried out with a three-dimensional fluorescence spectrophotometer after filtering natural-water samples through a GF/F glass fiber filter. Because the influence of the humic concentration, pH and ionic strength on the three-dimensional excitation emission matrix spectra is negligible, the proposed method can be directly applied to the characterization of humic substances in freshwater samples (humic concentration 0.5-10 mg 1-1, pH6-9 and ionic strength <0.04 M) and sea-water samples (ionic strength 0.75 M). Humic substances in river, lake and pore water samples exhibit 2-3 peaks at excitation 305-340 nm/emission 415-440 nm and excitation 250-270 nm/emission 440-450 nm. These peak positions correspond to those of fulvic acids isolated from soil. (author)

  20. Darcys Law Expressed by Chemical Index

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Darcys formula expressed by chemical indexes (ion activity a and saturation index f) is derived with the aid of the kinetics of multi-mineral dissolution. The implication of the formula and the relationship between the formula and the original Darcy′s law expressed by hydraulic index (hydraulic gradient, I ) are discussed here. An analytic expression is established in this paper for the determination of the residence time of groundwater by chemical indexes, whose equivalence to isotopic age is studled. The formulas are derived from the calculation of permeability coefficient (K), conductivity coefficient (T) and actual velocity of groundwater (U). Finally, this paper introduces hydrogeological chemical kinetics constant (kj) and its determination method, differential and integral equations for chemical kinetics of groundwater in three-dimensional space.

  1. δ15N measurement of organic and inorganic substances by EA-IRMS: a speciation-dependent procedure.

    Science.gov (United States)

    Gentile, Natacha; Rossi, Michel J; Delémont, Olivier; Siegwolf, Rolf T W

    2013-01-01

    Little attention has been paid so far to the influence of the chemical nature of the substance when measuring δ(15)N by elemental analysis (EA)-isotope ratio mass spectrometry (IRMS). Although the bulk nitrogen isotope analysis of organic material is not to be questioned, literature from different disciplines using IRMS provides hints that the quantitative conversion of nitrate into nitrogen presents difficulties. We observed abnormal series of δ(15)N values of laboratory standards and nitrates. These unexpected results were shown to be related to the tailing of the nitrogen peak of nitrate-containing compounds. A series of experiments were set up to investigate the cause of this phenomenon, using ammonium nitrate (NH(4)NO(3)) and potassium nitrate (KNO(3)) samples, two organic laboratory standards as well as the international secondary reference materials IAEA-N1, IAEA-N2-two ammonium sulphates [(NH(4))(2)SO(4)]-and IAEA-NO-3, a potassium nitrate. In experiment 1, we used graphite and vanadium pentoxide (V(2)O(5)) as additives to observe if they could enhance the decomposition (combustion) of nitrates. In experiment 2, we tested another elemental analyser configuration including an additional section of reduced copper in order to see whether or not the tailing could originate from an incomplete reduction process. Finally, we modified several parameters of the method and observed their influence on the peak shape, δ(15)N value and nitrogen content in weight percent of nitrogen of the target substances. We found the best results using mere thermal decomposition in helium, under exclusion of any oxygen. We show that the analytical procedure used for organic samples should not be used for nitrates because of their different chemical nature. We present the best performance given one set of sample introduction parameters for the analysis of nitrates, as well as for the ammonium sulphate IAEA-N1 and IAEA-N2 reference materials. We discuss these results considering the

  2. Influence of ph on corrosion control of carbon steel by peroxide injection in sour water

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Martins Magda; Baptista, Walmar; Joia, Carlos Jose Bandeira de Mello [PROTEMP - PETROBRAS/CENPES, Cidade Universitaria, Quadra 7, Rio de Janeiro, CEP 21949-900 (Brazil); Ponciano, Gomes Jose Antonio da Cunha [Departamento de Engenharia Metalurgica e de Materiais-COPPE/UFRJ, Cidade Universitaria, Rio de Janeiro (Brazil)

    2004-07-01

    Sour hydrogen damage is considered the most important corrosive process in the light-ends recovery section of Fluid Catalytic Cracking Units (FCCU). Corrosion in this condition is due to heavy gas oil that originates great amount of contaminants, such as H{sub 2}S, NH{sub 3} and HCN. Hydrogen absorption is promoted by the presence of free cyanides in the environment. The attenuation of this process requires the use of some inhibitors, such as oxygen, hydrogen peroxide (H{sub 2}O{sub 2}) or commercial polysulfides. The effect of these compounds is to neutralize free cyanides (CN{sup -}) into thio-sulfides (SCN{sup -}). When peroxide injection is selected, cyanide concentration in sour water has been used as key parameter to start the peroxide introduction. However, the importance of pH in this system has been pointed out by many authors. The aim of this work is to investigate the influence of pH when peroxide injection is carried out in less alkaline conditions of sour water. Electrochemical techniques - like anodic polarization and hydrogen permeation tests - and weight loss measurements were used to evaluate the effectiveness of corrosion control of carbon steel. It was concluded that at pH 7.5 peroxide injection can drive to an increment of the corrosion rate. Besides that, it was concluded that hydrogen permeation into the metal is promoted. Both detrimental effects were due to elemental sulfur generation in this pH range. The adoption of pH as a key parameter for peroxide injection is then suggested. (authors)

  3. Prediction of standard chemical exergy by a three descriptors QSPR model

    International Nuclear Information System (INIS)

    A new quantitative structure-property relationship (QSPR) three parameter correlation (R 2 = 0.9977) of standard chemical exergy for a diverse set of 134 organic substances was developed by application of a genetic algorithm search. The descriptors are all calculated directly from the molecular structure, and the approach given is applicable, in principle, to all organic substances of regular structure. The application of the genetic algorithm in comparison with stepwise multi-variate linear regression (MLR) shows some advantages in required time for solving and in precision

  4. Effects of Immunomodulatory Substances on Phagocytosis of Aβ 1–42 by Human Microglia

    OpenAIRE

    Marianne Schultzberg; Dan Frenkel; Howard Weiner; Erik Hjorth

    2010-01-01

    Glial activation and increased inflammation characterize neuropathology in Alzheimer's disease (AD). The aim was to develop a model for studying phagocytosis of β-amyloid (Aβ) peptide by human microglia and to test effects thereupon by immunomodulatory substances. Human CHME3 microglia showed intracellular Aβ1–42 colocalized with lysosome-associated membrane protein-2, indicating phagocytosis. This was increased by interferon-γ, and to a lesser degree wit...

  5. Protection of cells from salinity stress by extracellular polymeric substances in diatom biofilms

    OpenAIRE

    Steele, Deborah J.; Franklin, Daniel J.; Underwood, Graham J.C.

    2014-01-01

    Diatom biofilms are abundant in the marine environment. It is assumed (but untested) that extracellular polymeric substances (EPS), produced by diatoms, enable cells to cope with fluctuating salinity. To determine the protective role of EPS, Cylindrotheca closterium was grown in xanthan gum at salinities of 35, 50, 70 and 90 ppt. A xanthan matrix significantly increased cell viability (determined by SYTOX-Green), growth rate and population density by up to 300, 2,300 and 200%, respectively. D...

  6. Influence of the initial ph of sugar cane juice on the production of levan by Zymomonas mobilis ATCC 31821

    Directory of Open Access Journals (Sweden)

    Marcia Sadae Tano

    2002-01-01

    Full Text Available The influence of initial pH of sugar cane juice in high concentration was investigated for levan production by Zymomonas mobilis. In the initial pH of medium of 5.4; 5.9 and 6..3 the levan concentration achieved 1.66; 2.54 and 3.83 g/L, respectively, in 48 hours of fermentation. The final levan concentration in the initial pH of 6.3 and 5.9 increased 130 and 53% when compared to concentration at initial pH 5.4 in the medium. The levan yield at pH 5.9 was 87.5% and at pH 6.3 was 162.5% superior in relation to that obtained at initial pH 5.4.

  7. Fermentation, fractionation and purification of streptokinase by chemical reduction method

    Directory of Open Access Journals (Sweden)

    M Niakan

    2011-05-01

    Full Text Available Background and Objectives: Streptokinase is used clinically as an intravenous thrombolytic agent for the treatment of acute myocardial infarction and is commonly prepared from cultures of Streptococcus equisimilis strain H46A. The objective of the present study was the production of streptokinase from strain H46A and purification by chemical reduction method."nMaterials and Methods: The rate of streptokinase production evaluated under the effect of changes on some fermentation factors. Moreover, due to the specific structure of streptokinase, a chemical reduction method employed for the purification of streptokinase from the fermentation broth. The H46A strain of group C streptococcus, was grown in a fermentor. The proper pH adjusted with NaOH under glucose feeding in an optimum temperature. The supernatant of the fermentation product was sterilized by filtration and concentrated by ultrafiltration. The pH of the concentrate was adjusted, cooled, and precipitated by methanol. Protein solution was reduced with dithiothreitol (DTT. Impurities settled down by aldrithiol-2 and the biological activity of supernatant containing streptokinase was determined."nResults: In the fed -batch culture, the rate of streptokinase production increased over two times as compared with the batch culture and the impurities were effectively separated from streptokinase by reduction method."nConclusion: Improvements in SK production are due to a decrease in lag phase period and increase in the growth rate of logarithmic phase. The methods of purification often result in unacceptable losses of streptokinase, but the chemical reduction method give high yield of streptokinase and is easy to perform it.

  8. Evaluation of the protective effect of chemical additives in the oxidation of phenolic compounds catalysed by peroxidase.

    Science.gov (United States)

    Torres, Juliana Arriel; Chagas, Pricila Maria Batista; Silva, Maria Cristina; Dos Santos, Custódio Donizete; Corrêa, Angelita Duarte

    2016-01-01

    The use of oxidoredutive enzymes in removing organic pollutants has been the subject of much research. The oxidation of phenolic compounds in the presence of chemical additives has been the focus of this study. In this investigation, the influence of the additives polyethylene glycol and Triton X-100 was evaluated in the phenol oxidation, caffeic acid, chlorogenic acid and total phenolic compounds present in coffee processing wastewater (CPW) at different pH values, performed by turnip peroxidase and peroxidase extracted from soybean seed hulls. The influence of these additives was observed only in the oxidation of phenol and caffeic acid. In the oxidation of other studied phenolic compounds, the percentage of oxidation remained unchanged in the presence of these chemical additives. In the oxidation of CPW in the presence of additives, no change in the oxidation of phenolic compounds was observed. Although several studies show the importance of evaluating the influence of additives on the behaviour of enzymes, this study found a positive response from the economic point of view for the treatment of real wastewater, since the addition of these substances showed no influence on the oxidation of phenolic compounds, which makes the process less costly. PMID:26502790

  9. Chemical sensor

    Science.gov (United States)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  10. 21 CFR 1300.04 - Definitions relating to the dispensing of controlled substances by means of the Internet.

    Science.gov (United States)

    2010-04-01

    ... controlled substances by means of the Internet. 1300.04 Section 1300.04 Food and Drugs DRUG ENFORCEMENT... substances by means of the Internet. (a) Any term not defined in this part or elsewhere in this chapter shall have the definition set forth in sections 102 and 309 of the Act (21 U.S.C. 802, 829). (b) The...

