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Sample records for acid tca precipitation

  1. Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four different WPI saccharide conjugates were successfully prepared to test whether glycation could inhibit WPI precipitation induced by trichloroacetic acid (TCA). Conjugates molecular weights after glycation were analyzed with SDS-PAGE. No significant secondary structure change due to glycation wa...

  2. Metabolism: Part II. The Tricarboxylic Acid (TCA), Citric Acid, or Krebs Cycle.

    ERIC Educational Resources Information Center

    Bodner, George M.

    1986-01-01

    Differentiates the tricarboxylic acid (TCA) cycle (or Krebs cycle) from glycolysis, and describes the bridge between the two as being the conversion of pyruvate into acetyl coenzyme A. Discusses the eight steps in the TCA cycle, the results of isotopic labeling experiments, and the net effects of the TCA cycle. (TW)

  3. Acidic precipitation

    SciTech Connect

    Martin, H.C.

    1987-01-01

    At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

  4. Genetic and biochemical interactions involving tricarboxylic acid cycle (TCA) function using a collection of mutants defective in all TCA cycle genes.

    PubMed

    Przybyla-Zawislak, B; Gadde, D M; Ducharme, K; McCammon, M T

    1999-05-01

    The eight enzymes of the tricarboxylic acid (TCA) cycle are encoded by at least 15 different nuclear genes in Saccharomyces cerevisiae. We have constructed a set of yeast strains defective in these genes as part of a comprehensive analysis of the interactions among the TCA cycle proteins. The 15 major TCA cycle genes can be sorted into five phenotypic categories on the basis of their growth on nonfermentable carbon sources. We have previously reported a novel phenotype associated with mutants defective in the IDH2 gene encoding the Idh2p subunit of the NAD+-dependent isocitrate dehydrogenase (NAD-IDH). Null and nonsense idh2 mutants grow poorly on glycerol, but growth can be enhanced by extragenic mutations, termed glycerol suppressors, in the CIT1 gene encoding the TCA cycle citrate synthase and in other genes of oxidative metabolism. The TCA cycle mutant collection was utilized to search for other genes that can suppress idh2 mutants and to identify TCA cycle genes that display a similar suppressible growth phenotype on glycerol. Mutations in 7 TCA cycle genes were capable of functioning as suppressors for growth of idh2 mutants on glycerol. The only other TCA cycle gene to display the glycerol-suppressor-accumulation phenotype was IDH1, which encodes the companion Idh1p subunit of NAD-IDH. These results provide genetic evidence that NAD-IDH plays a unique role in TCA cycle function.

  5. Acid Precipitation

    ERIC Educational Resources Information Center

    Likens, Gene E.

    1976-01-01

    Discusses the fact that the acidity of rain and snow falling on parts of the U.S. and Europe has been rising. The reasons are still not entirely clear and the consequences have yet to be well evaluated. (MLH)

  6. IRIS Toxicological Review of Trichloroacetic Acid (TCA) (Interagency Science Discussion Draft)

    EPA Science Inventory

    EPA is releasing the draft report, Toxicological Review of Trichloroacetic Acid (TCA), that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the IRIS Assessment Development ...

  7. Effects of intermediate metabolite carboxylic acids of TCA cycle on Microcystis with overproduction of phycocyanin.

    PubMed

    Bai, Shijie; Dai, Jingcheng; Xia, Ming; Ruan, Jing; Wei, Hehong; Yu, Dianzhen; Li, Ronghui; Jing, Hongmei; Tian, Chunyuan; Song, Lirong; Qiu, Dongru

    2015-04-01

    Toxic Microcystis species are the main bloom-forming cyanobacteria in freshwaters. It is imperative to develop efficient techniques to control these notorious harmful algal blooms (HABs). Here, we present a simple, efficient, and environmentally safe algicidal way to control Microcystis blooms, by using intermediate carboxylic acids from the tricarboxylic acid (TCA) cycle. The citric acid, alpha-ketoglutaric acid, succinic acid, fumaric acid, and malic acid all exhibited strong algicidal effects, and particularly succinic acid could cause the rapid lysis of Microcystis in a few hours. It is revealed that the Microcystis-lysing activity of succinic acid and other carboxylic acids was due to their strong acidic activity. Interestingly, the acid-lysed Microcystis cells released large amounts of phycocyanin, about 27-fold higher than those of the control. On the other hand, the transcription of mcyA and mcyD of the microcystin biosynthesis operon was not upregulated by addition of alpha-ketoglutaric acid and other carboxylic acids. Consider the environmental safety of intermediate carboxylic acids. We propose that administration of TCA cycle organic acids may not only provide an algicidal method with high efficiency and environmental safety but also serve as an applicable way to produce and extract phycocyanin from cyanobacterial biomass.

  8. Trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) mixture toxicity to the macrophytes Myriophyllum spicatum and Myriophyllum sibiricum in aquatic microcosms.

    PubMed

    Hanson, Mark L; Sibley, Paul K; Mabury, Scott A; Solomon, Keith R; Muir, Derek C G

    2002-02-21

    Trichloroacetic acid (TCA) and trifluoroacetic acid (TFA) have been detected together in environmental water samples throughout the world. TCA may enter into aquatic systems via rainout as the degradation product of chlorinated solvents, herbicide use, as a by-product of water disinfection and from emissions of spent bleach liquor of kraft pulp mills. Sources of TFA include degradation of hydrofluorocarbons (HFCs) refrigerants and pesticides. These substances are phytotoxic and widely distributed in aquatic environments. A study to assess the risk of a binary mixture of TCA and TFA to macrophytes in aquatic microcosms was conducted as part of a larger study on haloacetic acids. M. spicatum and M. sibiricum were exposed to 0.1, 1, 3 and 10 mg/l of both TCA and TFA (neutralized with sodium hydroxide) in replicate (n = 3) 12000 l aquatic microcosms for 49 days in an one-way analysis of variance design. Each microcosm was stocked with 14 individual apical shoots per species. The plants were sampled at regular intervals and assessed for the somatic endpoints of plant length, root growth, number of nodes and wet and dry mass and the biochemical endpoints of chlorophyll-a, chlorophyll-b, carotenoid content and citric acid levels. Results indicate that there were statistically significant effects of the TCA/TFA mixture on certain pigment concentrations immediately after the start of exposure (2-7 days), but the plants showed no signs of stress thereafter. These data suggest that TCA/TFA mixtures at environmentally relevant concentrations do not pose a significant risk to these aquatic macrophytes.

  9. Acid Precipitation; (USA)

    SciTech Connect

    Rushing, J.W.; Hicks, S.C.

    1991-01-01

    This publication, Acid Precipitation (APC) announces on a monthly basis the current worldwide information on acid precipitation and closely related subjects, including wet and dry deposition, long-range transport, environmental effects, modeling, and socioeconomic factors. Information on the following subjects is included within the scope of this publication, but all subjects may not appear in each issue: Pollution sources and pollution control technology; atmospheric transport and chemistry; terrestrial transport and chemistry; aquatic transport and chemistry; biological effects; corrosive effects; and socioeconomics, policy, and legislation.

  10. Protein precipitation of diluted samples in SDS-containing buffer with acetone leads to higher protein recovery and reproducibility in comparison with TCA/acetone approach.

    PubMed

    Santa, Cátia; Anjo, Sandra I; Manadas, Bruno

    2016-07-01

    Proteomic approaches are extremely valuable in many fields of research, where mass spectrometry methods have gained an increasing interest, especially because of the ability to perform quantitative analysis. Nonetheless, sample preparation prior to mass spectrometry analysis is of the utmost importance. In this work, two protein precipitation approaches, widely used for cleaning and concentrating protein samples, were tested and compared in very diluted samples solubilized in a strong buffer (containing SDS). The amount of protein recovered after acetone and TCA/acetone precipitation was assessed, as well as the protein identification and relative quantification by SWATH-MS yields were compared with the results from the same sample without precipitation. From this study, it was possible to conclude that in the case of diluted samples in denaturing buffers, the use of cold acetone as precipitation protocol is more favourable than the use of TCA/acetone in terms of reproducibility in protein recovery and number of identified and quantified proteins. Furthermore, the reproducibility in relative quantification of the proteins is even higher in samples precipitated with acetone compared with the original sample.

  11. Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism.

    PubMed

    Mourtzakis, M; Graham, T E; González-Alonso, J; Saltin, B

    2008-08-01

    Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops approximately 40-80% with the onset of exercise and 2-oxoglutarate declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). After 5 wk of training, peak oxygen consumption (VO2peak) in the T thigh was greater than that in the UT thigh (P<0.05); VO2peak was not different between the T and UT thighs with glutamate infusion. Peak exercise under control conditions revealed a greater glutamate uptake in the T thigh compared with rest (7.3+/-3.7 vs. 1.0+/-0.1 micromol.min(-1).kg wet wt(-1), P<0.05) without increase in TCA cycle intermediates. In the UT thigh, peak exercise (vs. rest) induced an increase in fumarate (0.33+/-0.07 vs. 0.02+/-0.01 mmol/kg dry wt (dw), P<0.05) and malate (2.2+/-0.4 vs. 0.5+/-0.03 mmol/kg dw, P<0.05) and a decrease in 2-oxoglutarate (12.2+/-1.6 vs. 32.4+/-6.8 micromol/kg dw, P<0.05). Overall, glutamate infusion increased arterial glutamate (P<0.05) and maintained this increase. Glutamate infusion coincided with elevated fumarate and malate (P<0.05) and decreased 2-oxoglutarate (P<0.05) at peak exercise relative to rest in the T thigh; there were no further changes in the UT thigh. Although glutamate may have a role in the expansion of the TCA cycle, glutamate and TCA cycle intermediates do not directly affect VO2peak in either trained or untrained muscle.

  12. Precipitation: its acidic nature.

    PubMed

    Frohliger, J O; Kane, R

    1975-08-01

    A comparison of the free hydrogen ion concentration and the total hydrogen ion concentration of rain samples shows that rain is a weak acid. The weak acid nature of rain casts doubt on the concepts that the acidity of rain is increasing and that these increases are due to strong acids such as sulfuric acid.

  13. Editorial: Acid precipitation

    SciTech Connect

    1995-09-01

    This editorial focuses on acid rain and the history of public and governmental response to acid rain. Comments on a book by Gwineth Howell `Acid Rain and Acid Waters` are included. The editor feels that Howells has provide a service to the environmental scientific community, with a textbook useful to a range of people, as well as a call for decision makers to learn from the acid rain issue and use it as a model for more sweeping global environmental issues. A balance is needed among several parameters such as level of evidence, probability that the evidence will lead to a specific direction and the cost to the global community. 1 tab.

  14. Acid Precipitation: Causes and Consequences.

    ERIC Educational Resources Information Center

    Babich, Harvey; And Others

    1980-01-01

    This article is the first of three articles in a series on the acid rain problem in recent years. Discussed are the causes of acid precipitation and its consequences for the abiotic and biotic components of the terrestrial and aquatic ecosystems, and for man-made materials. (Author/SA)

  15. Acid precipitation; an annotated bibliography

    USGS Publications Warehouse

    Wiltshire, Denise A.; Evans, Margaret L.

    1984-01-01

    This collection of 1660 bibliographies references on the causes and environmental effects of acidic atmospheric deposition was compiled from computerized literature searches of earth-science and chemistry data bases. Categories of information are (1) atmospheric chemistry (gases and aerosols), (2) precipitation chemistry, (3) transport and deposition (wet and dry), (4) aquatic environments (biological and hydrological), (5) terrestrial environments, (6) effects on materials and structures, (7) air and precipitation monitoring and data collection, and (8) modeling studies. References date from the late 1800 's through December 1981. The bibliography includes short summaries of most documents. Omitted are unpublished manuscripts, publications in press, master 's theses and doctoral dissertations, newspaper articles, and book reviews. Coauthors and subject indexes are included. (USGS)

  16. Contribution of the tricarboxylic acid (TCA) cycle and the glyoxylate shunt in Saccharomyces cerevisiae to succinic acid production during dough fermentation.

    PubMed

    Rezaei, Mohammad N; Aslankoohi, Elham; Verstrepen, Kevin J; Courtin, Christophe M

    2015-07-01

    Succinic acid produced by yeast during bread dough fermentation can significantly affect the rheological properties of the dough. By introducing mutations in the model S288C yeast strain, we show that the oxidative pathway of the TCA cycle and the glyoxylate shunt contribute significantly to succinic acid production during dough fermentation. More specifically, deletion of ACO1 and double deletion of ACO1 and ICL1 resulted in a 36 and 77% decrease in succinic acid levels in fermented dough, respectively. Similarly, double deletion of IDH1 and IDP1 decreased succinic acid production by 85%, while also affecting the fermentation rate. By contrast, double deletion of SDH1 and SDH2 resulted in a two-fold higher succinic acid accumulation compared to the wild-type. Deletion of fumarate reductase activity (FRD1 and OSM1) in the reductive pathway of the TCA cycle did not affect the fermentation rate and succinic acid production. The changes in the levels of succinic acid produced by mutants Δidh1Δidp1 (low level) and Δsdh1Δsdh2 (high level) in fermented dough only resulted in small pH differences, reflecting the buffering capacity of dough at a pH of around 5.1. Moreover, Rheofermentometer analysis using these mutants revealed no difference in maximum dough height and gas retention capacity with the dough prepared with S288C. The impact of the changed succinic acid profile on the organoleptic or antimicrobial properties of bread remains to be demonstrated.

  17. Contribution of the tricarboxylic acid (TCA) cycle and the glyoxylate shunt in Saccharomyces cerevisiae to succinic acid production during dough fermentation.

    PubMed

    Rezaei, Mohammad N; Aslankoohi, Elham; Verstrepen, Kevin J; Courtin, Christophe M

    2015-07-01

    Succinic acid produced by yeast during bread dough fermentation can significantly affect the rheological properties of the dough. By introducing mutations in the model S288C yeast strain, we show that the oxidative pathway of the TCA cycle and the glyoxylate shunt contribute significantly to succinic acid production during dough fermentation. More specifically, deletion of ACO1 and double deletion of ACO1 and ICL1 resulted in a 36 and 77% decrease in succinic acid levels in fermented dough, respectively. Similarly, double deletion of IDH1 and IDP1 decreased succinic acid production by 85%, while also affecting the fermentation rate. By contrast, double deletion of SDH1 and SDH2 resulted in a two-fold higher succinic acid accumulation compared to the wild-type. Deletion of fumarate reductase activity (FRD1 and OSM1) in the reductive pathway of the TCA cycle did not affect the fermentation rate and succinic acid production. The changes in the levels of succinic acid produced by mutants Δidh1Δidp1 (low level) and Δsdh1Δsdh2 (high level) in fermented dough only resulted in small pH differences, reflecting the buffering capacity of dough at a pH of around 5.1. Moreover, Rheofermentometer analysis using these mutants revealed no difference in maximum dough height and gas retention capacity with the dough prepared with S288C. The impact of the changed succinic acid profile on the organoleptic or antimicrobial properties of bread remains to be demonstrated. PMID:25828707

  18. Acid Precipitation and the Forest Ecosystem

    ERIC Educational Resources Information Center

    Dochinger, Leon S.; Seliga, Thomas A.

    1975-01-01

    The First International Symposium on Acid Precipitation and the Forest Ecosystem dealt with the potential magnitude of the global effects of acid precipitation on aquatic ecosystems, forest soils, and forest vegetation. The problem is discussed in the light of atmospheric chemistry, transport, and precipitation. (Author/BT)

  19. Application of citrate as a tricarboxylic acid (TCA) cycle intermediate, prevents diabetic-induced heart damages in mice

    PubMed Central

    Liang, Qianqian; Wang, Baoyu; Pang, Lingxia; Wang, Youpei; Zheng, Meiqin; Wang, Qing; Yan, Jingbin; Xu, Jinzhong

    2016-01-01

    Objective(s): Higher cellular reactive oxygen species (ROS) levels is important in reducing cellular energy charge (EC) by increasing the levels of key metabolic protein, and nitrosative modifications, and have been shown to damage the cardiac tissue of diabetic mice. However, the relation between energy production and heart function is unclear. Materials and Methods: Streptozotocin (STZ, 150 mg/kg body weight) was injected intraperitoneally once to mice that had been fasted overnight for induction of diabetes. After diabetic induction, mice received citrate (5 µg/kg) through intraperitoneal injection every other day for 5 weeks. The caspase-3, plasminogen activator inhibitor 1 (PAI1), protein kinase B (PKB), commonly known as AKT and phosphorylated-AKT (p-AKT) proteins were examined to elucidate inflammation and apoptosis in the heart. For histological analysis, heart samples were fixed with 10% formalin and stained with hematoxylin-eosin (HE) and Sirius red to assess pathological changes and fibrosis. The expression levels[AGA1] of marker proteins, tyrosine nitration, activity of ATP synthase and succinyl-CoA3-ketoacid coenzyme A transferase-1 (SCOT), and EC were measured. Results: Intraperitoneal injection of citrate significantly reduced caspase-3 and PAI-1 protein levels and increased p-AKT level on the 5th week; EC in the heart was found to be increased as well. Further, the expression level, activity, and tyrosine nitration of ATP synthase and SCOT were not affected after induction of diabetes. Conclusion: Results indicate that application of citrate, a tricarboxylic acid (TCA) cycle intermediate, might alleviate cardiac dysfunction by reducing cardiac inflammation, apoptosis, and increasing cardiac EC. PMID:27096063

  20. Optimal Concentration of 2,2,2-Trichloroacetic Acid for Protein Precipitation Based on Response Surface Methodology

    PubMed Central

    Ngo, Albert N; Ezoulin, Miezan JM; Youm, Ibrahima; Youan, Bi-Botti C

    2014-01-01

    For low protein concentrations containing biological samples (in proteomics) and for non proteinaceous compound assays (in bioanalysis), there is a critical need for a simple, fast, and cost-effective protein enrichment or precipitation method. However, 2,2,2-trichloroacetic acid (TCA) is traditionally used for protein precipitation at ineffective concentrations for very low protein containing samples. It is hypothesized that response surface methodology, can be used to systematically identify the optimal TCA concentration for protein precipitation in a wider concentration range. To test this hypothesis, a central composite design is used to assess the effects of two factors (X1 = volume of aqueous solution of protein, and X2 = volume of TCA solution 6.1N) on the optical absorbance of the supernatant (Y1), and the percentage of protein precipitated (Y2). Using either bovine serum albumin (BSA) as a model protein or human urine (with 20 ppm protein content), 4% w/v (a saddle point) is the optimal concentration of the TCA solution for protein precipitation that is visualized by SDS-PAGE analysis. At this optimal concentration, the Y2-values range from 76.26 to 92.67% w/w for 0.016 to 2 mg/mL of BSA solution. It is also useful for protein enrichment and xenobiotic analysis in protein-free supernatant as applied to tenofovir (a model HIV microbicide). In these conditions, the limit of detection and limit of quantitation of tenofovir are respectively 0.0014 mg/mL and 0.0042 mg/mL. This optimal concentration of TCA provides optimal condition for protein purification and analysis of any xenobiotic compound like tenofovir. PMID:25750762

  1. Acid precipitation and human health: Final report

    SciTech Connect

    Hoffman, S.

    1989-08-01

    This report, written for environmental managers in electric utilities, reviews potential indirect human health effects of acid precipitation. Possible exposure routes and materials examined in this review include drinking water contamination (aluminum and mercury), corrosion of metals (lead, cadmium, arsenic, selenium, copper, and zinc) and asbestos from water piping, bioaccumulation of mercury and other metals in fish and game, and uptake of mobilized metals in crops. No direct effects (e.g., skin or eye irritation) of human exposure to acid precipitation have been identified, and air pollutant impacts on health are not included in this review, because these pollutants are acid precipitation precursors, not acid precipitation per se. The literature is summarized, presenting results from researchers' studies to support their conclusions. The review discusses potential acid precipitation impacts on metal levels in drinking water and food, summarizes the health effects of ingestion of these materials, and identifies areas of needed research. Metal-metal interactions in humans that may be related to acid precipitation are identified. Current research programs and planned assessments of the indirect human health effects of acid precipitation are summarized. 136 refs., 38 figs., 17 tabs

  2. An Optimized Trichloroacetic Acid/Acetone Precipitation Method for Two-Dimensional Gel Electrophoresis Analysis of Qinchuan Cattle Longissimus Dorsi Muscle Containing High Proportion of Marbling.

    PubMed

    Hao, Ruijie; Adoligbe, Camus; Jiang, Bijie; Zhao, Xianlin; Gui, Linsheng; Qu, Kaixing; Wu, Sen; Zan, Linsen

    2015-01-01

    Longissimus dorsi muscle (LD) proteomics provides a novel opportunity to reveal the molecular mechanism behind intramuscular fat deposition. Unfortunately, the vast amounts of lipids and nucleic acids in this tissue hampered LD proteomics analysis. Trichloroacetic acid (TCA)/acetone precipitation is a widely used method to remove contaminants from protein samples. However, the high speed centrifugation employed in this method produces hard precipitates, which restrict contaminant elimination and protein re-dissolution. To address the problem, the centrifugation precipitates were first grinded with a glass tissue grinder and then washed with 90% acetone (TCA/acetone-G-W) in the present study. According to our result, the treatment for solid precipitate facilitated non-protein contaminant removal and protein re-dissolution, ultimately improving two-dimensional gel electrophoresis (2-DE) analysis. Additionally, we also evaluated the effect of sample drying on 2-DE profile as well as protein yield. It was found that 30 min air-drying did not result in significant protein loss, but reduced horizontal streaking and smearing on 2-DE gel compared to 10 min. In summary, we developed an optimized TCA/acetone precipitation method for protein extraction of LD, in which the modifications improved the effectiveness of TCA/acetone method.

  3. Effects of acid precipitation on Daphnia magna

    SciTech Connect

    Parent, S.; Cheetham, R.D.

    1980-08-01

    Pollutants derived from fossil fuel combustion and precipitated from the atmosphere have substantially increased in the past decades. These materials, precipitated in such industrialized areas as southeastern Canada, have caused considerable alterations in aquatic ecosystems. Precipitation over most of the eastern United States is presently 10 to 500 times more acidic than is natural. Most affected aquatic ecosystems contain oligotrophic waters in regions of thin poorly buffered soils. Zooplankton are an important link in food chains of aquatic ecosystems and their disappearance or decline could drastically affect trophic relationships. Declines in zooplankton density in response to acid precipitation have been reported and short term survival of Daphnia pulex between pH 4.3 and 10.4; however, its potential for reproduction was limited to a fairly narrow range. Anderson (1944) noted the advantages of using daphnia as test organisms, and concluded that Daphnia magna was representative of other abundant zooplankton in sensitivity to toxic substances.

  4. Acid neutralization of precipitation in Northern China.

    PubMed

    Wang, Yuesi; Yu, Wenpeng; Pan, Yuepeng; Wu, Dan

    2012-02-01

    There is an increasing concern over the impact of human-related emissions on the acid precipitation in China. However, few measurements have been conducted so far to clarify the acid-neutralization of precipitation on a regional scale. Under a network of 10 sites across Northern China operated during a 3-year period from December 2007 to November 2010, a total of 1118 rain and snow samples were collected. Of this total, 28% was acid precipitation with pH < 5.6. Out of these acid samples, 53% were found heavily acidic with pH value below 5.0, indicating significantly high levels of acidification of precipitation. Most of the acidity of precipitation was caused by H2SO4 and HNO3, their relative contribution being 72% and 28%, respectively. However; the contribution of HNO3 to precipitation acidity will be enhanced due to the increasing NO(x) and stable SO2 emissions in future. Neutralization factors for K+, NH4+, Ca2+, Na+, and Mg2+ were estimated as 0.06, 0.71, 0.72, 0.15, and 0.13, respectively. The application of multiple regression analysis further quantified higher NH4+ and Ca2+ contribution to the neutralization process, but the dominant neutralizing agent varied from site to site. The neutralization was less pronounced in the rural than urban areas, probably due to different levels of alkaline species, which strongly buffered the acidity. Presence of high concentrations of basic ions was mainly responsible for high pH of precipitation with annual volume-weighted mean (VWM) values larger than 5.6 at several sites. It was estimated that in the absence of buffering ions, for the given concentration of SO4(2-) and NO3-, the annual VWM pH of precipitation would have been recorded around 3.5 across Northern China. This feature suggested that emissions of particles and gaseous NH3 played very important role in controlling the spatial variations of pH of precipitation in the target areas.

  5. Primer on acid precipitation. A killing rain: the global threat of acid precipitation

    SciTech Connect

    Pawlick, T.

    1984-01-01

    This article reviews the book A Killing Rain: The Global Threat of Acid Precipitation by Thomas Pawlick which presents an overview of the problems associated with acid rain. The book covers the effects of acid rain on aquatic ecosystems, forests materials, and agriculture. It also deals with abatement technologies and sociopolitical topics associated with acid rain.

  6. NAPAP (National Acid Precipitation Assessment Program) results on acid rain

    SciTech Connect

    Not Available

    1990-06-01

    The National Acid Precipitation Assessment Program (NAPAP) was mandated by Congress in 1980 to study the effects of acid rain. The results of 10 years of research on the effect of acid deposition and ozone on forests, particularly high elevation spruce and fir, southern pines, eastern hardwoods and western conifers, will be published this year.

  7. Biologically produced acid precipitable polymeric lignin

    DOEpatents

    Crawford, Don L.; Pometto, III, Anthony L.

    1984-01-01

    A water soluble, acid precipitable polymeric degraded lignin (APPL), having a molecular weight of at least 12,000 daltons, and comprising, by percentage of total weight, at least three times the number of phenolic hydroxyl groups and carboxylic acid groups present in native lignin. The APPL may be modified by chemical oxidation and reduction to increase its phenolic hydroxyl content and reduce the number of its antioxidant inhibitory side chains, thereby improving antioxidant properties.

  8. Acid clouds and precipitation in eastern Colorado

    NASA Astrophysics Data System (ADS)

    Nagamoto, C. T.; Parungo, F.; Reinking, R.; Pueschel, R.; Gerish, T.

    Rain and snow samples were collected at the eastern foothills of the Rocky Mountains and analyzed for chemical composition. Many precipitation samples had pH values considerably more acidic than the 5.6 value of pure water containing only an equilibrium amount of atmospheric CO 2. Clear and considerable dependencies of the acidity on seasonal synoptic scale weather patterns are demonstrated. Cloud water samples, collected by aircraft over eastern Colorado, also showed low pH values. The acidity of clouds was greatest near the city of Denver.

  9. High night temperature strongly impacts TCA cycle, amino acid and polyamine biosynthetic pathways in rice in a sensitivity-dependent manner.

    PubMed

    Glaubitz, Ulrike; Erban, Alexander; Kopka, Joachim; Hincha, Dirk K; Zuther, Ellen

    2015-10-01

    Global climate change combined with asymmetric warming can have detrimental effects on the yield of crop plants such as rice (Oryza sativa L.). Little is known about metabolic responses of rice to high night temperature (HNT) conditions. Twelve cultivars with different HNT sensitivity were used to investigate metabolic changes in the vegetative stage under HNT compared to control conditions. Central metabolism, especially TCA cycle and amino acid biosynthesis, were strongly affected particularly in sensitive cultivars. Levels of several metabolites were correlated with HNT sensitivity. Furthermore, pool sizes of some metabolites negatively correlated with HNT sensitivity under control conditions, indicating metabolic pre-adaptation in tolerant cultivars. The polyamines putrescine, spermidine and spermine showed increased abundance in sensitive cultivars under HNT conditions. Correlations between the content of polyamines and 75 other metabolites indicated metabolic shifts from correlations with sugar-phosphates and 1-kestose under control to correlations with sugars and amino and organic acids under HNT conditions. Increased expression levels of ADC2 and ODC1, genes encoding enzymes catalysing the first committed steps of putrescine biosynthesis, were restricted to sensitive cultivars under HNT. Additionally, transcript levels of eight polyamine biosynthesis genes were correlated with HNT sensitivity. Responses to HNT in the vegetative stage result in distinct differences between differently responding cultivars with a dysregulation of central metabolism and an increase of polyamine biosynthesis restricted to sensitive cultivars under HNT conditions and a pre-adaptation of tolerant cultivars already under control conditions with higher levels of potentially protective compatible solutes. PMID:26208642

  10. High night temperature strongly impacts TCA cycle, amino acid and polyamine biosynthetic pathways in rice in a sensitivity-dependent manner.

    PubMed

    Glaubitz, Ulrike; Erban, Alexander; Kopka, Joachim; Hincha, Dirk K; Zuther, Ellen

    2015-10-01

    Global climate change combined with asymmetric warming can have detrimental effects on the yield of crop plants such as rice (Oryza sativa L.). Little is known about metabolic responses of rice to high night temperature (HNT) conditions. Twelve cultivars with different HNT sensitivity were used to investigate metabolic changes in the vegetative stage under HNT compared to control conditions. Central metabolism, especially TCA cycle and amino acid biosynthesis, were strongly affected particularly in sensitive cultivars. Levels of several metabolites were correlated with HNT sensitivity. Furthermore, pool sizes of some metabolites negatively correlated with HNT sensitivity under control conditions, indicating metabolic pre-adaptation in tolerant cultivars. The polyamines putrescine, spermidine and spermine showed increased abundance in sensitive cultivars under HNT conditions. Correlations between the content of polyamines and 75 other metabolites indicated metabolic shifts from correlations with sugar-phosphates and 1-kestose under control to correlations with sugars and amino and organic acids under HNT conditions. Increased expression levels of ADC2 and ODC1, genes encoding enzymes catalysing the first committed steps of putrescine biosynthesis, were restricted to sensitive cultivars under HNT. Additionally, transcript levels of eight polyamine biosynthesis genes were correlated with HNT sensitivity. Responses to HNT in the vegetative stage result in distinct differences between differently responding cultivars with a dysregulation of central metabolism and an increase of polyamine biosynthesis restricted to sensitive cultivars under HNT conditions and a pre-adaptation of tolerant cultivars already under control conditions with higher levels of potentially protective compatible solutes.

  11. Acid Precipitation: A current awareness bulletin

    SciTech Connect

    Blackburn, P.S.

    1988-01-01

    Acid Precipition (APC) announces on a monthly basis the current worldwide information on acid precipation and closely related subjects, including wet and dry deposition, long-range transport, environmental effects, modeling, and socioeconomic factors. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Data Base (EDB) during the past month. Also included are US information obtained through acquisition programs or interagency agreements and international agreements and international information obtained through the International Energy Agency's Energy Technology Data Exchange or goverment-to-government agreements.

  12. Acid precipitation. (Latest citations from the Compendex database). Published Search

    SciTech Connect

    Not Available

    1993-06-01

    The bibliography contains citations concerning the causes, effects, sources, and controls of acid precipitation and acidification. Techniques and technology for measurement and analysis of acid precipitation are considered. (Contains 250 citations and includes a subject term index and title list.)

  13. Electrostatic precipitation of condensed acid mist

    SciTech Connect

    Not Available

    1990-01-01

    This project addresses the acid mist that is formed by condensation of sulfuric acid vapor in flue gas from coal-fired utility boilers. An acid mist can be formed whenever the flue gas temperature approaches the prevailing acid dew point. This commonly occurs when the gas is subjected to rapid adiabatic cooling in a wet scrubber system for flue gas desulfurization. Acid mists can also sometimes result from unexpected temperature excursions caused by air inleakage, load cycling, and start-up operations. A wet electrostatic precipitator (WESP) is the best control option for acid mist. The mist would blind a fabric filter and attach glass fiber fabrics. A wet ESP is required because the acid would quickly corrode the plates in a conventional dry ESP. The wet ESP also offers the advantages of no rapping reentrainment and no sensitivity to fly ash resistivity. Therefore, this program has been structured around the use of a compact, wet ESP to control acid mist emissions. Progress to date is discussed. 7 refs., 1 fig.

  14. Electrostatic precipitation of condensed acid mist

    SciTech Connect

    Not Available

    1990-01-01

    This project addresses the acid mist that is formed by condensation of sulfuric acid vapor in flue gas from coal-fired utility boilers. An acid mist can be formed whenever the flue gas temperature approaches the prevailing acid dew point. This commonly occurs when the gas is subjected to rapid adiabatic cooling in a wet scrubber system for flue gas desulfurization. Acid mists can also sometimes result from unexpected temperature excursions caused by air inleakage, load cycling, and start-up operations. A wet electrostatic precipitator (WESP) is the best control option for acid mist. The mist would blind a fabric filter and attack glass fiber fabrics. A wet ESP is required because the acid would quickly corrode the plates in a conventional dry ESP. The wet ESP also offers the advantages of no rapping reentrainment and no sensitivity to fly ash resistivity. Therefore, this program has been structured around the use of a compact, wet ESP to control acid mist emissions. 7 refs.

  15. Acid precipitation. (Latest citations from Pollution Abstracts). Published Search

    SciTech Connect

    Not Available

    1992-06-01

    The bibliography contains citations concerning the wet and dry precipitation of acid, and the resultant acidification of land and water. Topics include composition, causes, effects, sources, measurements, and controls of acid precipitation. Some attention is focused upon the worldwide geographical distribution of acid precipitation and acidification. (Contains 250 citations and includes a subject term index and title list.)

  16. Acid precipitation. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    Not Available

    1994-03-01

    The bibliography contains citations concerning the research of acid precipitation, and the resultant acidification of land and water. Topics include composition, causes, effects, sources, measurements, and controls of acid precipitation. Worldwide geographical distribution of acid precipitation and acidification are covered. (Contains 250 citations and includes a subject term index and title list.)

  17. Acid precipitation. (Latest citations from Pollution Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-09-01

    The bibliography contains citations concerning the research of acid precipitation, and the resultant acidification of land and water. Topics include composition, causes, effects, sources, measurements, and controls of acid precipitation. Worldwide geographical distribution of acid precipitation and acidification are covered. (Contains 250 citations and includes a subject term index and title list.)

  18. Comment on acid precipitation in historical perspective and effects of acid precipitation

    SciTech Connect

    Richter, D.D.

    1983-01-01

    An overview is presented of the history of the problem of acid rain. Lake and stream water are classified as sensitive to acid rain largely on the basis of buffering capacity of soils and geological substrate. Evidence for acid precipitation causing the acidification of lakes and streams on a regional basis is not conclusive. However, soil genesis and forest development can be acidifying processes in humid climates. Acid rain is increasing soil aluminum solubility and leaching to surface water in concentrations toxic to fish. Under natural conditions of podzolization, aluminum is mobilized in surface soils and subsequently retained by spodic subsoils. Whether acid rain appreciably accelerates aluminum leaching from soils is hypothetical. It is concluded from one report that acid precipitation is related to increases in the accumulation and spatial variations of forest floors, soil acidification, exchangeable aluminum, aluminum released from clay, and internal ecosystem H/sup +/ ion production. But, these conclusions are based on limited sampling. 28 references.

  19. Electrostatic precipitation of condensed acid mist

    SciTech Connect

    Dahlin, R.S.

    1989-11-01

    Southern Research Institute is developing a compact, wet electrostatic precipitator (WESP) to control acid mist missions from high-sulfur coal combustion. The WESP is being developed as a retrofit technology for existing coal-fired power plants, particularly those equipped with wet flue gas desulfurization (FGD) scrubbers. Acid mist emissions can be a significant problem at these facilities because the sulfuric acid vapor in the flue gas is converted to a very fine mist that is not collected in the scrubber system. Conventional mist eliminators are not adequate in this application due to the very fine size of the mist droplets. The potential for corrosion also makes it difficult to use a fabric filter or a conventional, dry ESP in this application. Therefore, this research project has been structured around the development of a compact WESP that could be retrofit on top of an existing scrubber or within an existing flue gas duct. This paper describes the development and testing of a prototype WESP for the utility acid mist application. Testing was conducted with combustion of sulfur-doped gas to simulate the acid mist alone, and with a combination of coal and sulfur-doped gas to simulate the mixture of acid mist and fly ash downstream from a scrubber. The performance of the WESP test unit was modeled using two different cylindrical-geometry computer models: a current-seeking'' model and a current-specific'' model. 8 refs., 15 figs., 7 tabs.

  20. Comment on comment on ''acid precipitation in historical perspective and effects of acid precipitation''

    SciTech Connect

    Henriksen, A.; Richter, D.D.

    1984-01-01

    The author criticizes the fact that some soil scientists have difficulties in accepting that lakes and stream waters have become acid due to acid rain, because the natural production of acidity in ecosystems is large compared to the contribution from acid rain. He points out that Richter concludes that many of the reported changes, where real, may well result from natural processes with relatively minor contributions from acid precipitation. The author also disagrees with Krug and Frink who recently suggested that SO/sub 4/ from acid rain is exchanged with organic anions originally present in the water, leaving pH essentially unchanged. The author rebuts Henriksen who he says appears to have misunderstood the intent of the original correspondence, which was not to document evidence but rather to assert two generalities; (1) adverse effects of acid deposition on ecosystems are commonly overstated, and (2) the biogeochemistry of ecosystems is easily oversimplified, and natural sources of acidity are often ignored.

  1. Electrostatic precipitation of condensed acid mist

    SciTech Connect

    Dahlin, R.S.

    1991-04-01

    This report deals with the second part (Phase 2) of a two-phased study of the control of acid mist emissions using a compact, wet electrostatic precipitator (WESP). The goal of the study was to determine the degree of acid mist control that could be achieved when a compact WESP was used to replace or augment the mist eliminators in a flue gas desulfurization (FGD) system. Phase 1 of the study examined the electrical operation of a lab-scale WESP collecting an acid mist from a coal combustion pilot plant equipped with a spray chamber. The results of this study were used to develop and validate a computer model of the WESP. In Phase 2, measurements were made at two utility scrubber installations to determine the loadings of acid mist, fly ash, and scrubber carryover. These measurements were used as input to the computer model to project the performance of retrofitted WESPs at both of the utility test sites. Phase 1 results showed that excellent electrical operating conditions could be achieved, but very high loadings of acid mist or the fine fly ash tended to degrade electrical operation because of space charge suppression of the corona current. Measurements made at the utility sites under Phase 2 showed that acid mist accounted for 40 to 57% of the total particulate mass, while fly ash and scrubber solids accounted for 40 to 55% and 1.0 to 3.4%. Impactor samples from both test sites showed an increase in acid content with decreasing particle size. 9 refs., 14 figs., 13 tabs.

