JICST Factual DatabaseJICST Chemical Substance Safety Regulation Database

Science.gov (United States)

Abe, Atsushi; Sohma, Tohru

JICST Chemical Substance Safety Regulation Database is based on the Database of Safety Laws for Chemical Compounds constructed by Japan Chemical Industry Ecology-Toxicology & Information Center (JETOC) sponsored by the Sience and Technology Agency in 1987. JICST has modified JETOC database system, added data and started the online service through JOlS-F (JICST Online Information Service-Factual database) in January 1990. JICST database comprises eighty-three laws and fourteen hundred compounds. The authors outline the database, data items, files and search commands. An example of online session is presented.

Features of the Italian National Inventory of Chemical Substances.

Science.gov (United States)

Binetti, R; Marcello, I

1994-01-01

The Italian National Inventory of Chemical Substances (Inventario nazionale delle sostanze chimiche, INSC), a factual data bank on chemical toxicology produced by the Istituto Superiore di Sanità (ISS), consists of a computerized system on existing chemicals developed for routinary and emergency needs. Historical background, current status and future direction of INSC are discussed. The structure and the feature of INSC are briefly examined. Aspects of retrieval of information and the criteria for the inclusion of data and priority selection are also considered.

78 FR 48051 - Significant New Use Rules on Certain Chemical Substances

Science.gov (United States)

2013-08-07

.... Potentially affected entities may include: Manufacturers or processors of one or more subject chemical... chemical substance. The extent to which a use changes the type or form of exposure of human beings or the... the regulatory text section of this rule. This rule includes PMN substances, P-09-198 and P-09-199...

Upper parameters of toxicity (LDsub(50/30)) of some radioactive and chemical substances

International Nuclear Information System (INIS)

Rodionova, L.F.; Kupriyanova, V.M.; Zasedatelev, A.A.

1978-01-01

The toxicities of radioactive ( 90 Sr, 210 Po) and chemical (lead nitrate, mercuric chloride) substances were compared using equivalent procedures. Ninety six doses of toxic substances in various concentrations were tested on mice to which these substances were administered by intragastric intubation. The material was processed and analyzed by conventional methods used in toxicology. The upper limits of toxicity for the tested substances were determined from their LDsub(50/30) values by various methods of calculation

Effect of pH on the production of alkaline proteinase by alkalophilic Bacillus sp

International Nuclear Information System (INIS)

Kitada, Makio; Horikoshi, Koki

1976-01-01

The effect of the pH of the medium on the microbial growth and alkaline proteinase production, and on the uptake of various substances by alkalophilic Bacillus sp. No.8-1 were studied to investigate the physiological properties of alkalophilic bacteria. Both the microbial growth and alkaline proteinase production by replacement culture were maximum between pH 9 and 10. The alkaline proteinase production sources were also effective for the production. The uptake of various substances such as glucose, acetate, amino acids, and uracil, necessary for proteinase production by this strain, was maximum between pH 9 and 10. The uptake of α-aminoisobutyric acid, a nonmetabolizable amino acid analogue, was also maximum at pH 10. The pH-dependence of these substance was not due to their ionic forms being affected by extracellular pH. It was concluded from above results that good production of alkaline proteinase in alkaline media was due to the active uptake of various nutrients in this culture condition. (auth.)

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

Effect of pH on the properties of ZnS thin films grown by chemical bath deposition

International Nuclear Information System (INIS)

Ben Nasr, T.; Kamoun, N.; Kanzari, M.; Bennaceur, R.

2006-01-01

Zinc sulphide thin films have been deposited on glass substrates using the chemical bath deposition technique. The depositions were carried out in the pH range of 10 to 11.5. Structure of these films was characterized by X-ray diffraction and scanning electron microscopy. Optical properties were studied by spectrophotometric measurements. Influence of the increased pH value on structural and optical properties is described and discussed in terms of transmission improvement in the visible range. Transmission spectra indicate a high transmission coefficient (∼70%). The direct band gap energy is found to be about 3.67 eV for the films prepared at pH equal to 11.5

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.

Children and the unborn child, Exposure and susceptibility to chemical substances – an evaluation

DEFF Research Database (Denmark)

Nielsen, Elsa; Thorup, I.; Schnipper, Anette

Children are at risk of exposure to a lot of high-production-volume synthetic chemical substances which have been introduced into the market within the past 50 years; these chemical substances are used widely in consumer products and are dispersed in the environment. Children as well as the unbor...... knowledge about the biological susceptibility and exposure of chemical substances to children during the embryonic, foetal, and postnatal periods....

Quantification of iopamidol multi-site chemical exchange properties for ratiometric chemical exchange saturation transfer (CEST) imaging of pH

International Nuclear Information System (INIS)

Sun, Phillip Zhe; Longo, Dario Livio; Hu, Wei; Xiao, Gang; Wu, Renhua

2014-01-01

pH-sensitive chemical exchange saturation transfer (CEST) MRI holds great promise for in vivo applications. However, the CEST effect depends on not only exchange rate and hence pH, but also on the contrast agent concentration, which must be determined independently for pH quantification. Ratiometric CEST MRI normalizes the concentration effect by comparing CEST measurements of multiple labile protons to simplify pH determination. Iopamidol, a commonly used x-ray contrast agent, has been explored as a ratiometric CEST agent for imaging pH. However, iopamidol CEST properties have not been solved, determination of which is important for optimization and quantification of iopamidol pH imaging. Our study numerically solved iopamidol multi-site pH-dependent chemical exchange properties. We found that iopamidol CEST MRI is suitable for measuring pH between 6 and 7.5 despite that T 1 and T 2 measurements varied substantially with pH and concentration. The pH MRI precision decreased with pH and concentration. The standard deviation of pH determined from MRI was 0.2 and 0.4 pH unit for 40 and 20 mM iopamidol solution of pH 6, and it improved to be less than 0.1 unit for pH above 7. Moreover, we determined base-catalyzed chemical exchange for 2-hydrooxypropanamido (k sw = 1.2*10 pH−4.1 ) and amide (k sw = 1.2*10 pH−4.6 ) protons that are statistically different from each other (P < 0.01, ANCOVA), understanding of which should help guide in vivo translation of iopamidol pH imaging. (paper)

78 FR 64210 - Extension of Review Periods Under the Toxic Substances Control Act; Certain Chemicals and...

Science.gov (United States)

2013-10-28

... Under the Toxic Substances Control Act; Certain Chemicals and Microorganisms; Premanufacture... 325 and 324110), e.g., chemical manufacturing and petroleum refineries. The North American Industrial... Agency under section 5 of the Toxic Substances Control Act (TSCA), received by EPA on or before October 1...

Chemical degradation of 3H-labeled substance P in tris buffer solution

International Nuclear Information System (INIS)

Higa, T.; Desiderio, D.M.

1988-01-01

Substance P (SP) is an important neuropeptide that has been implicated in several physiological processes, and it is necessary to devise an analytical procedure to measure endogenous SP with a combination of high sensitivity and maximum molecular specificity. However, the unique chemical nature of SP (polarity, chemical stability, ease of oxidation, peptide bond lability) plays a significant role in its analysis, such as in receptor assays, immunoassays, chromatography, and mass spectrometry. In this study, we evaluated in polypropylene and glass assay tubes the effects on the recovery and stability of tritiated SP ([3H]SP) of several pertinent experimental parameters such as buffer, pH, multiple freeze-thaw cycles, and incubation temperature and time. Bovine serum albumin (BSA) effectively reduced the absorption of [3H]SP to polypropylene and glass tube surfaces. Following multiple (6X) freeze-thaw cycles of solutions in BSA-precoated tubes, the recovery of radioactive [3H]SP remained high (greater than 75%) after the last cycle, whereas recovery was minimal in uncoated or siliconized glass tubes. A high level of radioactivity recovery was maintained for 14 days of storage of [3H]SP in triethylamine formate (TEAF) solution in BSA-precoated tubes at 4 and -20 degrees C, but decreased at 37 degrees C to less than 80% in only 3 h. Following storage in Tris-HCl (pH 7.4) buffer, a combination of HPLC and mass spectrometric analyses revealed that a significant amount of peptide bond cleavage occurred to produce the two peptides ArgProLys (RPK) and ArgProLysProGlnGln (RPKPQQ), with only a small amount of remaining intact SP. That decomposition was not observed in triethylamine formate TEAF (pH 3.14) buffer solutions

Chemical incidents resulted in hazardous substances releases in the context of human health hazards

Directory of Open Access Journals (Sweden)

Anna Pałaszewska-Tkacz

2017-02-01

Full Text Available Objectives: The research purpose was to analyze data concerning chemical incidents in Poland collected in 1999–2009 in terms of health hazards. Material and Methods: The data was obtained, using multimodal information technology (IT system, from chemical incidents reports prepared by rescuers at the scene. The final analysis covered sudden events associated with uncontrolled release of hazardous chemical substances or mixtures, which may potentially lead to human exposure. Releases of unidentified substances where emergency services took action to protect human health or environment were also included. Results: The number of analyzed chemical incidents in 1999–2009 was 2930 with more than 200 different substances released. The substances were classified into 13 groups of substances and mixtures posing analogous risks. Most common releases were connected with non-flammable corrosive liquids, including: hydrochloric acid (199 cases, sulfuric(VI acid (131 cases, sodium and potassium hydroxides (69 cases, ammonia solution (52 cases and butyric acid (32 cases. The next group were gases hazardous only due to physico-chemical properties, including: extremely flammable propane-butane (249 cases and methane (79 cases. There was no statistically significant trend associated with the total number of incidents. Only with the number of incidents with flammable corrosive, toxic and/or harmful liquids, the regression analysis revealed a statistically significant downward trend. The number of victims reported was 1997, including 1092 children and 18 fatalities. Conclusions: The number of people injured, number of incidents and the high 9th place of Poland in terms of the number of Seveso establishments, and 4 times higher number of hazardous industrial establishments not covered by the Seveso Directive justify the need for systematic analysis of hazards and their proper identification. It is advisable enhance health risk assessment, both qualitative and

TSCA Chemical Data Reporting Fact Sheet: Chemical Substances which are the Subject of Certain TSCA Actions

Science.gov (United States)

This fact sheet provides guidance for people who may be subject to the Chemical Data Reporting (CDR) rule on how their requirements for reporting for 2016 may be affected when chemical substances are the subject of certain TSCA actions.

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

Science.gov (United States)

2013-05-09

.... Potentially affected entities may include: Manufacturers, importers, or processors of one or more subject... of manufacturing and processing of a chemical substance. The extent to which a use changes the type...). CFR citation assigned in the regulatory text section of this rule. This rule includes a PMN substance...

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

Science.gov (United States)

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

2011-11-10

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. 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 long-term trends for prominent substances and substances considered in need of research attention. The 119,636 journal articles found had 760,056 CAS number links during 2000-2009. The top-20 environmental chemicals consisted of metals, (chlorinated) biphenyls, polyaromatic hydrocarbons, benzene, and ethanol and contributed 12% toward the total number of links- Each of the top-20 substances was covered by 2,000-10,000 articles during the decade. The numbers for the 10-year period were similar to the total numbers of pre-2000 articles on the same chemicals. However, substances considered a high priority from a regulatory viewpoint, due to lack of documentation, showed very low 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. The persistence of some environmental chemicals in the scientific literature may be due to a 'Matthew' principle of maintaining prominence for the very reason of having been well researched. Such bias detracts from the societal needs for documentation on less well known environmental hazards, and it may also impact negatively on the potentials for innovation and discovery in research.

Aquatic Humic Substances: Relationship Between Origin and Complexing Capacity.

Science.gov (United States)

González-Guadarrama, María de Jesús; Armienta-Hernández, Ma Aurora; Rosa, André H

2018-05-01

Aiming to determine the relationship between source and complexing capacity, humic substances obtained from three sites (Sorocaba and Itapanhau Brasilian rivers, and Xochimilco Lake in Mexico) were studied. Copper, manganese, zinc and arsenic complexing capacity were determined for the three substances under various pH conditions. Results showed similar complexing capacity for the three elements depending on the chemistry of each one and on the physico-chemical conditions. Speciation diagrams showed that these conditions affect both, the humic substances, and the transition metals and arsenic.

Analysis of the utilization of existing test data for phase-in substance registration under the Act on the Registration and Evaluation, etc. of Chemical Substances.

Science.gov (United States)

Choi, Bong-In; Kwak, Yeong-Don; Jung, Yu-Mi; Ryu, Byung-Taek; Kim, Chang Gyun

2015-01-01

Approximately 2000 phase-in substances are subject to registration according to the Act on the Registration and Evaluation, etc. of Chemical Substances (KREACH), and the expected testing cost is 2.06 trillion Korean won assuming all the test data required for registration are acquired. The extent to which these enormous test costs can be reduced depends on the availability of existing data that can be used to meet the requirements of the K-REACH we examined the current availability of test data that can be used for chemical substance registration. We analyzed the possibility of utilizing the existing test data obtained from 16 reference databases for 369 of 518 kinds of phase-in substances subject to registration that were reported in last October 2014. The physical and chemical properties were available for 57.1% of substances, whereas data regarding human hazards and environmental hazards were available at considerably lower rates, 8.5% and 11.8%, respectively. Physical and chemical properties were available for a fairly high proportion, whereas human hazards and environmental hazards were reported for considerably fewer substances.

Variation of iron redox kinetics and its relation with molecular composition of standard humic substances at circumneutral pH

OpenAIRE

Lee, Ying Ping; Fujii, Manabu; Kikuchi, Tetsuro; Terao, Koumei; Yoshimura, Chihiro

2017-01-01

Oxidation and reduction kinetics of iron (Fe) and proportion of steady-state Fe(II) concentration relative to total dissolved Fe (steady-state Fe(II) fraction) were investigated in the presence of various types of standard humic substances (HS) with particular emphasis on the photochemical and thermal reduction of Fe(III) and oxidation of Fe(II) by dissolved oxygen (O2) and hydrogen peroxide (H2O2) at circumneutral pH (pH 7-8). Rates of Fe(III) reduction were spectrophotometrically determined...

Study of grape contamination at the time of harvest using stable chemical substances analyzed by activation

International Nuclear Information System (INIS)

Miribel, J.; Delmas, J.

1989-01-01

In the sixties the SERE, in conjunction with the French National Institute for Agricultural Research (INRA), conducted experiments on the contamination of wine produced from vines contaminated at the roots. The contamination must be carried out via the leaves and at different stages of growth so as to come as close as possible to the conditions of fall-out. An initial study of grape contamination at the time of the harvest was carried out using stable chemical substances which were analysed by activation. This technique makes it possible to use a large number of substances at the same time and is harmless for the environment. The results obtained appear to be satisfactory, and the method will be used next year for studies at other stages in the ripening of grapes [fr

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

Directory of Open Access Journals (Sweden)

Grandjean Philippe

2011-11-01

Full Text Available 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 searches to determine long-term trends for prominent substances and substances considered in need of research attention. Results The 119,636 journal articles found had 760,056 CAS number links during 2000-2009. The top-20 environmental chemicals consisted of metals, (chlorinated biphenyls, polyaromatic hydrocarbons, benzene, and ethanol and contributed 12% toward the total number of links- Each of the top-20 substances was covered by 2,000-10,000 articles during the decade. The numbers for the 10-year period were similar to the total numbers of pre-2000 articles on the same chemicals. However, substances considered a high priority from a regulatory viewpoint, due to lack of documentation, showed very low 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 may be due to a 'Matthew' principle of maintaining prominence for the very reason of having been well researched. Such bias detracts from the societal needs for documentation on less well known environmental hazards, and it may also impact negatively on the potentials for innovation and discovery in research.

Removal of chemical substances from the atmosphere by photocatalysis; Hikarishokubai ni yoru kiso kagaku busshitsu no jokyo

Energy Technology Data Exchange (ETDEWEB)

Takeuchi, K; Kutsuna, S [National Institute for Resources and Environment, Tsukuba (Japan)

1996-01-25

Suppression at a source is the principle of suppressing air pollution caused by vapor phase chemical substances. For the case of these substances with extremely low concentrations, discussions were given on decomposition by means of photocatalysts (that utilize solar light) to directly purify them in the atmospheric condition. Catalysis takes place in providing and receiving electrons, that is, oxidation and reduction of the electrons, under light irradiation by using photocatalysts in which light excites and causes internal electrons to migrate freely. Titanium oxide was found effective because it is high in catalytic activity, stable chemically, and harmless. Photodecomposition reaction of chlorinated organic compounds on TiO2 proceeds very fast except for fluorocarbons. In practical use, the catalyst must be fixed so that no catalyst powder will scatter around. Porous TiO2 sheets were, therefore, manufactured using fluorine resin as a binder. The sheets were used to have removed successfully NOx, SO2 and low-grade aldehyde with concentrations from 0.01 to 10 ppm (corresponding to gases discharged from a tunnel). Since the catalyst can function even under solar light, it can remove NOx during daytime, and can be regenerated by precipitation (passive environment purification). The catalyst was verified effective when used on roads in urban areas. 16 refs., 9 figs., 3 tabs.

Variation of iron redox kinetics and its relation with molecular composition of standard humic substances at circumneutral pH.

Directory of Open Access Journals (Sweden)

Ying Ping Lee

Full Text Available Oxidation and reduction kinetics of iron (Fe and proportion of steady-state Fe(II concentration relative to total dissolved Fe (steady-state Fe(II fraction were investigated in the presence of various types of standard humic substances (HS with particular emphasis on the photochemical and thermal reduction of Fe(III and oxidation of Fe(II by dissolved oxygen (O2 and hydrogen peroxide (H2O2 at circumneutral pH (pH 7-8. Rates of Fe(III reduction were spectrophotometrically determined by a ferrozine method under the simulated sunlight and dark conditions, whereas rates of Fe(II oxidation were examined in air-saturated solution using luminol chemiluminescence technique. The reduction and oxidation rate constants were determined to substantially vary depending on the type of HS. For example, the first-order rate constants varied by up to 10-fold for photochemical reduction and 7-fold for thermal reduction. The degree of variation in Fe(II oxidation was larger for the H2O2-mediated reaction compared to the O2-mediated reaction (e.g., 15- and 3-fold changes for the former and latter reactions, respectively, at pH 8. The steady-state Fe(II fraction under the simulated sunlight indicated that the Fe(II fraction varies by up to 12-fold. The correlation analysis indicated that variation of Fe(II oxidation is significantly associated with aliphatic content of HS, suggesting that Fe(II complexation by aliphatic components accelerates Fe(II oxidation. The reduction rate constant and steady-state Fe(II fractions in the presence of sunlight had relatively strong positive relations with free radical content of HS, possibly due to the reductive property of radical semiquinone in HS. Overall, the findings in this study indicated that the Fe reduction and oxidation kinetics and resultant Fe(II formation are substantially influenced by chemical properties of HS.

Variation of iron redox kinetics and its relation with molecular composition of standard humic substances at circumneutral pH.

Science.gov (United States)

Lee, Ying Ping; Fujii, Manabu; Kikuchi, Tetsuro; Terao, Koumei; Yoshimura, Chihiro

2017-01-01

Oxidation and reduction kinetics of iron (Fe) and proportion of steady-state Fe(II) concentration relative to total dissolved Fe (steady-state Fe(II) fraction) were investigated in the presence of various types of standard humic substances (HS) with particular emphasis on the photochemical and thermal reduction of Fe(III) and oxidation of Fe(II) by dissolved oxygen (O2) and hydrogen peroxide (H2O2) at circumneutral pH (pH 7-8). Rates of Fe(III) reduction were spectrophotometrically determined by a ferrozine method under the simulated sunlight and dark conditions, whereas rates of Fe(II) oxidation were examined in air-saturated solution using luminol chemiluminescence technique. The reduction and oxidation rate constants were determined to substantially vary depending on the type of HS. For example, the first-order rate constants varied by up to 10-fold for photochemical reduction and 7-fold for thermal reduction. The degree of variation in Fe(II) oxidation was larger for the H2O2-mediated reaction compared to the O2-mediated reaction (e.g., 15- and 3-fold changes for the former and latter reactions, respectively, at pH 8). The steady-state Fe(II) fraction under the simulated sunlight indicated that the Fe(II) fraction varies by up to 12-fold. The correlation analysis indicated that variation of Fe(II) oxidation is significantly associated with aliphatic content of HS, suggesting that Fe(II) complexation by aliphatic components accelerates Fe(II) oxidation. The reduction rate constant and steady-state Fe(II) fractions in the presence of sunlight had relatively strong positive relations with free radical content of HS, possibly due to the reductive property of radical semiquinone in HS. Overall, the findings in this study indicated that the Fe reduction and oxidation kinetics and resultant Fe(II) formation are substantially influenced by chemical properties of HS.

Inconsistency... or why differentiate, where prevention is concerned, between radioactive substances and carcinogenic chemicals

International Nuclear Information System (INIS)

Choquet, R.; Vinit, J.

1982-01-01

Radiotracers, low-activity unsealed radioactive sources, and certain chemical products belong to the list of substances and agents known to promote cancers in humans. The dangers of radiotracers and carcinogenic chemicals being very similar, or even identical, it is inadmissible that preventive measures have not been equally developed and are not viewed in the same way in our country. It should be noted that the International Labour Bureau has long since included radioactive products in the list of carcinogenic substances and agents and treated preventive measures as a whole by proceeding in this way it would be easier to account for the possible combined effects of ionising radiations and chemical molecules. After a review of some facts about cancer the present situation is examined with regard to statutory measures applied on the one hand to radioelements and on the other to chemicals recognised as carcinogenic by international organisations. Proposals are made to remedy this illogical situation [fr

Modelling of chemical evolution of low pH cements at long term

International Nuclear Information System (INIS)

El Bitouri, Y.; Buffo-Lacarriere, L.; Sellier, A.; Bourbon, X.

2015-01-01

In the context of the underground radioactive waste repository, low-pH cements were developed to reduce interactions between concrete and clay barrier. These cements contain high proportions of mineral additions like silica fume, fly ash or blast furnace slag for example. The high ratio of cement replacement by pozzolanic additions allows to reduce the pH by a global reduction of Ca/Si ratio of the hydrates (according to the one observed on CEM I pastes). In order to predict the short term development of the hydration for each component of this cement, a multiphasic hydration model, previously developed, is used. The model predicts the evolution of hydration degree of each anhydrous phase and consequently the quantity of each hydrate in paste (CH, aluminates, CSH with different Ca/Si ratios). However, this model is not suitable to determine the long term mineralogical and chemical evolution of the material, due to the internal change induced by chemical imbalance between initial hydrates. In order to evaluate the chemical characteristics of low pH cement based materials, and thus assess its chemical stability in the context of radioactive waste storage, a complementary model of chemical evolution at long term is proposed. This original model is based on 'solid-solution' principles. It assumes that the microdiffusion of calcium plays a major role to explain how the different Ca/Si ratio of initial C-S-H tends together toward a medium stabilized value. The main mechanisms and full development of the model equations are presented first. Next, a comparison of the model with experimental data issue from EDS (Energy Dispersive X-ray Spectroscopy) analysis on low pH cement allows to test the model. (authors)

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

International Nuclear Information System (INIS)

Calleja Amador, C.E.

2002-01-01

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) [es

Atividade alelopática de substâncias químicas isoladas do Capim-Marandu e suas variações em função do pH Allelopathic activity of chemical substances isolated from Brachiaria brizantha cv. Marandu and their variations in function of pH

Directory of Open Access Journals (Sweden)

L.S. Santos

2008-01-01

Full Text Available Este trabalho teve por objetivos isolar, identificar e caracterizar a atividade alelopática de substâncias químicas produzidas pela Brachiaria brizantha cv. Marandu e determinar as variações na atividade dessas substâncias em função da variação do pH da solução. A atividade alelopática foi realizada em bioensaios de germinação e desenvolvimento da radícula e do hipocótilo, utilizando as plantas daninhas malícia (Mimosa pudica e mata-pasto (Senna obtusifolia como receptoras. Os efeitos do pH foram analisados na faixa de 3,0 a 9,0. Os triterpenos pentacíclicos friedelina e epifriedelinol isolados da parte aérea de B. brizantha apresentaram baixa atividade inibitória na germinação de sementes e no desenvolvimento da radícula e do hipocótilo das duas plantas daninhas. As duas substâncias apresentaram comportamento diferenciado em relação à variação do pH da solução, com inibições mais marcantes em relação à planta daninha mata-pasto.This work aimed to isolate, identify and determine the allelopathic activity of the chemical substances produced by Brachiaria brizantha cv. Marandu and to verify the effects of the pH in the solution on the activity of these compounds. The allelopathic activity was evaluated based on germination bioassays and radicle and hypocotyl growth using the species 'malícia' (Mimosa pudica and 'mata-pasto' (Senna obtusifolia as receptors. The effect of pH was analyzed in a range from 3.0 to 9.0. The pentacyclic triterpenes friedelin and epifriefelinol isolated from the shoots of B. brizantha showed a low inhibitory activity against seed germination and radicle and hypocotyl growth of the two receptor plants evaluated. The pentacyclic triterpenes friedelin and epifrifelinol presented differentiated behaviors in relation to the pH variation in the solution, with stronger inhibition activity against the weed 'mata-pasto'.

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

International Nuclear Information System (INIS)

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.)

Determination of pH by flow-injection analysis and by fiber-optrode analysis

International Nuclear Information System (INIS)

Pia, S.H.; Waltman, D.P.; Hillman, D.C.

1988-07-01

Two new procedures for measuring pH were developed. The first measures pH colorimetrically using a proprietary indicator-dye mixture in a flow injection analysis (FIA) procedure. The second measures pH using a fiber-optic chemical sensor (FOCS) specifically developed for pH determinations. The FOCS method measures pH by monitoring the fluorescence of a fluorescein derivative bonded to the distal end of a fiber-optic cable called an optrade. The FIA method currently has a precision and accuracy of about + or - 0.2 pH units and can measure 100 samples/hour. The FOCS method has a precision of + or - 0.05-0.20 pH units and an accuracy of + or - 0.1 to 0.6 pH units. About 10 to 60 samples can be analyzed. The characteristics of the FOCS Method will vary significantly with individual optrodes. The experimental results indicate that either flow-injection analysis or fiber optic chemical sensor analysis could form the basis for an alternative to electrometric measurement of pH in certain circumstances

Change of physical and chemical parameters of fulvic acids at different pH of the system

Science.gov (United States)

Dinu, Marina; Kremleva, Tatyana

2017-04-01

Organic substances of humic nature significantly change physicochemical properties at different pH of natural waters. As a consequence, a large number of consecutive and parallel reactions in the structure of organic polymers, and reacting with inorganic anions. The main indicators of changes in the properties of organic acids in natural systems are changes in their IR spectra, changes in the colloid stability (the zeta potential) as well as in the molecular weight and emission spectra (fluorescence emission spectra). The aim of our study was to evaluate of changing in physical and chemical properties of the fulvic acid from soil/water samples in the natural areas of European Russia and Western Siberia (the steppe and the northern taiga zones) at different pH (from 8 to 1.5). Changes in absorption bands of fulvic acid caused by both COOH groups and amino groups with varying degrees of protonation were found. Consequently, we can assume that in an electric field fulvic acid change the sign of their charge at depending on pH. During the lowering of the pH intensity of C-O bands generally decreases, while in the region 1590 cm-1 disappears. In turn, the band at 1700 cm-1 is the most intense; it could mean a complete protonation of the carboxyl groups. According to our data, the values of zeta potential changes depending on pH of the system. The zeta potential becomes more negative with increasing pH and it may be due to ionization of oxygen groups of fulvic acid. For the colloidal polymer systems the value of the zeta potential is strongly negative (less than -20 mV) and strongly positive (over 20 mV) characterize the system as the most stable. Our experimental data for the study of the zeta potential of fulvic acids extracted from the soils and waters of different climatic zones show zonal influence of the qualitative characteristics of organic substances on the surface charge of the high-molecular micelle of fulvic acids. It was found that fulvic acids extracted

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

Energy Technology Data Exchange (ETDEWEB)

Sandoval-Paz, M.G., E-mail: myrnasandoval@udec.cl [Departament of Physics, Faculty of Physical Sciences and Mathematics, University of Concepcion, Box 160-C, Concepción (Chile); Rodríguez, C.A. [Department of Materials Engineering, Faculty of Engineering, University of Concepción, Edmundo Larenas 270, Concepción 4070409 (Chile); Porcile-Saavedra, P.F. [Departament of Physics, Faculty of Physical Sciences and Mathematics, University of Concepcion, Box 160-C, Concepción (Chile); Trejo-Cruz, C. [Department of Physics, Faculty of Science, University of Biobío, Avenue Collao 1202, Box 5C, Concepción 4051381 (Chile)

2016-07-15

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. - Graphical abstract: “Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution” by M. G. Sandoval-Paz, C. A. Rodríguez, P. F. Porcile-Saavedra, C. Trejo-Cruz. Display Omitted - Highlights: • Copper (I) selenide thin films were obtained by chemical bath deposition. • Orthorhombic to cubic phase change was induced by varying the reaction solution pH. • Orthorhombic phase is obtained mainly from a hydroxides cluster mechanism. • Cubic phase is obtained mainly from an ion by ion mechanism. • Structural, optical and electrical properties are presented as a function of pH.

Influence of soil pH on the sorption of ionizable chemicals

DEFF Research Database (Denmark)

Franco, Antonio; Fu, Wenjing; Trapp, Stefan

2009-01-01

, 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 impact of p......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...

Thermal stability of Trichoderma reesei c30 cellulase and aspergillus niger; -glucosidase after ph and chemical modification

Energy Technology Data Exchange (ETDEWEB)

Woodward, J.; Whaley, K.S.; Zachry, G.S.; Wohlpart, D.L.

1981-01-01

Treatment of Trichoderma reesei C30 cellulase at pH 10.0 for 1 h at room temperature increased its pH and thermal stability. Chemical modification of the free epsilon-amino groups of cellulase at pH 10.0 resulted in no further increase in stability. Such chemical modification, however, decreased the thermal stability of the cellulose-cellulase complex. On the contrary, the chemical modification of Aspergillus niger glucosidase with glutaraldehyde at pH 8.0 increased the thermal stability of this enzyme.

Chemical incidents resulted in hazardous substances releases in the context of human health hazards.

OpenAIRE

Palaszewska-Tkacz, Anna; Czerczak, Sławomir; Konieczko, Katarzyna

2017-01-01

Objectives: The research purpose was to analyze data concerning chemical incidents in Poland collected in 1999–2009 in terms of health hazards. Material and Methods: The data was obtained, using multimodal information technology (IT) system, from chemical incidents reports prepared by rescuers at the scene. The final analysis covered sudden events associated with uncontrolled release of hazardous chemical substances or mixtures, which may potentially lead to human exposure. Releases of uniden...

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

Science.gov (United States)

2012-11-02

... 835.5045 or OECD Test Guideline 302A); a UV/visible absorption test (OPPTS Test Guideline 830.7050... precipitate used to produce phosphors. Based on test data on analogous chemical substances, EPA identified...

Effect of medium pH on chemical selectivity of oxalic acid biosynthesis by Aspergillus niger W78C in submerged batch cultures with sucrose as a carbon source.

Science.gov (United States)

Walaszczyk, Ewa; Podgórski, Waldemar; Janczar-Smuga, Małgorzata; Dymarska, Ewelina

2018-01-01

The pH of the medium is the key environmental parameter of chemical selectivity of oxalic acid biosynthesis by Aspergillus niger . The activity of the enzyme oxaloacetate hydrolase, which is responsible for decomposition of oxaloacetate to oxalate and acetate inside the cell of the fungus, is highest at pH 6. In the present study, the influence of pH in the range of 3-7 on oxalic acid secretion by A. niger W78C from sucrose was investigated. The highest oxalic acid concentration, 64.3 g dm -3 , was reached in the medium with pH 6. The chemical selectivity of the process was 58.6% because of the presence of citric and gluconic acids in the cultivation broth in the amount of 15.3 and 30.2 g dm -3 , respectively. Both an increase and a decrease of medium pH caused a decrease of oxalic acid concentration. The obtained results confirm that pH 6 of the carbohydrate medium is appropriate for oxalic acid synthesis by A. niger , but the chemical selectivity of the process described in this paper was high in comparison to values reported previously in the literature.

Tenth anniversary of the Chemical Substances Act. 10 Jahre Chemikaliengesetz; Bilanz und Perspektiven

Energy Technology Data Exchange (ETDEWEB)

Ahlers, J. (Umweltbundesamt, Berlin (Germany)); Arndt, R. (Bundesanstalt fuer Arbeitsschutz, Dortmund (Germany)); Bulling, W.B. (Bundesgesundheitsamt, Berlin (Germany)); Drescher, R.D. (Umweltbundesamt, Berlin (Germany)); Elstner, P. (Bundesgesundheitsamt, Berlin (Germany)); Heinemeyer, G. (Bundesgesundheitsamt, Berlin (Germany)); Kayser, D. (Bundesgesundheitsamt, Berlin (Germany)); Lange, A.W. (

1992-11-01

The chemical substances act is ten years old. These ten years have witnessed a stormy development in legislation on chemicals: what was new ground still at the beginning of the eighties, is now a vast area of law complemented by detailed individual regulations at the administrative level, firmly interlocked with the other areas of environmental law, and part of an overall concept for the safety of chemicals enjoying an international reputation. Currently, the chemical substances act is in a phase of inner consolidation and completion. This phase was ushered in by the proposed amendment of 1990, an amendment aimed to eliminate weak points on the basis of first experiences with the implementation of legal requirements existing under EC law. In the second part of this phase, revisions or completions which have meanwhile been effected or are being effected in community law must be integrated. Further legal regulations are to be expected in the area of prohibitions and restrictions. These are, so far, mainly attuned to individual cases and reactive in nature. Most important of all is the development of a uniform and appropriate catalogue of criteria. The aim must be to create the necessary boundary conditions for the use of chemicals in our industrial society ensuring sustainable, environmentally compatible development for a long time to come. (orig./HSCH)

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.

78 FR 12684 - Proposed Significant New Use Rules on Certain Chemical Substances

Science.gov (United States)

2013-02-25

..., importers, or processors of one or more subject chemical substances (NAICS codes 325 and 324110), e.g... a use changes the type or form of exposure of human beings or the environment to a chemical... assigned in the regulatory text section of this proposed rule. This proposed rule includes 14 PMN...

THE ANALYSIS OF PHYSICO-CHEMICAL PROPERTIES OF TWO UNKNOWN FILTER MATERIALS

Directory of Open Access Journals (Sweden)

Iwona Skoczko

2016-07-01

Full Text Available One of the most important technological processes of water treatment is the process of filtration. Scientists and producers keep on searching new filtration materials which allow for better water purification, are simple in exploitation and do not add chemical substances to the treated water. Therefore, the aim of the present study was to analyze physical and chemical parameters of two unknown porous masses X1 and X2. Such physical parameters as color, granulation, bulk density, the equivalent diameter, the coefficient of uniformity and the porosity of the material were measured and determined. Additionally, the possibility of water treatment was studied during the filtration process in the laboratory tests. Chemical parameters were examined in the water flowing through the mass, such as pH, conductivity and COD-Mn as a general indicator of the content of organic substances in the water. Both studied porous masses were characterized by uniform size of particles. But they were not efficient enough in satisfactory reduction of oxygen consumption. Mass X2 slightly better adsorbed organic substances. It was found that the tested unknown mass filter slightly increase the pH of the filtered water.

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

78 FR 39337 - Importer of Controlled Substances, Notice of Application, Boehringer Ingelheim Chemicals

Science.gov (United States)

2013-07-01

... DEPARTMENT OF JUSTICE Drug Enforcement Administration Importer of Controlled Substances, Notice of Application, Boehringer Ingelheim Chemicals Pursuant to Title 21 Code of Federal Regulations 1301.34(a), this is notice that on May 31, 2013, Boehringer Ingelheim Chemicals, 2820 N. Normandy Drive, Petersburg...

77 FR 43861 - Importer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals

Science.gov (United States)

2012-07-26

... DEPARTMENT OF JUSTICE Drug Enforcement Administration Importer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals Pursuant to Title 21 Code of Federal Regulations 1301.34(a), this is notice that on June 8, 2012, Boehringer Ingelheim Chemicals, Inc., 2820 N. Normandy Drive...

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

Influence of pH during chemical weathering of bricks: Long term exposure

DEFF Research Database (Denmark)

Rörig-Dalgaard, Inge; Charola, A. Elena

2016-01-01

Within the framework of environmental weathering of bricks in historical structures, this study focuses on new bricks currently employed for restoration projects. The bricks were subjected to an accelerated chemical weathering test by immersion in solutions with pH ranging from 3 to 13 for differ...

Radiation decomposition of humic substances in landfill disposal leachate

International Nuclear Information System (INIS)

Sawai, Takeshi; Sawai, Teruko; Shimokawa, Toshinari

1979-01-01

The leachate generated from landfill contains humic substances such as humic acid and fluvic acid. It shows, in general, high chemical oxygen demand (COD) and biological oxygen demand (BOD), and colors in dark brown. When the leachate collected on the No. 15 landfill in Tokyo Bay was irradiated by γ-rays from a 60 Co source in bubbling air, the total organic carbon (TOC) decreased with increasing dose and the brown color was bleached. The effects of pH, flow rate, and dose rate on the decrease of TOC, the variations of UV spectrum, and the formation of carbon dioxide by the irradiation were examined. The decreasing rate of TOC increased with an increase of the flow rate up to -- 11/min and showed a maximum value in the region of pH 4 - 6. It was also dependent on the dose rate and increased with a decrease of the dose rate. The radiation chemical yield, G(-TOC), reached 162 at low dose rate of 1.3 x 10 4 rad/h. This result suggests that a radiation-induced chain reaction occurred. The amount of TOC decreased was almost equal to that of carbon dioxide formed. This result shows that the organic substances were decomposed by irradiation to carbon dioxide as a final product and it was ejected from the solution. (author)

Influence of soil pH on the sorption of ionizable chemicals: modeling advances.

Science.gov (United States)

Franco, Antonio; Fu, Wenjing; Trapp, Stefan

2009-03-01

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 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.

Humic substances as a washing agent for Cd-contaminated soils.

Science.gov (United States)

Meng, Fande; Yuan, Guodong; Wei, Jing; Bi, Dongxue; Ok, Yong Sik; Wang, Hailong

2017-08-01

Cost-effective and eco-friendly washing agents are in demand for Cd contaminated soils. Here, we used leonardite-derived humic substances to wash different types of Cd-contaminated soils, namely, a silty loam (Soil 1), a silty clay loam (Soil 2), and a sandy loam (Soil 3). Washing conditions were investigated for their effects on Cd removal efficiency. Cadmium removal was enhanced by a high humic substance concentration, long washing time, near neutral pH, and large solution/soil ratio. Based on the tradeoff between efficiency and cost, an optimum working condition was established as follows: humic substance concentration (3150 mg C/L), solution pH (6.0), washing time (2 h) and a washing solution/soil ratio (5). A single washing removed 0.55 mg Cd/kg from Soil 1 (1.33 mg Cd/kg), 2.32 mg Cd/kg from Soil 2 (6.57 mg Cd/kg), and 1.97 mg Cd/kg from Soil 3 (2.63 mg Cd/kg). Cd in effluents was effectively treated by adding a small dose of calcium hydroxide, reducing its concentration below the discharge limit of 0.1 mg/L in China. Being cost-effective and safe, humic substances have a great potential to replace common washing agents for the remediation of Cd-contaminated soils. Besides being environmentally benign, humic substances can improve soil physical, chemical, and biological properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

attention. Results The 119,636 journal articles found had 760,056 CAS number links during 2000-2009. The top-20 environmental chemicals consisted of metals, (chlorinated) biphenyls, polyaromatic hydrocarbons, benzene, and ethanol and contributed 12% toward the total number of links- Each of the top-20...... substances was covered by 2,000-10,000 articles during the decade. The numbers for the 10-year period were similar to the total numbers of pre-2000 articles on the same chemicals. However, substances considered a high priority from a regulatory viewpoint, due to lack of documentation, showed very low...

Take control : Developing and testing novel treatments of substance dependence by targeting underlying neurocognitive processes

NARCIS (Netherlands)

Schulte, M.H.J.

2018-01-01

In this PhD project we investigated the effect of N-acetylcysteine (NAC) and working memory (WM) training on substance use, and associated changes in neural correlates of substance dependence. N-acetylcysteine is a glutamatergic agent that reduces craving by restoring the imbalance in the brain

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

Directory of Open Access Journals (Sweden)

Hyunhee Park

2011-03-01

Conclusion: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.

Utilizing Coal Ash and Humic Substances as Soil Ameliorant on Reclaimed Post-Mining Land

Directory of Open Access Journals (Sweden)

Ade Mariyam Oklima

2014-09-01

Full Text Available Coal ash and humic substances can be used as soil ameliorant in the reclamation of formerly mined land. Due to its high pH and nutrients content, coal ash can be used to improve the chemical properties of the soil, such as increasing of pH, and increasing the levels of nutrients availability in the soil. Humic substances may also be used to complement, as they can increase the release of nutrients from the coal ash. Thus, the objective of this study was to assess the influence of coal ash and humic substances on soil chemical characteristics, nutrient absorption, and plant growth. This study was conducted in two locations - in a nursery area, involving two treatment factors: coal ash at different dosages (0, 200, and 400 g polybag-1, and humic material also at varying dosages (0, 0.04, and 0.08 g C polybag-1; and in a post-mining field using similar treatments: coal ash dosage (0, 2.5, and 5.0 kg planting-1 hole and humic material dosage (0, 0.56, and 1.12 g C planting hole-1. The results showed that coal ash and humic materials significantly increased the soil pH, available P, and exchangeable K, Ca and Mg. Coal ash also contained a number of heavy metals but in quantities that are far below the limits set by both Indonesian Government Regulation and the US Environmental Protection Agency (USEPA. The above soil amelioration effects mean that. applicaton of coal ash and humic substances can significantly increase the growth of Jabon trees in the reclaimed post-mining land.

40 CFR 710.25 - Chemical substances for which information must be reported.

Science.gov (United States)

2010-07-01

... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT TSCA CHEMICAL INVENTORY REGULATIONS 2002 Inventory Update Reporting... the Master Inventory File at the beginning of a reporting period described in § 710.33, unless the...

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

International Nuclear Information System (INIS)

Veksler, A.M.; Korystov, Yu.N.; Kublik, L.N.; Ehjdus, L.Kh.

1979-01-01

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

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

Science.gov (United States)

2012-09-21

... Guideline 415); a reproduction and fertility effects test (OECD Test Guideline 416); a reproduction... potentially exposed employees wear specified respirators unless actual measurements of the workplace air show that air-borne concentrations of the PMN substance are below a New Chemical Exposure Limit (NCEL) that...

77 FR 43863 - Manufacturer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals Inc.

Science.gov (United States)

2012-07-26

... DEPARTMENT OF JUSTICE Drug Enforcement Administration Manufacturer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals Inc. Pursuant to Sec. 1301.33(a), Title 21 of the Code of Federal Regulations (CFR), this is notice that on June 8, 2012, Boehringer Ingelheim Chemicals...

78 FR 39340 - Manufacturer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals, Inc.

Science.gov (United States)

2013-07-01

... DEPARTMENT OF JUSTICE Drug Enforcement Administration Manufacturer of Controlled Substances; Notice of Application; Boehringer Ingelheim Chemicals, Inc. Pursuant to Sec. 1301.33(a), Title 21 of the Code of Federal Regulations (CFR), this is notice that on May 31, 2013, Boehringer Ingelheim Chemicals...

Thermal stability of Trichoderma reesei C30 cellulase and Aspergillus niger. beta. -glucosidase after pH and chemical modification

Energy Technology Data Exchange (ETDEWEB)

Woodward, J.; Whaley, K.S.; Zachry, G.S.; Wohlpart, D.L.