  11. Silicon Sheets By Redox Assisted Chemical Exfoliation

    CERN Document Server

    Tchalala, Mohamed Rachid; Enriquez, Hanna; Kara, Abdelkader; Lachgar, Abdessadek; Yagoubi, Said; Foy, Eddy; Vega, Enrique; Bendounan, Azzedine; Silly, Mathieu G; Sirotti, Fausto; Nitshe, Serge; Chaudanson, Damien; Jamgotchian, Haik; Aufray, Bernard; Mayne, Andrew J; Dujardin, Gérald; Oughaddou, Hamid

    2013-01-01

    In this paper, we report the direct chemical synthesis of silicon sheets in gram-scale quantities by chemical exfoliation of pre-processed calcium di-silicide (CaSi2). We have used a combination of X-ray photoelectron spectroscopy, transmission electron microscopy and Energy-dispersive X-ray spectroscopy to characterize the obtained silicon sheets. We found that the clean and crystalline silicon sheets show a 2-dimensional hexagonal graphitic structure.

  12. pH and temperature effects on the molecular conformation of the porcine pancreatic secretory trypsin inhibitor as detected by hydrogen-1 nuclear magnetic resonance

    International Nuclear Information System (INIS)

    1H NMR spectra of the porcine pancreatic secretory trypsin inhibitor (PSTI) have been recorded vs. pH and temperature. Of the two tyrosines, one titrates with a pK of 1.25, while the resonances from the other are pH insensitive in the investigated range 4.8 less than or equal to pH less than or equal to 12. This is consistent with PSTI having one Tyr solvent exposed (Try-20) and the other buried (Tyr-31). The resonances from the lysyl epsilon-CH2 protons titrate with a pK of 10.95. The titration is accompanied by a pronounced line broadening, which starts near pH 8.5. Between pH 11.5 and pH 12 the epsilon-CH2 resonances recover their low pH line width. Titration curves for the lysines and Tyr-20 reflect single proton ionization equilibria, suggesting that these residues do not interact among themselves. On the basis of double resonance experiments, combined with analysis of chemical shifts, spin-spin couplngs, and line widths, all methyl resonances are identified and followed as functions of pH and temperature. The γ-CH3 doublet from the N-terminal Thr-1 is assigned by comparison between spectra of forms I and II of the inhibitor, the latter lacking the first four residues of form I. The β-CH3 resonance from Ala-7 is also assigned. Proton resonance parameters of methyl groups are shown to afford useful NMR probes for the characterization of local nonbonded interactions, microenvironments, and mobilities

  13. Antibiotic Bactericidal Activity Is Countered by Maintaining pH Homeostasis in Mycobacterium smegmatis.

    Science.gov (United States)

    Bartek, I L; Reichlen, M J; Honaker, R W; Leistikow, R L; Clambey, E T; Scobey, M S; Hinds, A B; Born, S E; Covey, C R; Schurr, M J; Lenaerts, A J; Voskuil, M I

    2016-01-01

    Antibiotics target specific biosynthetic processes essential for bacterial growth. It is intriguing that several commonalities connect the bactericidal activity of seemingly disparate antibiotics, such as the numerous conditions that confer broad-spectrum antibiotic tolerance. Whether antibiotics kill in a manner unique to their specific targets or by a universal mechanism is a critical and contested subject. Herein, we demonstrate that the bactericidal activity of diverse antibiotics against Mycobacterium smegmatis and four evolutionarily divergent bacterial pathogens was blocked by conditions that worked to maintain intracellular pH homeostasis. Single-cell pH analysis demonstrated that antibiotics increased the cytosolic pH of M. smegmatis, while conditions that promoted proton entry into the cytosol prevented intracellular alkalization and antibiotic killing. These findings led to a hypothesis that posits antibiotic lethality occurs when antibiotics obstruct ATP-consuming biosynthetic processes while metabolically driven proton efflux is sustained despite the loss of proton influx via ATP synthase. Consequently, without a concomitant reduction in respiratory proton efflux, cell death occurs due to intracellular alkalization. Our findings indicate the effects of antibiotics on pH homeostasis should be considered a potential mechanism contributing to antibiotic lethality. IMPORTANCE Since the discovery of antibiotics, mortality due to bacterial infection has decreased dramatically. However, infections from difficult to treat bacteria such as Mycobacterium tuberculosis and multidrug-resistant pathogens have been on the rise. An understanding of the cascade of events that leads to cell death downstream of specific drug-target interactions is not well understood. We have discovered that killing by several classes of antibiotics was stopped by maintaining pH balance within the bacterial cell, consistent with a shared mechanism of antibiotic killing. Our findings

  14. Regularities of polymer substances transformation into methane by thermophilic anaerobic bacteria

    OpenAIRE

    V. І. Karpenko; L. S. Yastremska; І. G. Burun; Y. V. Lembey; O. S. Tatarchenko

    2006-01-01

    The paper shows the regularities of polymer substances transformation into methane by extracted thermophilic anaerobic bacteria. The sequence of substrate use by the methane generating bacteria corresponds to the energy efficiency of the methane genesis reactions as in the first place hydrogen is used and then acetate is. Combined cultivation of extracted different anaerobic cultures gives the opportunity to increase ethanol and hydrogen yield as well as the effectiveness of methane formation.

  15. Anaerobic decomposition of humic substances by Clostridium from the deep subsurface

    OpenAIRE

    Akio Ueno; Satoru Shimizu; Shuji Tamamura; Hidetoshi Okuyama; Takeshi Naganuma; Katsuhiko Kaneko

    2016-01-01

    Decomposition of humic substances (HSs) is a slow and cryptic but non-negligible component of carbon cycling in sediments. Aerobic decomposition of HSs by microorganisms in the surface environment has been well documented; however, the mechanism of anaerobic microbial decomposition of HSs is not completely understood. Moreover, no microorganisms capable of anaerobic decomposition of HSs have been isolated. Here, we report the anaerobic decomposition of humic acids (HAs) by the anaerobic bacte...

  16. Influence of humic substances on Co[sup 2+] sorption by a subsurface mineral separate and its mineralogic components

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, J.M.; Resch, C.T.; Smith, S.C. (Pacific Northwest Laboratory, Richland, WA (United States))

    1994-01-01

    The sorption of Co[sup 2+] (10[sup [minus]6] mol/L) was measured on subsurface mineral materials in the absence and presence of a sorbed leonardite humic acid (LHA) to (1) evaluate the sorptive role of mineral-bound humic substances, and (2) establish approaches to model metal ion binding in composite materials. The subsurface materials were a <2.0 [mu]m size fraction of an ultisol saprolite (CP) and this same material treated with dithonite-citrate-bicarbonate (DCB) to remove Fe-oxides (DCP). Comparable experiments (with and without LHA) were also performed with mineral sorbents representing dominant phases in the CP separate (gibbsite, Al-geothite, and kalonite) to evaluate their potential contributions to Co sorption. The mineral-bound LHA ranged in concentration between 0.1-0.4 mg-C/m[sup 2], representing approximately 0.7% of the subsurface isolate by mass. In solid-free suspensions, the affinity of LHA for Co increased with pH and decreasing I (K[sub d] ranging 20-450 L/g). Mineral-bound LHA increased Co sorption on all the sorbents by factors of 10-60%, with the greatest augmentation noted at pH values (4.5-6.5) where (1) maximum LHA sorption occurred, and (2) Co sorption to the mineral phase was weak and dominated by ion exchange. The LHA appeared simply to augment, rather than to change the intrinsic adsorption behavior of the mineral sorbents. Accordingly, predictions of the K[sub d] for Co on the LHA-coated subsurface materials (DCP, CP) based on a linear additivity model agreed well with the experimental data, suggesting that the complex humic-mineral association acted as a noninterative sorbent mixture at low aqueous Co concentrations.

  17. Chitosan nanoparticles crosslinked by glycidoxypropyltrimethoxysilane for pH triggered release of protein

    Institute of Scientific and Technical Information of China (English)

    Ai Wu Pan; Bei Bei Wu; Jian Min Wu

    2009-01-01

    pH-responsive-chitosan nanoparticles for the control release of protein drug were prepared by combining two-step crosslinking method, in which chitosan was subsequently crosslinked by sodium tripolyphosphate (TPP) and glycidoxypropyltrimethoxysilane (GPTMS). Compared with TPP crosslinked chitosan particles, the two-step crosslinked nanoparticles were not only pH-responsive but also more stable in wide pH range. Fluorescein isothiocyanate (FITC) labeled anti-human-IgG antibody was used as a model protein drug for evaluating the control release profile of the nano-carrier. The amount of released antibody increased from 5.6% to 50% when the pH of solution shifted from 7.4 m 6.0. The results suggest the possible application of the nanoparticles as pH-responsive drug delivery materials.

  18. Nano-sized ZnO powders prepared by co-precipitation method with various pH

    Science.gov (United States)

    Purwaningsih, S. Y.; Pratapa, S.; Triwikantoro, Darminto

    2016-04-01

    In this work, nano-sized ZnO powders have been synthesized by the co-precipitation method with Zn(CH3COOH)2.2H2O, HCl, and NH3.H2O as raw materials in various pH ranging from 8 to 10. The purity, microstructure, chemical group analysis, morphology of the prepared ZnO powders were studied by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), energy dispersive X-ray spectrometry (EDX), and scanning electron microscope (SEM), respectively. Rietveld refinement of XRD data showed that ZnO crystallizes in the wurtzite structure with high purity. The obtained powders were nano-sized particles with the average crystallite size about 17.9 ± 2.1 nm synthesized with pH of 9.5, at 85°C, and stirring time of 6 h. The SEM results have visualied the morphology of ZnO nanoparticles with spherical-like shape. The effect of processing conditions on morphology of ZnO was also discussed.

  19. Predicting Anatomical Therapeutic Chemical (ATC classification of drugs by integrating chemical-chemical interactions and similarities.

    Directory of Open Access Journals (Sweden)

    Lei Chen

    Full Text Available The Anatomical Therapeutic Chemical (ATC classification system, recommended by the World Health Organization, categories drugs into different classes according to their therapeutic and chemical characteristics. For a set of query compounds, how can we identify which ATC-class (or classes they belong to? It is an important and challenging problem because the information thus obtained would be quite useful for drug development and utilization. By hybridizing the informations of chemical-chemical interactions and chemical-chemical similarities, a novel method was developed for such purpose. It was observed by the jackknife test on a benchmark dataset of 3,883 drug compounds that the overall success rate achieved by the prediction method was about 73% in identifying the drugs among the following 14 main ATC-classes: (1 alimentary tract and metabolism; (2 blood and blood forming organs; (3 cardiovascular system; (4 dermatologicals; (5 genitourinary system and sex hormones; (6 systemic hormonal preparations, excluding sex hormones and insulins; (7 anti-infectives for systemic use; (8 antineoplastic and immunomodulating agents; (9 musculoskeletal system; (10 nervous system; (11 antiparasitic products, insecticides and repellents; (12 respiratory system; (13 sensory organs; (14 various. Such a success rate is substantially higher than 7% by the random guess. It has not escaped our notice that the current method can be straightforwardly extended to identify the drugs for their 2(nd-level, 3(rd-level, 4(th-level, and 5(th-level ATC-classifications once the statistically significant benchmark data are available for these lower levels.