  2. Metabolic Engineering of TCA Cycle for Production of Chemicals.

    PubMed

    Vuoristo, Kiira S; Mars, Astrid E; Sanders, Johan P M; Eggink, Gerrit; Weusthuis, Ruud A

    2016-03-01

    The tricarboxylic acid (TCA) cycle has been used for decades in the microbial production of chemicals such as citrate, L-glutamate, and succinate. Maximizing yield is key for cost-competitive production. However, for most TCA cycle products, the maximum pathway yield is lower than the theoretical maximum yield (Y(E)). For succinate, this was solved by creating two pathways to the product, using both branches of the TCA cycle, connected by the glyoxylate shunt (GS). A similar solution cannot be applied directly for production of compounds from the oxidative branch of the TCA cycle because irreversible reactions are involved. Here, we describe how this can be overcome and what the impact is on the yield.

  3. Metabolic Engineering of TCA Cycle for Production of Chemicals.

    PubMed

    Vuoristo, Kiira S; Mars, Astrid E; Sanders, Johan P M; Eggink, Gerrit; Weusthuis, Ruud A

    2016-03-01

    The tricarboxylic acid (TCA) cycle has been used for decades in the microbial production of chemicals such as citrate, L-glutamate, and succinate. Maximizing yield is key for cost-competitive production. However, for most TCA cycle products, the maximum pathway yield is lower than the theoretical maximum yield (Y(E)). For succinate, this was solved by creating two pathways to the product, using both branches of the TCA cycle, connected by the glyoxylate shunt (GS). A similar solution cannot be applied directly for production of compounds from the oxidative branch of the TCA cycle because irreversible reactions are involved. Here, we describe how this can be overcome and what the impact is on the yield. PMID:26702790

  4. The influence of dust events on precipitation acidity in China

    NASA Astrophysics Data System (ADS)

    Wu, Dan; Wang, Shigong; Xia, Junrong; Meng, Xiaoyan; Shang, Kezheng; Xie, Yueyu; Wang, Ruibin

    2013-11-01

    Acid rain and dust events are both serious environmental problems striking China nowadays. This study investigates the distribution and change of precipitation pH and discusses the influence of dust events on precipitation acidity qualitatively and quantitatively in China. Acid rain exhibits remarkable regionality with strong acidic in South China and the acidity gradually decreases from the South to the North. This distribution is decided not only by the concentration of SO2 in atmosphere but also has relationship to the occurrence of dust events. Comparing the monthly changes of precipitation pH in the semiarid region (which is influenced by dust events) with those in the humid region (which is acid rain areas), it is found that the variation trends are just opposite in the two regions and there is an obvious peak value of pH in spring in semiarid region which coincides with the increase of dust event days. Chemical analysis results of precipitation in Lanzhou (a semiarid city intruded by dust events frequently, especially in spring) indicate that the ratio of Ca2+ plus Mg2+ concentrations (indicators of soil dust) to the total cation concentrations is the highest in spring, and the Ca2+ and Mg2+ concentrations are 1.8 and 1.9 times higher in spring than in summer respectively. The acidity of precipitation can be restrained by dust events qualitatively by increasing alkaline materials in the atmosphere and precipitation. The analysis of daily dust events and precipitation data at 6 stations in Northwest China indicates that the pH of precipitation influenced by dust events is greater than the precipitation not influenced by dust events. The increase degrees are different between different stations and have lagging effects. The direct increases are from 0.03 to 0.91 for the precipitation pH. Dust events can promote the precipitation pH to a certain extent quantitatively.

  5. Acid Precipitation Awareness Curriculum Materials in the Life Sciences.

    ERIC Educational Resources Information Center

    Stubbs, Harriett S.

    1983-01-01

    Provides an outline of course content for acid precipitation and two acid rain activities (introduction to pH and effects of acid rain on an organism). Information for obtaining 20 additional activities as well as an information packet containing booklets, pamphlets, and articles are also provided. (JN)

  6. Acid Precipitation in the Pacific Northwest.

    ERIC Educational Resources Information Center

    Baldwin, John; Kozak, David

    1988-01-01

    Discusses the causes, sources, and problems associated with acid deposition in the Pacific Northwest. Includes a learning activity about acid rain, "Deadly Skies," which was adapted from the Project WILD Aquatic Supplement. (TW)

  7. Viscous Design of TCA Configuration

    NASA Technical Reports Server (NTRS)

    Krist, Steven E.; Bauer, Steven X. S.; Campbell, Richard L.

    1999-01-01

    The goal in this effort is to redesign the baseline TCA configuration for improved performance at both supersonic and transonic cruise. Viscous analyses are conducted with OVERFLOW, a Navier-Stokes code for overset grids, using PEGSUS to compute the interpolations between overset grids. Viscous designs are conducted with OVERDISC, a script which couples OVERFLOW with the Constrained Direct Iterative Surface Curvature (CDISC) inverse design method. The successful execution of any computational fluid dynamics (CFD) based aerodynamic design method for complex configurations requires an efficient method for regenerating the computational grids to account for modifications to the configuration shape. The first section of this presentation deals with the automated regridding procedure used to generate overset grids for the fuselage/wing/diverter/nacelle configurations analysed in this effort. The second section outlines the procedures utilized to conduct OVERDISC inverse designs. The third section briefly covers the work conducted by Dick Campbell, in which a dual-point design at Mach 2.4 and 0.9 was attempted using OVERDISC; the initial configuration from which this design effort was started is an early version of the optimized shape for the TCA configuration developed by the Boeing Commercial Airplane Group (BCAG), which eventually evolved into the NCV design. The final section presents results from application of the Natural Flow Wing design philosophy to the TCA configuration.

  8. Effects of acid precipitation on crops

    SciTech Connect

    Lee, J.J.

    1981-01-01

    The effects of acid rain on crop yield have been studied using field-grown and potted plants. Results have shown that the chemicals in acid rain can affect crop growth and yield at ambient concentrations. For many crops, the dose-response curve probably has at least one peak and crossover point from stimulatory to inhibitory response may depend on other environmental factors. Plant parts often are affected differently, suggesting that acid rain can change the allocation of energy within plants. Available experimental results are not transferable to agricultural situations. The characteristics of acid rain which have the greatest influence on crop yield have not been determined. Interactions between acid rain and other environmental factors have scarcely been studied. Before a believable assessment of the economic impact of acid rain on crops can be done, the mechanisms of response have to be studied and the predictive capability enhanced and validated.

  9. Acid Precipitation: Scientific Progress and Public Awareness.

    ERIC Educational Resources Information Center

    Cowling, Ellis B.

    1983-01-01

    Describes certain perspectives on scientific research and on the public debates about acid deposition and its effects. Although primary attention is given to European/North American research, the ideas developed are relevant in any world region sensitive to acid deposition resulting from intense industrialization. (Author/JN)

  10. Acid precipitation. (Latest citations from the Aerospace database). Published Search

    SciTech Connect

    Not Available

    1993-12-01

    The bibliography contains citations concerning the measurement and analysis of acid rain and acidification of areas by precipitation. Both global and regionalized areas of acid rain effects are examined. Control techniques applicable to the sources and causes are discussed. (Contains a minimum of 187 citations and includes a subject term index and title list.)

  11. Electrostatic precipitation of condensed acid mist

    SciTech Connect

    Not Available

    1990-01-01

    This project addresses the problem of acid mist formed by condensation of sulfuric acid vapor in flue gas from coal-fired utility boilers. Acid mists can sometimes constitute a significant portion of the total particulate emissions from power plants burning high-sulfur coals. Complete condensation of 10 ppM of acid vapor produces a condensed acid mass loading of about 0.02 gr/dscf or 0.03 lb/MBtu, equivalent to the total allowable mass emissions under the revised (1979) New Source Performance Standards (2). The purpose of this project is to develop and demonstrated a compact, wet electrostatic collector for condensed acid mist in power plant flue gas. The project is organized in two phases. Phase I involved the WESP fabrication, laboratory and pilot combustor testing, and computer modeling. Phase II involves the solicitation of a utility demonstration site, preliminary site measurements, and planning for the demonstration test program. Only Phase II work will be addressed in this discussion which includes: site selection, site measurements, computer modeling and demonstration plan, and phase II reporting. 9 refs., 11 figs., 7 tabs.

  12. Electrostatic precipitation of condensed acid mist

    SciTech Connect

    Not Available

    1989-01-01

    The purpose of this project is to develop and demonstrate a compact, wet electrostatic collector for condensed acid mist in power plant flue gas. The following are project objectives: (1) fabrication of laboratory-version of the WESP; (2) optimization of the WESP performance through laboratory tests with a non-volatile simulant aerosol having a size distribution similar to the acid mist; (3) demonstration of adequate collection of actual acid mist in a pilot coal combustion facility under conditions simulating full-scale power plant burning high-sulfur coal; (4) development of computer model of the WESP process must be developed to assist in the process optimization, interpretation of test results, and extrapolation to full scale; and (5) solicitation of utility participation in a follow-on demonstration of the WESP concept at a full-scale power plant. The WESP fabrication, laboratory and pilot combustor testing, and computer modeling is discussed. 5 refs., 5 figs.

  13. West Virginia trout streams: target for acid precipitation

    SciTech Connect

    Gasper, D.C.

    1983-01-01

    West Virginia is greatly effected by the Ohio River Valley sources of sulfur because of the westerly winds. Estimates indicate that before 1930 the pH of precipitation was above 5.3, but now the average pH is 4.2. The effects of pollution on trout streams are discussed from two points of view. First, the streams have little ability to neutralize acid from any source, and they are very near (or below) the threshold of a trout's acid tolerance. Secondly, since stream nutrient levels are largely a product of drainage, the hypothesis is presented that if the air is cleaned up the trout streams will be lost. The increased acid activity is leaching from the soil the nutrients that are necessary to maintain the trout populations. Acid shock events are discussed in relation to water quality by acid rain. Present levels of acidity in precipitation threatens over 1/4 of West Virginia trout water with extinction.

  14. Effects of acidic precipitation on field crops

    SciTech Connect

    Evans, L.S.; Hendrey, G.R.; Lewin, K.F.; Gmur, N.F.

    1982-02-01

    The effects of acid rain on yields of field-grown soybeans has been investigated. Plants exposed to simulated rainfalls of pH 4.1, 3,3 and 2.7 had decreased seed yields of 10.6, 16.8 and 23.9% below yields of plants exposed to simulated rainfalls of pH 5.6. (ACR)

  15. Precipitation diagrams and solubility of uric acid dihydrate

    NASA Astrophysics Data System (ADS)

    Babić-Ivančić, V.; Füredi-Milhofer, H.; Brown, W. E.; Gregory, T. M.

    1987-07-01

    The solubility of uric acid dihydrate (UA·2H 2O) and the precipitation of UA·2H 2O and anhydrous uric acid (UA) from solutions containing sodium hydroxide and hydrochloric acid have been investigated. For the solubility studies, crystals of pure UA·2H 2O were prepared and equilibrated with water and with solutions of HCl or NaOH for 60 min or 20 h, respectively. The equilibrium pH (pH = 2-6.25) and uric acid concentration were determined. For the precipitation experiments, commercial UA was dissolved in NaOH in a 1:1.1 molar ratio and UA·2H 2O and/or UA were precipitated with hydrochloric acid. The precipitates and/or supernatants were examined 24 h after sample preparation. The results are represented in the form of tables, precipitation diagrams and "chemical potential" diagrams. Solubility measurements with 60 min equilibration times yielded the solubility products of UA·2H 2O, K sp(298 K) = (0.926 ± 0.025) × 10 -9mol2dm-6 and K sp(310 K) = (2.25 ± 0.05) × 10 -9mol2dm-6 and the first dissociation constants of uric acid, K 1(298 K) = (2.45 ± 0.07) × 10 -6moldm-3 and K 1(310 K) = (3.63 ± 0.08) × 10 -6moldm-3. Precipitation diagrams show that under the given experimental conditions, at 298 K, UA·2H 2O is stable for 24 h while at 310 K this was true only for precipitates formed from solutions of high supersaturations. At lower supersaturations, mixtures of UA·2H 2O and UA formed. Consequently, while the Ksp value determined from precipitation data obtained at 298 K (K sp = 1.04 × 10 -9mol2dm-6) was consistent with the respective solubility product, the 310 K precipitation boundary yielded an ion activity product, AP, the value of which fulfills the conditions Ksp(UA) < AP < Ksp (UA·2H 2O). Similar ion activity products were obtained from solubility measurements in pure water at 20 h equilibration time.

  16. Compositions and method for controlling precipitation when acidizing sour wells

    SciTech Connect

    Dill, W.R.; Walker, M.L.

    1989-12-19

    This patent describes an acidizing composition for treating a sour well. It comprises: a base acid solution having an initial ph below 1.9; an iron sequestering agent to combine with iron present in the solution comprising at least one compound selected from the group consisting of aminopolycarboxylic acids, hydroxycarboxylic acids, cyclic polyethers and derivatives of the acids and ethers present in an amount of from about 0.25 to about 5 percent by weight of the acid solution; and a sulfide modifier to combine with sulfides present in the solution comprising at least one member selected from the group consisting of an aldehyde, acetal, hemiacetal and any other compound capable of forming an aldehyde in solution, present in an amount of from about 1 to about 4 percent by weight of the acid solution, whereby precipitation of ferric hydroxide, ferrous sulfide and elemental sulfur is inhibited as acid spending occurs.

  17. Acidic precipitation: considerations for an air-quality standard

    SciTech Connect

    Evans, L.S.; Hendrey, G.R.; Stensland, G.J.; Johnson, D.W.; Francis, A.J.

    1980-01-01

    Acidic precipitation, wet or frozen deposition with a hydrogen ion concentration greatern than 2.5 ..mu..eq l/sup -1/ is a significant air pollution problem in the United States. The chief anions accounting for the hydrogen ions in rainfall are nitrate and sulfate. Agricultural systems are more likely to derive net nutritional benefits from increasing inputs of acidic rain than are forest systems when soils alone are considered. Agricultural soils may benefit because of the high N and S requirements of agricultural plants. Detrimental effects to forest soils may result if atmospheric H/sup +/ inputs significantly add to or exceed H/sup +/ production by soils. Acidification of fresh waters of southern Scandinavia, southwestern Scotland, southeastern Canada, and northeastern United States is caused by acid deposition. Areas of these regions in which this acidification occurs have in common, highly acidic precipitation with volume weighted mean annual H/sup +/ concentrations of 25 ..mu..eq l/sup -1/ or higher and slow weathering granitic or precambrian bedrock with thin soils deficient in minerals which would provide buffer capacity. Biological effects of acidification of fresh waters are detectable below pH 6.0. As lake and stream pH levels decrease below pH. 6.0, many species of plants, invertebrates, and vertebrates are progressively eliminated. Generally, fisheries are impacted below pH 5.0 and are completely destroyed below pH 4.8. There are few studies that document effects of acidic precipitation on terrestrial vegetation to establish an air quality standard. It must be demonstrated that current levels of precipitation acidity alone significantly injure terrestrial vegetation. In terms of documented damanges, current research indicates that establishing a standard for precipitation for the volume weighted annual H/sup +/ concentration at 25 ..mu..eq l/sup -1/ may protect the most sensitive areas from permanent lake acidification.

  18. Precipitation of plutonium from acidic solutions using magnesium oxide

    SciTech Connect

    Jones, S.A.

    1994-12-05

    Magnesium oxide will be used as a neutralizing agent for acidic plutonium-containing solutions. It is expected that as the magnesium oxide dissolves, the pH of the solution will rise, and plutonium will precipitate. The resulting solid will be tested for suitability to storage. The liquid is expected to contain plutonium levels that meet disposal limit requirements.

  19. Teacher's Resource Guide on Acidic Precipitation with Laboratory Activities.

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.

    The purpose of this teacher's resource guide is to help science teachers incorporate the topic of acidic precipitation into their curricula. A survey of recent junior high school science textbooks found a maximum of one paragraph devoted to the subject; in addition, none of these books had any related laboratory activities. It was on the basis of…

  20. Acidic precipitation, Vol. 2: Biological and ecological effects

    SciTech Connect

    Adriano, D.C.; Johnson, A.H.

    1989-01-01

    Acidic precipitation has its origin in emissions to the atmosphere of numerous compounds from both natural and man-made sources. The chapters in this volume cover a wide array of topics on the biological and ecological effects of acidic precipitation. A chapter on soil productivity emphasizes changes in biological and chemical characters of forest soils impacted by acidic deposition. Additional chapters discuss specific effects on soil microorganisms, trees, and crops. The importance of aluminum in this environmental issue is highlighted by a discussion on the mobility and phytotoxicity of this element in acidic soils. This chapter puts into perspective the biology of Al stressed plants. Two major chapters discuss the effect of acidic precipitation on forest ecosystems; one emphasizing North America, and the other Europe. Effects of soil acidification on key soil processes, including litter decomposition and depletion of essential plant nutrients in the soil profile are emphasized. Finally, three major chapters comprehensively cover limnological ecosystems and their response to acidic perturbation. These chapters discuss the response of stream and lake communities, both floral and faunal, to water acidification, including reduced biodiversity in these systems. Ten chapters have been processed separately for inclusion in the appropriate data bases.

  1. Acid precipitation impacts on agricultural soil management practices

    SciTech Connect

    Moskowitz, P.D.; Medeiros, W.H.; Coveney, E.A.; Lewin, K.F.; Rosenthal, R.E.

    1986-02-01

    Acid precipitation can have positive (reduced nitrogen fertilizer requirements) and negative (increased need to neutralize soil acidity) impacts on agricultural soil management practices. This paper compares the total annual deposition of nitrogen in acid precipitation with farmer applied fertilizer use and with nitrogen uptake for major crops. It also estimates the amount of lime needed to neutralize soil acidity originating from wet H/sup +/ deposition. First-order estimates indicate that the quantity of nitrogen annually deposited in the eastern US by wet acid deposition on croplands is 6% of the amount applied as fertilizer. Nitrogen deposited as wet deposition may be relatively important to unmanaged nonleguminous crops (e.g., hay) which are grown over extensive land areas. Soil acidity, which can be increased by natural (e.g., nitrogen fixation) and anthropogenic mechanisms (e.g., fertilizer application, acidic deposition) is often neutralized by the application of lime. Estimates indicate that in the eastern US, approx.2% of applied lime is used to neutralize acidity caused by wet acid deposition.

  2. Dysfunctional TCA-Cycle Metabolism in Glutamate Dehydrogenase Deficient Astrocytes.

    PubMed

    Nissen, Jakob D; Pajęcka, Kamilla; Stridh, Malin H; Skytt, Dorte M; Waagepetersen, Helle S

    2015-12-01

    Astrocytes take up glutamate in the synaptic area subsequent to glutamatergic transmission by the aid of high affinity glutamate transporters. Glutamate is converted to glutamine or metabolized to support intermediary metabolism and energy production. Glutamate dehydrogenase (GDH) and aspartate aminotransferase (AAT) catalyze the reversible reaction between glutamate and α-ketoglutarate, which is the initial step for glutamate to enter TCA cycle metabolism. In contrast to GDH, AAT requires a concomitant interconversion of oxaloacetate and aspartate. We have investigated the role of GDH in astrocyte glutamate and glucose metabolism employing siRNA mediated knock down (KD) of GDH in cultured astrocytes using stable and radioactive isotopes for metabolic mapping. An increased level of aspartate was observed upon exposure to [U-(13) C]glutamate in astrocytes exhibiting reduced GDH activity. (13) C Labeling of aspartate and TCA cycle intermediates confirmed that the increased amount of aspartate is associated with elevated TCA cycle flux from α-ketoglutarate to oxaloacetate, i.e. truncated TCA cycle. (13) C Glucose metabolism was elevated in GDH deficient astrocytes as observed by increased de novo synthesis of aspartate via pyruvate carboxylation. In the absence of glucose, lactate production from glutamate via malic enzyme was lower in GDH deficient astrocytes. In conclusions, our studies reveal that metabolism via GDH serves an important anaplerotic role by adding net carbon to the TCA cycle. A reduction in GDH activity seems to cause the astrocytes to up-regulate activity in pathways involved in maintaining the amount of TCA cycle intermediates such as pyruvate carboxylation as well as utilization of alternate substrates such as branched chain amino acids.

  3. Combined electrostatic precipitator and acidic gas removal system

    SciTech Connect

    Sparks, L.E.; Plaks, N.

    1989-12-05

    This patent describes a method of retrofitting an apparatus for removing acidic gas and particulate matter from air. The device to be retrofit including an electrostatic precipitator, lacking a precharger, positioned within a housing, a flue gas generating means outside the housing, an entry port in the housing and upstream of the electrostatic precipitator; an exit port in the housing and downstream of the electrostatic precipitator; and ductwork, outside the housing, leading from the generating means to the entry port. The retrofitting comprising the steps of: substituting electrostatic filtration units, for dry electrostatic precipitation, each comprising a precharger and a downstream particle collector having wires of from 1/4 to 1/2 inch in diameter for the electrostatic precipitator. The substituted units being designed so as to occupy less space in the housing that the electrostatic filter lacking a precharger, thereby leaving free space within the housing between a one of the prechargers which is first downstream from the entry port and the exit port and inserting an acidic gas removal means, within the housing.

  4. Mitochondrial dysfunctions in cancer: genetic defects and oncogenic signaling impinging on TCA cycle activity.

    PubMed

    Desideri, Enrico; Vegliante, Rolando; Ciriolo, Maria Rosa

    2015-01-28

    The tricarboxylic acid (TCA) cycle is a central route for oxidative metabolism. Besides being responsible for the production of NADH and FADH2, which fuel the mitochondrial electron transport chain to generate ATP, the TCA cycle is also a robust source of metabolic intermediates required for anabolic reactions. This is particularly important for highly proliferating cells, like tumour cells, which require a continuous supply of precursors for the synthesis of lipids, proteins and nucleic acids. A number of mutations among the TCA cycle enzymes have been discovered and their association with some tumour types has been established. In this review we summarise the current knowledge regarding alterations of the TCA cycle in tumours, with particular attention to the three germline mutations of the enzymes succinate dehydrogenase, fumarate hydratase and isocitrate dehydrogenase, which are involved in the pathogenesis of tumours, and to the aberrant regulation of TCA cycle components that are under the control of oncogenes and tumour suppressors. PMID:24614286

  5. Arsenic removal from acidic solutions with biogenic ferric precipitates.

    PubMed

    Ahoranta, Sarita H; Kokko, Marika E; Papirio, Stefano; Özkaya, Bestamin; Puhakka, Jaakko A

    2016-04-01

    Treatment of acidic solution containing 5g/L of Fe(II) and 10mg/L of As(III) was studied in a system consisting of a biological fluidized-bed reactor (FBR) for iron oxidation, and a gravity settler for iron precipitation and separation of the ferric precipitates. At pH 3.0 and FBR retention time of 5.7h, 96-98% of the added Fe(II) precipitated (99.1% of which was jarosite). The highest iron oxidation and precipitation rates were 1070 and 28mg/L/h, respectively, and were achieved at pH 3.0. Subsequently, the effect of pH on arsenic removal through sorption and/or co-precipitation was examined by gradually decreasing solution pH from 3.0 to 1.6 (feed pH). At pH 3.0, 2.4 and 1.6, the highest arsenic removal efficiencies obtained were 99.5%, 80.1% and 7.1%, respectively. As the system had ferric precipitates in excess, decreased arsenic removal was likely due to reduced co-precipitation at pH<2.4. As(III) was partially oxidized to As(V) in the system. In shake flask experiments, As(V) sorbed onto jarosite better than As(III). Moreover, the sorption capacity of biogenic jarosite was significantly higher than that of synthetic jarosite. The developed bioprocess simultaneously and efficiently removes iron and arsenic from acidic solutions, indicating potential for mining wastewater treatment. PMID:26705889

  6. Acidic precipitation: a technical amplification of NAPAP's findings

    SciTech Connect

    Lefohn, A.S.; Krupa, S.V.

    1988-06-01

    In September 1987, NAPAP released a 4-volume, 925 page interim report that summarized the effects of acidic precipitation on crops, forests, aquatic ecosystems, visibility, and human health. Following the release of the report, APCA coordinated an international conference to provide a forum for the technical amplification of the conclusions reached in NAPAP's report. Scientists from the United States and Canada were invited to participate in the conference. The focus of the meeting was concerned only with the technical aspects of the NAPAP report. At the conference, there were important research concepts presented that may require further attention before definitive, bottom line statements can be made concerning the effects of acid precipitation on the environment. The purpose of this paper is to summarize the key technical points made at the conference and provide NAPAP with additional scientific inputs as it begins to prepare for its 1990 Final Assessment Report.

  7. Precipitation polymerization of acrylic acid in supercritical carbon dioxide

    SciTech Connect

    Romack, T.J.; Maury, E.E.; DeSimone, J.M.

    1995-02-13

    Increasing concern regarding the dissemination of chemical waste (both aqueous and organic) into their environment has prompted considerable interest in new technologies aimed at reducing current waste streams. Processes utilizing carbon dioxide in lieu of conventional solvents for chemical manufacturing and processing provide a viable route to achieving near-zero waste production for these important industries. The authors report the successful precipitation polymerization of acrylic acid in supercritical carbon dioxide at pressure ranging from 125 to 345 bar utilizing AIBN as a free radical initiator. Analyses by gel permeation chromatography (GPC) and scanning electron microscopy (SEM) indicate that for the pressure range studied there is no appreciable effect on product molecular weight, molecular weight distribution, or particle size or morphology. In addition, effective molecular weight control was demonstrated for precipitation polymerizations of acrylic acid in CO{sub 2} through the use of ethyl mercaptan as a chain transfer agent.

  8. Impact of effects of acid precipitation on toxicity of metals.

    PubMed

    Nordberg, G F; Goyer, R A; Clarkson, T W

    1985-11-01

    Acid precipitation may increase human exposure to several potentially toxic metals by increasing metal concentrations in major pathways to man, particularly food and water, and in some instances by enhancing the conversion of metal species to more toxic forms. Human exposures to methylmercury are almost entirely by way of consumption of fish and seafood. In some countries, intakes by this route may approach the levels that can give rise to adverse health effects for population groups with a high consumption of these food items. A possible increase in methylmercury concentrations in fish from lakes affected by acid precipitation may thus be of concern to selected population groups. Human exposures to lead reach levels that are near those associated with adverse health effects in certain sensitive segments of the general population in several countries. The possibility exists that increased exposures to lead may be caused by acid precipitation through a mobilization of lead from soils into crops. A route of exposure to lead that may possibly be influenced by acid precipitation is an increased deterioration of surface materials containing lead and a subsequent ingestion by small children. A similar situation with regard to uptake from food exists for cadmium (at least in some countries). Human metal exposures via drinking water may be increased by acid precipitation. Decreasing pH increases corrosiveness of water enhancing the mobilization of metal salts from soil; metallic compounds may be mobilized from minerals, which may eventually reach drinking water. Also, the dissolution of metals (Pb, Cd, Cu) from piping systems for drinking water by soft acidic waters of high corrosivity may increase metal concentrations in drinking water. Exposures have occasionally reached concentrations which are in the range where adverse health effects may be expected in otherwise healthy persons. Dissolution from piping systems can be prevented by neutralizing the water before

  9. Acid precipitation--effects on trace elements and human health.

    PubMed

    Gerhardsson, L; Oskarsson, A; Skerfving, S

    1994-08-22

    Environmental pollution by acid precipitation increases the solubilization and mobilization of toxic metals. Through the food chain, this may alter the intake of toxic and essential elements in man. Potential adverse health effects could follow after increased human exposure. For the general population, the exposure pattern and health effects caused by aluminium, cadmium, lead and mercury are of particular concern. Although there are several indications that the exposure to toxic elements (e.g. aluminium, cadmium, lead and methylmercury), as well as the intake of essential elements (e.g. selenium), may be affected by acid precipitation, there is presently no firm evidence of adverse health effects in man. However, the present data clearly indicate that the safety margins are small. Thus, the ongoing acidification in many areas must be stopped before such effects become evident. The effects on trace element status and human health by acid precipitation were discussed at the ISTERH (International Society for Trace Element Research in Humans) Conference in Stockholm, May, 1992. The main findings are briefly summarized here.

  10. Ten-year study on acid precipitation nears conclusion

    SciTech Connect

    Olem, H. )

    1990-04-01

    Results from the National Acid Precipitation Assessment Program (NAPAP) are discussed. Final results are contained in 26 state of the science reports. Seven of the reports provide information on acid rain and aquatic ecosystems. They describe the current state of acidic surface waters, watershed processes affecting surface water chemistry, historical evidence for surface water acidification, methods for forecasting future changes, and the response of acidic surface water to liming. Six areas of the country were found to be of special interest: southwest Adirondacks, New England, forested areas of the mid-Atlantic highlands, the Atlantic coastal plain, the northern Florida highlands, parts of northeastern Wisconsin and the Upper Peninsula of Michigan. Environmental effects, mitigation efforts and possible legislation are briefly discussed.

  11. Precipitation of plutonium from acidic solutions using magnesium oxide

    SciTech Connect

    Jones, S.A.

    1994-09-06

    Plutonium (IV) is only marginally soluble in alkaline solution. Precipitation of plutonium using sodium or potassium hydroxide to neutralize acidic solutions produces a gelatinous solid that is difficult to filter and an endpoint that is difficult to control. If the pH of the solution is too high, additional species precipitate producing an increased volume of solids separated. The use of magnesium oxide as a reagent has advantages. It is added as a solid (volume of liquid waste produced is minimized), the pH is self-limiting (pH does not exceed about 8.5), and the solids precipitated are more granular (larger particle size) than those produced using KOH or NaOH. Following precipitation, the raffinate is expected to meet criteria for disposal to tank farms. The solid will be heated in a furnace to dry it and convert any hydroxide salts to the oxide form. The material will be cooled in a desiccator. The material is expected to meet vault storage criteria.

  12. Potential impact of acid precipitation on arsenic and selenium.

    PubMed Central

    Mushak, P

    1985-01-01

    The potential impact of acidic precipitation on the environmental mobility of the metalloids arsenic (As) and selenium (Se) has not been given much attention and is poorly understood. As with other elements, the interest here is the potential effect of environmental acidification on environmental behavior in ways that are relevant to human exposure to these metalloids. Available information on acid precipitation and the environmental behavior of these metalloids do, however, permit some preliminary conclusions to be drawn. Both As and Se appear to be mobilized from household plumbing into tap water by the corrosive action of soft, mildly acidic water, while surface water catchment systems in areas impacted by acidic deposition may contain elevated soluble As levels. Acidification of aquatic ecosystems that are drinking water sources may pose the prospect of enhanced release of As from sediment to water as well as reduction in water levels of Se. Acidification of ground waters, where As appears to be especially mobile, is of particular concern in this regard. The potential impact of acidic deposition on As and Se in soils cannot readily be assessed with respect to human exposure, but it would appear that the behavior of these metalloids in poorly buffered, poorly immobilizing soils, e.g., sandy soils of low metal hydrous oxide content, would be most affected. The effect is opposite for the two elements; lowered pH would appear to enhance As mobility and to reduce Se availability. Altered acidity of both soil and aquatic systems poses a risk for altered biotransformation processes involving both As and Se, thereby affecting the relative amounts of different chemical forms varying in their toxicity to humans as well as influencing biogeochemical cycling. PMID:4076075

  13. Potential impact of acid precipitation on arsenic and selenium.

    PubMed

    Mushak, P

    1985-11-01

    The potential impact of acidic precipitation on the environmental mobility of the metalloids arsenic (As) and selenium (Se) has not been given much attention and is poorly understood. As with other elements, the interest here is the potential effect of environmental acidification on environmental behavior in ways that are relevant to human exposure to these metalloids. Available information on acid precipitation and the environmental behavior of these metalloids do, however, permit some preliminary conclusions to be drawn. Both As and Se appear to be mobilized from household plumbing into tap water by the corrosive action of soft, mildly acidic water, while surface water catchment systems in areas impacted by acidic deposition may contain elevated soluble As levels. Acidification of aquatic ecosystems that are drinking water sources may pose the prospect of enhanced release of As from sediment to water as well as reduction in water levels of Se. Acidification of ground waters, where As appears to be especially mobile, is of particular concern in this regard. The potential impact of acidic deposition on As and Se in soils cannot readily be assessed with respect to human exposure, but it would appear that the behavior of these metalloids in poorly buffered, poorly immobilizing soils, e.g., sandy soils of low metal hydrous oxide content, would be most affected. The effect is opposite for the two elements; lowered pH would appear to enhance As mobility and to reduce Se availability. Altered acidity of both soil and aquatic systems poses a risk for altered biotransformation processes involving both As and Se, thereby affecting the relative amounts of different chemical forms varying in their toxicity to humans as well as influencing biogeochemical cycling.

  14. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream-flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid-forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Streamwater pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by calcium, magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southeast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site.

  15. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Stream water pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southwast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site. 10 references, 2 tables.

  16. Fluxes and reservoirs of trichloroacetic acid at a forest and moorland catchment.

    PubMed

    Stidson, R T; Dickey, C A; Cape, J N; Heal, K V; Heal, M R

    2004-03-15

    The concentrations and input/output fluxes of trichloroacetic acid (TCA) were measured in all relevant media for one year at a 0.86 km2 upland conifer plantation and moorland catchment in SW Scotland (n > 380 separate samples analyzed). Annual wet precipitation to the catchment was 2.5 and 0.4 m for rain and cloud, respectively. TCA input to the catchment for the year was 2100 g, predominantly in rainwater (86%), with additional input via cloudwater (13%) and gas plus particle dry deposition (1%). There were no seasonal trends in TCA deposition, and cloudwater concentration was not enhanced over rainwater. TCA in precipitation exceeded concentrations estimated using currently accepted routes of gas-phase oxidation from anthropogenic chlorinated hydrocarbon precursors, in agreement with previous studies. Export of TCA from the catchment in streamwater totalled 1970 g for the year of study. The TCA concentration in streamwater at outflow (median 1.2 microg L(-1)) was significantly greater than that before the stream had passed through the conifer plantation. To well-within measurement uncertainties, the catchment is currently at steady-state with respect to TCA input/output. The catchment reservoir of TCA was dominated by soils (approximately 90%), with the remainder distributed in forest litter (approximately 9%), forest branchwood and stemwood (approximately 0.7%), forest foliage (approximately 0.5%), and moorland foliage (approximately 0.1%). Although TCA is clearly taken up into foliage, which consequently may be important for the vegetation, this was a relatively minor process for TCA at the catchment scale. If it is assumed, on the basis of laboratory extraction experiments, that only approximately 20% of "whole soil" TCA measured in this work was water extractable, then total mass of TCA in the catchment is reduced from approximately 13 to approximately 3.5 kg. Comparing the latter value with the annual flux yields an average steady-state residence time for

  17. Fluxes and reservoirs of trichloroacetic acid at a forest and moorland catchment.

    PubMed

    Stidson, R T; Dickey, C A; Cape, J N; Heal, K V; Heal, M R

    2004-03-15

    The concentrations and input/output fluxes of trichloroacetic acid (TCA) were measured in all relevant media for one year at a 0.86 km2 upland conifer plantation and moorland catchment in SW Scotland (n > 380 separate samples analyzed). Annual wet precipitation to the catchment was 2.5 and 0.4 m for rain and cloud, respectively. TCA input to the catchment for the year was 2100 g, predominantly in rainwater (86%), with additional input via cloudwater (13%) and gas plus particle dry deposition (1%). There were no seasonal trends in TCA deposition, and cloudwater concentration was not enhanced over rainwater. TCA in precipitation exceeded concentrations estimated using currently accepted routes of gas-phase oxidation from anthropogenic chlorinated hydrocarbon precursors, in agreement with previous studies. Export of TCA from the catchment in streamwater totalled 1970 g for the year of study. The TCA concentration in streamwater at outflow (median 1.2 microg L(-1)) was significantly greater than that before the stream had passed through the conifer plantation. To well-within measurement uncertainties, the catchment is currently at steady-state with respect to TCA input/output. The catchment reservoir of TCA was dominated by soils (approximately 90%), with the remainder distributed in forest litter (approximately 9%), forest branchwood and stemwood (approximately 0.7%), forest foliage (approximately 0.5%), and moorland foliage (approximately 0.1%). Although TCA is clearly taken up into foliage, which consequently may be important for the vegetation, this was a relatively minor process for TCA at the catchment scale. If it is assumed, on the basis of laboratory extraction experiments, that only approximately 20% of "whole soil" TCA measured in this work was water extractable, then total mass of TCA in the catchment is reduced from approximately 13 to approximately 3.5 kg. Comparing the latter value with the annual flux yields an average steady-state residence time for

  18. Precipitation of biomimetic fluorhydroxyapatite/polyacrylic acid nanostructures

    NASA Astrophysics Data System (ADS)

    Roche, Kevin J.; Stanton, Kenneth T.

    2015-01-01

    Ordered structures of fluorhydroxyapatite (FHA) nanoparticles that resemble the nanostructure of natural human enamel have been prepared. Wet precipitation in the presence of polyacrylic acid (PAA) was used, and the particle morphology was altered by varying several reaction conditions. High molecular weight PAA increased particle length from around 54 nm to several hundred nanometres, while maintaining particle width at 15 nm. PAA concentration and the order of mixing the reactants also influenced crystal morphology. Optimum conditions produced dense, aligned bundles of highly elongated nanorods, which are very similar to the hierarchical nanostructure of human tooth enamel.

  19. Acid precipitation and embryonic mortality of spotted salamanders, Ambystoma maculatum.

    PubMed

    Pough, F H

    1976-04-01

    Spotted salamanders breed in temporary pools formed in early spring by melted snow and rain. Many of these pools reflect the low pH of precipitation in the northeastern United States. Egg mortality is low (less than 1 percent) in pools near neutrality, but high (greater than 60 percent) in pools more acid than pH 6. Developmental anomalies and the embryonic stage at which death occurs are the same in field situations as at corresponding pH's in laboratory experiments.

  20. MicroTCA and AdvancedTCA equipment evaluation and customization for LHC experiments

    NASA Astrophysics Data System (ADS)

    Di Cosmo, M.; Bobillier, V.; Haas, S.; Joos, M.; Mico, S.; Vasey, F.

    2015-01-01

    The MicroTCA and AdvancedTCA industry standards are candidate modular electronics platforms for the upgrade of the current generation of high energy physics experiments at CERN. The PH-ESE group at CERN launched an xTCA evaluation project with the aim of performing technical evaluations and providing support for commercially available components. Over the past years, different equipment from different vendors has been acquired and evaluated. This paper summarizes our evaluation results of commercial MicroTCA and AdvancedTCA equipment. Special emphasis is put on the component requirements to be defined in view of future equipment procurement. Customized prototypes developed according to these generic specifications are presented for the first time.