1981-01-01

Treatment of Trichoderma reesei C30 cellulase at pH 10.0 for 1 h at room temperature increased its pH and thermal stability. Chemical modification of the free epsilon-amino groups of cellulase at pH 10.0 resulted in no further increase in stability. Such chemical modification, however, decreased the thermal stability of the cellulose-cellulase complex. On the contrary, the chemical modification of Aspergillus niger ..beta..-glucosidase with glutaraldehyde at pH 8.0 increased the thermal stability of this enzyme.

Agronomic performance and soil chemical attributes in a banana tree orchard fertigated with humic substances

Directory of Open Access Journals (Sweden)

Diego Magalhães de Melo

2016-12-01

Full Text Available Fertigation with humic substances products has been adopted in commercial banana tree plantations. However, there are few studies on the procedure to confirm its technical feasibility. This study aimed at assessing the effects of fertigation with humic substances on the chemical attributes of a Dystric Densic Xantic Ferralsol cultivated with the 'BRS Princesa' banana tree cultivar and on the agronomic performance of the orchard. The experiment was conducted using a randomized blocks design, with six treatments and four replications. Treatments consisted of a monthly application of humic substances doses based on the commercially recommended reference dose for the banana plantation (12.09 kg ha-1 cycle-1. The doses used were equivalent to percentages of the reference dose (100 %, 150 %, 200 %, 250 % and 300 %, in addition to the control. No significant effects of the fertigation with humic substances that could justify the use of the product at the doses assessed were observed on the soil chemical attributes, banana growth and yield.

78 FR 40175 - Exempt Chemical Preparations Under the Controlled Substances Act

Science.gov (United States)

2013-07-03

...Standard, Inc M-8270-04-ASL, Method 8270B-- Amber ampule: 1 mL...... 1/28/2013 Base/Neutrals Mix. Accu... CSA and its implementing regulations are designed to prevent, detect, and eliminate the diversion of... controlled substances and listed chemicals for legitimate medical, scientific, research, and industrial...

Explosive (chemical) substances. 6. rev. and enlarged ed. Explosivstoffe

Energy Technology Data Exchange (ETDEWEB)

Meyer, R

1985-01-01

The sixth edition of this review manual again has been enlarged and actualized, the proved concept has been maintained. The text describes in large more than 550 items alphabetically, among them about 120 chemical compounds attributed with structure formulas and data. The properties, preparation procedures, and application possibilities of these substances and of about 70 additives, fuels and oxidants are presented for the reader. By nearly 1500 keywords in the index, English and French translations, and explanations of abbreviations, this book becomes a comprehensive and actual dictionary, not only for the specialist, but also for translators, interpreters, newspaper editors, and patent lawyers. (orig./HK).

COMPARISON BETWEEN SOME PHYSICAL - CHEMICAL CHARACTERISTICS OF CACAO MILK AND RAW MILK

OpenAIRE

Florin Roman

2009-01-01

The paper presents a comparison between some physical - chemical characteristics of the cacao milk and of the raw milk. For this comparison we made the following determinations for both types of milk: the determination of the dry substance using the drying oven with a 102 °C temperature, the determination of the proteic substance by titration with sodium hydroxide ( NaOH ) N/10, the milk pasteurization control by the starch and potassium iodide test and the pH determination using the indicato...

Why the toxic substances control act needs an overhaul, and how to strengthen oversight of chemicals in the interim.

Science.gov (United States)

Vogel, Sarah A; Roberts, Jody A

2011-05-01

The Toxic Substances Control Act gives the Environmental Protection Agency (EPA) the authority to regulate industrial chemicals not covered by other statutes. Today there are more than 83,000 such chemicals. However, the law is widely perceived as weak and outdated, and various stakeholders have called for its reform, citing the EPA's inability to regulate the use of asbestos, among other substances. We analyze the flaws in the act and suggest ways in which the EPA might better position itself to manage chemical risks and protect the public's health. In addition to the new tools and technologies it is adopting, the agency needs new allies-both inside and outside the government-in its efforts to identify and control hazardous chemicals.

Substance Flow Analysis and Source Mapping of Chemical UV-filters

International Nuclear Information System (INIS)

Eriksson, E.; Andersen, H. R.; Ledin, A.

2008-01-01

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

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.

Complexing agents and pH influence on chemical durability of type I moulded glass containers.

Science.gov (United States)

Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

2017-06-16

Among the factors that affect the glass surface chemical durability, pH and complexing agents presence in aqueous solution have the main role (1). Glass surface attack can be also related to the delamination issue with glass particles appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed (2,3). The present study emphasizes the possible synergy between a few complexing agents with pH on the borosilicate glass chemical durability. Hydrolytic attack was performed in small volume 23 ml type I glass containers autoclaved according to EP or USP for 1 hour at 121°C, in order to enhance the chemical attack due to time, temperature and the unfavourable surface/volume ratio. 0,048 M or 0.024 M (moles/liter) solutions of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid) and sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ± 0,05 units at fixed values 5,5-6,6-7-7,4-8-9 by LiOH diluted solution. Since silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by ICPAES. The work was completed by the analysis of the silicon release in the worst attack conditions, of moulded glass, soda lime type II and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by SEM was finally performed to check for the surface status after the worst chemical attack condition by citric acid. Copyright © 2017, Parenteral Drug Association.

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.

High-throughput dietary exposure predictions for chemical migrants from food contact substances for use in chemical prioritization.

Science.gov (United States)

Biryol, Derya; Nicolas, Chantel I; Wambaugh, John; Phillips, Katherine; Isaacs, Kristin

2017-11-01

Under the ExpoCast program, United States Environmental Protection Agency (EPA) researchers have developed a high-throughput (HT) framework for estimating aggregate exposures to chemicals from multiple pathways to support rapid prioritization of chemicals. Here, we present methods to estimate HT exposures to chemicals migrating into food from food contact substances (FCS). These methods consisted of combining an empirical model of chemical migration with estimates of daily population food intakes derived from food diaries from the National Health and Nutrition Examination Survey (NHANES). A linear regression model for migration at equilibrium was developed by fitting available migration measurements as a function of temperature, food type (i.e., fatty, aqueous, acidic, alcoholic), initial chemical concentration in the FCS (C 0 ) and chemical properties. The most predictive variables in the resulting model were C 0 , molecular weight, log K ow , and food type (R 2 =0.71, pchemicals identified via publicly-available data sources as being present in polymer FCSs were predicted for 12 food groups (combinations of 3 storage temperatures and food type). The model was parameterized with screening-level estimates of C 0 based on the functional role of chemicals in FCS. By combining these concentrations with daily intakes for food groups derived from NHANES, population ingestion exposures of chemical in mg/kg-bodyweight/day (mg/kg-BW/day) were estimated. Calibrated aggregate exposures were estimated for 1931 chemicals by fitting HT FCS and consumer product exposures to exposures inferred from NHANES biomonitoring (R 2 =0.61, pchemicals), they can provide critical refinement to aggregate exposure predictions used in risk-based chemical priority-setting. Published by Elsevier Ltd.

Partitioning of uranyl between ferrihydrite and humic substances at acidic and circum-neutral pH

Science.gov (United States)

Dublet, Gabrielle; Lezama Pacheco, Juan; Bargar, John R.; Fendorf, Scott; Kumar, Naresh; Lowry, Gregory V.; Brown, Gordon E.

2017-10-01

As part of a larger study of the reactivity and mobility of uranyl (U(VI)O22+) cations in subsurface environments containing natural organic matter (NOM) and hydrous ferric oxides, we have examined the effect of reference humic and fulvic substances on the sorption of uranyl on 2-line ferrihydrite (Fh), a common, naturally occurring nano-Fe(III)-hydroxide. Uranyl was reacted with Fh at pH 4.6 and 7.0 in the presence and absence of Elliott Soil Humic Acid (ESHA) (0-835 ppm) or Suwanee River Fulvic Acid (SRFA) (0-955 ppm). No evidence was found for reduction of uranyl by either form of NOM after 24 h of exposure. The following three size fractions were considered in this study: (1) ≥0.2 μm (Fh-NOM aggregates), (2) 0.02-0.2 μm (dispersed Fh nanoparticles and NOM macro-molecules), and (3) <0.02 μm (dissolved). The extent to which U(VI) is sorbed in aggregates or dispersed as colloids was assessed by comparing U, Fe, and NOM concentrations in these three size fractions. Partitioning of uranyl between Fh and NOM was determined in size fraction (1) using X-ray absorption spectroscopy (XAS). Uranyl sorption on Fh-NOM aggregates was affected by the presence of NOM in different ways depending on pH and type of NOM (ESHA vs. SRFA). The presence of ESHA in the uranyl-Fh-NOM ternary system at pH 4.6 enhanced uranyl uptake more than the presence of SRFA. In contrast, neither form of NOM affected uranyl sorption at pH 7.0 over most of the NOM concentration range examined (0-500 ppm); at the highest NOM concentrations (500-955 ppm) uranyl uptake in the aggregates was slightly inhibited at pH 7.0, which is interpreted as being due to the dispersion of Fh aggregates. XAS at the U LIII-edge was used to characterize molecular-level changes in uranyl complexation as a result of sorption to the Fh-NOM aggregates. In the absence of NOM, uranyl formed dominantly inner-sphere, mononuclear, bidentate sorption complexes on Fh. However, when NOM concentration was increased at pH 4.6, the

Complexing Agents and pH Influence on Chemical Durability of Type I Molded Glass Containers.

Science.gov (United States)

Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

2017-01-01

Among the factors that affect the glass surface chemical durability, pH and complexing agents present in aqueous solution have the main role. Glass surface attack can be also related to the delamination issue causing glass particles' appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed. The present study emphasizes the possible synergy between a few complexing agents with pH on borosilicate glass chemical durability.Hydrolytic attack was performed in small-volume 23 mL type I glass containers autoclaved according to the European Pharmacopoeia or United States Pharmacopeia for 1 h at 121 °C, in order to enhance the chemical attack due to time, temperature, and the unfavorable surface/volume ratio. Solutions of 0.048 M or 0.024 M (M/L) of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid), together with sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ±0.05 units at fixed values 5.5, 6.6, 7, 7.4, 8, and 9 by LiOH diluted solution.Because silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by inductively coupled plasma atomic emission spectrophotometry. The work was completed by the analysis of the silicon release in the worst attack conditions of molded glass, soda lime type II glass, and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by scanning electron microscopy was finally performed to check for the surface status after the worst chemical attack condition by citric acid. LAY ABSTRACT: Glass, like every packaging material, can have some usage limits, mainly in basic pH solutions. The issue of glass surface degradation particles that appear in vials (delamination) has forced a number of drug product recalls in recent years

40 CFR 710.26 - Chemical substances for which information is not required.

Science.gov (United States)

2010-07-01

... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT TSCA CHEMICAL INVENTORY REGULATIONS 2002 Inventory Update Reporting... Inventory or in the Master Inventory File, where the asterisk (*) indicates that any sets of characters may... 1985 edition of the Inventory or the Master Inventory File as siloxane and silicone, silsesquioxane, a...

CHEMICAL INTERACTIONS TO CLEANUP HIGHLY POLLUTED AUTOMOBILE SERVICE STATION WASTEWATER BY BIOADSORPTION-COAGULATION-FLOCCULATION

Directory of Open Access Journals (Sweden)

Carlos Banchon

2017-01-01

Full Text Available The present study addresses an ecofriendly solution to treat automobile service stations effluents with high concentrations of oily substances, surfactants, organic matter and heavy metals. Bioadsorption using sawdust from pine trees, sugar cane bagasse and coconut coir without any chemical modification removed colloidal contamination up to 70%. Polyaluminium chloride, ferric chloride and polyacrylamide were applied to remove dissolved and colloidal pollutants under saline conditions without change of initial pH. Both bioadsorption and coagulation-flocculation removed up to 97.8% of BOD, COD, surfactants and heavy metals at a saline concentration of 1.5% NaCl. The increase of ionic strength promoted a high sludge index and a representative cost saving in chemicals consumption of almost 70%. High levels of pollution removal with the minimal use of chemicals is herein presented.

78 FR 23184 - Proposed Significant New Use Rules on Certain Chemical Substances

Science.gov (United States)

2013-04-18

.... Potentially affected entities may include: Manufacturers, importers, or processors of one or more subject... manufacturing and processing of a chemical substance. The extent to which a use changes the type or form of... information). CFR citation assigned in the regulatory text section of this proposed rule. The regulatory text...

Determination of the intracellular pH of intact erythrocytes by 1H NMR spectroscopy

International Nuclear Information System (INIS)

Rabenstein, D.L.; Isab, A.A.

1982-01-01

A method is described for determining the intracellular pH of intact erythrocytes by 1 H NMR. The determination is based on the pH dependence of the chemical shifts of resonances for carbon-bounded protons of an indicator molecule (imidazole) in intact cells. The imidazole is introduced into the erythrocytes by incubation in an isotonic saline solution of the indicator. The pH dependence of the chemical shifts of the imidazole resonances is calibrated from 1 H NMR spectra of the imidazole-containing red cell lysates whose pH is varied by the addition of acid or base and measured directly with a pH electrode. To reduce in intensity or eliminate the much more intense envelope of resonances from the hemoglobin, the 1 H NMR measurements are made by either the spin-echo Fourier transform technique or by the transfer-or-saturation by cross-relaxation method

40 CFR 723.50 - Chemical substances manufactured in quantities of 10,000 kilograms or less per year, and chemical...

Science.gov (United States)

2010-07-01

... section 3 of the Act (15 U.S.C. 2602). (4) Environmental transformation product means any chemical... substance, any reasonably anticipated metabolites, environmental transformation products, or byproducts of... EPA under this section which the manufacturer claims to be confidential business information, the...

Chemicalization in water treatment in peat production areas

International Nuclear Information System (INIS)

Madekivi, O.; Marja-Aho, J.; Selin, P.; Jokinen, S.

1995-01-01

Chemicalization of runoff waters of peat production has been studied since 1989, first in laboratory and since 1990 in practice. The methods have been developed as cooperation between Vapo Oy and Kemira Chemicals Oy. In chemicalization the dissolved substances are coagulated and they settle after that into sedimentation basins. Good purification results require rapid and effective mixing, so the formed particles are combined to larger particles, and they form settleable flock. The coagulation efficiency depends on the properties of the water to be purified, such as alkalinity and pH, the quality and the quantity of humic substances, and the quality and the quantity of the flocking chemicals. Chemicalization is at present the most effective, but also the most expensive method for purification of drying waters of peat production areas. The chemicalized water is on the basis of most quality factors cleaner than water running off a virgin bog. The most visible change is the clarification of the water which is due to the coagulation of the colouring humic substances and iron. The colorimetric value is decreased by over 70 %, the best results being over 90 %. The colorimetric value of the purified water (30-100 mg Pt/l) is below the values of the runoff water of a virgin bog (100-200 mg Pt/l). The chemicalization process and the results of the researches are presented in the article. (3 refs., 6 figs., 2 tabs.)

Determination of microscopic interactions between actinides and humic substances

International Nuclear Information System (INIS)

Brunel, Benoit

2015-01-01

Large amount of plutonium has been introduced into the environment as a result of nuclear weapons testing, and nuclear power-plant accidents. Contaminated areas, which need a particular survey, have become a very interesting place to study and understand the plutonium behaviour in the environment. Until few years ago, it was admitted that plutonium introduced into subsurface environment is relatively immobile, owing to its low solubility in ground water and strong sorption onto rocks. However, studies of contaminated areas show that humic substances, which are ubiquitous in environment, can alter the speciation of metal ion, e.g. plutonium, and thus their migration. These humic substances are major components of the natural organic matter in soil and water as well as in geological organic deposits such as lake sediments, peats and brown coals. They are complex heterogeneous mixtures of polydisperse supra-molecules formed by biochemical and chemical reactions during the decay and transformation of plant and microbial remains. The knowledge of the impact of humic substances on the plutonium migration is required to assess their transport in natural systems. However, due to the complex and heterogeneous nature of humic substances, there are a lot of difficulties in the description of microscopic interactions. The aim of this PhD thesis is to evaluate as precisely as possible interactions between actinides and humic substances. This work is divided in two parts: on the one hand humic substances will be separated to identify each component, on the other hand the speciation of actinides with characterized humic substances will be studied. In the first part of this study, new methods are developed to study the speciation of actinides with humic substances using two kinds of mass spectrometers: an ICP-MS and a high resolution mass spectrometer using various ionization devices (ESI, APCI, DART, APPI) in order to determine all active molecules for the complexation. In the

Surface Chemical Characterisation of Pyrite Exposed to Acidithiobacillus ferrooxidans and Associated Extracellular Polymeric Substances

Directory of Open Access Journals (Sweden)

Sian M. La Vars

2018-03-01

Full Text Available A. ferrooxidans and their metabolic products have previously been explored as a viable alternative depressant of pyrite for froth flotation; however, the mechanism by which separation is achieved is not completely understood. Scanning electron microscopy (SEM, photoemission electron microscopy (PEEM, time-of-flight secondary ion mass spectrometry (ToF-SIMS and captive bubble contact angle measurements have been used to examine the surface physicochemical properties of pyrite upon exposure to A. ferrooxidans grown in HH medium at pH 1.8. C K-edge near edge X-ray absorption fine structure (NEXAFS spectra collected from PEEM images indicate hydrophilic lipids, fatty acids and biopolymers are formed at the mineral surface during early exposure. After 168 h, the spectra indicate a shift towards protein and DNA, corresponding to an increase in cell population and biofilm formation on the surface, as observed by SEM. The Fe L-edge NEXAFS show gradual oxidation of the mineral surface from Fe(II sulfide to Fe(III oxyhydroxides. The oxidation of the iron species at the pyrite surface is accelerated in the presence of A. ferrooxidans and extracellular polymeric substances (EPS as compared to HH medium controls. The surface chemical changes induced by the interaction with A. ferrooxidans show a significant decrease in surface hydrophobicity within the first 2 h of exposure. The implications of these findings are the potential use of EPS produced during early attachment of A. ferrooxidans, as a depressant for bioflotation.

40 CFR 799.5000 - Testing consent orders for substances and mixtures with Chemical Abstract Service Registry Numbers.

Science.gov (United States)

2010-07-01

... section sets forth a list of substances and mixtures which are the subject of testing consent orders... the substances and mixtures which are the subject of these orders and the Federal Register citations... Crotonaldehyde Environmental effects November 9, 1989. Chemical fate November 9, 1989. 4675-54-3 Bisphenol A...

HYDROLYSIS OF STARCH BY THERMO-AND PH-STABLE GLUCOAMYLASE AT CHANGE PHYSICO-CHEMICAL FACTORS

Directory of Open Access Journals (Sweden)

V. S. Grigirov

2013-01-01

Full Text Available Regularity of the change rate of the enzymatic reactions depending on different temperatures, pH values in the formation and decay of the enzyme-substrate complex was investigated. Found that the kinetics of hydrolysis of starch by the action of heat and pH stable glucoamylases is complex as evidenced by the change in the value Km, which is a measure of the affinity of the enzyme to the substrate, active centers studied glucoamylases and starch undergo conformational changes at pH 4,0-5,0; 4,5-5,5 and a temperature of 60-65 °C.

Behavior of phenolic substances in the decaying process of plants. V. Elution of heavy metals with phenolic acids from soil

Energy Technology Data Exchange (ETDEWEB)

Shindo, H; Kuwatsuka, S

1977-01-01

The relationship between the elution of heavy metals with phenolic substances and the chemical structure of phenolic substances, as well as the interaction between phenolic substances and metals were studied using batch and column methods. The elution of 3 metals (Fe, Al and Mn) with 4 phenolic acids (rho-hydroxybenzoic, salicylic, ..cap alpha..-resorcylic, and protocatechuic acids) and phthalic acid were investigated using 3 different soils. The results are as follows: (1) The elution of heavy metals was largely influenced by the chemical structures of the phenolic acids. Protocatechuic, salicylic, and phthalic acids which had different chelating sites easily extracted iron, aluminum, and manganese from the soils. Hydroxybenzoic and ..cap alpha..-resorcylic acids which had no chelating sites contributed little to the elution process. (2) In many cases protocatechuic acid showed a stronger affinity to iron than to aluminum, but salicylic acid showed the opposite trend. The affinity of phthalic acid to metals was much less than that of both phenolic acids. (3) The elution of heavy metals was also influenced by the soil pH. The amounts of heavy metals eluted with protocatechuic acid increased as the soil pH increased. The amounts eluted with salicylic and phthalic acids increased as the soil pH decreased. (4) The results suggested that chelating phenolics such as protocatechuic and salicylic acids, which were exuded from plant residues or produced during the decaying process of plant residues, eluted heavy metals such as iron, aluminum and manganese from soil particles and accelerated the downward movement of these metal ions.

Chemical Speciation and Bond Lengths of Organic Solutes by Core-Level Spectroscopy: pH and Solvent Influence on p-Aminobenzoic Acid.

Science.gov (United States)

Stevens, Joanna S; Gainar, Adrian; Suljoti, Edlira; Xiao, Jie; Golnak, Ronny; Aziz, Emad F; Schroeder, Sven L M

2015-05-04

Through X-ray absorption and emission spectroscopies, the chemical, electronic and structural properties of organic species in solution can be observed. Near-edge X-ray absorption fine structure (NEXAFS) and resonant inelastic X-ray scattering (RIXS) measurements at the nitrogen K-edge of para-aminobenzoic acid reveal both pH- and solvent-dependent variations in the ionisation potential (IP), 1s→π* resonances and HOMO-LUMO gap. These changes unequivocally identify the chemical species (neutral, cationic or anionic) present in solution. It is shown how this incisive chemical state sensitivity is further enhanced by the possibility of quantitative bond length determination, based on the analysis of chemical shifts in IPs and σ* shape resonances in the NEXAFS spectra. This provides experimental access to detecting even minor variations in the molecular structure of solutes in solution, thereby providing an avenue to examining computational predictions of solute properties and solute-solvent interactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The pH Game.

Science.gov (United States)

Chemecology, 1996

1996-01-01

Describes a game that can be used to teach students about the acidity of liquids and substances around their school and enable them to understand what pH levels tell us about the environment. Students collect samples and measure the pH of water, soil, plants, and other natural material. (DDR)

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

Analyses of the Erosive Effect of Dietary Substances and Medications on Deciduous Teeth.

Science.gov (United States)

Lussi, Adrian; Carvalho, Thiago Saads

2015-01-01

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 -pI)HAP, (pK -pI)FAP, and (pK-pI)CaF2) 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

Cruel disease, cruel medicine: self-treatment of cutaneous leishmaniasis with harmful chemical substances in Suriname.

Science.gov (United States)

Ramdas, Sahienshadebie

2012-09-01

Why are potentially harmful, non-biomedical chemical substances, such as battery acid, chlorine, herbicides, and insecticides, used in the treatment of cutaneous leishmaniasis (CL)? What drives people to use these products as medicine? This article is about perceptions of CL, and the quest for a cure, in Suriname, South America. It highlights the associative style of reasoning behind health seeking and discusses the use of harmful chemical substances as medicines. Cutaneous leishmaniasis, a parasitic disease, affects 1 to 1.5 million people globally. It has a spectrum of clinical manifestations, but the most prominent and disfiguring elements are extensive dermatological ulceration and scar formation from lesions. The data upon which this article is based are derived from anthropological research carried out in different parts of Suriname between September 2009 and December 2010. Data was collected through mainly qualitative methods, including interviewing 205 CL patients using structured questionnaires at the Dermatological Service in the capital Paramaribo. Almost all people with CL said they tried self-treatment, varying from the use of ethno-botanical products to non-biomedical chemical solutions. This article presents and interprets the views and practices of CL patients who sought treatment using harsh chemicals. It argues that a confluence of contextual factors - environmental, occupational, infrastructural, geographical, socio-cultural, economic, socio-psychological - leads to the use of harmful chemical substances to treat CL sores. This study is the first in Suriname - and one of the few done globally - focusing on social and cultural aspects related to CL health seeking. It aims to encourage health policy makers and health professionals to carefully initiate, provide, and evaluate CL treatment and prevention programs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Calcium carbonate formation on mica supported extracellular polymeric substance produced by Rhodococcus opacus

Energy Technology Data Exchange (ETDEWEB)

Szcześ, Aleksandra, E-mail: aszczes@poczta.umcs.lublin.pl [Department of Physical Chemistry – Interfacial Phenomena, Faculty of Chemistry, Maria Curie-Skłodowska University, Lublin 20-031 (Poland); Czemierska, Magdalena; Jarosz-Wilkołazka, Anna [Department of Biochemistry, Maria Curie-Skłodowska University, Lublin 20-031 (Poland)

2016-10-15

Extracellular polymeric substance (EPS) extracted from Rhodococcus opacus bacterial strain was used as a matrix for calcium carbonate precipitation using the vapour diffusion method. The total exopolymer and water-soluble exopolymer fraction of different concentrations were spread on the mica surface by the spin-coating method. The obtained layers were characterized using the atomic force microscopy measurement and XPS analysis. The effects of polymer concentration, initial pH of calcium chloride solution and precipitation time on the obtained crystals properties were investigated. Raman spectroscopy and scanning electron microscopy were used to characterize the precipitated minerals. It was found that the type of precipitated CaCO{sub 3} polymorph and the crystal size depend on the kind of EPS fraction. The obtained results indicates that the water soluble fraction favours vaterite dissolution and calcite growth, whereas the total EPS stabilizes vaterite and this effect is stronger at basic pH. It seems to be due to different contents of the functional group of EPS fractions. - Highlights: • CaCO{sub 3} crystal size and polymorph can be controlled by EPS substance obtained from R. opacus. • The water soluble fraction favours vaterite dissolution and calcite growth. • The total EPS stabilizes vaterite. • This effect is stronger at basic pH.

Calcium carbonate formation on mica supported extracellular polymeric substance produced by Rhodococcus opacus

International Nuclear Information System (INIS)

Szcześ, Aleksandra; Czemierska, Magdalena; Jarosz-Wilkołazka, Anna

2016-01-01

Extracellular polymeric substance (EPS) extracted from Rhodococcus opacus bacterial strain was used as a matrix for calcium carbonate precipitation using the vapour diffusion method. The total exopolymer and water-soluble exopolymer fraction of different concentrations were spread on the mica surface by the spin-coating method. The obtained layers were characterized using the atomic force microscopy measurement and XPS analysis. The effects of polymer concentration, initial pH of calcium chloride solution and precipitation time on the obtained crystals properties were investigated. Raman spectroscopy and scanning electron microscopy were used to characterize the precipitated minerals. It was found that the type of precipitated CaCO 3 polymorph and the crystal size depend on the kind of EPS fraction. The obtained results indicates that the water soluble fraction favours vaterite dissolution and calcite growth, whereas the total EPS stabilizes vaterite and this effect is stronger at basic pH. It seems to be due to different contents of the functional group of EPS fractions. - Highlights: • CaCO 3 crystal size and polymorph can be controlled by EPS substance obtained from R. opacus. • The water soluble fraction favours vaterite dissolution and calcite growth. • The total EPS stabilizes vaterite. • This effect is stronger at basic pH.

Characterization of Bacteriocin like inhibitory substance produced by a new Strain Brevibacillus borstelensis AG1 Isolated from 'Marcha'.

Science.gov (United States)

Sharma, Nivedita; Gupta, Anupama; Gautam, Neha

2014-01-01

In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative.

The relevance of the food production chain with regard to the population exposure to chemical substances and its role in contaminated sites.

Science.gov (United States)

Mancini, Francesca Romana; Busani, Luca; Tait, Sabrina; La Rocca, Cinzia

2016-01-01

Food may be contaminated with many chemical substances at any level along the production chain. Chemicals that may be found in food items can simultaneously be present in other matrices, as air, water, soil and dust; therefore, human exposure to chemicals via food has to be summed to the exposure through all the other possible routes. The role played by the food production chain with regard to the population exposure to chemicals assumes amplified proportions when considering contaminated sites. Indeed the link between environment and food production is undeniable and consequently, when population chemical exposure is considered, an integrated approach assessing the contribution of the different routes of exposure, including dietary exposure, is needed. Such integrated approach allows a realistic and comprehensive risk assessment of chemical substances in order to identify and deploy effective prevention and intervention measures to protect human health.

A comparative study of changes in immunological reactivity during prolonged introduction of radioactive and chemical substances into the organism with drinking water

International Nuclear Information System (INIS)

Shubik, V.M.; Nevstrueva, M.A.; Kalnitskij, S.A.; Livshits, R.E.; Merkushev, G.N.; Pilshchik, E.M.; Ponomareva, T.V.

1978-01-01

A comparative study was conducted into the factors of non-specific protection and specific immunity, allergic and autoallergic reactivities during prolonged exposure of experimental animals to 6 different radioactive and 7 harmful chemical substances. Qualitative and quantitative peculiarities were found in the changes in immunological reactivity during the exposure of the organism to radionuclides and stable chemical compounds. Impairment of immunity plays an essential role in the course and the outcome of effects induced by chronic action of the substances examined. (author)

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

International Nuclear Information System (INIS)

Bosselmann, K.; Linden, W.

1989-01-01

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) [de

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.

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

impact approaches, i.e. the assessment factor-based PNEC approach and the PAF-based approach, shows pros and cons for both. However, taking the comparative nature of LCA and its aim for best estimate into account, and combining this with the possibilities for reducing the data demand of an EC50-based PAF......Life cycle assessment (LCA) studies on products or services seem generally to be carried out without a proper inclusion of potential toxic impacts from emissions of chemicals. The first goal of the thesis is to investigate this statement and to clarify whether or not the outcome of an LCA can...... of 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...

Improvement of sludge dewaterability and removal of sludge-borne metals by bioleaching at optimum pH.

Science.gov (United States)

Liu, Fenwu; Zhou, Lixiang; Zhou, Jun; Song, Xingwei; Wang, Dianzhan

2012-06-30

Bio-acidification caused by bio-oxidation of energy substances during bioleaching is widely known to play an important role in improving sludge-borne metals removal. Here we report that bioleaching also drastically enhances sludge dewaterability in a suitable pH level. To obtain the optimum initial concentrations of energy substances and pH values for sludge dewaterability during bioleaching, bio-oxidation of Fe(2+) and S(0) under co-inoculation with Acidithiobacillus thiooxidans TS6 and Acidothiobacillus ferrooxidans LX5 and their effects on sludge dewaterability and metals removal during sludge bioleaching were investigated. Results indicated that the dosage of energy substances with 2g/L S(0) and 2g/L Fe(2+) could obtain bio-oxidation efficiencies of up to 100% for Fe(2+) and 50% for S(0) and were the optimal dosages for sludge bioleaching. The removal efficiencies of sludge-borne Cu and Cr could reach above 85% and 40%, respectively, and capillary suction time (CST) of bioleached sludge decreased to as low as ∼10s from initial 48.9s for fresh sludge when sludge pH declined to ∼2.4 through bioleaching. These results confirm the potential of bioleaching as a novel method for improving sludge dewaterability as well as removal of metals. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparative evaluation of tooth substance loss and its correlation with the abrasivity and chemical composition of different dentifrices.

Science.gov (United States)

Singh, Ram Prakash; Sharma, Sidhartha; Logani, Ajay; Shah, Naseem; Singh, Surendra

2016-01-01

In India, teeth cleaning with tooth powder is common in rural and semi-urban areas. These dentifrices may contain low-quality abrasives, which may have a deleterious effect on dental hard tissues. This study aims to evaluate the tooth substance loss caused by different dentifrices and to correlate it with chemical composition, size, and shape of abrasives used. An indigenously made automated machine was used for brushing the specimens. Sixty-four freshly extracted premolars were allocated to eight groups (n = 8). Colgate toothpaste was used as the control group. Each specimen was brushed in a vertical motion for 2½ h at 200 strokes/min with a constant applied load of 200 g corresponding to 6-month brushing. The difference in weight (pre- and post-brushing) was determined by an analytical weighing machine. Chemical analysis was done to determine the presence of iron oxide by Inductively Coupled Plasma Mass Spectrometry method. Shape and size of the abrasive particles was evaluated under scanning electron microscopy (SEM). One-way analysis of variance and Paired t-test were used to analyze the data. Tooth substance loss was maximum in the group brushed with red tooth powder, which was shown to contain the highest amount of iron oxide and also exhibited large, irregularly shaped abrasive particles under SEM. Tooth substance loss was documented to be correlated with chemical composition (iron oxide) and the size and shape of abrasive particles used in dentifrices.

Characterization of Bacteriocin like inhibitory substance produced by a new Strain Brevibacillus borstelensis AG1 Isolated from ‘Marcha’

Science.gov (United States)

Sharma, Nivedita; Gupta, Anupama; Gautam, Neha

2014-01-01

In the present study, a bacterium isolated from Marcha- a herbal cake used as traditional starter culture to ferment local wine in North East India, was evaluated for bacteriocin like inhibitory substance production and was tested against six food borne/spoilage causing pathogens viz. Listeria monocytogenes MTCC 839, Bacillus subtilis MTCC 121, Clostridium perfringens MTCC 450, Staphylococcus aureus, Lactobacillus plantarum and Leuconostoc mesenteroides MTCC 107 by using bit/disc method followed by well diffusion method. The bacterial isolate was identified as Brevibacillus borstelensis on the basis of phenotypic, biochemical and molecular characteristics using 16Sr RNA gene technique. Bacteriocin like inhibitory substance produced by Brevibacillus borstelensis AG1 was purified by gel exclusion chromatography. The molecular mass of the Brevibacillus borstelensis AG1 was found to be 12 kDa. Purified bacteriocin like inhibitory substance of Brevibacillus borstelensis was further characterized by studying the effect of temperature, pH, proteolytic enzyme and stability. Bacteriocin like inhibitory substance was found to be thermostable upto 100 °C, active at neutral pH, sensitive to trypsin, and partially stable till third week of storage thus showing a bright prospective to be used as a potential food biopreservative. PMID:25477937

Effects of pH and temperature on the deposition properties of stannate chemical conversion coatings formed by the potentiostatic technique on AZ91 D magnesium alloy

International Nuclear Information System (INIS)

Elsentriecy, Hassan H.; Azumi, Kazuhisa; Konno, Hidetaka

2008-01-01

The effects of pH and temperature of a stannate bath on the quality of stannate chemical conversion coatings formed on AZ91 D magnesium alloy by using the potentiostatic polarization technique at E = -1.1 V were investigated in order to improve uniformity and corrosion protection performance of the coating films. It was found that the uniformity and corrosion resistance of coating films deposited by potentiostatic polarization were closely associated with pH and temperature of the coating bath. The pH and temperature to obtain the best coating film were investigated as a function of corrosion protection performance evaluated by curves of potentiodynamic anodic polarization conducted in borate buffer solution. Scanning electron microscope observation and electrochemical corrosion tests of the stannate-coated samples confirmed significant improvement in uniformity and corrosion resistivity of coating films deposited by the potentiostatic technique by modifying the pH and temperature of the coating bath. It was also found that uniformity and corrosion resistivity of the coating films deposited by the potentiostatic technique were considerably improved compared to those of coatings deposited by the simple immersion method at the best conditions of pH and temperature of the coating bath

Assessing mine drainage pH from the color and spectral reflectance of chemical precipitates

Science.gov (United States)

Williams, D.J.; Bigham, J.M.; Cravotta, C.A.; Traina, S.J.; Anderson, J.E.; Lyon, J.G.

2002-01-01

The pH of mine impacted waters was estimated from the spectral reflectance of resident sediments composed mostly of chemical precipitates. Mine drainage sediments were collected from sites in the Anthracite Region of eastern Pennsylvania, representing acid to near neutral pH. Sediments occurring in acidic waters contained primarily schwertmannite and goethite while near neutral waters produced ferrihydrite. The minerals comprising the sediments occurring at each pH mode were spectrally separable. Spectral angle difference mapping was used to correlate sediment color with stream water pH (r2=0.76). Band-center and band-depth analysis of spectral absorption features were also used to discriminate ferrihydrite and goethite and/or schwertmannite by analyzing the 4T1??? 6A1 crystal field transition (900-1000 nm). The presence of these minerals accurately predicted stream water pH (r2=0.87) and provided a qualitative estimate of dissolved SO4 concentrations. Spectral analysis results were used to analyze airborne digital multispectral video (DMSV) imagery for several sites in the region. The high spatial resolution of the DMSV sensor allowed for precise mapping of the mine drainage sediments. The results from this study indicate that airborne and space-borne imaging spectrometers may be used to accurately classify streams impacted by acid vs. neutral-to-alkaline mine drainage after appropriate spectral libraries are developed.

Fertilization Shapes Bacterial Community Structure by Alteration of Soil pH

Directory of Open Access Journals (Sweden)

Yuting Zhang

2017-07-01

Full Text Available Application of chemical fertilizer or manure can affect soil microorganisms directly by supplying nutrients and indirectly by altering soil pH. However, it remains uncertain which effect mostly shapes microbial community structure. We determined soil bacterial diversity and community structure by 454 pyrosequencing the V1-V3 regions of 16S rRNA genes after 7-years (2007–2014 of applying chemical nitrogen, phosphorus and potassium (NPK fertilizers, composted manure or their combination to acidic (pH 5.8, near-neutral (pH 6.8 or alkaline (pH 8.4 Eutric Regosol soil in a maize-vegetable rotation in southwest China. In alkaline soil, nutrient sources did not affect bacterial Operational Taxonomic Unit (OTU richness or Shannon diversity index, despite higher available N, P, K, and soil organic carbon in fertilized than in unfertilized soil. In contrast, bacterial OTU richness and Shannon diversity index were significantly lower in acidic and near-neutral soils under NPK than under manure or their combination, which corresponded with changes in soil pH. Permutational multivariate analysis of variance showed that bacterial community structure was significantly affected across these three soils, but the PCoA ordination patterns indicated the effect was less distinct among nutrient sources in alkaline than in acidic and near-neural soils. Distance-based redundancy analysis showed that bacterial community structures were significantly altered by soil pH in acidic and near-neutral soils, but not by any soil chemical properties in alkaline soil. The relative abundance (% of most bacterial phyla was higher in near-neutral than in acidic or alkaline soils. The most dominant phyla were Proteobacteria (24.6%, Actinobacteria (19.7%, Chloroflexi (15.3% and Acidobacteria (12.6%; the medium dominant phyla were Bacterioidetes (5.3%, Planctomycetes (4.8%, Gemmatimonadetes (4.5%, Firmicutes (3.4%, Cyanobacteria (2.1%, Nitrospirae (1.8%, and candidate division TM7 (1

Fertilization Shapes Bacterial Community Structure by Alteration of Soil pH.

Science.gov (United States)

Zhang, Yuting; Shen, Hong; He, Xinhua; Thomas, Ben W; Lupwayi, Newton Z; Hao, Xiying; Thomas, Matthew C; Shi, Xiaojun

2017-01-01

Application of chemical fertilizer or manure can affect soil microorganisms directly by supplying nutrients and indirectly by altering soil pH. However, it remains uncertain which effect mostly shapes microbial community structure. We determined soil bacterial diversity and community structure by 454 pyrosequencing the V1-V3 regions of 16S rRNA genes after 7-years (2007-2014) of applying chemical nitrogen, phosphorus and potassium (NPK) fertilizers, composted manure or their combination to acidic (pH 5.8), near-neutral (pH 6.8) or alkaline (pH 8.4) Eutric Regosol soil in a maize-vegetable rotation in southwest China. In alkaline soil, nutrient sources did not affect bacterial Operational Taxonomic Unit (OTU) richness or Shannon diversity index, despite higher available N, P, K, and soil organic carbon in fertilized than in unfertilized soil. In contrast, bacterial OTU richness and Shannon diversity index were significantly lower in acidic and near-neutral soils under NPK than under manure or their combination, which corresponded with changes in soil pH. Permutational multivariate analysis of variance showed that bacterial community structure was significantly affected across these three soils, but the PCoA ordination patterns indicated the effect was less distinct among nutrient sources in alkaline than in acidic and near-neural soils. Distance-based redundancy analysis showed that bacterial community structures were significantly altered by soil pH in acidic and near-neutral soils, but not by any soil chemical properties in alkaline soil. The relative abundance (%) of most bacterial phyla was higher in near-neutral than in acidic or alkaline soils. The most dominant phyla were Proteobacteria (24.6%), Actinobacteria (19.7%), Chloroflexi (15.3%) and Acidobacteria (12.6%); the medium dominant phyla were Bacterioidetes (5.3%), Planctomycetes (4.8%), Gemmatimonadetes (4.5%), Firmicutes (3.4%), Cyanobacteria (2.1%), Nitrospirae (1.8%), and candidate division TM7 (1

Effect of humic substances on phosphorus removal by struvite precipitation.

Science.gov (United States)

Zhou, Zhen; Hu, Dalong; Ren, Weichao; Zhao, Yuzeng; Jiang, Lu-Man; Wang, Luochun

2015-12-01

Humic substances (HS) are a major fraction of dissolved organic matters in wastewater. The effect of HS on phosphorus removal by struvite precipitation was investigated using synthetic wastewater under different initial pH values, Mg/P molar ratios and HS concentrations. The composition, morphology and thermal properties of harvested precipitates were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM) and thermo-gravimetric analysis (TGA), respectively. It showed that inhibition effect of HS reached its maximum value of 48.9% at pH 8.0, and decreased to below 10% at pH>9.0. The increase of Mg/P ratio enhanced phosphorus removal efficiency, and thus reduced the influence of HS on struvite precipitation. At pH 9.0, the inhibitory effect of initial HS concentration matched the modified Monod model with half maximum inhibition concentration of 356mgL(-1), and 29% HS was removed in conjunction with struvite crystallisation. XRD analysis revealed that the crystal form of struvite precipitates was changed in the presence of HS. The morphology of harvested struvite was transformed from prismatic to pyramid owing to the coprecipitation of HS on crystal surface. TGA results revealed that the presence of HS could compromise struvite purity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Direct measurement of the fluorescence characteristics of aquatic humic substances by a three-dimensional fluorescence spectrophotometer

International Nuclear Information System (INIS)

Nagao, Seiya; Senoo, Muneaki; Suzuki, Yasuhiro; Nakaguchi, Yuzuru; Hiraki, Keizo.

1997-01-01

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)

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.)

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

International Nuclear Information System (INIS)

Pivovarov, A.; Kravchenko, A.; Kublanovsky, V.

2009-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Pivovarov, A; Kravchenko, A [Ukrainian State University of Chemical Engineering, Dnepropetrovsk (Ukraine); Kublanovsky, V [V. I. Vernadsky Institute of General and Inorganic Chemistry of National Academy of Science, Kiev (Ukraine)

2009-07-01

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

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

International Nuclear Information System (INIS)

Obana, Hirotaka; Nakamura, Sei-ichi; Tanaka, Ryou-ichi

1986-01-01

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.)

Thermal, chemical and pH induced unfolding of turmeric root lectin: modes of denaturation.

Directory of Open Access Journals (Sweden)

Himadri Biswas

Full Text Available Curcuma longa rhizome lectin, of non-seed origin having antifungal, antibacterial and α-glucosidase inhibitory activities, forms a homodimer with high thermal stability as well as acid tolerance. Size exclusion chromatography and dynamic light scattering show it to be a dimer at pH 7, but it converts to a monomer near pH 2. Circular dichroism spectra and fluorescence emission maxima are virtually indistinguishable from pH 7 to 2, indicating secondary and tertiary structures remain the same in dimer and monomer within experimental error. The tryptophan environment as probed by acrylamide quenching data yielded very similar data at pH 2 and pH 7, implying very similar folding for monomer and dimer. Differential scanning calorimetry shows a transition at 350.3 K for dimer and at 327.0 K for monomer. Thermal unfolding and chemical unfolding induced by guanidinium chloride for dimer are both reversible and can be described by two-state models. The temperatures and the denaturant concentrations at which one-half of the protein molecules are unfolded, are protein concentration-dependent for dimer but protein concentration-independent for monomer. The free energy of unfolding at 298 K was found to be 5.23 Kcal mol-1 and 14.90 Kcal mol-1 for the monomer and dimer respectively. The value of change in excess heat capacity upon protein denaturation (ΔCp is 3.42 Kcal mol-1 K-1 for dimer. The small ΔCp for unfolding of CLA reflects a buried hydrophobic core in the folded dimeric protein. These unfolding experiments, temperature dependent circular dichroism and dynamic light scattering for the dimer at pH 7 indicate its higher stability than for the monomer at pH 2. This difference in stability of dimeric and monomeric forms highlights the contribution of inter-subunit interactions in the former.