  20. 应用高效液相色谱法测定缬沙坦氨氯地平片有关物质%Determination of related substances of valsartan and amlodipine tablets by HPLC

    Institute of Scientific and Technical Information of China (English)

    彭熙琳; 吴品江; 周唯兰; 周芯宇; 李元波

    2014-01-01

    目的:建立一种高效液相色谱(HPLC)法测定缬沙坦氨氯地平片有关物质。方法用十八烷基硅烷键合硅胶为填充剂;以三乙胺溶液(用磷酸调 pH值至2.8)-甲醇-乙腈作为流动相,梯度洗脱,流速1.0 mL/min,柱温40℃,检测波长238 nm,进样量10μL。结果其降解产物与主峰在该色谱条件下能够有效分离。结论该方法简便、准确,系统适用性好,可作为缬沙坦氨氯地平片有关物质的检验方法。%Objective To establish a HPLC method for determining the related substances of valsartan and amlodipine tablets. Methods With octadecylsilane chemically bonded silica as the filler,the mixture of triethylamine(adjusting pH to 2.8 with phos-phoric acid)-methanol-acetonitrile was acted as the mobile phase by the gradient elution.The flow rate:1 .0 mL/min.The tempera-ture:40 ℃.The detection wavelength:238 nm.The injection volume:10μL.Results With octadecylsilane chemically bonded sili-ca as the filler,the mixture of triethylamine(adjusting pH to 2.8 with phosphoric acid)-methanol-acetonitrile was acted as the mo-bile phase by the gradient elution.The flow rate:1.0 mL/min.The temperature:40 ℃.The detection wavelength:238 nm.The injection volume:10μL.Conclusion This method is simple and accurate with good system suitability and can be used as the test method for the related substances of valsartan and amlodipine tablets.

  1. Acidic Microclimate pH Distribution in PLGA Microspheres Monitored by Confocal Laser Scanning Microscopy

    OpenAIRE

    Ding, Amy G.; Schwendeman, Steven P.

    2008-01-01

    The microclimate pH (μpH) distribution inside poly(lactic-co-glycolic acid) (PLGA) microspheres was monitored quantitatively over an acidic range as a function of several formulation variables. A ratiometric method by confocal laser scanning microscopy with Lysosensor yellow/blue® dextran was adapted from those previously reported, and μpH distribution kinetics inside PLGA microspheres was examined during incubation under physiologic conditions for 4 weeks. The effects of polymer molecular we...

  2. Role of pH on antioxidants production by Spirulina (Arthrospira) platensis

    OpenAIRE

    Mostafa Mahmoud Sami Ismaiel; Yassin Mahmoud El-Ayouty; Michele Piercey-Normore

    2016-01-01

    Abstract Algae can tolerate a broad range of growing conditions but extreme conditions may lead to the generation of highly dangerous reactive oxygen species (ROS), which may cause the deterioration of cell metabolism and damage cellular components. The antioxidants produced by algae alleviate the harmful effects of ROS. While the enhancement of antioxidant production in blue green algae under stress has been reported, the antioxidant response to changes in pH levels requires further investig...

  3. Coralline algal physiology is more adversely affected by elevated temperature than reduced pH

    OpenAIRE

    Román Manuel Vásquez-Elizondo; Susana Enríquez

    2016-01-01

    In this study we analyzed the physiological responses of coralline algae to ocean acidification (OA) and global warming, by exposing algal thalli of three species with contrasting photobiology and growth-form to reduced pH and elevated temperature. The analysis aimed to discern between direct and combined effects, while elucidating the role of light and photosynthesis inhibition in this response. We demonstrate the high sensitivity of coralline algae to photodamage under elevated temperature ...

  4. Contributions of functional groups and extracellular polymeric substances on the biosorption of dyes by aerobic granules.

    Science.gov (United States)

    Gao, Jing-Feng; Zhang, Qian; Wang, Jin-Hui; Wu, Xue-Lei; Wang, Shu-Ying; Peng, Yong-Zhen

    2011-01-01

    The contributions of loosely bound extracellular polymeric substances (LB-EPS), tightly bound EPS (TB-EPS), residual sludge (the sludge left after EPS extraction) and functional groups such as amine, carboxyl, phosphate and lipid on aerobic granules on biosorption of four different dyes (Reactive Brilliant Blue KN-R (KN-R), Congo Red (CR), Reactive Brilliant Red K-2G (RBR) and Malachite Green (MG)) were investigated. EPS may be responsible for biosorption of cationic dyes. However, residual sludge always made greater contribution than that of EPS. The biosorption mechanisms were dependent on the functional groups on aerobic granules and dyes' chemical structures. The lipid and phosphate groups might be the main binding sites for KN-R biosorption. Amine, carboxyl, phosphate and lipid were all responsible for the binding of CR. The lipid fractions played an important role for RBR biosorption. For MG, the phosphate groups gave the largest contribution. PMID:20869236

  5. Specific determination of clinical and toxicological important substances in biological samples by LC-MS

    International Nuclear Information System (INIS)

    This thesis of this dissertation is the specific determination of clinical and toxicological important substances in biological samples by LC-MS. Nicotine was determined in serum after application of nicotine plaster and nicotine nasal spray with HPLC-ESI-MS. Cotinine was determined direct in urine with HPLC-ESI-MS. Short time anesthetics were determined in blood and cytostatics were determined in liquor with HPLC-ESI-MS. (botek)

  6. Quantification, qualification, and microbial killing efficiencies of antimicrobial chlorine-based substances produced by iontophoresis.

    OpenAIRE

    Davis, C P; Shirtliff, M.E.; Trieff, N. M.; Hoskins, S L; Warren, M M

    1994-01-01

    The dependence of microbial killing on chloride ions present in solutions undergoing iontophoresis is addressed. A 400-microA current was applied to vials containing synthetic urine or saline, and the production of chlorine-based substances (CBSs) was detected by the N,N-diethyl-p-phenylene diamine colorimetric method. It was found that as the time of current application increased, the total concentration of CBSs also increased. The iontophoretic current converted (through oxidation) chloride...

  7. REGULATION OF PRODUCTION PERFORMANCE OF CHICORY PLANTS BY FOLIAR APPLICATION OF BIOLOGICALLY ACTIVE SUBSTANCES

    OpenAIRE

    MAREK KOVÁR; IVAN ČERNÝ

    2012-01-01

    In this study were evaluated both the growth and yield potentials of three chicory (Cichorium intybus var. sativum) varieties ('Fredonia Nova', 'Oesia' a 'Maurane') growing in natural agro-ecological conditions from 2006 to 2008. Regulation of the crop productivity by foliar application of biologically active substances (Atonik, Polybor 150, and Biafit Gold) was also studied. Evaluation of growth-production performance of chicory was realized as: leaf area index (LAI), photosynthetic potentia...

  8. Effects of Experimental Conditions on Extraction Yield of Extracellular Polymeric Substances by Cation Exchange Resin

    OpenAIRE

    Jinwoo Cho; Hermanowicz, Slawomir W; Jin Hur

    2012-01-01

    Effects of experimental conditions on the yield of extracellular polymeric substances (EPSs) extraction by cation exchange resin (CER) were investigated using activated sludge flocs. The experimental variables included resin dose, extraction time, sample dilution, and storage time. An empirical model was proposed to describe the kinetics of extraction process. The extraction yield increases with the extraction time and CER dose until it reached the maximum amount of EPS extraction. The maximu...

  9. Are psychotic experiences among detained juvenile offenders explained by trauma and substance use?

    OpenAIRE

    Colins, Olivier; Vermeiren, Robert; Vreugdenhil, Coby; Schuyten, Gilberte; Broekaert, Eric; Krabbendam, Anne

    2009-01-01

    Objective: High rates of psychotic experiences among detained adolescents have been reported. However, the significance of psychotic experiences in detained juveniles is still poorly understood. The current study, therefore, (1) examines whether psychotic experiences could be explained by substance use and/or traumatic experiences, and (2) investigates this objective without taking into account the frequently occurring paranoia-related symptoms that may not be psychosis-related in detained mi...

  10. Contingency Management for Attendance to Group Substance Abuse Treatment Administered by Clinicians in Community Clinics

    OpenAIRE

    Ledgerwood, David M.; Alessi, Sheila M.; Hanson, Tressa; Godley, Mark D.; Petry, Nancy M.

    2008-01-01

    Contingency management (CM) is effective in enhancing retention in therapy. After an 8-week baseline, four community-based substance abuse treatment clinics were exposed in random order to 16 weeks of standard care with CM followed by 16 weeks of standard care without CM or vice versa. In total, 75 outpatients participated. Patients who were enrolled in the clinics when the CM treatment phase was in effect attended a significantly greater percentage of therapy sessions than patients who were ...

  11. Production of bacteriocin-like substances by lactic acid bacteria isolated from regional ovine cheese

    OpenAIRE

    Cássia Regina Nespolo; Adriano Brandelli

    2010-01-01

    Lactic acid bacteria (LAB) were isolated from ovine milk and cheeses manufactured in the South Region of Brazil. Among 112 bacterial isolates investigated, 59 were chosen through a screening for LAB. Among these 59 strains of LAB, 21% showed antimicrobial, proteolytic and lipolytic activities. Based on this screening, Lactobacillus plantarum LCN 17 and Lactobacillus rhamnosus LCN 43 were selected and tested for the production of bacteriocin-like substances (BLS). The BLS produced by both isol...

  12. Cytotoxicity, calcium release, and pH changes generated by novel calcium phosphate cement formulations.

    Science.gov (United States)

    Khashaba, Rania M; Lockwood, Petra E; Lewis, Jill B; Messer, Regina L; Chutkan, Norman B; Borke, James L

    2010-05-01

    Few published studies describe the biological properties of calcium phosphate cements (CPCs) for dental applications. We measured several biologically relevant properties of 3 CPCs over an extended (8 wk) interval. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light-activated modified polyalkenoic acid, or 35% w/w polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs, respectively. Set cements were placed in direct contact with L929 fibroblasts for up to 8 weeks. Media Ca(+2) and pH were determined by atomic absorption spectroscopy and pH electrode respectively. Cell mitochondrial function was measured by MTT assay. Type I cements suppressed mitochondrial activity > 90% (vs. Teflon controls), but significantly (p 90% at all times. Type III cements elevated mitochondrial activity significantly after 7 wks. The pH profiles approached neutrality by 24 h, and all cements released calcium into the storage medium at all periods (24 h - 8 wk). We concluded that several types of cements had long-term biological profiles that show promise for dental applications. PMID:20235188

  13. Blood perfusion and pH monitoring in organs by laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Vari, Sandor G.; Papazoglou, Theodore G.; Pergadia, Vani R.; Stavridi, Marigo; Snyder, Wendy J.; Papaioannou, Thanassis; Duffy, J. T.; Weiss, Andrew B.; Thomas, Reem; Grundfest, Warren S.