  1. ATCA/μTCA for physics

    NASA Astrophysics Data System (ADS)

    Jezynski, Tomasz; Larsen, Raymond; Le Du, Patrick

    2010-11-01

    ATCA/μTCA platforms are attractive because of the modern serial link architecture, high availability features and many packaging options. Less-demanding availability applications can be met economically by scaling back speed and redundancy. The ATCA specification was originally targeted for the Telecom industry but has gained recently a much wider user audience. The purpose of this paper is to report on present hardware and software R&D efforts where ATCA and μTCA are planned, already being used or in development using selected examples for accelerator and detectors in the Physics community. It will present also the status of a proposal for physics extensions to ATCA/μTCA specifications to promote inter-operability of laboratory and industry designs for physics.

  2. Impact of acid precipitation on recreation and tourism in Ontario: an overview

    SciTech Connect

    Not Available

    1984-01-01

    The impacts of acid precipitation on fishing opportunities, waterfowl and moose hunting, water contact activities, and the perception of the environment in Ontario are analyzed. Economic effects and future research needs are also estimated and discussed. These questions have been examined by identifying the likely links between acidic precipitation and recreation and tourism, by developing estimates of the importance of aquatic-based recreation and tourism, by describing the current and estimated future effects of acid precipitation. 101 references, 9 figures, 19 tables.

  3. Effects of precipitation on soil acid phosphatase activity in three successional forests in Southern China

    NASA Astrophysics Data System (ADS)

    Huang, W.; Liu, J.; Zhou, G.; Zhang, D.; Deng, Q.

    2011-01-01

    Phosphorus (P) is often a limiting nutrient for plant growth in tropical and subtropical forests. Global climate change has led to alterations in precipitation in the recent years, which inevitably influences P cycling. Soil acid phosphatase plays a vital role in controlling P mineralization, and its activity reflects the capacity of P supply to ecosystems. In order to study the effects of precipitation on soil acid phosphatase activity, an experiment of precipitation treatments (no precipitation, natural precipitation and doubled precipitation) in three forests of early-, mid- and advanced-successional stages in Southern China was carried out. Results showed that driven by seasonality of precipitation, changes in soil acid phosphatase activities coincided with the seasonal climate pattern, with significantly higher values in the wet season than in the dry season. Soil acid phosphatase activities were closely linked to forest successional stages, with enhanced values in the later stages of forest succession. In the dry season, soil acid phosphatase activities in the three forests showed a rising trend with increasing precipitation treatments. In the wet season, no precipitation treatment depressed soil acid phosphatase activity, while doubled precipitation treatment exerted no positive effects on it, and even significantly lowered it in the advanced forest. These indicate the potential transformation rate of organic P might be more dependent on water in the dry season than in the wet season. The negative responses of soil acid phosphatase activity to precipitation suggest that P supply in subtropical ecosystems might be reduced if there was a drought in a whole year or more rainfall in the wet season in the future. NP, no precipitation; Control, natural precipitation; DP, double precipitation.

  4. Occurrence of acid precipitation on the West Coast of the United States

    SciTech Connect

    Powers, C.F.; Rambo, D.L.

    1981-01-01

    Compilation of published and unpublished data shows acid precipitation to be more widespread in the Pacific coastal states than is generally recognized. Although information is scattered and discontinuous, precipitation is definitely acidic in the Los Angeles Basin and north-central California and in the Puget Sound region in Washington. Acid-rain occurrences were observed in western and eastern Oregon, but data are inadequate for regional generalization. New stations currently being established in Washington and Oregon, largely in response to the recently renewed activity of Mount St. Helens, will greatly facilitate assessment of precipitation acidity in the Northwest.

  5. The occurrence of acid precipitation on the west coast of the United States.

    PubMed

    Powers, C F; Rambo, D L

    1981-06-01

    Compilation of published and unpublished data shows acid precipitation to be more widespread in the Pacific coastal states than is generally recognized. Although information is scattered and discontinuous, precipitation is definitely acidic in the Los Angeles Basin and north-central california, and in the Puget Sound region in Washington. Acid rain occurrences have been observed in western and eastern Oregon, but data are inadequate for regional generalization. New stations currently being established in Washington and Oregon, largely in resposnse to the recently renewed activity of Mount St. Helens, will greatly facilitate assessment of precipitation acidity in the Northwest.

  6. Fluxes of trichloroacetic acid through a conifer forest canopy.

    PubMed

    Stidson, R T; Heal, K V; Dickey, C A; Cape, J N; Heal, M R

    2004-11-01

    Controlled-dosing experiments with conifer seedlings have demonstrated an above-ground route of uptake for trichloroacetic acid (TCA) from aqueous solution into the canopy, in addition to uptake from the soil. The aim of this work was to investigate the loss of TCA to the canopy in a mature conifer forest exposed only to environmental concentrations of TCA by analysing above- and below-canopy fluxes of TCA and within-canopy instantaneous reservoir of TCA. Concentrations and fluxes of TCA were quantified for one year in dry deposition, rainwater, cloudwater, throughfall, stemflow and litterfall in a 37-year-old Sitka spruce and larch plantation in SW Scotland. Above-canopy TCA deposition was dominated by rainfall (86%), compared with cloudwater (13%) and dry deposition (1%). On average only 66% of the TCA deposition passed through the canopy in throughfall and stemflow (95% and 5%, respectively), compared with 47% of the wet precipitation depth. Consequently, throughfall concentration of TCA was, on average, approximately 1.4 x rainwater concentration. There was no significant difference in below-canopy fluxes between Sitka spruce and larch, or at a forest-edge site. Annual TCA deposited from the canopy in litterfall was only approximately 1-2% of above-canopy deposition. On average, approximately 800 microg m(-2) of deposited TCA was lost to the canopy per year, compared with estimates of above-ground TCA storage of approximately 400 and approximately 300 microg m(-2) for Sitka spruce and larch, respectively. Taking into account likely uncertainties in these values ( approximately +/- 50%), these data yield an estimate for the half-life of within-canopy elimination of TCA in the range 50-200 days, assuming steady-state conditions and that all TCA lost to the canopy is transferred into the canopy material, rather than degraded externally. The observations provide strong indication that an above-ground route is important for uptake of TCA specifically of atmospheric

  7. MicroTCA and AdvancedTCA equipment evaluation and developments for LHC experiments

    NASA Astrophysics Data System (ADS)

    Bobillier, V.; Haas, S.; Joos, M.; Mendez, J.; Mico, S.; Vasey, F.

    2016-02-01

    The MicroTCA (MTCA) and AdvancedTCA (ATCA) industry standards have been selected as the platform for many of the current and planned upgrades of the off-detector electronic systems of two of the LHC experiments at CERN. We present a status update from an ongoing project to evaluate commercial MTCA and ATCA components with particular emphasis on infrastructure equipment such as shelves and power-supplies. Shelves customized for use in the existing LHC rack infrastructure have been tested, and electrical and cooling measurements and simulations were performed. In-house developments for hardware platform management will also be shown.

  8. National Acid Precipitation Assessment Program: Acidic deposition: An inventory of non-Federal research, monitoring, and assessment information

    SciTech Connect

    Herrick, C.N.

    1990-01-01

    The Acid Precipitation Act of 1990 (Title VII of the Energy Security Act of 1980, P.L. 96-294) established the Interagency Task Force on Acid Precipitation to develop and implement the National Acid Precipitation Assessment Program (NAPAP). The information included in the document was provided to NAPAP's Task Group Leaders and State-of-Science and State-of-Technology authors in July 1989. The early release was intended to assure that the authors would be aware of the information at an early phase in the assessment production process.

  9. Atmospheric concentrations and deposition of trichloroacetic acid in Scotland: results from a 2-year sampling campaign.

    PubMed

    Heal, M R; Reeves, N M; Cape, J N

    2003-06-15

    The first long-term concurrent measurements of trichloroacetic acid (TCA) in rainwater, in cloudwater, and in air (both gas and particle phase) are reported. Measurements were made weekly between June 1998 and April 2000 at a rural forested upland site in SE Scotland. Rainwater TCA concentration did not differ significantly between two elevations (602 and 275 m asl), with precipitation-weighted mean values of 0.77 and 0.70 microg L(-1), respectively (n > 75). The precipitation-weighted mean concentration of TCA in cloudwater at the highest elevation was 0.92 microg L(-1), yielding an average cloudwater enrichment factor of 1.2, considerably lower than for other inorganic ions measured. Rainwater and cloudwater TCA concentrations did not vary systematically with season. Since wet precipitation depth also did not vary systematically with season, the wet deposition fluxes of TCA were likewise invariant (annual fluxes at the highest elevation of 880 and 130 microg m(-2), respectively, for rain and cloud interception to spruce forest). Weekly integrated concentrations of TCA in air (gas and particle) were very low (median 25 pg m(-3), range < LOD-110 pg m(-3)). The estimated upper limit for annual dry deposition of TCA at this site was approximately 20 microg m(-2), assuming a deposition velocity of 2 cm s(-1). Concentrations of TCA in air correlated reasonably strongly with concentrations in rainwater, with a partition ratio approximately equal to the Henry's law coefficient. On average, only about 23% of TCA measured in Edinburgh air was associated with the particle phase. These measurements are consistent with the observed high scavenging ratio of TCA (ratio of concentration in air to concentration in rainwater). Overall, these data confirm that the atmosphere is an important source of TCA to the environment and that precipitation is the dominant transfer mechanism. In line with previous work, the atmospheric deposition flux is greater than expected from the current

  10. Effects of precipitation on soil acid phosphatase activity in three successional forests in southern China

    NASA Astrophysics Data System (ADS)

    Huang, W.; Liu, J.; Zhou, G.; Zhang, D.; Deng, Q.

    2011-07-01

    Phosphorus (P) is often a limiting nutrient for plant growth in tropical and subtropical forests. Global climate change has led to alterations in precipitation in the recent years, which inevitably influences P cycling. Soil acid phosphatase plays a vital role in controlling P mineralization, and its activity reflects the capacity of organic P mineralization potential in soils. In order to study the effects of precipitation on soil acid phosphatase activity, an experiment with precipitation treatments (no precipitation, natural precipitation and doubled precipitation) in three successional forests in southern China was carried out. The three forests include Masson pine forest (MPF), coniferous and broad-leaved mixed forest (MF) and monsoon evergreen broad-leaved forest (MEBF). Results showed that driven by seasonality of precipitation, changes in soil acid phosphatase activities coincided with the seasonal climate pattern, with significantly higher values in the wet season than in the dry season. Soil acid phosphatase activities were closely linked to forest successional stages, with enhanced values in the later stages of forest succession. In the dry season, soil acid phosphatase activities in the three forests showed a rising trend with increasing precipitation treatments. In the wet season, soil acid phosphatase activity was depressed by no precipitation treatment in the three forests. However, doubled precipitation treatment exerted a significantly negative effect on it only in MEBF. These results indicate that the potential transformation rate of organic P might be more dependent on water in the dry season than in the wet season. A decrease in organic P turnover would occur in the three forests if there was a drought in a whole year in the future. More rainfall in the wet season would also be adverse to organic P turnover in MEBF due to its high soil moisture.

  11. Acid-Base and Precipitation Equilibria in Wine

    ERIC Educational Resources Information Center

    Palma, Miguel; Barroso, Carmelo G.

    2004-01-01

    Experiments are performed to establish the changes of pH during the precipitation of potassium hydrogen tartrate, with its unfavorable impact on the stability of wine. Students, thus, obtain a clearer understanding of the interplay between a variety of chemical equilibria within a single medium.

  12. Compositions and method for controlling precipitation when acidizing sour wells

    SciTech Connect

    Dill, W.R.; Walker, M.L.

    1990-08-21

    This patent describes a method of treating a sour well penetrating a subterranean formation. It comprises: introducing into the well a treating fluid comprising an acid solution having a pH below 1.9, an iron sequestering agent comprising at least one compound selected from the group consisting of aminopolycarboxylic acids, hydroxycarboxylic acids, cyclic polyethers and derivatives of the acids and ethers, present in an amount of from about 0.25 to about 5 percent by weight of the acid solution, and a sulfide modifier comprising at least one compound selected from the group consisting of an aldehyde, acetal, hemiacetal and any other compound capable of forming aldehydes in the acid solution, present in an amount of from about 0.25 to about 5 percent of the acid solution; and treating the subterranean formation with the treating fluid.

  13. National Acid Precipitation Assessment Program annual report, 1988, to the President and Congress

    SciTech Connect

    Not Available

    1989-01-13

    The Acid Precipitation Act of 1980 (Title VII of the Energy Security Act of 1980, Public Law 96-294) established the Interagency Task Force on Acid Precipitation to develop and implement the National Acid Precipitation Assessment Program (NAPAP). The purpose of NAPAP is to increase the authors understanding of the causes and effects of acidic deposition, and to produce scientific information to support decisionmaking regarding acidic deposition control and abatement strategies. The Report, the Program's seventh, is divided into three major sections. The first section describes the Program's organizational structure, external coordination activities, peer reviews, and budgetary status. It also includes a discussion of the NAPAP assessment process, and provides a synopsis of NAPAP's plan and schedule for 1989 and 1990 assessment reports.

  14. Ecological effects of acid precipitation on primary producers

    SciTech Connect

    Conway, H.L.; Hendrey, G.R.

    1981-01-01

    Non-acidic, oligotrophic lakes are typically dominated by golden-brown algae, diatoms and green algae. With increasing acidity, the number of species decrease and the species composition changes to dinoflagellates and golden-brown algae, with blue-green algae dominating in some cases. For macrophytic plants, dense stands of Sphagnum and Utricularia are found in some acidic lakes which may reduce nutrient availability and benthic regeneration. Hydrogen ion concentration does not appear to be as important as inorganic phosphorus in controlling primary production and biomass in acidic lakes. In acidic, oligotrophic lakes, benthic plants may have a competitive advantage over pelagic algae because of the high concentrations of inorganic carbon and phosphorus available to them in the sediment.

  15. Prebiotic Metabolisms: Photo catalysis of the rTCA cycle by sphalerite colloids

    NASA Astrophysics Data System (ADS)

    Mangiante, D. M.; Bowen, B.; Northen, T.; Banfield, J. F.

    2010-12-01

    Explorations of mineral catalyzed reverse tricarboxylic acid (rTCA) cycle reactions provide a window into possible mechanisms for prebiotic metabolisms and the origins of life. The excitation of nano-scale semiconducting sphalerite minerals by ultra-violate light results in reducing electrons capable of catalyzing the reduction reactions present in the rTCA cycle. Current literature has utilized ion chromatography methods to characterize catalysis of two of the five redox active rTCA cycle compounds with high yield. This technique is unable to produce the untargeted analysis required to anticipate the myriad side reactions driven by excited photoelectrons and their ensuing radicals. By employing liquid chromatography coupled to mass spectrometry (LC-MS) we can examine the complete range of metabolites present across a reaction time series. The three dimensional LC-MS data set allows for the qualitative determination of individual metabolite features, while the comparison of intensities yields quantitative rates. These results allow us to describe the complete set of reactions resultant from a single rTCA cycle organic acid on a photo-activated sphalerite surface and provide a possible mechanism for how metabolic pathways could operate in enzyme free environments.

  16. [Concentrations and acidity contributions of acetate and formate in precipitation at 14 stations of China].

    PubMed

    He, Xiao-huan; Xu, Xiao-bin; Yu, Xiao-lan; Tang, Jie

    2010-04-01

    To investigate the concentrations of organic acids in precipitation in China and their contributions to the total acidity of precipitation, samples were taken at 14 stations of regional representativeness in 2007 and analyzed for acetate and formate using ion chromatography. In this paper, data of acetate and formate in precipitation at 14 stations are presented, wet depositions of these organic acids are calculated, and contributions of them to the total free acidity (TFA) of precipitation are estimated. Based on the measurements, the mean concentrations of formate at different stations were in the range of 0.96-3.43 micromol/L, and those of acetate in the range of 0-5.13 micromol/L, close to the levels at remote sites in other countries and at the lower ends of concentration ranges from previous measurements in China. Comparisons indicate that the concentrations of the organic acids at remote sites are lower than those at sites in the vicinity of urban areas. The annual wet depositions of formate and acetate were estimated to be in the ranges of 0.38-4.18 mmol/(m2 x a) and 0.06-5.87 mmol/(m2 x a), respectively, with larger depositions in southern China and smaller depositions in northern China. The relative contributions of the two organic acids to the TFA of precipitation were estimated to be in the range of 0.02%-51.6%, with an overall average of 2.95%. This suggests that although acid rain in China is mainly caused by emissions of sulfur and nitrogen oxides, organic acids can significantly contribute to the acidification of precipitation in some regions and during some periods, hence need to be included in observational studies of acid rain.

  17. Considerations of an air-quality standard to protect terrestrial vegetation from acidic precipitation

    SciTech Connect

    Evans, L.S.

    1981-01-01

    Studies on the effects of acidic precipitation which is here defined as wet or frozen deposition with a hydrogen ion concentration greater than 2.5 ..mu..eq 1/sup -1/, are reviewed. At the present time there is an inadequate amount of information that shows decreases in crop growth except for one field study. Most studies with plants (crops and forests) are inadequate for standard setting because they are not conducted in the field with adequate randomization of plots coupled with rigorous statistical analyses. Although visible injury to foliage has been documented in a variety of greenhouse studies, no experimental evidence demonstrates loss of field crop value or reduction in plant productivity due to visible foliar injury. Acidic precipitation can contribute nutrients to vegetation and could also influence leaching rates of nutrients from vegetation. Although these processes occur, there are no data that show changes in nutrient levels in foliage that relate to crop or natural ecosystem productivity. Experimental results show that fertilization of ferns is inhibited by current levels of acidic precipitation in the northeastern United States. However, the overall impacts of inhibited fertilization on perpetuation of the species or ecosystem productivity have not been evaluated. Simulated acidic precipitation has been shown to effect plant pathogens in greenhouse and field experiments. Simulated acidic precipitation inhibited pathogen activities under some circumstances and promoted pathogen activities under other circumstances. No conclusion can be drawn about the effects of current levels of precipitation acidity on plant pathogen-host interactions. From these data it must be concluded that research on the effects of acidic precipitation on terrestrial vegetation is too meager to draw any conclusions with regard to an air quality standard.

  18. Acid Precipitation Learning Materials: Science, Environmental and Social Studies, Grades 6-12.

    ERIC Educational Resources Information Center

    Hessler, Edward W.

    The major environmental problem of acid precipition is addressed through a series of activities contained in this guide for teachers of grades 6 through 12. Exercises are provided to help students learn science inquiry skills, facts, and concepts while focusing on the acid rain situation. Activities are organized by content areas. These include:…

  19. Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid

    SciTech Connect

    Dabbs, Daniel M.; Ramachandran, Usha; Lu, Sang; Liu, Jun; Wang, Li Q.; Aksay, Ilhan A.

    2005-12-06

    Citric acid has been shown to act as an agent for increasing the solubility of aluminum oxyhydroxides in aqueous solutions of high (>2.47 mol/mol) hydroxide-to-aluminum ratios. Conversely, citric acid also colloidally stabilizes particles in aqueous suspensions of aluminum-containing particles. Solutions of aluminum chloride, with and without citric acid added, were titrated with NaO(aq). The presence and size of particles were determined using quasi-elastic light scattering. In solutions that contained no citric acid, particles formed instantaneously when NaOH(aq) was added but these were observed to rapidly diminish in size, disappearing at OH/Al ratios below 2.5 mol/mol. When the OH/Al ratio was raised beyond 2.5 by addingmoreNaOH(aq), suspensions of colloidally stable particles formed. Large polycations containing 13 aluminum atoms were detected by 27Al solution NMR in citric-acid-free solutions with OH/Al ratios slightly lower than 2.5. In comparison, adding citric acid to solutions of aluminum chloride inhibited the formation of large aluminum-containing polycations. The absence of the polycations prevents or retards the subsequent formation of particles, indicating that the polycations, when present, act as seeds to the formation of new particles. Particles did not form in solutions with a citric acid/aluminum ratio of 0.8 until sufficient NaOH(aq) was added to raise the OH/Al ratio to 3.29. By comparison, lower amounts of citric acid did not prevent particles from forming but did retard the rate of growth.

  20. Effects of acid precipitation on cation transport in New Hampshire forest soils. Technical completion report

    SciTech Connect

    Cronan, C.S.

    1981-07-01

    This report describes the results of our investigation of the effects of regional acid precipitation on forest soils and watershed biogeochemistry in New England. The report provides descriptions of the following research findings: (1) acid precipitation may cause increased aluminum mobilization and leaching from soils to sensitive aquatic systems; (2) acid deposition may shift the historic carbonic acid/organic acid leaching regime in forest soils to one dominated by atmospheric H/sub 2/SO/sub 4/; (3) acid precipitation may accelerate nutrient cation leaching from forest soils and may pose a particular threat to the potassium resources of northeastern forested ecosystems; (4) while acid rain may pass through some coniferous canopies without being neutralized, similar inputs of acid rainfall to hardwood canopies may be neutralized significantly by Bronsted base leaching and by leaf surface ion exchange mechanisms; and (5) progressive acid dissolution of soils in the laboratory may provide an important tool for predicting the patterns of aluminum leaching from soils exposed to acid deposition.

  1. [Study on solid dispersion of precipitated calcium carbonate-based oleanolic acid].

    PubMed

    Yan, Hong-mei; Zhang, Zhen-hai; Jia, Xiao-bin; Jiang, Yan-rong; Sun, E

    2015-05-01

    Oleanolic acid-precipitated calcium carbonate solid dispersion was prepared by using solvent evaporation method. The microscopic structure and physicochemical properties of solid dispersion were analyzed using differential scanning calorimetry and scanning electron microscopy (SEM). And its in vitro release also was investigated. The properties of the precipitated calcium carbonate was studied which was as a carrier of oleanolic acid solid dispersion. Differential scanning calorimetry analysis suggested that oleanolic acid may be present in solid dispersion as amorphous substance. The in vitro release determination results of oleanolic acid-precipitated calcium carbonate (1: 5) solid dispersion showed accumulated dissolution rate of.oleanolic acid was up to 90% at 45 min. Accelerating experiment showed that content and in vitro dissolution of oleanolic acid solid dispersion did not change after storing over 6 months. The results indicated that in vitro dissolution of oleanolic acid was improved greatly by the solid dispersion with precipitated calcium carbonate as a carrier. The solid dispersion is a stabilizing system which has actual applied value.

  2. Reconciling Empirical Carbonate Clumped Isotope Calibrations: A Comparison of Calcite Precipitation and Acid Digestion Methods

    NASA Astrophysics Data System (ADS)

    Kelson, J.; Huntington, K. W.; Schauer, A. J.; Saenger, C.; Lechler, A. R.

    2015-12-01

    An accurate empirical calibration is necessary to confidently apply the carbonate clumped isotope (Δ47) thermometer. Previous synthetic carbonate calibrations disagree in temperature sensitivity, with one group of calibrations displaying a shallow Δ47-temperature slope (e.g., Dennis & Schrag, GCA, 2010), and the other a steep slope (e.g., Zaarur et al., EPSL, 2013). These calibrations differ in both the method of mineral precipitation and the temperature of the phosphoric acid used to digest carbonates for analysis, making it difficult to isolate the cause of the discrepancy. Here, we precipitate synthetic carbonates at temperatures of 6-80ºC using 4 different precipitation methods, and analyze the samples using both 90 and 25°C acid digestion. Precipitation experiments varied the use of salts (NaHCO3 and CaCl2) vs. dissolved CaCO3 as a starting solution, the use of carbonic anhydrase to promote isotopic equilibrium among dissolved inorganic carbon species in solution, and the method by which CO2 degasses to force carbonate precipitation. Carbonates precipitated by using salts and allowing CO2 to passively degas produce a shallow calibration slope that we hypothesize to approach isotopic equilibrium. Precipitation methods that bubble CO2 into solution then degas that CO2 (either passively or actively by bubbling N2) produce carbonates with consistently lower Δ47 and higher δ18O values for a given growth temperature. We infer that these carbonates grew in disequilibrium during rapid CO2 degassing. Varying acid digestion temperature does not change the results; acid fractionation factor is not correlated with grain size, Δ47, or d47 values. No precipitation method produces a steep calibration slope. Our large sample set of >60 carbonates lend confidence to a shallow slope calibration, and inform interpretations of Δ47 and δ18O values of natural carbonates that grow under conditions of isotopic disequilibrium.

  3. The TCA Pathway is an Important Player in the Regulatory Network Governing Vibrio alginolyticus Adhesion Under Adversity

    PubMed Central

    Huang, Lixing; Huang, Li; Yan, Qingpi; Qin, Yingxue; Ma, Ying; Lin, Mao; Xu, Xiaojin; Zheng, Jiang

    2016-01-01

    Adhesion is a critical step in the initial stage of Vibrio alginolyticus infection; therefore, it is important to understand the underlying mechanisms governing the adhesion of V. alginolyticus and determine if environmental factors have any effect. A greater understanding of this process may assist in developing preventive measures for reducing infection. In our previous research, we presented the first RNA-seq data from V. alginolyticus cultured under stress conditions that resulted in reduced adhesion. Based on the RNA-seq data, we found that the Tricarboxylic acid cycle (TCA pathway) might be closely related to adhesion. Environmental interactions with the TCA pathway might alter adhesion. To validate this, bioinformatics analysis, quantitative Real-Time PCR (qPCR), RNAi, and in vitro adhesion assays were performed, while V. alginolyticus was treated with various stresses including temperature, pH, salinity, and starvation. The expression of genes involved in the TCA pathway was confirmed by qPCR, which reinforced the reliability of the sequencing data. Silencing of these genes was capable of reducing the adhesion ability of V. alginolyticus. Adhesion of V. alginolyticus is influenced substantially by environmental factors and the TCA pathway is sensitive to some environmental stresses, especially changes in pH and starvation. Our results indicated that (1) the TCA pathway plays a key role in V. alginolyticus adhesion: (2) the TCA pathway is sensitive to environmental stresses. PMID:26870007

  4. National Acid Precipitation Assessment Program: 1990 Integrated Assessment report

    SciTech Connect

    Not Available

    1991-11-01

    The document, the 'Integrated Assessment,' is a summary of the causes and effects of acidic deposition and a comparison of the costs and effectiveness of alternative emission control scenarios. In developing the 'Integrated Assessment,' it was NAPAP's goal to produce a structured compilation of policy-relevant technical information. The Integrated Assessment is based on findings and data from a series of twenty-seven State-of-Science/Technology Reports (SOS/T) on acidic deposition published by NAPAP in 1990. The scope of the documents includes: (1) emissions, atmospheric processes and deposition; (2) effects on surface waters, forests, agricultural crops, exposed materials, human health, and visibility; and (3) control technologies, future emissions, and effects valuation.

  5. The effects of acid precipitation runoff on source water quality

    SciTech Connect

    Leibfried, R.T.; DeWalle, D.R.; Sharpe, W.A.

    1984-03-01

    The quality of water in two small streams that provide supplies to the water systems of Jennerstown and Boalsburg, Pa., was monitored during episodes of acid runoff in February 1981 (Card Machine Run) and March 1983 (Galbraith Gap Run): Changes in pH, in the concentration of aluminum, and in the Ryznar Stability Index were determined. The magnitude and potential importance of these changes are discussed.

  6. Effects of acid precipitation runoff on source water quality

    SciTech Connect

    Leibfried, R.T.; Sharpe, W.E.; DeWalle, D.R.

    1984-03-01

    The quality of water in two small streams that provide supplies to the water systems of Jennerstown and Boalsburg, Pa., was monitored during episodes of acid runoff in February 1981 (Card Machine Run) and March 1983 (Galbraith Gap Run). Changes in pH, in the concentration of aluminum, and in the Ryznar Stability Index were determined. The magnitude and potential importance of these changes are discussed. 17 references, 2 figures.

  7. A numerical simulation of the distribution of acid precipitation in Chongqing area of China

    NASA Astrophysics Data System (ADS)

    Lei, Xiao'en; Jia, Xinyuan; Yuan, Suzhen; Luo, Qiren; Chen, Silong; Xu, Yu

    1987-09-01

    A numerical model for the study of the regional acid precipitation is developed. The model consists of five parts: the distribution patterns of SO2 concentration, the mesoscale flow fields, the parameterization of SO2 transformation into SO{4/-}, the parameterization of precipitation scavenging process, and the relationship between SO2 content in precipitation and ground level concentration of SO2 in the air. The distribution of SO2, SO{2/-} and pH for all precipitations in Chongqing area during the period of July to October 1982 are simulated with the model. A comparison of the simulated results with experimental data shows that high SO2 concentration centres correspond to low pH centres. The source of the acid rain in Chongqing area is local air pollution which is due to the lower effective stack height, low wind velocity in the area, basin topography, and the use of coal with high sulphur content. The mechanism for the formation of the acid precipitation here may be different from that in the United States of America and the Western Europe, where acid rain appears in the area far from pollution source.

  8. Dissolution and precipitation reactions in human tooth enamel under weak acid conditions.

    PubMed

    Borggreven, J M; Driessens, F C; van Dijk, J W

    1986-01-01

    Slices of enamel were demineralized in weak acid solutions at pH 5. The solutions were analysed for Ca, P, Na and Mg. A substantial increase of the Ca/P ratio in the solution after about 6 h of demineralization was ascribed to brushite formation. The ratios of liberated Ca/Na, P/Na, Ca/Mg and P/Mg were always lower than the correspondent ratios in sound enamel. It was concluded that precipitation of brushite, and a preferential dissolution of Na and Mg compounds from the enamel both play a role in the dissolution-precipitation reactions in dental enamel during acid attack.

  9. Detecting acid precipitation impacts on lake water quality

    NASA Astrophysics Data System (ADS)

    Loftis, Jim C.; Taylor, Charles H.

    1989-09-01

    The United States Environmental Protection Agency is planning to expand its long-term monitoring of lakes that are sensitive to acid deposition effects. Effective use of resources will require a careful definition of the statistical objectives of monitoring, a network design which balances spatial and temporal coverage, and a sound approach to data analysis. This study examines the monitoring objective of detecting trends in water quality for individual lakes and small groups of lakes. Appropriate methods of trend analysis are suggested, and the power of trend detection under seasonal (quarterly) sampling is compared to that of annual sampling. The effects of both temporal and spatial correlation on trend detection ability are described.

  10. Effect of simulated acid precipitation on algal fixation of nitrogen and carbon dioxide in forest soils

    SciTech Connect

    Chang, F.H.; Alexander, M.

    1983-01-01

    Three forest soils from areas exposed to acid precipitation were incubated for 21 days in the light to enhance the development of indigenous algae. The rates of nitrogen fixation (acetylene reduction) in the light and dark were significantly less if the soils were treated with simulated rain at pH 3.5 than at pH 5.6. The inhibition increased with increasing amounts of simulated rain at pH 3.5. The fixation of CO/sub 2/ in the light was significantly less in the three soils following their exposure to simulated precipitation at pH 3.5 than to the same solutions at pH 5.6, and the extent of suppression rose with increasing amounts of synthetic rain. It is suggested that algae in terrestrial ecosystems may be especially susceptible to acid precipitation.

  11. IMPROVEMENT UPON THE CARRIER PRECIPITATION OF PLUTONIUM IONS FROM NITRIC ACID SOLUTIONS

    DOEpatents

    James, R.A.; Thompson, S.G.

    1958-12-23

    A process is reported for improving the removal of plutonlum by carrier precipitation by the addition of nitrite ions to a nitrlc acid solutlon of neutronirradiated unanium so as to destroy any hydrazine that may be present in the solution since the hydrazine tends to complex the tetravalent plutonium and prevents removal by the carrier precipltate, such as bismuth phospbate.

  12. [Low-molecular-weight organic acids in precipitation in Zunyi City, Guizhou province].

    PubMed

    Jiang, Wei; Lee, Xin-qing; Zeng, Yong; Huang, Rong-sheng; Tan, Ling; Xu, Gang; Wang, Bing

    2008-09-01

    Formic (HCOOH) and acetic (CH3COOH) acids are ubiquitous in troposphere. Studies on the low-molecular carboxylic acids help shed light on the biogeochemical cycles of carbon, hydrogen and oxygen, as well as on the formation of acid precipitation. As a city with severe acid precipitation, the city Zunyi in north Guizhou province, provide a typical background for gaining insight into the organic geochemistry in the heavily polluted atmospheric environment. We collected the precipitation in the downtown city for a whole year on the event basis, and measured inorganic and organic anions with ion chromatograph and cations with atomic absorption spectroscopy. The data demonstrate an annual average pH of 4.11, a clear indication of the acid atmosphere. The volume-weighted mean concentrations of [HCOO-]T and [CH3COO-]T were 9.29 micromol x L(-1) (ranged from 0.15 micromol x L(-1) to 46.14 micromol x L(-1)) and 6.47 micromol x L(-1) (ranged from 0.02 micromol x L(-1) to 19.11 micromol x L(-1)) respectively, accounting for 4.10% of the total anions. With a coefficient of 0.86, formic is significantly correlated with acetic acid, suggesting that both acids share common sources. The acids often decrease with time in a precipitation event, with occasional increases in the middle and last stages, indicating that the organic acids are primarily scavenged from blow cloud, with limited amount from the long distance transportation. The close range provenance of organic acids is facilitated by the local environmental condition, which is characterized by the mountain-enclosed valley with high humidity, low wind speed, and high atmospheric dust content. Based on the Henry's Law, we proposed the ratio of formic and acetic acids in the precipitation (F/A)aq as the indicator of the sources, and thus found that the anthropogenic sources are responsible for the organic compounds in the Spring and Winter, while vegetation emissions claim the sources in the Summer and Autumn.

  13. Metal chelate affinity precipitation: purification of BSA using poly(N-vinylcaprolactam-co-methacrylic acid) copolymers.

    PubMed

    Ling, Yuan-Qing; Nie, Hua-Li; Brandford-White, Christopher; Williams, Gareth R; Zhu, Li-Min

    2012-06-01

    This investigation involves the metal chelate affinity precipitation of bovine serum albumin (BSA) using a copper ion loaded thermo-sensitive copolymer. The copolymer of N-vinylcaprolactam with methacrylic acid PNVCL-co-MAA was synthesized by free radical polymerization in aqueous solution, and Cu(II) ions were attached to provide affinity properties for BSA. A maximum loading of 48.1mg Cu(2+) per gram of polymer was attained. The influence of pH, temperature, BSA and NaCl concentrations on BSA precipitation and of pH, ethylenediaminetetraacetic acid (EDTA) and NaCl concentrations on elution were systematically probed. The optimum conditions for BSA precipitation occurred when pH, temperature and BSA concentration were 6.0, 10°C and 1.0 mg/ml, respectively and the most favorable elution conditions were at pH 4.0, with 0.2M NaCl and 0.06 M EDTA. The maximum amounts of BSA precipitation and elution were 37.5 and 33.7 mg BSA/g polymer, respectively. It proved possible to perform multiple precipitation/elution cycles with a minimal loss of polymer efficacy. The results show that PNVCL-co-MAA is a suitable matrix for the purification of target proteins from unfractionated materials.

  14. Prediction of aluminum, uranium, and co-contaminants precipitation and adsorption during titration of acidic sediments.

    PubMed

    Tang, Guoping; Luo, Wensui; Watson, David B; Brooks, Scott C; Gu, Baohua

    2013-06-01

    Batch and column recirculation titration tests were performed with contaminated acidic sediments. A generic geochemical model was developed combining precipitation, cation exchange, and surface complexation reactions to describe the observed pH and metal ion concentrations in experiments with or without the presence of CO2. Experimental results showed a slow pH increase due to strong buffering by Al hydrolysis and precipitation and CO2 uptake. The cation concentrations generally decreased at higher pH than those observed in previous tests without CO2. Using amorphous Al(OH)3 and basaluminite precipitation reactions and a cation exchange selectivity coefficient K(Na\\Al) of 0.3, the model approximately described the observed (1) pH titration curve, (2) Ca, Mg, and Mn concentration by cation exchange, and (3) U concentrations by surface complexation with Fe hydroxides at pH < 5 and with liebigite (Ca2UO2(CO3)3·10H2O) precipitation at pH > 5. The model indicated that the formation of aqueous carbonate complexes and competition with carbonate for surface sites could inhibit U and Ni adsorption and precipitation. Our results suggested that the uncertainty in basaluminite solubility is an important source of prediction uncertainty and ignoring labile solid phase Al underestimates the base requirement in titration of acidic sediments.

  15. Prediction of aluminum, uranium, and co-contaminants precipitation and adsorption during titration of acidic sediments.

    PubMed

    Tang, Guoping; Luo, Wensui; Watson, David B; Brooks, Scott C; Gu, Baohua

    2013-06-01

    Batch and column recirculation titration tests were performed with contaminated acidic sediments. A generic geochemical model was developed combining precipitation, cation exchange, and surface complexation reactions to describe the observed pH and metal ion concentrations in experiments with or without the presence of CO2. Experimental results showed a slow pH increase due to strong buffering by Al hydrolysis and precipitation and CO2 uptake. The cation concentrations generally decreased at higher pH than those observed in previous tests without CO2. Using amorphous Al(OH)3 and basaluminite precipitation reactions and a cation exchange selectivity coefficient K(Na\\Al) of 0.3, the model approximately described the observed (1) pH titration curve, (2) Ca, Mg, and Mn concentration by cation exchange, and (3) U concentrations by surface complexation with Fe hydroxides at pH < 5 and with liebigite (Ca2UO2(CO3)3·10H2O) precipitation at pH > 5. The model indicated that the formation of aqueous carbonate complexes and competition with carbonate for surface sites could inhibit U and Ni adsorption and precipitation. Our results suggested that the uncertainty in basaluminite solubility is an important source of prediction uncertainty and ignoring labile solid phase Al underestimates the base requirement in titration of acidic sediments. PMID:23641798

  16. A model of annual orographic precipitation and acid deposition and its application to Snowdonia

    NASA Astrophysics Data System (ADS)

    Dore, A. J.; Mousavi-Baygi, M.; Smith, R. I.; Hall, J.; Fowler, D.; Choularton, T. W.

    A model of orographic rainfall has been used to estimate annual precipitation and acid wet deposition at a 1 km resolution for the Snowdonia mountains in North Wales. Comparison with measurements and existing rainfall maps of the UK showed that this approach was successful in reproducing the high annual precipitation peaks of up to 4000 mm annually that occur in this area. At 13 out of the 17 measurement sites, the modelled annual precipitation differed from long-term annual average measurements by no more than 25%. The process model was compared with a procedure used to map wet deposition of pollutants across the United Kingdom at a 5 km resolution. Significant differences between the two deposition data sets were apparent. With the mapping procedure, maximum wet deposition was correlated to areas of high precipitation in the northeast of the domain. With the process model, however, maximum deposition was observed over the smaller hills in the southwest of the domain, the first orographic barrier reached by the air mass in south-westerly flow. High exceedances of critical loads for acidic deposition to soils were calculated using the mapping procedure and found to be due to the high annual precipitation in Snowdonia. The seeder-feeder model represents a useful tool, which could be used for estimating annual wet deposition of pollutants and exceedance of critical loads in hill areas at a much finer resolution than the national transport models and deposition mapping routines that are commonly employed in the United Kingdom.