78 FR 27860 - Revocation of TSCA Section 4 Testing Requirements for One High Production Volume Chemical Substance

Science.gov (United States)

2013-05-13

... unit for this chemical substance are no longer supported. III. Amendment to Chemical Testing... proposed rule document (Ref. 4). The EDF comment indicated support for the May 14, 2012 Federal Register.... Fresh Water Algal Growth Inhibition Test with C.I. Pigment Blue 61 study. Submitted on April 13, 2012...

Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

Science.gov (United States)

Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

2010-11-15

A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

Top five industries resulting in injuries from acute chemical incidents—Hazardous Substance Emergency Events Surveillance, nine states, 1999-2008.

Science.gov (United States)

Anderson, Ayana R; Wu, Jennifer

2015-04-10

Because industries using and/or producing chemicals are located in close proximity to populated areas, U.S. residents are at risk for unintentional chemical exposures. 1999-2008. The Hazardous Substances Emergency Events Surveillance (HSEES) system was operated by the Agency for Toxic Substances and Disease Registry during January 1991-September 2009 to collect data that would enable researchers to describe the public health consequences of chemical releases and to develop activities aimed at reducing the harm from such releases. This report summarizes data for the top five industries resulting in injuries from an acute chemical incident (lasting truck transportation, educational services, chemical manufacturing, utilities, and food manufacturing) accounted for approximately one third of all incidents in which persons were injured as a result of unintentional release of chemicals; the same five industries were responsible for approximately one third of all persons injured as a result of such releases. Acute chemical incidents in these five industries resulted in serious public health implications including the need for evacuations, morbidity, and mortality. PUBLIC HEALTH IMPLICATIONS: Targeting chemical incident prevention and preparedness activities towards these five industries provides an efficient use of resources for reducing chemical exposures. A variety of methods can be used to minimize chemical releases in industries. One example is the Occupational Safety and Health Administration's hierarchy of controls model, which focuses on controlling exposures to occupational hazards. The hierarchy includes elimination, substitution, engineering controls, administrative controls, and use of personal protective equipment.

The legal changes regarding chemical protection used by amateurs, available active substances and the expected impact on the development of pest resistance in Poland

Directory of Open Access Journals (Sweden)

Ewa Matyjaszczyk

2015-06-01

Full Text Available Beginning from June 2015, non-professionals will be allowed to only buy and use plant protection products bearing information on the label that they are intended for use by non-professionals. Based on the current register and derogations, the following products will be available for use by amateurs: 21 fungicides, 30 insecticides and 15 herbicides with respectively 20, 14 and 9 different active substances. Over a third of the mentioned active substances of fungicides and insecticides are classified as “high risk” in terms of probability of pest resistance development. For numerous uses only a single product is available. The area of home gardens in Poland amounts to 53.5 thousand hectares. Sales of plant protection products for use by amateurs is about 7% of the market value. The very limited availability of chemical plant protection products for non-professionals can be a serious problem if seen from the perspective of pest resistance development and dissemination. Resistant pests may also affect farms with commercial production. Poland is an important producer of a variety of fruits, vegetables and ornamental plants with a very limited availability of chemical protection. Resistance development can further reduce the practical means of pest control and became a serious economic problem.

Sorption of perfluoroalkyl substances (PFASs) to an organic soil horizon - Effect of cation composition and pH.

Science.gov (United States)

Campos Pereira, Hugo; Ullberg, Malin; Kleja, Dan Berggren; Gustafsson, Jon Petter; Ahrens, Lutz

2018-09-01

Accurate prediction of the sorption of perfluoroalkyl substances (PFASs) in soils is essential for environmental risk assessment. We investigated the effect of solution pH and calculated soil organic matter (SOM) net charge on the sorption of 14 PFASs onto an organic soil as a function of pH and added concentrations of Al 3+ , Ca 2+ and Na + . Often, the organic C-normalized partitioning coefficients (K OC ) showed a negative relationship to both pH (Δlog K OC /ΔpH = -0.32 ± 0.11 log units) and the SOM bulk net negative charge (Δlog K OC  = -1.41 ± 0.40 per log unit mol c g -1 ). Moreover, perfluorosulfonic acids (PFSAs) sorbed more strongly than perfluorocarboxylic acids (PFCAs) and the PFAS sorption increased with increasing perfluorocarbon chain length with 0.60 and 0.83 log K OC units per CF 2 moiety for C 3 -C 10 PFCAs and C 4 , C 6 , and C 8 PFSAs, respectively. The effects of cation treatment and SOM bulk net charge were evident for many PFASs with low to moderate sorption (C 5 -C 8 PFCAs and C 6 PFSA). However for the most strongly sorbing and most long-chained PFASs (C 9 -C 11 and C 13 PFCAs, C 8 PFSA and perfluorooctane sulfonamide (FOSA)), smaller effects of cations were seen, and instead sorption was more strongly related to the pH value. This suggests that the most long-chained PFASs, similar to other hydrophobic organic compounds, are preferentially sorbed to the highly condensed domains of the humin fraction, while shorter-chained PFASs are bound to a larger extent to humic and fulvic acid, where cation effects are significant. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Four Chemical Trends Will Shape the Next Decade's Directions in Perfluoroalkyl and Polyfluoroalkyl Substances Research.

Science.gov (United States)

Kotthoff, Matthias; Bücking, Mark

2018-01-01

Per- and polyfluoroalkyl substances (PFAS) represent a versatile group of ubiquitously occurring chemicals of increasing regulatory concern. The past years lead to an ever expanding portfolio of detected anthropogenic PFAS in numerous products encountered in daily life. Yet no clear picture of the full range of individual substance that comprise PFAS is available and this challenges analytical and engineering sciences. Authorities struggle to cope with uncertainties in managing risk of harm posed by PFAS. This is a result of an incomplete understanding of the range of compounds that they comprise in differing products. There are analytical uncertainties identifying PFAS and estimating the concentrations of the total PFAS load individual molecules remain unknown. There are four major trends from the chemical perspective that will shape PFAS research for the next decade. Mobility: A wide and dynamic distribution of short chain PFAS due to their high polarity, persistency and volatility.Substitution of regulated substances: The ban or restrictions of individual molecules will lead to a replacement with substitutes of similar concern.Increase in structural diversity of existing PFAS molecules: Introduction of e.g., hydrogens and chlorine atoms instead of fluorine, as well as branching and cross-linking lead to a high versatility of unknown target molecules.Unknown "Dark Matter": The amount, identity, formation pathways, and transformation dynamics of polymers and PFAS precursors are largely unknown. These directions require optimized analytical setups, especially multi-methods, and semi-specific tools to determine PFAS-sum parameters in any relevant matrix.

Imaging in Vivo Extracellular pH with a Single Paramagnetic Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Contrast Agent

Directory of Open Access Journals (Sweden)

Guanshu Liu

2012-01-01

Full Text Available The measurement of extracellular pH (pHe has potential utility for cancer diagnoses and for assessing the therapeutic effects of pH-dependent therapies. A single magnetic resonance imaging (MRI contrast agent that is detected through paramagnetic chemical exchange saturation transfer (PARACEST was designed to measure tumor pHe throughout the range of physiologic pH and with magnetic resonance saturation powers that are not harmful to a mouse model of cancer. The chemical characterization and modeling of the contrast agent Yb3+-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, 10-o-aminoanilide (Yb-DO3A-oAA suggested that the aryl amine of the agent forms an intramolecular hydrogen bond with a proximal carboxylate ligand, which was essential for generating a practical chemical exchange saturation transfer (CEST effect from an amine. A ratio of CEST effects from the aryl amine and amide was linearly correlated with pH throughout the physiologic pH range. The pH calibration was used to produce a parametric pH map of a subcutaneous flank tumor on a mouse model of MCF-7 mammary carcinoma. Although refinements in the in vivo CEST MRI methodology may improve the accuracy of pHe measurements, this study demonstrated that the PARACEST contrast agent can be used to generate parametric pH maps of in vivo tumors with saturation power levels that are not harmful to a mouse model of cancer.

Effect of Mineral and Humic Substances on Tailing Soil Properties and Nutrient Uptake by Pennisetum purpureum Schumach

Directory of Open Access Journals (Sweden)

Adhe Phoppy Wira Etika

2015-05-01

Full Text Available Tin mining produces a by-product sand tailing from soil leaching with characteristic low pH and total organic carbon, and can be reclaimed by providing a suitable ameliorant. When available in situ, ameliorant materials can be economically used as they are required in large amounts. Fortunately, Bangka Belitung has sample stock of such kaolinite-rich minerals that can be utilized for improving soil chemical properties. Extracted organic materials, such as humic substances, can also be utilized as they influence the complex soil reactions, and promote plant growth. Thus, this study aimed to assess the effects of mineral, humic materials and interaction of both material on soil chemical properties and nutrient uptake of Pennisetum purpureum Schumach. A completely randomized design with 2 factors and 3 replications each was employed. Factor 1 was mineral matter is 0; 420; 840; 1.260 Mg ha-1 while Factor 2 was humic material is 0; 0.46; 0.92; 1.38 kg C ha-1. Air-dried samples of tailing were applied with oil palm compost then mixed evenly with mineral and humic materials. Penissetum purpureum Schumach was planted after 4 weeks incubation, and maintained for another 4 weeks. The results demonstrated that the addition of mineral matter significantly increased soil organic carbon content, total N, exchangeable K, Fe, Mn and boosted nutrient - total Ca, Mg and Mn – uptake of the plant. But the application of humic material increased only soil organic carbon content. The interaction of both materials only lowered soil pH.

Nitrifying aerobic granular sludge fermentation for releases of carbon source and phosphorus: The role of fermentation pH.

Science.gov (United States)

Zou, Jinte; Pan, Jiyang; He, Hangtian; Wu, Shuyun; Xiao, Naidong; Ni, Yongjiong; Li, Jun

2018-07-01

The effect of fermentation pH (uncontrolled, 4 and 10) on the releases of carbon source and phosphorus from nitrifying aerobic granular sludge (N-AGS) was investigated. Meanwhile, metal ion concentration and microbial community characterization were explored during N-AGS fermentation. The results indicated that N-AGS fermentation at pH 10 significantly promoted the releases of soluble chemical oxygen demand (SCOD) and total volatile fatty acids (TVFAs). However, SCOD and TVFA released from N-AGS were inhibited at pH 4. Moreover, acidic condition promoted phosphorus release (mainly apatite) from N-AGS during anaerobic fermentation. Nevertheless, alkaline condition failed to increase phosphorus concentration due to the formation of chemical-phosphate precipitates. Compared with the previously reported flocculent sludge fermentation, N-AGS fermentation released more SCOD and TVFAs, possibly due to the greater extracellular polymeric substances content and some hydrolytic-acidogenic bacteria in N-AGS. Therefore, N-AGS alkaline fermentation facilitated the carbon source recovery, while N-AGS acidic fermentation benefited the phosphorus recovery. Copyright © 2018. Published by Elsevier Ltd.

Effect of pH on optic and structural characterization of chemical deposited AgI thin films

Energy Technology Data Exchange (ETDEWEB)

Tezel, Fatma Meydaneri [Department of Metallurgy and Materials Engineering, Karabük University (Turkey); Kariper, İshak Afşin [Department of Science Education, Faculty of Education, Erciyes University, Kayseri (Turkey)

2017-11-15

AgI thin films were grown on amorphous commercial glass substrates with chemical bath deposition (CBD) at different pH values (2, 3, 4, 5, 6), 6 hours deposition time and 60 °C. The structure of the nanocrystals was characterized by X-ray diffraction (XRD). The ratio of Ag{sup +} and I{sup -} ions changed the crystalline structures. The presence of the Ag{sup +} ions produces the γ-phase of AgI and excess of iodine concentration produces β-phase of AgI. The pH: 4 was like a transition pH for these phases. The number of crystallites per unit area has maximum value at pH: 5, as the structure is re-crystallization to hexagonal phase. Also, the thicknesses of produced thin films were decreased with increased pH values. Therefore, transmission, reflection, extinction coefficients and refractive index of the materials were affected by thicknesses, and calculated to be 32, 35, 3, 11, 9 (%) - 27, 25, 61, 45, 49 (%) - 0.036, 0.032, 0.067, 0.107, 0.075 and 3.21, 3.02, 5.16, 8.35, 5.70 in 550 nm at pH: 2-3-4-5-6 values, respectively. The exciton peaks of AgI were observed at between 320 and 420 nm. Surface properties were investigated by using scanning electron microscopy (SEM). (author)

Investigations with beagles about toxicity and radioprotective effect of the chemical radioprotection substance WR 2721

International Nuclear Information System (INIS)

Wagner, M.; Sedlmeier, H.; Wustrow, T.; Messerschmidt, O.

1980-01-01

The toxicity of the chemical radioprotection substance WR 2721 (S-2-(3-aminopropylamino)ethyl-thiophosphate) was examined in 25 beagles. The study showed that the toxicity of the substance increases as the dose gets higher. Between the doses 200 and 250 mg/kg of body weight, the increase of toxicity was significantly greater than could be expected on the basis of the dose difference. Until a dose of 200 mg/kg, the authors found no side effects which would have disturbed vital functions, but higher doses led to marked symptoms of intoxication. (orig.) [de

Safety evaluation of food contact paper and board using chemical tests and in vitro bioassays: role of known and unknown substances.

Science.gov (United States)

Honkalampi-Hämäläinen, U; Bradley, E L; Castle, L; Severin, I; Dahbi, L; Dahlman, O; Lhuguenot, J-C; Andersson, M A; Hakulinen, P; Hoornstra, D; Mäki-Paakkanen, J; Salkinoja-Salonen, M; Turco, L; Stammati, A; Zucco, F; Weber, A; von Wright, A

2010-03-01

In vitro toxicological tests have been proposed as an approach to complement the chemical safety assessment of food contact materials, particularly those with a complex or unknown chemical composition such as paper and board. Among the concerns raised regarding the applicability of in vitro tests are the effects of interference of the extractables on the outcome of the cytotoxicity and genotoxicity tests applied and the role of known compounds present in chemically complex materials, such as paper and board, either as constituents or contaminants. To answer these questions, a series of experiments were performed to assess the role of natural substances (wood extracts, resin acids), some additives (diisopropylnaphthalene, phthalates, acrylamide, fluorescent whitening agents) and contaminants (2,4-diaminotoluene, benzo[a]pyrene) in the toxicological profile of paper and board. These substances were individually tested or used to spike actual paper and board extracts. The toxic concentrations of diisopropylnaphthalenes and phthalates were compared with those actually detected in paper and board extracts showing conspicuous toxicity. According to the results of the spiking experiments, the extracts did not affect the toxicity of tested chemicals nor was there any significant metabolic interference in the cases where two compounds were used in tests involving xenobiotic metabolism by the target cells. While the identified substances apparently have a role in the cytotoxicity of some of the project samples, their presence does not explain the total toxicological profile of the extracts. In conclusion, in vitro toxicological testing can have a role in the safety assessment of chemically complex materials in detecting potentially harmful activities not predictable by chemical analysis alone.

Biosorption phenomena of chromium, copper, iron and zink by dispersed bacterial extracellular polymeric substance

International Nuclear Information System (INIS)

Zainus Salimin; Endang Nuraeni; Mirawaty

2015-01-01

Heavy metals removing is generally performed using chemical coagulant that generates the chemical pollutant, so it is necessary to replace it by another alternative material as the Extracellular Polymeric Substance (EPS) resulting from the extraction of bacteria. The EPS contains the negatively functional groups (RCOOH, ROPO 3 H, ROPO 3 Na, ROSO 3 H, ROSO 3 Na, etc) as the cation sorbent and the positively functional groups (ROH, RC(NH 2 )HCOOH, etc) as the anion sorbent. The EPS absorbs the ion pollutants, then EPS containing the loaded metals be settled by gravitation. The utilization of EPS for removing of chromium, copper, iron, and zink was performed for biosorption phenomena study. Two hundred mg of EPS is mixed with 300 ml of the liquid waste having the pH of 2,4 containing 3,06 ppm of chromium; 4,83 ppm of copper; 1,6 ppm of iron and 15,07 ppm of zink. The solution is then agitated on 150 rpm and the pH of 7. The separated water supernatant is then sampled every 2 hours for its analysis of metals content. The experiment is repeated again for the solution pH of 4 and 8. The results of experiment indicates that the EPS composition are 11% of polysaccharides, 77% of protein, and 11% of fat ,and EPS contains the chemical bounding of C-H, OH, NH, and C=O. Indicating that EPS contains RCOOH, ROH and (RC(NH 2 )HCOOH. The best condition for metals biosorption is pH 8, and on the 6 hours of process time, the metal concentration on the water supernatant for chromium, copper, iron and zinc are 0,99 ppm; 0,51 ppm; 0,17 ppm; and 4,61 ppm respectively. Its selectivities are Fe 3+ > Cr 3+ >Cu 2+ >Fe 2+ >Zn 2+ , on the 6 hours of process time the location of cations functional groups was filled by the cations of Cr 3+ ,Cu 2+ , dan Fe 2+ . The cation of Zn 2+ enters to that location on the end of period so on the 6 hours of process time its concentration of 4,61 ppm not conforms to its concentration of regulation value of 2 ppm. On the process time of 6 hours the removing

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. Organic substances and pharmaceuticals engineering. Petrochemistry and chemical processing of alternative feedstock

International Nuclear Information System (INIS)

Zakhodyaeva, Yu.A.; Belova, V.V.

2012-01-01

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 organic substances and pharmaceuticals engineering, petrochemistry and chemical processing of alternative feedstock. 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 [ru

NODC Standard Format Marine Toxic Substances and Pollutants (F144) chemical identification codes (NODC Accession 9200273)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival information package contains a listing of codes and chemical names that were used in NODC Standard Format Marine Toxic Substances and Pollutants (F144)...

Effect of pH on the chemical modification of quercetin and structurally related flavonoids characterized by optical (UV-visible and Raman) spectroscopy.

Science.gov (United States)

Jurasekova, Z; Domingo, C; Garcia-Ramos, J V; Sanchez-Cortes, S

2014-07-07

In this work we report the study of the chemical modifications undergone by flavonoids, especially by quercetin (QUC), under alkaline conditions by UV-visible absorption, Raman and surface-enhanced Raman scattering (SERS) spectroscopy, the study was performed in aqueous solution and also on Ag nanoparticles (AgNPs). Several processes are involved in the effect of alkaline pH both in solution and on AgNPs: autoxidation affecting mainly the C-ring of the molecule and giving rise to the molecular fragmentation leading to simpler molecular products, and/or the dimerization and further polymerization leading to species with a higher molecular weight. In addition, there exists a clear structure-instability correlation concerning mainly particular groups in the molecule: the C3-OH group in the C-ring, the catechol moiety in the B-ring and the C2=C3 bond also existing in the C-ring. QUC possesses all these groups and exhibits high instability in alkaline solution. The SERS spectra registered at different pH revealed a change in the dimerization protocol of QUC going from the A- and C-rings-like-condensation to B-ring-like-condensation. Increasing the knowledge of the chemical properties of these compounds and determining the structure-activity relationship under specific environmental factors allow us to improve their beneficial properties for health as well as the preservation of Cultural Heritage objects, for example, by preventing their degradation.

Oxidative stability of soybean oil in oleosomes as affected by pH and iron.

Science.gov (United States)

Kapchie, Virginie N; Yao, Linxing; Hauck, Catherine C; Wang, Tong; Murphy, Patricia A

2013-12-01

The oxidative stability of oil in soybean oleosomes, isolated using the Enzyme-Assisted Aqueous Extraction Process (EAEP), was evaluated. The effects of ferric chloride, at two concentration levels (100 and 500 μM), on lipid oxidation, was examined under pH 2 and 7. The peroxide value (PV) and thiobarbituric acid-reactive substance (TBARS) value of oil, in oleosome suspensions stored at 60 °C, were measured over a 12 day period. The presence of ferric chloride significantly (Poil in the isolated oleosome, as measured by the PV and TBARS. Greater lipid oxidation occurred under an acidic pH. In the pH 7 samples, the positively charged transition metals were strongly attracted to the negatively charged droplets. However, the low ζ-potential and the high creaming rate at this pH, may have limited the oxidation. Freezing, freeze-drying or heating of oleosomes have an insignificant impact on the oxidative stability of oil in isolated soybean oleosomes. Manufacturers should be cautious when adding oleosomes as ingredients in food systems containing transition metal ions. Published by Elsevier Ltd.

Environmental effects and potential hazards of chemical substances used in waste water purification; Umweltvertraeglichkeit und Gefaehrdungspotentiale von Abwasserbehandlungschemikalien

Energy Technology Data Exchange (ETDEWEB)

Schumann, H. [Umweltbundesamt, Berlin (Germany). Inst. fuer Wasser-, Boden- und Lufthygiene

1999-07-01

Waste water purification in sewage systems would be impossible without additions of chemical substances for coagulation, flocculation and neutralisation. However, these substances also pollute the purified waste water and the freshwater supplies. In addition, the non-reactive fraction of toxic substances originally contained in the waste water is discharged with the purified waste water and adds to the pollution of freshwater reservoirs. Detailed investigations are required for defining the state of the art in the use of chemical substances for waste water purification. [German] Um Schadstoffe aus dem Abwasser zu entfernen, werden in der Klaeranlage bestimmte Hilfsstoffe zugesetzt, ohne die eine Reinigung des Abwassers nicht in dieser Qualitaet moeglich waere und unverhaeltnismaessig teuer wuerde. Die Hilfsstoffe unterstuetzen den Reinigungsprozess durch Faellung, Flockung und Neutralisation. Durch den Einsatz dieser Chemikalien zur Behandlung von Abwaessern gelangen jedoch auch - Verunreinigungen durch die Nebenstoff-Matrix der eingesetzten Behandlungschemikalien in das behandelte Abwasser und in die Gewaesser und - durch ueberstoechiometrische Dosierung oder Additive tritt der nicht reagierende Teil toxischer Substanzen ebenfalls im behandelten Abwasserablauf und im Gewaesser auf. Detaillierte Untersuchungen erscheinen geboten, um auf dieser Grundlage den Stand der Technik beim Einsatz von Chemikalien zur Abwasserbehandlung zu formulieren. (orig./SR)

Four chemical trends will shape the next decade's directions in Perfluoroalkyl and Polyfluoroalkyl substances research

Science.gov (United States)

Kotthoff, Matthias; Bücking, Mark

2018-04-01

Per- and polyfluoroalkyl substances (PFAS) represent a versatile group of ubiquitously occurring chemicals of increasing regulatory concern. The past years lead to an ever expanding portfolio of detected anthropogenic PFAS in numerous products encountered in daily life. Yet no clear picture of the full range of individual substance that comprise PFAS is available and this challenges analytical and engineering sciences. Authorities struggle to cope with uncertainties in managing risk of harm posed by PFAS.This is a result of an incomplete understanding of the range of compounds that they comprise in differing products. There are analytical uncertainties identifying PFAS and estimating the concentrations of the total PFAS loadindividual molecules remain unknown. There are four major trends from the chemical perspective that will shape PFAS research for the next decade. 1.Mobility: A wide and dynamic distribution of short chain PFAS due to their high polarity, persistency and volatility. 2.Substitution of regulated substances: The ban or restrictions of individual molecules will lead to a replacement with substitutes of similar concern. 3.Increase in structural diversity of existing PFAS molecules: Introduction of e.g. hydrogens and chlorine atoms instead of fluorine, as well as branching and cross-linking lead to a high versatility of unknown target molecules. 4. Unknown “Dark Matter”: The amount, identity, formation pathways, and transformation dynamics of polymers and PFAS precursors are largely unknown. These directions require optimized analytical setups, especially multi-methods, and semi-specific tools to determine PFAS-sum parameters in any relevant matrix.

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)

Zakhodyaeva, Yu.A.; Belova, V.V.

2012-01-01

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 [ru

Effect of time and pH on physical-chemical properties of orthodontic brackets and wires.

Science.gov (United States)

Dos Santos, Aretha Aliny Ramos; Pithon, Matheus Melo; Carlo, Fabíola Galbiatti Carvalho; Carlo, Hugo Lemes; de Lima, Bruno Alessandro Silva Guedes; Dos Passos, Tibério Andrade; Lacerda-Santos, Rogério

2015-03-01

To test the hypothesis that treatment time, debris/biofilm, and oral pH have an influence on the physical-chemical properties of orthodontic brackets and arch wires. One hundred twenty metal brackets were evaluated. They were divided into four groups (n  =  30) according to treatment time: group C (control) and groups T12, T24, and T36 (brackets recovered after 12, 24, and 36 months of treatment, respectively). Rectangular stainless-steel arch wires that remained in the oral cavity for 12 to 24 months were also analyzed. Dimensional stability, surface morphology, composition of brackets, resistance to sliding of the bracket-wire set, surface roughness of wires, and oral pH were analyzed. One-way analysis of variance, followed by a Tukey multiple comparisons test, was used for statistical analysis (P bracket slots were shown to have more influence on the degradation process and frictional force of these devices than did oral pH.

[Formation mechanism and chemical safety of nonintentional chemical substances present in chlorinated drinking water and wastewater].

Science.gov (United States)

Onodera, Sukeo

2010-09-01

This paper reviews the formation mechanism and chemical safety of nonintentional chemical substances (NICS) present in chlorine-treated water containing organic contaminants. Undesirable compounds, i.e., NICS, may be formed under certain conditions when chlorine reacts with organic matter. The rate and extent of chlorine consumption with organics are strongly dependent on their chemical structures, particularly whether double bonds or sulfur and nitrogen atoms occur in the molecules. Organothiophosphorus pesticides (P=S type) are easily oxidized to their phosphorus compounds (P=O type) in chlorinated water containing HOCl as little as 0.5 mg/l, resulting in an increase in cholinesterase-inhibitory activity. Chlorination of phenols in water also produces a series of highly chlorinated compounds, including chlorophenols, chloroquinones, chlorinated carboxylic acids, and polychlorinated phenoxyphenols (PCPPs). In some of these chloroquinones, 2,6-dichloroalkylsemiquinones exhibit a strong mutagenic response as do positive controls used in the Ames test. 2-phenoxyphenols in these PCPPs are particularly interesting, as they are present in the chlorine-treated phenol solution and they are also precursors (predioxins) of the highly toxic chlorinated dioxins. Polynuclear aromatic hydrocarbons (PAHs) were found to undergo chemical changes due to hypochlorite reactions to give chloro-substituted PAHs, oxygenated (quinones) and hydroxylated (phenols) compounds, but they exhibit a lower mutagenic response. In addition, field work was performed in river water and drinking water to obtain information on chemical distribution and their safety, and the results are compared with those obtained in the model chlorination experiments.

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.

Effects of pH and microbial composition on odour in food waste composting

Science.gov (United States)

Sundberg, Cecilia; Yu, Dan; Franke-Whittle, Ingrid; Kauppi, Sari; Smårs, Sven; Insam, Heribert; Romantschuk, Martin; Jönsson, Håkan

2013-01-01

A major problem for composting plants is odour emission. Slow decomposition during prolonged low-pH conditions is a frequent process problem in food waste composting. The aim was to investigate correlations between low pH, odour and microbial composition during food waste composting. Samples from laboratory composting experiments and two large scale composting plants were analysed for odour by olfactometry, as well as physico-chemical and microbial composition. There was large variation in odour, and samples clustered in two groups, one with low odour and high pH (above 6.5), the other with high odour and low pH (below 6.0). The low-odour samples were significantly drier, had lower nitrate and TVOC concentrations and no detectable organic acids. Samples of both groups were dominated by Bacillales or Actinobacteria, organisms which are often indicative of well-functioning composting processes, but the high-odour group DNA sequences were similar to those of anaerobic or facultatively anaerobic species, not to typical thermophilic composting species. High-odour samples also contained Lactobacteria and Clostridia, known to produce odorous substances. A proposed odour reduction strategy is to rapidly overcome the low pH phase, through high initial aeration rates and the use of additives such as recycled compost. PMID:23122203

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.

pH measurements of FET-based (bio)chemical sensors using portable measurement system.

Science.gov (United States)

Voitsekhivska, T; Zorgiebel, F; Suthau, E; Wolter, K-J; Bock, K; Cuniberti, G

2015-01-01

In this study we demonstrate the sensing capabilities of a portable multiplex measurement system for FET-based (bio)chemical sensors with an integrated microfluidic interface. We therefore conducted pH measurements with Silicon Nanoribbon FET-based Sensors using different measurement procedures that are suitable for various applications. We have shown multiplexed measurements in aqueous medium for three different modes that are mutually specialized in fast data acquisition (constant drain current), calibration-less sensing (constant gate voltage) and in providing full information content (sweeping mode). Our system therefore allows surface charge sensing for a wide range of applications and is easily adaptable for multiplexed sensing with novel FET-based (bio)chemical sensors.

Toxin production in food as influenced by pH, thermal treatment and ...

African Journals Online (AJOL)

Toxin production in food as influenced by pH, thermal treatment and chemical ... carrot, spinach, pepper, tomato, onion and cooked food samples (rice, yam, beans, ... on the growth rate and toxin elaboration of E. coli, K. aerogenes, C. freundii, ...

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

DETERMINATION OF RELATED IMPURITIES IN THE ANILOCAINE SUBSTANCE BY HPLC METHOD

Directory of Open Access Journals (Sweden)

D. R. Sabirzyanov

2017-01-01

Full Text Available Anilocaine is a local anesthetic from the group of substituted amides, synthesized in the Perm State Pharmaceutical Academy. Anilocaine shows high surface anesthetic, infiltration and conduction anesthesia and shows the high efficiency in the various fields of medical practice. The quality of produced medicines depends on the quality of pharmaceutical substances. The purity is one of the most important parameters of the quality of pharmaceutical substances. The aim of this work was the development and validation of methods for identification of specific impurities in the substance of anilocaine by high-performance liquid chromatography (HPLC. Materials and methods. Studies were performed on liquid chromatography LC-20 Prominence (Shimadzu, Japan equipped with a diode-array detector (SPD-M20A. Chromatographic column was Zorbax SB-C18 (4.6 mm × 250 mm, 5 μm. Validation assessment of the developed method conducted in accordance with the requirements of FP XIII and international requirementsICH (International Conference on Harmonization. Results and discussion. An experiment on the selection of the conditions of chromatographically showed that optimal separation of anilocaine and possible impurities (identified and unidentified by the method of reversed-phase HPLC is observed in isocratic mode, using an eluent based on phosphate buffer pH 3 and acetonitrile. The flow rate of mobile phase is 1 ml/min; wavelength detection is 210 nm. Time check chromatogram is 20 minutes. Conclusion. The method for the quantitative determination of impurities in the substance of anilocaine by high-performance liquid chromatography was developed as the result of the research. The validation procedure of the analytical methods established its specificity, linearity, precision and accuracy. This method is included in the project monograph on substance of anilocaine.

Initiated chemical vapor deposition of pH responsive poly(2-diisopropylamino)ethyl methacrylate thin films

Energy Technology Data Exchange (ETDEWEB)

Karaman, Mustafa, E-mail: karamanm@selcuk.edu.tr [Department of Chemical Engineering, Selcuk University (Turkey); Advanced Technology Research and Application Center, Selcuk University (Turkey); Cabuk, Nihat [Department of Chemical Engineering, Selcuk University (Turkey)

2012-08-31

Poly(2-(diisopropylamino)ethyl methacrylate) (PDPAEMA) thin films were deposited on low temperature substrates by initiated chemical vapor deposition (iCVD) method using tertbutyl peroxide as an initiator. Very high deposition rates up to 38 nm/min were observed at low filament temperatures due to the use of the initiator. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy show the formation of PDPAEMA films with high retention of tertiary amine functionality which is responsible for pH induced changes in the wetting behavior of the surfaces. As-deposited PDPAEMA thin films on flat Si surface showed a reversible switching of water contact angle values between 87 Degree-Sign and 28 Degree-Sign ; after successive treatments of high and low pH water solutions, respectively. Conformal and non-damaging nature of iCVD allowed to functionalize fragile and rough electrospun poly(methyl methacrylate) fiber mat surfaces by PDPAEMA, which creates a surface with a switching behavior between superhydrophobic and approaching superhydrophilic with contact angle values of 155 {+-} 3 Degree-Sign and 22 {+-} 5 Degree-Sign , respectively. - Highlights: Black-Right-Pointing-Pointer Poly(2-diisopropylaminoethyl methacrylate) thin films were deposited by a dry process. Black-Right-Pointing-Pointer Initiated chemical vapor deposition can produce thin films on fragile substrates. Black-Right-Pointing-Pointer We report a reversible pH-induced transition from hydrophilic to super-hydrophobic.

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...

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.

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

Directory of Open Access Journals (Sweden)

E.O. Ajayi

2016-09-01

Full Text Available 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. Keywords: Essential oil, Cymbopogon citratus, pH Extraction medium

Patterns of development of unspecific reaction of cells and modification of chemical protection

International Nuclear Information System (INIS)

Veksler, A.M.; Korystov, Yu.N.; Kublik, L.N.; Ehjdus, L.Kh.

1980-01-01

A study was made of a correlation between radioprotective efficiency of different chemical agents (weak electrolytes) and conditions of treatment. It was demonstrated that the pattern of changes in the protection efficiency, with modification thereof, is similar to that of the development of unspecific reaction and determined by the intracellular concentration of the chemical agents, which, in turn, is function of physicochemical parameters of the substance and pH gradient between cell and medium. With similar intracellular concentration, caffeine-benzoate, thioglicolic acid and caffeine proved to be equally effective, while the protective effect of cysteamine was appreciably higher

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

... expectation is that the TSCA proposal would focus on providing aggregate pictures of the chemical substances... focused attention on hydraulic fracturing due to specific concerns raised about this practice, and most of...

Notification of the commission on the eco-toxicity of chemical substances; Avis de la commission d'evaluation de l'ecotoxicite des substances chimiques

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

The french commission on the evaluation of the chemical substances eco-toxicity, published recommendations concerning the use of additives for the automotive fuels, for the cooling circuit of electric power plants and for gases against fire. The risks for the public health are analysed and safety precautions are asked. (A.L.B.)

The PhD by Publication

Directory of Open Access Journals (Sweden)

Susi Peacock

2017-07-01

Full Text Available Aim/Purpose: The purpose of this work is to develop more nuanced understandings of the PhD by publication, particularly raising awareness of the retrospective PhD by publication. The article aims to contribute to contemporary debates about the differing pathways to the attainment of doctoral study completion and the artifacts submitted for that purpose. It also seeks to support prospective graduate students and supervisors who are embarking upon alternative routes to doctoral accreditation. Background: The PhD is considered the pinnacle of academic study – highly cherished, and replete with deeply held beliefs. In response to changes in job markets, developments in the disciplines, and more varied student cohorts, diverse pathways to completion of this award have emerged, such as the PhD by publication (PhDP. A PhDP may either be prospective or retrospective. For the former, publications are planned and created with their contributions to the PhDP in mind. The retrospective PhD is assembled after some, or most, of the publications have been completed. The artifact submitted for examination in this case consists of a series of peer-reviewed academic papers, books, chapters, or equivalents that have been published or accepted for publication, accompanied by an over-arching narrative. The retrospective route is particularly attractive for professionals who are research-active but lack formal academic accreditation at the highest level. Methodology: This article calls upon a literature review pertaining to the award of PhDP combined with the work of authors who offer their personal experiences of the award. The author also refers to her candidature as a Scottish doctoral student whilst studying for the award of PhD by publication. Contribution: This work raises awareness of the PhDP as a credible and comparable pathway for graduate students. The article focuses upon the retrospective PhDP which, as with all routes to doctoral accreditation, has

Complexation of Eu(III), Th(IV) and U(VI) by humic substances

International Nuclear Information System (INIS)

Moulin, V.; Reiller, P.; Dautel, C.; Plancque, G.; Laszak, I.; Moulin, C.

1999-01-01

Complexation of actinides by humic substances has been studied by different techniques depending on the actinide and its oxidation state. For trivalent actinide (using a rare earth element, Eu as an analogue of trivalent actinide), Time-Resolved Laser-Induced Fluorescence (TRLIF) has been retained as a method for direction speciation at low level. By varying pH and physicochemical conditions (absence of carbonate ions) and at fixed ionic strength, it is possible together to identify spectrally and temporally, all the hydroxo and carbonato complexes. This approach has also been retained for U(VI) as a model of hexavalent actinide, for which hydroxo complexes have been characterized by TRLIF (the simple carbonato complexes are not fluorescent). In the case of U(VI), titrations hy humic acids of U(VI) solutions at various pH have allowed to characterize organic complexes formed with U(VI): single complexes (UO 2 HA) and mixed complexes (UO 2 (OH) 3 HA). The impact on U(VI) speciation has then been identified. In the case of Th(IV) as a model of tetravalent actinides, a competitive method has been used to obtain data on the Th-HA system by studying the ternary system silica colloid/HA/Th at constant pH (Schubert method). Apparent interaction constants have been calculated depending on Th hydrolysis constants used. A study of the system Th/HA/silica has a function of pH and for different HA concentrations has shown the strong complexing character of humic acids towards Th in the pH range 4-9. (orig.)

The high pH chemical and radiation compatibility of various liner materials

International Nuclear Information System (INIS)

Whyatt, G.A.; Farnsworth, R.K.

1990-01-01

This paper reports on a flexible membrane liner that 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 would be different that 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

The high pH chemical and radiation compatibility of various liner materials

International Nuclear Information System (INIS)

Whyatt, G.; Farnsworth, R.

1990-01-01

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

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.

Detection of chemical substances in water using an oxide nanowire transistor covered with a hydrophobic nanoparticle thin film as a liquid-vapour separation filter

Directory of Open Access Journals (Sweden)

Taekyung Lim

2016-08-01

Full Text Available We have developed a method to detect the presence of small amounts of chemical substances in water, using a Al2O3 nanoparticle thin film covered with phosphonic acid (HDF-PA self-assembled monolayer. The HDF-PA self-assembled Al2O3 nanoparticle thin film acts as a liquid-vapour separation filter, allowing the passage of chemical vapour while blocking liquids. Prevention of the liquid from contacting the SnO2 nanowire and source-drain electrodes is required in order to avoid abnormal operation. Using this characteristic, the concentration of chemical substances in water could be evaluated by measuring the current changes in the SnO2 nanowire transistor covered with the HDF-PA self-assembled Al2O3 nanoparticle thin film.

History of EPI Suite™ and future perspectives on chemical property estimation in US Toxic Substances Control Act new chemical risk assessments.

Science.gov (United States)

Card, Marcella L; Gomez-Alvarez, Vicente; Lee, Wen-Hsiung; Lynch, David G; Orentas, Nerija S; Lee, Mari Titcombe; Wong, Edmund M; Boethling, Robert S

2017-03-22

Chemical property estimation is a key component in many industrial, academic, and regulatory activities, including in the risk assessment associated with the approximately 1000 new chemical pre-manufacture notices the United States Environmental Protection Agency (US EPA) receives annually. The US EPA evaluates fate, exposure and toxicity under the 1976 Toxic Substances Control Act (amended by the 2016 Frank R. Lautenberg Chemical Safety for the 21 st Century Act), which does not require test data with new chemical applications. Though the submission of data is not required, the US EPA has, over the past 40 years, occasionally received chemical-specific data with pre-manufacture notices. The US EPA has been actively using this and publicly available data to develop and refine predictive computerized models, most of which are housed in EPI Suite™, to estimate chemical properties used in the risk assessment of new chemicals. The US EPA develops and uses models based on (quantitative) structure-activity relationships ([Q]SARs) to estimate critical parameters. As in any evolving field, (Q)SARs have experienced successes, suffered failures, and responded to emerging trends. Correlations of a chemical structure with its properties or biological activity were first demonstrated in the late 19 th century and today have been encapsulated in a myriad of quantitative and qualitative SARs. The development and proliferation of the personal computer in the late 20 th century gave rise to a quickly increasing number of property estimation models, and continually improved computing power and connectivity among researchers via the internet are enabling the development of increasingly complex models.

Estimating the human exposure to chemical substances and radiation. Definition report

International Nuclear Information System (INIS)

Vermeire, T.G.; Van Veen, M.P.

1995-06-01

This report aims at boosting the human exposure assessment activities of the RIVM with regard to chemical substances and radiation. It is the result of thorough discussions with RIVM-experts. The report starts with an overview of past developments in the area of human exposure assessment at the RIVM and continues describing recent projects. Major developments outside the Institute are also discussed. An attempt is made to harmonize definitions which are relevant for exposure assessment, i.e. definitions on exposure, intake, uptake and dose. Important gaps in the human exposure assessment work at the RIVM are identified, leading to proposals for future work. 2 figs., 31 refs., 3 appendices

Adsorption of a reactive dye on chemically modified activated carbons--influence of pH.

Science.gov (United States)

Orfão, J J M; Silva, A I M; Pereira, J C V; Barata, S A; Fonseca, I M; Faria, P C C; Pereira, M F R

2006-04-15

The surface chemistry of a commercial activated carbon with a slightly basic nature was modified by appropriate treatments in order to obtain two additional samples, respectively with acidic and basic properties, without changing its textural parameters significantly. Different techniques (N2 adsorption at 77 K, temperature programmed desorption, and determination of acidity, basicity, and pH at the point of zero charge) were used to characterize the adsorbents. Kinetic and equilibrium adsorption data of a selected textile reactive dye (Rifafix Red 3BN, C.I. reactive red 241) on the mentioned materials were obtained at the pH values of 2, 7, and 12. The kinetic curves are fitted using the second-order model. The respective rate constants seem to diminish progressively with the initial concentration for the more diluted solutions tested, reaching a constant value at higher concentrations, which depends on the experimental system under consideration (adsorbent and pH). In general, the Langmuir model provides the best fit for the equilibrium data. The different uptakes obtained are discussed in relation to the surface chemical properties of the adsorbents. It is shown that the adsorption of the reactive (anionic) dye on the basic sample (prepared by thermal treatment under H2 flow at 700 degrees C) is favored. This conclusion is explained on the basis of the dispersive and electrostatic interactions involved. Moreover, it is also shown that the optimal adsorption condition for all the activated carbons tested corresponds to solution pH values not higher than the pH(pzc) of the adsorbents, which may be interpreted by taking into account the electrostatic forces present.

New York hazardous substances emergency events surveillance: learning from hazardous substances releases to improve safety

International Nuclear Information System (INIS)

Welles, Wanda Lizak; Wilburn, Rebecca E.; Ehrlich, Jenny K.; Floridia, Christina M.

2004-01-01

Since 1993, the New York State Department of Health, funded by the Agency for Toxic Substances and Disease Registry, has collected data about non-petroleum hazardous substances releases through the Hazardous Substances Emergency Events Surveillance (NYHSEES) project. This study investigates risk factors for hazardous substances releases that may result in public health consequences such as injury or reported health effects. The 6428 qualifying events that occurred during the 10-year-period of 1993-2002 involved 8838 hazardous substances, 842 evacuations, more than 75,419 people evacuated, and more than 3120 people decontaminated. These events occurred both at fixed facilities (79%) and during transport (21%). The causative factors most frequently contributing to reported events were equipment failure (39%) and human error (33%). Five of the 10 chemicals most frequently associated with injuries were also among the 10 chemicals most frequently involved in reported events: sulfuric acid, hydrochloric acid, ammonia, sodium hypochlorite, and carbon monoxide. The chemical categories most frequently associated with events, and with events with adverse health effects were volatile organic compounds (VOCs) and solvents, and acids. Events with releases of hazardous substances were associated with injuries to 3089 people including employees (37%), responders (12%), the general public (29%) and students (22%). The most frequently reported adverse health effects were respiratory irritation, headache, and nausea or vomiting. Most of the injured were transported to the hospital, treated, and released (55%) or treated at the scene (29%). These data have been used for emergency response training, planning, and prevention activities to reduce morbidity and mortality from future events

Infectious pancreatic necrosis virus in fish by-products is inactivated with inorganic acid (pH 1) and base (pH 12).