    1994-01-01

    Sensitivity of laser-induced fluorescence spectroscopy (LIFS) in detecting a change in tissue pH, and blood perfusion was determined. Rabbits were anesthetized, paralyzed, and mechanically ventilated. The arterial and venous blood supplies of the kidney were isolated and ligated to alter the perfusion. The femoral artery was cannulated to extract samples for blood gas analysis. A 308-nm XeCl was used as an excitation source. A 600 micrometers core diameter fiber was used for fluorescence acquisition, and the spectra analyzed by an optical multichannel analyzer (EG & G, OMA III). the corresponding intensity ratio R equals INADH / ICOLL was used as an index for respiratory acidosis. Blood perfusion was assessed using the following algorithm: (IELAS minus ICOLL) divided by (INADH minus ICOLL). The intensity ratio linearly decreased with the reduction of blood perfusion. When we totally occluded the artery the ratio decreased tenfold when compared to the ratio of a fully perfused kidney. Results of monitoring blood acidosis by laser-induced fluorescence spectroscopy shows a significant trend between pH and intensity ratio. Since all the slopes were negative, there is an obvious significant correlation between the pH and NADH.COLLAGEN RATIO. Blue-light-induced fluorescence measurements and ratio fluorometry is a sensitive method for monitoring blood perfusion and acidity or alkalinity of an organ.

  14. Improved Low pH Emulsification Properties of Glycated Peanut Protein Isolate by Ultrasound Maillard Reaction.

    Science.gov (United States)

    Chen, Lin; Chen, Jianshe; Wu, Kegang; Yu, Lin

    2016-07-13

    In this work, peanut protein isolate (PPI) was grafted with maltodextrin (MD) through the ultrasound-assisted Maillard reaction. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed a link between PPI and MD. The substantially increased accessibility of the major subunits (conarachin, acidic subunit of arachin, and basic subunit of arachin) in PPI under high-intensity ultrasound treatment led to changes in the degree of graft (DG), zeta-potential, protein solubility, and surface hydrophobicity of conjugates. Emulsion systems (20% v/v oil, 2.0% w/v PPI equivalent, pH 3.8) formed by untreated PPI, PPI-MDC (PPI-MD conjugates obtained with wet-heating alone), and UPPI-MDC (PPI-MD conjugates obtained with ultrasound-assisted wet heating) were characterized using a light-scatter particle size analyzer and confocal laser scanning microscope. Results showed that emulsions of untreated PPI and PPI-MDC were not stable due to immediate bridging flocculation and coalescence of droplets, whereas that formed by UPPI-MDC with 32.4% DG was stable with a smaller mean droplet size. It was believed that high-intensity ultrasound promoted production of glycated PPI, which was soluble and surface active at pH 3.8 and thus improved emulsification properties for UPPI-MDC. This study shows that glycated PPI by ultrasound-assisted Maillard reaction is an effective emulsifying agent for low pH applications. PMID:27329355

  15. Determination of the Ph &Turbidity Value in Betul Block Five Year

    Directory of Open Access Journals (Sweden)

    Ravi Kumar

    2016-07-01

    Full Text Available Acidic and basic are two extremes that describe chemicals, just like hot and cold are two extremes that describe temperature. Mixing acids and bases can cancel out their extreme effects; much like mixing hot and cold water can even out the water temperature. A substance that is neither acidic nor basic is neutral. The ph of the water in betul block is increasing year by year and day by day. It was observed that there are 0.5% increase in the ph of water in betul block. The optimum pH will vary in different supplies according to the composition of the water and the nature of the construction materials used in the distribution system, but is often in the range 6.5–9.5. Extreme pH values can result from accidental spills, treatment breakdowns, and insufficiently cured cement mortar pipe linings. No health-based guideline value is proposed for pH.

  16. Red pigment production by Penicillium purpurogenum GH2 is influenced by pH and temperature

    Institute of Scientific and Technical Information of China (English)

    Alejandro MéNDEZ; Catalina PéREZ; Julio Cesar MONTEZ; Gabriela MARTíNEZ; Cristóbal Noé AGUILAR

    2011-01-01

    The combined effects of pH and temperature on red pigment production and fungal morphology were evaluated in a submerged culture of Penicillium purpurogenum GH2,using Czapek-Dox media with D-xylose as a carbon source.An experimental design with a factorial fix was used: three pH values (5,7,and 9) and two temperature levels (24 and 34 ℃) were evaluated.The highest production of red pigment (2.46 g/L) was reached with a pH value of 5 and a temperature of 24 ℃.Biomass and red pigment production were not directly associated.This study demonstrates that P.purpurogenum GH2 produces a pigment of potential interest to the food industry.It also shows the feasibility of producing and obtaining natural water-soluble pigments for potential use in food industries.A strong combined effect ((p)<0.05) of pH and temperature was associated with maximal red pigment production (2.46 g/L).

  17. PRELIMINARY DETECTION OF BACTERIOCIN-LIKE INHIBITORY SUBSTANCES PRODUCED BY ENTEROCOCCUS SPECIESISOLATED FROM DIFFERENT SOURCES

    Directory of Open Access Journals (Sweden)

    Snehal P Nemade and M Musaddiq

    2012-06-01

    Full Text Available Some lactic acid bacteria and particularly species belonging to the genus Enetrococcus are known to produce bacteriocin like inhibitory substance (BLIS. Usually they are small cationic peptide with bactericidal activity. The antimicrobial peptide produced by bacteria that deserve considerable interest for their use as natural and non-toxic food preservatives. The use of bacteriocin is among the new approaches as it has major potential in preservatives. Broad spectrum activities against prominent pathogens make it an issue of medical interest. The ability to produce such a biocompound may play role in providing an ecological advantage on non-bacteriocin producer species. 34 strains of Enterococci were isolated from different sources. These strains were identified to species: E. faecalis and E. faecium. Direct antimicrobial activity against indicator strain S. aureus was detected in 34 of the tested isolates. From these, only 7 displayed strong inhibitory activity against this indicator strain. The antimicrobial activity was altered after treatment with trypsin, α-chymotrypsin, papain which confirms the proteinaceous nature of the inhibition. This fact suggests that bacteriocin-like substance produced by Enterococcus strains may find application as biopreservatives in food products. Hence, the focus here is put on bacteriocin like substance screened by Enterococcus species isolated from different sources

  18. Biodegradation of trace pharmaceutical substances in wastewater by a membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    Longli BO; Taro URASE; Xiaochang WANG

    2009-01-01

    The biodegradation of selected pharmaceutical micropollutants, including two pharmaceuticals with argued biodegradation, was studied by a lab-scale membrane bioreactor. The reaction kinetics and affecting factors were also investigated in this paper. Clofibric acid (CA) with contradictive biodegradation reported was degraded almost completely at different hydraulic retention times (HRTs) after adaptation to microorganisms. The biodegradation of CA was disturbed at low pH operation,while the activity of microorganisms recovered again after pH adjustment to neutral condition. Ibuprofen (IBP)degraded under neutral and acidic conditions. Removals of IBP and CA were zero-order and first-order reactions under high and low initial concentrations, respectively. Carbamazepine and diclofenac were not degraded regardless of HRTs and pH.

  19. Effects of pH and ionic strength on precipitation of phytopathogenic viruses by polyethylene glycol.

    Science.gov (United States)

    Pastorek, J; Marcinka, K

    1989-01-01

    The effects of ionic strength of the solution (changed by varying NaCl concentrations or buffer molarity) on the precipitation with polyethylene glycol (PEG) 6000 were studied on phytopathogenic viruses of different morphology: the isometric red clover mottle virus (RCMV), rod-shaped tobacco mosaic virus, flexuous potato virus X (PVX) and bacilliform alfalfa mosaic virus. With increasing NaCl concentration or buffer molarity up to a certain level (0.1 mol/l), the efficiency of PEG precipitation increased. This relationship did not apply to PVX. The effects of pH on PEG precipitation were studied on RCMV. The efficiency of precipitation increased with decreasing difference between pH of the solution and pI of the virus. PMID:2565676

  20. Determination of related substances in lisinopril and amlodipine tablets by HPLC

    Institute of Scientific and Technical Information of China (English)

    Dao-Rui Yu; Gui-Fang Yang; Wen-Li Xiao; Jun Wang; Qi-Bing Liu

    2016-01-01

    Objective:To establish an HPLC method for determining the related substances in lisinopril and amlodipine tablets.Methods:An Inertsil Thermo BDS HYPERSIL C18 (4.6 mmí250 mm, 5 μm) column was used with the Acetonitrile-water-phosphoric acid (10:90:0.1) as mobile phase A and Acetonitrile-water-phosphoric acid (90:10:0.1) as mobile phase B by gradient elution at the detection wavelength of 215 nm. The flow rate was 1.0 mL/min and the column temperature was 30℃.Results: The separation of the impurity peak and peak was good. Besides, all the impurities could be detected effectively.Conclusions:The method is sensitive, accurate and selective. It is suitable for control the related substances in lisinopril and Amlodipine tablets.

  1. Novel emulsions stabilized by pH and temperature sensitive microgels

    Science.gov (United States)

    Ngai, To; Auweter, Helmut; Behrens, Sven

    2006-03-01

    Poly(N-isopropylacrylamide-co-methacrylic acid) (PNIPAM-MAA) microgel particles in aqueous solution exhibit a volume phase transition that can be induced by changes of either pH or temperature. In the swollen state, these microgels self-assemble at an octanol-water interface and can be used to stabilize surfactant-free oil-in-water emulsions. This stabilizing efficiency is retained even in the collapsed state, provided that the microgels are fully charged. At very low charge (low pH), on the other hand, the microgels migrate completely into the oil phase, and the emulsion breaks. In an intermediate regime of practical interest the emulsion stability can be tuned by small adjustments of pH or temperature. Because of this unprecedented stability control, we believe that such stimulus-responsive charged microgels have a great potential for applications in the field of cosmetic or pharmaceutical formulations. Conceptually they belong to a new class of emulsifiers combining properties of both classical surfactants and solid particles.

  2. Modeling the effect of pH on biosorption of heavy metals by citrus peels

    Energy Technology Data Exchange (ETDEWEB)

    Schiewer, Silke [Department of Civil and Environmental Engineering, University of Alaska Fairbanks, PO Box 755900, Fairbanks, AK 99775 (United States)], E-mail: ffsos@uaf.edu; Patil, Santosh B. [Department of Civil and Environmental Engineering, University of Alaska Fairbanks, PO Box 755900, Fairbanks, AK 99775 (United States)

    2008-08-30

    Biosorption by materials such as citrus peels could be a cost effective technique for removing toxic heavy metals from wastewater. Orange peels, lemon peels and lemon-based protonated pectin peels (PPP) had Langmuir sorption capacities of 0.7-1.2 mequiv./g (39-67 mg/g) of Cd per biosorbent dry weight. A potentiometric titration was interpreted using a continuous pK{sub a} spectrum approach. It revealed four acidic sites with pK{sub a} values of 3.8, 6.4, 8.4 and 10.7, and a total site quantity of 1.14 mequiv./g. Sorption isotherms of untreated citrus peels showed an unusual shape with two plateau values. Protonated pectin peels on the other hand showed a typical Langmuir behavior with a higher sorption capacity than untreated peels. At lower pH, metal binding was reduced due to increased competition by protons. This was modeled using pH-sensitive isotherm equations. It was not necessary to assume four binding sites; using one site with pK{sub a} 3.8 and a quantity of 1.14 mequiv./g was sufficient. It was possible to accurately predict metal uptake at one pH using the metal binding constant determined at a different pH. A 1:1 stoichiometry model fit the sorption isotherms shape better than a 1:2 stoichiometry. For constant pH, the 1:1 stoichiometry reduces to the Langmuir model.