  17. Assessment of acidity of lakes and precipitation in the Sierra Nevada

    SciTech Connect

    Melack, J.M.

    1983-06-01

    The east central Sierra Nevada received acid precipitation (pH 3.7 to 4.9) during the convective storms interspersed through the dry seasons of 1981 and 1982. In contrast, late autumn, winter and early spring snow (1981-1982) ranged in pH from 5.2 to 6.1 (mean 5.7) and had low ammonium, nitrate and sulfate concentrations. As of 1981 most of the alpine lakes of the Sierra Nevada remain very weakly buffered, bicarbonate lakes that receive a small loading of acid precipitation and a large annual input of snowmelt uncontaminated by strong acids. These lakes contain low concentrations of orthophosphate, nitrate and ammonium and are oligotrophic. The zooplankton communities fall into two major groups, those dominated by large-bodied species in the absence of fish, and those dominated by smaller species where fish are present. If the acidity of the precipitation increases the pH of the lakes will decrease rapidly with adverse biological impacts because the lakes and their basins have extremely low buffer capacity and the biota cannot tolerate acidic water. 65 references, 14 figures, 6 tables.

  18. Effects of acid precipitation on reproduction in alpine plant species. [Erythronium grandiflorum; Aquilegia caerulea

    SciTech Connect

    McKenna, M.A.; Hille-Salgueiro, M.; Musselman, R.C. Dept. of Agriculture, Fort Collins, CO )

    1990-01-01

    A series of experiments were designed to determine the impact of acid rain on plant reproductive processes, a critical component of a species life history. Research was carried out in herbaceous alpine communities at the USDA (United States Department of Agriculture) Forest Service Glacier Lakes Ecosystem Experiments Site in the Snowy Mts. of Wyoming. A range of species were surveyed to monitor the sensitivity of pollen to acidification during germination and growth, and all species demonstrated reduced in vitro pollen germination in acidified media. Field pollinations were carried out in Erythronium grandiflorum and Aquilegia caerulea to determine the reproductive success of plants exposed to simulated ambient precipitation (pH 5.6) or simulated acid precipitation (pH 3.6) prior to pollination. In Erythronium, no differences were observed in seed set and seed weight of fruits resulting from the two pollination treatments. In Aquilegia, fruits resulting from the acid spray treatment produced fewer seeds and lighter seeds.

  19. Acidic and alkaline precipitation in the Cilician Basin, north-eastern Mediterranean Sea.

    PubMed

    Ozsoy, T; Saydam, A C

    2000-05-15

    Samples from precipitation events collected at Erdemli during February 1996-June 1997 were analyzed to determine their particulate aluminium content, in addition to pH and conductivity measurements. Backward air mass trajectories corresponding to the rainy days were analyzed to determine potential source regions of acidic and alkaline constituents transported to the Cilician Basin. Approximately 28% of the rain samples were found to be acidic and the trajectories associated with half of the acid precipitation events were from the Mediterranean Basin and the Balkan Peninsula, while the other half were from the Anatolian mainland and local sources. Rain samples were found to be alkaline (58%), with their trajectories originating from North Africa and the Middle East. As a result of its CaCO3 content, mineral dust from these arid regions significantly increased the pH of rainwater.

  20. Acid deposition in Maryland: Implications of the results of the National Acid Precipitation Assessment Program

    SciTech Connect

    DeMuro, J.; Bowmann, M.; Ross, J.; Blundell, C.; Price, R.

    1991-07-01

    Acid deposition, commonly referred to as 'acid rain,' is a major global environmental concern. Acid deposition has reportedly resulted in damage to aquatic, terrestrial, and physical resources and has potentially adverse effects on human health. A component of the Maryland acid deposition program is the preparation of an annual report that summarizes yearly activities and costs of ongoing acid deposition research and monitoring programs.

  1. Temporal trends in the acidity of precipitation and surface waters of New York

    USGS Publications Warehouse

    Peters, Norman E.; Schroeder, Roy A.; Troutman, David E.

    1982-01-01

    Statistical analyses of precipitation data from a nine-station monitoring network indicate little change in pH from 1965-78 within New York State as a whole but suggest that pH of bulk precipitation has decreased in the western part of the State by approximately 0.2 pH units since 1965 and increased in the eastern part by a similar amount. This trend is equivalent to an annual change in hydrogen-ion concentration of 0.2 microequivalents per liter. An average annual increase in precipitation quantity of 2 to 3 percent since 1965 has resulted in an increased acid load in the western and central parts of the State. During 1965-78, sulfate concentration in precipitation decreased an average of 1-4 percent annually. In general, no trend in nitrate was detected. Calculated trends in hydrogen-ion concentration do not correlate with measured trends of sulfate and nitrate, which suggests variable neutralization of hydrogen ion, possibly by particles from dry deposition. Neutralization has produced an increase of about 0.3 pH units in nonurban areas and 0.7 pH units in urban areas. Statistical analyses of chemical data from several streams throughout New York suggest that sulfate concentrations decreased an average of 1 to 4 percent per year. This decrease is comparable to the sulfate decrease in precipitation during the same period. In most areas of the State, chemical contributions from urbanization and farming, as well as the neutralizing effect of carbonate soils, conceal whatever effects acid precipitation may have on pH of streams.

  2. Mitochondrial engineering of the TCA cycle for fumarate production.

    PubMed

    Chen, Xiulai; Dong, Xiaoxiang; Wang, Yuancai; Zhao, Zihao; Liu, Liming

    2015-09-01

    Microbial fumarate production from renewable feedstock is a promising and sustainable alternative to petroleum-based chemical synthesis. Here, mitochondrial engineering was used to construct the oxidative pathway for fumarate production starting from the TCA cycle intermediate α-ketoglutarate in Candida glabrata. Accordingly, α-ketoglutarate dehydrogenase complex (KGD), succinyl-CoA synthetase (SUCLG), and succinate dehydrogenase (SDH) were selected to be manipulated for strengthening the oxidative pathway, and the engineered strain T.G-K-S-S exhibited increased fumarate biosynthesis (1.81 g L(-1)). To further improve fumarate production, the oxidative route was optimized. First, three fusion proteins KGD2-SUCLG2, SUCLG2-SDH1 and KGD2-SDH1 were constructed, and KGD2-SUCLG2 led to improved fumarate production (4.24 g L(-1)). In addition, various strengths of KGD2-SUCLG2 and SDH1 expression cassettes were designed by combinations of promoter strengths and copy numbers, resulting in a large increase in fumarate production (from 4.24 g L(-1) to 8.24 g L(-1)). Then, through determining intracellular amino acids and its related gene expression levels, argininosuccinate lyase in the urea cycle was identified as the key factor for restricting higher fumarate production. Correspondingly, after overexpression of it, the fumarate production was further increased to 9.96 g L(-1). Next, two dicarboxylic acids transporters facilitated an improvement of fumarate production, and, as a result, the final strain T.G-KS(H)-S(M)-A-2S reached fumarate titer of 15.76 g L(-1). This strategy described here paves the way to the development of an efficient pathway for microbial production of fumarate.

  3. Mitochondrial engineering of the TCA cycle for fumarate production.

    PubMed

    Chen, Xiulai; Dong, Xiaoxiang; Wang, Yuancai; Zhao, Zihao; Liu, Liming

    2015-09-01

    Microbial fumarate production from renewable feedstock is a promising and sustainable alternative to petroleum-based chemical synthesis. Here, mitochondrial engineering was used to construct the oxidative pathway for fumarate production starting from the TCA cycle intermediate α-ketoglutarate in Candida glabrata. Accordingly, α-ketoglutarate dehydrogenase complex (KGD), succinyl-CoA synthetase (SUCLG), and succinate dehydrogenase (SDH) were selected to be manipulated for strengthening the oxidative pathway, and the engineered strain T.G-K-S-S exhibited increased fumarate biosynthesis (1.81 g L(-1)). To further improve fumarate production, the oxidative route was optimized. First, three fusion proteins KGD2-SUCLG2, SUCLG2-SDH1 and KGD2-SDH1 were constructed, and KGD2-SUCLG2 led to improved fumarate production (4.24 g L(-1)). In addition, various strengths of KGD2-SUCLG2 and SDH1 expression cassettes were designed by combinations of promoter strengths and copy numbers, resulting in a large increase in fumarate production (from 4.24 g L(-1) to 8.24 g L(-1)). Then, through determining intracellular amino acids and its related gene expression levels, argininosuccinate lyase in the urea cycle was identified as the key factor for restricting higher fumarate production. Correspondingly, after overexpression of it, the fumarate production was further increased to 9.96 g L(-1). Next, two dicarboxylic acids transporters facilitated an improvement of fumarate production, and, as a result, the final strain T.G-KS(H)-S(M)-A-2S reached fumarate titer of 15.76 g L(-1). This strategy described here paves the way to the development of an efficient pathway for microbial production of fumarate. PMID:25708514

  4. Biomediated Precipitation of Calcium Carbonate and Sulfur in a Faintly Acidic Hot Spring

    NASA Astrophysics Data System (ADS)

    Jiang, L.; Peng, X.; Qiao, H.

    2014-12-01

    A faintly acidic hot spring named "female Tower" (T=73.5 ℃, pH=6.64 ) is located in the Jifei Geothermal Field,Yunnan province, Southwest China. The precipitates in the hot spring are composed of large amounts of calcite and sulfur, as reveals by XRD analysis. Scanning electron microscopy (SEM) analysis show the microbial mats are formed of various coccoid, rod and filamentous microbes. Transmission electron microscopy (TEM) analysis show that intracellular sulfur granules are commonly associated with these microbes. Energy dispersive X-ray spectrometer (EDS) analysis shows that the surface of microbes are mainly composed of Ca, C, O and S. A culture-independent molecular phylogenetic analysis demonstrates the majority of bacteria in the spring are sulfur-oxidizing bacteria. In the spring water, H2S concentration was up to 60 ppm, while SO42- concentration was only about 10 ppm. We suggest that H2S might be utilized by sulfur-oxidizing bacteria in this hot spring water, leading to the formation of sulfur granules intracellularly and extracellularly. In the meantime, this reaction increases the pH in ambient environments, which fosters the precipitation of calcium carbonate precipitation in the microbial mats. This study suggests that the sulfur-oxidizing bacteria could play an important role in calcium carbonate precipitation in faintly acidic hot spring environments.

  5. Acid deposition: State of science and technology. Summary report of the U. S. National Acid Precipitation Assessment Program

    SciTech Connect

    Irving, P.M.; Smith, E.

    1991-09-01

    The twenty-seven State-of-Science and State-of-Technology (SOS/T) Reports, published in 1990 as the definitive scientific and technical synthesis of information obtained during the first decade of the U.S. national Acid Precipitation Assessment Program (NAPAP), are summarized in the document. In most cases, these summaries were the final chapter of the complete SOS/T Report.

  6. Precipitation-chemistry measurements from the California Acid Deposition Monitoring Program, 1985-1990

    USGS Publications Warehouse

    Blanchard, Charles L.; Tonnessen, Kathy A.

    1993-01-01

    The configuration of the California Acid Deposition Monitoring Program (CADMP) precipitation network is described and quality assurance results summarized. Comparison of CADMP and the National Acid Deposition Program/National Trends Network (NADP/NTN) data at four parallel sites indicated that mean depth-weighted differences were less than 3 μeq ℓ−1 for all ions, being statistically significant for ammonium, sulfate and hydrogen ion. These apparently small differences were 15–30% of the mean concentrations of ammonium, sulfate and hydrogen ion. Mean depth-weighted concentrations and mass deposition rates for the period 1985–1990 are summarized; the latter were highest either where concentrations or precipitation depths were relatively high.

  7. Morphologies, mechanical properties and thermal stability of poly(lactic acid) toughened by precipitated barium sulfate

    NASA Astrophysics Data System (ADS)

    Yang, Jinian; Wang, Chuang; Shao, Kaiyun; Ding, Guoxin; Tao, Yulun; Zhu, Jinbo

    2015-11-01

    Poly(lactic acid) (PLA)-based composites were prepared by blending PLA with precipitated barium sulfate (BaSO4) modified with stearic acid. The morphologies, mechanical properties and thermal stability of samples with increased mass fraction of BaSO4 were investigated. Results showed that PLA was toughened and reinforced simultaneously by incorporation of precipitated BaSO4 particles. The highest impact toughness and elongation at break were both achieved at 15% BaSO4, while the elastic modulus increased monotonically with increasing BaSO4 loading. Little effect of BaSO4 on the thermal behavior of PLA was observed in the present case. However, the thermal stability of PLA/BaSO4 composites at high temperature was enhanced.

  8. Acid precipitation. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations concerning the causes, and ecological and economic consequences of acid precipitation and deposition. Emissions of sulfur and nitrogen compounds, loading rates at specific study sites, the role of buffering materials on the acidification of lakes and streams, and the effects on aquatic life are considered. The effects on soil chemistry and vegetation are also discussed. (Contains 250 citations and includes a subject term index and title list.)

  9. Precipitation chemistry and occurrence of acid rain over Dhanbad, coal city of India.

    PubMed

    Singh, Abhay Kr; Mondal, G C; Kumar, Suresh; Singh, K K; Kamal, K P; Sinha, A

    2007-02-01

    The present study investigated the chemical composition of wet atmospheric precipitation over Dhanbad, coal city of India. The precipitation samples were collected on event basis for three years (July 2003 to October 2005) at Central Mining Research Institute. The precipitation samples were analyzed for pH, conductivity, major anions (F, Cl, NO(3), SO(4)) and cations (Ca, Mg, Na, K, NH(4)). The pH value varied from 4.01 to 6.92 (avg. 5.37) indicating acidic to alkaline nature of rainwater. The pH of the rainwater was found well above the reference pH (5.6), showing alkalinity during the non-monsoon and early phase of monsoon, but during the late phase of monsoon, pH tendency was towards acidity (<5.6 pH) indicating the non-availability of proper neutralizer for acidic ions. The observed acidic events at this site were 91, (n = 162) accounting 56% for the entire monitoring months. The (NO(3) + Cl)/SO(4) ratio in majority of samples was found below 1.0, indicating that the acidity is greatly influenced by SO(4). The calculated ratio of (Ca + NH(4))/(NO(3) + SO(4)) ranges between 0.42-5.13 (average 1.14), however in most of the samples, the ratio is greater than unity (>1.0) indicating that Ca and NH(4) play an important role in neutralization of acidic ions in rainwater. Ca and SO(4) dominate the bulk ionic deposition and these two ions along with NH(4) accounts 63% of the annual ionic deposition.

  10. Influence of phosphate and silica on U(VI) precipitation from acidic and neutralized wastewaters

    SciTech Connect

    Kanematsu, Masakazu; Perdrial, Nicolas; Um, Wooyong; Chorover, Jon; O'Day, Peggy A.

    2014-06-03

    Uranium speciation and physical-chemical characteristics were studied in solids precipitated from synthetic acidic to circumneutral wastewaters in the presence and absence of dissolved silica and phosphate to examine thermodynamic and kinetic controls on phase formation. Composition of synthetic wastewater was based on disposal sites 216-U-8 and 216-U-12 Cribs at the Hanford site (WA, USA). In the absence of dissolved silica or phosphate, crystalline or amorphous uranyl oxide hydrates, either compreignacite or meta-schoepite, precipitated at pH 5 or 7 after 30 d of reaction, in agreement with thermodynamic calculations. In the presence of 1 mM dissolved silica representative of groundwater concentrations, amorphous phases dominated by compreignacite precipitated rapidly at pH 5 or 7 as a metastable phase and formation of poorly-crystalline boltwoodite, the thermodynamically stable uranyl silicate phase, was slow. In the presence of phosphate (3 mM), meta-ankoleite initially precipitated as the primary phase at pH 3, 5, or 7 regardless of the presence of 1 mM dissolved silica. Analysis of precipitates by U LIII-edge EXAFS indicated that “autunite-type” sheets of meta-ankoleite transformed to “phosphuranylite-type” sheets after 30 d of reaction, probably due to Ca substitution in the structure. Low solubility of uranyl phosphate phases limits dissolved U(VI) concentrations but differences in particle size, crystallinity, and precipitate composition vary with pH and base cation concentration, which will influence the thermodynamic and kinetic stability of these phases.

  11. Potential health implications for acid precipitation, corrosion, and metals contamination of drinking water.

    PubMed

    Sharpe, W E; DeWalle, D R

    1985-11-01

    Potential health effects of drinking water quality changes caused by acid precipitation are presented. Several different types of water supply are discussed and their roles in modifying acid rain impacts on drinking water are explained. Sources of metals contamination in surface water supplies are enumerated. The authors present some results from their research into acid rain impacts on roof-catchment cisterns, small surface water supplies, and lead mobilization in acid soils. A good correlation was obtained between cistern water corrosivity as measured by the Ryznar Index (RI) values and standing tapwater copper concentrations. However, lead concentrations in tapwater did not correlate well with cistern water RI. A modified linear regression model that accounted for Ryznar Index change during storage in vinyl-lined cisterns was used to predict the Ryznar Index value at a copper concentration of 1000 micrograms/L. The predicted RI was greater than the RI of precipitation with a pH of 5.3, indicating that anthropogenically acidified precipitation may result in cistern tapwater copper concentrations in excess of the 1000 micrograms/L suggested drinking water limit. Good correlations between tapwater Ryznar Index and tapwater copper and lead concentrations were not obtained for the small surface water supply. Aluminum concentrations in reservoir water were similar to those in stream source water. Limited data were also presented that indicated lead was present in acid forest soil leachate and streams draining such soils in relatively small concentrations. Where appropriate, recommendations for future research are included with the discussions of research results.

  12. Potential health implications for acid precipitation, corrosion, and metals contamination of drinking water.

    PubMed

    Sharpe, W E; DeWalle, D R

    1985-11-01

    Potential health effects of drinking water quality changes caused by acid precipitation are presented. Several different types of water supply are discussed and their roles in modifying acid rain impacts on drinking water are explained. Sources of metals contamination in surface water supplies are enumerated. The authors present some results from their research into acid rain impacts on roof-catchment cisterns, small surface water supplies, and lead mobilization in acid soils. A good correlation was obtained between cistern water corrosivity as measured by the Ryznar Index (RI) values and standing tapwater copper concentrations. However, lead concentrations in tapwater did not correlate well with cistern water RI. A modified linear regression model that accounted for Ryznar Index change during storage in vinyl-lined cisterns was used to predict the Ryznar Index value at a copper concentration of 1000 micrograms/L. The predicted RI was greater than the RI of precipitation with a pH of 5.3, indicating that anthropogenically acidified precipitation may result in cistern tapwater copper concentrations in excess of the 1000 micrograms/L suggested drinking water limit. Good correlations between tapwater Ryznar Index and tapwater copper and lead concentrations were not obtained for the small surface water supply. Aluminum concentrations in reservoir water were similar to those in stream source water. Limited data were also presented that indicated lead was present in acid forest soil leachate and streams draining such soils in relatively small concentrations. Where appropriate, recommendations for future research are included with the discussions of research results. PMID:4076096

  13. Colloidal precipitates related to Acid Mine Drainage: bacterial diversity and micro fungi-heavy metal interactions

    NASA Astrophysics Data System (ADS)

    Lucchetti, G.; Carbone, C.; Consani, S.; Zotti, M.; Di Piazza, S.; Pozzolini, M.; Giovine, M.

    2015-12-01

    In Acid Mine Drainage (AMD) settings colloidal precipitates control the mobility of Potential Toxic Elements (PTEs). Mineral-contaminant relationships (i.e. adsorption, ion-exchange, desorption) are rarely pure abiotic processes. Microbes, mainly bacteria and microfungi, can catalyze several reactions modifying the element speciation, as well as the bioavailability of inorganic pollutants. Soil, sediments, and waters heavily polluted with PTEs through AMD processes are a potential reservoir of extremophile bacteria and fungi exploitable for biotechnological purposes. Two different AMD related colloids, an ochraceous precipitate (deposited in weakly acidic conditions, composed by nanocrystalline goethite) and a greenish-blue precipitate (deposited at near-neutral pH, composed by allophane + woodwardite) were sampled. The aims of this work were to a) characterize the mycobiota present in these colloidal minerals by evaluating the presence of alive fungal propagules and extracting bacteria DNA; b) verify the fungal strains tolerance, and bioaccumulation capability on greenish-blue and ZnSO4 enriched media; c) evaluate potential impact of bacteria in the system geochemistry. The preliminary results show an interesting and selected mycobiota able to survive under unfavourable environmental conditions. A significant number of fungal strains were isolated in pure culture. Among them, species belonging to Penicillium and Trichoderma genera were tested on both greenish-blue and ZnSO4 enriched media. The results show a significant tolerance and bioaccumulation capability to some PTEs. The same colloidal precipitates were processed to extract bacteria DNA by using a specific procedure developed for sediments. The results give a good yield of nucleic acids and a positive PCR amplification of 16S rDNA accomplished the first step for future metagenomic analyses.

  14. Cation ratios in Cladonia portentosa as indices of precipitation acidity in the British Isles.

    PubMed

    Hyvärinen, M; Crittenden, P D

    1996-03-01

    The relationship between rainfall chemistry and the concentrations of potassium, calcium and magnesium in the apices (top 5 mm) of the cushion-forming; lichen Cladonia portentosa (Dufour) Coem was investigated. Lichen samples, together with underlying topsoil, were collected from heathlands in close proximity to rain gauges in the UK Acid Deposition Monitoring Network, located in rural areas of the British Isles, which provide wet deposition data based on weekly bulk samples. The ratios K(+) : Mg(2+) and extracellular Mg(2+) : intracellular Mg(2+) in the lichen apices were strongly correlated with H(+) concentration in precipitation. It is suggested that shifts in these ratios occur owing to enhanced displacement of extracellular Mg(2+) by elevated H(+) concentration in acid rain. By contrast, there was no indication of any relationship between total acid deposition and lichen chemistry. The concentration of Mg(2+) in the lichen was weakly correlated with that in soil, whereas lichen Ca(2+) content was not correlated with either precipitation or soil chemistry. It is concluded that these ratios describing changes in lichen Mg(2+) content provide good biomarkers for wet-deposited acidity.

  15. Effect of atmospheric sulfur pollutants derived from acid precipitation on the benthic dynamics of lakes

    SciTech Connect

    Mitchell, M.J.

    1982-11-01

    Sulfuric acid is a major contributor to acid precipitation in the United States. The relationship of acid precipitation to the sulfur dynamics of three lakes in New York was studied. For South Lake, which has probably been acidified, the sulfur profile in the sediment corresponded to historical changes in anthropogenic sulfur inputs. In all three study lakes, the organic sulfur constituents, which generally have been ignored in limnological investigations, played a major role in sulfur dynamics. The transformations and fluxes of inorganic and organic sulfur differed among the lakes and reflected characteristic abiotic and biotic properties, including productivity parameters. The community structure and secondary production of the invertebrate benthos were ascertained and, for South Lake, were similar to other acidified lakes. The importance of benthic insects on sulfur dynamics was demonstrated. Further studies on sulfur in lakes will enhance the understanding of the role of these anthropogenic inputs on lake systems and permit a more accurate appraisal of the present and future impacts of acidic deposition on water quality. 10 references.

  16. Biomediated Precipitation of Calcium Carbonate in a Slightly Acidic Hot Spring

    NASA Astrophysics Data System (ADS)

    Jiang, L.

    2015-12-01

    A slightly acidic hot spring named "Female Tower" (T=73.5 °C, pH=6.64) is located in the Jifei Geothermal Field, Yunnan Province, Southwest China. The precipitates in the hot spring are composed of large amounts of calcite, aragonite, and sulfur. Scanning electron microscopy (SEM) analyses revealed that the microbial mats were formed of various coccoid, rod-shaped, and filamentous microbes. Transmission electron microscopy (TEM) showed that the intracellular sulfur granules were commonly associated with these microbes. A culture-independent molecular phylogenetic analysis demonstrated that the majority of the bacteria in the spring were sulfur-oxidizing bacteria. In the spring water, H2S concentration was up to 60 ppm, while SO42- concentration was only about 10 ppm. We speculated that H2S might be utilized by sulfur-oxidizing bacteria in this hot spring water, leading to the intracellular formation of sulfur granules. In the meantime, this reaction increased the pH in the micron-scale microdomains, which fostered the precipitation of calcium carbonate in the microbial mats. The results of this study indicated that the sulfur-oxidizing bacteria could play an important role in calcium carbonate precipitation in slightly acidic hot spring environments.

  17. Fractionation of atmospheric acid and base components within storm events by precipitation scavenging processes.

    PubMed

    Liljestrand, H M

    1992-01-01

    Concentrations of ions in storm rainwater in Texas have been monitored for each 0.254 mm increment of precipitation. The changes in concentrations have been analyzed to investigate the role of differential rates of scavenging of particulate matter of differing particle size, and especially the major acid and base components. The empirical trend at the onset of rainfall is a chemical fractionation of acids and bases with correspondingly wide pH variations. These results are confirmed by model calculations, which show a significant preferential scavenging of calcium relative to sulfate in the first 10 mm of rainfall, resulting in fractionation of bases and acids from their atmospheric concentrations. Previous studies, using Target Transformation Factor Analysis of ion concentrations in storm precipitation and regional ambient aerosol data, statistically determined the average source for acidic secondary species and alkaline particulate matter. Two types of crustal sources were identified as western and eastern soil dust. In this study, an alternate physical explanation for these two soil dust factors is offered. As a storm progresses, the elements in the local soil dust are fractionated as a result of their differential rates of precipitation scavenging, enriching species predominantly in the fine particle size and depleting elements predominantly in the coarse particle size. This fractionation process results in a single source having different elemental ratios at the beginning and at the end of a rain event. For Austin, Dallas, and Tyler, Texas, the soil dust previously identified as being from eastern sources could, instead, be a fractionated form of the western soil source.

  18. Electrostatic precipitation of condensed acid mist: Third quarterly technical progress report, March 1--May 31, 1989

    SciTech Connect

    Not Available

    1989-01-01

    Acid mists can sometimes constitute a significant portion of the total particulate emissions from power plants burning high-sulfur coals. A wet electrostatic precipitator (WESP) is the best control option for acid mist. The mist would blind a fabric filter and attack glass fiber fabrics. A wet ESP is required because the acid would quickly corrode the plates in a conventional dry ESP. The wet ESP also offers the advantages of no rapping reentrainment and no sensitivity to fly ash resistivity. The project is organized in two phases. Phase I, which is scheduled for September 1988 to September 1989, involves the WESP fabrication, laboratory and pilot combustor testing, and computer modeling. Phase II, which is scheduled for September 1989 to September 1990, involves the solicitation of a utility demonstration site, preliminary site measurements, and planning for the demonstration test program. Progress on Phase I work is addressed in this discussion. 5 refs., 4 figs.

  19. Analysis and Multipoint Design of the TCA Concept

    NASA Technical Reports Server (NTRS)

    Krist, Steven E.; Bauer, Steven X. S.; Buning, Pieter G.

    1999-01-01

    The goal in this effort is to analyze the baseline TCA concept at transonic and supersonic cruise, then apply the natural flow wing design concept to obtain multipoint performance improvements. Analyses are conducted with OVERFLOW, a Navier-Stokes code for overset grids, using PEGSUS to compute the interpolations between the overset grids.

  20. Comparison between electrocoagulation and chemical precipitation for metals removal from acidic soil leachate.

    PubMed

    Meunier, Nathalie; Drogui, Patrick; Montané, Camille; Hausler, Robert; Mercier, Guy; Blais, Jean-François

    2006-09-01

    This paper provides a quantitative comparison between electrocoagulation and chemical precipitation based on heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) removal from acidic soil leachate (ASL) at the laboratory pilot scale. Chemical precipitation was evaluated using either calcium hydroxide or sodium hydroxide, whereas electrocoagulation was evaluated via an electrolytic cell using mild steel electrodes. Chemical precipitation was as effective as electrocoagulation in removing metals from ASL having low contamination levels (30 mg Pbl(-1) and 18 mg Znl(-1)). For ASL enriched with different metals (each concentration of metals was initially adjusted to 100 mg l(-1)), the residual Cr, Cu, Pb and Zn concentrations at the end of the experiments were below the acceptable level recommended for discharge in sewage urban works (more than 99.8% of metal was removed) using either electrocoagulation or chemical precipitation. Cd was more effectively removed by electrochemical treatment, whereas Ni was easily removed by chemical treatment. The cost for energy, chemicals and disposal of metallic residue of electrocoagulation process ranged from USD 8.83 to 13.95 tds(-1), which was up to five times lower than that recorded using chemical precipitation. Highly effective electrocoagulation was observed as the ASL was specifically enriched with high concentration of Pb (250-2000 mg Pbl(-1)). More than 99.5% of Pb was removed regardless of the initial Pb concentration imposed in ASL and, in all cases, the residual Pb concentrations (0.0-1.44 mg l(-1)) were below the limiting value (2.0 mg l(-1)) for effluent discharge in sewage works.

  1. Recovery of molybdenum, nickel and cobalt by precipitation from the acidic leachate of a mineral sludge.

    PubMed

    Vemic, M; Bordas, F; Comte, S; Guibaud, G; Lens, P N L; van Hullebusch, E D

    2016-09-01

    The objective of this study was to investigate the recovery potential of molybdenum (Mo), nickel (Ni) and cobalt (Co) from synthetic and real acidic leachate of a mineral sludge from a metal recycling plant by sulfide precipitation. The operational parameters (metal sulfide (M/S) ratio 0.1-1, agitation speed 0-100 rpm, contact time 15-120 min and pH 1-5) were optimized in batch conditions on synthetic metal leachate (0.5 M HNO3, Mo = 101.6 mg L(-1), Ni = 70.8 mg L(-1), Co = 27.1 mg L(-1)) with a 0.1 M Na2S solution. Additionally, recovery of the target metals was theoretically simulated with a chemical equilibrium model (Visual MINTEQ 3.0). The optimized Na2S precipitation of metals from the synthetic leachate resulted in the potential selective recovery of Mo at pH 1 (98% by modeling, 95% experimental), after simultaneous precipitation of Ni and Co as sulfide at pH 4 (100% by modeling, 98% experimental). Metal precipitation from the real leachate (18 M H2SO4, Mo = 10,160 mg L(-1), Ni = 7,080 mg L(-1), Co = 2,710 mg L(-1)) was performed with 1 M Na2S, and resulted in a maximal Mo recovery at pH 2 (50%), while maximal recoveries of Ni and Co were observed at pH 4 (56% and 60%, respectively). Real leachate gave a lower metals recovery efficiency compared with synthetic leachate, which can be attributed to changes in the pH, nature of leachant, co-precipitation of Zn and competition for S(2-) ions. PMID:26824137

  2. Recovery of molybdenum, nickel and cobalt by precipitation from the acidic leachate of a mineral sludge.

    PubMed

    Vemic, M; Bordas, F; Comte, S; Guibaud, G; Lens, P N L; van Hullebusch, E D

    2016-09-01

    The objective of this study was to investigate the recovery potential of molybdenum (Mo), nickel (Ni) and cobalt (Co) from synthetic and real acidic leachate of a mineral sludge from a metal recycling plant by sulfide precipitation. The operational parameters (metal sulfide (M/S) ratio 0.1-1, agitation speed 0-100 rpm, contact time 15-120 min and pH 1-5) were optimized in batch conditions on synthetic metal leachate (0.5 M HNO3, Mo = 101.6 mg L(-1), Ni = 70.8 mg L(-1), Co = 27.1 mg L(-1)) with a 0.1 M Na2S solution. Additionally, recovery of the target metals was theoretically simulated with a chemical equilibrium model (Visual MINTEQ 3.0). The optimized Na2S precipitation of metals from the synthetic leachate resulted in the potential selective recovery of Mo at pH 1 (98% by modeling, 95% experimental), after simultaneous precipitation of Ni and Co as sulfide at pH 4 (100% by modeling, 98% experimental). Metal precipitation from the real leachate (18 M H2SO4, Mo = 10,160 mg L(-1), Ni = 7,080 mg L(-1), Co = 2,710 mg L(-1)) was performed with 1 M Na2S, and resulted in a maximal Mo recovery at pH 2 (50%), while maximal recoveries of Ni and Co were observed at pH 4 (56% and 60%, respectively). Real leachate gave a lower metals recovery efficiency compared with synthetic leachate, which can be attributed to changes in the pH, nature of leachant, co-precipitation of Zn and competition for S(2-) ions.

  3. Mineral phases and mobility of trace metals in white aluminum precipitates found in acid mine drainage.

    PubMed

    Kim, Yeongkyoo

    2015-01-01

    The white aluminum precipitates (S1,S2,S4-1,S4-2) collected at three different locations affected by acid mine and rock drainage were studied to characterize the mineral phases and mobility of trace metals. Chemical analysis, XRD, SEM, NMR, and sequential extraction method were mainly used. XRD data showed that most white aluminum precipitates are amorphous with small amount of gypsum, which was also confirmed by SEM. The (27)Al MAS NMR spectra provide more detailed information on the local environments of aluminum in those samples. The samples collected at two locations (S3, and S4-1 and S4-2) contain 4-coordinated aluminum, suggesting that the samples contain a significant amount of amorphous phase from Al13-tridecamer. Chemical data of calcium and sulfur with (27)Al MAS NMR spectra suggest that the relative amounts of amorphous phase from Al13-tridecamer, hydrobasaluminite, aluminum hydroxide, and gypsum are different for each sample. Different amount of amorphous phase from Al13-tridecamer in those samples are probably caused by the different geochemical conditions and hydrolysis by aging in water. Sequential extraction results show that water soluble fraction and sorbed and exchangeable fraction of trace metals in sample collected as suspended particles (S1) are higher than other samples, and can affect the ecological system in waters by releasing aluminum and trace metals. These results suggest that careful characterization of white aluminum precipitates is needed to estimate the environmental effects of those precipitates in acid mine drainage. PMID:25213794

  4. Environmental risk assessment of airborne trichloroacetic acid--a contribution to the discussion on the significance of anthropogenic and natural sources.

    PubMed

    Ahlers, Jan; Regelmann, Jürgen; Riedhammer, Caroline

    2003-07-01

    In environmental risk assessments the question has to be answered, whether risk reduction measures are necessary in order to protect the environment. If the combination of natural and anthropogenic sources of a chemical substance leads to an unacceptable risk, the man-made emissions have to be reduced. In this case the proportions of the anthropogenic and natural emissions have to be quantified. Difficulties and possible solutions are discussed in the scope of the OECD- and EU-risk assessments of trichloroacetic acid (TCA) and tetrachloroethylene. In the atmosphere, TCA is formed by photo-oxidative degradation of tetrachloroethylene (PER) and 1,1,1-trichloroethane. The available data on atmospheric chemistry indicate that tetrachloroethylene is the more important pre-cursor. With its high water solubility and low volatility, TCA is adsorbed onto aerosol particles and precipitated during rainfalls. Extended monitoring in rainwater confirmed the global distribution of airborne TCA. TCA reaches soils by dry and wet deposition. In addition formation of TCA from tetrachloroethylene in plants was observed. Consequently, high concentrations were detected in needles, leaves and in forest soil especially in mountain regions. The effect assessment revealed that plants exposed via soil are the most sensitive species compared to other terrestrial organisms. A PNECsoil of 2.4 microg/kg dw was derived from a long-term study with pine and spruce seedlings. When this PNEC is compared with the measured concentrations of TCA in soil, in certain regions a PEC/PNEC ratio >1 is obtained. This clearly indicates a risk to the terrestrial ecosystem, with the consequence that risk reduction measures are deemed necessary. To quantify the causes of the high levels of TCA in certain soils, and to investigate the geographical extent of the problem, intensive and widespread monitoring of soil, air and rainwater for TCA and tetrachloroethylene would be necessary to be able to perform a full mass

  5. National Acid Precipitation Assessment Program annual report 1987 to the President and Congress

    SciTech Connect

    Not Available

    1988-04-01

    The document reports on 1987 research activities of the National Acid Precipitation Assessment Program (NAPAP). It outlines 1987 research highlights, future research activities, major deliverables, and the program's 1990 research objectives. Its seven substantive chapters cover NAPAP research in the areas of: Emissions and controls; Atmospheric chemistry; Atmospheric modeling and transport; Atmospheric deposition and air-quality monitoring; Terrestrial effects (on forests and crops); Aquatic effects; and Effects on materials and cultural resources. The document includes introductory materials on the National Program's organizational structure, efforts at research coordination, peer and program review activities, and budget. A complete listing of the program's 1987 publications is also included.

  6. Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

    NASA Technical Reports Server (NTRS)

    Muirhead, Dean

    2011-01-01

    Two batches of nominally pretreated and augmented urine were prepared with the baseline pretreatment formulation of sulfuric acid and chromium trioxide. The urine was augmented with inorganic salts and organic compounds in order to simulate a urinary ionic concentrations representing the upper 95 percentile on orbit. Three strong mineral acids: phosphoric, hydrochloric, and nitric acid, were substituted for the sulfuric acid for comparison to the baseline sulfuric acid pretreatment formulation. Three concentrations of oxidizer in the pretreatment formulation were also tested. Pretreated urine was distilled to 85% water recovery to determine the effect of each acid and its conjugate base on the precipitation of minerals during distillation. The brines were analyzed for calcium and sulfate ion, total, volatile, and fixed suspended solids. Test results verified that substitution of phosphoric, hydrochloric, or nitric acids for sulfuric acid would prevent the precipitation of gypsum up to 85% recovery from pretreated urine representing the upper 95 percentile calcium concentration on orbit.

  7. High-molecular-weight polymers for protein crystallization: poly-gamma-glutamic acid-based precipitants.

    PubMed

    Hu, Ting Chou; Korczyńska, Justyna; Smith, David K; Brzozowski, Andrzej Marek

    2008-09-01

    Protein crystallization has been revolutionized by the introduction of high-throughput technologies, which have led to a speeding up of the process while simultaneously reducing the amount of protein sample necessary. Nonetheless, the chemistry dimension of protein crystallization has remained relatively undeveloped. Most crystallization screens are based on the same set of precipitants. To address this shortcoming, the development of new protein precipitants based on poly-gamma-glutamic acid (PGA) polymers with different molecular-weight ranges is reported here: PGA-LM (low molecular weight) of approximately 400 kDa and PGA-HM (high molecular weight) of >1,000 kDa. It is also demonstrated that protein precipitants can be expanded further to polymers with much higher molecular weight than those that are currently in use. Furthermore, the modification of PGA-like polymers by covalent attachments of glucosamine substantially improved their solubility without affecting their crystallization properties. Some preliminary PGA-based screens are presented here.