Science.gov (United States)

Myrmel, M; Modahl, I; Nygaard, H; Lie, K M

2014-04-01

The aquaculture industry needs a simple, inexpensive and safe method for the treatment of fish waste without heat. Microbial inactivation by inorganic acid (HCl) or base (KOH) was determined using infectious pancreatic necrosis virus (IPNV) as a model organism for fish pathogens. Salmonella and spores of Clostridium perfringens were general hygiene indicators in supplementary examinations. IPNV, which is considered to be among the most chemical- and heat-resistant fish pathogens, was reduced by more than 3 log in 4 h at pH 1.0 and pH 12.0. Salmonella was rapidly inactivated by the same treatment, whereas spores of C. perfringens were hardly affected. The results indicate that low and high pH treatment could be particularly suitable for fish waste destined for biogas production. pH treatment at aquaculture production sites could reduce the spread of fish pathogens during storage and transportation without disturbing the anaerobic digestion process. The treatment could also be an alternative to the current energy-intensive steam pressure sterilization of fish waste to be used by the bioenergy, fertilizer and soil improver industries. © 2013 John Wiley & Sons Ltd.

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.

Behavior of chemicals in the seawater column by shadowscopy

Science.gov (United States)

Fuhrer, Mélanie; Aprin, Laurent; Le Floch, Stéphane; Slangen, Pierre; Dusserre, Gilles

2012-10-01

Ninety percent of the Global Movement of Goods transit by ship. The transportation of HNS (Hazardous and Noxious Substances) in bulk highly increases with the tanker traffic. The huge volume capacities induce a major risk of accident involving chemicals. Among the latest accidents, many have led to vessels sinking (Ievoli Sun, 2000 - ECE, 2006). In case of floating substances, liquid release in depth entails an ascending two phase flow. The visualization of that flow is complex. Indeed, liquid chemicals have mostly a refractive index close to water, causing difficulties for the assessment of the two phase medium behavior. Several physics aspects are points of interest: droplets characterization (shape evolution and velocity), dissolution kinetics and hydrodynamic vortices. Previous works, presented in the 2010 Speckle conference in Brazil, employed Dynamic Speckle Interferometry to study Methyl Ethyl Ketone (MEK) dissolution in a 15 cm high and 1 cm thick water column. This paper deals with experiments achieved with the Cedre Experimental Column (CEC - 5 m high and 0.8 m in diameter). As the water thickness has been increased, Dynamic Speckle Interferometry results are improved by shadowscopic measurements. A laser diode is used to generate parallel light while high speed imaging records the products rising. Two measurements systems are placed at the bottom and the top of the CEC. The chemical class of pollutant like floaters, dissolvers (plume, trails or droplets) has been then identified. Physics of the two phase flow is presented and shows up the dependence on chemicals properties such as interfacial tension, viscosity and density. Furthermore, parallel light propagation through this disturbed medium has revealed trailing edges vortices for some substances (e.g. butanol) presenting low refractive index changes.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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.

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

International Nuclear Information System (INIS)

Ketcheson, K.; Shrives, J.

2005-01-01

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

pH dependent green synthesis of gold nanoparticles by completely C6-carboxylated curdlan under high temperature and various pH conditions.

Science.gov (United States)

Qiu, Wen-Yi; Wang, Kai; Wang, Yao-Yao; Ding, Zhi-Chao; Wu, Li-Xia; Cai, Wu-Dan; Yan, Jing-Kun

2018-01-01

A C6-carboxylated curdlan (C6-Cc) obtained from 4-acetamido-TEMPO-mediated oxidation of curdlan was used both as a reducing and stabilizing agent for green synthesis of pH-responsive AuNPs, which was carried out by controlling the pH of the C6-Cc solution at a high temperature (100°C). C6-Cc presented a semi-flexible random coil chain in the aqueous medium at pH 5.5 and became more expanded and rigid in alkaline conditions (pH 7.1-12.0), though the primary chemical structure of C6-Cc was virtually unchanged with the pH variation. The AuNPs prepared with C6-Cc at various pHs were characterized by various instrumental measurements. The shapes and sizes of AuNPs were found to be strongly dependent on the pH of the C6-Cc solution. The C6-Cc-decorated AuNPs exhibited a more well-dispersed spherical morphology with smaller particle sizes under alkaline conditions (pH 7.1-12.0). Through this study, a facile, simple, and green method has been demonstrated for preparation of stimuli-sensitive AuNPs using biocompatible polyanionic polysaccharides. Copyright © 2017 Elsevier B.V. All rights reserved.

Integrating chemical imaging of cationic trace metal solutes and pH into a single hydrogel layer

Energy Technology Data Exchange (ETDEWEB)

Hoefer, Christoph [Department of Forest and Soil Sciences, Institute of Soil Research, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, A-3430 Tulln (Austria); Santner, Jakob, E-mail: jakob.santner@boku.ac.at [Department of Forest and Soil Sciences, Institute of Soil Research, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, A-3430 Tulln (Austria); Department of Crop Sciences, Division of Agronomy, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Borisov, Sergey M. [Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010, Graz (Austria); Wenzel, Walter W.; Puschenreiter, Markus [Department of Forest and Soil Sciences, Institute of Soil Research, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, A-3430 Tulln (Austria)

2017-01-15

Gel-based, two-dimensional (2D) chemical imaging techniques are versatile methods for investigating biogeochemically active environments at high spatial resolution (sub-mm). State-of-the-art solute imaging techniques, such as diffusive gradients in thin films (DGT) and planar optodes (PO), employ passive solute sampling or sensing. Combining these methods will provide powerful tools for studying the biogeochemistry of biological niches in soils and sediments. In this study we aimed at developing a combined single-layer gel for direct pH imaging using PO and sampling of anionic and cationic solutes by DGT, with subsequent analysis of the bound solutes by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We tested three ultra-thin (<100 μm) polyurethane-based gels, incorporating anion and cation binding materials and the fluorescent pH indicator DCIFODA (2′,7′-dichloro-5(6)-N-octadecyl-carboxamidofluorescein). Results showed that PO-based pH sensing using DCIFODA was impossible in the presence of the anion binding materials due to interferences with DCIFODA protonation. One gel, containing only a cation binding material and DCIFODA, was fully characterized and showed similar performance characteristics as comparable DGT-only gels (applicable pH range: pH 5–8, applicable ionic strength range: 1–20 mmol L{sup -1}, cation binding capacity ∼24 μg cm{sup −2}). The dynamic range for PO-based pH mapping was between pH 5.5 and 7.5 with t{sub 90} response time of ∼60 min. In a case study we demonstrated the gel's suitability for multi-analyte solute imaging and mapped pH gradients and concurrent metal solubility patterns in the rhizosphere of Salix smithiana. pH decreases in the rooted soil were co-localized with elevated solute fluxes of Al{sup 3+}, Co{sup 2+}, Cu{sup 2+}, Fe, Mn{sup 2+}, Ni{sup 2+} and Pb{sup 2+}, indicating pH-induced metal solubilisation. - Highlights: • Diffusive gradients in thin films (DGT) and planar

Integrating chemical imaging of cationic trace metal solutes and pH into a single hydrogel layer

International Nuclear Information System (INIS)

Hoefer, Christoph; Santner, Jakob; Borisov, Sergey M.; Wenzel, Walter W.; Puschenreiter, Markus

2017-01-01

Gel-based, two-dimensional (2D) chemical imaging techniques are versatile methods for investigating biogeochemically active environments at high spatial resolution (sub-mm). State-of-the-art solute imaging techniques, such as diffusive gradients in thin films (DGT) and planar optodes (PO), employ passive solute sampling or sensing. Combining these methods will provide powerful tools for studying the biogeochemistry of biological niches in soils and sediments. In this study we aimed at developing a combined single-layer gel for direct pH imaging using PO and sampling of anionic and cationic solutes by DGT, with subsequent analysis of the bound solutes by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We tested three ultra-thin (<100 μm) polyurethane-based gels, incorporating anion and cation binding materials and the fluorescent pH indicator DCIFODA (2′,7′-dichloro-5(6)-N-octadecyl-carboxamidofluorescein). Results showed that PO-based pH sensing using DCIFODA was impossible in the presence of the anion binding materials due to interferences with DCIFODA protonation. One gel, containing only a cation binding material and DCIFODA, was fully characterized and showed similar performance characteristics as comparable DGT-only gels (applicable pH range: pH 5–8, applicable ionic strength range: 1–20 mmol L"-"1, cation binding capacity ∼24 μg cm"−"2). The dynamic range for PO-based pH mapping was between pH 5.5 and 7.5 with t_9_0 response time of ∼60 min. In a case study we demonstrated the gel's suitability for multi-analyte solute imaging and mapped pH gradients and concurrent metal solubility patterns in the rhizosphere of Salix smithiana. pH decreases in the rooted soil were co-localized with elevated solute fluxes of Al"3"+, Co"2"+, Cu"2"+, Fe, Mn"2"+, Ni"2"+ and Pb"2"+, indicating pH-induced metal solubilisation. - Highlights: • Diffusive gradients in thin films (DGT) and planar optode (PO) imaging is combined. • A

Fixation and transport of uranium by humic substances (1962)

International Nuclear Information System (INIS)

Martin, J.

1962-03-01

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) [fr

Waste paper for recycling: Overview and identification of potentially critical substances.

Science.gov (United States)

Pivnenko, Kostyantyn; Eriksson, Eva; Astrup, Thomas F

2015-11-01

Paper product manufacturing involves a variety of chemicals used either directly in paper and pulp production or in the conversion processes (i.e. printing, gluing) that follow. Due to economic and environmental initiatives, paper recycling rates continue to rise. In Europe, recycling has increased by nearly 20% within the last decade or so, reaching a level of almost 72% in 2012. With increasing recycling rates, lower quality paper fractions may be included. This may potentially lead to accumulation or un-intended spreading of chemical substances contained in paper, e.g. by introducing chemicals contained in waste paper into the recycling loop. This study provides an overview of chemicals potentially present in paper and applies a sequential hazard screening procedure based on the intrinsic hazard, physical-chemical and biodegradability characteristics of the substances. Based on the results, 51 substances were identified as potentially critical (selected mineral oils, phthalates, phenols, parabens, as well as other groups of chemicals) in relation to paper recycling. It is recommended that these substances receive more attention in waste paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

PETRORISK: a risk assessment framework for petroleum substances.

Science.gov (United States)

Redman, Aaron D; Parkerton, Thomas F; Comber, Mike H I; Paumen, Miriam Leon; Eadsforth, Charles V; Dmytrasz, Bhodan; King, Duncan; Warren, Christopher S; den Haan, Klaas; Djemel, Nadia

2014-07-01

PETRORISK is a modeling framework used to evaluate environmental risk of petroleum substances and human exposure through these routes due to emissions under typical use conditions as required by the European regulation for the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH). Petroleum substances are often complex substances comprised of hundreds to thousands of individual hydrocarbons. The physicochemical, fate, and effects properties of the individual constituents within a petroleum substance can vary over several orders of magnitude, complicating risk assessment. PETRORISK combines the risk assessment strategies used on single chemicals with the hydrocarbon block approach to model complex substances. Blocks are usually defined by available analytical characterization data on substances that are expressed in terms of mass fractions for different structural chemical classes that are specified as a function of C number or boiling point range. The physicochemical and degradation properties of the blocks are determined by the properties of representative constituents in that block. Emissions and predicted exposure concentrations (PEC) are then modeled using mass-weighted individual representative constituents. Overall risk for various environmental compartments at the regional and local level is evaluated by comparing the PECs for individual representative constituents to corresponding predicted no-effect concentrations (PNEC) derived using the Target Lipid Model. Risks to human health are evaluated using the overall predicted human dose resulting from multimedia environmental exposure to a substance-specific derived no-effect level (DNEL). A case study is provided to illustrate how this modeling approach has been applied to assess the risks of kerosene manufacture and use as a fuel. © 2014 SETAC.

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. Copyright © 2010 Elsevier Ltd. All rights reserved.

High acidity tolerance in lichens with fumarprotocetraric, perlatolic or thamnolic acids is correlated with low pKa1 values of these lichen substances.

Science.gov (United States)

Hauck, Markus; Jürgens, Sascha-René; Huneck, Siegfried; Leuschner, Christoph

2009-10-01

The depsidone fumarprotocetraric acid as well as the depsides perlatolic and thamnolic acids are lichen secondary metabolites. Their first dissociation constants (pK(a1)) in methanol were determined to be 2.7 for perlatolic acid and 2.8 for fumarprotocetraric and thamnolic acids by UV spectroscopy. Lower pK(a1) values are, so far, not known from lichen substances. Several lichens producing at least one of these compounds are known for their outstanding tolerance to acidic air pollution. This is demonstrated by evaluating published pH preferences for central European lichens. The low pK(a1) values suggest that strong dissociation of the studied lichen substances is a prerequisite for the occurrence of lichens with these compounds on very acidic substrata, as protonated lichen substances of different chemical groups, but not their conjugated bases, are known to shuttle protons into the cytoplasm and thereby apparently damage lichens.

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. Copyright © 2013 Elsevier GmbH. All rights reserved.

[Immunotoxicity and environmental substances].

Science.gov (United States)

Teshima, Reiko

2014-01-01

A well functioning immune system is essential in maintaining integrity of the organism, and malfunction may have severe health consequences. Environmental substances may pose direct toxicity to components of the immune system, often leading to immunosuppression and resulting reduced resistance to infections and tumors. Alternatively, such substances may be recognized by the immune system in a specific fashion, which may result in allergy and autoimmunity. A proper risk assessment of environmental substances in terms of immunotoxicity is necessary. In this manuscript, I reviewed recent three topics about immunotoxicity: (1) IPCS/WHO Guidance for immunotoxicity risk assessment for chemicals, (2) Intestinal immunotoxicity, and (3) Epicutaneous sensitization of food proteins.

Precipitation and ultimate pH effect on chemical and gelation properties of protein prepared by isoelectric solubilization/precipitation process from pale, soft, exudative (PSE)-like chicken breast meat1.

Science.gov (United States)

Zhao, X; Xing, T; Chen, X; Han, M-Y; Li, X; Xu, X-L; Zhou, G-H

2017-05-01

Pale, soft, exudative (PSE)-like chicken breast is considered deteriorated raw material in the poultry meat industry that has inferior processing ability. The chemical and gelation properties of PSE-like chicken breast meat paste were studied. These pastes were prepared by the pH adjustment method and protein isolation using the isoelectric solubilization/precipitation (ISP) process from PSE-like chicken meat. The ISP-isolated samples were solubilized at pH 11.0 and recovered at pH 5.5 and 6.2. The ultimate pH of the ISP-isolated protein and meat paste was adjusted to 6.2 and 7.0. The ultimate pH in this article referred to the final pH of the extracted protein and meat paste. Higher reactive sulfhydryl content and surface hydrophobicity were found in the precipitation at pH 6.2 than at pH 5.5. However, various ultimate pH values showed no significant influence on the surface hydrophobicity. The hardness of gel, as measured by textural profile analysis, was improved using 6.2 as the precipitation pH compared with pH 5.5. The viscoelastic modulus (G΄) of gel pastes prior to the thermal gelation was higher with ISP treatment. However, lower G΄ was seen after thermal gelation compared with the control. Dynamic rheological measurement demonstrated a different gel-forming mechanism for protein precipitated at pH values of 5.5 and 6.2 compared with the meat paste. The cooking loss showed that the recovered protein failed to form a gel with good water-retention capacity unless the ultimate pH was adjusted to 7.0. Gels made from protein extracted by the ISP method had higher yellowness and lower redness values, probably due to protein denaturation. Precipitation at pH 6.2 formed a harder gel with lower water-retention ability than that at pH 5.5, and this result was possibly due to higher surface hydrophobicity and S-S bridge formation. Overall, network characteristics of ISP-treated protein gels were strongly dependent on precipitation pH and ultimate pH. © 2016

Estimation of risks by chemicals produced during laser pyrolysis of tissues

Science.gov (United States)

Weber, Lothar W.; Spleiss, Martin

1995-01-01

Use of laser systems in minimal invasive surgery results in formation of laser aerosol with volatile organic compounds of possible health risk. By use of currently identified chemical substances an overview on possibly associated risks to human health is given. The class of the different identified alkylnitriles seem to be a laser specific toxicological problem. Other groups of chemicals belong to the Maillard reaction type, the fatty acid pyrolysis type, or even the thermally activated chemolysis. In relation to the available different threshold limit values the possible exposure ranges of identified substances are discussed. A rough estimation results in an exposure range of less than 1/100 for almost all substances with given human threshold limit values without regard of possible interactions. For most identified alkylnitriles, alkenes, and heterocycles no threshold limit values are given for lack of, until now, practical purposes. Pyrolysis of anaesthetized organs with isoflurane gave no hints for additional pyrolysis products by fragment interactions with resulting VOCs. Measurements of pyrolysis gases resulted in detection of small amounts of NO additionally with NO2 formation at plasma status.

Effect of pH on Separation of Solid Content from Paint Contained Wastewater by a Coagulant-flocculant Compound

Directory of Open Access Journals (Sweden)

Mojtaba Semnani Rahbar

2014-05-01

Full Text Available Chemical wastewater treatment is one of the attracting and common methods for wastewater treatment among the currently employed chemical unit processes. The use of coagulant-flocculant compound is one of the efficient methods for separating of paint and recovery of water. In this research, it was introduced and the effect of pH on removal of solid content from solution was studied experimentally. For this purpose, sludge and suspended solid content of the solution were determined in a jar test by measurement of UV absorption of treated solution and solid separation percentage. The results showed that in pH range 9.5-10.5, maximum efficiency of solid content removal was up to 95%. Consequently, maximum paint removal was obtained in this range of pH. The separation of solid content of the solution was due to formation of aluminum hydroxide. As shown by the results, the reduction of potassium hydroxide as pH adjuster caused decrease of pH and consequently decreases of aluminum hydroxide and solid content removal.  

Use of Tectonagrandis Leaf Extract in Colouring Silk Cloth Material Based on pH and Mordant Variations

Science.gov (United States)

Rosyida, A.; Suranto

2018-03-01

One of the very potential use of plant natural colour in the industrial activities was Anthocyanin. This substance contains in a number on plant organs such as Tectona Grandis (Fabaceae) particularly in their leaf materials. In order to get this secondary metabolism, the aim of this research was to find out the optimum condition of mordant and the pH combination in producing natural colour of Tectonagrandis leaf extract. To get this chemical substance, 1 kilogram of young leaves were cut into smaller size and soaked in 7 litre of H2O for 12 hour9. The solution was then boiled for 15 minutes. To get the best colour, variations of pH (5, 7 and 9) respectivelly were applied. The results showed that purple to redness were resulted when pH 5 and no additional mordant was added. Conversly the greyness to black, were produced when ferrosulphate were added. When the addition of alum was made the redies purple will appear. These colours were considered quite good quality under examination of grey and staining scales (4-5) after treated by both wet and dry rubbing methods. The test for wash fastness resulted in sufficiently good value of color change (value of 3 on Grey Scale standard), while test for staining demonstrated good staining (value of 4 on Staining Scale standard). This early finding was quite promosing to be applied in the near future in providing natural colours for industrial purposes.

Consumption of new psychoactive substances in a Spanish sample of research chemical users.

Science.gov (United States)

González, Débora; Ventura, Mireia; Caudevilla, Fernando; Torrens, Marta; Farre, Magi

2013-07-01

To know the pattern of use of new psychoactive substances (NPSs) in a Spanish sample of research chemical (RC) users and to deepen the RC user profile and risk reduction strategies employed. This study is a cross-sectional survey by means of a specific questionnaire. Recruitment was carried out at music festivals, at non-governmental organizations (NGOs), and through announcements on an online forum. Two RC user profiles were defined, according to whether they search information through online forums. A total of 230 users participated. The most frequent RCs were hallucinogenic phenethylamines (2C-B 80.0%, 2C-I 39.6%) and cathinones (methylone 40.1%, mephedrone 35.2%). The most frequent combination of RC with other illegal drugs was with cannabis (68.6%) and 2C-B with MDMA (28.3%). Subjects who are consulting drug forums (group 1) use more RC, obtain RC by Internet, and use more frequently risk prevention strategies. Regarding the risk-reduction strategies in this group, users sought information concerning RC before consuming them (100%), used precision scales to calculate dosage (72.3%), and analyzed the contents before consumption (68.8%). There is a specific RC user profile with extensive knowledge and consumption of substances, using different strategies to reduce risks associated to its consumption. Copyright © 2013 John Wiley & Sons, Ltd.

Characteristics of selected bioaccumulative substances and their impact on fish health

Directory of Open Access Journals (Sweden)

Walczak Marek

2016-12-01

Full Text Available The aim of this article was to evaluate the influence and effects of chosen bioaccumulative substances i.e. heavy metals, pesticides, and polychlorinated biphenyls (PCBs on fish, as well as provide information on time trends and potential threat to human health. Chemical substances which pollute water may affect living organisms in two ways. First of all, large amounts of chemical substances may cause sudden death of a significant part of the population of farmed fish, without symptoms (i.e. during breakdown of factories or industrial sewage leaks. However, more frequently, chemical substances accumulate in tissues of living organisms affecting them chronically. Heavy metals, pesticides, and polychlorinated biphenyls are persistent substances with a long-lasting biodegradation process. In a water environment they usually accumulate in sediments, which makes them resistant to biodegradation processes induced by, e.g., the UV light. These substances enter the fish through direct consumption of contaminated water or by contact with skin and gills. Symptoms of intoxication with heavy metals, pesticides, and PCBs may vary and depend on the concentration and bioavailability of these substances, physicochemical parameters of water, and the fish itself.

Investigation of Evaluation method of chemical runaway reaction

International Nuclear Information System (INIS)

Sato, Yoshihiko; Sasaya, Shinji; Kurakata, Koichiro; Nojiri, Ichiro

2002-02-01

Safety study 'Study of evaluation of abnormal occurrence for chemical substances in the nuclear fuel facilities' will be carried out from 2001 to 2005. In this study, the prediction of thermal hazards of chemical substances will be investigated and prepared. The hazard prediction method of chemical substances will be constructed from these results. Therefore, the hazard prediction methods applied in the chemical engineering in which the chemical substances with the hazard of fire and explosion were often treated were investigated. CHETAH (The ASTM Computer Program for Chemical Thermodynamic and Energy Release Evaluation) developed by ASTM (American Society for Testing and Materials) and TSS (Thermal Safety Software) developed by CISP (ChemInform St. Petersburg) were introduced and the fire and explosion hazards of chemical substances and reactions in the reprocessing process were evaluated. From these evaluated results, CHETAH could almost estimate the heat of reaction at 10% accuracy. It was supposed that CHETAH was useful as a screening for the hazards of fire and explosion of the new chemical substances and so on. TSS could calculate the reaction rate and the reaction behavior from the data measured by the various calorimeters rapidly. It was supposed that TSS was useful as an evaluation method for the hazards of fire and explosion of the new chemical reactions and so on. (author)

Investigations of the uptake of transuranic radionuclides by humic and fulvic acids chemically immobilized on silica gel and their competitive release by complexing agents

International Nuclear Information System (INIS)

Bulman, R.A.; Szabo, G.; Clayton, R.F.; Clayton, C.R.

1998-01-01

The chemistry of the interactions of transuranic elements (TUs) with humic substances needs to be understood so that humate-mediated movement of transuranic radionuclides through the environment can be predicted. This paper reports the chemical immobilization on silica gel of humic and fulvic acids and evaluates the potential of these new materials for the retention of Pu and Am. In addition to the preparation of the foregoing immobilized humic substances, other low molecular weight metal-binding ligands have also been immobilized on silica gel to investigate the binding sites for transuranic elements (TUs) in humic substances. The X-ray photoelectron spectra (XPS) of Th(IV) complexed by humic acid and the immobilized humic acid are similar thus it appears that immobilization of humic acid does not generate any configurational changes in the Th(IV)-binding sites of the macromolecule. A variety of chelating agents partly mobilize these TUs sorbed on the solid phases. A batch method was used to determine the distribution coefficients (R d ) of Pu and Am between the silica gels and aqueous solutions of phosphate and citrate. The effects of the immobilized ligands, the anions and pH in the solution on sorption were assessed. Distributed coefficients (R d ) for the uptake of Pu and Am by these prepared solid phases are, in some cases, of a similar order of magnitude as those determined for soil and particles suspended in terrestrial surface waters

Review of the state of the art of human biomonitoring for chemical substances and its application to human exposure assessment for food safety

DEFF Research Database (Denmark)

Choi, Judy; Mørck, Thit Aarøe; Polcher, Alexandra

2015-01-01

Human biomonitoring (HBM) measures the levels of substances in body fluids and tissues. Many countries have conducted HBM studies, yet little is known about its application towards chemical risk assessment, particularly in relation to food safety. Therefore a literature search was performed...... in several databases and conference proceedings for 2002 – 2014. Definitions of HBM and biomarkers, HBM techniques and requirements, and the possible application to the different steps of risk assessment were described. The usefulness of HBM for exposure assessment of chemical substances from food source...... safety areas (namely exposure assessment), and for the implementation of a systematic PMM approach. But further work needs to be done to improve usability. Major deficits are the lack of HBM guidance values on a considerable number of substance groups, for which health based guidance values (HBGVs) have...

Fluorescence spectroscopy as a tool for quality assessment of humic substances

Science.gov (United States)

Boguta, Patrycja

2016-04-01

*The studies were partly carried out within the framework of a research project. The project was financed from funds of National Science Center on the base of decision number DEC-2013/11/D/NZ9/02545. Fluorescence spectroscopy belongs to modern, non-destructive, rapid and relatively cheap methods, as well as for many years it was successfully used in studies of organic compounds in the fields of medicine, biology and chemistry. On the other hand, soil organic matter is a group of compounds with a complex spatial structure showing a large number of groups with different kinds of fluorophores. This could suggest the possibility of application of fluorescence spectroscopy in assessing the quality of humic substances as well as in monitoring of their chemical transformations. The aim of study was chemical description of humic and fulvic acids based on fluorescence spectra, as well as an attempt of evaluation of changes occurring under the influence of different pH and during interactions with various concentrations of metal. The humic and fulvic acids were isolated from chemically different soils. The measurements were carried out on Hitachi fluorescence spectrometer in solutions with a concentration of humic acids 40mg dm-3, at pH from 3 to 7, and for the evaluation of the metal impact: with increasing Zn concentrations (0-50mg dm-3). The fluorescence spectra were recorded in the form of synchronous and emission-excitation matrices (EEM). Studies have shown the presence of different groups of fluorophores. Synchronous spectra were characterized by a well-separated bands showing fluorescence in the area of low, medium and high wavelengths, suggesting the presence of structures, both weakly and strongly humified. EEM spectra revealed map of fluorophores within wide ranges of emission and excitation. Fluorophores differed in both position and intensity. The highest intensity was observed for compounds with the lowest humification degree which might be due to high amount

Chemical method of labelling proteins with the radionuclides of technetium at physiological condition

International Nuclear Information System (INIS)

Wong, D.W.

1983-01-01

A novel rapid chemical method of labeling plasma proteins, other compounds and/or substances containing protein with radionuclides of technetium such as sup(95m)Tc, sup(99m)Tc or sup(99)Tc at physiologic pH 7.4 condition, producing a sterile non-pyrogenic radioactive tracer material suitable for biological and medical uses. These radiolabeled protein substances are not denatured by the labeling process but retain their natural physiological and immunological properties. This novel labeling technique provides a simple and rapid means of labeling plasma proteins such as human serum albumin, fibrinogen, antibodies, hormones and enzymes with sup(95m)Tc or sup(99m)Tc for scintigraphic imaging which may allow visualization of thrombi, emboli, myocardial infarcts, infectious lesions or tumors

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.

A chemical–biological similarity-based grouping of complex substances as a prototype approach for evaluating chemical alternatives† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6gc01147k Click here for additional data file.

Science.gov (United States)

Grimm, Fabian A.; Iwata, Yasuhiro; Sirenko, Oksana; Chappell, Grace A.; Wright, Fred A.; Reif, David M.; Braisted, John; Gerhold, David L.; Yeakley, Joanne M.; Shepard, Peter; Seligmann, Bruce; Roy, Tim; Boogaard, Peter J.; Ketelslegers, Hans B.; Rohde, Arlean M.

2016-01-01

Comparative assessment of potential human health impacts is a critical step in evaluating both chemical alternatives and existing products on the market. Most alternatives assessments are conducted on a chemical-by-chemical basis and it is seldom acknowledged that humans are exposed to complex products, not individual substances. Indeed, substances of Unknown or Variable composition, Complex reaction products, and Biological materials (UVCBs) are ubiquitous in commerce yet they present a major challenge for registration and health assessments. Here, we present a comprehensive experimental and computational approach to categorize UVCBs according to global similarities in their bioactivity using a suite of in vitro models. We used petroleum substances, an important group of UVCBs which are grouped for regulatory approval and read-across primarily on physico-chemical properties and the manufacturing process, and only partially based on toxicity data, as a case study. We exposed induced pluripotent stem cell-derived cardiomyocytes and hepatocytes to DMSO-soluble extracts of 21 petroleum substances from five product groups. Concentration-response data from high-content imaging in cardiomyocytes and hepatocytes, as well as targeted high-throughput transcriptomic analysis of the hepatocytes, revealed distinct groups of petroleum substances. Data integration showed that bioactivity profiling affords clustering of petroleum substances in a manner similar to the manufacturing process-based categories. Moreover, we observed a high degree of correlation between bioactivity profiles and physico-chemical properties, as well as improved groupings when chemical and biological data were combined. Altogether, we demonstrate how novel in vitro screening approaches can be effectively utilized in combination with physico-chemical characteristics to group complex substances and enable read-across. This approach allows for rapid and scientifically-informed evaluation of health impacts of

Waste paper for recycling: Overview and identification of potentially critical substances

DEFF Research Database (Denmark)

Pivnenko, Kostyantyn; Eriksson, Eva; Astrup, Thomas Fruergaard

2015-01-01

by nearly 20% within the last decade or so, reaching a level of almost 72% in 2012. With increasing recycling rates, lower quality paper fractions may be included. This may potentially lead to accumulation or un-intended spreading of chemical substances contained in paper, e.g. by introducing chemicals...... contained in waste paper into the recycling loop. This study provides an overview of chemicals potentially present in paper and applies a sequential hazard screening procedure based on the intrinsic hazard, physical-chemical and biodegradability characteristics of the substances. Based on the results, 51...

pH and redox effects of building materials

International Nuclear Information System (INIS)

Van der Sloot, H.A.; Van Zomeren, A.; Meeussen, J.C.L.; De Nie, D.S.

2007-11-01

The application of relatively fine grained industrial slags as fill material in industrial terrains and parking lots has led to unacceptably elevated pH values and imposed reducing conditions in ground- and surface water. Based on the Dutch Building Materials Decree the materials applied were classified as category 1 materials (free use). There are no limits set to pH and redox in this regulation. In itself a lower or higher pH and a low redox potential are not necessarily critical. Only when the buffer capacity of the surroundings is exceeded, undesirable situations may develop. In this work, the release of alkaline and reducing substances has been studied to assess if regulatory controls are needed and how such controls could be implemented practically. Both pH and redox potential are unsuitable properties for this purpose as it is the buffer capacity of the releasing material and the buffer capacity of the receiving soil and water bodies that determine whether unacceptable conditions develop. As pH and redox are also affected by gas reactions (O2 and CO2), the evaluation becomes relatively complex. Using the chemical speciation-transport model ORCHESTRA, a scenario description has been developed to assess the release of alkaline and reducing species from slag by infiltration under unsaturated conditions. Proper acid neutralization and redox buffering data for the materials were determined. Based on the sophisticated model results, a simplified model description was applied to link observations to impact. Decision schemes for applications above groundwater and in surface water have been developed based on the buffer capacity and particle size distribution of the material to be used, the infiltration rate, the degree of exposure to O2 and CO2 from the atmosphere or from soil air and the dimensions of the application. This has led to a preliminary guidance on implementing rules for acceptance of materials in specific applications. The modeled release predictions

pH in Action

NARCIS (Netherlands)

Tijskens, L.M.M.; Biekman, E.S.A.

2001-01-01

Based on fundamental chemical relations, well-established in chemical engineering and chemical technology over almost a century, the effects of pH in food and agricultural products will be deduced for different situations and processes. Based on simple equilibria and dissociation of water, salts,

The advisory list for selvclassification of dangerous substances

DEFF Research Database (Denmark)

Niemelä, Jay Russell; Wedebye, Eva Bay; Nikolov, Nikolai Georgiev

All chemical substances marketed in the EU must be classified and labelled according to the regulation on classification and labelling of dangerous substances (7). Substances with harmonised classifications adopted in the EU are to be found on the List of harmonised classification and labelling...... this issue, the Danish Environmental Protection Agency published the Advisory Self-classification List /5/. This report describes the updating of this list. The Advisory Self-Classification list is created by the use of (Q)SARs ((Quantitative) Structure-Activity Relationships) to predict the effects...... Skin sensitisation The updated advisory list is available as an Excel file for download from DK-EPA's website and as an online searchable database. This includes the 23,922 chemicals with new advisory classifications resulting from this project, making in all, a total of 30,179 chemicals with advisory...

Revision of Import and Export Requirements for Controlled Substances, Listed Chemicals, and Tableting and Encapsulating Machines, Including Changes To Implement the International Trade Data System (ITDS); Revision of Reporting Requirements for Domestic Transactions in Listed Chemicals and Tableting and Encapsulating Machines; and Technical Amendments. Final rule.

Science.gov (United States)

2016-12-30

The Drug Enforcement Administration is updating its regulations for the import and export of tableting and encapsulating machines, controlled substances, and listed chemicals, and its regulations relating to reports required for domestic transactions in listed chemicals, gamma-hydroxybutyric acid, and tableting and encapsulating machines. In accordance with Executive Order 13563, the Drug Enforcement Administration has reviewed its import and export regulations and reporting requirements for domestic transactions in listed chemicals (and gamma-hydroxybutyric acid) and tableting and encapsulating machines, and evaluated them for clarity, consistency, continued accuracy, and effectiveness. The amendments clarify certain policies and reflect current procedures and technological advancements. The amendments also allow for the implementation, as applicable to tableting and encapsulating machines, controlled substances, and listed chemicals, of the President's Executive Order 13659 on streamlining the export/import process and requiring the government-wide utilization of the International Trade Data System (ITDS). This rule additionally contains amendments that implement recent changes to the Controlled Substances Import and Export Act (CSIEA) for reexportation of controlled substances among members of the European Economic Area made by the Improving Regulatory Transparency for New Medical Therapies Act. The rule also includes additional substantive and technical and stylistic amendments.

THE PREDICTION OF pH BY GIBBS FREE ENERGY MINIMIZATION IN THE SUMP SOLUTION UNDER LOCA CONDITION OF PWR

Directory of Open Access Journals (Sweden)

HYOUNGJU YOON

2013-02-01

Full Text Available It is required that the pH of the sump solution should be above 7.0 to retain iodine in a liquid phase and be within the material compatibility constraints under LOCA condition of PWR. The pH of the sump solution can be determined by conventional chemical equilibrium constants or by the minimization of Gibbs free energy. The latter method developed as a computer code called SOLGASMIX-PV is more convenient than the former since various chemical components can be easily treated under LOCA conditions. In this study, SOLGASMIX-PV code was modified to accommodate the acidic and basic materials produced by radiolysis reactions and to calculate the pH of the sump solution. When the computed pH was compared with measured by the ORNL experiment to verify the reliability of the modified code, the error between two values was within 0.3 pH. Finally, two cases of calculation were performed for the SKN 3&4 and UCN 1&2. As results, pH of the sump solution for the SKN 3&4 was between 7.02 and 7.45, and for the UCN 1&2 plant between 8.07 and 9.41. Furthermore, it was found that the radiolysis reactions have insignificant effects on pH because the relative concentrations of HCl, HNO3, and Cs are very low.

Separation of enantiomers of new psychoactive substances by high-performance liquid chromatography.

Science.gov (United States)

Kadkhodaei, Kian; Forcher, Lisa; Schmid, Martin G

2018-03-01

New psychoactive substances are defined as compounds with consciousness-changing effects and have been developed simultaneously with classical drugs. They arise through structural modifications of illegal substances and are mainly produced to circumvent laws. Availability is simple, since new psychoactive substances can be purchased from the Internet. Among them many chemical drug compound classes are chiral and thus the two resulting enantiomers can differ in their effects. The aim of this study is to develop a suitable chiral high-performance liquid chromatography separation method for a broad spectrum of new psychoactive substances using cellulose tris(3,5-dichlorophenylcarbamate) as a chiral selector. Experiments were performed by high-performance liquid chromatography in normal-phase mode under isocratic conditions using ultraviolet detection. Direct separation was carried out on a high-performance liquid chromatography column (Lux® i-Cellulose-5, 3.5 μm, Phenomenex®), available since 2016. Excellent separation results were obtained for cathinones. After further optimization, even 47 instead of 39 out of 52 cathinones showed baseline separation. For amphetamine derivatives, satisfactory results were not achieved. Further, new psychoactive substances from other compound classes such as benzofuranes, thiophenes, phenidines, phenidates, morpholines, and ketamines were partially resolved, depending on the polarity and degree of substitution. All analytes, which were mainly purchased from the Internet, were proven to be traded as racemates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aerial vehicle with paint for detection of radiological and chemical warfare agents

Science.gov (United States)

Farmer, Joseph C.; Brunk, James L.; Day, S. Daniel

2013-04-02

A paint that warns of radiological or chemical substances comprising a paint operatively connected to the surface, an indicator material carried by the paint that provides an indication of the radiological or chemical substances, and a thermo-activation material carried by the paint. In one embodiment, a method of warning of radiological or chemical substances comprising the steps of painting a surface with an indicator material, and monitoring the surface for indications of the radiological or chemical substances. In another embodiment, a paint is operatively connected to a vehicle and an indicator material is carried by the paint that provides an indication of the radiological or chemical substances.

High acidity tolerance in lichens with fumarprotocetraric, perlatolic or thamnolic acids is correlated with low pKa1 values of these lichen substances

International Nuclear Information System (INIS)

Hauck, Markus; Juergens, Sascha-Rene; Huneck, Siegfried; Leuschner, Christoph

2009-01-01

The depsidone fumarprotocetraric acid as well as the depsides perlatolic and thamnolic acids are lichen secondary metabolites. Their first dissociation constants (pK a1 ) in methanol were determined to be 2.7 for perlatolic acid and 2.8 for fumarprotocetraric and thamnolic acids by UV spectroscopy. Lower pK a1 values are, so far, not known from lichen substances. Several lichens producing at least one of these compounds are known for their outstanding tolerance to acidic air pollution. This is demonstrated by evaluating published pH preferences for central European lichens. The low pK a1 values suggest that strong dissociation of the studied lichen substances is a prerequisite for the occurrence of lichens with these compounds on very acidic substrata, as protonated lichen substances of different chemical groups, but not their conjugated bases, are known to shuttle protons into the cytoplasm and thereby apparently damage lichens. - Depsides and depsidones with low pK a1 values occur in highly acidity-tolerant lichens.

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.

Electrolytic extraction drives volatile fatty acid chain elongation through lactic acid and replaces chemical pH control in thin stillage fermentation.

Science.gov (United States)

Andersen, Stephen J; Candry, Pieter; Basadre, Thais; Khor, Way Cern; Roume, Hugo; Hernandez-Sanabria, Emma; Coma, Marta; Rabaey, Korneel

2015-01-01

Volatile fatty acids (VFA) are building blocks for the chemical industry. Sustainable, biological production is constrained by production and recovery costs, including the need for intensive pH correction. Membrane electrolysis has been developed as an in situ extraction technology tailored to the direct recovery of VFA from fermentation while stabilizing acidogenesis without caustic addition. A current applied across an anion exchange membrane reduces the fermentation broth (catholyte, water reduction: H2O + e(-) → ½ H2 + OH(-)) and drives carboxylate ions into a clean, concentrated VFA stream (anolyte, water oxidation: H2O → 2e(-) + 2 H(+) + O2). In this study, we fermented thin stillage to generate a mixed VFA extract without chemical pH control. Membrane electrolysis (0.1 A, 3.22 ± 0.60 V) extracted 28 ± 6 % of carboxylates generated per day (on a carbon basis) and completely replaced caustic control of pH, with no impact on the total carboxylate production amount or rate. Hydrogen generated from the applied current shifted the fermentation outcome from predominantly C2 and C3 VFA (64 ± 3 % of the total VFA present in the control) to majority of C4 to C6 (70 ± 12 % in the experiment), with identical proportions in the VFA acid extract. A strain related to Megasphaera elsdenii (maximum abundance of 57 %), a bacteria capable of producing mid-chain VFA at a high rate, was enriched by the applied current, alongside a stable community of Lactobacillus spp. (10 %), enabling chain elongation of VFA through lactic acid. A conversion of 30 ± 5 % VFA produced per sCOD fed (60 ± 10 % of the reactive fraction) was achieved, with a 50 ± 6 % reduction in suspended solids likely by electro-coagulation. VFA can be extracted directly from a fermentation broth by membrane electrolysis. The electrolytic water reduction products are utilized in the fermentation: OH(-) is used for pH control without added chemicals, and H2 is

Ab initio quantum chemical calculation as a tool of evaluating diamagnetic susceptibility of magnetically levitating substances

International Nuclear Information System (INIS)

Fujiwara, Y; Tanimoto, Y

2009-01-01

On magnetic force evaluation necessary for magnetically levitated diamagnetic substances, isotropic diamagnetic susceptibility estimation by the ab initio quantum chemical calculation using Gaussian03W was verified for more than 300 molecules in a viewpoint of the accuracy in the absolute value and the calculation level affording good cost performance. From comparison, the method of B3PW91 / 6-311+G(d,p) was found to give the adequate absolute value by the relation of (observed) = (1.03 ± 0.005) x (calculated) - (1.22 ± 0.60) x 10 -6 in a unit of cm 3 mol -1 and good cost performance.

Ab initio quantum chemical calculation as a tool of evaluating diamagnetic susceptibility of magnetically levitating substances

Energy Technology Data Exchange (ETDEWEB)

Fujiwara, Y [Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Tanimoto, Y [Faculty of Pharmacy, Osaka Ohtani University, Nishikiorikita, Tondabayashi 584-8540 (Japan)], E-mail: fuji0710@sci.hiroshima-u.ac.jp

2009-03-01

On magnetic force evaluation necessary for magnetically levitated diamagnetic substances, isotropic diamagnetic susceptibility estimation by the ab initio quantum chemical calculation using Gaussian03W was verified for more than 300 molecules in a viewpoint of the accuracy in the absolute value and the calculation level affording good cost performance. From comparison, the method of B3PW91 / 6-311+G(d,p) was found to give the adequate absolute value by the relation of (observed) = (1.03 {+-} 0.005) x (calculated) - (1.22 {+-} 0.60) x 10{sup -6} in a unit of cm{sup 3} mol{sup -1} and good cost performance.

CHANGES IN STRUCTURE AND CONTENT HUMIC SUBSTANCES

Directory of Open Access Journals (Sweden)

Maroš SIROTIAK

2016-06-01

Full Text Available The paper deals with the process of thermal degradation of humic substances in soil samples exposed to increased temperature. To determine the basic properties of humic substances, humic and fulvic acids are used conventional fractionation chemical laboratory methods. To determine changes in the chemical structure, the method of use of FT-IR ATR spectroscopy technique.

77 FR 43520 - Significant New Use Rules on a Certain Chemical Substance; Removal of Significant New Use Rules

Science.gov (United States)

2012-07-25

... April 27, 2012 (77 FR 25236) (FRL-9343-4). If you have questions regarding the applicability of this... (77 FR 25236). If you have questions, consult the technical person listed under FOR FURTHER... 2070-AB27 Significant New Use Rules on a Certain Chemical Substance; Removal of Significant New Use...