  3. Urinary reducing substances in neonatal intrahepatic cholestasis caused by citrin deficiency

    Directory of Open Access Journals (Sweden)

    Ajmal Kader

    2014-06-01

    Full Text Available Neonatal cholestasis due to citrin deficiency is an autosomal recessive metabolic disorder caused by mutations in SLC25A13 gene. Mutations in this gene have a relatively high prevalence in East-Asian races compared to European or Afro-Caribbean races. Mutations in both sets of chromosomes often lead to self-limiting early onset cholestasis and growth retardation referred as neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD. It is associated with a wide range of metabolic derangements including galactosemia and aminoacidemia, which can be detected on the newborn blood spot screening. Galactose, being a reducing sugar, can also be detected using Clinitest® (Clinitest® Reagent Tablets, Bayer Corporation, Diagnostics Division, Elkhart, IN, USA, a common screening test used in the work up of metabolic and hepatic diseases. In the western population classical galactosemia is often suspected when non glucose reducing substances are detected in the urine of infants with cholestasis. However in East-Asian races the prevalence of classical galactosemia is very low whilst galactosemia due to altered uridine diphosphate-galactose epimerase activity in NICCD is more common. We present a case of NICCD in an East-Asian infant with cholestasis and persistently positive urine reducing substance. Conclusion: NICCD deficiency should be considered as a differential diagnosis in any infant with cholestasis and persistently positive urinary reducing substances.

  4. Metrological challenges for measurements of key climatological observables. Part 3: seawater pH

    Science.gov (United States)

    Dickson, A. G.; Camões, M. F.; Spitzer, P.; Fisicaro, P.; Stoica, D.; Pawlowicz, R.; Feistel, R.

    2016-02-01

    Water dissolves many substances with which it comes into contact, leading to a variety of aqueous solutions ranging from simple and dilute to complex and highly concentrated. Of the multiple chemical species present in these solutions, the hydrogen ion, H+, stands out in importance due to its relevance to a variety of chemical reactions and equilibria that take place in aquatic systems. This importance, and the fact that its presence can be assessed by reliable and inexpensive procedures, are the reasons why pH is perhaps the most measured chemical parameter. In this paper, while examining climatologically relevant ocean pH, we note fundamental problems in the definition of this key observable, and its lack of secure foundation on the International System of Units, the SI. The metrological history of seawater pH is reviewed, difficulties arising from its current definition and measurement practices are analysed, and options for future improvements are discussed in conjunction with the recent TEOS-10 seawater standard. It is concluded that the International Bureau of Weights and Measures (BIPM), in cooperation with the International Association for the Properties of Water and Steam (IAPWS), along with other international organisations and institutions, can make significant contributions by developing and recommending state-of-the-art solutions for these long standing metrological problems.

  5. The effect of chemical treatments on the pH & microbial flora of cassava residues during storage

    OpenAIRE

    Thaísa Anders Carvalho Souza; Manoel Soares Júnior; Maria Raquel Hidalgo Campos; Thaynara Stella Carvalho Souza; Lívia Cunha Bandeira

    2013-01-01

    Cassava starch factories produce residues that can be commercialized as food ingredients. The objective of this study was to evaluate the microbiological safety of cassava peel and bagasse during storage, with and without chemical treatment. The bagasse was acidified with lactic acid, and the peel was immersed in a sodium hypochlorite solution. The microbiological analyses were carried out for 72 h after harvest. All of the samples showed the absence of pathogenic microorganisms, and the acid...

  6. Evaluation of electrical conductivity, pH and refractive index as physico-chemical parameters for quality control of Aveloz homeopathic solutions

    Directory of Open Access Journals (Sweden)

    Sheila Garcia

    2011-09-01

    Full Text Available Euphorbia tirucalli Lineu (Aveloz belongs to the family Euphorbiaceae and is used in the treatment of cancer and warts. Some studies have reported that phorbol esters are the active principles responsible for the antitumor activity of Aveloz. The production of these molecules occurs in greater quantity in May, during the morning. This study aimed to evaluate whether the physico-chemical parameters of Aveloz homeopathic aqueous solutions such as pH, electrical conductivity and refractive index change due to storage time. Such parameters were measured regularly for 180 days. All solutions were prepared according to the method of grinding with lactose and subsequent dissolution in aqueous medium, as described in the Brazilian Homeopathic Pharmacopoeia, using as starting point the Aveloz latex collected in May. Homeopathic aqueous solutions containing only lactose were also prepared and evaluated as a control group. The potencies that were analyzed for electrical conductivity, pH and refractive index were: 4cH, 7cH, 9cH, 12cH, 14cH, 15cH, 29cH, 30cH. As a result, we found out that there was only statistical difference (p=0.035 in electrical conductivity between the homeopathic solutions containing Aveloz and the homeopathic solutions without Aveloz, when 15cH potency was compared. We also observed that the electrical conductivity increased with the aging of the solutions but is not directly related to the pH or the refractive index of the solutions, indicating that the aging process may alter the electrical conductivity of the homeopathic medicines. The presence of gas inside the glass that stores these solutions may affect the electrical conductivity measurements. Finally, no statistically significant difference was observed (p> 0.05 in the pH and refractive index.

  7. Minimization of sucrose losses in sugar industry by pH and temperature optimization

    International Nuclear Information System (INIS)

    Invert sugar has several disadvantage properties that play an important role in many food applications. It has a high affinity for water and is the cause of making products retain moisture. Invert sugar also affects the carmelization process, producing a browning effect. In this study, the possibility of minimization of sucrose inversion during the industrial production of sugar cane was investigated by the variation of the important parameters, i.e. temperature and pH of sugar cane juice for each of samples. The amounts of sucrose and reducing sugar alerting during the sucrose inversion process were determined by the values of % Pol and % reducing sugar (% RS), respectively. Starting with the study of temperature and pH effects of the sucrose solution with the concentration of 16 Brix, used as a sample model, it was found that no change in amounts of reducing sugar and sucrose was observed at room temperature (34 degree Celsius) in the pH range of 5-11. At pH 3, the amounts of reducing sugar increased and the amount of sucrose decreased as the time increased. These indicated that the process of sucrose inversion should better occur in more acidic solutions. Compared to the room temperature, it was found that the increment of temperature led to enhance the process of sucrose inversion. This was depicted by higher values of % RS and lower value of % Pol as the temperatures were elevated. The experiments were also done with real sugar cane juice, i.e. first, last, and mixed juice. The tendency of changes of the amounts of reducing sugar and sucrose in sugar cane samples by varying temperature and pH were found to resemble to those for the sample model. The increment of temperatures have also affected on a reduction of amounts of sucrose in each sugar cane juice. In addition, it could be concluded that the acidity of the solution affects sucrose easier to be broken down to glucose and fructose molecules. (author)

  8. Coralline algal physiology is more adversely affected by elevated temperature than reduced pH.

    Science.gov (United States)

    Vásquez-Elizondo, Román Manuel; Enríquez, Susana

    2016-01-01

    In this study we analyzed the physiological responses of coralline algae to ocean acidification (OA) and global warming, by exposing algal thalli of three species with contrasting photobiology and growth-form to reduced pH and elevated temperature. The analysis aimed to discern between direct and combined effects, while elucidating the role of light and photosynthesis inhibition in this response. We demonstrate the high sensitivity of coralline algae to photodamage under elevated temperature and its severe consequences on thallus photosynthesis and calcification rates. Moderate levels of light-stress, however, were maintained under reduced pH, resulting in no impact on algal photosynthesis, although moderate adverse effects on calcification rates were still observed. Accordingly, our results support the conclusion that global warming is a stronger threat to algal performance than OA, in particular in highly illuminated habitats such as coral reefs. We provide in this study a quantitative physiological model for the estimation of the impact of thermal-stress on coralline carbonate production, useful to foresee the impact of global warming on coralline contribution to reef carbon budgets, reef cementation, coral recruitment and the maintenance of reef biodiversity. This model, however, cannot yet account for the moderate physiological impact of low pH on coralline calcification. PMID:26740396

  9. Measurement of pH and Eh in saline solutions for a better knowledge of the chemical environment in nuclear repositories

    International Nuclear Information System (INIS)

    The mobility of heavy metals and radionuclides in aqueous systems strongly depends on the 2 geochemical master variables Eh and pH. Their potentiometric measurement in highly concentrated solutions which are typical for salt formations is complicated by liquid junction potentials that alter the cell potentials in an unpredictable way. The difference between apparent pH and the negative logarithm of H+ concentration (ΔpH) may amount to several pH units in highly saline solutions. This distorts geochemical modeling results significantly. For Eh measurements a rather small deviation is observed. For the calculation of the Fe2+/Fe3+ activities, further Pitzer ion interaction parameters valid in highly saline systems have to be developed

  10. Target and suspect screening of psychoactive substances in sewage-based samples by UHPLC-QTOF.

    Science.gov (United States)

    Baz-Lomba, J A; Reid, Malcolm J; Thomas, Kevin V

    2016-03-31

    The quantification of illicit drug and pharmaceutical residues in sewage has been shown to be a valuable tool that complements existing approaches in monitoring the patterns and trends of drug use. The present work delineates the development of a novel analytical tool and dynamic workflow for the analysis of a wide range of substances in sewage-based samples. The validated method can simultaneously quantify 51 target psychoactive substances and pharmaceuticals in sewage-based samples using an off-line automated solid phase extraction (SPE-DEX) method, using Oasis HLB disks, followed by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF) in MS(e). Quantification and matrix effect corrections were overcome with the use of 25 isotopic labeled internal standards (ILIS). Recoveries were generally greater than 60% and the limits of quantification were in the low nanogram-per-liter range (0.4-187 ng L(-1)). The emergence of new psychoactive substances (NPS) on the drug scene poses a specific analytical challenge since their market is highly dynamic with new compounds continuously entering the market. Suspect screening using high-resolution mass spectrometry (HRMS) simultaneously allowed the unequivocal identification of NPS based on a mass accuracy criteria of 5 ppm (of the molecular ion and at least two fragments) and retention time (2.5% tolerance) using the UNIFI screening platform. Applying MS(e) data against a suspect screening database of over 1000 drugs and metabolites, this method becomes a broad and reliable tool to detect and confirm NPS occurrence. This was demonstrated through the HRMS analysis of three different sewage-based sample types; influent wastewater, passive sampler extracts and pooled urine samples resulting in the concurrent quantification of known psychoactive substances and the identification of NPS and pharmaceuticals. PMID:26965330

  11. Energy conversion technology by chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Oh, I.W.; Yoon, K.S.; Cho, B.W. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of)] [and others

    1996-12-01

    The sharp increase in energy usage according to the industry development has resulted in deficiency of energy resources and severe pollution problems. Therefore, development of the effective way of energy usage and energy resources of low pollution is needed. Development of the energy conversion technology by chemical processes is also indispensable, which will replace the pollutant-producing and inefficient mechanical energy conversion technologies. Energy conversion technology by chemical processes directly converts chemical energy to electrical one, or converts heat energy to chemical one followed by heat storage. The technology includes batteries, fuel cells, and energy storage system. The are still many problems on performance, safety, and manufacturing of the secondary battery which is highly demanded in electronics, communication, and computer industries. To overcome these problems, key components such as carbon electrode, metal oxide electrode, and solid polymer electrolyte are developed in this study, followed by the fabrication of the lithium secondary battery. Polymer electrolyte fuel cell, as an advanced power generating apparatus with high efficiency, no pollution, and no noise, has many applications such as zero-emission vehicles, on-site power plants, and military purposes. After fabricating the cell components and operating the single cells, the fundamental technologies in polymer electrolyte fuel cell are established in this study. Energy storage technology provides the safe and regular heat energy, irrespective of the change of the heat energy sources, adjusts time gap between consumption and supply, and upgrades and concentrates low grade heat energy. In this study, useful chemical reactions for efficient storage and transport are investigated and the chemical heat storage technology are developed. (author) 41 refs., 90 figs., 20 tabs.