  8. Boronic Acid functionalized core-shell polymer nanoparticles prepared by distillation precipitation polymerization for glycopeptide enrichment.

    PubMed

    Qu, Yanyan; Liu, Jianxi; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2012-07-16

    The boronic acid-functionalized core-shell polymer nanoparticles, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@4-vinylphenylboronic acid (poly(MBA-co-MAA)@VPBA), were successfully synthesized for enriching glycosylated peptides. Such nanoparticles were composed of a hydrophilic polymer core prepared by distillation precipitation polymerization (DPP) and a boronic acid-functionalized shell designed for capturing glycopeptides. Owing to the relatively large amount of residual vinyl groups introduced by DPP on the core surface, the VPBA monomer was coated with high efficiency, working as the shell. Moreover, the overall polymerization route, especially the use of DPP, made the synthesis of nanoparticles facile and time-saving. With the poly(MBA-co-MAA)@VPBA nanoparticles, 18 glycopeptides from horseradish peroxidase (HRP) digest were captured and identified by MALDI-TOF mass spectrometric analysis, relative to eight glycopeptides enriched by using commercially available meta-aminophenylboronic acid agarose under the same conditions. When the concentration of the HRP digest was decreased to as low as 5 nmol, glycopeptides could still be selectively isolated by the prepared nanoparticles. Our results demonstrated that the synthetic poly(MBA-co-MAA)@VPBA nanoparticles might be a promising selective enrichment material for glycoproteome analysis. PMID:22707097

  9. [Acidic components of precipitation: humid deposition of S, N and Cl compounds].

    PubMed

    Fernández Patier, R; Esteban Lefler, M

    1989-01-01

    Precipitation samples have been gathered using recipients that differentiate the dry deposition of the humidity in three stations in Spain: one urban (Madrid) and two at base levels (San Pablo de los Montes and Granada). The study is centred on the components of an acid character, for which significant special variations of the sulphate and nitrate concentrations have been obtained. The levels, highest in Madrid and lowest in San Pablo, show the influence of the emitting focal points. A study of the seasonal variations in San Pablo show that the concentrations in summer are more than double than those in winter, probably due to the intervention of the photochemical formation processes of these contaminants. Also studies of humidity deposition are carried out, from which one can observe greater monthly values that are greater in Madrid than in other stations, in spite of having less rainfall. Likewise, episodes of "acid rain" and "red rain" are commented on.

  10. Carbonate precipitation under bulk acidic conditions as a potential biosignature for searching life on Mars

    NASA Astrophysics Data System (ADS)

    Fernández-Remolar, David C.; Preston, Louisa J.; Sánchez-Román, Mónica; Izawa, Matthew R. M.; Huang, L.; Southam, Gordon; Banerjee, Neil R.; Osinski, Gordon R.; Flemming, Roberta; Gómez-Ortíz, David; Prieto Ballesteros, Olga; Rodríguez, Nuria; Amils, Ricardo; Darby Dyar, M.

    2012-10-01

    Recent observations of carbonate minerals in ancient Martian rocks have been interpreted as evidence for the former presence of circumneutral solutions optimal for carbonate precipitation. Sampling from surface and subsurface regions of the low-pH system of Río Tinto has shown, unexpectedly, that carbonates can form under diverse macroscopic physicochemical conditions ranging from very low to neutral pH (1.5-7.0). A multi-technique approach demonstrates that carbonate minerals are closely associated with microbial activity. Carbonates occur in the form of micron-size carbonate precipitates under bacterial biofilms, mineralization of subsurface colonies, and possible biogenic microstructures including globules, platelets and dumbbell morphologies. We propose that carbonate precipitation in the low-pH environment of Río Tinto is a process enabled by microbially-mediated neutralization driven by the reduction of ferric iron coupled to the oxidation of biomolecules in microbially-maintained circumneutral oases, where the local pH (at the scale of cells or cell colonies) can be much different than in the macroscopic environment. Acidic conditions were likely predominant in vast regions of Mars over the last four billion years of planetary evolution. Ancient Martian microbial life inhabiting low-pH environments could have precipitated carbonates similar to those observed at Río Tinto. Preservation of carbonates at Río Tinto over geologically significant timescales suggests that similarly-formed carbonate minerals could also be preserved on Mars. Such carbonates could soon be observed by the Mars Science Laboratory, and by future missions to the red planet.

  11. Microscopic evaluation of trace metals in cloud droplets in an acid precipitation region.

    PubMed

    Li, Weijun; Wang, Yan; Collett, Jeffrey L; Chen, Jianmin; Zhang, Xiaoye; Wang, Zifa; Wang, Wenxing

    2013-05-01

    Mass concentrations of soluble trace metals and size, number, and mixing properties of nanometal particles in clouds determine their toxicity to ecosystems. Cloud water was found to be acidic, with a pH of 3.52, at Mt. Lu (elevation 1,165 m) in an acid precipitation region in South China. A combination of Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Transmission Electron Microscopy (TEM) for the first time demonstrates that the soluble metal concentrations and solid metal particle number are surprisingly high in acid clouds at Mt. Lu, where daily concentrations of SO2, NO2, and PM10 are 18 μg m(-3), 7 μg m(-3), and 22 μg m(-3). The soluble metals in cloudwater with the highest concentrations were zinc (Zn, 200 μg L(-1)), iron (Fe, 88 μg L(-1)), and lead (Pb, 77 μg L(-1)). TEM reveals that 76% of cloud residues include metal particles that range from 50 nm to 1 μm diameter with a median diameter of 250 nm. Four major metal-associated particle types are Pb-rich (35%), fly ash (27%), Fe-rich (23%), and Zn-rich (15%). Elemental mapping shows that minor soluble metals are distributed within sulfates of cloud residues. Emissions of fine metal particles from large, nonferrous industries and coal-fired power plants with tall stacks were transported upward to this high elevation. Our results suggest that the abundant trace metals in clouds aggravate the impacts of acid clouds or associated precipitation on the ecosystem and human health.

  12. Evaluation of simulated acid precipitation effects on forest microcosms. Final report

    SciTech Connect

    Kelly, J.M.; Strickland, R.C.; Weatherford, F.P.; Noggle, J.C.

    1984-04-01

    Microcosms were treated for a 30-month period with simulated precipitation acidified to four pH levels (5.7, 4.5, 4.0, and 3.5) to evaluate the impact of acid precipitation on foliar leaching, plant nutrient content, soil leaching, soil nutrient content, and litter decomposition. Direct effects of acid precipitation on diameter growth, bud break, leaf senescence, chlorophyll content, stomatal size, stomatal density, photosynthesis, respiration, transpiration, and cuticle erosion were evaluated on tulip poplar, white oak, and Virginia pine seedlings growing as mixed stands in the microcosms. None of the plant physiological or morphological parameters evaluated responded in a statistically significant manner as a result of treatment. A significant treatment canopy interaction was observed in the form of a 60 percent increase in calcium input in throughfall in response to the pH 3.5 treatment. Foliar nutrient content did not change in response to treatment nor did field measurements of decomposer activity. Soil analysis indicated a significantly lower concentration of exchangeable calcium and magnesium in the top 3.5 cm of the mineral soil in association with the pH 3.5 treatment. Soil leachate concentrations exhibited significant increases at both the 25 and 50 cm depths. However, at the 100 cm depth no significant response in concentration or elemental loss from the system was observed. Laboratory respiration measurements indicated a small, but statistically significant reduction in decomposer activity in the lower litter (02) horizon. This reduction was masked in the field measurements of decomposer activity due to the relatively small contribution of the 02 to total soil respiration. 38 references, 12 figures, 18 tables.

  13. Effectiveness of coagulation and acid precipitation processes for the pre-treatment of diluted black liquor.

    PubMed

    Garg, Anurag; Mishra, I M; Chand, S

    2010-08-15

    The effectiveness of coagulation (using aluminium-based chemicals and ferrous sulfate) and acid precipitation (using H(2)SO(4)) processes for the pre-treatment of diluted black liquor obtained from a pulp and paper mill is reported. Commercial alum was found to be the most economical among all the aluminium and ferrous salts used as a coagulant. A maximum removal of chemical oxygen demand (COD) (ca. 63%) and colour reduction (ca. 90%) from the wastewater (COD = 7000 mg l(-1)) at pH 5.0 was obtained with alum. During the acid precipitation process, at pH < 5.0, significant COD reductions (up to 64%) were observed. Solid residue obtained from the alum treatment at a temperature of 95 degrees C showed much better (3 times) settling rate than that for the residue obtained after treatment with the same coagulant at a temperature of 25 degrees C. The settling curves had three parts, namely, hindered, transition and compression zones. Tory plots were used to determine the critical height of suspension-supernatant interface that is used in the design of a clarifier-thickener unit. High heating values and large biomass fraction of the solid residues can encourage the fuel users to use this waste derived sludge as a potential renewable energy source.

  14. The acid precipitation provisions of the 1990 Clean Air Act Amendments and minorities' energy consumption

    SciTech Connect

    Nieves, L.A.; Wernette, D.

    1991-01-01

    In November 1990 Congress passed a comprehensive set of amendments to the Clean Air Act of 1977 with potentially very high compliance costs. The provisions pertaining to control of acid precipitation have been specified with sufficient detail to examine their cost impacts. These provisions will require investment in emissions control technology, mainly by electric utilities. Production costs will increase due to the required investment, resulting in higher electricity prices. This paper examines the possible magnitude of these effects and whether there might be differential impacts on racial/ethnic minority groups. Differential impacts were considered a possibility because of the differences in the percentage of total income spent on energy by various population subgroups. In 1989, the Majority group (defined as non-Black, non-Hispanic) spent about three percent of household income on energy, while Blacks spent double that, six percent, and Hispanics spent about four percent. (The differences in income underlying these figures are greater, however, than the differences in energy expenditures). To address these issues, we compare projected electricity consumption and expenditures and total energy expenditures for Black, Hispanic, and Majority households. The distribution of benefits from reducing acid precipitation is not addressed since the possible effects on ambient air quality in specific geographical areas that are directly attributable to reducing utilities' sulfur dioxide emissions are highly uncertain.

  15. The acid precipitation provisions of the 1990 Clean Air Act Amendments and minorities` energy consumption

    SciTech Connect

    Nieves, L.A.; Wernette, D.

    1991-12-31

    In November 1990 Congress passed a comprehensive set of amendments to the Clean Air Act of 1977 with potentially very high compliance costs. The provisions pertaining to control of acid precipitation have been specified with sufficient detail to examine their cost impacts. These provisions will require investment in emissions control technology, mainly by electric utilities. Production costs will increase due to the required investment, resulting in higher electricity prices. This paper examines the possible magnitude of these effects and whether there might be differential impacts on racial/ethnic minority groups. Differential impacts were considered a possibility because of the differences in the percentage of total income spent on energy by various population subgroups. In 1989, the Majority group (defined as non-Black, non-Hispanic) spent about three percent of household income on energy, while Blacks spent double that, six percent, and Hispanics spent about four percent. (The differences in income underlying these figures are greater, however, than the differences in energy expenditures). To address these issues, we compare projected electricity consumption and expenditures and total energy expenditures for Black, Hispanic, and Majority households. The distribution of benefits from reducing acid precipitation is not addressed since the possible effects on ambient air quality in specific geographical areas that are directly attributable to reducing utilities` sulfur dioxide emissions are highly uncertain.

  16. Precipitation-Redispersion of Cerium Oxide Nanoparticles with Poly(acrylic acid): Toward Stable Dispersions

    SciTech Connect

    Sehgal,A.; Lalatonne, Y.; Berret, J.; Morvan, M.

    2005-01-01

    We exploit a precipitation-redispersion mechanism for complexation of short chain polyelectrolytes with cerium oxide nanoparticles to extend their stability ranges. As synthesized, cerium oxide sols at pH 1.4 consist of monodisperse cationic nanocrystalline particles having a hydrodynamic diameter of 10 nm and a molecular weight of 400 000 g mol{sup -1}. We show that short chain uncharged poly(acrylic acid) at low pH when added to a cerium oxide sols leads to macroscopic precipitation. As the pH is increased, the solution spontaneously redisperses into a clear solution of single particles with an anionic poly(acrylic acid) corona. The structure and dynamics of cerium oxide nanosols and their hybrid polymer-inorganic complexes in solution are investigated by static and dynamic light scattering, X-ray scattering, and chemical analysis. Quantitative analysis of the redispersed sol gives rise to an estimate of 40-50 polymer chains per particle for stable suspension. This amount represents 20% of the mass of the polymer-nanoparticle complexes. This complexation adds utility to the otherwise unstable cerium oxide dispersions by extending the range of stability of the sols in terms of pH, ionic strength, and concentration.

  17. Technical and economical assessment of formic acid to recycle phosphorus from pig slurry by a combined acidification-precipitation process.

    PubMed

    Daumer, M-L; Picard, S; Saint-Cast, P; Dabert, P

    2010-08-15

    Dissolution by acidification followed by a liquid/solid separation and precipitation of phosphorus from the liquid phase is one possibility to recycle phosphorus from livestock effluents. To avoid increase of effluent salinity by using mineral acids in the recycling process, the efficiency of two organic acids, formic and acetic acid, in dissolving the mineral phosphorus from piggery wastewater was compared. The amount of formic acid needed to dissolve the phosphorus was reduced three fold, compared to acetic acid. The amount of magnesium oxide needed for further precipitation was decreased by two with formic acid. Neither the carbon load nor the effluent salinity was significantly increased by using formic acid. An economical comparison was performed for the chemical recycling process (mineral fertilizer) vs. centrifugation (organic fertilizer) considering the centrifugation and the mineral fertilizers sold in the market. After optimisation of the process, the product could be economically competitive with mineral fertilizer as superphosphate in less than 10 years. PMID:20471746

  18. National Acid Precipitation Assessment Program Report to Congress: An Integrated Assessment

    SciTech Connect

    Uhart, M.; et al,

    2005-08-01

    Under Title IX of the 1990 Clean Air Act Amendments, Congress reauthorized the National Acid Precipitation Assessment Program (NAPAP) to continue coordinating acid rain research and monitoring, as it had done during the previous decade, and to provide Congress with periodic reports. In particular, Congress asked NAPAP to assess all available data and information to answer two questions: (1) What are the costs, benefits, and effectiveness of Title IV? This question addresses the costs and economic impacts of complying with the Acid Rain Program as well as benefit analyses associated with the various human health and welfare effects, including reduced visibility, damages to materials and cultural resources, and effects on ecosystems. (2) What reductions in deposition rates are needed to prevent adverse ecological effects? This complex questions addresses ecological systems and the deposition levels at which they experience harmful effects. The results of the assessment of the effects of Title IV and of the relationship between acid deposition rates and ecological effects were to be reported to Congress quadrennially, beginning with the 1996 report to Congress. The objective of this Report is to address the two main questions posed by Congress and fully communicate the results of the assessment to decision-makers. Given the primary audience, most of this report is not written as a technical document, although information supporting the conclusions is provided along with references.

  19. Performance of a pilot-scale wet electrostatic precipitator for the control of sulfuric acid mist.

    PubMed

    Huang, Jiayu; Wang, Hongmei; Shi, Yingjie; Zhang, Fan; Dang, Xiaoqing; Zhang, Hui; Shu, Yun; Deng, Shuang; Liu, Yu

    2016-10-01

    The use of a wet electrostatic precipitator (WESP) is often regarded as a viable option to reduce sulfuric acid mist emitted from the wet flue gas desulfurization (WFGD) tower in coal-fired power plants. In this study, a pilot-scale wet electrostatic precipitator equipped with a wall-cooled collection electrode is investigated for the control of sulfuric acid mist from a simulated WFGD system. The results show that due to partial charging effect, the removal efficiency of sulfuric acid aerosol decreases when the aerosol size decreases to several tens of nanometers. Moreover, due to the plasma-induced effect, a large number of ultrafine sulfuric acid aerosols below 50 nm formed at a voltage higher than 24 kV inside the WESP. The percentages of submicron-sized aerosols significantly increase together with the voltage. To minimize the adverse plasma-induced effect, a WESP should be operated at a high gas velocity with an optimum high voltage. Even at a high flue gas velocity of 2.3 m s(-1), the mass concentration and the total number concentration of uncaptured sulfuric acid aerosols at the WESP outlet are as low as ca. 0.6 mg m(-3) and ca. 10(4) 1 cm(-3) at 28 kV, respectively. The corresponding removal efficiencies were respectively higher than 99.4 and 99.9 % and are very similar to that at 1.1 and 1.6 m s(-1). Moreover, the condensation-induced aerosol growth enhances the removal of sulfuric acid mist inside a WESP and enables a low emission concentration of ca. 0.65 mg m(-3) with a corresponding removal efficiency superior to 99.4 % even at a low voltage of 21 kV, and of ca. 0.35 mg m(-3) with a corresponding removal efficiency superior to 99.6 % at a higher voltage level of 26 kV. PMID:27357706

  20. Performance of a pilot-scale wet electrostatic precipitator for the control of sulfuric acid mist.

    PubMed

    Huang, Jiayu; Wang, Hongmei; Shi, Yingjie; Zhang, Fan; Dang, Xiaoqing; Zhang, Hui; Shu, Yun; Deng, Shuang; Liu, Yu

    2016-10-01

    The use of a wet electrostatic precipitator (WESP) is often regarded as a viable option to reduce sulfuric acid mist emitted from the wet flue gas desulfurization (WFGD) tower in coal-fired power plants. In this study, a pilot-scale wet electrostatic precipitator equipped with a wall-cooled collection electrode is investigated for the control of sulfuric acid mist from a simulated WFGD system. The results show that due to partial charging effect, the removal efficiency of sulfuric acid aerosol decreases when the aerosol size decreases to several tens of nanometers. Moreover, due to the plasma-induced effect, a large number of ultrafine sulfuric acid aerosols below 50 nm formed at a voltage higher than 24 kV inside the WESP. The percentages of submicron-sized aerosols significantly increase together with the voltage. To minimize the adverse plasma-induced effect, a WESP should be operated at a high gas velocity with an optimum high voltage. Even at a high flue gas velocity of 2.3 m s(-1), the mass concentration and the total number concentration of uncaptured sulfuric acid aerosols at the WESP outlet are as low as ca. 0.6 mg m(-3) and ca. 10(4) 1 cm(-3) at 28 kV, respectively. The corresponding removal efficiencies were respectively higher than 99.4 and 99.9 % and are very similar to that at 1.1 and 1.6 m s(-1). Moreover, the condensation-induced aerosol growth enhances the removal of sulfuric acid mist inside a WESP and enables a low emission concentration of ca. 0.65 mg m(-3) with a corresponding removal efficiency superior to 99.4 % even at a low voltage of 21 kV, and of ca. 0.35 mg m(-3) with a corresponding removal efficiency superior to 99.6 % at a higher voltage level of 26 kV.

  1. Precipitation of Metallic Cations by the Acidic Exopolysaccharides from Bradyrhizobium japonicum and Bradyrhizobium (Chamaecytisus) Strain BGA-1

    PubMed Central

    Corzo, J.; León-Barrios, M.; Hernando-Rico, V.; Gutierrez-Navarro, A. M.

    1994-01-01

    The interaction between the acidic exopolysaccharides produced by two Bradyrhizobium strains and several metal cations has been studied. Aqueous solutions in the millimolar range of Fe3+ but not of Fe2+ precipitated the exopolysaccharides from Bradyrhizobium (Chamaecytisus) strain BGA-1 and, to a lesser extent, Bradyrhizobium japonicum USDA 110. The precipitation was pH dependent, with a maximum around pH 3. The precipitate was redissolved by changing the pH and by Fe3+ reduction or chelation. Deacetylation of B. japonicum polysaccharide increased its precipitation by Fe3+. At pH near neutrality, the polysaccharide from Bradyrhizobium (Chamaecytisus) strain BGA-1 stabilized Fe3+ solutions, despite the insolubility of Fe(OH)3. Aluminum precipitated Bradyrhizobium (Chamaecytisus) polysaccharide but not the polysaccharide produced by B. japonicum. The precipitation showed a maximum at about pH 4.8, and the precipitate was redissolved after Al3+ chelation with EDTA. Precipitation was inhibited by increases in the ionic strength over 10 mM. Bradyrhizobium (Chamaecytisus) polysaccharide was also precipitated by Th4+, Sn2+, Mn2+, and Co2+. The presence of Fe3+ increased the exopolysaccharide precipitation by aluminum. No precipitation, gelation, or increase in turbidity of polysaccharide solutions occurred when K+, Na+, Ca2+, Mg2+, Cu2+, Cd2+, Pb2+, Zn2+, Hg2+, or U6+ was added at several pH values. The results suggest that the precipitation is based on the interaction between carboxylate groups from different polysaccharide chains and the partially hydrolyzed aquoions of Fe3+, Al3+, Th4+, and Sn2+. PMID:16349466

  2. Nucleation kinetics of selenium (+4) precipitation from an acidic copper sulphate solution

    NASA Astrophysics Data System (ADS)

    Mangere, M.; Nathoo, J.; Lewis, A. E.

    2010-10-01

    The removal of selenium from copper sulphate solution prior to the electrowinning of copper is desirable in order to minimise contamination of the copper cathodes by selenium and other impurities. The selenium removal is effected by a precipitation process that takes place under high supersaturation conditions, which favour nucleation over any other particle formation processes. There is currently no fundamental information on the nucleation kinetics of this important process. In this study, the nucleation kinetics of selenium (+4) precipitation from an acidic copper sulphate solution was determined using the classical nucleation theory (CNT). Experiments were carried out by varying the levels of supersaturation from 8.66×10 15 to 4.33×10 17 at a temperature of 95 °C under atmospheric pressure. The nucleation rates for four different levels of supersaturation, the nucleation work and the nucleus size were determined. The kinetic constant A was found to be 3.92×10 27 m -3 s -1, which shows that the nucleation process takes place through a homogeneous mechanism. The associated thermodynamic parameter ( B) was determined to be 8.98×10 04.

  3. Determination of trifluoroacetic acid in 1996--1997 precipitation and surface waters in California and Nevada

    SciTech Connect

    Wujcik, C.E.; Cahill, T.M.; Seiber, J.N.

    1999-05-15

    The atmospheric degradation of three chlorofluorocarbon (CFC) replacement compounds, namely HFC-134a, HCFC-123, and HCFC-124, results in the formation of trifluoroacetic acid (TFA). Concentrations of TFA were determined in precipitation and surface water samples collected in California and Nevada during 1996--1997. Terminal lake systems were found to have concentrations 4--13 times higher than their calculated yearly inputs, providing evidence for accumulation. The results support dry deposition as the primary contributor of TFA to surface waters in arid and semiarid environments. Precipitation samples obtained from three different locations contained 20.7--1530 ng/L with significantly higher concentrations in fogwater over rainwater. Elevated levels of TFA were observed for rainwater collected in Nevada over those collected in California, indicating continual uptake and concentration as clouds move from a semiarid to arid climate. Thus several mechanisms exist, including evaporative concentration, vapor-liquid phase partitioning, lowered washout volumes of atmospheric deposition water, and dry deposition, which may lead to elevated concentrations of TFA in atmospheric and surface waters above levels expected from usual rainfall washout.

  4. Strong and Biostable Hyaluronic Acid-Calcium Phosphate Nanocomposite Hydrogel via in Situ Precipitation Process.

    PubMed

    Jeong, Seol-Ha; Koh, Young-Hag; Kim, Suk-Wha; Park, Ji-Ung; Kim, Hyoun-Ee; Song, Juha

    2016-03-14

    Hyaluronic acid (HAc) hydrogel exhibits excellent biocompatibility, but it has limited biomedical application due to its poor biomechanical properties as well as too-fast enzymatic degradation. In this study, we have developed an in situ precipitation process for the fabrication of a HAc-calcium phosphate nanocomposite hydrogel, after the formation of the glycidyl methacrylate-conjugated HAc (GMHA) hydrogels via photo-cross-linking, to improve the mechanical and biological properties under physiological conditions. In particular, our process facilitates the rapid incorporation of calcium phosphate (CaP) nanoparticles of uniform size and with minimal agglomeration into a polymer matrix, homogeneously. Compared with pure HAc, the nanocomposite hydrogels exhibit improved mechanical behavior. Specifically, the shear modulus is improved by a factor of 4. The biostability of the nanocomposite hydrogel was also significantly improved compared with that of pure HAc hydrogels under both in vitro and in vivo conditions. PMID:26878437

  5. Chemical composition and seasonal variation of acid deposition in Guangzhou, South China: comparison with precipitation in other major Chinese cities.

    PubMed

    Huang, De-Yin; Xu, Yi-Gang; Peng, Ping'an; Zhang, Hui-Huang; Lan, Jiang-Bo

    2009-01-01

    With the aim of understanding the origin of acid rains in South China, we analyzed rainwaters collected from Guangzhou, China, between March 2005 and February 2006. The pH of rainwater collected during the monitoring period varied from 4.22 to 5.87; acid rain represented about 94% of total precipitation during this period. The rainwater was characterized by high concentrations of SO(4)(2-), NO(3)(-), Ca(2+), and NH(4)(+). SO(4)(2-) and NO(3)(-), the main precursors of acid rain, were related to the combustion of coal and fertilizer use/traffic emissions, respectively. Ca(2+) and NH(4)(+) act as neutralizers of acid, accounting for the decoupling between high SO(4)(2-) concentrations and relatively high pH in the Guangzhou precipitation. The acid rain in Guangzhou is most pronounced during spring and summer. A comparison with acid precipitation in other Chinese cities reveals a decreasing neutralization capacity from north to south, probably related to the role and origin of alkaline bases in precipitation. PMID:18801606

  6. Chemical composition and seasonal variation of acid deposition in Guangzhou, South China: comparison with precipitation in other major Chinese cities.

    PubMed

    Huang, De-Yin; Xu, Yi-Gang; Peng, Ping'an; Zhang, Hui-Huang; Lan, Jiang-Bo

    2009-01-01

    With the aim of understanding the origin of acid rains in South China, we analyzed rainwaters collected from Guangzhou, China, between March 2005 and February 2006. The pH of rainwater collected during the monitoring period varied from 4.22 to 5.87; acid rain represented about 94% of total precipitation during this period. The rainwater was characterized by high concentrations of SO(4)(2-), NO(3)(-), Ca(2+), and NH(4)(+). SO(4)(2-) and NO(3)(-), the main precursors of acid rain, were related to the combustion of coal and fertilizer use/traffic emissions, respectively. Ca(2+) and NH(4)(+) act as neutralizers of acid, accounting for the decoupling between high SO(4)(2-) concentrations and relatively high pH in the Guangzhou precipitation. The acid rain in Guangzhou is most pronounced during spring and summer. A comparison with acid precipitation in other Chinese cities reveals a decreasing neutralization capacity from north to south, probably related to the role and origin of alkaline bases in precipitation.

  7. GC/TOFMS analysis of metabolites in serum and urine reveals metabolic perturbation of TCA cycle in db/db mice involved in diabetic nephropathy.

    PubMed

    Li, Mengjie; Wang, Xufang; Aa, Jiye; Qin, Weisong; Zha, Weibin; Ge, Yongchun; Liu, Linsheng; Zheng, Tian; Cao, Bei; Shi, Jian; Zhao, Chunyan; Wang, Xinwen; Yu, Xiaoyi; Wang, Guangji; Liu, Zhihong

    2013-06-01

    Early diagnosis of diabetic nephropathy (DN) is difficult although it is of crucial importance to prevent its development. To probe potential markers and the underlying mechanism of DN, an animal model of DN, the db/db mice, was used and serum and urine metabolites were profiled using gas chromatography/time-of-flight mass spectrometry. Metabolic patterns were evaluated based on serum and urine data. Principal component analysis of the data revealed an obvious metabonomic difference between db/db mice and controls, and db/db mice showed distinctly different metabolic patterns during the progression from diabetes to early, medium, and later DN. The identified metabolites discriminating between db/db mice and controls suggested that db/db mice have perturbations in the tricarboxylic acid cycle (TCA, citrate, malate, succinate, and aconitate), lipid metabolism, glycolysis, and amino acid turnover. The db/db mice were characterized by acidic urine, high TCA intermediates in serum at week 6 and a sharp decline thereafter, and gradual elevation of free fatty acids in the serum. The sharp drop of serum TCA intermediates from week 6 to 8 indicated the downregulated glycolysis and insulin resistance. However, urinary TCA intermediates did not decrease in parallel with those in the serum from week 6 to 10, and an increased portion of TCA intermediates in the serum was excreted into the urine at 8, 10, and 12 wk than at 6 wk, indicating kidney dysfunction occurred. The relative abundances of TCA intermediates in urine relative to those in serum were suggested as an index of renal damage.

  8. Comparison of haloacetic acids in the environment of the Northern and Southern Hemispheres.

    PubMed

    Scott, B F; Spencer, C; Martin, J W; Barra, R; Bootsma, H A; Jones, K C; Johnston, A E; Muir, D C G

    2005-11-15

    Haloacetic acids (HAAs) are a family of compounds whose environmental concentrations have been extensively studied, primarily in Europe. Depending on the compound, their sources are believed to be both natural and anthropogenic. To better understand possible sources and contribute to the knowledge of the global distribution of these compounds, especially between the Northern and Southern Hemispheres, samples of precipitation, soils, and conifer needles were collected from Canada, Malawi, Chile, and the U.K. Precipitation samples exhibited highest HAA concentrations in collections from Canada, and lowest in those from Malawi. Malawi samples contained measurable levels of monobromoacetic acid (MBA) (56 ng/ L) unlike those from most other locations (< 9 ng/L). Soil HAA concentration levels were highest in the U.K. (e.g., 7.3 ng/g average TCA) and lowest in Malawi (0.8 ng/g average TCA), with Chile having higher levels (4.8 ng/g average TCA) than Canada (3 ng/g average TCA). Malawi soils contained small amounts of MBA (2 ng/g), in common with the two most southern of the 11 Chilean sites. Analysis of soil cores (10-cm depth sliced at 1 cm) from sites in Malawi and Chile showed that trichloroacetic acid (TCA) generally declined with depth while mono- and dichloroacetic acid (MCA and DCA) showed no trend. MCA, DCA, and TCA concentrations in archived U.K. soil samples increased by factors of 2, 4, and 5-fold over 75 years while TFA showed no consistent trend. Monochloroacetic acid (MCA) was detected in pine needles collected from Malawi. U.K. needle samples had the highest concentrations of all chloroacetic acids (CAAs): MCA, 2-18 ng/g; dichloroacetic acid (DCA), 2-38 ng/g; and trichloroacetic acid (TCA), 28-190 ng/g. Conifer needles from Canada and Chile contained CAAs at levels ranging from < 2 to 16 ng/g wet wt. Trifluoroacetic acid concentrations generally declined with increasing elevation in the samples from the Rocky Mountains in western Canada. The results

  9. A study of the source-receptor relationships influencing the acidity of precipitation collected at a rural site in France

    NASA Astrophysics Data System (ADS)

    Charron, Aurélie; Plaisance, Hervé; Sauvage, Stéphane; Coddeville, Patrice; Galloo, Jean-Claude; Guillermo, René

    In order to examine the qualitative and quantitative source-receptor relationships responsible for acid rains at a background site in France, a receptor-oriented model was applied to the precipitation data collected from 1992 to 1995. Origins of acidic and alkaline species in precipitations have been investigated. The methodology combines precipitation chemical data with air parcel backward trajectories to establish concentration field maps of likely contributing sources. Highest acidities and concentrations of sulfate and nitrate in precipitation were associated with transport from the high emission areas of central Europe. Alkaline events were associated with air masses originating from Mediterranean basin or northern Africa. The quantitative relationships between the maps of potential sources and the European emissions of SO 2 and NO x were examined performing a correlation analysis. Good correlations were found between computed concentrations of acidic species and emissions of SO 2 and NO x. Substantial seasonal variations of acidic species were revealed. The highest concentrations occurred during the warm season. These seasonal variations are the effect of change of meteorological conditions and of the strength atmospheric processes according to the season.

  10. A simple procedure for preparing chitin oligomers through acetone precipitation after hydrolysis in concentrated hydrochloric acid.

    PubMed

    Kazami, Nao; Sakaguchi, Masayoshi; Mizutani, Daisuke; Masuda, Tatsuhiko; Wakita, Satoshi; Oyama, Fumitaka; Kawakita, Masao; Sugahara, Yasusato

    2015-11-01

    Chitin oligomers are of interest because of their numerous biologically relevant properties. To prepare chitin oligomers containing 4-6 GlcNAc units [(GlcNAc)4-6], α- and β-chitin were hydrolyzed with concentrated hydrochloric acid at 40 °C. The reactant was mixed with acetone to recover the acetone-insoluble material, and (GlcNAc)4-6 was efficiently recovered after subsequent water extraction. Composition analysis using gel permeation chromatography and MALDI-TOF mass spectrometry indicated that (GlcNAc)4-6 could be isolated from the acetone-insoluble material with recoveries of approximately 17% and 21% from the starting α-chitin and β-chitin, respectively. The acetone precipitation method is highly useful for recovering chitin oligomers from the acid hydrolysate of chitin. The changes in the molecular size and higher-order structure of chitin during the course of hydrolysis were also analyzed, and a model that explains the process of oligomer accumulation is proposed.

  11. Design and performance of an acidic precipitation delivery system for field investigations with plants.

    PubMed

    Lauver, T L; Laurence, J A; Kohut, R J

    1990-01-01

    An acidic precipitation delivery system is described that was designed and constructed for use in a field investigation of the response of red spruce saplings (Picea rubens Sarg.) to the interactive stresses of ozone and acid rain. The system utilizes hydraulic, solid-cone spray nozzles to produce simulated rainfall with droplet size distributions approximating natural rain events, which are of low intensity, i.e., about 1-1.5 cm hr(-1), and are relatively uniform in distribution of volume over a 2.4 m diameter plot. Three different pH treatments (3.1, 4.1, 5.1) were dispensed randomly to each of three treatment subplots located in twelve open-top field chambers and three ambient control chambers. Storage capacity of the system permitted a 2.3 hr rain event. Construction materials used were chosen for resistance to the corrosive nature of the rain simulant, stability to ambient UV radiation, and resistance to penetration by sunlight. Simulated events were not synchronized to ambient events, but were scheduled to prevent moisture deficits.

  12. Chemical characteristics and sources of organic acids in precipitation at a semi-urban site in Southwest China

    NASA Astrophysics Data System (ADS)

    Zhang, Y. L.; Lee, X. Q.; Cao, F.

    2011-01-01

    In order to investigate the chemical characteristics and sources of organic acids in precipitation in Southwest China, 105 rainwater samples were collected at a semi-urban site in Anshun from June 2007 to June 2008. Organic acids and major anions were analyzed along with pH and electrical conductivity. The pH values varied from 3.57 to 7.09 for all the rainfall events sampled, with an average of 4.67 which was typical acidic value. Formic, acetic and oxalic acids were found to be the predominant carboxylic acids and their volume weighted average (VWA) concentrations were 8.77, 6.93 and 2.84 μmol l -1, respectively. These organic acids were estimated to account for 8.1% to the total free acidity (TFA) in precipitation. The concentrations of the majority organic acids at studied site had a clear seasonal pattern, reaching higher levels during the non-growing season than those in growing season, which was attributed to dilution effect of heavy rainfall during the growing season. The seasonal variation of wet deposition flux of these organic acids confirmed higher source strength of biogenic emissions from vegetation during the growing season. Formic-to-acetic acids ratio (F/A), an indicator of primary versus secondary sources of these organic acids, suggested that primary sources from vehicular emission, biomass burning, soil and vegetation emissions were dominant sources. In addition, the lowest concentrations of organic acids were found under type S, when air masses originated from the marine (South China Sea) during Southern Asian Monsoon period. And the highest concentrations were observed in precipitation events from Northeast China (type NE), prevailing mostly during winter with the lowest rainfall.

  13. Integrated Lake-Watershed Acidification Study (ILWAS): contributions to the international conference on the ecological impact of acid precipitation

    SciTech Connect

    Not Available

    1981-05-01

    The Integrated Lake-Watershed Acidification Study (ILWAS) was initiated to study and detail lake acidification processes for three lake watershed basins in the Adirondack Park region of New York. The three basins (Woods, Sagamore, and Panther), receive similar amounts of acid deposition yet observable pH values for the lakes are very dissimilar indicating unequal acid neutralizing capacities among the watersheds. This volume contains a compilation of seven papers. Relevant topics include: a characterization of the geology, hydrology, limnology and vegetation of the three study sites, an analysis of acid precipitation quality and quantity, the effects of vegetative canopy, the effects of snowmelt, the effects of winter lake stratification, comparison of heavy metal transport, examination of acidic sources other than direct precipitation, assessment of lake acidification during spring thaw and integration of all acidification components with a mathematical model.

  14. A transport model of the dissolution of limestone and marble due to acid precipitation

    SciTech Connect

    Kishiyama, G.E.

    1991-01-01

    The dissolution rate of calcite is known to be a function of the hydrogen ion activity in a contacting solution. This is important in the case of accelerated weathering by acid precipitation, where the decrease in the natural pH of rainwater can cause significant damage. Experimental studies on inclined slabs of Salem Limestone and Shelburne Marble are being conducted both in the field and in the laboratory. This study is a theoretical model based on the laboratory experiments, and an attempt to relate the results to that obtained in the field studies. The laboratory experiments are modeled after failing film theory, where the flux of species into and out of the system at the solid-liquid interface are defined by the Plummer et al. reaction expressions. Electrochemical effects and chemical reactions in the bulk solution which contribute a buffering effect can alter the rate of mass transfer. A finite difference predictor-corrector method developed by Douglas was chosen to solve the coupled, non-linear equations describing this system. Hydrodynamics of rainfall onto a porous surface differ significantly from the well-known theory of laminar falling films. Hydrogen ion is quickly consumed after initial contact with the solid surface, resulting in large concentrations in the bulk fluid. The ensuing rate of mass transfer after consumption of acid closely resembles heat transfer into a semi-infinite slab with constant flux at the surface. Models for the distribution of raindrop sizes, descent velocity, and impact effect are developed based solely on rainfall intensity, which is provided from the field experiments. Addition of fresh fluid is quickly buffered by the flowing film, and dissolution due to acidity becomes less important for longer exposure lengths.