Physico-chemical changes of ZnO nanoparticles with different size and surface chemistry under physiological pH conditions.

Science.gov (United States)

Gwak, Gyeong-Hyeon; Lee, Won-Jae; Paek, Seung-Min; Oh, Jae-Min

2015-03-01

We studied the physico-chemical properties of ZnO nanoparticles under physiological pH conditions (gastric, intestinal and plasma) as functions of their size (20 and 70 nm) and surface chemistry (pristine, L-serine, or citrate coating). ZnO nanoparticles were dispersed in phosphate buffered saline under physiological pH conditions and aliquots were collected at specific time points (0.5, 1, 4, 10 and 24 h) for further characterization. The pH values of the aqueous ZnO colloids at each condition were in the neutral to slightly basic range and showed different patterns depending on the original size and surface chemistry of the ZnO nanoparticles. The gastric pH condition was found to significantly dissolve ZnO nanoparticles up to 18-30 wt%, while the intestinal or plasma pH conditions resulted in much lower dissolution amounts than expected. Based on the X-ray diffraction patterns and X-ray absorption spectra, we identified partial phase transition of the ZnO nanoparticles from wurtzite to Zn(OH)2 under the intestinal and plasma pH conditions. Using scanning electron microscopy, we verified that the overall particle size and morphology of all ZnO nanoparticles were maintained regardless of the pH. Copyright © 2015 Elsevier B.V. All rights reserved.

A Comprehensive Substance Abuse Counselor Education Program: From Specialty Certificate to Ph.D.

Science.gov (United States)

Goodwin, Lloyd R., Jr.

2006-01-01

East Carolina University has one of the few comprehensive substance abuse counselor education (SACE) programs in the nation that offers an undergraduate, master's, and doctoral level of preparation in substance abuse counseling. This article describes the evolution of this SACE from its beginning in 1972 to its current status. This comprehensive…

Equilibrium unfolding of A. niger RNase: pH dependence of chemical and thermal denaturation.

Science.gov (United States)

Kumar, Gundampati Ravi; Sharma, Anurag; Kumari, Moni; Jagannadham, Medicherla V; Debnath, Mira

2011-08-01

Equilibrium unfolding of A. niger RNase with chemical denaturants, for example GuHCl and urea, and thermal unfolding have been studied as a function of pH using fluorescence, far-UV, near-UV, and absorbance spectroscopy. Because of their ability to affect electrostatic interactions, pH and chemical denaturants have a marked effect on the stability, structure, and function of many globular proteins. ANS binding studies have been conducted to enable understanding of the folding mechanism of the protein in the presence of the denaturants. Spectroscopic studies by absorbance, fluorescence, and circular dichroism and use of K2D software revealed that the enzyme has α + β type secondary structure with approximately 29% α-helix, 24% β-sheet, and 47% random coil. Under neutral conditions the enzyme is stable in urea whereas GuHCl-induced equilibrium unfolding was cooperative. A. niger RNase has little ANS binding even under neutral conditions. Multiple intermediates were populated during the pH-induced unfolding of A. niger RNase. Urea and temperature-induced unfolding of A. niger RNase into the molten globule-like state is non-cooperative, in contrast to the cooperativity seen with the native protein, suggesting the presence of two parts/domains, in the molecular structure of A. niger RNase, with different stability that unfolds in steps. Interestingly, the GuHCl-induced unfolding of the A state (molten globule state) of A. niger RNase is unique, because a low concentration of denaturant not only induces structural change but also facilitates transition from one molten globule like state (A(MG1)) into another (I(MG2)).

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

Microbiology and atmospheric processes: chemical interactions of primary biological aerosols

Directory of Open Access Journals (Sweden)

L. Deguillaume

2008-07-01

Full Text Available This paper discusses the influence of primary biological aerosols (PBA on atmospheric chemistry and vice versa through microbiological and chemical properties and processes. Several studies have shown that PBA represent a significant fraction of air particulate matter and hence affect the microstructure and water uptake of aerosol particles. Moreover, airborne micro-organisms, namely fungal spores and bacteria, can transform chemical constituents of the atmosphere by metabolic activity. Recent studies have emphasized the viability of bacteria and metabolic degradation of organic substances in cloud water. On the other hand, the viability and metabolic activity of airborne micro-organisms depend strongly on physical and chemical atmospheric parameters such as temperature, pressure, radiation, pH value and nutrient concentrations. In spite of recent advances, however, our knowledge of the microbiological and chemical interactions of PBA in the atmosphere is rather limited. Further targeted investigations combining laboratory experiments, field measurements, and modelling studies will be required to characterize the chemical feedbacks, microbiological activities at the air/snow/water interface supplied to the atmosphere.

PENGARUH VARIASI PH TERHADAP KADAR FLAVONOID PADA EKSTRAKSI PROPOLIS DAN KARAKTERISTIKNYA SEBAGAI ANTIMIKROBA

Directory of Open Access Journals (Sweden)

Suci Nurfazri Rismawati

2017-10-01

ABSTRACT Propolis has been recognized among people as a medicine, and health food. Propolis is a resin substance collected by honey bee from various plants that have properties such as antimicrobials, antioxidants, apoptosis and anti-cancer. Propolis is a hard resin substance, it needs an extraction process to get propolis ready for consumption. The purpose of this study was to analyze the influence of pH variation on the extraction process of propolis with water solvent and its characterization as an antimicrobial agent. The extraction was done by maceration technique, with the ratio of propolis powder and solvent was 2: 8, with variation of pH 2,4,6,8 and 10. Flavonoids were measured by colorimetric complexation method of aluminum - flavonoids. Antimicrobial activity against Staphylococcus aureus was measured by the disk diffusion method and the formation of the inhibitory zone. From the standard series obtained regression of 0.9995 and the highest flavonoid content obtained by using water solvent pH 8 which is equal to 62.6098 ppm. Antibacterial activity of propolis showed positive result form resistor zone on water solvent pH 8 which is about 2.0 mm. The linear equation equation equation is y = 5,6029x - 4,2001 with with R2 is 0,8289. The optimum flavonoid content is indicated on the extraction at pH 8    Keywords: antimicrobial activity, flavonoids, pH, propolis

40 CFR 723.175 - Chemical substances used in or for the manufacture or processing of instant photographic and peel...

Science.gov (United States)

2010-07-01

... manufacture and processing in the special production area. All manufacturing, processing, and use operations... shape or design during manufacture, (ii) which has end use function(s) dependent in whole or in part... production area, the ambient air concentration of the new chemical substance during manufacture, processing...

Toxic substances handbook

Science.gov (United States)

Junod, T. L.

1979-01-01

Handbook, published in conjunction with Toxic Substances Alert Program at NASA Lewis Research Center, profiles 187 toxic chemicals in their relatively pure states and include 27 known or suspected carcinogens.

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

International Nuclear Information System (INIS)

Halton, D.M.

1986-12-01

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

Extracellular Polymeric Substances Govern the Surface Charge of Biogenic Elemental Selenium Nanoparticles

KAUST Repository

Jain, Rohan

2015-02-03

© 2014 American Chemical Society. The origin of the organic layer covering colloidal biogenic elemental selenium nanoparticles (BioSeNPs) is not known, particularly in the case when they are synthesized by complex microbial communities. This study investigated the presence of extracellular polymeric substances (EPS) on BioSeNPs. The role of EPS in capping the extracellularly available BioSeNPs was also examined. Fourier transform infrared (FT-IR) spectroscopy and colorimetric measurements confirmed the presence of functional groups characteristic of proteins and carbohydrates on the BioSeNPs, suggesting the presence of EPS. Chemical synthesis of elemental selenium nanoparticles in the presence of EPS, extracted from selenite fed anaerobic granular sludge, yielded stable colloidal spherical selenium nanoparticles. Furthermore, extracted EPS, BioSeNPs, and chemically synthesized EPS-capped selenium nanoparticles had similar surface properties, as shown by ζ-potential versus pH profiles and isoelectric point measurements. This study shows that the EPS of anaerobic granular sludge form the organic layer present on the BioSeNPs synthesized by these granules. The EPS also govern the surface charge of these BioSeNPs, thereby contributing to their colloidal properties, hence affecting their fate in the environment and the efficiency of bioremediation technologies.

Chemical Composition and Evaluation of Nicotine, Tobacco Alkaloids, pH and Selected Flavors in e-Cigarette Cartridges and Refill Solutions

Science.gov (United States)

Lisko, Joseph G.; Tran, Hang; Stanfill, Stephen B.; Blount, Benjamin C.; Watson, Clifford H.

2015-01-01

Introduction Electronic cigarette (e-cigarette) use is increasing dramatically in developed countries, but little is known about these rapidly evolving products. This study analyzed and evaluated the chemical composition including nicotine, tobacco alkaloids, pH and flavors in 36 e-liquids brands from four manufacturers. Methods We determined the concentrations of nicotine, alkaloids, and select flavors and measured pH in solutions used in e-cigarettes. E-cigarette products were chosen based upon favorable consumer approval ratings from online review websites. Quantitative analyses were performed using strict quality assurance/quality control (QC) validated methods previously established by our lab for the measurement of nicotine, alkaloids, pH and flavors. Results Three-quarters of the products contained lower measured nicotine levels than the stated label values (6% - 42% by concentration). The pH for e-liquids ranged from 5.1 – 9.1. Minor tobacco alkaloids were found in all samples containing nicotine, and their relative concentrations varied widely among manufacturers. A number of common flavor compounds were analyzed in all e-liquids. Conclusions Free nicotine levels calculated from the measurement of pH correlated with total nicotine content. The direct correlation between the total nicotine concentration and pH suggests that the alkalinity of nicotine drives the pH of e-cigarette solutions. A higher percentage of nicotine exists in the more absorbable free form as total nicotine concentration increases. A number of products contained tobacco alkaloids at concentrations that exceed U.S. Pharmacopeia limits for impurities in nicotine used in pharmaceutical and food products. PMID:25636907

Influence of humic substances on plant-microbes interactions in the rhizosphere

Science.gov (United States)

Puglisi, Edoardo; Pascazio, Silvia; Spaccini, Riccardo; Crecchio, Carmine; Trevisan, Marco; Piccolo, Alessandro

2013-04-01

Humic substances are known to play a wide range of effects on the physiology of plant and microbes. This is of particular relevance in the rhizosphere of terrestrial environments, where the reciprocal interactions between plants roots, soil constituents and microorganisms strongly influence the plants acquisition of nutrients. Chemical advances are constantly improving our knowledge on humic substances: their supra-molecular architecture, as well as the moltitude of their chemical constituents, many of which are biologically active. An approach for linking the structure of humic substances with their biological activity in the rhizosphere is the use of rhizoboxes, which allow applying a treatment (e.g., an amendment with humic substances) in an upper soil-plant compartment and take measurements in a lower isolated rhizosphere compartment that can be sampled at desired distances from the rhizoplane. This approach can be adopted to assess the effects of several humic substances, as well as composted materials, on maize plants rhizodeposition of carbon, and in turn on the structure and activity of rhizosphere microbial communities. In order to gain a complete understanding of processes occurring in the complex soil-plant-microorganisms tripartite system, rhizobox experiments can be coupled with bacterial biosensors for the detection and quantification of bioavailable nutrients, chemical analyses of main rhizodeposits constituents, advanced chemical characterizations of humic substances, DNA-fingerprinting of microbial communities, and multivariate statistical approaches to manage the dataset produced and to infer general conclusions. By such an approach it was found that humic substances are significantly affecting the amount of carbon deposited by plant roots. This induction effect is more evident for substances with more hydrophobic and complex structure, thus supporting the scientific hypothesis of the "microbial loop model", which assumes that plants feed

Substance Abuse and the Family.

Science.gov (United States)

Murphy, John P.

1984-01-01

Examines the effect that a substance abuser may have on the family system and the maladaptive roles sometimes assumed by family members. Discusses dysfunctional family phases and therapeutic issues and presents 11 guidelines for counselors working with chemically dependent families. (JAC)

Production of pigment-free pullulan by swollen cell in Aureobasidium pullulans NG which cell differentiation was affected by pH and nutrition.

Science.gov (United States)

Li, Bing-xue; Zhang, Ning; Peng, Qing; Yin, Tie; Guan, Fei-fei; Wang, Gui-li; Li, Ying

2009-08-01

A black yeast strain "NG" was isolated from strawberry fruit and identified as Aureobasidium pullulans. Strain NG displayed yeast-like cell (YL), swollen cell (SC), septate swollen cell (SSC), meristematic structure (MS), and chlamydospore (CH) morphologies. pH was the key factor regulating cell morphogenesis of strain NG. Differentiation of YL controlled by extracellular pH had no relationship with nutrition level. YL was maintained at pH >6.0, but was transformed into SC at pH approximately 4.5. SC, a stable cell type of A. pullulans, could bud, septate, or transform into MS or CH, in response to nutrition level and low pH. SC produced swollen cell blastospores (SCB) at pH 2.1 with abundant nutrition, and could transform into MS at lower pH (1.5). SC was induced to form CH by low level nutrition and pH melanin) were produced by SC of strain NG. Pullulan content of the polysaccharides was very high (98.37%). Fourier-transform infrared spectroscopy confirmed that chemical structures of the polysaccharides and standard pullulan were identical. Swollen cells produced 2.08 mg/ml non-pigmented polysaccharides at 96 h in YPD medium. Controlling pH of fermentation is an effective and convenient method to harvest SC for melanin-free pullulan production.

77 FR 48858 - Significant New Use Rules on Certain Chemical Substances

Science.gov (United States)

2012-08-15

... adverse chronic effects from the presumed degradation product of this PMN substance on humans and wildlife...) human exposure to the substance and its potential degradation products. To protect against these risks... may be significant (or substantial) human exposure to the substances and their potential degradation...

Ultrafiltration and nanofiltration membrane fouling by natural organic matter: Mechanisms and mitigation by pre-ozonation and pH.

Science.gov (United States)

Yu, Wenzheng; Liu, Teng; Crawshaw, John; Liu, Ting; Graham, Nigel

2018-08-01

The fouling of ultrafiltration (UF) and nanofiltration (NF) membranes during the treatment of surface waters continues to be of concern and the particular role of natural organic matter (NOM) requires further investigation. In this study the effect of pH and surface charge on membrane fouling during the treatment of samples of a representative surface water (Hyde Park recreational lake) were evaluated, together with the impact of pre-ozonation. While biopolymers in the surface water could be removed by the UF membrane, smaller molecular weight (MW) fractions of NOM were poorly removed, confirming the importance of membrane pore size. For NF membranes the removal of smaller MW fractions (800 Da-10 kDa) was less than expected from their pore size; however, nearly all of the hydrophobic, humic-type substances could be removed by the hydrophilic NF membranes for all MW distributions (greater than 90%). The results indicated the importance of the charge and hydrophilic nature of the NOM. Thus, the hydrophilic NF membrane could remove the hydrophobic organic matter, but not the hydrophilic substances. Increasing charge effects (more negative zeta potentials) with increasing solution pH were found to enhance organics removal and reduce fouling (flux decline), most likely through greater membrane surface repulsion. Pre-ozonation of the surface water increased the hydrophilic fraction and anionic charge of NOM and altered their size distributions. This resulted in a decreased fouling (less flux decline) for the UF and smaller pore NF, but a slight increase in fouling for the larger pore NF. The differences in the NF behavior are believed to relate to the relative sizes of ozonated organic fractions and the NF pores; a similar size of ozonated organic fractions and the NF pores causes significant membrane fouling. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Influence on Levels of Information as Presented by Different Technologies on Students' Understanding of Acid, Base, and pH Concepts.

Science.gov (United States)

Nakhleh, Mary B.; Krajcik, Joseph S.

1994-01-01

Involves secondary students in a study designed to allow investigation into how different levels of information presented by various technologies (chemical indicators, pH meters, and microcomputer-based laboratories-MBLs) affected students' understanding of acid, base, and pH concepts. Results showed that students using MBLs exhibited a greater…

Chemical Composition and Evaluation of Nicotine, Tobacco Alkaloids, pH, and Selected Flavors in E-Cigarette Cartridges and Refill Solutions.

Science.gov (United States)

Lisko, Joseph G; Tran, Hang; Stanfill, Stephen B; Blount, Benjamin C; Watson, Clifford H

2015-10-01

Electronic cigarette (e-cigarette) use is increasing dramatically in developed countries, but little is known about these rapidly evolving products. This study analyzed and evaluated the chemical composition including nicotine, tobacco alkaloids, pH, and flavors in 36 e-liquids brands from 4 manufacturers. We determined the concentrations of nicotine, alkaloids, and select flavors and measured pH in solutions used in e-cigarettes. E-cigarette products were chosen based upon favorable consumer approval ratings from online review websites. Quantitative analyses were performed using strict quality assurance/quality control validated methods previously established by our lab for the measurement of nicotine, alkaloids, pH, and flavors. Three-quarters of the products contained lower measured nicotine levels than the stated label values (6%-42% by concentration). The pH for e-liquids ranged from 5.1-9.1. Minor tobacco alkaloids were found in all samples containing nicotine, and their relative concentrations varied widely among manufacturers. A number of common flavor compounds were analyzed in all e-liquids. Free nicotine levels calculated from the measurement of pH correlated with total nicotine content. The direct correlation between the total nicotine concentration and pH suggests that the alkalinity of nicotine drives the pH of e-cigarette solutions. A higher percentage of nicotine exists in the more absorbable free form as total nicotine concentration increases. A number of products contained tobacco alkaloids at concentrations that exceed U.S. pharmacopeia limits for impurities in nicotine used in pharmaceutical and food products. © Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Comparison of point-source pollutant loadings to soil and groundwater for 72 chemical substances.

Science.gov (United States)

Yu, Soonyoung; Hwang, Sang-Il; Yun, Seong-Taek; Chae, Gitak; Lee, Dongsu; Kim, Ki-Eun

2017-11-01

the chemical ranking systems. In the surface spill scenario, the pollutant loadings were zeros for all chemicals, except methylamine to soil whose pollutant loading was smaller than that in the subsurface leak scenario by 4 orders of magnitude. The maximum mass and the average mass multiplied by duration in soil greatly depended on leaching fluxes (r = 1.0 and 0.9, respectively), while the effect of leaching fluxes diminished below the water table. The contribution of this work is that a physics-based numerical model was used to quantitatively compare the subsurface pollutant loading in a chemical accident for 72 chemical substances, which can scientifically defend a simpler and more qualitative assessment of pollutant loadings. Besides, this study assessed pollutant loadings to soil (unsaturated zone) and groundwater (saturated zone) all together and discussed their interactions.

DETERMINATION OF SOME PHYSICAL AND CHEMICAL PROPERTIES OF PECTIN SUBSTANCES FROM THE SOLVENT CAKE OF TAGETES PATULA L. INFLORESCENCES

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N. M. Chervonnaya

2017-01-01

Full Text Available Big molecular weight conditions are responsible for some properties, which are absent in low molecular compounds. Therefore, its determination allows revealing of some physical and technological properties of biopolymers and prediction of the possibility of their practical application. The aim of this work was to determine an average molarweight, to study the superficial properties at the border of “solution-air” phases, and to establish an isoelectric spot of water solutions of pectin substances (PS, isolated from a solvent cake of Tagetes patula inflorescences. Materials and methods. Polysaccharide complexes were isolated from the solvent cake of Tagetes patula inflorescences of Carmen species which was left after a raw material extraction with ethanol 40% with the method of Kochetkov and M. Sinnera. The time of water and PS solutions flow out was measured by the use of a capillary Ostwald viscosimeter; different types of viscosity were calculated. The density of solutions was determined by using a picnometric method, however due to the closeness of density of the analyzed solutions and water, they were not considered in the calculation of the relative viscosity. Series of solutions with 0.01 to 0.5% concentrations were prepared from 1% PS water solutions to determine a surface activity. Monometric liquid tension variations were set in Rehbinder’s apparatus in the moment of an air bubble appearance on the surface of PS solution. Isoelectric spot (IES of PS was determined in acetate buffer solution with pH within 3.2 to 6.2 by using the viscometer method. Results and discussion. Fractioning of the obtained polysaccharide complexes showed that efficiency of the pectin substances amounted to 2.2%. Calculation shows that an average molar weight of PS amounted to 45272 g/mol. About the degree of interaction between macromolecules of polymer and solvent, structural properties of macromolecule, the degree of its branching can be judged by the

Hazardous substances in Europe's fresh and marine waters

DEFF Research Database (Denmark)

Collins, Robert; Brack, Werner; Lützhøft, Hans-Christian Holten

Chemicals are an essential part of our daily lives. They are used to produce consumer goods, to protect or restore our health and to boost food production, to name but a few examples — and they are also involved in a growing range of environmental technologies. Europe's chemical and associated...... on their pattern of use and the potential for exposure. Certain types of naturally occurring chemicals, such as metals, can also be hazardous. Emissions of hazardous substances to the environment can occur at every stage of their life cycle, from production, processing, manufacturing and use in downstream...... regarding chemical contamination arising from the exploitation of shale gas has grown recently. Hazardous substances in water affect aquatic life… Hazardous substances are emitted to water bodies both directly and indirectly through a range of diffuse and point source pathways. The presence of hazardous...

Habit-associated salivary pH changes in oral submucous fibrosis-A controlled cross-sectional study.

Science.gov (United States)

Donoghue, Mandana; Basandi, Praveen S; Adarsh, H; Madhushankari, G S; Selvamani, M; Nayak, Prachi

2015-01-01

Oral submucous fibrosis (OSF) is a multi-causal inflammatory reaction to the chemical or mechanical trauma caused due to exposure to arecanut containing products with or without tobacco (ANCP/T). Arecanut and additional components such as lime and chewing tobacco render ANCP/T highly alkaline. Fibrosing repair is a common reaction to an alkaline exposure in the skin. OSF may be related to the alkaline exposure by ANCP/T in a similar manner. The study was aimed at establishing the relationship of habit-associated salivary pH changes and OSF. The study design was controlled cross-sectional. Base line salivary pH (BLS pH), salivary pH after chewing the habitual ANCP/T substance, post chew salivary pH (PCSpH) for 2 min and salivary pH recovery time (SpHRT) were compared in 30 OSF patients and 30 sex-matched individuals with ANCP/T habits and apparently healthy oral mucosa. The group's mean BLSpH values were similar and within normal range and representative of the population level values. The average PCSpH was significantly higher (P ˂ 0.0001) than the average BLSpH in both groups. There was no significant difference (P = 0.09) between PCSpH of OSF patients and controls. OSF patients had a significantly longer (P = 0.0076) SpHRT than controls. Factors such as age, daily exposure, cumulative habit years, BLSpH and PCSpH, had varying effects on the groups. Chewing ANCP/T causes a significant rise in salivary pH of all individuals. SpHRT has a significant association with OSF. The effect of salivary changes in OSF patients differs with those in healthy controls.

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...

Study of specific pharmacological activity of standardized composition of bee product substances for treatment of urogenital system

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V. M. Koval

2017-10-01

Full Text Available Introduction. The work presents review of the data literature, which indicate the prospects of creation new highly efficient drugs for the treatment of chronic prostatitis and prostate gland adenoma based bioactive standardized substances of bee products, including powdered honey (PH, propolis phenolic hydrophobic drug (PPHD and bee pollen (BP. Materials and methods. Results of discussion of preclinical pharmacological studies of standardized substances of bee products composition – PH, PPHD and BP for the treatment of specified pathology is given in the experimental part. Results. It was found that the most pronounced anti-inflammatory effect on the level 40 % the mixture of APIs (PH, PPHD and BP detects at a dose of 100 mg/kg in relation to the reference drug – trianom capsules in doses of 100 and 130 mg/kg. Conclusions. Usage of bee products is grounded in creation of the new drug on their basis in the form of standardized substances of bee products composition –PH, PPHD and BP for chronic prostatitis and prostate gland adenoma. It was found that the most pronounced anti-inflammatory effect on 40 % the mixture of APIs (PH, PPHD and BP detects at a dose of 100 mg/kg. It was established that the composition of standard substances of bee products – PH, PPHD and BP at a dose of 100 mg/kg shows a more pronounced specific pharmacological effect in comparison to the reference product – trianom capsules at doses of 100 and 130 mg/kg, which positively affect the course of the pilot prostatitis in male rats caused by dichloroethyl.

Production of antimicrobial substances by Bacillus subtilis LFE-1, B. firmus HO-1 and B. licheniformis T6-5 isolated from an oil reservoir in Brazil.

Science.gov (United States)

Korenblum, E; der Weid, I; Santos, A L S; Rosado, A S; Sebastián, G V; Coutinho, C M L M; Magalhães, F C M; Paiva, M M; Seldin, L

2005-01-01

Forty Bacillus strains isolated from a Brazilian oil reservoir were tested against each other to select strains producing antimicrobial substances (AMS). Three strains, Bacillus subtilis (LFE-1), Bacillus firmus (H2O-1) and Bacillus licheniformis (T6-5), were selected due to their ability to inhibit more than 65% of the Bacillus strains tested. These three strains were also investigated for their capability to inhibit sulphate-reducing bacteria (SRB). Furthermore, physiological and biochemical characteristics of the antimicrobial compounds produced by the selected strains were determined. Among the forty strains tested, 36 (90%) strains were able to inhibit at least one Bacillus strain used as indicator in plate assays and three of them (LFE-1, T6-5 and H2O-1) were able to inhibit 65, 70 and 97.5% of the 40 strains studied here respectively. Clear zones of inhibition were observed when H2O-1 was tested against SRB-containing consortium T6-lab and Desulfovibrio alaskensis strain NCIMB 13491, while strain T6-5 was able to inhibit only the D. alaskensis strain. The three substances showed to be insensitive to different enzymes and chemicals, were heat stable and the substances produced by strains T6-5 and H2O-1 were active over a wide pH range. Three different AMS produced by Bacillus strains from an oil reservoir, two of them with activity against SRB, are presented here. The preliminary characterization of these AMS points to their potential use as biocides in the petroleum industry for controlling problems associated with SRB.

Resolving the chemical structures of off-odorants and potentially harmful substances in toys-example of children's swords.

Science.gov (United States)

Denk, Philipp; Velasco-Schön, Cristina; Buettner, Andrea

2017-09-01

Most children's toys on the market are primarily made out of plastic and other complex composite materials. Consumer complaints about offensive odors or irritating effects associated with toy products have increased in recent years. One example is the strongly perceivable negative odor reported for a particular series of toy swords. Characterizing the presence of contaminants, including those that have the potential to be deleterious to health, in such products is a significant analytical challenge due to the high baseline abundance of chemical constituents of the materials used in the products. In the present study, the nature of offensive odorants associated with toy sword products was examined by gas chromatography (GC). After initial sensory evaluations, the volatile compounds from the toy products were recovered using solvent extraction and solvent-assisted flavor evaporation. The extracts were analyzed using GC-olfactometry (GC-O) and two-dimensional GC-O coupled with mass spectrometry (GC-GC-MS/O). A total of 26 odor-active compounds, including aromatic hydrocarbons and phenols, were identified among numerous non-odorous volatile by-products. These substances also included polycyclic aromatic hydrocarbons, which were analyzed by GC-MS. Representative substances were naphthalene and 1,2-dihydronaphthalene that exhibited moldy, mothball-like odor impressions, and phenol derivatives with leather-like, phenolic, horse-stable-like smells. The odorants detected correlated with the assigned attributes from the sensory analyses. This study clearly shows that the detection and identification of such odorous contaminants can provide key indications of potentially harmful yet unknown substances in everyday products such as toys. Graphical abstract ᅟ.

Online test purchased new psychoactive substances in 5 different European countries: A snapshot study of chemical composition and price.

Science.gov (United States)

Brunt, Tibor Markus; Atkinson, Amanda Marie; Nefau, Thomas; Martinez, Magali; Lahaie, Emmanuel; Malzcewski, Artur; Pazitny, Martin; Belackova, Vendula; Brandt, Simon D

2017-06-01

New psychoactive substances (NPS) are on offer worldwide online, in order to shed light on the purity and price of these substances in the European Union, a research collaboration was set up involving France, United Kingdom (UK), the Netherlands, Czech Republic and Poland. Per country, around 10 different NPS were test purchased from different webshops. Then, chemical analysis of NPS was done with according reference standards to identify and quantify the contents. In contrast to what is generally advertised on the webshops (>99%), purity varied considerably per test purchased NPS. Several NPS were mislabelled, some containing chemical analogues (e.g. 25B/C-NBOMe instead of 25I-NBOMe, pentedrone instead of 3,4-DMMC). But in some cases NPS differed substantially from what was advertised (e.g. pentedrone instead of AMT or 3-FMC instead of 5-MeO-DALT). Per gram, purity-adjusted prices of cathinones differed substantially between three countries of test purchase, with Poland being the least expensive. Synthetic cannabinoids were relatively the most expensive in the Czech Republic and least expensive in the UK. The current findings provides a snapshot of the price and chemical contents of NPS products purchased by different countries and in different webshops. There is a potential danger of mislabelling of NPS. The great variety in price and purity of the delivered products might be the result of the market dynamics of supply and demand and the role of law enforcement in different European countries. Copyright © 2017 Elsevier B.V. All rights reserved.

Toward a comprehensive approach to the collection and analysis of pica substances, with emphasis on geophagic materials.

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Sera L Young

2008-09-01

Full Text Available Pica, the craving and subsequent consumption of non-food substances such as earth, charcoal, and raw starch, has been an enigma for more than 2000 years. Currently, there are little available data for testing major hypotheses about pica because of methodological limitations and lack of attention to the problem.In this paper we critically review procedures and guidelines for interviews and sample collection that are appropriate for a wide variety of pica substances. In addition, we outline methodologies for the physical, mineralogical, and chemical characterization of these substances, with particular focus on geophagic soils and clays. Many of these methods are standard procedures in anthropological, soil, or nutritional sciences, but have rarely or never been applied to the study of pica.Physical properties of geophagic materials including color, particle size distribution, consistency and dispersion/flocculation (coagulation should be assessed by appropriate methods. Quantitative mineralogical analyses by X-ray diffraction should be made on bulk material as well as on separated clay fractions, and the various clay minerals should be characterized by a variety of supplementary tests. Concentrations of minerals should be determined using X-ray fluorescence for non-food substances and inductively coupled plasma-atomic emission spectroscopy for food-like substances. pH, salt content, cation exchange capacity, organic carbon content and labile forms of iron oxide should also be determined. Finally, analyses relating to biological interactions are recommended, including determination of the bioavailability of nutrients and other bioactive components from pica substances, as well as their detoxification capacities and parasitological profiles.This is the first review of appropriate methodologies for the study of human pica. The comprehensive and multi-disciplinary approach to the collection and analysis of pica substances detailed here is a necessary

Chemical properties of peat used in balneology

Science.gov (United States)

Szajdak, L.; Hładoń, T.

2009-04-01

significantly on the genesis of peatlands and the depth of sampling. The chemical properties of peat fulvic acids (FA) have some genetic peculiarities due to the specific conditions of the process of humification of peat-forming plants in mires. The process of humification in mires takes place in the top-forming layer under amphibious moisture conditions. Substances of microbial origin are water-soluble and can participate in the formation of peat FA to a little extent. So a main source of structural units for the peat HA and FA is suggested to be organic constituents of peat forming plants of various botanical composition. The content of aromatic units in peat FA was shown to depend on the content of lignin in peat-forming plants and also of the aromatization of polysaccharides mainly due to the transformation of cellulose. FA characterized lower than humic acids molecular weight (1000-30,000). FA's are composed of a series of highly oxidized aromatic rings with a large number of side chains. Building blocks are benzene carboxylic acids and phenolic acids. These are held together by hydrogen bonding van der Waals' forces and ionic bonding. FA contains larger concentrations of nitrogen. This fraction also contains a great deal of polysaccharide materials, as well as low molecular fatty acids and cytoplasmic constituents of microorganisms. These compounds are linear, flexible colloids at low concentrations, and spherical colloids at high solution concentrations and low pH values. A more adequate knowledge of the chemical structure of humic materials will assist us in better understanding the physiological effects and also the function of these macromolecules on the health that these materials are know to exert. This improved knowledge provides us better information on chemical structure of humic substances from peats, which are responsible for pharmacotherapeutic, pharmacokinetic and biopharmaceutical effect. This structure of FA creates proper conditions for uptake of nutrient

Tourette syndrome and excitatory substances: is there a connection?

Science.gov (United States)

Zou, Li-Ping; Wang, Ying; Zhang, Li-Ping; Zhao, Jian-Bo; Lu, Jin-Fang; Liu, Qun; Wang, Hang-Yan

2011-05-01

The objective of this study is to investigate the relationship between excitatory substances by testing the urine in children with Tourette syndrome (TS). We performed a control study involving 44 patients with TS and 44 normal children by investigating the children's daily eating habits. We used the gas chromatograph-mass spectrometer and liquid chromatograph-mass spectrometer from Agilent. Substances for detection included 197 excitatory substances prohibited by the International Olympic Committee and other substances with similar chemical structures or biological functions for urine samples. Forty-four patients who did not take any drugs in the past 2 weeks enrolled in the study. The positive rate in the experiment group was three cases, while it was negative in the control group. The level of 1-testosterone increased in one extremely severe TS patient who ate large amounts of puffed food and drank an average of 350 ml of cola per day. Cathine and other substances with similar chemical constitution or similar biological effects increased in one severe TS patient who ate bags of instant noodles daily, according to the high score of the Yale Global Tic Severity Scale. An increase in ephedrine type, testosterone, and stimulants may be related to the pathogenesis of TS. Unhealthy food possibly causes TS. The relationship between excitatory substances and TS needs to be explored with the goal of providing more information on diagnosing and treating TS.

The dilemma in prioritizing chemicals for environmental analysis: known versus unknown hazards.

Science.gov (United States)

Anna, Sobek; Sofia, Bejgarn; Christina, Rudén; Magnus, Breitholtz

2016-08-10

A major challenge for society is to manage the risks posed by the many chemicals continuously emitted to the environment. All chemicals in production and use cannot be monitored and science-based strategies for prioritization are essential. In this study we review available data to investigate which substances are included in environmental monitoring programs and published research studies reporting analyses of chemicals in Baltic Sea fish between 2000 and 2012. Our aim is to contribute to the discussion of priority settings in environmental chemical monitoring and research, which is closely linked to chemical management. In total, 105 different substances or substance groups were analyzed in Baltic Sea fish. Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were the most studied substances or substance groups. The majority, 87%, of all analyses comprised 20% of the substances or substance groups, whereas 46 substance groups (44%) were analyzed only once. Almost three quarters of all analyses regarded a POP-substance (persistent organic pollutant). These results demonstrate that the majority of analyses on environmental contaminants in Baltic Sea fish concern a small number of already regulated chemicals. Legacy pollutants such as POPs pose a high risk to the Baltic Sea due to their hazardous properties. Yet, there may be a risk that prioritizations for chemical analyses are biased based on the knowns of the past. Such biases may lead to society failing in identifying risks posed by yet unknown hazardous chemicals. Alternative and complementary ways to identify priority chemicals are needed. More transparent communication between risk assessments performed as part of the risk assessment process within REACH and monitoring programs, and information on chemicals contained in consumer articles, would offer ways to identify chemicals for environmental analysis.

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

International Nuclear Information System (INIS)

Bell, J.E.; Leone, A.; Bell, E.T.

1986-01-01

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 14 C 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

Identification of the pH sensor and activation by chemical modification of the ClC-2G Cl- channel.

Science.gov (United States)

Stroffekova, K; Kupert, E Y; Malinowska, D H; Cuppoletti, J

1998-10-01

Rabbit and human ClC-2G Cl- channels are voltage sensitive and activated by protein kinase A and low extracellular pH. The objective of the present study was to investigate the mechanism involved in acid activation of the ClC-2G Cl- channel and to determine which amino acid residues play a role in this acid activation. Channel open probability (Po) at +/-80 mV holding potentials increased fourfold in a concentration-dependent manner with extracellular H+ concentration (that is, extracellular pH, pHtrans), with an apparent acidic dissociation constant of pH 4.95 +/- 0.27. 1-Ethyl-3(3-dimethylaminopropyl)carbodiimide-catalyzed amidation of the channel with glycine methyl ester increased Po threefold at pHtrans 7.4, at which the channel normally exhibits low Po. With extracellular pH reduction (protonation) or amidation, increased Po was due to a significant increase in open time constants and a significant decrease in closed time constants of the channel gating, and this effect was insensitive to applied voltage. With the use of site-directed mutagenesis, the extracellular region EELE (amino acids 416-419) was identified as the pH sensor and amino acid Glu-419 was found to play the key or predominant role in activation of the ClC-2G Cl- channel by extracellular acid.

Matriptase autoactivation is tightly regulated by the cellular chemical environments.

Directory of Open Access Journals (Sweden)

Jehng-Kang Wang

Full Text Available The ability of cells to rapidly detect and react to alterations in their chemical environment, such as pH, ionic strength and redox potential, is essential for cell function and survival. We present here evidence that cells can respond to such environmental alterations by rapid induction of matriptase autoactivation. Specifically, we show that matriptase autoactivation can occur spontaneously at physiological pH, and is significantly enhanced by acidic pH, both in a cell-free system and in living cells. The acid-accelerated autoactivation can be attenuated by chloride, a property that may be part of a safety mechanism to prevent unregulated matriptase autoactivation. Additionally, the thio-redox balance of the environment also modulates matriptase autoactivation. Using the cell-free system, we show that matriptase autoactivation is suppressed by cytosolic reductive factors, with this cytosolic suppression being reverted by the addition of oxidizing agents. In living cells, we observed rapid induction of matriptase autoactivation upon exposure to toxic metal ions known to induce oxidative stress, including CoCl2 and CdCl2. The metal-induced matriptase autoactivation is suppressed by N-acetylcysteine, supporting the putative role of altered cellular redox state in metal induced matriptase autoactivation. Furthermore, matriptase knockdown rendered cells more susceptible to CdCl2-induced cell death compared to control cells. This observation implies that the metal-induced matriptase autoactivation confers cells with the ability to survive exposure to toxic metals and/or oxidative stress. Our results suggest that matriptase can act as a cellular sensor of the chemical environment of the cell that allows the cell to respond to and protect itself from changes in the chemical milieu.

Adsorption of cadmium by activated carbon cloth: influence of surface oxidation and solution pH.

Science.gov (United States)

Rangel-Mendez, J R; Streat, M

2002-03-01

The surface of activated carbon cloth (ACC), based on polyacrylonitrile fibre as a precursor, was oxidised using nitric acid, ozone and electrochemical oxidation to enhance cadmium ion exchange capacity. Modified adsorbents were physically and chemically characterised by pH titration, direct titration, X-ray photoelectron spectroscopy, elemental analysis, surface area and porosimetry, and scanning electron microscopy. BET surface area decreased after oxidation, however, the total ion exchange capacity increased by a factor of approximately 3.5 compared to the commercial as-received ACC. A very significant increase in cadmium uptake, by a factor of 13, was observed for the electrochemically oxidised ACC. Equilibrium sorption isotherms were determined at pH 4, 5 and 6 and these showed that cadmium uptake increased with increasing pH. There was clear evidence of physical damage to ozone-oxidised fibre, however, acid and electrochemically oxidised samples were completely stable.

pH Dependent Studies of Chemical Bath Deposition Grown ZnO-SiO{sub 2} Core-Shell Thin Films

Energy Technology Data Exchange (ETDEWEB)

Seth, Rajni; Panwar, Sanjay [Maharishi Markandeshwar University, Ambala (India); Kumar, Sunil; Kang, T. W.; Jeon, H. C. [Dongguk University, Seoul (Korea, Republic of)

2017-01-15

ZnO-SiO{sub 2} core-shell thin films were synthesized using chemical-bath deposition at different pH. Optical studies were done to optimize the thin films to find suitable parameters for solar cell buffer layers. These studies were done by measuring the transmission at 500 nm, which is the peak of the solar spectrum. All the parameters were seen to be highly pH dependent. The transmittance for a sample synthesized with a pH of 10.8 reached 85%. The transmittance was found not to depend on the bandgap values, but it was found possibly to depend on the fewer defect states created at a particular pH, as shown by Urbach energy and scanning electron microscopy (SEM) surface structure. An appreciable transmittance was observed in the blue region of the spectrum which had been missing until now in commercial CdS-based buffer layers. The Fourier-transform infrared and the energy dispersive X-ray spectra confirmed that the films were composed of only ZnO and silica only : no impurities were found. The urbach energy values and the SEM image of sample S3 clearly indicate the creation of fewer of defects, leading to higher crystallintiy and higher transmittance. Therefore, this shortcoming can be resolved by the substituted buffer layer of ZnO:SiO{sub 2} nano-composite thin film, which can enhance the blue response of the photovoltaic cells.

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

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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.

3-Nitropropionic acid production by the endophytic Diaporthe citri: Molecular taxonomy, chemical characterization, and quantification under pH variation.

Science.gov (United States)

Polonio, Julio Cesar; Ribeiro, Marcos Alessandro Dos Santos; Rhoden, Sandro Augusto; Sarragiotto, Maria Helena; Azevedo, João Lúcio; Pamphile, João Alencar

2016-12-01

3-nitropropionic acid (3-NPA) is a nitrogenated compound produced by plants and fungi and has been associated with poisoning episodes in humans, animals, and to induction of Huntington disease symptoms in rats. The production of 3-NPA by endophytes has been reported, but the function and biosynthesis are not well-defined. The specie of endophytic strain G-01 was confirmed as Diaporthe citri using a multilocus sequence analysis, and was verified different concentrations of 3-NPA produced at different initial pHs by these strain. The chemical analysis indicated that 3-NPA was the majority compound present in the crude extracts. The better extraction condition was at an initial pH of 7.0 for 22 d, yielding about 80 % of 3-NPA per mg of extract. It was observed that the concentration of 3-NPA increased after the initial consumption of reduction sugars, indicating that the compound is produced after the high energetic production phase of the fungus. These and other studies demonstrate the production of this compound by plants and endophytic fungi, indicating that 3-NPA may be involved in defence and nutrition systems of endophytes and host plants, and they also might participate in the biogeochemical nitrogen cycle. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Amperometric micro pH measurements in oxygenated saliva.

Science.gov (United States)

Chaisiwamongkhol, Korbua; Batchelor-McAuley, Christopher; Compton, Richard G

2017-07-24

An amperometric micro pH sensor has been developed based on the chemical oxidation of carbon fibre surfaces (diameter of 9 μm and length of ca. 1 mm) to enhance the population of surface quinone groups for the measurement of salivary pH. The pH analysis utilises the electrochemically reversible two-electron, two-proton behaviour of surface quinone groups on the micro-wire electrodes. A Nernstian response is observed across the pH range 2-8 which is the pH range of many biological fluids. We highlight the measurement of pH in small volumes of biological fluids without the need for oxygen removal and specifically the micro pH electrode is examined by measuring the pH of commercial synthetic saliva and authentic human saliva samples. The results correspond well with those obtained by using commercial glass pH electrodes on large volume samples.

Herbivore-plant interactions: mixed-function oxidases and secondary plant substances.

Science.gov (United States)

Brattsten, L B; Wilkinson, C F; Eisner, T

1977-06-17

The mixed-function oxidases of a polyphagous insect larva (the southern armyworm, Spodoptera eridania) were found to be induced by a diversity of secondary plant substances. The induction proceeds rapidly and in response to a small quantity of secondary substance. Following induction, the larva is less susceptible to dietary poisoning. It is argued that mixed-function oxidases play a major role in protecting herbivores against chemical stress from secondary plant substances.

Optimization of Cultural Conditions for Production of Extracellular Polymeric Substances (EPS) by Serpentine Rhizobacterium Cupriavidus pauculus KPS 201

OpenAIRE

Arundhati Pal; A. K. Paul

2013-01-01

Extracellular polymeric substances (EPS) are complex biopolymers produced by a wide array of microorganisms for protection against dessication, aggregation, adhesion, and expression of virulence. Growth associated production of EPS by Ni-resistant Cupriavidus pauculus KPS 201 was determined in batch culture using sodium gluconate as the sole carbon source. The optimum pH and temperature for EPS production were 6.5 and 25°C, respectively. Optimal EPS yield (118 μg/mL) was attained at 0.35% Na-...