  12. Dissolution and Mobilization of Uranium in a Reduced Sediment by Natural Humic Substances under Anaerobic Conditions

    International Nuclear Information System (INIS)

    Biological reduction and precipitation of uranium (U) has been proposed as a remedial option for immobilizing uranium at contaminated sites, but the long-term stability and mobility of uranium remain a concern because it is neither removed nor destroyed. In this study, the dissolution and mobilization of reduced and oxidized forms of uranium [U(IV) and U(VI)] by natural humic substances were investigated in batch and column flow systems using a bioreduced sediment containing both U(IV) and U(VI). The addition of humic substances significantly increased the dissolution of U(IV) under anaerobic conditions. Humic acid (HA) was found to be more effective than fulvic acid (FA) in dissolving U(IV) in either 1 mM KCl or KHCO3 background solution. However, more U(VI) was dissolved in 1 mM KHCO3 than in 1 mM KCl background electrolytes. The HA also was found to be more effective than FA in mobilizing uranium under reducing and column flow conditions, although an accumulative amount of eluted U(VI) and U(IV) was relatively low (<60 μg) after leaching with ∼97 pore volumes of the humic solution in 1 mM KHCO3. These observations suggest that natural humic substances could potentially influence the long-term stability of bioreduced U(IV) even under strong reducing environments.

  13. Characteristics of Soil Humic Substances as Determined by Conventional and Synchrotron Fourier Transform Infrared Spectroscopy

    Science.gov (United States)

    Wang, S.; Song, X. Y.; Wang, N.; Li, C. X.; Wang, W.; Zhang, J. J.

    2014-11-01

    Humic substances (HS) play an important role in soil fertility and carbon sequestration in soil. The structural characteristics of soil HS, extracted from two natural soils and a laboratory-incubated soil, were investigated by conventional beamline-based Fourier transform infrared radiation (CB-FTIR), a common FTIR technique based on a conventional thermal source, and synchrotron radiation-based (SR-FTIR) spectroscopy. The relative area of absorbance peaks that appeared at 2930, 2860, 1711, and 1635 cm-1 were calculated to make a comparison of the absorbance intensities. The absorption of aromatic functional groups of HS was stronger in SR-FTIR spectroscopy than in CB-FTIR spectroscopy. Compared with humic acid extracted with a 0.1 mol/l Na4P2O7 solution, the level of aliphaticity in humic acid extracted with a 0.1 mol/l NaOH solution was higher. The aliphaticity of humin associated with clay (HMc) was higher than that of humin associated with iron (HMi). These results suggest that SR-FTIR spectroscopy is a useful and nondestructive technique to study the structural characteristics of soil humic substances. Sequential extraction of soil humic substances with NaOH and Na4P2O7 solutions may be helpful in providing additional information in cases where differences in the material obtained from different extraction solutions occur. The aliphaticity and complexity of HMc were higher than those of HMi.

  14. Influence of the initial ph of sugar cane juice on the production of levan by Zymomonas mobilis ATCC 31821

    OpenAIRE

    Marcia Sadae Tano; João Batista Buzato

    2002-01-01

    The influence of initial pH of sugar cane juice in high concentration was investigated for levan production by Zymomonas mobilis. In the initial pH of medium of 5.4; 5.9 and 6..3 the levan concentration achieved 1.66; 2.54 and 3.83 g/L, respectively, in 48 hours of fermentation. The final levan concentration in the initial pH of 6.3 and 5.9 increased 130 and 53% when compared to concentration at initial pH 5.4 in the medium. The levan yield at pH 5.9 was 87.5% and at pH 6.3 was 162.5% superio...

  15. Chemical transport reactions

    CERN Document Server

    Schäfer, Harald

    2013-01-01

    Chemical Transport Reactions focuses on the processes and reactions involved in the transport of solid or liquid substances to form vapor phase reaction products. The publication first offers information on experimental and theoretical principles and the transport of solid substances and its special applications. Discussions focus on calculation of the transport effect of heterogeneous equilibria for a gas motion between equilibrium spaces; transport effect and the thermodynamic quantities of the transport reaction; separation and purification of substances by means of material transport; and

  16. Calcite crystal growth inhibition by humic substances with emphasis on hydrophobic acids from the Florida Everglades

    Science.gov (United States)

    Hoch, A.R.; Reddy, M.M.; Aiken, G.R.

    2000-01-01

    The crystallization of calcium carbonate minerals plays an integral role in the water chemistry of terrestrial ecosystems. Humic substances, which are ubiquitous in natural waters, have been shown to reduce or inhibit calcite crystal growth in experiments. The purpose of this study is to quantify and understand the kinetic effects of hydrophobic organic acids isolated from the Florida Everglades and a fulvic acid from Lake Fryxell, Antarctica, on the crystal growth of calcite (CaCO3). Highly reproducible calcite growth experiments were performed in a sealed reactor at constant pH, temperature, supersaturation (?? = 4.5), P(CO2) (10-3.5atm), and ionic strength (0.1 M) with various concentrations of organic acids. Higher plant-derived aquatic hydrophobic acids from the Everglades were more effective growth inhibitors than microbially derived fulvic acid from Lake Fryxell. Organic acid aromaticity correlated strongly with growth inhibition. Molecular weight and heteroatom content correlated well with growth inhibition, whereas carboxyl content and aliphatic nature did not. Copyright (C) 1999 Elsevier Science Ltd.

  17. Analyses of the Erosive Effect of Dietary Substances and Medications on Deciduous Teeth.

    Directory of Open Access Journals (Sweden)

    Adrian Lussi

    Full Text Available This study aimed at analysing the erosive potential of 30 substances (drinks, candies, and medicaments on deciduous enamel, and analyse the associated chemical factors with enamel dissolution. We analysed the initial pH, titratable acidity (TA to pH 5.5, calcium (Ca, inorganic phosphate (Pi, and fluoride (F concentration, and degree of saturation ((pK -pIHAP, (pK -pIFAP, and (pK-pICaF2 of all substances. Then, we randomly distributed 300 specimens of human deciduous enamel into 30 groups (n = 10 for each of the substances tested. We also prepared 20 specimens of permanent enamel for the sake of comparison between the two types of teeth, and we tested them in mineral water and Coca-Cola®. In all specimens, we measured surface hardness (VHN: Vickers hardness numbers and surface reflection intensity (SRI at baseline (SH baseline and SRI baseline, after a total of 2 min (SH2 min and after 4 min (SH4 min and SRI4 min erosive challenges (60 ml of substance for 6 enamel samples; 30°C, under constant agitation at 95 rpm. There was no significant difference in SH baseline between deciduous and permanent enamel. Comparing both teeth, we observed that after the first erosive challenge with Coca-Cola®, a significantly greater hardness loss was seen in deciduous (-90.2 ± 11.3 VHN than in permanent enamel (-44.3 ± 12.2 VHN; p = 0.007, but no differences between the two types of teeth were observed after two challenges (SH4 min. After both erosive challenges, all substances except for mineral water caused a significant loss in relative surface reflectivity intensity, and most substances caused a significant loss in surface hardness. Multiple regression analyses showed that pH, TA and Ca concentration play a significant role in initial erosion of deciduous enamel. We conclude that drinks, foodstuffs and medications commonly consumed by children can cause erosion of deciduous teeth and erosion is mainly associated with pH, titratable acidity and calcium

  18. Interactions of Zn(II) Ions with Humic Acids Isolated from Various Type of Soils. Effect of pH, Zn Concentrations and Humic Acids Chemical Properties

    Science.gov (United States)

    Boguta, Patrycja; Sokołowska, Zofia

    2016-01-01

    The main aim of this study was the analysis of the interaction between humic acids (HAs) from different soils and Zn(II) ions at wide concentration ranges and at two different pHs, 5 and 7, by using fluorescence and FTIR spectroscopy, as well as potentiometric measurements. The presence of a few areas of HAs structures responsible for Zn(II) complexing was revealed. Complexation at α-sites (low humified structures of low-molecular weight and aromatic polycondensation) and β-sites (weakly humified structures) was stronger at pH 7 than 5. This trend was not observed for γ-sites (structures with linearly-condensed aromatic rings, unsaturated bonds and large molecular weight). The amount of metal complexed at pH5 and 7 by α and γ-structures increased with a decrease in humification and aromaticity of HAs, contrary to β-areas where complexation increased with increasing content of carboxylic groups. The stability of complexes was higher at pH 7 and was the highest for γ-structures. At pH 5, stability decreased with C/N increase for α-areas and -COOH content increase for β-sites; stability increased with humification decrease for γ-structures. The stability of complexes at α and β-areas at pH 7 decreased with a drop in HAs humification. FTIR spectra at pH 5 revealed that the most-humified HAs tended to cause bidentate bridging coordination, while in the case of the least-humified HAs, Zn caused bidentate bridging coordination at low Zn additions and bidentate chelation at the highest Zn concentrations. Low Zn doses at pH 7 caused formation of unidentate complexes while higher Zn doses caused bidentate bridging. Such processes were noticed for HAs characterized by high oxidation degree and high oxygen functional group content; where these were low, HAs displayed bidentate bridging or even bidentate chelation. To summarize, the above studies have showed significant impact of Zn concentration, pH and some properties of HAs on complexation reactions of humic

  19. Neuronal pH regulation

    DEFF Research Database (Denmark)

    Vorstrup, S; Jensen, K E; Thomsen, C;

    1989-01-01

    The intracellular pH in the brain was studied in six healthy volunteers before and immediately after the administration of 2 g of acetazolamide. Phosphorus-31 nuclear magnetic resonance spectroscopy by a 1.5 tesla whole-body scanner was used. The chemical shift between the inorganic phosphate and...... the phosphocreatine resonance frequencies was used for indirect assessment of the intracellular pH. The mean baseline intracellular pH was 7.05 +/- 0.04 (SD). The mean pH changes obtained at 15-min intervals within the first hour of acetazolamide administration were -0.03 +/- 0.04 (SD), -0.02 +/- 0.......03 (SD), and 0.00 +/- 0.04 (SD), i.e., no statistically significant pH decrease was observed during the period where extracellular pH is known to drop markedly. Although several factors contribute to the lack of change of the intraneuronal pH, we will discuss that this observation in addition might...