  15. Anaerobic respiration using a complete oxidative TCA cycle drives multicellular swarming in Proteus mirabilis.

    PubMed

    Alteri, Christopher J; Himpsl, Stephanie D; Engstrom, Michael D; Mobley, Harry L T

    2012-10-30

    Proteus mirabilis rapidly migrates across surfaces using a periodic developmental process of differentiation alternating between short swimmer cells and elongated hyperflagellated swarmer cells. To undergo this vigorous flagellum-mediated motility, bacteria must generate a substantial proton gradient across their cytoplasmic membranes by using available energy pathways. We sought to identify the link between energy pathways and swarming differentiation by examining the behavior of defined central metabolism mutants. Mutations in the tricarboxylic acid (TCA) cycle (fumC and sdhB mutants) caused altered patterns of swarming periodicity, suggesting an aerobic pathway. Surprisingly, the wild-type strain swarmed on agar containing sodium azide, which poisons aerobic respiration; the fumC TCA cycle mutant, however, was unable to swarm on azide. To identify other contributing energy pathways, we screened transposon mutants for loss of swarming on sodium azide and found insertions in the following genes that involved fumarate metabolism or respiration: hybB, encoding hydrogenase; fumC, encoding fumarase; argH, encoding argininosuccinate lyase (generates fumarate); and a quinone hydroxylase gene. These findings validated the screen and suggested involvement of anaerobic electron transport chain components. Abnormal swarming periodicity of fumC and sdhB mutants was associated with the excretion of reduced acidic fermentation end products. Bacteria lacking SdhB were rescued to wild-type pH and periodicity by providing fumarate, independent of carbon source but dependent on oxygen, while fumC mutants were rescued by glycerol, independent of fumarate only under anaerobic conditions. These findings link multicellular swarming patterns with fumarate metabolism and membrane electron transport using a previously unappreciated configuration of both aerobic and anaerobic respiratory chain components. Bacterial locomotion and the existence of microbes were the first scientific

  16. [Low molecular weight carboxylic acids in precipitation during the rainy season in the rural area of Anshun, West Guizhou Province].

    PubMed

    Zhang, Yan-Lin; Lee, Xin-Qing; Huang, Dai-Kuan; Huang, Rong-Sheng; Jiang, Wei

    2009-03-15

    40 rainwater samples were collected at Anshun from June 2007 to October 2007 and analysed in terms of pH values, electrical conductivity, major inorganic anions and soluble low molecular weight carboxylic acids. The results showed that pH of individual precipitation events ranged from 3.57-7.09 and the volume weight mean pH value was 4.57. The most abundant carboxylic acids were acetic (volume weight mean concentration 6.75 micromol x L(-1)) and formic (4.61 micromol x L(-1)) followed by oxalic (2.05 micromol x L(-1)). The concentration levels for these three species during summer especially June and July were comparatively high; it implied that organic acids in Anshun may came primarily from emissions from growing vegetations or products of the photochemical reactions of unsaturated hydrocarbons. Carboxylic acids were estimated to account for 32.2% to the free acidity in precipitation. The contribution was higher than in Guiyang rainwater, which indicated contamination by industry in Guiyang was more than in Anshun. The remarkable correlation(p = 0.01) between formic acid and acetic acid suggest that they have similar sources or similar intensity but different sources. And the remarkable correlation (p = 0.01) between and formic acid and oxalic acid showed that the precursors of oxalic acid and formic acid had similar sources. During this period, the overall wet deposition of carboxylic acids were 2.10 mmol/m2. And it appeared mainly in the summer, during which both concentration and contribution to free acidity were also relatively high. Consequently, it was necessary to control emission of organic acids in the summer to reduce frequence of acid rain in Anshun.

  17. Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

    NASA Technical Reports Server (NTRS)

    Muirhead, Dean; Carrier, Christopher

    2012-01-01

    In this study, three different mineral acids were substituted for sulfuric acid (H2SO4) in the urine stabilizer solution to eliminate the excess of sulfate ions in pretreated urine and assess the impact on maximum water recovery to avoid precipitation of minerals during distillation. The study evaluated replacing 98% sulfuric acid with 85% phosphoric acid (H3PO4), 37% hydrochloric acid (HCl), or 70% nitric acid (HNO3). The effect of lowering the oxidizer concentration in the pretreatment formulation also was studied. This paper summarizes the test results, defines candidate formulations for further study, and specifies the injection masses required to stabilize urine and minimize the risk of mineral precipitation during distillation. In the first test with a brine ersatz acidified with different acids, the solubility of calcium in gypsum saturated solutions was measured. The solubility of gypsum was doubled in the brines acidified with the alternative acids compared to sulfuric acid. In a second series of tests, the alternative acid pretreatment concentrations were effective at preventing precipitation of gypsum and other minerals up to 85% water recovery from 95th-percentile pretreated, augmented urine. Based on test results, phosphoric acid is recommended as the safest alternative to sulfuric acid. It also is recommended that the injected mass concentration of chromium trioxide solution be reduced by 75% to minimize liquid resupply mass by about 50%, reduce toxicity of brines, and reduce the concentration of organic acids in distillate. The new stabilizer solution formulations and required doses to stabilize urine and prevent precipitation of minerals up to 85% water recovery are given. The formulations in this study were tested on a limited number of artificially augmented urine batches collected from employees at the Johnson Space Center (JSC). This study successfully demonstrated that the desired physical and chemical stability of pretreated urine and brines

  18. Effect of acid precipitation on retention and excretion of elements in man.

    PubMed

    Bensryd, I; Rylander, L; Högstedt, B; Aprea, P; Bratt, I; Fåhraéus, C; Holmén, A; Karlsson, A; Nilsson, A; Svensson, B L

    1994-05-01

    From a population of 8918 farmers, 237 were selected whose consumption of locally produced foods was high. The subjects' water sources, private wells, were of different degrees of acidity. Significant associations between pH (median 6.7, range 4.7-8.6) of the drinking water and element concentrations were found. The correlation was negative for aluminium (Al; median 0.07 mumol/l), cadmium (Cd; 0.44 nmol/l), copper (Cu; 0.24 mumol/l) and lead (Pb; 1.9 nmol/l), and positive for calcium (Ca; 0.62 mmol/l) and magnesium (Mg; 0.21 mmol/l). Associations could not be found between the pH of, or element concentrations in, the water and concentrations of A1 (0.17 mumol/l), Mg (0.86 mmol/l) and selenium (Se; 1.0 mumol/l) in plasma, Cd (2.0 nmol/l), Pb (0.19 mumol/l) and mercury (Hg; 13 nmol/l) in blood, or A1 (12 mumol/mol creatinine) and Cu (11 mumol/mol creatinine) in urine. The concentrations of Hg in blood and Se in plasma were related to fish consumption, Cd and Pb in blood to smoking, A1 in urine to antacid intake, Pb in blood to rifle activities and hunting, and Hg in blood to hunting. Acid precipitation has an effect on element concentrations in drinking water, but not on the retention of those elements in the subjects investigated.

  19. Precipitation of arsenic sulphide from acidic water in a fixed-film bioreactor.

    PubMed

    Battaglia-Brunet, Fabienne; Crouzet, Catherine; Burnol, André; Coulon, Stéphanie; Morin, Dominique; Joulian, Catherine

    2012-08-01

    Arsenic (As) is a toxic element frequently present in acid mine waters and effluents. Precipitation of trivalent arsenic sulphide in sulphate-reducing conditions at low pH has been studied with the aim of removing this hazardous element in a waste product with high As content. To achieve this, a 400m L fixed-film column bioreactor was fed continuously with a synthetic solution containing 100mg L(-1) As(V), glycerol and/or hydrogen, at pH values between 2.7 and 5. The highest global As removal rate obtained during these experiments was close to 2.5mg L(-1)h(-1). A switch from glycerol to hydrogen when the biofilm was mature induced an abrupt increase in the sulphate-reducing activity, resulting in a dramatic mobilisation of arsenic due to the formation of soluble thioarsenic complexes. A new analytical method, based on ionic chromatography, was used to evaluate the proportion of As present as thioarsenic complexes in the bioreactor. Profiles of pH, total As and sulphate concentrations suggest that As removal efficiency was linked to solubility of orpiment (As(2)S(3)) depending on pH conditions. Molecular fingerprints revealed fairly homogeneous bacterial colonisation throughout the reactor. The bacterial community was diverse and included fermenting bacteria and Desulfosporosinus-like sulphate-reducing bacteria. arrA genes, involved in dissimilatory reduction of As(V), were found and the retrieved sequences suggested that As(V) was reduced by a Desulfosporosinus-like organism. This study was the first to show that As can be removed by bioprecipitation of orpiment from acidic solution containing up to 100mg L(-1) As(V) in a bioreactor.

  20. Effect of acid precipitation on retention and excretion of elements in man.

    PubMed

    Bensryd, I; Rylander, L; Högstedt, B; Aprea, P; Bratt, I; Fåhraéus, C; Holmén, A; Karlsson, A; Nilsson, A; Svensson, B L

    1994-05-01

    From a population of 8918 farmers, 237 were selected whose consumption of locally produced foods was high. The subjects' water sources, private wells, were of different degrees of acidity. Significant associations between pH (median 6.7, range 4.7-8.6) of the drinking water and element concentrations were found. The correlation was negative for aluminium (Al; median 0.07 mumol/l), cadmium (Cd; 0.44 nmol/l), copper (Cu; 0.24 mumol/l) and lead (Pb; 1.9 nmol/l), and positive for calcium (Ca; 0.62 mmol/l) and magnesium (Mg; 0.21 mmol/l). Associations could not be found between the pH of, or element concentrations in, the water and concentrations of A1 (0.17 mumol/l), Mg (0.86 mmol/l) and selenium (Se; 1.0 mumol/l) in plasma, Cd (2.0 nmol/l), Pb (0.19 mumol/l) and mercury (Hg; 13 nmol/l) in blood, or A1 (12 mumol/mol creatinine) and Cu (11 mumol/mol creatinine) in urine. The concentrations of Hg in blood and Se in plasma were related to fish consumption, Cd and Pb in blood to smoking, A1 in urine to antacid intake, Pb in blood to rifle activities and hunting, and Hg in blood to hunting. Acid precipitation has an effect on element concentrations in drinking water, but not on the retention of those elements in the subjects investigated. PMID:8016632

  1. Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

    PubMed Central

    Qiu, S M; Wen, G; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline calcium hydroxyapatite. This inhibition was not mediated by decreased Ca2+ activity. Taurocholic acid (2-12 mM) did not affect hydroxyapatite formation, but antagonized glycochenodeoxycholic acid. Both amorphous and crystalline precipitates contained a surface fraction relatively rich in phosphate. The surface phosphate content was diminish by increasing glycochenodeoxycholic acid concentrations, and this relationship was interpreted as competition between bile acid and HPO4(-4) for binding sites on the calcium phosphate surface. A phosphate-rich crystal surface was associated with rapid transition from amorphous to crystalline states. These results indicate that glycochenodeoxycholic acid prevents transformation of amorphous calcium phosphate to crystalline hydroxyapatite by competitively inhibiting the accumulation of phosphate on the crystal embryo surface. PMID:1655828

  2. The Role of Poly(Aspartic Acid) in the Precipitation of Calcium Phosphate in Confinement

    PubMed Central

    Cantaert, Bram; Beniash, Elia

    2013-01-01

    Many questions remain regarding the formation of ultrathin hydroxapatite (HAP) crystals within the confines of collagen fibrils of bones. These structures form through the interplay of the collagen matrix and non-collagenous proteins, and in vitro mineralization studies employing poly(aspartic acid) (PAsp) as a mimic of the non-collagenous proteins have generated mineralized fibrils with structures comparable to their biogenic counterparts. In this article, we employ the nanoscale cylindrical pores perforating track-etch filtration membranes to investigate the role of PAsp in controlling the infiltration and crystallization of calcium phosphate (CaP) within confined volumes. Oriented polycrystalline HAP and non-oriented octacalcium phosphate (OCP) rods precipitated within the membrane pores via an amorphous calcium phosphate (ACP) precursor, where PAsp increased the proportion of OCP rods. Further, ACP crystallized faster within the membranes than in bulk solution when PAsp was present, suggesting that PAsp inhibits crystallization in solution, but promotes it when bound to a substrate. Finally, in contrast to the collagen system, PAsp reduced the yield of intra-membrane mineral and failed to enhance infiltration. This suggests that a specific interaction between the collagen matrix and ACP/PAsp precursor particles drives effective infiltration. Thus, while orientation of HAP crystals can be achieved by confinement alone, the chemistry of the collagen matrix is necessary for efficient mineralisation with CaP. PMID:24409343

  3. Geological and hydrochemical sensitivity of the eastern United States to acid precipitation

    SciTech Connect

    Hendrey, G.R.; Galloway, J.N.; Norton, S.A.; Schofield, C.L.; Shaffer, P.W.; Burns, D.A.

    1980-03-01

    A new analysis of bedrock geology maps of the eastern US constitutes a simple model for predicting areas which might be impacted by acid precipitation and it allows much greater resolution for detecting sensitivity than has previously been available for the region. Map accuracy has been verified by examining current alkalinities and pH's of waters in several test states, including Maine, New Hampshire, New York, Virginia and North Carolina. In regions predicted to be highly sensitive, alkalinities in upstream sites were generally low. Many areas of the eastern US are pinpointed in which some of the surface waters, especially upstream reaches, may be sensitive to acidification. Pre-1970 data were compared to post-1975 data, revealing marked declines in both alkalinity and pH of sensitive waters of two states tested, North Carolina, where pH and alkalinity have decreased in 80% of 38 streams and New Hampshire, where pH in 90% of 49 streams and lakes has decreased since 1949. These sites are predicted to be sensitive by the geological map on the basis of their earlier alkalinity values. The map is to be improved by the addition of a soils component.

  4. Interactions of 57Co, 85Sr and 137Cs with peat under acidic precipitation conditions.

    PubMed

    Sanchez, A L; Schell, W R; Thomas, E D

    1988-03-01

    Following the burial of low-level wastes in nuclear waste repositories, the interactions of radionuclides with surrounding soil infiltrated by acid precipitation could cause radionuclide migration and transport into nearby wells. To evaluate this migration through organically rich soil in the unsaturated zone, we measured sorption and desorption distribution ratios (Rd) of 57Co, 85Sr and 137Cs onto peat at pH 4. Peat samples rich in organic C showed relatively higher sorption Rd values for 57Co and 85Sr compared to soil samples with less organic C. The sorption and desorption Rd values for these radionuclides are similar, indicating the reversibility of the sorption process. The measurements suggest the importance of organic complexes for the retention of these radionuclides at the pH range (pH 4), where hydrolysis of the metals is not important and sorption is expected to be low. Cesium-137, on the other hand, appears to be associated more strongly with inorganic components of the soil samples, with its Rd value significantly higher in the peat material containing less organic C. The 137Cs desorption Rd on the same peat sample is also comparable to the sorption Rd indicating equilibrium. Both the organic and inorganic components of peat are thus able to retard the migration of radionuclides which may be found in nuclear waste repositories. The design of such a repository may be improved using a peat barrier to restrict radionuclide migration.

  5. Glutamine oxidation maintains the TCA cycle and cell survival during impaired mitochondrial pyruvate transport.

    PubMed

    Yang, Chendong; Ko, Bookyung; Hensley, Christopher T; Jiang, Lei; Wasti, Ajla T; Kim, Jiyeon; Sudderth, Jessica; Calvaruso, Maria Antonietta; Lumata, Lloyd; Mitsche, Matthew; Rutter, Jared; Merritt, Matthew E; DeBerardinis, Ralph J

    2014-11-01

    Alternative modes of metabolism enable cells to resist metabolic stress. Inhibiting these compensatory pathways may produce synthetic lethality. We previously demonstrated that glucose deprivation stimulated a pathway in which acetyl-CoA was formed from glutamine downstream of glutamate dehydrogenase (GDH). Here we show that import of pyruvate into the mitochondria suppresses GDH and glutamine-dependent acetyl-CoA formation. Inhibiting the mitochondrial pyruvate carrier (MPC) activates GDH and reroutes glutamine metabolism to generate both oxaloacetate and acetyl-CoA, enabling persistent tricarboxylic acid (TCA) cycle function. Pharmacological blockade of GDH elicited largely cytostatic effects in culture, but these effects became cytotoxic when combined with MPC inhibition. Concomitant administration of MPC and GDH inhibitors significantly impaired tumor growth compared to either inhibitor used as a single agent. Together, the data define a mechanism to induce glutaminolysis and uncover a survival pathway engaged during compromised supply of pyruvate to the mitochondria.

  6. Reductive photo-dechlorination (RPD) technology for remediation of TCA

    SciTech Connect

    Lavid, M.; Gulati, S.K.; Teytelboym, M.

    1994-12-31

    The Reductive Photo-Dechlorination (RPD) technology uses ultraviolet light in a reducing atmosphere to remove chlorine atoms from organo-chlorine waste streams at low to moderate temperatures. Because chlorinated organics are destroyed in a reducing environment, process products include valuable hydrocarbons and hydrogen chloride with no toxic oxygenated chlorocarbon by-products. The RPD process is designed specifically to treat volatile chlorinated wastes in the liquid or gaseous phases. Field applications include organic wastes produced from soil venting operations and those adsorbed on activated carbon. The process can also be used to pretreat gas streams entering catalytic oxidation systems, reducing chlorine content and hereby protecting the catalyst against poisoning. This paper focuses on photo-thermal remediation of 1,1,1-trichloroethane (TCA). It describes bench-scale experimental results, kinetic modeling predictions, and selected design parameters for a pilot-scale demonstration.

  7. Survival of Listeria innocua in rainbow trout protein recovered by isoelectric solubilization and precipitation with acetic and citric acids.

    PubMed

    Otto, R A; Paker, I; Bane, L; Beamer, S; Jaczynski, J; Matak, K E

    2011-08-01

    During mechanical fish processing, a substantial amount of protein is discarded as by-products. Isoelectric solubilization and precipitation (ISP) is a process that uses extreme pH shifts to solubilize and precipitate protein from by-products to recover previously discarded protein. Typically, strong acids are used for pH reduction, but these acids do not have a pasteurization effect (6 log reduction) on bacterial load; therefore, organic acids were used during ISP processing to test the impact on Listeria innocua concentrations. Headed and gutted rainbow trout (Oncorhynchus mykiss) were inoculated with L. innocua, homogenized, and brought to the target pH with granular citric acid (pH 2.0 and 2.5) or glacial acetic acid (pH 3.0 and 3.5). Proteins were solubilized for 10 min at 4°C, and insoluble components (e.g., skin and insoluble protein) were removed by centrifugation. The remaining solution was pH shifted to the protein isoelectric point (pH 5.5) with sodium hydroxide, and precipitated protein was separated from the water. Microbial cells for each component (proteins, insolubles, and water) were enumerated on modified Oxford agar (MOX) and tryptic soy agar with 6% yeast extract (TSAYE). The sums of the surviving cells from each component were compared with the initial inoculum levels. No significant differences were observed between results obtained from TSAYE and from MOX (P > 0.05). Significant reductions in microbial populations were detected, regardless of pH or acid type (P < 0.05). The greatest reduction was at pH 3.0 with glacial acetic acid, resulting in a mean reduction of 6.41 log CFU/g in the recovered protein and 5.88 log CFU/g in the combined components. These results demonstrate the antimicrobial potential of organic acids in ISP processing.

  8. An evaluation of trends in the acidity of precipitation and the related acidification of surface water in North America

    USGS Publications Warehouse

    Turk, John T.

    1983-01-01

    The acidity of precipitation in the Northeastern United States and Southeastern Canada has increased in the past, probably as a result of anthropogenic emissions. The increase in New England and New York occurred primarily before the mid-1950's. Since the mid1960's, there has been no significant change in the acidity of precipitation in this region; however, sulfate concentrations have decreased and nitrate concentrations may have increased. The time of initial acidification in Southeastern Canada is not known because of a lack of historical data. In the Southeastern United States, the evaluation of whether precipitation has been acidified is complicated by meager data. The available data show that precipitation is more acidic than would be expected for sites unaffected by anthropogenic emissions. In addition, comparison of recent data with the meager historical data suggests, but does not unambiguously prove, increased acidification since the 1950's. In the Western United States, available data indicate that precipitation at individual sites has been acidified by anthropogenic emissions. The acidification generally has been attributable to localized sources, and the time of initial acidification is undefined. Acidification of lakes and streams in the Northeastern United States has occurred in a time frame compatible with the hypothesis that acidification of precipitation was the cause. The acidification of surface waters appears to have occurred before the mid- to late 1960's. In Southeastern Canada, the best-documented cases of acidified lakes point to localized sources of acidic emissions as the cause. Sparse evidence of recent regional acidification of lakes and streams exists, but evidence for acidification of precipitation as the cause is largely lacking. In the Southeastern United States, most data on acidification of surface waters are ambiguous, and in the West, most of the data reflect local conditions. However, recent analysis of a national network of

  9. Potential effects of clean coal technologies on acid precipitation, greenhouse gases, and solid waste disposal

    SciTech Connect

    Blasing, T.J.; Miller, R.L.; McCold, L.N.

    1993-11-01

    The US Department of Energy`s (DOE`s) Clean Coal Technology Demonstration Program (CCTDP) was initially funded by Congress to demonstrate more efficient, economically feasible, and environmentally acceptable coal technologies. Although the environmental focus at first was on sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) because their relationship to acid precipitation, the CCTDP may also lead to reductions in carbon dioxide (CO{sub 2}) emissions and in the volume of solid waste produced, compared with conventional technologies. The environmental effects of clean coal technologies (CCTs) depend upon which (if any) specific technologies eventually achieve high acceptance in the marketplace. In general, the repowering technologies and a small group of retrofit technologies show the most promise for reducing C0{sub 2} emissions and solid waste. These technologies also compare favorably with other CCTs in terms of SO{sub 2} and NO{sub x} reductions. The upper bound for CO{sup 2} reductions in the year 2010 is only enough to reduce global ``greenhouse`` warming potential by about 1%. However, CO{sub 2} emissions come from such variety of sources around the globe that no single technological innovation or national policy change could realistically be expected to reduce these emissions by more than a few percent. Particular CCTs can lead to either increases or decreases in the amount of solid waste produced. However, even if decreases are not achieved, much of the solid waste from clean coal technologies would be dry and therefore easier to dispose of than scrubber sludge.

  10. Particle size tailoring of ursolic acid nanosuspensions for improved anticancer activity by controlled antisolvent precipitation.

    PubMed

    Wang, Yancai; Song, Ju; Chow, Shing Fung; Chow, Albert H L; Zheng, Ying

    2015-10-15

    The present study was aimed at tailoring the particle size of ursolic acid (UA) nanosuspension for improved anticancer activity. UA nanosuspensions were prepared by antisolvent precipitation using a four-stream multi-inlet vortex mixer (MIVM) under defined conditions of varying solvent composition, drug feeding concentration or stream flow rate. The resulting products were characterized for particle size and polydispersity. Two of the UA nanosuspensions with mean particle sizes of 100 and 300 nm were further assessed for their in-vitro activity against MCF-7 breast cancer cells using fluorescence microscopy with 4',6-diamidino-2-phenylindole (DAPI) staining, as well as flow cytometry with propidium (PI) staining and with double staining by fluorescein isothiocyanate. It was revealed that the solvent composition, drug feeding concentration and stream flow rate were critical parameters for particle size control of the UA nanosuspensions generated with the MIVM. Specifically, decreasing the UA feeding concentration or increasing the stream flow rate or ethanol content resulted in a reduction of particle size. Excellent reproducibility for nanosuspension production was demonstrated for the 100 and 300 nm UA preparations with a deviation of not more than 5% in particle size from the mean value of three independent batches. Fluorescence microscopy and flow cytometry revealed that these two different sized UA nanosuspensions, particularly the 300 nm sample, exhibited a higher anti-proliferation activity against the MCF-7 cells and afforded a larger population of these cells in both early and late apoptotic phases. In conclusion, MIVM is a robust and pragmatic tool for tailoring the particle size of the UA nanosuspension. Particle size appears to be a critical determinant of the anticancer activity of the UA nanoparticles.

  11. Particle size tailoring of ursolic acid nanosuspensions for improved anticancer activity by controlled antisolvent precipitation.

    PubMed

    Wang, Yancai; Song, Ju; Chow, Shing Fung; Chow, Albert H L; Zheng, Ying

    2015-10-15

    The present study was aimed at tailoring the particle size of ursolic acid (UA) nanosuspension for improved anticancer activity. UA nanosuspensions were prepared by antisolvent precipitation using a four-stream multi-inlet vortex mixer (MIVM) under defined conditions of varying solvent composition, drug feeding concentration or stream flow rate. The resulting products were characterized for particle size and polydispersity. Two of the UA nanosuspensions with mean particle sizes of 100 and 300 nm were further assessed for their in-vitro activity against MCF-7 breast cancer cells using fluorescence microscopy with 4',6-diamidino-2-phenylindole (DAPI) staining, as well as flow cytometry with propidium (PI) staining and with double staining by fluorescein isothiocyanate. It was revealed that the solvent composition, drug feeding concentration and stream flow rate were critical parameters for particle size control of the UA nanosuspensions generated with the MIVM. Specifically, decreasing the UA feeding concentration or increasing the stream flow rate or ethanol content resulted in a reduction of particle size. Excellent reproducibility for nanosuspension production was demonstrated for the 100 and 300 nm UA preparations with a deviation of not more than 5% in particle size from the mean value of three independent batches. Fluorescence microscopy and flow cytometry revealed that these two different sized UA nanosuspensions, particularly the 300 nm sample, exhibited a higher anti-proliferation activity against the MCF-7 cells and afforded a larger population of these cells in both early and late apoptotic phases. In conclusion, MIVM is a robust and pragmatic tool for tailoring the particle size of the UA nanosuspension. Particle size appears to be a critical determinant of the anticancer activity of the UA nanoparticles. PMID:26302857

  12. PRECP: the Department of Energy's program on the nonlinearity of acid precipitation processes

    SciTech Connect

    Tanner, R.L.; Tichler, J.; Brown, R.; Davis, W.; Johnson, S.; Patrinos, A.A.N.; Sisterson, D.; Slinn, W.G.N.

    1986-09-01

    During the period of 1 April to 3 May 1985, staff from Argonne National Laboratory (ANL), Brookhaven National Laboratory (BNL), and Pacific Northwest Laboratory (PNL), participated in a multifaceted, coordinated set of field studies from an aircraft logistical base in Columbus, OH, and a surface precipitation and air chemistry network in the Philadelphia area. The general goals of these activities, conducted within the DOE-sponsored PRocessing of Emissions by Clouds and Precipitation (PRECP) program were to obtain information concerning scavenging ratios and the vertical distribution of cloud and precipitation chemistry for sulfur and nitrogen oxides and oxyacids, and for oxidant species in the vicinity of precipitating and nonprecipitating clouds. Profiling of pollutant concentrations and phase distributions, and studies of scavenging processes were accomplished principally by airborne measurements of aerosol and gaseous species in pre-cloud and below-cloud air and of aqueous-phase species in clouds and precipitation, accompanied by documentation of meteorological and cloud physics parameters in the sampled regimes. Studies in the Midwest utilized only limited surface precipitation collection and chemical measurements, whereas a more extensive ground precipitation network was deployed in the Philadelphia area studies together with surface air chemistry measurements at a single nonurban site.

  13. STRONTIUM PRECIPITATION

    DOEpatents

    McKenzie, T.R.

    1960-09-13

    A process is given for improving the precipitation of strontium from an aqueous phosphoric-acid-containing solution with nickel or cobalt ferrocyanide by simultaneously precipitating strontium or calcium phosphate. This is accomplished by adding to the ferrocyanide-containing solution calcium or strontium nitrate in a quantity to yield a concentration of from 0.004 to 0.03 and adjusting the pH of the solution to a value of above 8.

  14. Stepwise ethanolic precipitation of sugar beet pectins from the acidic extract.

    PubMed

    Guo, Xiaoming; Meng, Hecheng; Zhu, Siming; Tang, Qiang; Pan, Runquan; Yu, Shujuan

    2016-01-20

    A stepwise ethanol-precipitation (SEP) procedure was developed for the purification of sugar beet pectins (SBP) from a pectin-containing aqueous extract. Five fractions of different chemical and molecular characteristics were produced by stepwise elevating the alcohol concentration of the precipitation medium from 50% to 80% v/v. Comparison of chemical and macromolecular features between the obtained fractions indirectly suggested that the ability of pectin to solubilize in the ethanol-water binary mixture depended greatly on the polymer structure. Fractions rich in neutral sugars were precipitated at relatively high ethanol concentrations, probably due to the enhanced interactions generated between pectin side chains and solvent molecules. Furthermore, the obtained fractions displayed different surface activities. Results obtained in this work indicate that the SEP procedure is more selective with respect to pectin structural features and surface properties than the one-step ethanolic precipitation.

  15. Stepwise ethanolic precipitation of sugar beet pectins from the acidic extract.

    PubMed

    Guo, Xiaoming; Meng, Hecheng; Zhu, Siming; Tang, Qiang; Pan, Runquan; Yu, Shujuan

    2016-01-20

    A stepwise ethanol-precipitation (SEP) procedure was developed for the purification of sugar beet pectins (SBP) from a pectin-containing aqueous extract. Five fractions of different chemical and molecular characteristics were produced by stepwise elevating the alcohol concentration of the precipitation medium from 50% to 80% v/v. Comparison of chemical and macromolecular features between the obtained fractions indirectly suggested that the ability of pectin to solubilize in the ethanol-water binary mixture depended greatly on the polymer structure. Fractions rich in neutral sugars were precipitated at relatively high ethanol concentrations, probably due to the enhanced interactions generated between pectin side chains and solvent molecules. Furthermore, the obtained fractions displayed different surface activities. Results obtained in this work indicate that the SEP procedure is more selective with respect to pectin structural features and surface properties than the one-step ethanolic precipitation. PMID:26572361

  16. Preliminary Results of the 1.5% TCA (Modular) Controls Model in the NASA Langley UPWT

    NASA Technical Reports Server (NTRS)

    Kubiatko, Paul; McMillin, Naomi; Cameron, Douglas C.

    1999-01-01

    To summarize the significant highlights in this report: (1) Data quality, determined by multiple repeat runs performed on the TCA baseline configuration, and long-term repeatability, determined by comparing baseline Reference H data from this test to a previous test, have been shown to be good. (2) The longitudinal stability of the TCA is more non-linear than for the Reference H, and while it is similar at normal lift values, the TCA has considerably more pitch-up at higher lift. (3) Longitudinal control effectiveness of the TCA is similar to the Reference H and the ratio of elevator effectiveness to horizontal tail effectiveness is approximately 0.3. (4) The directional stability of the TCA is improved relative to Reference H at higher angles-of attack. The chine is effective for improving directional stability.

  17. Respiratory and TCA cycle activities affect S. cerevisiae lifespan, response to caloric restriction and mtDNA stability.

    PubMed

    Tahara, Erich B; Cezário, Kizzy; Souza-Pinto, Nadja C; Barros, Mario H; Kowaltowski, Alicia J

    2011-10-01

    We studied the importance of respiratory fitness in S. cerevisiae lifespan, response to caloric restriction (CR) and mtDNA stability. Mutants harboring mtDNA instability and electron transport defects do not respond to CR, while tricarboxylic acid cycle mutants presented extended lifespans due to CR. Interestingly, mtDNA is unstable in cells lacking dihydrolipoyl dehydrogenase under CR conditions, and cells lacking aconitase under standard conditions (both enzymes are components of the TCA and mitochondrial nucleoid). Altogether, our data indicate that respiratory integrity is required for lifespan extension by CR and that mtDNA stability is regulated by nucleoid proteins in a glucose-sensitive manner.

  18. Effects of airborne particulate matter on the acidity of precipitation in central Missouri

    SciTech Connect

    Applin, K.R.

    1985-01-01

    The pH of rainfall in central Missouri was monitored at four sites during the fall of 1983. Several pH values were well above 5.6, the theoretical pH of pure water in equilibrium with ambient levels of CO/sub 2/. Most of the higher pH's were measured on rainfall of short duration or rainfall collected during the first few hours of extended rainfall events. Furthermore, the rainfall associated with storm events lasting several days exhibited a trend of decreasing pH with time approaching values as low as 4.0 during the late stages of rainfall. Precipitation pH values above 5.6 apparently reflect neutralization reactions between wet precipitation and various components of airborne dust, especially clays and carbonates. During extended rainfalls, the neutralization effects gradually diminish as suspended dust is washed from the atmosphere yielding more accurate values of the wet precipitation pH. The results of this study suggest that airborne particulate matter generated from the dust bowl region of the US may affect the chemistry of precipitation in areas hundreds of kilometers downwind. Using date available in the literature, a direct relationship between precipitation pH and accumulated dustfall was found for data taken along a transect which represents the path of major storms crossing the US, i.e., from the south-central to northeastern regions.

  19. Dissolved, particulate and acid-leachable trace metal concentrations in North Atlantic precipitation collected on the Global Change Expedition

    SciTech Connect

    Lim, B.; Jickells, T.D. )

    1990-12-01

    Atmospheric inputs of trace metals into surface waters are an important pathway for the oceanic biogeochemical cycling of many trace constituents. Rainwater samples from six precipitation events were collected on board ship during legs 3 and 4 of the Global Change Expedition over the North Atlantic Ocean and analyzed for dissolved, particulate (Al and Pb), and acid-leachable trace metals (Al, Fe, Mn, Cd, Cu, Pb, Zn). Acid-leachable concentrations of the elements were similar to reported values from the North Atlantic and Pacific Oceans which were measured using comparable acidification procedures. Concentrations of dissolved and particulate Al and Pb were determined in rain events acid-leachable and total trace metal concentrations suggest that the acid-leachable fraction of metals can significantly underestimate total concentrations of crustal elements in rain. The solubilities of Al and Pb in precipitation were variable and mean solubilities of the elements were 13% and 45%, respectively. Recycled sea salt components were less than 14% for Al, Fe, Mn, Pb, Cd, Cu, and Zn, indicating that the net trace metal flux is from the atmosphere to the oceans. Deep sea particle fluxes for these metals through the western tropical North Atlantic exceed atmospheric deposition fluxes by a factor of 18 to 41. 57 refs., 2 figs., 12 tabs.

  20. Adsorption and co-precipitation behavior of arsenate, chromate, selenate and boric acid with synthetic allophane-like materials.

    PubMed

    Opiso, Einstine; Sato, Tsutomu; Yoneda, Tetsuro

    2009-10-15

    Pollution caused by boric acid and toxic anions such as As(V), Cr(VI) and Se(VI) is hazardous to human health and environment. The sorption characteristics of these environmentally significant ionic species on allophane-like nanoparticles were investigated in order to determine whether allophane can reduce their mobility in the subsurface environment at circum-neutral pH condition. Solutions containing 100 or 150 mmol of AlCl(3)x6H(2)O were mixed to 100 mmol of Na(4)SiO(4) and the pH were adjusted to 6.4+/-0.3. The mineral suspensions were shaken for 1h and incubated at 80 degrees C for 5 days. Appropriate amounts of As, B, Cr and Se solutions were added separately during and after allophane precipitation. The results showed that As(V) and boric acid can be irreversibly fixed during co-precipitation in addition to surface adsorption. However, Cr(VI) and Se(VI) retention during and after allophane precipitation is mainly controlled by surface adsorption. The structurally fixed As(V) and boric acid were more resistant to release than those bound on the surface. The sorption characteristics of oxyanions and boric acid were also influenced by the final Si/Al molar ratio of allophane in which Al-rich allophane tend to have higher uptake capacity. The overall results of this study have demonstrated the role of allophane-like nanoparticles and the effect of its Si/Al ratio on As, B, Cr and Se transport processes in the subsurface environment.

  1. Preliminary Results of the 1.5% TCA (Modular) Controls Model in the NASA Langley UPWT

    NASA Technical Reports Server (NTRS)

    Kubiatko, Paul; McMillin, Naomi; Cameron, Douglas C.

    1999-01-01

    To summarize the significant highlights in this report: (1) Data quality, determined by multiple repeat runs performed on the TCA baseline configuration, and long-term repeatability, determined by comparing baseline Reference H data from this test to a previous test, have been shown to be good. (2) The longitudinal stability of the TCA is more non-linear than for the Reference H, and while it is similar at normal lift values, the TCA has considerably more pitch-up at higher lift. (3) Longitudinal control effectiveness of the TCA is similar to the Reference H and the ratio of elevator effectiveness to horizontal tail effectiveness is approximately 0.3. 4) The directional stability of the TCA is improved relative to Reference H at higher angles-of attack. The chine is effective for improving directional stability. (5) The directional control effectiveness 'of the TCA rudder is the same as that of the Reference H rudder at low angles-of-attack, after taking factors, such as number of rudder panels deflected and vertical tail volume into account. However, rudder effectiveness was shown to be reduced at higher angles-of-attack. (6) The lateral stability was shown to be reduced relative to the Reference H, which may be beneficial at low speeds for alleviating lateral control saturation. (7) Lateral control effectiveness for the TCA was shown to be similar to the Reference H for negative trailing-edge flap deflections and was reduced by approximately 25% for positive trailing-edge flap deflections.

  2. Trichloroacetic acid cycling in Sitka spruce saplings and effects on sapling health following long term exposure.

    PubMed

    Dickey, C A; Heal, K V; Stidson, R T; Koren, R; Schröder, P; Cape, J N; Heal, M R

    2004-07-01

    Trichloroacetic acid (TCA, CCl(3)COOH) has been associated with forest damage but the source of TCA to trees is poorly characterised. To investigate the routes and effects of TCA uptake in conifers, 120 Sitka spruce (Picea sitchensis (Bong.) Carr) saplings were exposed to control, 10 or 100 microg l(-1) solutions of TCA applied twice weekly to foliage only or soil only over two consecutive 5-month growing seasons. At the end of each growing season similar elevated TCA concentrations (approximate range 200-300 ng g(-1) dwt) were detected in both foliage and soil-dosed saplings exposed to 100 microg l(-1) TCA solutions showing that TCA uptake can occur from both exposure routes. Higher TCA concentrations in branchwood of foliage-dosed saplings suggest that atmospheric TCA in solution is taken up indirectly into conifer needles via branch and stemwood. TCA concentrations in needles declined slowly by only 25-30% over 6 months of winter without dosing. No effect of TCA exposure on sapling growth was measured during the experiment. However at the end of the first growing season needles of saplings exposed to 10 or 100 microg l(-1) foliage-applied TCA showed significantly more visible damage, higher activities of some detoxifying enzymes, lower protein contents and poorer water control than needles of saplings dosed with the same TCA concentrations to the soil. At the end of each growing season the combined TCA storage in needles, stemwood, branchwood and soil of each sapling was <6% of TCA applied. Even with an estimated half-life of tens of days for within-sapling elimination of TCA during the growing season, this indicates that TCA is eliminated rapidly before uptake or accumulates in another compartment. Although TCA stored in sapling needles accounted for only a small proportion of TCA stored in the sapling/soil system it appears to significantly affect some measures of sapling health.