Manipulating and Monitoring On-Surface Biological Reactions by Light-Triggered Local pH Alterations.

Science.gov (United States)

Peretz-Soroka, Hagit; Pevzner, Alexander; Davidi, Guy; Naddaka, Vladimir; Kwiat, Moria; Huppert, Dan; Patolsky, Fernando

2015-07-08

Significant research efforts have been dedicated to the integration of biological species with electronic elements to yield smart bioelectronic devices. The integration of DNA, proteins, and whole living cells and tissues with electronic devices has been developed into numerous intriguing applications. In particular, the quantitative detection of biological species and monitoring of biological processes are both critical to numerous areas of medical and life sciences. Nevertheless, most current approaches merely focus on the "monitoring" of chemical processes taking place on the sensing surfaces, and little efforts have been invested in the conception of sensitive devices that can simultaneously "control" and "monitor" chemical and biological reactions by the application of on-surface reversible stimuli. Here, we demonstrate the light-controlled fine modulation of surface pH by the use of photoactive molecularly modified nanomaterials. Through the use of nanowire-based FET devices, we showed the capability of modulating the on-surface pH, by intensity-controlled light stimulus. This allowed us simultaneously and locally to control and monitor pH-sensitive biological reactions on the nanodevices surfaces, such as the local activation and inhibition of proteolytic enzymatic processes, as well as dissociation of antigen-antibody binding interactions. The demonstrated capability of locally modulating the on-surface effective pH, by a light stimuli, may be further applied in the local control of on-surface DNA hybridization/dehybridization processes, activation or inhibition of living cells processes, local switching of cellular function, local photoactivation of neuronal networks with single cell resolution and so forth.

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). L'action de solutions d'uranylcarbonates de Li, Na, K, Mg, Ca sur

[Effects of soil pH on the competitive uptake of amino acids by maize and microorganisms].

Science.gov (United States)

Ma, Qing Xu; Wang, Jun; Cao, Xiao Chuang; Sun, Yan; Sun, Tao; Wu, Liang Huan

2017-07-18

Organic nitrogen can play an important role in plant growth, and soil pH changed greatly due to the over-use of chemical fertilizers, but the effects of soil pH on the competitive uptake of amino acids by plants and rhizosphere microorganisms are lack of detailed research. To study the effects of soil pH on the uptake of amino acids by maize and soil microorganisms, two soils from Hangzhou and Tieling were selected, and the soil pH was changed by the electrokinesis, then the 15 N-labeled glycine was injected to the centrifuge tube with a short-term uptake of 4 h. Soil pH had a significant effect on the shoot and root biomass, and the optimal pH for maize shoot growth was 6.48 for Hangzhou red soil, while it was 7.65 for Tieling brown soil. For Hangzhou soil, the 15 N abundance of maize shoots under pH=6.48 was significantly higher than under other treatments, and the uptake amount of 15 N-glycine was also much higher. However, the 15 N abundance of maize shoots and roots under pH=7.65 Tieling soil was significantly lower than it under pH=5.78, but the uptake amount of 15 N-glycine under pH=7.65 was much higher. The microbial biomass C was much higher in pH=6.48 Hangzhou soil, while it was much lower in pH=7.65 Tieling soil. According to the results of root uptake, root to shoot transportation, and the competition with microorganisms, we suggested that although facing the fierce competition with microorganisms, the maize grown in pH=6.48 Hangzhou soil increased the uptake of glycine by increasing its root uptake and root to shoot transportation. While in pH=7.65 Tieling soil, the activity of microorganisms was decreased, which decreased the competition with maize for glycine, and increased the uptake of glycine by maize.

Effects of K3[Fe(CN)6] slurry's pH value and applied potential on tungsten removal rate for chemical-mechanical planarization application

Energy Technology Data Exchange (ETDEWEB)

Akonko, S.B.; Li, D.Y.; Ziomek-Moroz, M.; Hawk, J.A.; Miller, A.; Cadien, K.

2005-07-01

Chemical-mechanical planarization (CMP) is an important process for building multilevel interconnections for electronic devices. Directly planarizing tungsten, which is used as via or contact in microelectronic circuits, by wear is a difficult process because of its high hardness. Therefore, an effective approach has been developed to facilitate planarizing tungsten surface by removing a continuously growing passive film on tungsten when exposed to a low-pH potassium ferricyanide slurry. Since the passive film is softer than tungsten, this chemical mechanical planarization process is effective. In this work, in order to determine effects of corrosion and wear on tungsten removal rate, attempts were made to investigate corrosion, wear, and corrosive wear behavior of tungsten in K3[Fe(CN)6] slurries. Electrochemical and tribological experiments were carried out for different slurry pH values and potentials using a rotating pin-on-disc tribometer. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize surface films formed at the different pH levels and potentials. It was demonstrated that the tungsten removal rate increased with increasing slurry pH and potential. Mechanisms involved are discussed.

The National Library of Medicine's (NLM) Hazardous Substances Data Bank (HSDB): background, recent enhancements and future plans.

Science.gov (United States)

Fonger, George Charles; Hakkinen, Pertti; Jordan, Shannon; Publicker, Stephanie

2014-11-05

The National Library of Medicine's (NLM) Division of Specialized Information Services (SIS) Toxicology and Environmental Health Information Program is responsible for the management of the online Hazardous Substances Data Bank (HSDB). HSDB, a part of NLM's Toxicology Data Network (TOXNET(®)), is a file of chemical/substance information with one record for each specific chemical or substance, or for a category of chemicals or substances. Like the rest of TOXNET's databases and other resources, HSDB is available online at no cost to global users. HSDB has approximately 5600 chemicals and substances, with a focus on toxicology information and also on human exposure, industrial hygiene, emergency handling procedures, environmental fate, regulatory requirements, and related areas of likely interest to HSDB users. All data are from a core set of books, government documents, technical reports, selected primary journal literature, and other online sources of information, with a goal of linking the HSDB content to as much publicly available information as possible. HSDB's content is peer-reviewed by the Scientific Review Panel, a group of experts in the areas covering the scope of HSDB content. Recent enhancements include the addition of chemical structures to HSDB records, the addition of new subfields such as age groups for human data, more occupational exposure standards, and the addition of information on numerous nanomaterials. Examples of future plans include providing more exposure-related information, e.g., uses of a chemical or substance in consumer products; the addition of information summaries aimed towards consumers and other members of the public wanting to learn about a chemical or substance; more visual content such as diagrams (images) of the pathways of metabolism of a substance; and enhanced search features and navigation. Published by Elsevier Ireland Ltd.

Screening of chemical substances ; Application of the Uniform System for the Evaluation of Substances, USES 1.0

NARCIS (Netherlands)

Gingnagel P; Vermeire TG; ACT

1995-01-01

Priority setting is a sequential process and can be regarded a first step in the risk management of substances. It is used to extract, from the many thousands of substances, those that are expected to be the most riskful to man and the environment and therefore deserve the highest attention from

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

2016-02-05

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

Radiation treatment of refractory substances in wastewater for recycling water

International Nuclear Information System (INIS)

Sekiguchi, Masayuki; Tanabe, Hiroko; Sawai, Teruko

1997-01-01

The refractory substances such as molasses pigments and lignin in sewage interfere with recycle system from the secondary effluents from sewage sludge plants, so we investigated the effects of radiation treatment on these substances in sewage. The dialyzed molasses pigments in the wastewater, discharged from baker's yeast factory were easily decomposed and decolorized. When the artificial sewage sample, containing lignin, fumic acid and tannic acid, was irradiated with gamma rays, the TOC was reduced to one-half of its initial value at 10 kGy, and then the pH dropped to near the minimum value. On the other hand, the pH and TOC of sewage influent sample were little affected by gamma ray irradiation. However, the increases of organic acid formation by gamma rays irradiation were observed for both samples: oxalic acid for the artificial sewage sample, and the formic acid and lactic acid for sewage influent sample were produced at lower absorbed doses, respectively. (author)

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.

Elimination of micropollutants and hazardous substances at the source in the chemical and pharmaceutical industry.

Science.gov (United States)

Blöcher, C

2007-01-01

Industrial wastewater, especially from chemical and pharmaceutical production, often contains substances that need to be eliminated before being discharged into a biological treatment plant and following water bodies. This can be done within the production itself, in selected waste water streams or in a central treatment plant. Each of these approaches has certain advantages and disadvantages. Furthermore, a variety of wastewater treatment processes exist that can be applied at each stage, making it a challenging task to choose the best one in economic and ecological terms. In this work a general approach for that and examples from practice are discussed.

The symbolic language of substances and molecules: noise or ...

African Journals Online (AJOL)

Most substances are given names and formulae based upon knowledge of their molecules. However for substances most commonly met in elementary chemistry courses, especially inorganic substances, this is often not the case. The potential noise is amplified further when dealing with chemical reaction equations.

Psychiatric Consultation and Substance Use Disorders

Directory of Open Access Journals (Sweden)

Sheila Specker

2009-01-01

Full Text Available Background A substantial number of patients in general hospitals will evince substance abuse problems but a majority is unlikely to be adequately identified in the referral-consultation process. This failure may preclude patients from receiving effective interventions for substance use disorders. Objectives 1. To evaluate all referred patients for possible substance use disorders. 2. To ascertain the degree of convergence between patients referred for chemical problems and the corresponding DSM diagnosis. 3. To compare demographic data for substance abusing patients and referrals not so classified. 4. To evaluate conditions concomitant with substance use disorders. Method Consecutive one-year referrals (524 to consultation-liaison psychiatric services were scrutinized for chemically-related problems by psychiatric consultants. Results Of the referrals, 176 met criteria for substance use disorders (SUD (57% alcohol; 25% other drugs; 18% both alcohol and other drugs. Persons diagnosed with SUD tended to be younger, male, non-Caucasian, unmarried, and unemployed. They were more likely to be depressed, have liver and other gastrointestinal problems, and to have experienced traumatic events; they also tended to have current financial difficulties. Most were referred for SUD evaluation by personnel in general medicine and family practice. Following psychiatric consultation, SUD designated patients were referred mainly to substance abuse treatment programs. The only variable related to recommended inpatient versus outpatient services for individuals with SUD was the Global Assessment of Functioning Axis (GAF with persons having lower estimated functioning more likely to be referred for inpatient interventions. Conclusions These data are similar to the results of past studies in this area. Unlike previous investigations in the domain of consultative-liaison psychiatry, financial stressors and specific consultant recommendations were included in data

Psychiatric Consultation and Substance Use Disorders

Directory of Open Access Journals (Sweden)

Sheila Specker

2009-11-01

Full Text Available Background: A substantial number of patients in general hospitals will evince substance abuse problems but a majority is unlikely to be adequately identified in the referral-consultation process. This failure may preclude patients from receiving effective interventions for substance use disorders. Objectives: 1. To evaluate all referred patients for possible substance use disorders. 2. To ascertain the degree of convergence between patients referred for chemical problems and the corresponding DSM diagnosis. 3. To compare demographic data for substance abusing patients and referrals not so classified. 4. To evaluate conditions concomitant with substance use disorders. Method: Consecutive one-year referrals (524 to consultation-liaison psychiatric services were scrutinized for chemically-related problems by psychiatric consultants. Results: Of the referrals, 176 met criteria for substance use disorders (SUD (57% alcohol; 25% other drugs; 18% both alcohol and other drugs. Persons diagnosed with SUD tended to be younger, male, non-Caucasian, unmarried, and unemployed. They were more likely to be depressed, have liver and other gastrointestinal problems, and to have experienced traumatic events; they also tended to have current financial difficulties. Most were referred for SUD evaluation by personnel in general medicine and family practice. Following psychiatric consultation, SUD designated patients were referred mainly to substance abuse treatment programs. The only variable related to recommended inpatient versus outpatient services for individuals with SUD was the Global Assessment of Functioning Axis (GAF with persons having lower estimated functioning more likely to be referred for inpatient interventions. Conclusions: These data are similar to the results of past studies in this area. Unlike previous investigations in the domain of consultative-liaison psychiatry, financial stressors and specific consultant recommendations were included in

Low corrosive chemical decontamination method using pH control. 1. Basic system

International Nuclear Information System (INIS)

Nagase, Makoto; Ishida, Kazushige; Uetake, Naohito; Anazawa, Kazumi; Nakamura, Fumito; Yoshikawa, Hiroo; Tamagawa, Tadashi; Furukawa, Kiyoharu

2001-01-01

A new low corrosive decontamination method was developed which uses both oxalic acid and hydrazine as the reducing agent and potassium permanganate as the oxidizing agent. Less corrosion of structural materials during the decontamination is realized by pH control of the reducing agent. The pH of 2.5, attained by adding hydrazine to oxalic acid, was the optimum pH for maintaining a high decontamination effect and lowering the corrosion at the same time. As this reducing agent can be decomposed into carbon dioxide, nitrogen and water by using a catalyst column with hydrogen peroxide, the amount of secondary radioactive waste is small. These good features were demonstrated through actual plant decontamination tasks. (author)

46 CFR Appendix B to Subpart C to... - Substance Technical Guidelines, Benzene

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Substance Technical Guidelines, Benzene B Appendix B to... Subpart C to Part 197—Substance Technical Guidelines, Benzene I. Physical and Chemical Data (a) Substance... temperature: 580 °C (1076 °F). (3) Flammable limits in air, % by volume: Lower: 1.3%, Upper: 7.5%. (4...

High acidity tolerance in lichens with fumarprotocetraric, perlatolic or thamnolic acids is correlated with low pK{sub a1} values of these lichen substances

Energy Technology Data Exchange (ETDEWEB)

Hauck, Markus, E-mail: mhauck@gwdg.d [Albrecht von Haller Institute of Plant Sciences, Dept. Plant Ecology, University of Goettingen, Untere Karspuele 2, D-37073 Goettingen (Germany); Juergens, Sascha-Rene [Albrecht von Haller Institute of Plant Sciences, Dept. Plant Ecology, University of Goettingen, Untere Karspuele 2, D-37073 Goettingen (Germany); Huneck, Siegfried [Fliederweg 34a, D-06179 Langenbogen, Saalkreis (Germany); Leuschner, Christoph [Albrecht von Haller Institute of Plant Sciences, Dept. Plant Ecology, University of Goettingen, Untere Karspuele 2, D-37073 Goettingen (Germany)

2009-10-15

The depsidone fumarprotocetraric acid as well as the depsides perlatolic and thamnolic acids are lichen secondary metabolites. Their first dissociation constants (pK{sub a1}) in methanol were determined to be 2.7 for perlatolic acid and 2.8 for fumarprotocetraric and thamnolic acids by UV spectroscopy. Lower pK{sub a1} values are, so far, not known from lichen substances. Several lichens producing at least one of these compounds are known for their outstanding tolerance to acidic air pollution. This is demonstrated by evaluating published pH preferences for central European lichens. The low pK{sub a1} values suggest that strong dissociation of the studied lichen substances is a prerequisite for the occurrence of lichens with these compounds on very acidic substrata, as protonated lichen substances of different chemical groups, but not their conjugated bases, are known to shuttle protons into the cytoplasm and thereby apparently damage lichens. - Depsides and depsidones with low pK{sub a1} values occur in highly acidity-tolerant lichens.

Wearable, Flexible, and Multifunctional Healthcare Device with an ISFET Chemical Sensor for Simultaneous Sweat pH and Skin Temperature Monitoring.

Science.gov (United States)

Nakata, Shogo; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

2017-03-24

Real-time daily healthcare monitoring may increase the chances of predicting and diagnosing diseases in their early stages which, currently, occurs most frequently during medical check-ups. Next-generation noninvasive healthcare devices, such as flexible multifunctional sensor sheets designed to be worn on skin, are considered to be highly suitable candidates for continuous real-time health monitoring. For healthcare applications, acquiring data on the chemical state of the body, alongside physical characteristics such as body temperature and activity, are extremely important for predicting and identifying potential health conditions. To record these data, in this study, we developed a wearable, flexible sweat chemical sensor sheet for pH measurement, consisting of an ion-sensitive field-effect transistor (ISFET) integrated with a flexible temperature sensor: we intend to use this device as the foundation of a fully integrated, wearable healthcare patch in the future. After characterizing the performance, mechanical flexibility, and stability of the sensor, real-time measurements of sweat pH and skin temperature are successfully conducted through skin contact. This flexible integrated device has the potential to be developed into a chemical sensor for sweat for applications in healthcare and sports.

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

Annealing Temperature Dependence of ZnO Nanostructures Grown by Facile Chemical Bath Deposition for EGFET pH Sensors

Science.gov (United States)

Bazilah Rosli, Aimi; Awang, Zaiki; Sobihana Shariffudin, Shafinaz; Herman, Sukreen Hana

2018-03-01

Zinc Oxide (ZnO) nanostructures were deposited using chemical bath deposition (CBD) technique in water bath at 95 °C for 4 h. Post-deposition heat treatment in air ambient at various temperature ranging from 200-600 °C for 30 min was applied in order to enhance the electrical properties of ZnO nanostructures as the sensing membrane of extended-gate field effect transistor (EGFET) pH sensor. The as-deposited sample was prepared for comparison. The samples were characterized in terms of physical and sensing properties. FESEM images showed that scattered ZnO nanorods were formed for the as-deposited sample, and the morphology of the ZnO nanorods changed to ZnO nanoflowers when the heat treatment was applied from 200-600 °C. For sensing properties, the samples heated at 300 °C showed the higher sensitivity which was 39.9 mV/pH with the linearity of 0.9792. The sensing properties was increased with the increasing annealing treatment temperature up to 300 °C before decreased drastically.

pH : a key control of the nature and distribution of dissolved organic matter and associated trace metals in soil

Science.gov (United States)

Pédrot, M.; Dia, A.; Davranche, M.

2009-04-01

Dissolved organic matter is ubiquitous at the Earth's surface and plays a prominent role in controlling metal speciation and mobility from soils to hydrosystems. Humic substances (HS) are usually considered to be the most reactive fraction of organic matter. Humic substances are relatively small and formed by chemically diverse organic molecules, bearing different functional groups that act as binding sites for cations and mineral surfaces. Among the different environmental physicochemical parameters controlling the metal speciation, pH is likely to be the most important one. Indeed, pH affect the dissociation of functional groups, and thus can influence the HS structure, their ability to complex metals, their solubility degree allowing the formation of aggregates at the mineral surface. In this context, soil/water interactions conducted through batch system experiments, were carried out with a wetland organic-rich soil to investigate the effect of pH on the release of dissolved organic carbon (DOC) and associated trace elements. The pH was regulated between 4 and 7.5 using an automatic pH stat titrator. Ultrafiltration experiments were performed to separate the dissolved organic pool following decreasing pore sizes (30 kDa, 5 kDa and 2 kDa with 1 Da = 1 g.mol-1). The pH increase induced a significant DOC release, especially in heavy organic molecules (size >5 kDa) with a high aromaticity (>30 %). These were probably humic acids (HA). This HA release influenced (i) directly the trace element concentrations in soil solution since HA were enriched in several trace elements such as Th, REE, Y, U, Cr and Cu; and (ii) indirectly by the breaking of clay-humic complexes releasing Fe- and Al-rich nanoparticles associated with V, Pb and Ti. By contrast, at acid pH, most HS were complexed onto mineral surfaces. They also sequestered iron nanoparticles. Therefore, at low pH, most part of DOC molecules had a size pH and ionic strength .The molecular size and shape of HS is

Dissociation and metal-binding characteristics of yellow lichen substances suggest a relationship with site preferences of lichens.

Science.gov (United States)

Hauck, Markus; Jürgens, Sascha-René; Willenbruch, Karen; Huneck, Siegfried; Leuschner, Christoph

2009-01-01

Many species of lichen-forming fungi contain yellow or orange extracellular pigments belonging to the dibenzofurans (usnic acid), anthraquinones (e.g. parietin) or pulvinic acid group. These pigments are all equally efficient light screens, leading us to question the potential ecological and evolutionary significance of diversity in yellow and orange lichen substances. Here the hypothesis is tested that the different pigments differ in metal-binding characteristics, which suggest that they may contribute to adaptation to sites differing in pH and metal availability. UV spectroscopy was used to study the dissociation and the pH dependence of the metal-binding behaviour of seven isolated lichen substances in methanol. Metals applied were selected macro- and micro-nutrients (Cu(2+), Fe(2+), Fe(3+), Mg(2+), Mn(2+) and Zn(2+)). All the pigments studied are strong to moderate acids with pK(a1) values between 2.8 and 4.5. Metal complexation is common in the lichen substances studied. Complexation takes place under acidic conditions with usnic acid, but under alkaline conditions with parietin and most compounds of the pulvinic acid group. The pulvinic acid derivative rhizocarpic acid forms metal complexes both in the acidic and the alkaline range. Metal complexation by lichen substances could be a prerequisite for lichen substance-mediated control of metal uptake. Assuming such an effect at pH values where the affinity of the metal for the lichen substance is intermediate would explain the strong preference of lichens with usnic or rhizocarpic acids to acidic substrata. Moreover, it would explain the preference of lichens with parietin and some lichens with compounds of the pulvinic acid group either for nutrient-rich substrata at low pH or for calcareous substrata.

Evidence of Non-local Chemical, Thermal and Gravitational Effects

Directory of Open Access Journals (Sweden)

Hu H.

2007-04-01

Full Text Available Quantum entanglement is ubiquitous in the microscopic world and manifests itself macroscopically under some circumstances. But common belief is that it alone cannot be used to transmit information nor could it be used to produce macroscopic non- local effects. Yet we have recently found evidence of non-local effects of chemical substances on the brain produced through it. While our reported results are under independent verifications by other groups, we report here our experimental findings of non-local chemical, thermal and gravitational effects in simple physical systems such as reservoirs of water quantum-entangled with water being manipulated in a remote reservoir. With the aids of high-precision instruments, we have found that the pH value, temperature and gravity of water in the detecting reservoirs can be non-locally affected through manipulating water in the remote reservoir. In particular, the pH value changes in the same direction as that being manipulated; the temperature can change against that of local environment; and the gravity apparently can also change against local gravity. These non-local effects are all reproducible and can be used for non-local signalling and many other purposes. We suggest that they are mediated by quantum entanglement between nuclear and/or electron spins in treated water and discuss the implications of these results.

A new approach to pH of point of zero charge measurement: crystal-face specificity by scanning force microscopy (SFM)

Science.gov (United States)

Eggleston, Carrick M.; Jordan, Guntram

1998-06-01

The pH of point of zero charge (pH pzc) is a fundamentally important property used in modeling the interaction of solid surfaces with aqueous solutions and solutes. The pH pzc is normally measured by acid-base titration of solid suspensions. Here, a scanning force microscope (SFM) is used to measure forces of repulsion or attraction between chemically tailored tips and quartz (101) and hematite (001) surfaces, as a function of tip-surface separation and pH. The force at contact (FAC) is at a minimum near the expected point of pH pzc for a chemically similar tip and sample. The results are compared to predicted interaction forces from a simple DLVO model, which shows that the SFM technique for pH pzc measurement is most promising for surfaces (such as iron oxides) that have not-too-widely spaced pK a1 and pK a2 values for surface site deprotonation. However, improvements in precision will be necessary to fully utilize the technique. The SFM approach to pH pzc measurement may in future allow the measurement of crystal-face-specific pH pzc, rather than a weighted average of all exposed surface sites, and thus allow us to ask better-defined structure-reactivity questions for mineral surfaces. The approach can in theory be extended to the single-site scale in order to probe the properties (e.g., potential and charge) of individual terrace, step, or kink sites.

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

Treatment outcomes for substance abuse among adolescents with learning disorders.

Science.gov (United States)

Yu, Jennifer W; Buka, Stephen L; Fitzmaurice, Garrett M; McCormick, Marie C

2006-07-01

This paper assesses whether chemically dependent adolescents with comorbid learning disorders (LDs) derived less effective treatment results when compared to chemically dependent adolescents without LD and examines the moderating effects of prior treatments, treatment length, and treatment completion. Two hundred one adolescents were recruited between 1992 and 1993 from Massachusetts residential treatment centers and subsequently followed up 6 months after enrollment. Compared to chemically dependent teenagers without LD, those with LD were twice as likely to re-use substances at least once by follow-up. LD teenagers were more likely to attend Alcoholics/Narcotics Anonymous if they had prior admissions to treatment programs and longer treatment length. LD teenagers who completed treatment also experienced a greater decrease in current depression compared to LD teenagers not completing the treatment. This study is the first to consider outcomes of substance abuse treatment for adolescents with LD and contributes to the growing literature on comorbidity and substance abuse treatment.

Supported Nanosized α-FeOOH Improves Efficiency of Photoelectro-Fenton Process with Reaction-Controlled pH Adjustment for Sustainable Water Treatment

Directory of Open Access Journals (Sweden)

Chuan Wang

2012-01-01

Full Text Available The overall photoelectro-Fenton (PE-Fenton process for water treatment with neutral initial pH includes three steps of pH reduction, PE-Fenton reaction, and pH elevation. Reaction-controlled pH adjustment (RCpA, which utilizes the intrinsic electrochemical reactions instead of chemical addition, has been employed to lower the pH, maintain the lowered pH for the Fenton reaction, and recover the pH for final effluent discharge. This study demonstrated that the overall efficiency of this sustainable PE-Fenton process was improved by rapidly recycling the iron substance. Nanosized iron oxide was prepared and employed to ensure such rapid recycling. SEM and XRD results showed that the as-prepared iron oxide was α-FeOOH with 20 nm in size. The experimental results of dimethyl phthalate (DMP degradation showed that diatomite-supported α-FeOOH (N-α-FeOOH/diatomite could efficiently reduce the DMP concentration and total organic carbon. Furthermore, compared with Fe3+, the N-α-FeOOH/diatomite saved 160 min for iron settlement at 20 mg L−1 DMP concentration. Also, with the increment in the initial DMP concentration, extra energy consumed by the individual step of PE-Fenton reaction using the N-α-FeOOH/diatomite became negligible compared with that using free iron ions with the increment in the initial DMP concentration. This development is expected to be a major step of the PE-Fenton process with RCpA towards actual water treatment.

Cadmium and Zn availability as affected by pH manipulation and its assessment by soil extraction, DGT and indicator plants

International Nuclear Information System (INIS)

Muhammad, Iqbal; Puschenreiter, Markus; Wenzel, Walter W.

2012-01-01

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 soln ) and 0.005 M Ca(NO 3 ) 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 soln , the 0.005 M Ca(NO 3 ) 2 -soluble fractions and the DGT-measured Cd and Zn concentrations (C 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 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 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: ► 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

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

**1**5N-NMR INVESTIGATION OF HYDROXYLAMINE DERIVATIZED HUMIC SUBSTANCES.

Science.gov (United States)

Thorn, Kevin A.; Arterburn, Jeffrey B.; Mikita, Michael A.

1986-01-01

Humic substances are the most abundant naturally occurring refactory organic compounds in soils and water. They have a broad range of physical, chemical and physiological properties. In soils, humic substances contribute to the cation exchange capacity, help maintain the physical structure, and play a role in plant growth and nutrition. In aquatic systems, humic substances serve to regulate the levels of inorganic constituents, yield trihalomethanes upon chlorination, and transport or concentrate organic and inorganic pollutants. The oxygen containing functional groups of humic and fulvic acids are believed to play a key role in the chemical properties of humic substances. This study was undertaken to gain additional information on the specific types of oxygen functionalities in humic substances. Since the analysis of hydroxyl moieties had been earlier established, we focused our attention on the analysis of ketone and aldehyde functional groups in humic substances.

Biosynthesis of schwertmannite by Acidithiobacillus ferrooxidans cell suspensions under different pH condition

Energy Technology Data Exchange (ETDEWEB)

Liao Yuehua [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Zhou Lixiang [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)], E-mail: lxzhou@njau.edu.cn; Liang Jianru; Xiong Huixin [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)

2009-01-01

Oxidation of FeSO{sub 4} solution with initial pH in the range of 1.40-3.51 by Acidithiobacillus ferrooxidans LX5 cell at 26 deg. C and subsequent precipitation of resulting Fe(III) were investigated in the present study. Results showed that the oxidation rate of Fe(II) was around 1.2-3.9 mmol l{sup -1} h{sup -1}. X-ray diffraction (XRD) indicated that the formed precipitates were composed of natrojarosite with schwertmannite when the initial pH was 3.51, while only schwertmannite was produced when initial pH was in the range of 1.60-3.44 and no precipitate occurred when initial pH {<=} 1.40. Scanning electron microscope (SEM) analyses showed that precipitates formed in solution with initial pH 3.51 were spherical particles of about 0.4 {mu}m in diameter and had a smooth surface, whereas precipitates in solution with initial pH {<=} 3.44 were spherical particles of approximately 1.0 {mu}m in diameter, having specific sea-urchin morphology. Specific surface area of the precipitates varied from 3.42 to 23.45 m{sup 2} g{sup -1}. X-ray fluorescence analyses revealed that schwertmannite formed in solution with initial pH in the range of 2.00-3.44 had similar elemental composition and could be expressed as Fe{sub 8}O{sub 8}(OH){sub 4.42}(SO{sub 4}){sub 1.79,} whereas Fe{sub 8}O{sub 8}(OH){sub 4.36}(SO{sub 4}){sub 1.82} and Fe{sub 8}O{sub 8}(OH){sub 4.29}(SO{sub 4}){sub 1.86} as its chemical formula when the initial pH was 1.80 and 1.60, respectively.

Competitive adsorption of heavy metal by extracellular polymeric substances (EPS) extracted from sulfate reducing bacteria.

Science.gov (United States)

Wang, Jin; Li, Qing; Li, Ming-Ming; Chen, Tian-Hu; Zhou, Yue-Fei; Yue, Zheng-Bo

2014-07-01

Competitive adsorption of heavy metals by extracellular polymeric substances (EPS) extracted from Desulfovibrio desulfuricans was investigated. Chemical analysis showed that different EPS compositions had different capacities for the adsorption of heavy metals which was investigated using Cu(2+) and Zn(2+). Batch adsorption tests indicated that EPS had a higher combined ability with Zn(2+) than Cu(2+). This was confirmed and explained by Fourier transform infrared (FTIR) and excitation-emission matrix (EEM) spectroscopy analysis. FTIR analysis showed that both polysaccharides and protein combined with Zn(2+) while only protein combined with Cu(2+). EEM spectra further revealed that tryptophan-like substances were the main compositions reacted with the heavy metals. Moreover, Zn(2+) had a higher fluorescence quenching ability than Cu(2+). Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical mechanism of D-amino acid oxidase from Rhodotorula gracilis: pH dependence of kinetic parameters.

Science.gov (United States)

Ramón, F; Castillón, M; De La Mata, I; Acebal, C

1998-01-01

The variation of kinetic parameters of d-amino acid oxidase from Rhodotorula gracilis with pH was used to gain information about the chemical mechanism of the oxidation of D-amino acids catalysed by this flavoenzyme. d-Alanine was the substrate used. The pH dependence of Vmax and Vmax/Km for alanine as substrate showed that a group with a pK value of 6.26-7.95 (pK1) must be unprotonated and a group with a pK of 10.8-9.90 (pK2) must be protonated for activity. The lower pK value corresponded to a group on the enzyme involved in catalysis and whose protonation state was not important for binding. The higher pK value was assumed to be the amino group of the substrate. Profiles of pKi for D-aspartate as competitive inhibitor showed that binding is prevented when a group on the enzyme with a pK value of 8.4 becomes unprotonated; this basic group was not detected in Vmax/Km profiles suggesting its involvement in binding of the beta-carboxylic group of the inhibitor. PMID:9461524

From proton nuclear magnetic resonance spectra to pH. Assessment of {sup 1}H NMR pH indicator compound set for deuterium oxide solutions

Energy Technology Data Exchange (ETDEWEB)

Tynkkynen, Tuulia, E-mail: tuulia.tynkkynen@uku.fi [Laboratory of Chemistry, Department of Biosciences, University of Kuopio, PO Box 1627, 70211 Kuopio (Finland); Tiainen, Mika; Soininen, Pasi; Laatikainen, Reino [Laboratory of Chemistry, Department of Biosciences, University of Kuopio, PO Box 1627, 70211 Kuopio (Finland)

2009-08-19

In this study, a protocol for pH determination from D{sub 2}O samples using {sup 1}H NMR pH indicator compounds was developed and assessed by exploring the pH-dependency of 13 compounds giving pH-dependent {sup 1}H NMR signals. The indicators cover the pH range from pH* 0 to 7.2. Equations to transform the indicator chemical shifts to pH estimates are given here for acetic acid, formic acid, chloroacetic acid, dichloroacetic acid, creatine, creatinine, glycine, histidine, 1,2,4-triazole, and TSP (2,2,3,3-tetradeutero-3-(trimethylsilyl)-propionic acid). To characterize the method in presence of typical solutes, the effects of common metabolites, albumin and ionic strength were also evaluated. For the ionic strengths, the effects were also modelled. The experiments showed that the use of pH sensitive {sup 1}H NMR chemical shifts allows the pH determination of typical metabolite solutions with accuracy of 0.01-0.05 pH units. Also, when the ionic strength is known with accuracy better than 0.1 mol dm{sup -3} and the solute concentrations are low, pH{sub nmr}{sup *} (the NMR estimate of pH) can be assumed to be within 0.05 pH units from potentiometrically determined pH.

Random coil chemical shift for intrinsically disordered proteins

DEFF Research Database (Denmark)

Kjærgaard, Magnus; Brander, Søren; Poulsen, Flemming Martin

2011-01-01

. Temperature has a non-negligible effect on the (13)C random coil chemical shifts, so temperature coefficients are reported for the random coil chemical shifts to allow extrapolation to other temperatures. The pH dependence of the histidine random coil chemical shifts is investigated in a titration series......, which allows the accurate random coil chemical shifts to be obtained at any pH. By correcting the random coil chemical shifts for the effects of temperature and pH, systematic biases of the secondary chemical shifts are minimized, which will improve the reliability of detection of transient secondary...

ESTIMATION OF INDUSTRIAL WASTE SAFETY BY THE “CHEMICAL OXYGEN DEMAND” INDEX

Directory of Open Access Journals (Sweden)

A. S. Kayshev

2015-01-01

Full Text Available One of the indices of industrial waste safety including distillers grains is chemical oxygen demand (COD, and its value (53591÷64184 mg O/dm3 shows that it can be considered as unsustainable waste. This high value of COD is conditioned by the absence of toxins in distillers grains, and by concentration of biologically active substances after which isolation the distillers grains index lowers by 74%. This allows considering the distillers grains as environmentally safe. The results received evidence the necessity for consideration of COD index only as an index of oxidized substances, but not the criteria of waste pollution.

Substance abuse in anaesthetists.

Science.gov (United States)

Garcia-Guasch, Roser; Roigé, Jaume; Padrós, Jaume

2012-04-01

Anaesthesiologists have a significantly higher frequency of substance abuse by a factor of nearly 3 when compared with other physicians. This is still a current problem that must be reviewed. Many hypotheses have been formulated to explain why anaesthesiologists appear to be more susceptible to substance abuse than other medical professionals (genetic differences in sensitivity to opioids, stress, the association between chemical dependence and other psychopathology or the second-hand exposure hypothesis). Environmental exposure and sensitization may be an important risk factor in physician addiction. There is a long debate about returning to work for an anaesthetist who has been depending on opioid drugs, and recent debates are discussed. Institutional efforts have been made in many countries and physician health programmes have been developed. As drug abuse among anaesthesiologists has continued, new studies have been conducted to know the theories about susceptibility. Written substance abuse policies and controls must be taken in place and in all countries.

Impact of humic substances and nitrogen fertilising on the fruit quality and yield of custard apple

Directory of Open Access Journals (Sweden)

Marcelo dos Santos Cunha

2014-09-01

Full Text Available The custard apple (Annona squamosa L., also known as the sugar apple, is a fruit species native to Brazil that has been poorly studied, especially in relation to the effect of humic substances on its fruit quality and yield. An experiment was conducted from December 2010 to November 2011 to evaluate the fruit quality and yield of the custard apple as a function of nitrogen fertilising and the use of humic substances. The experimental design consisted of randomised blocks, with treatments distributed in a factorial arrangement (4 x 2, using four nitrogen doses (0, 100, 175 and 250 g of N plant-1 and two humic substance applications (with and without humic substances, with four replications. The fruit yield and fruit characteristics, such as fruit mass, titratable acidity (TA, soluble solids (SS, pulp pH and SS/TA ratio, were recorded. The humic substances and the nitrogen levels significantly affected the soluble solids, titratable acidity and SS/TA ratio, while the pH pulp was only influenced by the humic substances. The humic substances promoted a quantitative increase in the fruit yield of 0.63 ton ha-1. The fruit quality and yield of the custard apple depend on the nitrogen fertiliser and the interaction of the humic substances. Nitrogen fertilising of 100 g per plant, associated with humic substances, could be recommended for use in the production of custard apples.

Isolation and identification of an allelopathic substance from Hibiscus sabdariffa.

Science.gov (United States)

Suwitchayanon, Prapaipit; Pukclai, Piyatida; Ohno, Osamu; Suenaga, Kiyotake; Kato-Noguchi, Hisashi

2015-05-01

In this study, an allelopathic substance was isolated from an aqueous methanol extract of Hibiscus sabdariffa L. by column chromatography and reverse phase HPLC. The chemical structure of the substance was determined by 1H NMR spectroscopy and mass spectrometry as trimethyl allo-hydroxycitrate. Trimethyl allo-hydroxycitrate inhibited the growth of cress hypocotyls and roots at concentrations greater than 10 mM. The concentrations required for 50% growth inhibition of the hypocotyls and roots of cress were 20.3 and 14.4 mM, respectively. The inhibitory activity of trimethyl allo-hydroxycitrate suggests that the substance may act as an allelopathic substance of H. sabdariffa.

Olefins and chemical regulation in Europe: REACH.

Science.gov (United States)

Penman, Mike; Banton, Marcy; Erler, Steffen; Moore, Nigel; Semmler, Klaus

2015-11-05

REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) is the European Union's chemical regulation for the management of risk to human health and the environment (European Chemicals Agency, 2006). This regulation entered into force in June 2007 and required manufacturers and importers to register substances produced in annual quantities of 1000 tonnes or more by December 2010, with further deadlines for lower tonnages in 2013 and 2018. Depending on the type of registration, required information included the substance's identification, the hazards of the substance, the potential exposure arising from the manufacture or import, the identified uses of the substance, and the operational conditions and risk management measures applied or recommended to downstream users. Among the content developed to support this information were Derived No-Effect Levels or Derived Minimal Effect Levels (DNELs/DMELs) for human health hazard assessment, Predicted No Effect Concentrations (PNECs) for environmental hazard assessment, and exposure scenarios for exposure and risk assessment. Once registered, substances may undergo evaluation by the European Chemicals Agency (ECHA) or Member State authorities and be subject to requests for additional information or testing as well as additional risk reduction measures. To manage the REACH registration and related activities for the European olefins and aromatics industry, the Lower Olefins and Aromatics REACH Consortium was formed in 2008 with administrative and technical support provided by Penman Consulting. A total of 135 substances are managed by this group including 26 individual chemical registrations (e.g. benzene, 1,3-butadiene) and 13 categories consisting of 5-26 substances. This presentation will describe the content of selected registrations prepared for 2010 in addition to the significant post-2010 activities. Beyond REACH, content of the registrations may also be relevant to other European activities, for

Mapping student thinking in chemical synthesis

Science.gov (United States)

Weinrich, Melissa

In order to support the development of learning progressions about central ideas and practices in different disciplines, we need detailed analyses of the implicit assumptions and reasoning strategies that guide students' thinking at different educational levels. In the particular case of chemistry, understanding how new chemical substances are produced (chemical synthesis) is of critical importance. Thus, we have used a qualitative research approach based on individual interviews with first semester general chemistry students (n = 16), second semester organic chemistry students (n = 15), advanced undergraduates (n = 9), first year graduate students (n = 15), and PhD candidates (n = 16) to better characterize diverse students' underlying cognitive elements (conceptual modes and modes of reasoning) when thinking about chemical synthesis. Our results reveal a great variability in the cognitive resources and strategies used by students with different levels of training in the discipline to make decisions, particularly at intermediate levels of expertise. The specific nature of the task had a strong influence on the conceptual sophistication and mode of reasoning that students exhibited. Nevertheless, our data analysis has allowed us to identify common modes of reasoning and assumptions that seem to guide students' thinking at different educational levels. Our results should facilitate the development of learning progressions that help improve chemistry instruction, curriculum, and assessment.

Psychoactive substance use by truck drivers: a systematic review.

Science.gov (United States)

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

2014-01-01

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 out in countries with large land areas and 23 obtained their information through self-reporting. The most frequently studied substances were alcohol (n=25), amphetamines (n=17), marijuana (n=16) and cocaine (n=13). The prevalence of the use of these substances greatly varied: alcohol (0.1-91.0%); amphetamines (0.2-82.5%), marijuana (0.2-29.9%), cocaine (0.1-8.3%). The frequency of substance use was lower in studies that investigated the presence of these substances in biological samples than in those based on self-reported use. In 12 studies that evaluated factors associated with the intake of psychoactive substances, the following stood out: younger age, higher income, longer trips, alcohol consumption, driving in the night shift, travelling interstate routes, long or short sleep, fewer hours of rest, little experience of the driver, connection with small and medium sized companies, income below levels determined by labour agreements, productivity-based earnings and prior involvement in accidents. The frequency of psychoactive substance use by truck drivers seems to be high, although that greatly varies according to the type of substance and the method of collecting the information. The use of these substances was mainly associated with indicators of poor working conditions.

chemical safety and chemical security overview

African Journals Online (AJOL)

IICBA01

Wafaa M. Abdou. Chemical Industries Division, National Research Centre, ... substances to attain an acceptably low risk of exposure. Security is: ... Sharing locations of chemicals can publicize targets for theft .... D. Personal Protective Equipments (PPE): ... E. Lighting & Noise Levels ... PPE. ➢ Autoclave or sterilize wastes.

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.

Cross-linked self-assembled micelle based nanosensor for intracellular pH measurements

DEFF Research Database (Denmark)

Ek, Pramod Kumar; Søndergaard, Rikke Vicki; Windschiegl, Barbara

2014-01-01

A micelle based nanosensor was synthesized and investigated as a ratiometric pH sensor for use in measurements in living cells by fluorescent microscopy. The nanosensor synthesis was based on self-assembly of an amphiphilic triblock copolymer, which was chemically cross-linked after micelle......-linked by an amidation reaction using 3,6,9-trioxaundecandioic acid cross-linker. The cross-linked micelle was functionalized with two pH sensitive fluorophores and one reference fluorophore, which resulted in a highly uniform ratiometric pH nanosensor with a diameter of 29 nm. The use of two sensor fluorophores...... provided a sensor with a very broad measurement range that seems to be influenced by the chemical design of the sensor. Cell experiments show that the sensor is capable of monitoring the pH distributions in HeLa cells....

Chemical Composition and Labeling of Substances Marketed as Selective Androgen Receptor Modulators and Sold via the Internet.