  20. Determination of electroless deposition by chemical nickeling

    Directory of Open Access Journals (Sweden)

    M. Badida

    2013-07-01

    Full Text Available Increasing of technical level and reliability of machine products in compliance with the economical and ecological terms belongs to the main trends of the industrial development. During the utilisation of these products there arise their each other contacts and the interaction with the environment. That is the reason for their surface degradation by wear effect, corrosion and other influences. The chemical nickel-plating allows autocatalytic deposition of nickel from water solutions in the form of coherent, technically very profitable coating without usage of external source of electric current. The research was aimed at evaluating the surface changes after chemical nickel-plating at various changes of technological parameters.

  1. Chemical bond cleavage induced by electron heating

    International Nuclear Information System (INIS)

    Gas emissions from titanium-metalloid compounds (titanium nitride and oxide) have been investigated to understand the effects of a microwave field on chemical reactions. We employed a high vacuum system (PO2 = 10−6 Pa) to observe in situ reductions. For titanium oxides, H-field heating significantly differed from conventional one in terms of oxygen emissions. For titanium nitride, the emissions were also induced by microwave heating. These tendencies were observed at temperatures above 1000 °C. A quantum chemical interpretation is provided to explain the emissions of the gases, and the experimental data is in good agreement with results predicted using the electronic energy band structure.

  2. Impacts of variable pH on stability and nutrient removal efficiency of aerobic granular sludge.

    Science.gov (United States)

    Lashkarizadeh, Monireh; Munz, Giulio; Oleszkiewicz, Jan A

    2016-01-01

    The impact of pH variation on aerobic granular sludge stability and performance was investigated. A 9-day alkaline (pH=9) and acidic (pH=6) pH shocks were imposed on mature granules with simultaneous chemical oxygen demand (COD), nitrogen and phosphorus removal. The imposed alkaline pH shock (pH 9) reduced nitrogen and phosphorus removal efficiency from 88% and 98% to 66% and 50%, respectively, with no further recovery. However, acidic pH shock (pH 6) did not have a major impact on nutrient removal and the removal efficiencies recovered to their initial values after 3 days of operation under the new pH condition. Operating the reactors under alkaline pH induced granules breakage and resulted in an increased solids concentration in the effluent and a significant decrease in the size of the bio-particles, while acidic pH did not have significant impacts on granules stability. Changes in chemical structure and composition of extracellular polymeric substances (EPS) matrix were suggested as the main factors inducing granules instability under high pH. PMID:26744935

  3. Autonomous Chemical Vapour Detection by Micro UAV

    Directory of Open Access Journals (Sweden)

    Kent Rosser

    2015-12-01

    Full Text Available The ability to remotely detect and map chemical vapour clouds in open air environments is a topic of significant interest to both defence and civilian communities. In this study, we integrate a prototype miniature colorimetric chemical sensor developed for methyl salicylate (MeS, as a model chemical vapour, into a micro unmanned aerial vehicle (UAV, and perform flights through a raised MeS vapour cloud. Our results show that that the system is capable of detecting MeS vapours at low ppm concentration in real-time flight and rapidly sending this information to users by on-board telemetry. Further, the results also indicate that the sensor is capable of distinguishing “clean” air from “dirty”, multiple times per flight, allowing us to look towards autonomous cloud mapping and source localization applications. Further development will focus on a broader range of integrated sensors, increased autonomy of detection and improved engineering of the system.

  4. Six rapid assessments of alcohol and other substance use in populations displaced by conflict

    Directory of Open Access Journals (Sweden)

    Adelekan Moruf

    2011-02-01

    Full Text Available Abstract Background Substance use among populations displaced by conflict is a neglected area of public health. Alcohol, khat, benzodiazepine, opiate, and other substance use have been documented among a range of displaced populations, with wide-reaching health and social impacts. Changing agendas in humanitarian response-including increased prominence of mental health and chronic illness-have so far failed to be translated into meaningful interventions for substance use. Methods Studies were conducted from 2006 to 2008 in six different settings of protracted displacement, three in Africa (Kenya, Liberia, northern Uganda and three in Asia (Iran, Pakistan, and Thailand. We used intervention-oriented qualitative Rapid Assessment and Response methods, adapted from two decades of experience among non-displaced populations. The main sources of data were individual and group interviews conducted with a culturally representative (non-probabilistic sample of community members and service providers. Results Widespread use of alcohol, particularly artisanally-produced alcohol, in Kenya, Liberia, Uganda, and Thailand, and opiates in Iran and Pakistan was believed by participants to be linked to a range of health, social and protection problems, including illness, injury (intentional and unintentional, gender-based violence, risky behaviour for HIV and other sexually transmitted infection and blood-borne virus transmission, as well as detrimental effects to household economy. Displacement experiences, including dispossession, livelihood restriction, hopelessness and uncertain future may make communities particularly vulnerable to substance use and its impact, and changing social norms and networks (including the surrounding population may result in changed - and potentially more harmful-patterns of use. Limited access to services, including health services, and exclusion from relevant host population programmes, may exacerbate the harmful consequences

  5. Modulation of Intestinal Functions by Dietary Substances: An Effective Approach to Health Promotion

    OpenAIRE

    SHIMIZU, Makoto

    2012-01-01

    Food contains a variety of substances than can modulate transport,barrier, detoxification, and immune functions of the intestines. Functional foods with those substances will be beneficial in promoting gut health, and eventually prevent lifestyle-related diseases.

  6. Group Delphi Workshop on In Silico Methods : successful communication of scientific content on the example of testing chemical substances

    OpenAIRE

    Benighaus, Christina; Renn, Ortwin; Benighaus, Ludger; Hinderer, Nele; Alle, Katrin

    2012-01-01

    The REACH Regulation (Registration, Evaluation, Authorization and Restriction of Chemicals) contains the commitment to minimize the amount of animal testing necessary to achieve its aims. To do this, industry is providing justifications to waive animal tests in preference for in vitro or in silico methods. In silico methods rely on computer simulation or modeling and use results from existing tests to model the ways in which a chemical may be hazardous in the body and/or in the environment. T...

  7. Enhanced production of 2,3-butanediol from glycerol by forced pH fluctuations.

    OpenAIRE

    Petrov, Kaloyan; Petrova, Penka

    2010-01-01

    The glycerol fermentation by Klebsiella pneumoniae occurs by receiving more than five liquid products-organic acids, diols, and ethanol. Aiming to direct the glycerol conversion towards predominant production of 2,3-butanediol (2,3-BD), the main influencing parameters (the aeration and the pH) were investigated during fed-batch processes. The regime of intensive aeration (2.2 vvm air supply) was evaluated as most favorable for 2,3-BD synthesis and ensured the decrease of all other metabolites...

  8. Molecular Rearrangement of an Aza-Scorpiand Macrocycle Induced by pH: A Computational Study

    Directory of Open Access Journals (Sweden)

    Jesus Vicente De Julián-Ortiz

    2016-07-01

    Full Text Available Rearrangements and their control are a hot topic in supramolecular chemistry due to the possibilities that these phenomena open in the design of synthetic receptors and molecular machines. Macrocycle aza-scorpiands constitute an interesting system that can reorganize their spatial structure depending on pH variations or the presence of metal cations. In this study, the relative stabilities of these conformations were predicted computationally by semi-empirical and density functional theory approximations, and the reorganization from closed to open conformations was simulated by using the Monte Carlo multiple minimum method.

  9. Measuring plant cell wall extension (creep) induced by acidic pH and by alpha-expansin.

    Science.gov (United States)

    Durachko, Daniel M; Cosgrove, Daniel J

    2009-01-01

    Growing plant cell walls characteristically exhibit a property known as 'acid growth', by which we mean they are more extensible at low pH (extensometer measurements. To measure acid-induced extension, the walls are initially buffered at neutral pH, resulting in low activity of expansins that are components of the native cell walls. Upon buffer exchange to acidic pH, expansins are activated and the cell walls extend rapidly. We also demonstrate expansin activity in a reconstitution assay. For this part, we use a brief heat treatment to denature the native expansins in the cell wall samples. These inactivated cell walls do not extend even in acidic buffer, but addition of expansins to the cell walls rapidly restores their ability to extend. PMID:19279553

  10. The X-ray fluorescence method for elementary analysis of substances by means of accelerated ions

    International Nuclear Information System (INIS)

    The modern state of the elementary analysis of substances by their characteristic X radiation (CXR), excited by accelerated ions is considered. The dependence of the analysis sensitivity on the type of accelerated ions and on their energy is discussed. The sources of background radiation are considered, and their effect on the analysis sensitivity in various energy ranges of the CXR is discussed. Compared are analytical possibilities of the method of analysis during the CXR excitation by electron and γ-quanta beams. The technique is considered in brief and the fields of the practical application in medicine, biology, in the investigation of environmental contamination are considered

  11. Fabrication of Graphene by Cleaving Graphite Chemically

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shu-hua; ZHAO Xiao-ting; FAN Hou-gang; YANG Li-li; ZHANG Yong-jun; YANG Jing-hai

    2011-01-01

    Graphite was chemically cleaved to graphene by Billups Reaction,and the morphologies and microstructures of graphene were characterized by SEM,Raman and AFM.The results show that the graphite was first functionalized by l-iodododecane,which led to the cleavage of the graphene layer in the graphite.The second decoration cleaved the graphite further and graphene was obtained.The heights of the graphene layer were larger than 1 nm due to the organic decoration.

  12. Cadmium and Zn availability as affected by pH manipulation and its assessment by soil extraction, DGT and indicator plants

    International Nuclear Information System (INIS)

    Manipulation of soil pH by soil additives and / or rhizosphere processes may enhance the efficiency of metal phytoextraction. Here we report on the effect of nitric acid additions to four polluted soils on Cd and Zn concentrations in soil solution (Csoln) and 0.005 M Ca(NO3)2 extracts, and related changes in the diffusive fluxes and resupply of the metals as assessed by diffusive gradients in thin films (DGT). The responses of these chemical indicators of bioavailability were compared to metal uptake in two indicator plant species, common dandelion (Taraxacum officinale F.H. Wigg) and narrow leaf plantain (Plantago lanceolata L.) grown for 75 days in a pot experiment. Lowering soil pH increased Csoln, the 0.005 M Ca(NO3)2-soluble fractions and the DGT-measured Cd and Zn concentrations (CDGT) in the experimental soils. This was associated with enhanced uptake of Cd and Zn on soils acidified to pH 4.5 whereas plants did not survive at pH 3.5. Toxicity along with decreased kinetics of metal resupply (calculated by the 2D DIFS model) in the strong acidification treatment suggests that moderate acidification is more appropriate to enhance the phytoextraction process. Each of the chemical indicators of bioavailability predicted well (R2 > 0.70) the Cd and Zn concentrations in plantain shoots but due to metal toxicity not for dandelion. Concentration factors, i.e. the ratio between metal concentrations in shoots and in soil solution (CF) indicate that Cd and Zn uptake in plantain was not limited by diffusion which may explain that DGT did not perform better than Csoln. However, DGT is expected to predict plant uptake better in diffusion-limited conditions such as in the rhizosphere of metal-accumulating phytoextraction crops. - Highlights: ► The effect of soil acidification was assessed for four Zn and Cd polluted soils. ► For some soils moderate acidification could enhance the metal uptake efficiency. ► Chemical assessment of bioavailability using soil solution and

  13. Cadmium and Zn availability as affected by pH manipulation and its assessment by soil extraction, DGT and indicator plants

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Iqbal; Puschenreiter, Markus, E-mail: markus.puschenreiter@boku.ac.at; Wenzel, Walter W.