  3. Biogeochemical effects of forest vegetation on acid precipitation-related water chemistry: a case study in southwest China.

    PubMed

    Chen, Jing; Li, Wei; Gao, Fang

    2010-10-01

    The elemental composition of rainwater, throughfall, and soil solutions of a forest ecosystem in the acid rain control region of southwest China was investigated during 2007-2008 to assess the acid buffering capacity of different forest covers. A possible seasonal distribution of wet deposition was identified. Sulfur was determined as the dominant acidification precursor in this region. The chemical composition of rainfall intercepted by the forest canopy was modified substantially; generally the ion concentrations were increased by dry deposition and foliar leaching. As an exception, the concentration of NH(4)(+) and NO(3)(-) decreased in throughfall, which was probably due to the absorption of nitrogen by the leaves. Elemental concentrations in soil solutions decreased with depth. The water conservation capacity of different forests was also evaluated. The most appropriate forest vegetation for water conservation and remediation of acid precipitation in this region was explored for the sake of ecosystem management, ecological restoration and economic development.

  4. Biogeochemical effects of forest vegetation on acid precipitation-related water chemistry: a case study in southwest China.

    PubMed

    Chen, Jing; Li, Wei; Gao, Fang

    2010-10-01

    The elemental composition of rainwater, throughfall, and soil solutions of a forest ecosystem in the acid rain control region of southwest China was investigated during 2007-2008 to assess the acid buffering capacity of different forest covers. A possible seasonal distribution of wet deposition was identified. Sulfur was determined as the dominant acidification precursor in this region. The chemical composition of rainfall intercepted by the forest canopy was modified substantially; generally the ion concentrations were increased by dry deposition and foliar leaching. As an exception, the concentration of NH(4)(+) and NO(3)(-) decreased in throughfall, which was probably due to the absorption of nitrogen by the leaves. Elemental concentrations in soil solutions decreased with depth. The water conservation capacity of different forests was also evaluated. The most appropriate forest vegetation for water conservation and remediation of acid precipitation in this region was explored for the sake of ecosystem management, ecological restoration and economic development. PMID:20859590

  5. Precipitation of jarosite-type double salts from spent acid solutions from a chemical coal cleaning process

    SciTech Connect

    Norton, G.

    1990-09-21

    The precipitation of jarosite compounds to remove Na, K, Fe, and SO{sub 4}{sup 2{minus}} impurities from spent acid solutions from a chemical coal cleaning process was studied. Simple heating of model solutions containing Fe{sub 2}(SO{sub 4}){sub 3}, Na{sub 2}SO{sub 4}, and K{sub 2}SO{sub 4} caused jarosite (KFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}) to form preferentially to natrojarosite (NaFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}). Virtually all of the K, about 90% of the Fe, and about 30% of the SO{sub 4}{sup 2{minus}} could be precipitated from those solutions at 95{degree}C, while little or no Na was removed. However, simple heating of model solutions containing only Fe{sub 2}(SO{sub 4}){sub 3} and Na{sub 2}SO{sub 4} up to 95{degree}C for {le}12 hours produced low yields of jarosite compounds, and the Fe concentration in the solution had to be increased to avoid the formation of undesirable Fe compounds. Precipitate yields could be increased dramatically in model solutions of Na{sub 2}SO{sub 4}/Fe{sub 2}(SO{sub 4}){sub 3} containing excess Fe by using either CaCO{sub 3}, Ca(OH){sub 2}, or ZnO to neutralize H{sub 2}SO{sub 4} released during hydrolysis of the Fe{sub 2}(SO{sub 4}){sub 3} and during the precipitation reactions. Results obtained from the studies with model solutions were applied to spent acids produced during laboratory countercurrent washing of coal which had been leached with a molten NaOH/KOH mixture. Results indicated that jarosite compounds can be precipitated effectively from spent acid solutions by heating for 6 hours at 80{degree}C while maintaining a pH of about 1.5 using CaCO{sub 3}.

  6. A Process-Based Model of TCA Cycle Functioning to Analyze Citrate Accumulation in Pre- and Post-Harvest Fruits.

    PubMed

    Etienne, Audrey; Génard, Michel; Bugaud, Christophe

    2015-01-01

    Citrate is one of the most important organic acids in many fruits and its concentration plays a critical role in organoleptic properties. The regulation of citrate accumulation throughout fruit development, and the origins of the phenotypic variability of the citrate concentration within fruit species remain to be clarified. In the present study, we developed a process-based model of citrate accumulation based on a simplified representation of the TCA cycle to predict citrate concentration in fruit pulp during the pre- and post-harvest stages. Banana fruit was taken as a reference because it has the particularity of having post-harvest ripening, during which citrate concentration undergoes substantial changes. The model was calibrated and validated on the two stages, using data sets from three contrasting cultivars in terms of citrate accumulation, and incorporated different fruit load, potassium supply, and harvest dates. The model predicted the pre and post-harvest dynamics of citrate concentration with fairly good accuracy for the three cultivars. The model suggested major differences in TCA cycle functioning among cultivars during post-harvest ripening of banana, and pointed to a potential role for NAD-malic enzyme and mitochondrial malate carriers in the genotypic variability of citrate concentration. The sensitivity of citrate accumulation to growth parameters and temperature differed among cultivars during post-harvest ripening. Finally, the model can be used as a conceptual basis to study citrate accumulation in fleshy fruits and may be a powerful tool to improve our understanding of fruit acidity.

  7. A Process-Based Model of TCA Cycle Functioning to Analyze Citrate Accumulation in Pre- and Post-Harvest Fruits.

    PubMed

    Etienne, Audrey; Génard, Michel; Bugaud, Christophe

    2015-01-01

    Citrate is one of the most important organic acids in many fruits and its concentration plays a critical role in organoleptic properties. The regulation of citrate accumulation throughout fruit development, and the origins of the phenotypic variability of the citrate concentration within fruit species remain to be clarified. In the present study, we developed a process-based model of citrate accumulation based on a simplified representation of the TCA cycle to predict citrate concentration in fruit pulp during the pre- and post-harvest stages. Banana fruit was taken as a reference because it has the particularity of having post-harvest ripening, during which citrate concentration undergoes substantial changes. The model was calibrated and validated on the two stages, using data sets from three contrasting cultivars in terms of citrate accumulation, and incorporated different fruit load, potassium supply, and harvest dates. The model predicted the pre and post-harvest dynamics of citrate concentration with fairly good accuracy for the three cultivars. The model suggested major differences in TCA cycle functioning among cultivars during post-harvest ripening of banana, and pointed to a potential role for NAD-malic enzyme and mitochondrial malate carriers in the genotypic variability of citrate concentration. The sensitivity of citrate accumulation to growth parameters and temperature differed among cultivars during post-harvest ripening. Finally, the model can be used as a conceptual basis to study citrate accumulation in fleshy fruits and may be a powerful tool to improve our understanding of fruit acidity. PMID:26042830

  8. A Process-Based Model of TCA Cycle Functioning to Analyze Citrate Accumulation in Pre- and Post-Harvest Fruits

    PubMed Central

    Etienne, Audrey; Génard, Michel; Bugaud, Christophe

    2015-01-01

    Citrate is one of the most important organic acids in many fruits and its concentration plays a critical role in organoleptic properties. The regulation of citrate accumulation throughout fruit development, and the origins of the phenotypic variability of the citrate concentration within fruit species remain to be clarified. In the present study, we developed a process-based model of citrate accumulation based on a simplified representation of the TCA cycle to predict citrate concentration in fruit pulp during the pre- and post-harvest stages. Banana fruit was taken as a reference because it has the particularity of having post-harvest ripening, during which citrate concentration undergoes substantial changes. The model was calibrated and validated on the two stages, using data sets from three contrasting cultivars in terms of citrate accumulation, and incorporated different fruit load, potassium supply, and harvest dates. The model predicted the pre and post-harvest dynamics of citrate concentration with fairly good accuracy for the three cultivars. The model suggested major differences in TCA cycle functioning among cultivars during post-harvest ripening of banana, and pointed to a potential role for NAD-malic enzyme and mitochondrial malate carriers in the genotypic variability of citrate concentration. The sensitivity of citrate accumulation to growth parameters and temperature differed among cultivars during post-harvest ripening. Finally, the model can be used as a conceptual basis to study citrate accumulation in fleshy fruits and may be a powerful tool to improve our understanding of fruit acidity. PMID:26042830

  9. Effect of precipitation, geographical location and biosynthesis on New Zealand milk powder bulk and fatty acids D/H ratios

    NASA Astrophysics Data System (ADS)

    Frew, R.; Emad Ehtesham, R.; Van Hale, R.; Hayman, A.; Baisden, T.

    2012-04-01

    D/H ratio measurements provide useful information for the investigation of biogeochemical influences on natural and agricultural produce, particularly with application to food traceability and authentication. Numerous studies have shown that variation of a product's D/H ratio is influenced by both environmental factors and biological processes. This study investigates the D/H ratio of New Zealand milk powder and individual fatty acids, and causal determinants of isotopic variation. One of the key environmental factors is precipitation, and the D/H ratio "isoscaping" of NZ has been undertaken. New Zealand provides a unique geography for these kinds of study in terms of proximity to the ocean and natural geographical variability from sea level to elevations as high as 3700 m. Milk powder samples were collected from different geographical regions from milk processing units, which were supplied by producers in the immediate region. H/D ratios of bulk milk powder and of individual fatty acids were determined. Initial comparison of the precipitation and milk powder bulk D/H data show a very good differentiation from north to southernmost parts of New Zealand and a relation between rain and milk bulk D/H abundance ratio. Almost 98% of milk FAs are in the form of triglycerides that have been extracted and hydrolysed to free FAs. Free FAs were esterified and analyzed with GC-IRMS. Individual FAs show variation in D/H ratio, and all values are depleted relative to the precipitation data. The difference in D/H ratio amongst individual FAs reflects the geographical environment and biological processes i.e. micro-organisms activity in the rumen of the cow. Short chain FAs (less than 8 carbons), particularly C4 (Butyric acid), appear to be key determinants. The variation in the data can be rationalized using statistical multivariate analysis.

  10. A mitochondrial GABA permease connects the GABA shunt and the TCA cycle, and is essential for normal carbon metabolism.

    PubMed

    Michaeli, Simon; Fait, Aaron; Lagor, Kelly; Nunes-Nesi, Adriano; Grillich, Nicole; Yellin, Ayelet; Bar, Dana; Khan, Munziba; Fernie, Alisdair R; Turano, Frank J; Fromm, Hillel

    2011-08-01

    In plants, γ-aminobutyric acid (GABA) accumulates in the cytosol in response to a variety of stresses. GABA is transported into mitochondria, where it is catabolized into TCA cycle or other intermediates. Although there is circumstantial evidence for mitochondrial GABA transporters in eukaryotes, none have yet been identified. Described here is an Arabidopsis protein similar in sequence and topology to unicellular GABA transporters. The expression of this protein complements a GABA-transport-deficient yeast mutant. Thus the protein was termed AtGABP to indicate GABA-permease activity. In vivo localization of GABP fused to GFP and immunobloting of subcellular fractions demonstrate its mitochondrial localization. Direct [(3) H]GABA uptake measurements into isolated mitochondria revealed impaired uptake into mitochondria of a gabp mutant compared with wild-type (WT) mitochondria, implicating AtGABP as a major mitochondrial GABA carrier. Measurements of CO(2) release, derived from radiolabeled substrates in whole seedlings and in isolated mitochondria, demonstrate impaired GABA-derived input into the TCA cycle, and a compensatory increase in TCA cycle activity in gabp mutants. Finally, growth abnormalities of gabp mutants under limited carbon availability on artificial media, and in soil under low light intensity, combined with their metabolite profiles, suggest an important role for AtGABP in primary carbon metabolism and plant growth. Thus, AtGABP-mediated transport of GABA from the cytosol into mitochondria is important to ensure proper GABA-mediated respiration and carbon metabolism. This function is particularly essential for plant growth under conditions of limited carbon.

  11. Simultaneous inhibition of carbon and nitrogen mineralization in a forest soil by simulated acid precipitation

    SciTech Connect

    Klein, T.M.; Novick, N.J.; Kreitinger, J.P.; Alexander, M.

    1984-06-01

    One method to simulate the long-term exposure of soil to acid rain involves the addition of single doses of concentrated acid. The inhibition of carbon mineralization accompanied by a stimulation of nitrogen mineralization may result from this severe, unnatural treatment. The present study was designed to determine whether the inhibition of carbon mineralization and the accompanying enhanced nitrogen mineralization would occur when soils are treated with more dilute acid for long periods of time, as takes place in nature.

  12. The ecological effect of acid conditions and precipitation of hydrous metal oxides in a Rocky Mountain stream

    USGS Publications Warehouse

    McKnight, Diane M.; Feder, G.L.

    1984-01-01

    Periphyton and benthic invertebrates assemblages were studied at the confluence of two Rocky Mountain streams, Deer Creek and the Snake River near Montezuma, Colorado. Upstream from the confluence the Snake River is acidic and enriched in dissolved trace metals, while Deer Creek is a typical Rocky Mountain stream. In the Snake River, downstream from the confluence, the pH increases and hydrous metal oxides precipitate and cover the streambed. The algal and benthic invertebrate communities in the upstream reaches of the Snake River and in Deer Creek were very different. A liverwort, Scapania undulata var. undulata, was abundant in the Snake River, and although periphyton were very sparse, there were as many benthic invertebrates as in Deer Creek. Downstream from the confleunce, the precipitation of hydrous metal oxides greatly decreased the abundance of periphyton and benthic invertebrates. This study shows that in streams metal precipitates covering the streambed may have a more deleterious effect on stream communities than high metal-ion activities. ?? 1984 Dr. W. Junk Publishers.

  13. The effect of phosphoric acid concentration on the synthesis of nano-whiskers of calcium metaphosphate by chemical precipitation Method

    NASA Astrophysics Data System (ADS)

    Yao, Nengjian; Zhang, Yin; Kong, Deshuang; Zhu, Jianping; Tao, Yaqiu; Qiu, Tai

    2011-10-01

    Calcium metaphosphate (CMP) nano-whiskers were produced by a chemical precipitation method. In order to produce nano-powders, CMP was prepared by the mixing of two precursors, calcium oxide (CaO) and phosphate acid (H3PO4). Sparingly soluble chemicals, the Ca/P ratio of the mixture was set to be 0.50 to produce stoichiometric CMP, were chemical agitated in phosphate acid solution. At least 3 hours of pre-hydrolysis of phosphorus precursor were required to obtain CMP phase. The CMP powders were dried in a drying oven at 60 °C for 7 days and then followed by a heat treatment at 390 °C for 8hours. The obtained powder was analyzed using XRD, XRF, FT-IR, SEM, TG-DTA, Zeta Potential Meter, Specific Surface Area, and Particle Size Analyzer. The results showed that obtained CMP nano-whiskers have a significantly powder characteristics.

  14. Index markers of chronic fatigue syndrome with dysfunction of TCA and urea cycles

    PubMed Central

    Yamano, Emi; Sugimoto, Masahiro; Hirayama, Akiyoshi; Kume, Satoshi; Yamato, Masanori; Jin, Guanghua; Tajima, Seiki; Goda, Nobuhito; Iwai, Kazuhiro; Fukuda, Sanae; Yamaguti, Kouzi; Kuratsune, Hirohiko; Soga, Tomoyoshi; Watanabe, Yasuyoshi; Kataoka, Yosky

    2016-01-01

    Chronic fatigue syndrome (CFS) is a persistent and unexplained pathological state characterized by exertional and severely debilitating fatigue, with/without infectious or neuropsychiatric symptoms, lasting at least 6 consecutive months. Its pathogenesis remains incompletely understood. Here, we performed comprehensive metabolomic analyses of 133 plasma samples obtained from CFS patients and healthy controls to establish an objective diagnosis of CFS. CFS patients exhibited significant differences in intermediate metabolite concentrations in the tricarboxylic acid (TCA) and urea cycles. The combination of ornithine/citrulline and pyruvate/isocitrate ratios discriminated CFS patients from healthy controls, yielding area under the receiver operating characteristic curve values of 0.801 (95% confidential interval [CI]: 0.711–0.890, P < 0.0001) and 0.750 (95% CI: 0.584–0.916, P = 0.0069) for training (n = 93) and validation (n = 40) datasets, respectively. These findings provide compelling evidence that a clinical diagnostic tool could be developed for CFS based on the ratios of metabolites in plasma. PMID:27725700

  15. Effects of simulated acid precipitation on decomposition and leaching of organic carbon in forest soils

    SciTech Connect

    Chang, F.H.; Alexander, M.

    1984-09-01

    Soil samples from three watersheds of New York State were treated with simulated rain at pH 3.5, 4.1, and 5.6 daily for 14 d, at 12 3-d intervals in three separate tests, or at 22 7-d intervals. Except for one system of treating the three forest soils, simulated acid rain reduced the amount of organic matter leached from samples of soil from which more than 0.05% of the organic carbon was leached during the exposure period. In the soil samples representing the exceptions, acid rain enhanced the leaching of organic matter. Samples from the organic layer of the treated samples of acid soil were taken at two equal depths, and the rates of organic matter decomposition in the two layers were studied. As compared with simulated rain at pH 5.6, simulated acid rain reduced the decomposition of organic matter in the three soils at both depths in three of the five tests and at both depths of two of the soils in the fourth test. In some instances, organic matter decomposition was enhanced by the simulated acid rain. Except for the sample of soil at the highest initial pH, carbon mineralization was inhibited in soils and treatments in which simulated acid rain reduced the amount of organic carbon leached, and it was stimulated in soils and treatments in which the quantity of organic carbon leached was increased by the simulated acid rain. 12 references, 3 figures, 8 tables.

  16. Changes in acid precipitation-related water chemistry of lakes from southwestern New Brunswick, Canada, 1986-2001.

    PubMed

    Pilgrim, W; Clair, T A; Choate, J; Hughes, R

    2003-01-01

    Between 1986 and 2001, thirty-nine lakes in southwestern New Brunswick in Atlantic Canada were surveyed for acid precipitation-related water quality changes. Most of the study lakes are located on granite bedrock and represent the most acid sensitive lakes in the province. Between 1987 and 1992, hydrogen ion deposition to the lake study area averaged 452 eq ha(-1) yr(-1), compared to 338 eq ha(-1) yr(-1) between 1993 and 2000, a 25% reduction. The lake chemistry data were evaluated by dividing the lakes into four clusters for each survey year based on their acid neutralizing capacity. Twenty percent of the lakes (cluster IV) had an average ANC of 40 microeq L(-1) or greater and maintained an average pH of greater than 6 over the duration of the study period. A pH of 6 or greater is considered a healthy benchmark for maintaining biodiversity. The remaining 31 lakes (clusters I to III) had an average ANC of less than 40 microeq L(-1) and maintained an average pH of less than 6. Other lake chemistry changes included a general decline in lake sulphate and colour over the duration of the survey period, followed by more recent improvements in calcium ion, pH and ANC, and notably higher but declining aluminum levels in lower ANC and pH lakes. Nitrate accounted for 37% of the acid deposition to the study area, however it was not detectable in the lakes. Although acid deposition has declined and these lakes are beginning to show signs of acid recovery, 80% of the study lakes remain acid sensitive having little buffering capacity with low calcium, pH and ANC.

  17. The Variations of Glycolysis and TCA Cycle Intermediate Levels Grown in Iron and Copper Mediums of Trichoderma harzianum.

    PubMed

    Tavsan, Zehra; Ayar Kayali, Hulya

    2015-05-01

    The efficiency of optimal metabolic function by microorganism depends on various parameters, especially essential metal supplementation. In the present study, the effects of iron and copper metals on metabolism were investigated by determination of glycolysis and tricarboxylic acid (TCA) cycle metabolites' levels with respect to the metal concentrations and incubation period in Trichoderma harzianum. The pyruvate and citrate levels of T. harzianum increased up to 15 mg/L of copper via redirection of carbon flux though glycolysis by suppression of pentose phosphate pathway (PPP). However, the α-ketoglutarate levels decreased at concentration higher than 5 mg/L of copper to overcome damage of oxidative stress. The fumarate levels correlated with the α-ketoglutarate levels because of substrate limitation. Besides, in T. harzianum cells grown in various concentrations of iron-containing medium, the intracellular pyruvate, citrate, and α-ketoglutarate levels showed positive correlation with iron concentration due to modifying of expression of glycolysis and TCA cycle enzymes via a mechanism involving cofactor or allosteric regulation. However, as a result of consuming of prior substrates required for fumarate production, its levels rose up to 10 mg/L. PMID:25805013

  18. The Variations of Glycolysis and TCA Cycle Intermediate Levels Grown in Iron and Copper Mediums of Trichoderma harzianum.

    PubMed

    Tavsan, Zehra; Ayar Kayali, Hulya

    2015-05-01

    The efficiency of optimal metabolic function by microorganism depends on various parameters, especially essential metal supplementation. In the present study, the effects of iron and copper metals on metabolism were investigated by determination of glycolysis and tricarboxylic acid (TCA) cycle metabolites' levels with respect to the metal concentrations and incubation period in Trichoderma harzianum. The pyruvate and citrate levels of T. harzianum increased up to 15 mg/L of copper via redirection of carbon flux though glycolysis by suppression of pentose phosphate pathway (PPP). However, the α-ketoglutarate levels decreased at concentration higher than 5 mg/L of copper to overcome damage of oxidative stress. The fumarate levels correlated with the α-ketoglutarate levels because of substrate limitation. Besides, in T. harzianum cells grown in various concentrations of iron-containing medium, the intracellular pyruvate, citrate, and α-ketoglutarate levels showed positive correlation with iron concentration due to modifying of expression of glycolysis and TCA cycle enzymes via a mechanism involving cofactor or allosteric regulation. However, as a result of consuming of prior substrates required for fumarate production, its levels rose up to 10 mg/L.

  19. Soluble species in the Arctic summer troposphere - acidic gases, aerosols, and precipitation

    SciTech Connect

    Talbot, R.W.; Vijgen, A.S.; Harriss, R.C. Old Dominion Univ., Norfolk, VA )

    1992-10-01

    The large-scale spatial distribution from 0.15-to 6 km altitude in the North American Arctic troposphere of several soluble acidic gases and major aerosol species during the summertime is reported. The distribution is found to be compositionally consistent on a large spatial scale. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases while acidic sulfate aerosols dominate the particulate phase. There appears to be a surface source of NH3 over the pack ice which may originate from decay of dead marine organisms on the ice surface, evolution from surface ocean waters in open ice leads, or release from rotting sea ice. At low altitude over the pack ice this NH34 appears to partially neutralize aerosol acidity. Over sub-Arctic tundra in southeastern Alaska, inputs of marine biogenic sulfur from the Bering Sea appear to be an important source of boundary layer aerosol SO4(2-). The rainwater acidity over the tundra is typical of remote regions. 61 refs.

  20. Soluble species in the Arctic summer troposphere - Acidic gases, aerosols, and precipitation

    NASA Technical Reports Server (NTRS)

    Talbot, R. W.; Vijgen, A. S.; Harriss, R. C.

    1992-01-01

    The large-scale spatial distribution from 0.15-to 6 km altitude in the North American Arctic troposphere of several soluble acidic gases and major aerosol species during the summertime is reported. The distribution is found to be compositionally consistent on a large spatial scale. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases while acidic sulfate aerosols dominate the particulate phase. There appears to be a surface source of NH3 over the pack ice which may originate from decay of dead marine organisms on the ice surface, evolution from surface ocean waters in open ice leads, or release from rotting sea ice. At low altitude over the pack ice this NH34 appears to partially neutralize aerosol acidity. Over sub-Arctic tundra in southeastern Alaska, inputs of marine biogenic sulfur from the Bering Sea appear to be an important source of boundary layer aerosol SO4(2-). The rainwater acidity over the tundra is typical of remote regions.

  1. The effects of a simulated acid precipitation on leaf litter quality and the growth of a detritivore in a buffered lotic system.

    PubMed

    Garden, A; Davies, R W

    1988-01-01

    The effects of a simulated acid rain on leaf litter quality and the growth of a detritivore in a buffered lotic system were investigated. Exposure of Populus balsamifera L. saplings to a simulated acid precipitation prior to leaf abscission resulted in significant decreases in foliar nitrogen content and increases in carbon: nitrogen ratios. During decomposition of the leaf litter in a buffered lotic system, microbial activity was significantly reduced. Growth of Tipula commiscibilis Diane (Diptera: Tipulidae) larvae decreased significantly when fed conditioned leaves exposed to a simulated acid precipitation prior to abscission. Reductions in detritivore growth were correlated with lower potential quality of the leaf litter resulting from increased carbon: nitrogen ratios and reduced levels of microbial activity. Thus, even in well buffered freshwater ecosystems, acid precipitation can have significant indirect effects on microbial activity and macroinvertebrate growth.

  2. The effects of a simulated acid precipitation on leaf litter quality and the growth of a detritivore in a buffered lotic system.

    PubMed

    Garden, A; Davies, R W

    1988-01-01

    The effects of a simulated acid rain on leaf litter quality and the growth of a detritivore in a buffered lotic system were investigated. Exposure of Populus balsamifera L. saplings to a simulated acid precipitation prior to leaf abscission resulted in significant decreases in foliar nitrogen content and increases in carbon: nitrogen ratios. During decomposition of the leaf litter in a buffered lotic system, microbial activity was significantly reduced. Growth of Tipula commiscibilis Diane (Diptera: Tipulidae) larvae decreased significantly when fed conditioned leaves exposed to a simulated acid precipitation prior to abscission. Reductions in detritivore growth were correlated with lower potential quality of the leaf litter resulting from increased carbon: nitrogen ratios and reduced levels of microbial activity. Thus, even in well buffered freshwater ecosystems, acid precipitation can have significant indirect effects on microbial activity and macroinvertebrate growth. PMID:15092603

  3. Generation of dose-response relationships to assess the effects of acidity in precipitation on growth and productivity of vegetation

    SciTech Connect

    Evans, L.S.

    1981-01-01

    Experiments were performed with several plant species in natural environments as well in a greenhouse and/or tissue culture facilities to establish dose-response functions of plant responses to simulated acidic rain in order to determine environmental risk assessments to ambient levels of acidic rain. Response functions of foliar injury, biomass of leaves and seed of soybean and pinto beans, root yields of radishes and garden beets, and reproduction of bracken fern are considered. The dose-response function of soybean seed yields with the hydrogen ion concentration of simulated acidic rainfalls was expressed by the equation y = 21.06-1.01 log x where y = seed yield in grams per plant and x = the hydrogen concentration if ..mu..eq l/sup -1/. The correlation coefficient of this relationship was -0.90. A similar dose-response function was generated for percent fertilization of ferns in a forest understory. When percent fertilization is plotted on logarithmic scale with hydrogen ion concentration of the simulated rain solution, the Y intercept is 51.18, slope -0.041 with a correlation coefficient of -0.98. Other dose-response functions were generated that assist in a general knowledge as to which plant species and which physiological processes are most impacted by acidic precipitation. Some responses did not produce convenient dose-response relationships. In such cases the responses may be altered by other environmental factors or there may be no differences among treatment means.

  4. Synthesis of WO{sub 3} nanoparticles by citric acid-assisted precipitation and evaluation of their photocatalytic properties

    SciTech Connect

    Sánchez-Martínez, D.; Martínez-de la Cruz, A.; López-Cuéllar, E.

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► WO{sub 3} nanoparticles were synthesized by a simple citric acid-assisted precipitation. ► WO{sub 3} photocatalyst was able to the partial mineralization of rhB, IC and MO. ► WO{sub 3} can be considered as a photocatalyst active under visible light irradiation. -- Abstract: WO{sub 3} nanoparticles were synthesized by citric acid-assisted precipitation method using a 1:1.5 molar ratio of ammonium paratungstate hydrate (H{sub 42}N{sub 10}O{sub 42}W{sub 12}·xH{sub 2}O):citric acid (C{sub 6}H{sub 8}O{sub 7}). The formation of monoclinic crystal structure of WO{sub 3} at different temperatures was confirmed by X-ray powder diffraction (XRD). The characterization of the samples synthesized was complemented by transmission electron microscopy (TEM), Brunauer–Emmitt–Teller surface area (BET) and diffuse reflectance spectroscopy (DRS). According to the thermal treatment followed during the synthesis of WO{sub 3}, the morphology of the nanoparticles formed was characterized by rectangular and ovoid shapes. The photocatalytic activity of WO{sub 3} obtained under different experimental conditions was evaluated in the degradation of rhodamine B (rhB), indigo carmine (IC), methyl orange (MO), and Congo red (CR) in aqueous solution under UV and UV–vis radiation. The highest photocatalytic activity was observed in the sample obtained by thermal treatment at 700 °C. In general, the sequence of degradation of the organic dyes was: indigo carmine (IC) > rhodamine B (rhB) > methyl orange (MO) > Congo red (CR). The mineralization degree of organic dyes by WO{sub 3} photocatalysts was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 82% (rhB), 85% (IC), 28% (MO), and 7% (CR) for 96 h of lamp irradiation.

  5. National Acid Precipitation Assessment Program (NAPAP) Interim Assessment: the causes and effects of acidic deposition. Volume 2. Emissions and control

    SciTech Connect

    Not Available

    1987-01-01

    This volume on Emissions and Controls is the second in a four-volume set which comprises the NAPAP Interim Assessment. It contains three chapters, (1) Historical Emissions, (2) Emission Control Technologies, and (3) Future Emissions. Volume III, Atmospheric Processes and Deposition, contains chapters on (4) Atmospheric Processes, and (5) Acidic Deposition and Air Quality. The last volume, entitled, Effects of Acidic Deposition, covers (6) Agricultural Crops, (7) Forests, (8) Aquatics Systems, (9) 'Materials, and (10) Human Health and Visibility. Each of these chapters describes the National Program's research orientation and major conclusions within each of the ten primary areas of substantive concern. In order to learn how these first-order conclusions relate to the issue of acidic deposition in an overall, or synoptic, sense, the reader is directed to Volume I, Executive Summary, where the conclusions from each of the ten chapters are distilled in a manner that will allow interested parties to quickly reference the status of a variety of factors that pertain to the scientific understanding of acidic deposition.

  6. National Acid Precipitation Assessment Program (NAPAP) Interim Assessment: the causes and effects of acidic deposition. Volume 3. Atmospheric processes

    SciTech Connect

    Not Available

    1987-01-01

    This volume on Atmospheric Processes and Deposition is the third in a four volume set which comprises the NAPAP Interim Assessment. It contains two chapters dealing with (4) Atmospheric Processes, and (5) Acidic Deposition and Air Quality. Volume II, Emissions and Controls, contains chapters on (1) Historical Emissions, (2) Emission Control Technologies, and (3) Future Emissions. Volume IV, Effects of Acidic Deposition, contains chapters on (6) Agricultural Crops, (7) Forests, (8) Aquatic Systems, (9) Materials, and (10) Human Health and Visibility. Each of these chapters describes the National Program's research orientation and major conclusions within each of the ten primary areas of substantive concern. In order to learn how these first-order conclusions relate to the issue of acidic deposition in an overall, or synoptic, sense the reader is directed to Volume I, Executive Summary and Major Conclusions, where the conclusions from each of the ten chapters are distilled in a manner that will allow interested parties to quickly reference the status of a variety of factors that pertain to the scientific understanding of acidic deposition.

  7. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    NASA Astrophysics Data System (ADS)

    Vet, Robert; Artz, Richard S.; Carou, Silvina

    2014-08-01

    Investigating and assessing the chemical composition of precipitation and atmospheric deposition is essential to understanding how atmospheric pollutants contribute to contemporary environmental concerns including ecosystem acidification and eutrophication, loss of biodiversity, air pollution and global climate change. Evidence of the link between atmospheric deposition and these environmental issues is well established. The state of scientific understanding of this link is that present levels of atmospheric deposition of sulfur and nitrogen adversely affect terrestrial and aquatic ecosystems, putting forest sustainability and aquatic biodiversity at risk. Nitrogen and phosphorus loadings are linked to impacts on the diversity of terrestrial and aquatic vegetation through biological cycling, and atmospheric deposition plays a major role in the emission-transport-conversion-loss cycle of chemicals in the atmosphere as well as the formation of particulate matter and ozone in the troposphere. Evidence also shows that atmospheric constituents are changing the earth's climate through direct and indirect atmospheric processes. This Special Issue, comprising a single article titled "A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus", presents a recent comprehensive review of precipitation chemistry and atmospheric deposition at global and regional scales. The information in the Special Issue, including all supporting data sets and maps, is anticipated to be of great value not only to the atmospheric deposition community but also to other science communities including those that study ecosystem impacts, human health effects, nutrient processing, climate change, global and hemispheric modeling and biogeochemical cycling. Understanding and quantifying pollutant loss from the atmosphere is, and will remain, an important component of each of these scientific fields as they

  8. Soluble species in the Arctic summer troposphere: Acidic gases, aerosols, and precipitation

    NASA Astrophysics Data System (ADS)

    Talbot, R. W.; Vijgen, A. S.; Harriss, R. C.

    1992-10-01

    We report here the distribution of selected acidic gases and aerosol species in the North American Arctic and sub-Arctic summer troposphere. The summertime troposphere is an acidic environment, with HCOOH and CH3COOH the principal acidic gases and acidic sulfate aerosols dominating the particulate phase. Our data show that the acidic gas and aerosol composition is uniform on a large spatial scale. There appears to be a surface source of NH4+ over the Arctic Ocean pack ice which may reflect release of NH3 from decay of dead marine organisms on the ice surface near ice leads, release from rotting sea ice, or an upward flux from surface ocean waters in open ice leads. This NH3 appears to partially neutralize aerosol acidity in the boundary layer. Over sub-Arctic tundra in southwestern Alaska inputs of marine biogenic sulfur from the nearby Bering Sea appear to be an important source of boundary layer aerosol SO42-. While there were only minor effects on aerosol chemistry over the tundra from sea salt, the rainwater chemistry showed influence from marine aerosols which were apparently incorporated into air masses during frontal passages moving inland from the Bering Sea. The rainwater acidity over the tundra (pH 4.69) is typical of remote regions. The principal acidity components are H2SO4 and carboxylic acids, especially HCOOH. The carboxylic acids appear to have a strong continental biogenic source, but hydrocarbons of marine origin and emissions from forest fires may also be important. The wet deposition fluxes of NO3--N and SO42--S over sub-Arctic tundra during July-August 1988 were 2.1 and 2.4 mmol m-2 yr-1. Wet deposition of NO3- was nearly 3 times higher than the average NOy deposition flux, which is believed to represent primarily dry deposition of HNO3 (Bakwin et al., this issue). Our measurements indicate that the mid-troposphere in the Arctic is generally contaminated with low levels of anthropogenic pollutants even in summer when direct atmospheric coupling

  9. Aquatic Activities for Middle School Children. A Focus on the Effects of Acid Precipitation.

    ERIC Educational Resources Information Center

    Minnesota Univ., Minneapolis. Minnesota Sea Grant Program.

    Basic water-related concepts and underlying principles of acid rain are described in this curriculum in a manner that young children can understand. The curriculum consists of activities presented in four units: Background Unit, Earth Science Unit, Life Science Unit, and Extension Unit. The first three units consist of several modules, each module…

  10. Acid precipitation effects on algal productivity and biomass in Adirondack Mountain lakes

    SciTech Connect

    Hendrey, G.R.

    1982-12-01

    Relationships between phytoplankton communities and lake acidity in three Adirondack Mountain lakes were studied at Woods Lake (pH ca. 4.9), Sagamore Lake (pH ca. 5.5), and Panther Lake (pH ca. 7.0). Species numbers decrease with increasing acidity. Patterns of increasing biomass and productivity in Woods Lake may be atypical of similar oligotrophic lakes in that they develop rather slowly to maxima six weeks after ice-out, instead of occurring very close to ice-out. Contributions of netplankton, nannoplankton and ultraplankton to productivity per m/sup 2/ show that the smaller plankton are relatively more important in the more acid lakes. This pattern could be determined by nutrient availability (lake acidification is suspected of leading to decreased availability of phosphorus). This was consistent with a hypothesis that microbial heterotrophic activity is reduced with increasing acidity, but the smaller phytoplankton may be more leaky at low pH. 11 references, 2 tables.

  11. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer

    NASA Astrophysics Data System (ADS)

    Cánovas, C. R.; Macías, F.; Pérez-López, R.

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40 days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  12. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer.

    PubMed

    Cánovas, C R; Macías, F; Pérez-López, R

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  13. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer.

    PubMed

    Cánovas, C R; Macías, F; Pérez-López, R

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  14. Preparing Poly (Lactic-co-Glycolic Acid) (PLGA) Microspheres Containing Lysozyme-Zinc Precipitate Using a Modified Double Emulsion Method

    PubMed Central

    Nafissi Varcheh, Nastaran; Luginbuehl, Vera; Aboofazeli, Reza; Peter Merkle, Hans

    2011-01-01

    Lysozyme, as a model protein, was precipitated through the formation of protein-Zn complex to micronize for subsequent encapsulation within poly (lactic-co-glycolic acid) (PLGA) microspheres. Various parameters, including pH, type and concentration of added salts and protein concentration, were modified to optimize the yield of protein complexation and precipitation. The resulting protein particles (lysozyme-Zn complex as a freshly prepared suspension or a freeze-dried solid) were then loaded into PLGA (Resomer® 503H) microspheres, using a double emulsion technique and microspheres encapsulation efficiency and their sizes were determined. It was observed that salt type could significantly influence the magnitude of protein complexation. At the same conditions, zinc chloride was found to be more successful in producing pelletizable lysozyme. Generally, higher concentrations of protein solution led also to the higher yields of complexation and at the optimum conditions, the percentage of pelletizable lysozyme reached to 80%. Taking advantage of this procedure, a modified technique for preparation of protein-loaded PLGA microspheres was established, although it is also expected that this technique increases the protein drugs stabilization during the encapsulation process. PMID:24250344

  15. Production and characterization of poly(3-hydroxybutyrate) generated by Alcaligenes latus using lactose and whey after acid protein precipitation process.