Science.gov (United States)

Van Wagoner, Ryan M; Eichner, Amy; Bhasin, Shalender; Deuster, Patricia A; Eichner, Daniel

2017-11-28

Recent reports have described the increasing use of nonsteroidal selective androgen receptor modulators, which have not been approved by the US Food and Drug Administration (FDA), to enhance appearance and performance. The composition and purity of such products is not known. To determine the chemical identity and the amounts of ingredients in dietary supplements and products marketed and sold through the internet as selective androgen receptor modulators and compare the analyzed contents with product labels. Web-based searches were performed from February 18, 2016, to March 25, 2016, using the Google search engine on the Chrome and Internet Explorer web browsers to identify suppliers selling selective androgen receptor modulators. The products were purchased and the identities of the compounds and their amounts were determined from April to August 2016 using chain-of-custody and World Anti-Doping Association-approved analytical procedures. Analytical findings were compared against the label information. Products marketed and sold as selective androgen receptor modulators. Chemical identities and the amount of ingredients in each product marketed and sold as selective androgen receptor modulators. Among 44 products marketed and sold as selective androgen receptor modulators, only 23 (52%) contained 1 or more selective androgen receptor modulators (Ostarine, LGD-4033, or Andarine). An additional 17 products (39%) contained another unapproved drug, including the growth hormone secretagogue ibutamoren, the peroxisome proliferator-activated receptor-δ agonist GW501516, and the Rev-ErbA agonist SR9009. Of the 44 tested products, no active compound was detected in 4 (9%) and substances not listed on the label were contained in 11 (25%). In only 18 of the 44 products (41%), the amount of active compound in the product matched that listed on the label. The amount of the compounds listed on the label differed substantially from that found by analysis in 26 of 44 products

Labelling of natural humic substances with {sup 14}C and their use in adsorption studies

Energy Technology Data Exchange (ETDEWEB)

Mansel, A.; Kupsch, H. [Institut fuer Interdisziplinaere Isotopenforschung, Permoserstr. 15, D-04318 Leipzig (Germany)

2005-07-01

Full text of publication follows: The reactive carbon compounds (humic substances, HS) of the dissolved organic matter (DOC) dominate the spreading of inorganic and organic pollutants in the bio-geosphere. The classical analytical methods such as TOC-detection and UV-spectroscopy are of limited use in the lower concentration range (< 1 mg/l), usually found in environmental samples. Based on our promising results of the HS radiolabelling with [{sup 14}C]phenyl-diazonium ions, we applied these radiolabelled substances first time to sorption studies under conditions, usually found in subterranean waste repositories. The natural HS (humic acid HA, fulvic acid FA) were purified by the IHSS-procedure. Aldrich-HA (AHA), Gorleben-HA (GoHy-573), an aquatic HA (HS3), a terrestrial HA (HS4), a lignite HA (HAL), an aquatic FA (FS3) and Gorleben-FA (GoHy-573) were used for our investigations. A synthetic HA (M42) was provided by the Forschungszentrum Rossendorf / Germany [1]. The radiolabelled HS were contacted in aqueous solution with a sandy soil (pH 5.0), granite (pH 6.0), diabase (pH 8.0) and kaolinite (pH 4.7) in batch experiments under conditions near to nature. Adsorption isotherms of various radiolabelled humic acids were determined depending on geo-material, pH, HS concentration, contact time and heavy metal content. The behaviour of the radiolabelled HS was not influenced by the labelling procedure as demonstrated by the adsorption experiments. With the use of radiolabelled humic substances a concentration range below mg/l can be studied. [1] Determination and Comparison of Uranyl Complexation Constants with Natural and Model Humic Acids. S. Pompe, A. Brachmann, M. Bubner, G. Geipel, K. H. Heise, G. Bernhard and H. Nitsche Radiochim. Acta 82, 89 (1998). (authors)

Humic substances in ground waters

International Nuclear Information System (INIS)

Paxeus, N.; Allard, B.; Olofsson, U.; Bengtsson, M.

1986-01-01

The presence of naturally occurring complexing agents that may enhance the migration of disposed radionuclikes and thus facilitate their uptake by plantsis a problem associated with the underground disposal of radioactive wastes in bedrock. The main purpose of this work is to characterized humic substances from ground water and compare them with humic substances from surface water. The humic materials isolated from ground waters of a borehole in Fjaellveden (Sweden) were characterized by elemental and functional group analyses. Spectroscopic properties, molecular weight distributions as well as acid-base properties of the fulvic and humic fractions were also studied. The ground water humic substances were found to be quite similar in many respects (but not identical) to the Swedish surface water humics concentrated from the Goeta River but appeared to be quite different from the American ground water humics from Biscayne Florida Aquifer or Laramie Fox-Hills in Colorado. The physico-chemical properties of the isolated humic materials are discussed

Low temperature synthesis of nanocrystalline lanthanum monoaluminate powders by chemical coprecipitation

Energy Technology Data Exchange (ETDEWEB)

Kuo, C.-L. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Wang, C.-L. [Department of Materials Science and Engineering, I-Shou University, 1 Section 1, Hsueh-Cheng Road, Ta-Hsu Hsiang, Kaohsiung 840, Taiwan (China); Chen, T.-Y. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Chen, G.-J. [Department of Materials Science and Engineering, I-Shou University, 1 Section 1, Hsueh-Cheng Road, Ta-Hsu Hsiang, Kaohsiung 840, Taiwan (China); Hung, I-M. [Department of Chemical Engineering and Materials Science, Yuan Ze University, 135 Yuan-Tung Road, Chungli, Taoyuan 320, Taiwan (China); Shih, C.-J. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shi-Chuan 1st Road, Kaohsiung 807, Taiwan (China)]. E-mail: CJShih@kmu.edu.tw; Fung, K.-Z. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China)

2007-08-16

Nanocrystalline lanthanum monoaluminate (LaAlO{sub 3}) powders were prepared by chemical coprecipitation using 25 vol.% of NH{sub 4}OH, 0.05 M La(NO{sub 3}){sub 3}.6H{sub 2}O and 0.05 M Al(NO{sub 3}){sub 3}.9H{sub 2}O aqueous solutions as the starting materials. Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analyses (TGA/DTA), X-ray diffraction (XRD), Raman spectrometry, specific surface area (BET) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) were utilized to characterize the LaAlO{sub 3} powders prepared by chemical coprecipitation. The crystallization temperature of the LaAlO{sub 3} precursor gels precipitated at pH 9 is estimated as 810 deg. C by TG/DTA. The XRD pattern of the LaAlO{sub 3} precursor gels precipitated at pH 8-12 and calcined at 700 deg. C for 6 h shows a broad arciform continuum exist between 24{sup o} and 32{sup o} and sharp peaks of LaAlO{sub 3} except the precursor gels precipitated at pH 9. For the LaAlO{sub 3} precursor gels precipitated at pH 9 and calcined at 700 deg. C for 6 h, the formation of the perovskite LaAlO{sub 3} phase occurs and the presence of crystalline impurities is not found. The crystallite size of LaAlO{sub 3} slightly increases from 37.8 to 41.5 nm with calcination temperature increasing from 700 to 900 deg. C for 6 h. The LaAlO{sub 3} powders prepared by chemical coprecipitation have a considerably large specific surface of 30 m{sup 2}/g. The relative density greater than 97% is obtained when these nanocrystalline LaAlO{sub 3} powders are sintered at 1550 deg. C for 2 h.

Chemical composition of sublates (difficultly soluble substances) which form on interaction of polyvalent metal ions with potassium alkylcarboxylate

International Nuclear Information System (INIS)

Skrylev, L.D.; Skryleva, T.L.; Sazonova, V.F.

1996-01-01

The pH value is considered for its effect on chemical composition of sublates which form on interaction of fatty acid collectors (potassium alkylcarboxylate) with polyvalent ions of Ni, An, Cu and Be. It is shown that interaction of these ions with fatty acid collectors in weakly acid, neutral and weakly alkaline solutions is accompanied by formation of medium soaps. Acid soaps are formed in more acid solutions, while in more alkaline-basic soaps. Domains of stability for medium soaps of Ni, Zn, Cu and Be are determined. 17 refs.; 4 figs

Characterization of an organ-specific differentiator substance

International Nuclear Information System (INIS)

Steele, V.E.

1975-01-01

The objectives of this research are to characterize a diffusible brain inhibitory substance, to elucidate its role in the maintenance of anterior-posterior polarity during head or tail regeneration, and to utilize its action in measuring the differentiative integrity of the stem cells following x-irradiation. Crude, cell-free homogenates of whole planarians (Dugesia etrusca) were centrifuged, Millipore filtered, ultrafiltered using Dow Hollow Fibers, chromatographed using Sephadex and Bio-Gel gel filtration media, electrophoresed using a continuous flow paper electrophoresis apparatus, digested by various enzymatic procedures, and ion focused using LKB Ampholine Electrofocusing equipment. The activities of the various fractions were assayed by placing decapitated planarians in the fractions, then, after nine days the resultant regenerated brain volumes were measured. In order to measure the effect that this substance has on the post-irradiation survival of both the whole animal and the differentiative integrity of the stem cells, x-irradiated planarians were decapitated and allowed to regenerate with or without addition of the inhibitory substance. The inhibitory activity is destroyed when the extract is treated with Pronase, but remains unaffected when treated with RNase, DNase, or Lipase. The inhibitory substance migrates toward the positive electrode when electrophoresed, and has an isoelectric point of between pH 4.75 and 5.38 when isoelectrically focused

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

Science.gov (United States)

2012-07-23

... Pigment Manufacturers Association (CPMA) members with similar products, there is no substantiation of... the PMN substances have been incorporated into a polymer, glass, dispersion, cementitious matrix, or a.... Specifically, the PMN substances are intended to replace pigments containing heavy metals such as lead and...

Chemically triggered ejection of membrane tubules controlled by intermonolayer friction.

Science.gov (United States)

Fournier, J-B; Khalifat, N; Puff, N; Angelova, M I

2009-01-09

We report a chemically driven membrane shape instability that triggers the ejection of a tubule growing exponentially toward a chemical source. The instability is initiated by a dilation of the exposed monolayer, which is coupled to the membrane spontaneous curvature and slowed down by intermonolayer friction. Our experiments are performed by local delivery of a basic pH solution to a giant vesicle. Quantitative fits of the data give an intermonolayer friction coefficient b approximately 2x10;{9} J s/m;{4}. The exponential growth of the tubule may be explained by a Marangoni stress yielding a pulling force proportional to its length.

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)

Heikola, Tiina; Vuorinen, Ulla; Kumpulainen, Sirpa; Kiviranta, Leena; Korkeakoski, Petri

2012-01-01

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 CaCl 2 , and trace amounts of SiO 2 , K, Br, Mg and SO 4 . 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

Critical review of pH sensing with optical fibers

Science.gov (United States)

Baldini, Francesco

1999-02-01

The chemical parameter most investigated with optical fibers is doubtless pH. The first pH optical fiber sensor was described in 1980. Since then, more than one hundred and twenty original papers describing different pH sensors have been published, based on absorption-based indicators on fluorophores. Such interest is perfectly justified, since pH detection is essential in many fields of application, ranging from the environment and medicine to industry and process control. Moreover, pH transduction can be used for measuring different chemical species, such as carbon dioxide, ammonia and pesticides. Notwithstanding the great number of prototypes realized in different laboratories all over the world, only a few products are available on the market. A critical analysis of the state of art in pH sensing using optical fibers is described, outlining the advantages and disadvantages of an optical approach.

Extraction and characterization of bound extracellular polymeric substances from cultured pure cyanobacterium (Microcystis wesenbergii).

Science.gov (United States)

Liu, Lizhen; Qin, Boqiang; Zhang, Yunlin; Zhu, Guangwei; Gao, Guang; Huang, Qi; Yao, Xin

2014-08-01

Preliminary characterization of bound extracellular polymeric substances (bEPS) of cyanobacteria is crucial to obtain a better understanding of the formation mechanism of cyanobacterial bloom. However, the characterization of bEPS can be affected by extraction methods. Five sets (including the control) of bEPS from Microcystis extracted by different methods were characterized using three-dimensional excitation and emission matrix (3DEEM) fluorescence spectroscopy combined chemical spectrophotometry; and the characterization results of bEPS samples were further compared. The agents used for extraction were NaOH, pure water and phosphate buffered saline (PBS) containing cationic exchange resins, and hot water. Extraction methods affected the fluorescence signals and intensities in the bEPS. Five fluorescence peaks were observed in the excitation and emission matrix fluorescence spectra of bEPS samples. Two peaks (peaks T₁ and T₂) present in all extractions were identified as protein-like fluorophores, two (peaks A and C) as humic-like fluorophores, and one (peak E) as a fulvic-like substance. Among these substances, the humic-like and fulvic-like fluorescences were only seen in the bEPS extracted with hot water. Also, NaOH solution extraction could result in strong fluorescence intensities compared to the other extraction methods. It was suggested that NaOH at pH10.0 was the most appropriate method to extract bEPS from Microcystis. In addition, dialysis could affect the yields and characteristics of extracted bEPS during the determination process. These results will help us to explore the issues of cyanobacterial blooms. Copyright © 2014. Published by Elsevier B.V.

Eye irritancy screening for classification of chemicals.

Science.gov (United States)

van Erp, Y H; Weterings, P J

1990-01-01

A screening method was applied to determine the eye irritation potential of industrial chemicals. Bovine eyes (BE) were used to predict corneal damage and chicken egg chorioallantoic membranes (CAM) to estimate the irritancy potential of chemical substances towards the conjunctivae. Exposure of the BE to a test substance is followed by grading of the corneal opacity and epithelial injury. The CAM is inspected for signs of capillary injection, haemorrhages and coagulation. The tests are collectively called the BECAM assay. So far, almost 150 substances have been evaluated in this test system. A good correlation was observed between the BECAM assay and in vivo data; less than 5% of chemicals showed a clear disagreement. Also the assay is promising for labelling requirements according to the EEC criteria.

Chemical risk factors responsible for the formation of wedge-shaped lesions

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Perić Dejan

2015-01-01

Full Text Available Introduction: Non-carious tooth substances loss pose a major health problem of a modern man. The literature often collectively describes all non-carious lesions and is therefore difficult to compare results obtained by different authors. Chemical factors are one of the predisposing factors responsible for the formation of wedge-shaped erosions. Aim: Examination of chemical risk factors as one of the predisposing causes responsible for the formation of wedge-shaped lesions. Method: We examined 62 patients with wedge-shaped erosions (mean age 45.52 ± 12.03 years, 58.1% of men and 60 patients without erosions in the control group (mean age 34.40 ± 9.28 years, 60% men . The entire examination was completed by using a questionnaire at the Dental Clinic of the University of Pristina - Kosovska Mitrovica. salivary pH was measured by the pH meter. Results: The results show that the wedge-shaped lesions often occur equally in both men and women. Considerably often it might appear in older people but can also occur in teenagers. Patients with wedge-shaped erosion have increased acidity of saliva, a heightened sense of acid in the mouth and consume a lot more carbonated drinks compared to patients without erosions. Conclusion: Wedge-shaped lesions are more common in people older than 40 years. Taking into account the results obtained in this study it can be concluded that the chemical risk factors truly fall within the predisposing factors that may be responsible for the creation of wedge-shaped erosions.

Traceability of pH to the Mole

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Maria Filomena Camões

2015-08-01

Full Text Available Free acidity of aqueous solutions was initially defined in 1909 by Søren Peter Lauritz Sørensen as pH = −lgcH+ (c/mol·dm−3 or m/mol·kg−1 of the free hydrogen ions in solution, H+ soon (1910 was changed to pH = paH+ = −lgaH+, integrating the new concepts of activity, ai and activity coefficient γi, for the ionic species i under concern, H+ in this case; it is ai = −lg(miγi. Since individual ions do not exist alone in solution, primary pH values cannot be assigned solely by experimental measurements, requiring extra thermodynamic model assumptions for the activity coefficient, γH+, which has put pH in a unique situation of not being fully traceable to the International System of Units (SI. Also the concept of activity is often not felt to be as perceptible as that of concentration which may present difficulties, namely with the interpretation of data. pH measurements on unknown samples rely on calibration of the measuring setup with adequate reference pH buffers. In this work, the assignment of pH values to buffers closely matching the samples, e.g., seawater, is revisited. An approach is presented to assess the quantity pmH+ = −lgmH+ profiting from the fact that, contrary to single ion activity coefficients, mean activity coefficients,   can be assessed based on experimentally assessed quantities alone, γExp ±, thus ensuring traceability to the mole, the SI base unit for amount of substance. Compatibility between γExp ± and mean activity coefficient calculated by means of Pitzer model equations, γPtz ±, validates the model for its intended use.

Control of electron transfer in the cytochrome system of mitochondria by pH, transmembrane pH gradient and electrical potential. The cytochromes b-c segment.

Science.gov (United States)

Papa, S; Lorusso, M; Izzo, G; Capuano, F

1981-02-15

1. A study is presented of the effects of pH, transmembrane pH gradient and electrical potential on oxidoreductions of b and c cytochromes in ox heart mitochondria and 'inside-out' submitochondrial particles. 2. Kinetic analysis shows that, in mitochondria at neutral pH, there is a restraint on the aerobic oxidation of cytochrome b566 with respect to cytochrome b562. Valinomycin plus K+ accelerates cytochrome b566 oxidation and retards net oxidation of cytochrome b562. At alkaline pH the rate of cytochrome b566 oxidation approaches that of cytochrome b562 and the effects of valinomycin on b cytochromes are impaired. 3. At slightly acidic pH, oxygenation of antimycin-supplemented mitochondria causes rapid reduction of cytochrome b566 and small delayed reduction of cytochrome b562. Valinomycin or a pH increase in the medium promote reduction of cytochrome b562 and decrease net reduction of cytochrome b566. 4. Addition of valinomycin to mitochondria and submitochondrial particles in the respiring steady state causes, at pH values around neutrality, preferential oxidation of cytochrome b566 with respect to cytochrome b562. The differential effect of valinomycin on oxidation of cytochromes b566 and b562 is enhanced by substitution of 1H2O of the medium with 2H2O and tends to disappear as the pH of the medium is raised to alkaline values. 5. Nigericin addition in the aerobic steady state causes, both in mitochondria and submitochondrial particles, preferential oxidation of cytochrome b562 with respect to cytochrome b566. This is accompanied by c cytochrome oxidation in mitochondria but c cytochrome reduction in submitochondrial particles. 6. In mitochondria as well as in submitochondrial particles, the aerobic transmembrane potential (delta psi) does not change by raising the pH of the external medium from neutrality to alkalinity. The transmembrane pH gradient (delta pH) on the other hand, decrease slightly. 7. The results presented provide evidence that the delta psi

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.

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

International Nuclear Information System (INIS)

Stoyanova, I.; Rankov, V.; Dimitrov, G.

1978-01-01

The uptake of phosphates by tomato plants, cv.Hebros, was assessed by 32 P 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 N 210 P 210 K 210 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 N 960 P 960 K 720 mineral fertilizer rate was applied. Following prolonged mineral fertilization with growing N rates (from 240 up to 720 kg/ha) at a background of P 720 K 210 , the coefficient of phosphate utilization by tomato plants also diminished from 16.16 to 12.26%. (author)

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

International Nuclear Information System (INIS)

Huertas, M.J.; Saez, L.P.; Roldan, M.D.; Luque-Almagro, V.M.; Martinez-Luque, M.; Blasco, R.; Castillo, F.; Moreno-Vivian, C.; Garcia-Garcia, I.

2010-01-01

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.

Researches on Physico-Chemical and Microbiological Characteristics of Sheep and Cow Milk from Cristian Farm, Romania

Directory of Open Access Journals (Sweden)

Popa Ionuţ Radu

2014-06-01

Full Text Available This study was conducted over a period of three month in the Cristian farm, Sibiu. For the physical, chemical and microbiological analyzes were taken a number of 15 samples per month. From physico-chemical point of view the content evolution of fat, not fat solid substance, density, protein, freezing point, temperature, lactose, conductivity, pH, water addition was followed. Samples were analyzed using the milk analyzer Ekomilk Total of the Research Centre in Biotechnology and Microbiology of the "Lucian Blaga" University. The microbiological contamination of milk was done by determining the total number of bacteria and coliform bacteria. From microbiological point of view it was observed that these conditions are largely met, but a more rigorous control on the cleanliness of utensils and of the staff is required.

Mini-lidar sensor for the remote stand-off sensing of chemical/biological substances and method for sensing same

Science.gov (United States)

Ray, Mark D.; Sedlacek, Arthur J.

2003-08-19

A method and apparatus for remote, stand-off, and high efficiency spectroscopic detection of biological and chemical substances. The apparatus including an optical beam transmitter which transmits a beam having an axis of transmission to a target, the beam comprising at least a laser emission. An optical detector having an optical detection path to the target is provided for gathering optical information. The optical detection path has an axis of optical detection. A beam alignment device fixes the transmitter proximal to the detector and directs the beam to the target along the optical detection path such that the axis of transmission is within the optical detection path. Optical information gathered by the optical detector is analyzed by an analyzer which is operatively connected to the detector.

Negative attributions towards people with substance use disorders in South Africa: Variation across substances and by gender

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Sorsdahl Katherine

2012-08-01

Full Text Available Abstract Background Little research has examined attitudes towards people who use substances in low and middle income countries (LMIC. Therefore, the present study examined the attributions made by the general South African population about people who use substances and whether these attributions differ by the type of substance being used, the gender of the person using the substance, or the characteristics of the person making the attribution. Method A convenience sample of 868 members of the general public was obtained through street-intercept methods. One of 8 vignettes portraying alcohol, cannabis, methamphetamine or heroin, with either a male or female as the protagonist was presented to each respondent. Respondents’ attitudes towards the specific cases were investigated. Results Respondents held equally negative views of the presented substances, with the exception of the cannabis vignette which was considered significantly less “dangerous” than the alcohol vignette. Respondents were more likely to offer “help” to women who use alcohol, but more likely to suggest “coercion into treatment” for men. Individuals who scored higher on the ASSIST were more likely to hold negative attitudes towards substance users and black African respondents were more likely to offer help to individuals who use substances. Conclusion The stigma associated with substance use in South Africa is high and not necessarily dependent on the drug of choice. However, a range of factors, including gender of the substance user, and ethnicity of the rater, may impact on stigma. Interventions designed to strengthen mental health literacy and gender-focused anti-stigma campaigns may have the potential to increase treatment seeking behaviour.

CHEMICAL VAPOUR DEPOSITION FROM A RADIATION-SENSITIVE PRECURSOR

DEFF Research Database (Denmark)

2017-01-01

The present invention relates in one aspect to a method of depositing a thin film on a substrate by chemical vapour deposition (CVD) from a radiation-sensitive precursor substance. The method comprises the steps of: (i) placing the substrate in a reaction chamber of a CVD system; (ii) heating...... heating pulse followed by an idle period; (iii) during at least one of the idle periods, providing a pressure pulse of precursor substance inside the reaction chamber by feeding at least one precursor substance to the reaction chamber so as to establish a reaction partial pressure for thin film deposition...... is formed. According to a further aspect, the invention relates to a chemical vapour deposition (CVD) system for depositing a thin film onto a substrate using precursor substances containing at least one radiation sensitive species....

Field Performance of ISFET based Deep Ocean pH Sensors

Science.gov (United States)

Branham, C. W.; Murphy, D. J.

2017-12-01

Historically, ocean pH time series data was acquired from infrequent shipboard grab samples and measured using labor intensive spectrophotometry methods. However, with the introduction of robust and stable ISFET pH sensors for use in ocean applications a paradigm shift in the methods used to acquire long-term pH time series data has occurred. Sea-Bird Scientific played a critical role in the adoption this new technology by commercializing the SeaFET pH sensor and float pH Sensor developed by the MBARI chemical sensor group. Sea-Bird Scientific continues to advance this technology through a concerted effort to improve pH sensor accuracy and reliability by characterizing their performance in the laboratory and field. This presentation will focus on calibration of the ISFET pH sensor, evaluate its analytical performance, and validate performance using recent field data.

Environmental hazard and risk characterisation of petroleum substances: a guided "walking tour" of petroleum hydrocarbons.

Science.gov (United States)

Bierkens, Johan; Geerts, Lieve

2014-05-01

Petroleum substances are used in large quantities, primarily as fuels. They are complex mixtures whose major constituents are hydrocarbons derived from crude oil by distillation and fractionation. Determining the complete molecular composition of petroleum and its refined products is not feasible with current analytical techniques because of the huge number of molecular components. This complex nature of petroleum products, with their varied number of constituents, all of them exhibiting different fate and effect characteristics, merits a dedicated hazard and risk assessment approach. From a regulatory perspective they pose a great challenge in a number of REACH processes, in particular in the context of dossier and substance evaluation but also for priority setting activities. In order to facilitate the performance of hazard and risk assessment for petroleum substances the European oil company association, CONCAWE, has developed the PETROTOX and PETRORISK spreadsheet models. Since the exact composition of many petroleum products is not known, an underlying assumption of the PETROTOX and PETRORISK tools is that the behaviour and fate of a total petroleum substance can be simulated based on the physical-chemical properties of representative structures mapped to hydrocarbon blocks (HBs) and on the relative share of each HB in the total mass of the product. To assess how differing chemical compositions affect the simulated chemical fate and toxicity of hydrocarbon mixtures, a series of model simulations were run using an artificial petroleum substance, containing 386 (PETROTOX) or 160 (PETRORISK) HBs belonging to different chemical classes and molecular weight ranges, but with equal mass assigned to each of them. To this artificial petroleum substance a guided series of subsequent modifications in mass allocation to a delineated number of HBs belonging to different chemical classes and carbon ranges was performed, in what we perceived as a guided "walking tour

21 CFR 1310.21 - Sale by Federal departments or agencies of chemicals which could be used to manufacture...

Science.gov (United States)

2010-04-01

... chemicals which could be used to manufacture controlled substances. 1310.21 Section 1310.21 Food and Drugs... manufacture controlled substances. (a) A Federal department or agency may not sell from the stocks of the... Administration, could be used in the manufacture of a controlled substance, unless the Administrator certifies in...

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

Science.gov (United States)

Shin, Saemi; Moon, Hyung-Il; Lee, Kwon Seob; Hong, Mun Ki; Byeon, Sang-Hoon

2014-01-01

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. PMID:25419874

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.

Study of lignin standard-substances type biphenyl by {sup 13} C NMR; Estudo de substancias-modelo de lignina do tipo bifenila, por RMN de {sup 13} C

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Marcia Alves; Drumond, Mariza Guimaraes; Veloso, Dorila Pilo [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Quimica

1995-12-31

Lignins structural study by NMR has utilized standard-substances spectral comparative analysis. This work has present relaxation time studies for lignin standard-substance, and {sup 13} C NMR chemical shift values were also shown and compared for several compounds. NMR spectra were commented besides experimental data analysis 2 figs., 4 tabs.

In vitro to in vivo extrapolation of biotransformation rates for assessing bioaccumulation of hydrophobic organic chemicals in mammals.

Science.gov (United States)

Lee, Yung-Shan; Lo, Justin C; Otton, S Victoria; Moore, Margo M; Kennedy, Chris J; Gobas, Frank A P C

2017-07-01

Incorporating biotransformation in bioaccumulation assessments of hydrophobic chemicals in both aquatic and terrestrial organisms in a simple, rapid, and cost-effective manner is urgently needed to improve bioaccumulation assessments of potentially bioaccumulative substances. One approach to estimate whole-animal biotransformation rate constants is to combine in vitro measurements of hepatic biotransformation kinetics with in vitro to in vivo extrapolation (IVIVE) and bioaccumulation modeling. An established IVIVE modeling approach exists for pharmaceuticals (referred to in the present study as IVIVE-Ph) and has recently been adapted for chemical bioaccumulation assessments in fish. The present study proposes and tests an alternative IVIVE-B technique to support bioaccumulation assessment of hydrophobic chemicals with a log octanol-water partition coefficient (K OW ) ≥ 4 in mammals. The IVIVE-B approach requires fewer physiological and physiochemical parameters than the IVIVE-Ph approach and does not involve interconversions between clearance and rate constants in the extrapolation. Using in vitro depletion rates, the results show that the IVIVE-B and IVIVE-Ph models yield similar estimates of rat whole-organism biotransformation rate constants for hypothetical chemicals with log K OW  ≥ 4. The IVIVE-B approach generated in vivo biotransformation rate constants and biomagnification factors (BMFs) for benzo[a]pyrene that are within the range of empirical observations. The proposed IVIVE-B technique may be a useful tool for assessing BMFs of hydrophobic organic chemicals in mammals. Environ Toxicol Chem 2017;36:1934-1946. © 2016 SETAC. © 2016 SETAC.

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

International Nuclear Information System (INIS)

Wong, D.W.; Mishkin, F.; Lee, T.

1978-01-01

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)

REACH: next step to a sound chemicals management.

Science.gov (United States)

Van der Wielen, Arnold

2007-12-01

REACH is the new European Regulation for Registration, Evaluation, Authorisation and Restriction of Chemicals. It entered into force on 1st June 2007 to streamline and improve the former legislative framework on new and on existing chemical substances of the European Union. Companies which manufacture or import more than 1 tonne of a substance per year will be required to register the substance at the new EU Chemicals Agency located in Helsinki. REACH places greater responsibility on industry to manage the risks that chemicals may pose to the health and the environment and to provide safety information that will be passed down the supply chain. In principle, REACH applies to all chemicals as such, as components in preparations and as used in articles. REACH is a radical step forward in the EU chemicals management. The onus will move from the authorities to industry. In addition, REACH will allow the further evaluation of substances where there are grounds for concern, foresees an authorisation system for the use of substances of very high concern and a system of restrictions, where applicable, for substances of concern. The Authorisation system will require companies to switch progressively to safer alternatives where a suitable alternative exists. Current use restrictions will remain under REACH system.

Method of treating the waste liquid of a washing containing a radioactive substance

International Nuclear Information System (INIS)

Sawaguchi, Yusuke; Tsuyuki, Takashi; Kaneko, Masato; Sato, Yasuhiko; Yamaguchi, Takashi.

1975-01-01

Object: To separate waste liquid resulting from washing and which contains a radioactive substance and surface active agent into high purity water and a solid waste substance containing a small quantity of surface active agent. Structure: To waste liquid from a waste liquid tank is added a pH adjusting agent for adjusting the pH to 5.5, and the resultant liquid is sent to an agglomeration reaction tank, in which an inorganic agglomerating agent is added to the waste liquid to cause a major proportion of the radioactive substance and surface active agent to form flocks produced through agglomeration. Then, the waste liquid is sent from the agglomeration reaction tank to a froth separation tank, to which air is supplied through a perforated plate to cause frothing. The over-flowing liquid is de-frothed, and then the insoluble matter is separated as sludge, followed by hydroextraction and drying for solidification. The treated liquid extracted from a froth separation tank is sent to an agglomerating agent recovery tank for separation of the agglomeration agent, and then the residual surface active agent is removed by adsorption in an active carbon adsorption tower, followed by concentration by evaporation in an evaporating can. The concentrated liquid is extracted and then solidified with cement or asphalt. (Kamimura, M.)

A mathematical model of pH, based on the total stoichiometric concentration of acids, bases and ampholytes dissolved in water.

Science.gov (United States)

Mioni, Roberto; Mioni, Giuseppe

2015-10-01

In chemistry and in acid-base physiology, the Henderson-Hasselbalch equation plays a pivotal role in studying the behaviour of the buffer solutions. However, it seems that the general function to calculate the valence of acids, bases and ampholytes, N = f(pH), at any pH, has only been provided by Kildeberg. This equation can be applied to strong acids and bases, pluriprotic weak acids, bases and ampholytes, with an arbitrary number of acid strength constants, pKA, including water. By differentiating this function with respect to pH, we obtain the general equation for the buffer value. In addition, by integrating the titration curve, TA, proposed by Kildeberg, and calculating its Legendre transform, we obtain the Gibbs free energy of pH (or pOH)-dependent titratable acid. Starting from the law of electroneutrality and applying suitable simplifications, it is possible to calculate the pH of the buffer solutions by numerical methods, available in software packages such as Excel. The concept of buffer capacity has also been clarified by Urbansky, but, at variance with our approach, not in an organic manner. In fact, for each set of monobasic, dibasic, tribasic acids, etc., various equations are presented which independently fit each individual acid-base category. Consequently, with the increase in acid groups (pKA), the equations become more and more difficult, both in practice and in theory. Some examples are proposed to highlight the boundary that exists between acid-base physiology and the thermodynamic concepts of energy, chemical potential, amount of substance and acid resistance.

Developing human health exposure scenarios for petroleum substances under REACH

Energy Technology Data Exchange (ETDEWEB)

Carter, M.; De Wilde, P.; Maksimainen, K.; Margary, A.; Money, C.; Pizzella, G.; Svanehav, T.; Tsang, W.; Urbanus, J.; Rohde, A.

2012-12-15

This report describes the approaches that were adopted by CONCAWE to prepare the human exposure estimates in the chemical safety assessments of the REACH registration dossiers for petroleum substances based on all applicable regulatory guidance. Separate exposure estimates were developed for workers and for consumers and included inhalation and dermal routes. The complex nature of petroleum substances required various scientifically justified refinements of the regulatory guidance.

An ultrasensitive method of real time pH monitoring with complementary metal oxide semiconductor image sensor.

Science.gov (United States)

Devadhasan, Jasmine Pramila; Kim, Sanghyo

2015-02-09

CMOS sensors are becoming a powerful tool in the biological and chemical field. In this work, we introduce a new approach on quantifying various pH solutions with a CMOS image sensor. The CMOS image sensor based pH measurement produces high-accuracy analysis, making it a truly portable and user friendly system. pH indicator blended hydrogel matrix was fabricated as a thin film to the accurate color development. A distinct color change of red, green and blue (RGB) develops in the hydrogel film by applying various pH solutions (pH 1-14). The semi-quantitative pH evolution was acquired by visual read out. Further, CMOS image sensor absorbs the RGB color intensity of the film and hue value converted into digital numbers with the aid of an analog-to-digital converter (ADC) to determine the pH ranges of solutions. Chromaticity diagram and Euclidean distance represent the RGB color space and differentiation of pH ranges, respectively. This technique is applicable to sense the various toxic chemicals and chemical vapors by situ sensing. Ultimately, the entire approach can be integrated into smartphone and operable with the user friendly manner. Copyright © 2014 Elsevier B.V. All rights reserved.

The preservation of substance P by lysergic acid diethylamide.

Science.gov (United States)

KRIVOY, W A

1957-09-01

Lysergic acid diethylamide (LSD) potentiated the response of guinea-pig ileum to substance P but not to histamine. It also inhibited the disappearance of substance P when incubated with guinea-pig brain extract but not when incubated with chymotrypsin. Eserine, morphine, mescaline, chlorpromazine, ergometrine, strychnine and 2 bromo-LSD did not have this effect. Oxytocin was not destroyed by brain extract. The inhibition of the destruction of substance P by LSD could be antagonized by 2 bromo-LSD. This effect of LSD may have some relation to its pharmacological actions.

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

International Nuclear Information System (INIS)

Winkler, P.; Pahl, S.

1993-10-01

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 [de

Evaluation of Amazon fruits: chemical and nutritional studies on Borojoa sorbilis.

Science.gov (United States)

Rabelo Rodrigues, Francimilton; de Souza Ramos, Aline; Fernandes Amaral, Ana Claudia; Pinto Ferreira, José Luiz; da Silva Carneiro, Carla; Rocha de Andrade Silva, Jefferson

2018-01-31

Borojoa sorbilis (Ducke) is an Amazonian species with edible fruits that are widely consumed by the local population, but little studied and not yet economically explored. Thus the aim of this study was to describe the chemical composition, volatile compounds, nutritional aspects and antioxidant activity of the fruit pulp and peel of B. sorbilis. Headspace solid-phase microextraction, using polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber, resulted in the identification of 59 substances in the pulp and peel of B. sorbilis fruits after analysis of the chromatograms obtained by gas chromatography-mass spectrometry using polar and nonpolar columns. Esters were the most abundant. Moisture, lipids, protein, dietary fiber, ash, carbohydrate, total energy value, titratable acid, soluble solids and pH were measured. Protein amount, fat content and antioxidant activity were low in both pulp and peel. Carbohydrate content was 179.2 and 134.9 g kg -1 in pulp and peel, respectively. This is the first report on the chemical characteristics, flavor and nutritional aspects of B. sorbilis fruit, which is essential to its economic exploitation. The high energy value associated with the carbohydrate content, plus the low fat content, contribute to a possible use of B. sorbilis fruits as a food supplement. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

METHOD FOR THE ESTIMATION OF SOIL VULNERABILITY AT THE CHEMICAL AGENTS IMPACT

Directory of Open Access Journals (Sweden)

Radu Lacatusu

2006-10-01

Full Text Available The negative effect induced to the soil by any impact, commonly chemical impact, defining the soil vulnerability to this impulse. To put in equation this soil characteristic, were chosen these physical and chemical indicators which determining the phenomenon intensity and its evolution direction, as: texture, pH (soil reaction, organic matter content, carbonates content and ion exchange capacity. Each of these indicators was divided into five classes, depending on the content in elements and/or chemical substances that defining any indicator, the specific indicator size, and on the direction and intensity of process generated by impact. Every of these five classes have been got marks from one to five according to soil capacity to putting up resistance to modification induced by impact. One mark reflecting the lowest impact resistance and five mark the highest ones. By summing of characteristic marks for each class resulted a scale from 5 to 25. According to this scale we could have very high soil vulnerability with only 5 points, and an invulnerable soil with 25 points. Analytical data of all these five physics and chemical indicators, determined for a specific territory, could be framing in vulnerability scale according to the presented methodology. This methodology permit to realize maps of the specific territories for soils vulnerability to impact of any nature chemical agents.

Preparation of acridine orange-doped silica nanoparticles for pH measurement

International Nuclear Information System (INIS)

Liu, Jinshui; Zang, Lingjie; Wang, Yiru; Liu, Guoning

2014-01-01

Acridine orange was first encapsulated into silica shell via a facile reverse microemusion method to built core–shell fluorescent nanoparticles. The nanoparticles are all in spherical shape and have a narrow size distribution, and its application as a optical pH sensor has been demonstrated. This novel sensor is based on the pH-dependent fluorescence intensities of acridine orange in different pH value. The fluorescence intensity of acridine orange-doped silica nanoparticles was decreased by increasing pH value. Under optimum conditions, the changes of fluorescence intensity were proportional to the pH value in the range of 8.00–10.90. In addition, the sensor can be easily separated by centrifugation and adds no pollution to the environment compared to the free dyes. Furthermore, the effects of ionic strength and co-existing substances were proved to have little influence on the determination of pH. The sensor has been successfully applied to determine the pH of two artificial samples. Hence, the core–shell fluorescent nanoparticles show potential for practical application. -- Highlights: • Acridine orange was encapsulated into silica shell via a facile reverse microemusion method to built core–shell fluorescent nanoparticles. • The fluorescence intensity of acridine orange-doped silica nanoparticles was decreased by increasing pH value. • Its can be used as an optical pH sensor. • The sensor can be easily separated by centrifugation and adds no pollution to the environment compared to the free dyes. • The sensor has been successfully applied to determine the pH of artificial samples

Ocean acidification affects marine chemical communication by changing structure and function of peptide signalling molecules.

Science.gov (United States)

Roggatz, Christina C; Lorch, Mark; Hardege, Jörg D; Benoit, David M

2016-12-01

Ocean acidification is a global challenge that faces marine organisms in the near future with a predicted rapid drop in pH of up to 0.4 units by the end of this century. Effects of the change in ocean carbon chemistry and pH on the development, growth and fitness of marine animals are well documented. Recent evidence also suggests that a range of chemically mediated behaviours and interactions in marine fish and invertebrates will be affected. Marine animals use chemical cues, for example, to detect predators, for settlement, homing and reproduction. But, while effects of high CO 2 conditions on these behaviours are described across many species, little is known about the underlying mechanisms, particularly in invertebrates. Here, we investigate the direct influence of future oceanic pH conditions on the structure and function of three peptide signalling molecules with an interdisciplinary combination of methods. NMR spectroscopy and quantum chemical calculations were used to assess the direct molecular influence of pH on the peptide cues, and we tested the functionality of the cues in different pH conditions using behavioural bioassays with shore crabs (Carcinus maenas) as a model system. We found that peptide signalling cues are susceptible to protonation in future pH conditions, which will alter their overall charge. We also show that structure and electrostatic properties important for receptor binding differ significantly between the peptide forms present today and the protonated signalling peptides likely to be dominating in future oceans. The bioassays suggest an impaired functionality of the signalling peptides at low pH. Physiological changes due to high CO 2 conditions were found to play a less significant role in influencing the investigated behaviour. From our results, we conclude that the change of charge, structure and consequently function of signalling molecules presents one possible mechanism to explain altered behaviour under future oceanic pH

Characterization of an organ-specific differentiator substance in the planarian Dugesia etrusca

Energy Technology Data Exchange (ETDEWEB)

Steele, V.E.; Lange, C.S.

1977-01-01

A substance which inhibits brain formation in decapitated regenerating planarians (Dugesia etrusca) was characterized and partially purified. The substance's inhibitory activity was followed during each purification procedure by adding freshly decapitated animals of a standard size to each fraction, and later measuring the resultant regenerated brain volume. The inhibitory activity remained in the supernatant after a 10000 g centrifugation of a cell-free homogenate. Most of the activity sedimented when the 10000 g supernatant was centrifuged at 32000 g. The degree of inhibitory activity increased with increased numbers of animals in the initial homogenate. The substance has an apparent molecular weight between 2 x 10/sup 5/ and 4 x 10/sup 5/ daltons. Digestion by pronase destroyed the activity, but treatment with RNase, DNase I, or lipase had no significant effect. The inhibiting substance has an isoelectric point (pI) of between 4.75 and 5.38 and migrates to the anode when electrophorezed in pH 6.8 buffer.

Synthesis of Nickel and Nickel Hydroxide Nanopowders by Simplified Chemical Reduction

Directory of Open Access Journals (Sweden)

Jeerapan Tientong

2014-01-01

Full Text Available Nickel nanopowders were synthesized by a chemical reduction of nickel ions with hydrazine hydrate at pH ~12.5. Sonication of the solutions created a temperature of 54–65°C to activate the reduction reaction of nickel nanoparticles. The solution pH affected the composition of the resulting nanoparticles. Nickel hydroxide nanoparticles were formed from an alkaline solution (pH~10 of nickel-hydrazine complexed by dropwise titration. X-ray diffraction of the powder and the analysis of the resulting Williamson-Hall plots revealed that the particle size of the powders ranged from 12 to 14 nm. Addition of polyvinylpyrrolidone into the synthesis decreased the nickel nanoparticle size to approximately 7 nm. Dynamic light scattering and scanning electron microscopy confirmed that the particles were in the nanometer range. The structure of the synthesized nickel and nickel hydroxide nanoparticles was identified by X-ray diffraction and Fourier transform infrared spectroscopy.

Engineering a pH responsive pore forming protein.

Science.gov (United States)

Kisovec, Matic; Rezelj, Saša; Knap, Primož; Cajnko, Miša Mojca; Caserman, Simon; Flašker, Ajda; Žnidaršič, Nada; Repič, Matej; Mavri, Janez; Ruan, Yi; Scheuring, Simon; Podobnik, Marjetka; Anderluh, Gregor

2017-02-08

Listeriolysin O (LLO) is a cytolysin capable of forming pores in cholesterol-rich lipid membranes of host cells. It is conveniently suited for engineering a pH-governed responsiveness, due to a pH sensor identified in its structure that was shown before to affect its stability. Here we introduced a new level of control of its hemolytic activity by making a variant with hemolytic activity that was pH-dependent. Based on detailed structural analysis coupled with molecular dynamics and mutational analysis, we found that the bulky side chain of Tyr406 allosterically affects the pH sensor. Molecular dynamics simulation further suggested which other amino acid residues may also allosterically influence the pH-sensor. LLO was engineered to the point where it can, in a pH-regulated manner, perforate artificial and cellular membranes. The single mutant Tyr406Ala bound to membranes and oligomerized similarly to the wild-type LLO, however, the final membrane insertion step was pH-affected by the introduced mutation. We show that the mutant toxin can be activated at the surface of artificial membranes or living cells by a single wash with slightly acidic pH buffer. Y406A mutant has a high potential in development of novel nanobiotechnological applications such as controlled release of substances or as a sensor of environmental pH.