    2012-02-01

    Manipulation of soil pH by soil additives and / or rhizosphere processes may enhance the efficiency of metal phytoextraction. Here we report on the effect of nitric acid additions to four polluted soils on Cd and Zn concentrations in soil solution (C{sub soln}) and 0.005 M Ca(NO{sub 3}){sub 2} extracts, and related changes in the diffusive fluxes and resupply of the metals as assessed by diffusive gradients in thin films (DGT). The responses of these chemical indicators of bioavailability were compared to metal uptake in two indicator plant species, common dandelion (Taraxacum officinale F.H. Wigg) and narrow leaf plantain (Plantago lanceolata L.) grown for 75 days in a pot experiment. Lowering soil pH increased C{sub soln}, the 0.005 M Ca(NO{sub 3}){sub 2}-soluble fractions and the DGT-measured Cd and Zn concentrations (C{sub DGT}) in the experimental soils. This was associated with enhanced uptake of Cd and Zn on soils acidified to pH 4.5 whereas plants did not survive at pH 3.5. Toxicity along with decreased kinetics of metal resupply (calculated by the 2D DIFS model) in the strong acidification treatment suggests that moderate acidification is more appropriate to enhance the phytoextraction process. Each of the chemical indicators of bioavailability predicted well (R{sup 2} > 0.70) the Cd and Zn concentrations in plantain shoots but due to metal toxicity not for dandelion. Concentration factors, i.e. the ratio between metal concentrations in shoots and in soil solution (CF) indicate that Cd and Zn uptake in plantain was not limited by diffusion which may explain that DGT did not perform better than C{sub soln}. However, DGT is expected to predict plant uptake better in diffusion-limited conditions such as in the rhizosphere of metal-accumulating phytoextraction crops. - Highlights: Black-Right-Pointing-Pointer The effect of soil acidification was assessed for four Zn and Cd polluted soils. Black-Right-Pointing-Pointer For some soils moderate acidification could

  14. Cl- transport pathways regulated by Ca++, cAMP, and pH in human fibroblasts

    International Nuclear Information System (INIS)

    Under basal conditions Cl- efflux from human fibroblasts occurs with a rate constant of permeability of 0.08 min-1. 50% of the basal efflux is due to Cl-/anion exchange and is DIDS inhibitable, 25% is due to Na+/K+/Cl- cotransport and is furosemide inhibitable, and 20% is due to an electrically conductive pathway. Increasing intracellular Ca++ with A23187 stimulates Cl- efflux by 30%. This increase appears to occur entirely via an electrically conducting pathway, but unlike basal Cl- conductance, it is DIDS sensitive. Exposure of the cells to dibutyryl cAMP stimulates Cl- efflux by 15%. They do not yet know whether the cAMP stimulated pathway is electrically conductive, but the stimulation is additive with that caused by elevated Ca++ suggesting that different pathways are activated. Elevation of intracellular pH by any of several standard methods increases Cl- efflux by as much as 700%. The pH effect appears to be mediated by a Cl-/anion exchange pathway since it is DIDS sensitive and electroneutral. Previous work from this laboratory describing a transient rapid efflux of Cl- followed by a slower efflux phase can now be explained as the result of a transient alkalinization of cells rather than as 2 subcellular Cl- compartments. This alkalinization occurs when cells are transferred from a 5% CO2 atmosphere during 36Cl- load to ambient CO2 for efflux

  15. Reduction of mercury (II) by humic substances-influence of pH, salinity of aquatic system

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Vudamala, K.; Coulibaly, M.; Ramteke, D.; Chennuri, K.; Lean, D.

    purposely not bubbled with N2 to avoid any kind of physical forcing during Hg-DOC interactions. It is assumed that the diffusion of Hg0 in different humic acid solutions is constant and analysis of Hg0 in headspace represents Hg(II) reduction processes...) The chemistry of atmospheric mercury : a review. Atm Environ 33: 2067–2079 Mason RP, Fitzgerald WF(1991) Mercury speciation in open ocean waters. Water Air & Soil Poll 56:779–789. Mason RP, Fitzgerald WF, Morel FMM(1994) The biogeochemical cycling...

  16. TPC2 controls pigmentation by regulating melanosome pH and size.

    Science.gov (United States)

    Ambrosio, Andrea L; Boyle, Judith A; Aradi, Al E; Christian, Keith A; Di Pietro, Santiago M

    2016-05-17

    Melanin is responsible for pigmentation of skin and hair and is synthesized in a specialized organelle, the melanosome, in melanocytes. A genome-wide association study revealed that the two pore segment channel 2 (TPCN2) gene is strongly linked to pigmentation variations. TPCN2 encodes the two-pore channel 2 (TPC2) protein, a cation channel. Nevertheless, how TPC2 regulates pigmentation remains unknown. Here, we show that TPC2 is expressed in melanocytes and localizes to the melanosome-limiting membrane and, to a lesser extent, to endolysosomal compartments by confocal fluorescence and immunogold electron microscopy. Immunomagnetic isolation of TPC2-containing organelles confirmed its coresidence with melanosomal markers. TPCN2 knockout by means of clustered regularly interspaced short palindromic repeat/CRISPR-associated 9 gene editing elicited a dramatic increase in pigment content in MNT-1 melanocytic cells. This effect was rescued by transient expression of TPC2-GFP. Consistently, siRNA-mediated knockdown of TPC2 also caused a substantial increase in melanin content in both MNT-1 cells and primary human melanocytes. Using a newly developed genetically encoded pH sensor targeted to melanosomes, we determined that the melanosome lumen in TPC2-KO MNT-1 cells and primary melanocytes subjected to TPC2 knockdown is less acidic than in control cells. Fluorescence and electron microscopy analysis revealed that TPC2-KO MNT-1 cells have significantly larger melanosomes than control cells, but the number of organelles is unchanged. TPC2 likely regulates melanosomes pH and size by mediating Ca(2+) release from the organelle, which is decreased in TPC2-KO MNT-1 cells, as determined with the Ca(2+) sensor tyrosinase-GCaMP6. Thus, our data show that TPC2 regulates pigmentation through two fundamental determinants of melanosome function: pH and size. PMID:27140606

  17. Nanoscale chemical imaging by photoinduced force microscopy.

    Science.gov (United States)

    Nowak, Derek; Morrison, William; Wickramasinghe, H Kumar; Jahng, Junghoon; Potma, Eric; Wan, Lei; Ruiz, Ricardo; Albrecht, Thomas R; Schmidt, Kristin; Frommer, Jane; Sanders, Daniel P; Park, Sung

    2016-03-01

    Correlating spatial chemical information with the morphology of closely packed nanostructures remains a challenge for the scientific community. For example, supramolecular self-assembly, which provides a powerful and low-cost way to create nanoscale patterns and engineered nanostructures, is not easily interrogated in real space via existing nondestructive techniques based on optics or electrons. A novel scanning probe technique called infrared photoinduced force microscopy (IR PiFM) directly measures the photoinduced polarizability of the sample in the near field by detecting the time-integrated force between the tip and the sample. By imaging at multiple IR wavelengths corresponding to absorption peaks of different chemical species, PiFM has demonstrated the ability to spatially map nm-scale patterns of the individual chemical components of two different types of self-assembled block copolymer films. With chemical-specific nanometer-scale imaging, PiFM provides a powerful new analytical method for deepening our understanding of nanomaterials. PMID:27051870

  18. Chemical composition and physico-chemical properties of meat from capons as affected by breed and age

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, O.; Rodriguez, L.; Torres, A.; Cobos, A.

    2010-07-01

    The influence of the breed [Mos (Spanish indigenous breed), Sasso T-44 and X-44 (commercial strains)] and the age (5, 6, 7 and 8 months) of capons (castrated male cockerels) on some qualitative traits of breast and drumstick meat were studied. The chemical composition (dry matter, protein, lipid and ash contents), pH, water holding capacity, drip loss, cooking loss, colour and texture (compression test and shear force) were measured. In breast meat, the Mos capon showed lower water holding capacity, higher drip loss and was lighter than the other breeds. In drumstick meat, the Mos capon showed lower lipid content, lower water holding capacity and was lighter and less red than the other breeds. Chemical composition, pH, water holding capacity, drip loss, colour and texture of the meat were significantly influenced by the age of the capons. The meat of the youngest animals showed higher ash content, higher pH, lower water holding capacity, higher drip loss, higher lightness and lower shear test values, than that of the older ones. In conclusion, the capon meat quality is influenced by breed and age of the capons. (Author) 36 refs.

  19. Recent findings on the characterization of humic substances extracted from soils from widely differing climatic zones

    International Nuclear Information System (INIS)

    To obtain information on the effect of climate on the analytical characteristics and chemical structure of humic substances, humic and fulvic acids were extracted from soils formed under Arctic, cool temperate, subtropical and tropical climates. All humic materials were extracted, fractionated, purified and analysed by the same methods. These included elementary and functional group analyses, spectrophotometry in the ultra-violet, visible and i.r. regions, Electron Spin Resonance (ESR) spectrometry and chemical degradation with alkaline KMnO4 and alkaline CuO. The oxidation products were separated by solvent extraction and chromatographic methods, and identified by mass spectrometry and micro-i.r. spectrophotometry. The analytical, spectrophotometric and spectrometric data, and the information provided by chemical degradation, showed that humic substances formed under widely differing climatic conditions had essentially similar chemical structures and characteristics. Major humic 'building blocks' were in all instances complex phenolic and benzene-carboxylic structures. Most of the aliphatics were n-fatty acids which appeared to be esterified to phenolic OH groups. Recent physico-chemical studies done in our laboratory show that humic and fulvic acids behave like linear, flexible polyelectrolytes that are readily aggregated, most likely with the aid of H-bonding, at low pH but dispersed, because of increased dissociation of functional groups, at higher pH. Thus, it becomes apparent at this time that humic and fulvic acids are not single molecules but molecular associations of phenolic and benzene-carboxylic compounds ('buildings blocks') of microbiological, polyphenolic, lignin and condensed lignin origins. The 'building blocks' appear to be held together by weak linkages, mainly H-bonds. (author)

  20. Selective synthesis of clinoatacamite Cu2(OH)3Cl and tenorite CuO nanoparticles by pH control

    DEFF Research Database (Denmark)

    Engelbrekt, Christian; Malcho, Phillip; Andersen, Jonas;

    2014-01-01

    Copper nanomaterials play a role as catalysts in sustainable energy technology and sensor devices. We present a one-pot synthesis for the selective preparation of phase-pure clinoatacamite (Cu2(OH)3Cl) and cupric oxide (CuO) nanoparticles by controlling the pH of the solution. The effect of pH on...