Engineering a pH responsive pore forming protein

Science.gov (United States)

Kisovec, Matic; Rezelj, Saša; Knap, Primož; Cajnko, Miša Mojca; Caserman, Simon; Flašker, Ajda; Žnidaršič, Nada; Repič, Matej; Mavri, Janez; Ruan, Yi; Scheuring, Simon; Podobnik, Marjetka; Anderluh, Gregor

2017-02-01

Listeriolysin O (LLO) is a cytolysin capable of forming pores in cholesterol-rich lipid membranes of host cells. It is conveniently suited for engineering a pH-governed responsiveness, due to a pH sensor identified in its structure that was shown before to affect its stability. Here we introduced a new level of control of its hemolytic activity by making a variant with hemolytic activity that was pH-dependent. Based on detailed structural analysis coupled with molecular dynamics and mutational analysis, we found that the bulky side chain of Tyr406 allosterically affects the pH sensor. Molecular dynamics simulation further suggested which other amino acid residues may also allosterically influence the pH-sensor. LLO was engineered to the point where it can, in a pH-regulated manner, perforate artificial and cellular membranes. The single mutant Tyr406Ala bound to membranes and oligomerized similarly to the wild-type LLO, however, the final membrane insertion step was pH-affected by the introduced mutation. We show that the mutant toxin can be activated at the surface of artificial membranes or living cells by a single wash with slightly acidic pH buffer. Y406A mutant has a high potential in development of novel nanobiotechnological applications such as controlled release of substances or as a sensor of environmental pH.

Radiotracer study of sorption of europium on Gorleben sand from aqueous solutions containing humic substances

International Nuclear Information System (INIS)

Benes, P.; Stamberg, K.; Siroky, L.; Mizera, J.

2002-01-01

The sorption of trace europium, as a trivalent actinide homologue, was studied in the system Gorleben sand - aqueous solution with the aim to elucidate its mechanism. Radiotracer method ( 152/154 Eu) and batch experiments were used. Simultaneously, the distribution of humic substances present in, or added to the system was measured. The evaluation of the sorption was complicated by the adsorption of Eu on the walls of polyethylene vials used for the experiments, which was rather high and had to be taken into consideration. It has been found that Eu sorption on Gorleben sand increases from pH 2 to pH 5-7 and then it decreases. The decrease is due to the complexation of Eu with humic substances leached from Gorleben sand at pH>7. The position of the sorption maximum depends on the composition of the solution and on the liquid-to-solid ratio. It is shifted to lower pH values in the presence of added humic acid (HA), which enhances Eu sorption at low PH values and suppresses it at pH values higher than 5. The regions of the enhancing/suppressing effects coincidence with the high/low adsorption of HA on Gorleben sand, respectively. The increasing ionic strength (from 0.01 to 0.1) and europium concentration (3.4 x 10 -8 to 9.3 x 10 -7 mol/l) suppress the relative sorption (expressed in %) at low pH values and enhance it at pH>6-8. Addition of carbonates (5 x 10 -3 mol/l) supports Eu sorption at pH>7.5 so that no decrease with pH is observed till pH 9. Alkaline leaching of the sand significantly changes most of the effects found. These results were qualitatively interpreted and conclusions were drawn on the mechanism of the sorption. (author)

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.

Metal homeostasis in Hypogymnia physodes is controlled by lichen substances.

Science.gov (United States)

Hauck, Markus

2008-05-01

The hypothesis was tested that the lichen substances produced by the epiphytic lichen Hypogymnia physodes control the intracellular uptake of divalent transition metals. Incubating lichen thalli with and without their natural content of lichen substances with metal solutions showed that the lichen substances of H. physodes selectively inhibit the uptake of Cu(2+) and Mn(2+), but not of Fe(2+) and Zn(2+). Such behavior is ecologically beneficial, as ambient concentrations of Cu(2+) and Mn(2+) in precipitation and bark are known to limit the abundance of H. physodes, whereas limiting effects of Fe(2+) or Zn(2+) have never been found. This suggests that increasing the Cu(2+) and Mn(2+) tolerance stimulated the evolution of lichen substances in H. physodes. The depsidone physodalic acid is apparently most effective at reducing Cu(2+) and Mn(2+) uptake among the seven lichen substances produced by H. physodes. Probably lichen substances play a general role in the metal homeostasis of lichens.

Assessing the effects of seawater temperature and pH on the bioaccumulation of emerging chemical contaminants in marine bivalves

DEFF Research Database (Denmark)

Maulvault, Ana Luísa; Camacho, Carolina; Barbosa, Vera

2017-01-01

Emerging chemical contaminants [e.g. toxic metals speciation, flame retardants (FRs) and perfluorinated compounds (PFCs), among others], that have not been historically recognized as pollutants nor their toxicological hazards, are increasingly more present in the marine environment. Furthermore......, the effects of environmental conditions (e.g. temperature and pH) on bioaccumulation and elimination mechanisms of these emerging contaminants in marine biota have been poorly studied until now. In this context, the aim of this study was to assess, for the first time, the effect of warmer seawater...... and Ruditapes philippinarum). Overall, results showed that warming alone or combined with acidification promoted the bioaccumulation of some compounds (i.e. dechloranes 602, 604, TBBPA), but also facilitated the elimination of others (i.e. iAs, TBBPA). Similarly, lower pH also resulted in higher levels...

Production of an antimicrobial substance against Cryptococcus neoformans by Paenibacillus brasilensis Sa3 isolated from the rhizosphere of Kalanchoe brasiliensis.

Science.gov (United States)

Fortes, Tiago Oliveira; Alviano, Daniela Sales; Tupinambá, Gleiser; Padrón, Thaís Souto; Antoniolli, Angelo Roberto; Alviano, Celuta Sales; Seldin, Lucy

2008-01-01

An antifungal substance produced by Paenibacillus brasilensis strain Sa3 was preliminary characterized and showed to be stable after treatment with different enzymes and organic solvents and at a wide range of pH, and presented a molecular weight between 3 and 10 kDa. In vitro antagonism of this strain towards Cryptococcus neoformans was investigated by optical and electronic microscopic analyses and a fungicidal effect on C. neoformans was observed. Ultrastructural analysis showed intense changes on the fungus when it was paired cultured with strain Sa3, mainly the detachment of the capsule from the cell wall and the presence of altered organelles in the cytoplasm. This novel antifungal substance produced by P. brasilensis Sa3 may represent a new insight in antifungal therapy mainly against emergent fungi. Also, prospective studies on rhizobacteria of plants as Kalanchoe brasiliensis may offer a potential source for the discovery of bioactive compounds with medical value.

Effects of pH and Cation Composition on Sorption of Per- and Polyfluoroalkyl Substances (PFASs) to Soil Particles

OpenAIRE

Ullberg, Malin

2015-01-01

Per- and polyfluoroalkyl substances (PFASs) have drawn great attention recently, due to their environmental persistence, potential toxicity and global distribution. PFAS is a large family of substances, characterized by a perflourinated carbon chain and a functional group. All PFASs are synthetic and have been widely used since the 1950s due to their unique properties of being both hydrophobic and oleophobic, making them useful for many industries. To be able to predict the fate of PFASs in t...

Journal of NIRE, Vol. 5, No. 1, January 1996. Special issue: Behavior in the environment and countermeasure technology of hazardous chemicals

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-01-01

Contents: Technique for Management of Hazardous Chemical Substances --Risk Assessment; Behaviors of Chemicals in the Aquatic Environment; Numerical Model of Chemical Fate in an Environment; Source Characterization and Chemical Processes of Volatile Organic Compounds in the Atmosphere; Development of Sensor for Hazardous Substances; Removal of Chemical Substances from the Atmosphere by Photocatalysis; Microbial Degradation of Organic Xenobiotics in Environment.

Zinc(II Adsorption by Low-Carbon Shungite: The Effect of pH

Directory of Open Access Journals (Sweden)

Axel R. Fischer

2018-04-01

Full Text Available Shungite is a carbonaceous rock which is abundant in Karelia (Russian Federation. Large deposits of shungite with low levels of carbon (approx. 10% C are also found in Kazakhstan, where it is mined under the trade name Taurit (Koksu Mining Company. Although Taurit has been reported to be used as an adsorbent for hazardous compounds in water treatment, there is very little precise data about its adsorption capacity or the compounds adsorbed. In this study, the ability of Taurit to adsorb Zn(II was investigated and Freundlich isotherms were determined for both distilled water and tap water. Taurit was found to have a high buffer capacity leading to pH values > 7.0 in aqueous solution. Because dissolved zinc precipitates as Zn(OH2 under alkaline conditions, the pH must be carefully controlled and kept ≤7.0. Despite the small inner surface area (BET of Taurit (13.4 m2 g−1, Freundlich coefficients for distilled water (Kf = 2.4, n = 4.0 and tap water (Kf = 1.5, n = 2.5 were similar to other adsorbents. Our results indicate that Taurit could provide a cheap alternative to activated carbon since both substances have a similar adsorption capacity (at least for Zn(II.

Metal homeostasis in Hypogymnia physodes is controlled by lichen substances

International Nuclear Information System (INIS)

Hauck, Markus

2008-01-01

The hypothesis was tested that the lichen substances produced by the epiphytic lichen Hypogymnia physodes control the intracellular uptake of divalent transition metals. Incubating lichen thalli with and without their natural content of lichen substances with metal solutions showed that the lichen substances of H. physodes selectively inhibit the uptake of Cu 2+ and Mn 2+ , but not of Fe 2+ and Zn 2+ . Such behavior is ecologically beneficial, as ambient concentrations of Cu 2+ and Mn 2+ in precipitation and bark are known to limit the abundance of H. physodes, whereas limiting effects of Fe 2+ or Zn 2+ have never been found. This suggests that increasing the Cu 2+ and Mn 2+ tolerance stimulated the evolution of lichen substances in H. physodes. The depsidone physodalic acid is apparently most effective at reducing Cu 2+ and Mn 2+ uptake among the seven lichen substances produced by H. physodes. Probably lichen substances play a general role in the metal homeostasis of lichens. - Lichen substances in Hypogymnia physodes specifically reduce the uptake of Cu 2+ and Mn 2+ , but not Fe 2+ or Zn 2+

Chemical alteration of cement hydrates by dissolution

International Nuclear Information System (INIS)

Sugiyama, Daisuke; Fujita, Tomonari; Nakanishi, Kiyoshi

2000-01-01

Cementitious material is a potential waste packaging and backfilling material for the radioactive waste disposal, and is expected to provide both physical and chemical containment. In particular, the sorption of radionuclides onto cementitious material and the ability to provide a high pH condition are very important parameters when considering the release of radionuclides from radioactive wastes. For the long term, in the geological disposal environment, cement hydrates will be altered by, for example, dissolution, chemical reaction with ions in the groundwater, and hydrothermal reaction. Once the composition or crystallinity of the constituent minerals of a cement hydrate is changed by these processes, the pH of the repository buffered by cementitious material and its sorption ability might be affected. However, the mechanism of cement alteration is not yet fully understood. In this study, leaching experiments of some candidate cements for radioactive waste disposal were carried out. Hydrated Ordinary Portland Cement (OPC), Blast Furnace Slag blended cement (OPC/BFS) and Highly containing Flyash and Silicafume Cement (HFSC) samples were contacted with distilled water at liquid:solid ratios of 10:1, 100:1 and 1000:1 at room temperature for 200 days. In the case of OPC, Ca(OH) 2 dissolved at high liquid:solid ratios. The specific surface area of all cement samples increased by leaching process. This might be caused by further hydration and change of composition of constituent minerals. A model is presented which predicts the leaching of cement hydrates and the mineral composition in the hydrated cement solid phase, including the incongruent dissolution of CSH gel phases and congruent dissolution of Ca(OH) 2 , Ettringite and Hydrotalcite. Experimental results of dissolution of Ca-O-H and Ca-Si-O-H phases were well predicted by this model. (author)

[Simultaneous determination of four common nonprotein nitrogen substances in urine by high performance liquid chromatography].

Science.gov (United States)

Ma, Yuhua; Huang, Dongqun; Zhang, Rui; Xu, Shiru; Feng, Shun

2013-11-01

A high performance liquid chromatographic (HPLC) method was proposed to simultaneously determine four common nonprotein nitrogen substances, including creatine (Cr), creatinine (Cn), uric acid (Ua) and pseudouridine (Pu) in urine. After proteins being removed by acetone precipitation method, freeze drying and redissolving, the urine samples were analyzed by HPLC. Chromatographic separation was performed on a Waters RP18 Column (150 mm x 4.60 mm, 3.5 microm) in gradient elution mode using 10.0 mmol/L KH2PO4 solution (pH 4.78) and acetonitrile as mobile phases at a flow rate of 0.8 mL/min. The samples were detected at 220 nm. Rapid separation was achieved within 7 min. Under the optimized conditions, good linearities of four common nonprotein nitrogen substances were obtained in the range of 0.1-250 mg/L. The detection limits were 9.31 (Cr), 26.19 (Cn), 4.70 (Ua), an 6.30 (Pu) microg/L and the recoveries were in the range of 81%-111% with the relative standar deviations of 0.23%-2.78% (n = 3). The results demonstrate that this method is simple, rapid and accurate with good reproducibility, and can provide early diagnosis and preliminary judgment for type 2 diabetes mellitus (T2DM) patients with renal damage.

[Simultaneous separation and detection of principal component isomer and related substances of raw material drug of ammonium glycyrrhizinate by RP-HPLC and structure confirmation].

Science.gov (United States)

Zhao, Yan-Yan; Liu, Li-Yan; Han, Yuan-Yuan; Li, Yue-Qiu; Wang, Yan; Shi, Min-Jian

2013-08-01

A simple, fast and sensitive analytical method for the simultaneous separation and detection of 18alpha-glycyrrhizinic acid, 18beta-glycyrrhizinic acid, related substance A and related substance B by RP-HPLC and drug quality standard was established. The structures of principal component isomer and related substances of raw material drug of ammonium glycyrrhizinate have been confirmed. Reference European Pharmacopoeia EP7.0 version, British Pharmacopoeia 2012 version, National Drug Standards of China (WS 1-XG-2002), domestic and international interrelated literature were referred to select the composition of mobile phase. The experimental parameters including salt concentration, pH, addition quantities of organic solvent, column temperature and flow rate were optimized. Finally, the assay was conducted on a Durashell-C18 column (250 mm x 4.6 mm, 5 microm) with 0.01 mol x mL(-1) ammonium perchlorate (add ammonia to adjust the pH value to 8.2) -methanol (48 : 52) as mobile phase at the flow rate of 0.8 mL x min(-1), and the detection wavelength was set at 254 nm. The column temperature was 50 degrees C and the injection volume was 10 microL. The MS, NMR, UV and RP-HPLC were used to confirm the structures of principal component isomer and related substances of raw material drug of ammonium glycyrrhizinate. Under the optimized separation conditions, the calibration curves of 18 alpha-glycyrrhizinic acid, 18beta-glycyrrhizinic acid, related substance A and related substance B showed good linearity within the concentration of 0.50-100 microg x mL(-1) (r = 0.999 9). The detection limits for 18alpha-glycyrrhizinic acid, 18beta-glycyrrhizinic acid, related substance A and related substance B were 0.15, 0.10, 0.10, 0.15 microg x mL(-1) respectively. The method is sensitive, reproducible and the results are accurate and reliable. It can be used for chiral resolution of 18alpha-glycyrrhizinic acid, 18Pbeta-glycyrrhizinic acid, and detection content of principal component and

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.

Synthesis of Nickel and Nickel Hydroxide Nano powders by Simplified Chemical Reduction

International Nuclear Information System (INIS)

Tientong, J.; Garcia, S.; Thurber, C.R.; Golden, T.D.

2014-01-01

Nickel nano powders were synthesized by a chemical reduction of nickel ions with hydrazine hydrate at ph ∼ 12.5. Sonication of the solutions created a temperature of 54-65 °C to activate the reduction reaction of nickel nanoparticles. The solution ph affected the composition of the resulting nanoparticles. Nickel hydroxide nanoparticles were formed from an alkaline solution (ph ∼10) of nickel-hydrazine complexed by dropwise titration. X-ray diffraction of the powder and the analysis of the resulting Williamson-Hall plots revealed that the particle size of the powders ranged from 12 to 14 nm. Addition of polyvinylpyrrolidone into the synthesis decreased the nickel nanoparticle size to approximately 7 nm. Dynamic light scattering and scanning electron microscopy confirmed that the particles were in the nanometer range. The structure of the synthesized nickel and nickel hydroxide nanoparticles was identified by X-ray diffraction and Fourier transform infrared spectroscopy.

Hypothesis for prediction of environmental stability of chemicals by mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Tremolada, P; Di Guardo, A; Calamari, D; Davoli, E; Fanelli, R [Milan Univ. (Italy). Ist. di Entomologia Agraria Istituto di Ricerche Farmacologiche Mario Negri, Milan (Italy)

1992-01-01

The environmental persistence of organic chemicals is generally very hard to predict. In this work, the hypothesis of the use of fragmentation data in Mass Spectrometry (MS) as a possible 'stability index' of the molecules is presented. Since the fragmentation is determined by the thermodynamic properties of the molecules, it is possible to deduct information about the 'intrinsic stability' of a chemical. Such information can be used and correlated to predict the environmental degradability of a substance, especially referring to abiotic degradation. To study this relation, three different methods of measuring the fragmentation patterns are compared. All the methods show similar behaviour and one of them, in particular, shows a very good qualitative correlation between fragmentation data and persistence values found in literature. A possible 'stability index' for the quantitative prediction of the environmental degradation of a chemical is discussed.

Ultrafine fibers of zein and anthocyanins as natural pH indicator.

Science.gov (United States)

Prietto, Luciana; Pinto, Vania Zanella; El Halal, Shanise Lisie Mello; de Morais, Michele Greque; Costa, Jorge Alberto Vieira; Lim, Loong-Tak; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

2018-05-01

pH-sensitive indicator membranes, which are useful for pharmaceutical, food, and packaging applications, can be formed by encapsulating halochromic compounds within various solid supports. Accordingly, electrospinning is a versatile technique for the development of these indicators, by entrapping pH dyes within ultrafine polymer fibers. The ultrafine zein fibers, containing 5% (w/v) anthocyanins, had an average diameter of 510 nm. The pH-sensitive membrane exhibited color changes from pink to green when exposed to acidic and alkaline buffers, respectively. The contact angle was negligible after 10 and 2 s for neat and 5% anthocyanin-loaded zein membranes, respectively. The pH membranes exhibited color changes in a board pH range, which can potentially be used in various active packaging applications. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Chemical and structural characterization of soil humic substances under agroforestry and conventional systems

Directory of Open Access Journals (Sweden)

Gislane M. de Moraes

2011-10-01

Full Text Available Studies have proven that the agroforestry systems in the semi-arid region of the State of Ceará, Brazil, induce an increase in soil organic C levels. Notwithstanding, there is no information if this increase also results in qualitative changes in different pools of soil organic matter. The objective of this study was to verify the possible chemical and structural alterations in fulvic and humic acids of a Luvisol in areas adopting agroforestry, traditional intensive cultivation and native forest in a long-term experiment conducted in the semi-arid region of Ceará State, Brazil. The study was conducted in an experimental area of the National Goat Research Center (Embrapa in Sobral, CE. The following treatments were evaluated: agrosilvopasture (AGP, silvopasture (SILV, intensive cultivation under fallow (ICF, and areas with native forest (NF. Soil fulvic and humic acids fractions were extracted from the 0-6 and 6-12 cm layers and characterized by elemental composition, thermogravimetry and infrared spectroscopy analyses. The elemental composition analysis of humic acids confirmed the data found for fulvic acids, showing reduction in the C, H and N levels, followed by an increase in O contents in the AGP and ICF treatments over SILV and NF. In all treatments, except to SILV in the 0-6 cm layer, the percentage of mass loss was highest (300-600 °C for humic acids in the thermally most stable region. Despite the similarity between infrared spectra, soil fulvic acids in the SILV treatment extracted from 6-12 cm depth decrease the absorption bands at 1708 and 1408 cm-1 followed by an increase in the absorption band at 1608 cm-1 attributed to aromatic C=C groups. This behavior suggests an increase in the aromatic character of the structure. The AGP and ICF treatments, which increase the soil tilling, favored the maintenance of humic substances with a more aromatic character in the soil than SILV and NF. The less aromatic humic substances in the SILV

Monitoring of internal pH gradients within multi-layer tablets by optical methods and EPR imaging.

Science.gov (United States)

Eisenächer, Friederike; Schädlich, Andreas; Mäder, Karsten

2011-09-30

The high variability of gastrointestinal pH is a general challenge regarding constant release from oral drug delivery systems, especially for ionisable drugs. These drugs often show a pH-dependent solubility and therewith associated intra- and inter-individual variability of emerging drug plasma levels. Several strategies have been investigated with the intention to influence the microenvironmental pH (pH(M)) within solid formulations and therefore achieve pH-independent release profiles. Because of the heterogeneity of solid systems, a precise prediction of the occurring pH(M) is rather difficult. It is therefore important to monitor the pH(M) within the formulations to achieve requested release as well as to minimise pH-dependent degradation processes of the active compound. The purpose of the current study was the analysis of pH(M) gradients within 2- and 3-layer tablets during hydration using 3 different techniques for comparison intensions, in particular a pH indicator dye, fluorescence imaging and EPR imaging. The influence of the presence or absence of pH modifying substances and of an additional lipophilic inter layer on the pH(M) was investigated as well as the variation of matrix forming excipient and buffer pH. The influence of the pH(M) on drug release was analysed as well. In addition, benchtop MRI was accomplished to gain a deeper insight on the hydration and erosion behaviour of 2- and 3-layer tablets. Copyright © 2010 Elsevier B.V. All rights reserved.

Chemical warfare in freshwater. Allelpathic effects of macrophytes on phytoplankton

NARCIS (Netherlands)

Mulderij, G.

2006-01-01

Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field

Chemical warfare in freshwater, allelopathic effects of macrophytes on phytoplankton

NARCIS (Netherlands)

Mulderij, G.

2006-01-01

Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field

Colour quantitation for chemical spot tests for a controlled substances presumptive test database.

Science.gov (United States)

Elkins, Kelly M; Weghorst, Alex C; Quinn, Alicia A; Acharya, Subrata

2017-02-01

Crime scene investigators (CSIs) often encounter unknown powders, capsules, tablets, and liquids at crime scenes, many of which are controlled substances. Because most drugs are white powders, however, visual determination of the chemical identity is difficult. Colourimetric tests are a well-established method of presumptive drug identification. Positive tests are often reported differently, however, because two analysts may perceive colour or record colourimetric results in different ways. In addition to perceiving colour differently, it is very common for there to be poor visibility conditions (e.g. rain, darkness) while performing these tests, further obscuring the results. In order to address these concerns and to create uniformity in the reporting of on-site colourimetric test results, this study has evaluated two of the state-of-the-art apps (ColorAssist® and Colorimeter®) for reporting the colour test results quantitatively in red-green-blue (RGB) format. The compiled library database of presumptive test results contains over 3300 data points including over 800 unique drug/test combinations. Variations observed between test replicates, from performing a test on different days, recording with a different device type (e.g. iPod Touch, iPhone models 4, 5c, 5s, or 6), and using different quantities of drug are discussed. Overall, the least variation in Euclidian norm was observed using ColorAssist® with the camera light (25.1±22.1) while the variation between replicates and data recorded using different devices was similar. The resulting library is uploaded to a smartphone application aimed to aid in identifying and interpreting suspected controlled substance evidence. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Geochemical behaviour of palladium in soils and Pd/PdO model substances in the presence of the organic complexing agents L-methionine and citric acid.

Science.gov (United States)

Zereini, Fathi; Wiseman, Clare L S; Vang, My; Albers, Peter; Schneider, Wolfgang; Schindl, Roland; Leopold, Kerstin

2016-01-01

Risk assessments of platinum group metal (PGE) emissions, notably those of platinum (Pt), palladium (Pd) and rhodium (Rh), have been mostly based on data regarding the metallic forms used in vehicular exhaust converters, known to be virtually biologically inert and immobile. To adequately assess the potential impacts of PGE, however, data on the chemical behaviour of these metals under ambient conditions post-emission is needed. Complexing agents with a high affinity for metals in the environment are hypothesized to contribute to an increased bioaccessibility of PGE. The purpose of this study is to examine the modulating effects of the organic complexing agents, L-methionine and citric acid, on the geochemical behavior of Pd in soils and model substances (Pd black and PdO). Batch experimental tests were conducted with soils and model substances to examine the impacts of the concentration of complexing agents, pH and length of extraction period on Pd solubility and its chemical transformation. Particle surface chemistry was examined using X-ray photoelectron spectroscopy (XPS) on samples treated with solutions under various conditions, including low and high O2 levels. Pd was observed to be more soluble in the presence of organic complexing agents, compared to Pt and Rh. Pd in soils was more readily solubilized with organic complexing agents compared to the model substances. After 7 days of extraction, L-methionine (0.1 M) treated soil and Pd black samples, for instance, had mean soluble Pd fractions of 12.4 ± 5.9% and 0.554 ± 0.024%, respectively. Surface chemistry analyses (XPS) confirmed the oxidation of metallic Pd surfaces when treated with organic complexing agents. The type of organic complexing agent used for experimental purposes was observed to be the most important factor influencing solubility, followed by solution pH and time of extraction. The results demonstrate that metallic Pd can be transformed into more bioaccessible species in the presence of

Evaluation method of iodine re-evolution from an in-containment water pool after a loss of coolant accident, Part I: pH estimation of a solution with various chemicals

International Nuclear Information System (INIS)

Kim, Tae Hyeon; Jeong, Ji Hwan

2016-01-01

Highlights: • It is required to evaluate re-evolved iodine from sump water after LOCA. • pH evaluation based on Gibbs free energy minimization. • Program was developed to evaluate chemical equilibrium and pH solutions. • Predictions are in good agreement with experimental data. - Abstract: Radioactive iodine, which is released into the atmosphere of the containment building, is absorbed into the containment spray water and dissolved to be ionized. This iodine-rich water is then transported to the in-containment refueling water storage tank (IRWST) in APR1400 nuclear power plants. When the pH of the water is below 7, the dissolved iodine converts to molecular iodine and re-evolves from the water and returns to the atmosphere. A series of studies have been conducted in order to evaluate the iodine re-evolution from the IRWST. This study consists of two parts: the pH evaluation method and the evaluation of the iodine re-evolution. This paper presents the first part, i.e. the pH evaluation method. The equilibrium concentrations of various chemicals in a solution are determined at the minimum Gibbs’ free energy. This method is useful for complex reactant problems rather than equilibrium constants method because the latter method requires numerous equilibrium constants and there might be missing equilibrium constants associated with the solution. The calculated pH values of solutions are compared with the experimental measurements in order to validate this method and the thermodynamic data of the chemicals incorporated into the program. The estimated values for solutions are in good agreement with the experimental measurements within a difference of less than 3.3%.

Network model of chemical-sensing system inspired by mouse taste buds.

Science.gov (United States)

Tateno, Katsumi; Igarashi, Jun; Ohtubo, Yoshitaka; Nakada, Kazuki; Miki, Tsutomu; Yoshii, Kiyonori

2011-07-01

Taste buds endure extreme changes in temperature, pH, osmolarity, so on. Even though taste bud cells are replaced in a short span, they contribute to consistent taste reception. Each taste bud consists of about 50 cells whose networks are assumed to process taste information, at least preliminarily. In this article, we describe a neural network model inspired by the taste bud cells of mice. It consists of two layers. In the first layer, the chemical stimulus is transduced into an irregular spike train. The synchronization of the output impulses is induced by the irregular spike train at the second layer. These results show that the intensity of the chemical stimulus is encoded as the degree of the synchronization of output impulses. The present algorithms for signal processing result in a robust chemical-sensing system.

76 FR 72976 - Manufacturer of Controlled Substances; Notice of Registration

Science.gov (United States)

2011-11-28

..., 2011, 76 FR 36577, Boehringer Ingelheim Chemicals, Inc., 2820 N. Normandy Drive, Petersburg, Virginia... Boehringer Ingelheim Chemicals, Inc., to manufacture the listed basic classes of controlled substances is consistent with the public interest at this time. DEA has investigated Boehringer Ingelheim Chemicals, Inc...

77 FR 15234 - Controlled Substances and List I Chemical Registration and Reregistration Fees

Science.gov (United States)

2012-03-15

...-tetrahydrocannabinol (THC), the active principle of marijuana) and synthetic cathinones (drugs of the phenethylamine... substances to illicit use. Similarly, an ever expanding number of synthetic substances, such as synthetic...

[Exposure to hazardous chemical substances in furniture industry].

Science.gov (United States)

Pośniak, Małgorzata; Kowalska, Joanna; Makhniashvili, Ivan

2005-01-01

The aim of the study was to assess the exposure to organic solvents in plants of the furniture industry. Studies were conducted in five furniture plants. Hazardous chemicals present in the air at workposts were determined by capillary gas chromatography with mass spectrometry and flame ionization detection. The analysis of air samples collected at the workposts allowed to identify the following chemicals occurring during varnishing and cleaning of furniture surface elements: acetone, butan-2-one, ethyl, isobutyl and methoxypropyl acetate, 4-methylpentan-2-on, toluene, ethylbenzene and xylenes. Indices characteristic of combined exposure ranged from 0.13 to 1.67 and exceeded the limit value at 21% of workposts. The results of the study indicate that chemicals present at representative workposts during the furniture production are harmful to health of workers, especially those involved in varnishing and cleaning of furniture elements.

Geochemical induced degradation of environmental chemicals

Energy Technology Data Exchange (ETDEWEB)

Parlar, H

1984-09-01

Attempts to correlate the concentration of organic chemicals in the environment with their production figures have resulted in a large deficit; this includes environmental chemicals such as chlorinated hydrocarbons. It has been assumed that analytical errors accounted for this deficit. Another explanation, however, allows for reactions of compounds under biotic and abiotic conditions. Because of the biostability of many organic chemicals biological transformation mechanisms can bring about slight change only. By contrast, abiotic environmental factors such as the UV-irradiation or decomposition on natural surfaces contribute considerably to the transformation of this substance class. An investigation of such abiotic charges of organic chemicals must therefore pay particular attention to dynamic and catalytic effects primarily attributable to the respective molecular state and interactions with the environment. This paper deals with the photoinduced reactions of organic substances adsorbed on natural surfaces and their significance for the degradability of environmental chemicals.

Landfill leachate treatment by coagulation/flocculation combined with microelectrolysis-Fenton processes.

Science.gov (United States)

Luo, Kun; Pang, Ya; Li, Xue; Chen, Fei; Liao, Xingsheng; Lei, Min; Song, Yong

2018-02-07

Landfill leachate was pretreated by chemical flocculation with polyaluminum chloride (PAC) as a flocculant, and subsequently purified by the microelectrolysis-Fenton (MEF) process. Response surface methodology was employed to optimize the MEF process, and the optimal conditions were initial pH 3.20, H 2 O 2 concentration 3.57 g/L, and Fe-C dosage 104.52 g/L. The PAC coagulation combined with MEF processes obtained a superior decontamination performance, and the predicted chemical oxygen demand (COD) and humic acids (HA) removal were respectively 90.27% and 93.79%. The strong fluorescence peak at 425 nm and the trapping experiment showed that [Formula: see text] was generated during MEF, which had a strong oxidation ability to degrade organic recalcitrant pollutants. The ultraviolet-visible spectra and three-dimensional excitation-emission matrices spectra (3D-EEMs) indicated that PAC coagulation could preferentially remove protein-like substances, while the MEF process was effective in destructing organic recalcitrant pollutants, especially humic-like and fulvic-like substances.

Effect of humic substances on P sorption capacity of three different soils

Science.gov (United States)

Delgado, Antonio

2010-05-01

Organic matter decreases P sorption by soils. It has been demonstrated the effect of low molecular weight compounds decreasing P adsorption on active surfaces and the effect of humic and fulvic acids inhibiting the precipitation of hydroxyapatite and favouring the formation of more soluble phosphates. This contributes to increase the recovery of applied P fertilizer. The objective of this work was to study the effect of 4 different humic substances (commercially available and provided by Tradecorp Internacional S.A.) on the sorption capacity of three soils differing widely in chemical properties (two calcareous from south Spain, pH 8 and 8.5, and other acidic from Brazil, pH 5.9 and 50 % of exchangeable basic cations). To this end, sorption isotherms were performed at a soil:0.01 M CaCl2 ratio of 1:10 at 6, 30 and 90 days. 2.5 mg of humic substances per g of soil were added to the solution. Data were fitted to the best model and linearized sorption curves for each humic substance were compared with the linearized sorption curve for the control without humic substances application (intersection point and slopes). Soil from Brazil showed a much higher sorption capacity (400 mg P kg-1 soil sorbed at 1 mg L-1 of P in the solution at 1 day) than the other two soils (50 and 100 mg P kg-1). Slow reactions significantly contributed to P sorption in the three soils, amounts sorbed at 90 days being twice than those sorbed at 1 day. Two of the products increased P sorption in the soil from Brazil at 1 day. At 90 days all the products increased P sorption significantly. This increased P sorption can be only explained by metal complexation by the substances applied, which may result in organo-metallic compounds with a high P sorption capacity. This effect was independent of the proportion of humic and fulvic acids in the applied products because the amounts of metal complexed by these compouds depend on the amount of functional groups to coordinate with metals. In the Spanish

Suicide attempts by chemicals poisoning in Colombia. 2007 - 2013

Directory of Open Access Journals (Sweden)

Viviana Calderón-Ramírez

2017-05-01

Full Text Available The objective was to set the epidemiological profile of suicide attempts by chemical substances in Colombia during the period 2007-2013. It was carried out a descriptive cross sectional study. Data were obtained from Public Health Surveillance system (SIVIGILA about poisoning chemicals 2007-2013. It was found that 55% of cases in 7 years of study corresponds to the female gender. 73% of cases occur from 10 to 29 years, with the highest concentration (31% in the group of 15 to 19. By ethnicity the Black, Afro Colombian Mulato and shows a high number of cases from 2007 to 2009 and indigenous show an upward trend from 2011 to 2013. Most people who attempt suicide are single (58% have a high school education (50% and live in municipal head. Approximately 0.05% of the women who tried to kill themselves, were in a state of pregnancy. In conclusion, a significant incidence of suicide attempts was found with chemicals, and for analysis must take into account the socio-cultural characteristics of the regions and population groups that make up the Colombian nation

Redox stability of neptunium(V) in the presence of humic substances of varying functionality

Energy Technology Data Exchange (ETDEWEB)

Schmeide, K.; Geipel, G.; Bernhard, G. [Forschungszentrum Rossendorf e.V., Institute of Radiochemistry, P.O. Box 510 119, D-01314 Dresden (Germany)

2005-07-01

Full text of publication follows: Naturally occurring aquatic humic substances (humic and fulvic acids) are known to effect the speciation and thus, the migration behavior of actinide contaminants in environmental systems due to their complexing and redox properties and their ability to form colloids. Therefore, to understand and predict the mobility of actinides in natural aquifer systems, amongst others, information on their redox stability in the presence of humic substances is necessary. In the present work, the time dependence of the reduction of Np(V) to Np(IV) by humic substances of varying functionality has been studied under anaerobic conditions between pH 3.5 and pH 9. Synthetic humic acids with pronounced redox functionality (type Cat-Gly and Hyd-Glu) [1] were studied in comparison to natural humic substances (Aldrich humic acid, Kranichsee fulvic acid). For Np speciation in solution liquid-liquid extraction, laser-induced photoacoustic spectroscopy (LIPAS), NIR absorption spectroscopy, and ultrafiltration were applied. In comparison to the natural humic substances, the synthetic humic acids lead to a much stronger reduction of Np(V) to Np(IV) [2]. The Np(IV) formed in the course of the experiments is stabilized as Np(IV) humate. The tetravalent oxidation state of Np remained constant for several months. The redox capacities of the synthetic humic acids, which are significantly higher than those of the natural humic substances, can be attributed to their higher phenolic/acidic OH group contents compared to natural humic substances. The dominating role of phenolic/acidic OH groups for the reduction of Np(V) by humic substances could be verified applying a synthetic humic acid with blocked phenolic/acidic OH groups (type Hyd-Glu-PB). Furthermore, the influence of NO{sub 3}{sup -} on the Np(V) reduction by humic substances was studied. The results have shown that by application of the synthetic humic acids with distinct redox functionalities actinides can

Taking Multiple Exposure Into Account Can Improve Assessment of Chemical Risks.

Science.gov (United States)

Clerc, Frédéric; Bertrand, Nicolas Jean Hyacinthe; La Rocca, Bénédicte

2017-12-15

During work, operators may be exposed to several chemicals simultaneously. Most exposure assessment approaches only determine exposure levels for each substance individually. However, such individual-substance approaches may not correctly estimate the toxicity of 'cocktails' of chemicals, as the toxicity of a cocktail may differ from the toxicity of substances on their own. This study presents an approach that can better take into account multiple exposure when assessing chemical risks. Almost 30000 work situations, monitored between 2005 and 2014 and recorded in two French databases, were analysed using MiXie software. The algorithms employed in MiXie can identify toxicological classes associated with several substances, based on the additivity of the selected effects of each substance. The results of our retrospective analysis show that MiXie was able to identify almost 20% more potentially hazardous situations than identified using a single-substance approach. It therefore appears essential to review the ways in which multiple exposure is taken into account during risk assessment. © The Author(s) 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

New law concerning the control of chemical substances - The end of lubricants?; Neues Chemikalienrecht. Das Ende des Schmierstoffes?

Energy Technology Data Exchange (ETDEWEB)

Baumgaertel, Stephan [Verband Schmierstoff-Industrie e.V. (VSI), Hamburg (Germany)

2010-08-15

In recent years, legal requirements on chemicals significantly changed. The introduction of REACH, GHS and the Biocidal Products Directive requires that the manufacturer of lubricants and additives as well as the end user have to fulfill a number of new obligations. This may influences the availability and diversity of lubricants due to the relatively high financial and administrative burden coming along with the new law. A reduction of diversity of substances and, ultimately, lubricant suppliers could be the result. An increased number of lubricants will be labelled as dangerous, without any change in the composition. Risk assessment changes from exposure based to a hazard based risk assessment leading to re-classification of chemicals. However, enhanced customer communication measures and new safety measures are necessary in order to fulfill the new requirements. Lubricants will not disappear from the market but the market will change radically, as outlined in this paper. (orig.)

Removal of indicator organisms by chemical treatment of wastewater.

Science.gov (United States)

De Zutter, L; van Hoof, J

1981-01-01

Recently a new chemical wastewater treatment process based upon precipitation of proteins by sodium lignosulphonate under acid conditions is used to purify the wastewater from slaughterhouses and poultry processing plants. In order to determine the reduction of indicator organisms due to this treatment process, influent and effluent samples from two of such plants (plant A in a pig slaughterhouse and plant B in a poultry processing plant) were examined. The results demonstrated that the pH used in the process, has a considerable influence on the reduction of the indicator organisms. On the first sampling day in plant A the initial working-pH was 4 and the corresponding reduction of the different microorganisms varied from 0.7 to 1.5 log. According to the decrease of the pH to 2.3, the reduction increased to a minimum of at least 1.9 and a maximum of at least 4.5 log. In the other samples from this plant (working-pH 2.4) the elimination ranged from 1.8 to 4.0 log. In plant B, the removal of the indicator organisms brought about by a working-pH of 3.0 ranged from 2.1 to 3.1 log. The results showed that in comparison with the biological treatment processes this chemical wastewater treatment process realized a significant greater removal of indicator organisms.

SWCNT-Based Biosensor Modelling for pH Detection

Directory of Open Access Journals (Sweden)

Mohammad Javad Kiani

2015-01-01

Full Text Available Different forms of CNT delivery have been discovered with several biomedical functions during past decades. The mechanisms of the cellular uptake of CNTs are mainly maintained due to the chemical nature, the cell type, and the features of the molecules, which are used to functionalize the nanotube exterior. Since single-wall carbon Nanotube (SWCNT has unique chemical and physical properties, it is a great applicant for pH sensing. In addition, ion sensitive FET (ISFET base on nanostructured SWCNT have covered a new method to help genetic investigators restructure metabolic pathways in cells, recognize the progression of disease, and expand diagnostics and therapeutics. Particularly, because PH sensing is very crucial for the constancy of enzymes, it is essential to extend the cost efficient types of this sensing. In this research, the conductance changes of the CNT-based ISFET device with different pH values can be modelled by ion concentration of the solution. In addition, the electrical current of channel is imagined as a function of pH levels, which can be controlled by a control factor (α. Thus, ISFET based nanostructured SWCNT is proposed focusing on the area of electrical detection of hydrogen ions of the electrolyte membrane. Besides, electrical detection of hydrogen ion applications is suggested to be used by modelling the delivery of SWCNT sheets. In the end, after comparing the proposed model and experimental data, it has been reported that there is a good compatibility between them.

The pH Dependence of Brown Carbon Formation in Maillard Chemistry

Science.gov (United States)

Hawkins, L. N.; Welsh, H.; Alexander, M. V.

2017-12-01

Secondary organic aerosol (SOA) composes a non-negligible fraction of brown carbon (BrC), and typically appears as small, nitrated aromatics or larger, highly functionalized humic-like substances (HULIS). Both nitrated aromatics and HULIS contain nitrogen, indicating the importance of nitrogen to light-absorbing aerosol. It is therefore unsurprising that BrC, when generated in aqueous phase reactions (aqBrC) between amines and small aldehydes, often resembles atmospheric HULIS. The effects of pH and aqueous phase oxidation on absorptivity and composition were simulated using bulk (microliter) samples under a variety of experimental conditions, including evaporation. The system of amines and small aldehydes included methylamine, ammonium sulfate, glyoxal, and methylglyoxal. Chemical composition of these products was characterized using an Aerosol Chemical Speciation Monitor (ACSM) and a desorption-based atmospheric pressure chemical ionization (APCI) spectrometer. The results of this study indicate that methylamine and methylglyoxal form the most absorptive BrC, cloud processing serves to increase BrC absorptivity, and the generated BrC is highly persistent to oxidative and photodegradation. Lowering the pH to values below 6 reduces absorptivity at shorter wavelengths, but produces a new shoulder beyond 400 nm indicating new chromophore formation. Results of this research also show that evaporation increased formation of large molecular fragments (m/z > 100). Furthermore, the mass spectra showed significant formation of these larger fragments in methylamine systems with little evidence for similar compounds in ammonium sulfate systems. Systems with methylglyoxal had higher absorptivity than all other systems, although in both methylamine and ammonium sulfate systems, glyoxal appeared to result in a higher percentage of large fragments than methylglyoxal. Lastly, hydroxyl radical degradation seemed to have a minimal effect on absorptivity and composition, although

Chemical Oscillations

Indian Academy of Sciences (India)

IMTECH),. Chandigarh. Praveen Kumar is pursuing his PhD in chemical dynamics at. Panjab University,. Chandigarh. Keywords. Chemical oscillations, autoca-. talYSis, Lotka-Volterra model, bistability, hysteresis, Briggs-. Rauscher reaction.

Influence of pH on the chemical and structural properties of the oxide films formed on 316L stainless steel, alloy 600 and alloy 690 in high temperature aqueous environments

International Nuclear Information System (INIS)

Dupin, M.; Gosser, P.; Walls, M.G.; Rondot, B.; Pastol, J.L.

2002-01-01

The oxide films formed on 316L stainless steel, alloy 600 and alloy 690 at 320 deg C in high temperature aqueous environments of different pH have been examined by glow discharge optical spectroscopy, scanning electron microscopy, atomic force microscopy and capacitance measurements. The analytical study reveals that the films formed at pH 5 are mainly composed of chromium oxides. When the pH increases the chromium concentration decreases and those of the other two elements (Ni and Fe) tend to increase. The films formed at pH 5 on 316L stainless steel and alloy 600 are thick and powder-like. The film formed at the same pH on alloy 690 is thin and is composed of a compact protective inner layer and a less-compact outer layer formed by crystals of mixed iron-nickel-chromium oxides. The morphological appearance of the thick films and that of the thin films is very different. However, equivalent morphologies can be observed for the relatively thin duplex films formed at pH 8 and pH 9.5 on the 316L stainless steel and nickel-base alloys. The evolution of the chemical composition of the films is accompanied by important changes from the point of view of their semi-conductivity. (authors)