    PubMed

    Berwig, Karina Hammel; Baldasso, Camila; Dettmer, Aline

    2016-10-01

    Whey after acid protein precipitation was used as substrate for PHB production in orbital shaker using Alcaligenes latus. Statistical analysis determined the most appropriate hydroxide for pH neutralization of whey after protein precipitation among NH4OH, KOH and NaOH 10%w/v. The results were compared to those of commercial lactose. A scale-up test in a 4L bioreactor was done at 35°C, 750rpm, 7L/min air flow, and 6.5 pH. The PHB was characterized through Fourier Transform Infrared Spectroscopy, thermogravimetry and differential scanning calorimetry. NH4OH provided the best results for productivity (p), 0.11g/L.h, and for polymer yield, (YP/S), 1.08g/g. The bioreactor experiment resulted in lower p and YP/S. PHB showed maximum degradation temperature (291°C), melting temperature (169°C), and chemical properties similar to those of standard PHB. The use of whey as a substrate for PHB production did not affect significantly the final product quality. PMID:27347795

  16. Electrostatic precipitation of condensed acid mist: First quarterly technical progress report, September 1 to November 30, 1988

    SciTech Connect

    Dahlin, R.S.

    1988-01-01

    This report covers the project scope and structure for developing and demonstrating a compact, wet electrostatic collector for condensed acid mist in power plant flue gas. In order to accomplish this goal, the objectives to be met are: (1) a laboratory-version of the WESP (Wet Electrostatic Precipitator) must be fabricated. (2) the WESP performance must be optimized through laboratory tests with a nonvolatile simulant aerosol having a size distribution similar to the acid mist. (3) the WESP concept must be proven by demonstrating adequate collection of actual acid mist in a pilot coal combustion facility under conditions simulating a full-scale power plant burning high-sulfur coal. (4) a computer model of the WESP process must be developed to assist in the process optimization, interpretation of test results, and extrapolation to full scale. (5) Utility participation must be solicited in a follow-on demonstration of the WESP concept at a full-scale power plant. 5 refs., 2 figs. (JL)

  17. Electrostatic precipitation of condensed acid mist: Second quarterly technical progress report, December 1, 1988--February 28, 1989

    SciTech Connect

    Dahlin, R.S.

    1989-01-01

    This report covers the project scope and structure for developing and demonstrating a compact, wet electrostatic collector for condensed acid mist in power plant flue gas. In order to accomplish this goal, the objectives to be met are: (1) a laboratory-version of the WESP (Wet Electrostatic Precipitator) must be fabricated, (2) the WESP performance must be optimized through laboratory tests with a nonvolatile simulant aerosol having a size distribution similar to the acid mist, (3) the WESP concept must be proven by demonstrating adequate collection of actual acid mist in a pilot coal combustion facility under conditions simulating a full-scale power plant burning high-sulfur coal, (4) a computer model of the WESP process must be developed to assist in the process optimization, interpretation of test results, and extrapolation to full scale, and (5) utility participation must be solicited in a follow-on demonstration of the WESP concept at a full-scale power plant. Progress in laboratory testing and collection efficiency is described. 5 refs., 2 figs.

  18. Ammonia emission factors for the NAPAP (National Acid Precipitation Assessment Program) emission inventory. Final report, January 1985-December 1986

    SciTech Connect

    Misenheimer, D.C.; Warn, T.E.; Zelmanowitz, S.

    1987-01-01

    The report provides information on certain sources of ammonia emissions to the atmosphere for use in the National Acid Precipitation Assessment Program (NAPAP) emission inventories. Major anthropogenic sources of ammonia emissions to the atmosphere are identified, and emission factors for these sources are presented based on a review of the most recent data available. The emission factors developed are used to estimate nationwide emissions for base year 1980 and are compared to ammonia emission factors used in other emission inventories. Major anthropogenic source categories covered are cropland spreading of livestock wastes, beef cattle feedlots, fertilizer manufacture and use, fuel combustion, ammonia synthesis, petroleum refineries, and coke manufacture. Approximately 840,000 tons of ammonia is estimated to have been emitted in the U.S. in 1980; over 64% of which is estimated to have been from livestock wastes.

  19. The Tribolium castaneum cell line TcA: a new tool kit for cell biology.

    PubMed

    Silver, Kristopher; Jiang, Hongbo; Fu, Jinping; Phillips, Thomas W; Beeman, Richard W; Park, Yoonseong

    2014-10-30

    The red flour beetle, Tribolium castaneum, is an agriculturally important insect pest that has been widely used as a model organism. Recently, an adherent cell line (BCIRL-TcA-CLG1 or TcA) was developed from late pupae of the red flour beetle. Next generation transcriptome sequencing of TcA cells demonstrated expression of a wide variety of genes associated with specialized functions in chitin metabolism, immune responses and cellular and systemic RNAi pathways. Accordingly, we evaluated the sensitivity of TcA cells to dsRNA to initiate an RNAi response. TcA cells were highly sensitive to minute amounts of dsRNA, with a minimum effective dose of 100 pg/mL resulting in significant suppression of gene expression. We have also developed a plasmid containing two TcA-specific promoters, the promoter from the 40S ribosomal protein subunit (TC006550) and a bi-directional heat shock promoter (TcHS70) from the intergenic space between heat shock proteins 68a and b. These promoters have been employed to provide high levels of either constitutive (TC006550) or inducible (TcHS70) gene expression of the reporter proteins. Our results show that the TcA cell line, with its sensitivity to RNAi and functional TcA-specific promoters, is an invaluable resource for studying basic molecular and physiological questions.

  20. Trans fatty acids in diets act as a precipitating factor for gut inflammation?

    PubMed

    Okada, Yoshikiyo; Tsuzuki, Yoshikazu; Ueda, Toshihide; Hozumi, Hideaki; Sato, Shingo; Hokari, Ryota; Kurihara, Chie; Watanabe, Chikako; Tomita, Kengo; Komoto, Shunsuke; Kawaguchi, Atsushi; Nagao, Shigeaki; Miura, Soichiro

    2013-12-01

    Fatty acids in our daily diet are broadly classified into cis and trans fatty acids (TFAs). TFAs are formed during the manufacturing process of hydrogenated vegetable oils such as margarine. Modern diets such as deep-fried products, frozen foods, and packaged snacks commonly include large quantities of margarine containing TFAs. Although an increased report in the effects of the diet containing TFAs on a risk factor of metabolic syndrome, diabetes mellitus, and coronary heart disease has been observed in the recent years, influence on intestinal inflammation remains unknown. This review describes pro-inflammatory effects of TFAs in our diary diet on various systemic disorders and also discusses a possible role of TFAs on gut inflammation. PMID:24251700

  1. Red spruce germination and growth in soil-mediated regeneration microcosms under acid precipitation

    SciTech Connect

    Ho, M.

    1992-01-01

    In the past three decades, atmospheric pollution has caused substantial problems for the environment as well as for many biological processes. The objective of this study focuses on red spruce (Picea ruben Sarg.) regeneration potential and chemical change within the soil-water-plant continuum following simulated acid rain treatments. Inceptisols from three forests at 1735, 1920, and 2015 m at Mt. Mitchell, North Carolina had lower pH, bulk density, and higher organic matter, and base cations as altitude increased. Red spruce seeds were collected from two nearby standing trees at the 1735 m site. A strip-split-split plot experiment was constructed using soils from the two lower elevations, which support natural red spruce stands. Besides a control (pH 5.6, NO[sub 3]:SO[sub 4] ratio 0.10), eight treatments corresponding to two pHs (3.5 and 4.2) with four NO[sub 3]:SO[sub 4] ratios (0.20, 0.33, 0.40, and 0.67) each were used. Seedling emergence and growth, chemistry of soil. Soil leachate, and plant tissue were analyzed to test soil differences and treatment effects of acidity, nitrate, and sulfate. Temporal patterns of germination respond more to soil than to rain chemistry, but significant interactions were found. Besides higher survival, faster germinating seedlings in the 1735 m soil also produced more complex root system and more biomass. Lower root-to-shoot ratios at more acidic treatments suggest a negative effect of acidity on root growth. Canonical discriminant analysis revealed that factors controlling overall soil chemistry were dominated by soil origin, then by rain pH.

  2. The effect of random precipitation times on the scavenging rate for tropospheric nitric acid

    NASA Technical Reports Server (NTRS)

    Stewart, Richard W.

    1988-01-01

    A model for the effective scavenging rate of a soluble species has been developed. The model takes into account the possibility of positive as well as negative correlations between departures from the mean of the scavenging rate and species concentration. The model is demonstrated for the case of late afternoon rainout of nitric acid occurring just prior to the nighttime cessation of its chemical production. The calculations give effective scavenging rates which are about a factor of 2 to 3 greater than those calculated using the models of Rodhe and Grandell (1972) and Giorgi and Chameides (1985).

  3. Acidity, nutrients, and minerals in atmospheric precipitation over Florida: deposition patterns, mechanisms and ecological effects

    SciTech Connect

    Brezonik, P.L.; Hendry, C.D. Jr.; Edgerton, E.S.; Schulze, R.L.; Crisman, T.L.

    1983-06-01

    A monitoring network of 21 bulk and 4 wet/dry collectors located throughout Florida measured spatial and temporal trends during a one-year period from May 1978 to April 1979. The project summary notes that statewide deposition rates of nitrogen and phosphorus were below the loading rates associated with eutrophication, although nutrient concentrations were higher during the summer. Overall, pH appears to have relatively small effects (in the range 4.7-6.8) on community structure in soft-water Florida lakes. More dramatic effects could occur under more acidic conditions in the future. 4 references, 5 figures, 1 table.

  4. Detection of chlorodifluoroacetic acid in precipitation: A possible product of fluorocarbon degradation

    SciTech Connect

    Martin, J.W.; Franklin, J.; Hanson, M.L.; Solomon, K.R.; Mabury, S.A.; Ellis, D.A.; Scott, B.F.; Muri, D.C.G.

    2000-01-15

    Chlorodiffluoroacetic acid (CDFA) was detected in rain and snow samples from various regions of Canada. Routine quantitative analysis was performed using an in-situ derivatization technique that allowed for the determination of CDFA by GC-MS of the anilide derivative. Validation of environmental CDFA was provided by strong anionic exchange chromatography and detection by {sup 19}F NMR. CDFA concentrations ranges from <7.1 to 170 ng L{sup {minus}1} among all samples analyzed. Monthly volume-weighted CDFA concentrations ranged from <7.1 to 170 ng L{sup {minus}1} among all samples analyzed. Monthly volume-weighted CDFA concentrations in rain event samples showed a seasonal trend between June and November 1998, peaking in late summer and decreasing in the fall for Guelph and Toronto sites. Preliminary toxicity tests with the aquatic macrophytes Myriophyllum sibiricum and Myriophyllum spicatum suggest that CDFA does not represent a risk of acute toxicity to these aquatic macrophytes at current environmental concentrations. A degradation study suggests that CDFA is recalcitrant to biotic and abiotic degradation relative to dichloroacetic acid (DCA) and may accumulate in the aquatic environment. On the basis of existing experimental data, the authors postulate that CDFA is a degradation product of CFC-113 and, to a lesser extent, HCFC-142b. If CFC-113 is a source, its ozone depletion potential may be lower than previously assumed. Further work is required to identify alternative atmospheric and terrestrial sources of CDFA.

  5. Reconstitution of TCA cycle with DAOCS to engineer Escherichia coli into an efficient whole cell catalyst of penicillin G.

    PubMed

    Lin, Baixue; Fan, Keqiang; Zhao, Jian; Ji, Junjie; Wu, Linjun; Yang, Keqian; Tao, Yong

    2015-08-11

    Many medically useful semisynthetic cephalosporins are derived from 7-aminodeacetoxycephalosporanic acid (7-ADCA), which has been traditionally made by the polluting chemical method. Here, a whole-cell biocatalytic process based on an engineered Escherichia coli strain expressing 2-oxoglutarate-dependent deacetoxycephalosporin C synthase (DAOCS) for converting penicillin G to G-7-ADCA is developed. The major engineering strategy is to reconstitute the tricarboxylic acid (TCA) cycle of E. coli to force the metabolic flux to go through DAOCS catalyzed reaction for 2-oxoglutarate to succinate conversion. Then the glyoxylate bypass was disrupted to eliminate metabolic flux that may circumvent the reconstituted TCA cycle. Additional engineering steps were taken to reduce the degradation of penicillin G and G-7-ADCA in the bioconversion process. These steps include engineering strategies to reduce acetate accumulation in the biocatalytic process and to knock out a host β-lactamase involved in the degradation of penicillin G and G-7-ADCA. By combining these manipulations in an engineered strain, the yield of G-7-ADCA was increased from 2.50 ± 0.79 mM (0.89 ± 0.28 g/L, 0.07 ± 0.02 g/gDCW) to 29.01 ± 1.27 mM (10.31 ± 0.46 g/L, 0.77 ± 0.03 g/gDCW) with a conversion rate of 29.01 mol%, representing an 11-fold increase compared with the starting strain (2.50 mol%).

  6. Citric acid cycle and role of its intermediates in metabolism.

    PubMed

    Akram, Muhammad

    2014-04-01

    The citric acid cycle is the final common oxidative pathway for carbohydrates, fats and amino acids. It is the most important metabolic pathway for the energy supply to the body. TCA is the most important central pathway connecting almost all the individual metabolic pathways. In this review article, introduction, regulation and energetics of TCA cycle have been discussed. The present study was carried out to review literature on TCA cycle.

  7. Adsorption compared with sulfide precipitation as metal removal processes from acid mine drainage in a constructed wetland

    NASA Astrophysics Data System (ADS)

    Machemer, Steven D.; Wildeman, Thomas R.

    1992-01-01

    Metal removal processes from acid mine drainage were studied in an experimental constructed wetland in the Idaho Springs-Central City mining district of Colorado. The wetland was designed to passively remove heavy metals from the mine drainage flowing from the Big Five Tunnel. Concurrent studies were performed in the field on the waters flowing from the wetland and in the laboratory on the wetland substrate. Both studies suggest that there is competition for organic adsorption sites among Fe, Cu, Zn and Mn. Iron and Cu appear to be more strongly adsorbed than Zn and Mn. The adsorption of metals varies with the fluctuation of pH in the outflow water. Also indicated by field and laboratory studies is the microbial reduction of sulfate with a corresponding increase in the sulfide concentration of the water. As sulfide is generated. Cu and Zn are completely removed. The field results suggest that upon start up of a constructed wetland, the adsorption of dissolved metals onto organic sites in the substrate material will be an important process. Over time, sulfide precipitation becomes the dominant process for metal removal from acid mine drainage.

  8. Biomass and production of amphipods in low alkalinity lakes affected by acid precipitation.

    PubMed

    France, R L

    1996-01-01

    Population biomass and production of the amphipod Hyalella azteca (Saussure) were found to be related to alkalinity (ranging from 0.2 to 58.1 mg liter(-1)) in 10 Canadian Shield lakes in south-central Ontario. Biomass and production of amphipods in the two lakes characterized by spring depressions of pH below 5.0 were found to be lower than those for populations inhabiting lakes that did not experience such acid pulses. The proportional biomass of amphipods in relation to the total littoral zoobenthos community was lower in lakes of low alkalinity than in circumneutral or hardwater lakes. Because production in these amphipod populations is known to depend closely on population abundance, the labour-intensive derivation of production rates yields relatively little information for biomonitoring that cannot be obtained from abundance data alone. PMID:15093505

  9. Biomass and production of amphipods in low alkalinity lakes affected by acid precipitation.

    PubMed

    France, R L

    1996-01-01

    Population biomass and production of the amphipod Hyalella azteca (Saussure) were found to be related to alkalinity (ranging from 0.2 to 58.1 mg liter(-1)) in 10 Canadian Shield lakes in south-central Ontario. Biomass and production of amphipods in the two lakes characterized by spring depressions of pH below 5.0 were found to be lower than those for populations inhabiting lakes that did not experience such acid pulses. The proportional biomass of amphipods in relation to the total littoral zoobenthos community was lower in lakes of low alkalinity than in circumneutral or hardwater lakes. Because production in these amphipod populations is known to depend closely on population abundance, the labour-intensive derivation of production rates yields relatively little information for biomonitoring that cannot be obtained from abundance data alone.

  10. Evaluation of a commercial AdvancedTCA board management controller solution (IPMC)

    NASA Astrophysics Data System (ADS)

    Mendez, J.; Bobillier, V.; Haas, S.; Joos, M.; Vasey, F.

    2016-02-01

    The MicroTCA (MTCA) and AdvancedTCA (ATCA) industry standards have been selected as the hardware platform for the upgrade of the electronic systems of some of the experiments at the Large Hadron Collider (LHC) . In this context, the electronics support group for experiments at CERN is running a project to perform technical evaluations of MTCA and ATCA equipment. As part of this activity, a commercial solution for an Intelligent Platform Management Controller (IPMC), an essential component of any ATCA blade design, is being evaluated. We validated the supported IPMC features, checked the interoperability and adapted the reference design for use on an existing ATCA carrier board.

  11. Jarosite Precipitation from Acidic Saline Waters in Kachchh, Gujarat, India: an Appropriate Martian Analogue?

    NASA Astrophysics Data System (ADS)

    Mitra, S.; Gupta, S.; Bhattacharya, S.; Banerjee, S.; Chauhan, P.; Parthasarathy, G.

    2014-12-01

    The origin of jarosite [KFe3(SO4)2(OH)6] on the Martian surface has been an intriguing problem since the Mars Exploration Rover 'Opportunity' first revealed its presence at the Meridiani Planum on Mars. To explain its origin, several terrestrial analogue sites have been studied in different geographical zones. Although several models have been suggested, there is a consensus that only the prevalence of acidic and oxidizing aqueous environmental conditions are conducive to form jarosite. In the Kachchh region of Gujarat, western India, jarosite has been recently discovered from gorges dissecting the Paleocene Matanumadh Formation sediments, that overlie basalts of the Deccan Volcanic Province. This formation comprises pebble conglomerates, carbonaceous shales and purple sandstones capped by a laterite on top. Jarosite, in association with gypsum and goethite, has been detected through FTIR and VNIR spectrometry in almost all litho-units of the succession, albeit in different modes and concentrations. The occurrence of jarosite within black shale in other parts of the world, has been attributed to the oxidation of pyrites within the shale layers. However, in shales of the Matanumadh Formation, jarosite is restricted to fractures that cut across the bedding, while the overlying purple sandstone unit only preserves jarosite in shale clasts within the sandstone. Since the sandstone overlies the black shale layer, downward percolation of sulfate-bearing water from the oxidation of pyrite within the shale layer cannot explain jarosite formation in this unit. In addition, no jarosite is observed below or within pyrite-rich lignite bearing sections in other parts of Kachchh. Alternative suggestions, that jarosite developed in the immediate aftermath of Deccan volcanism as surface waters were rendered acidic by interaction with the final phase of volcanic effusives, are also unlikely as on-going studies suggest that jarosite is not restricted to the Matanumadh Formation. The

  12. Limestone characterization to model damage from acidic precipitation: Effect of pore structure on mass transfer

    USGS Publications Warehouse

    Leith, S.D.; Reddy, M.M.; Irez, W.F.; Heymans, M.J.

    1996-01-01

    The pore structure of Salem limestone is investigated, and conclusions regarding the effect of the pore geometry on modeling moisture and contaminant transport are discussed based on thin section petrography, scanning electron microscopy, mercury intrusion porosimetry, and nitrogen adsorption analyses. These investigations are compared to and shown to compliment permeability and capillary pressure measurements for this common building stone. Salem limestone exhibits a bimodal pore size distribution in which the larger pores provide routes for convective mass transfer of contaminants into the material and the smaller pores lead to high surface area adsorption and reaction sites. Relative permeability and capillary pressure measurements of the air/water system indicate that Salem limestone exhibits high capillarity end low effective permeability to water. Based on stone characterization, aqueous diffusion and convection are believed to be the primary transport mechanisms for pollutants in this stone. The extent of contaminant accumulation in the stone depends on the mechanism of partitioning between the aqueous and solid phases. The described characterization techniques and modeling approach can be applied to many systems of interest such as acidic damage to limestone, mass transfer of contaminants in concrete and other porous building materials, and modeling pollutant transport in subsurface moisture zones.

  13. The antioxidant role of Sideritis caesarea infusion against TCA toxicity in rats.

    PubMed

    Celik, Ismail; Kaya, Mehmet Salih

    2011-03-01

    Sideritis caesarea (SC) Duman, Aytac & Baser is a member of the Lamiaceae family. The present study was designed to investigate the antioxidant properties of the aerial parts of island green tea SC against TCA effects in rats. Biomarkers selected for monitoring antioxidant capacity were the activities of glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase, catalase (CAT), GSH level and malondialdehyde (MDA) content in various organs of rats. Three experimental groups, A (untreated = control), B (only TCA-treated) and C (TCA+SC-treated), were studied. At the end of the 50 d experiment, the MDA content in tissues increased significantly in group B, whereas no significant changes were observed in group C as compared with that of the control group. Antioxidant enzyme activities such as SOD and CAT increased significantly in the brain, liver and kidneys of group B but decreased significantly in group C as compared with group B. The GSH level and GR activity increased significantly in the brain and liver of group C as compared with the control and TCA-exposed rats. Hence, the study reveals that the constituents present in SC impart protection against chemical-induced oxidative injury that may result in the development of cancer. PMID:21078212

  14. PICMG xTCA Standards Extensions for Physics: New Developments & Future Plans

    SciTech Connect

    Larsen, R.S.; /SLAC

    2010-08-26

    After several years of planning and workshop meetings, a decision was reached in late 2008 to organize PICMG xTCA for Physics Technical Subcommittees to extend the ATCA and MTCA telecom standards for enhanced system performance, availability and interoperability for physics controls and applications hardware and software. Since formation in May-June 2009, the Hardware Technical Subcommittee has developed a number of ATCA, ARTM, AMC, MTCA and RTM extensions to be completed in mid-to-late 2010. The Software Technical Subcommittee is developing guidelines to promote interoperability of modules designed by industry and laboratories, in particular focusing on middleware and generic application interfaces such as Standard Process Model, Standard Device Model and Standard Hardware API. The paper describes the prototype design work completed by the lab-industry partners to date, the timeline for hardware releases to PICMG for approval, and the status of the software guidelines roadmap. The paper also briefly summarizes the program of the 4th xTCA for Physics Workshop immediately preceding the RT2010 Conference. he case for developing ATCA and MicroTCA (xTCA) specification extensions for physics has been covered in several previous papers. Briefly, ATCA and MicroTCA is the first all-serial communication platform available to the physics community to support both massively complex accelerator controls and massively large, high bandwidth and throughput experimental data acquisition systems. The major strength of xTCA is its multi-layer highly scalable managed platform architecture designed to achieve the highest possible system availability. Physics research imaging technologies have driven industrial applications in a wide range of medical scanners, for example, and in turn continue to evolve to exponentially higher speeds and resolution through new computer, communications industry and analog-to-digital conversion chip developments. The high availability managed platform is

  15. LC-MSMS identification of Arabidopsis thaliana heat-stable seed proteins: enriching for LEA-type proteins by acid treatment.

    PubMed

    Oliveira, E; Amara, I; Bellido, D; Odena, M A; Domínguez, E; Pagès, M; Goday, A

    2007-11-01

    Protein identification in systems containing very highly abundant proteins is not always efficient and usually requires previous enrichment or fractionation steps in order to uncover minor proteins. In plant seeds, identification of late embryogenesis abundant (LEA) proteins is often masked by the presence of the large family of storage proteins. LEA-proteins are predicted to play a role in plant stress tolerance. They are highly hydrophilic proteins, generally heat-stable, and correlate with dehydration in seeds or vegetative tissues. In the present work, we analyze the protein composition of heat-stable Arabidopsis thaliana seed extracts after treatment with trichloroacetic acid (TCA). The composition of the proteins that precipitate and those that remain in solution in 3% TCA was analyzed by two different approaches: 1D SDS-PAGE coupled to LC-ESI-MSMS analysis and a gel-free protocol associated with LC-MALDI-MSMS. Our results indicate that treating total heat-soluble extracts with 3% TCA is an effective procedure to remove storage proteins by selective precipitation and this fractionation step provides a soluble fraction highly enriched in Lea-type proteins. The analysis and determination of protein identities in this acid-soluble fraction by MS technology is a suitable system for large-scale identification of Lea-proteins present in seeds.

  16. [A preliminary study on the chemical properties of precipitation, throughfall, stemflow and surface run-off in major forest types at Dinghushan under acid deposition].

    PubMed

    Liu, Juxiu; Zhang, Deqiang; Zhou, Guoyi; Wen, Dazhi; Zhang, Qianmei

    2003-08-01

    Studies on the chemical properties of precipitation, throughfall, stemflow and surface run-off in major forest types at Dinghushan under acid deposition showed that the pH value of precipitation was about 4.90, and the frequency of acid rain was over 62%. In broad-leaved forest, the pH value of precipitation was lower than that of throughfall, but higher than that of stemflow and especially the surface run-off, indicating that the soil was naturally acidified. In mixed forest, both throughfall and surface run-off had a higher pH value, but stemflow had a lower pH value than precipitation. The throughfall and stemflow were more acidified than precipitation in coniferous pine forest, but the surface run-off had a higher pH value than precipitation. These results suggested that among the three major forest types at Dinghushan, the canopy of broad-leaved forest had the highest buffering ability, whereas for the soil, the coniferous forest had the highest soil buffering capacity. The concentrations of nutrient elements, such as P, K, Ca, Na and Mg in the throughfall, stemflow and surface run-off were higher than those in bulk precipitation in all forests at Dinghushan, some even 10 times higher, indicating that a large amount of nutrients were leached from the canopy. The concentrations of nutrient elements in stemflow were higher than those in throughfall in all forests, and the concentration of nutrient elements in surface water was higher than those in atmospheric rainfall. Coniferous forest had a higher concentration of nutrients in the throughfall and stemflow and a lower nutrient concentration in the surface run-off than other forest types, which implied that nutrient loss was more serious in broad-leaved and mixed forests than in coniferous forests.

  17. Decolorization of acid and basic dyes: understanding the metabolic degradation and cell-induced adsorption/precipitation by Escherichia coli.

    PubMed

    Cerboneschi, Matteo; Corsi, Massimo; Bianchini, Roberto; Bonanni, Marco; Tegli, Stefania

    2015-10-01

    Escherichia coli strain DH5α was successfully employed in the decolorization of commercial anthraquinone and azo dyes, belonging to the general classes of acid or basic dyes. The bacteria showed an aptitude to survive at different pH values on any dye solution tested, and a rapid decolorization was obtained under aerobic conditions for the whole collection of dyes. A deep investigation about the mode of action of E. coli was carried out to demonstrate that dye decolorization mainly occurred via three different pathways, specifically bacterial induced precipitation, cell wall adsorption, and metabolism, whose weight was correlated with the chemical nature of the dye. In the case of basic azo dyes, an unexpected fast decolorization was observed after just 2-h postinoculation under aerobic conditions, suggesting that metabolism was the main mechanism involved in basic azo dye degradation, as unequivocally demonstrated by mass spectrometric analysis. The reductive cleavage of the azo group by E. coli on basic azo dyes was also further demonstrated by the inhibition of decolorization occurring when glucose was added to the dye solution. Moreover, no residual toxicity was found in the E. coli-treated basic azo dye solutions by performing Daphnia magna acute toxicity assays. The results of the present study demonstrated that E. coli can be simply exploited for its natural metabolic pathways, without applying any recombinant technology. The high versatility and adaptability of this bacterium could encourage its involvement in industrial bioremediation of textile and leather dyeing wastewaters.

  18. Use of a non-linear model in examining growth responses of loblolly pine to ozone and acid precipitation

    NASA Astrophysics Data System (ADS)

    Somerville, Matthew C.; Shadwick, Douglas S.; Meldahl, Ralph S.; Chappelka, Arthur H.; Lockaby, B. Graeme

    Monthly diameter 2 × height ( d 2h ) data were measured over two years in open-top chambers at Auburn University, Alabama. This study exposed seedlings from two half-sibling loblolly pine ( Pinus taeda L.) families to ozone and acid precipitation treatments. For these data, the accumulation of d 2h ) by individual trees over two years was efficiently represented by a six-parameter non-linear model of ln ( d 2h ) as a function of time. Multivariate analysis of variance using these six estimated parameters for each seedling resulted in greater sensitivity to treatment differences as measured by tests of hypotheses than did analysis of covariance on ln (final d 2h ). This result illustrates the importance of utilizing appropriate analyses that can bring as much of the data as is possible to bear on the question at hand. A test for additional information indicated that five of the six parameters contributed important information concerning treatment differences for at least one of the two families tested. It may be inferred that the treatments have an important effect on the nature of d 2h accumulation within a growing season as well as on the d 2h at the end of the growing season.

  19. Biologically-induced precipitation of sphalerite-wurtzite nanoparticles by sulfate-reducing bacteria: implications for acid mine drainage treatment.

    PubMed

    Castillo, Julio; Pérez-López, Rafael; Caraballo, Manuel A; Nieto, José M; Martins, Mónica; Costa, M Clara; Olías, Manuel; Cerón, Juan C; Tucoulou, Rémi

    2012-04-15

    Several experiments were conducted to evaluate zinc-tolerance of sulfate-reducing bacteria (SRB) obtained from three environmental samples, two inocula from sulfide-mining districts and another inoculum from a wastewater treatment plant. The populations of SRB resisted zinc concentrations of 260 mg/L for 42 days in a sulfate-rich medium. During the experiments, sulfate was reduced to sulfide and concentrations in solution decreased. Zinc concentrations also decreased from 260 mg/L to values below detection limit. Both decreases were consistent with the precipitation of newly-formed sphalerite and wurtzite, two polymorphs of ZnS, forming <2.5-μm-diameter spherical aggregates identified by microscopy and synchrotron-μ-XRD. Sulfate and zinc are present in high concentrations in acid mine drainage (AMD) even after passive treatments based on limestone dissolution. The implementation of a SRB-based zinc removal step in these systems could completely reduce the mobility of all metals, which would improve the quality of stream sediments, water and soils in AMD-affected landscapes.

  20. Zirconium(IV) tungstate nanoparticles prepared through chemical co-precipitation method and its function as solid acid catalyst

    NASA Astrophysics Data System (ADS)

    Sadanandan, Manoj; Bhaskaran, Beena

    2014-08-01

    In this paper, we report the synthesis of zirconium(IV) tungstate nanoparticles, a new and efficient catalyst for the oxidation of benzyl alcohol and esterification of acetic acid with various alcohols. The nanoparticle catalyst was prepared using the room temperature chemical co-precipitation method. The catalyst was characterized with thermogravimetric and differential thermal analysis, elemental analysis, X-ray diffraction analysis (XRD), fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM) and the Brunauer-Emmett-Teller (BET) surface area. The crystallite size was found to be ~20 nm as revealed by XRD, HRTEM and AFM. The Na+ exchange capacity was found to be 2.76 meq g-1 and the surface area of the compound measured using BET method was found to be 250-265 m2 g-1. The high value of ion exchange capacity indicates the presence of surface hydroxyl groups. The prepared nanoparticles have proven to be excellent catalysts for both oxidation and ester synthesis under mild reaction conditions. The mechanism of the catalytic reaction was studied as well.

  1. The effects of acid precipitation runoff episodes on reservoir and tapwater quality in an Appalachian Mountain water supply.

    PubMed Central

    Sharpe, W E; DeWalle, D R

    1990-01-01

    The aluminum concentration and Ryznar Index increased and the pH decreased in a small Appalachian water supply reservoir following acid precipitation runoff episodes. Concomitant increases in tapwater aluminum and decreases in tapwater pH were also observed at two homes in the water distribution system. Lead concentrations in the tapwater of one home frequently exceeded recommended levels, although spatial and temporal variation in tapwater copper and lead concentrations was considerable. Since source water and reservoir water copper and lead concentrations were much lower, the increased copper and lead concentrations in tapwater were attributed to corrosion of household plumbing. Tapwater copper concentration correlated well with tapwater pH and tapwater temperature. Asbestos fibers were not detected in tapwater. The asbestos-cement pipe in the water distribution system was protected by a spontaneous metallic coating that inhibited fiber release from the pipe. Several simultaneous reactions were hypothesized to be taking place in the distribution system that involved corrosion of metallic components and coating of asbestos-cement pipe components in part with corrosion products and in part by cations of watershed origin. Greater water quality changes might be expected in areas of higher atmospheric deposition. Images FIGURE 5. FIGURE 6. PMID:2088742

  2. The effects of acid precipitation runoff episodes on reservoir and tapwater quality in an Appalachian Mountain water supply

    SciTech Connect

    Sharpe, W.E.; DeWalle, D.R. )

    1990-11-01

    The aluminum concentration and Ryznar Index increased and the pH decreased in a small Appalachian water supply reservoir following acid precipitation runoff episodes. Concomitant increases in tapwater aluminum and decreases in tapwater pH were also observed at two homes in the water distribution system. Lead concentrations in the tapwater of one home frequently exceeded recommended levels, although spatial and temporal variation in tapwater copper and lead concentrations was considerable. Since source water and reservoir water copper and lead concentrations were much lower, the increased copper and lead concentrations in tapwater were attributed to corrosion of household plumbing. Tapwater copper concentration correlated well with tapwater pH and tapwater temperature. Asbestos fibers were not detected in tapwater. The asbestos-cement pipe in the water distribution system was protected by a spontaneous metallic coating that inhibited fiber release from the pipe. Several simultaneous reactions were hypothesized to be taking place in the distribution system that involved corrosion of metallic components and coating of asbestos-cement pipe components in part with corrosion products and in part by cations of watershed origin. Greater water quality changes might be expected in areas of higher atmospheric deposition.

  3. Susceptibility to acidic precipitation contributes to the decline of the terricolous lichens Cetraria aculeata and Cetraria islandica in central Europe.

    PubMed

    Hauck, Markus

    2008-04-01

    The effective quantum yield of photochemical energy conversion in photosystem II (Phi2) was shown to be reduced in the terricolous lichens Cetraria aculeata and Cetraria islandica by short-term exposure to aqueous SO2 at pH values occurring in the precipitation of areas with high SO2 pollution. Significant reduction of Phi2 was found at pHacid, a major lichen substance of C. islandica, increases the pollution tolerance in lichens.

  4. The effects of acid precipitation runoff episodes on reservoir and tapwater quality in an Appalachian Mountain water supply.

    PubMed

    Sharpe, W E; DeWalle, D R

    1990-11-01

    The aluminum concentration and Ryznar Index increased and the pH decreased in a small Appalachian water supply reservoir following acid precipitation runoff episodes. Concomitant increases in tapwater aluminum and decreases in tapwater pH were also observed at two homes in the water distribution system. Lead concentrations in the tapwater of one home frequently exceeded recommended levels, although spatial and temporal variation in tapwater copper and lead concentrations was considerable. Since source water and reservoir water copper and lead concentrations were much lower, the increased copper and lead concentrations in tapwater were attributed to corrosion of household plumbing. Tapwater copper concentration correlated well with tapwater pH and tapwater temperature. Asbestos fibers were not detected in tapwater. The asbestos-cement pipe in the water distribution system was protected by a spontaneous metallic coating that inhibited fiber release from the pipe. Several simultaneous reactions were hypothesized to be taking place in the distribution system that involved corrosion of metallic components and coating of asbestos-cement pipe components in part with corrosion products and in part by cations of watershed origin. Greater water quality changes might be expected in areas of higher atmospheric deposition.

  5. Biologically-induced precipitation of sphalerite-wurtzite nanoparticles by sulfate-reducing bacteria: implications for acid mine drainage treatment.

    PubMed

    Castillo, Julio; Pérez-López, Rafael; Caraballo, Manuel A; Nieto, José M; Martins, Mónica; Costa, M Clara; Olías, Manuel; Cerón, Juan C; Tucoulou, Rémi

    2012-04-15

    Several experiments were conducted to evaluate zinc-tolerance of sulfate-reducing bacteria (SRB) obtained from three environmental samples, two inocula from sulfide-mining districts and another inoculum from a wastewater treatment plant. The populations of SRB resisted zinc concentrations of 260 mg/L for 42 days in a sulfate-rich medium. During the experiments, sulfate was reduced to sulfide and concentrations in solution decreased. Zinc concentrations also decreased from 260 mg/L to values below detection limit. Both decreases were consistent with the precipitation of newly-formed sphalerite and wurtzite, two polymorphs of ZnS, forming <2.5-μm-diameter spherical aggregates identified by microscopy and synchrotron-μ-XRD. Sulfate and zinc are present in high concentrations in acid mine drainage (AMD) even after passive treatments based on limestone dissolution. The implementation of a SRB-based zinc removal step in these systems could completely reduce the mobility of all metals, which would improve the quality of stream sediments, water and soils in AMD-affected landscapes. PMID:22414495

  6. Response of surface water chemistry to reduced levels of acid precipitation: comparison of trends in two regions of New York, USA

    NASA Astrophysics Data System (ADS)

    Burns, Douglas A.; McHale, Michael R.; Driscoll, Charles T.; Roy, Karen M.

    2006-04-01

    In light of recent reductions in sulphur (S) and nitrogen (N) emissions mandated by Title IV of the Clean Air Act Amendments of 1990, temporal trends and trend coherence in precipitation (1984-2001 and 1992-2001) and surface water chemistry (1992-2001) were determined in two of the most acid-sensitive regions of North America, i.e. the Catskill and Adirondack Mountains of New York. Precipitation chemistry data from six sites located near these regions showed decreasing sulphate (SO42-), nitrate (NO3-), and base cation (CB) concentrations and increasing pH during 1984-2001, but few significant trends during 1992-2001. Data from five Catskill streams and 12 Adirondack lakes showed decreasing trends in SO42- concentrations at all sites, and decreasing trends in NO3-, CB, and H+ concentrations and increasing trends in dissolved organic carbon at most sites. In contrast, acid-neutralizing capacity (ANC) increased significantly at only about half the Adirondack lakes and in one of the Catskill streams. Flow correction prior to trend analysis did not change any trend directions and had little effect on SO42- trends, but it caused several significant non-flow-corrected trends in NO3- and ANC to become non-significant, suggesting that trend results for flow-sensitive constituents are affected by flow-related climate variation. SO42- concentrations showed high temporal coherence in precipitation, surface waters, and in precipitation-surface water comparisons, reflecting a strong link between S emissions, precipitation SO42- concentrations, and the processes that affect S cycling within these regions. NO3- and H+ concentrations and ANC generally showed weak coherence, especially in surface waters and in precipitation-surface water comparisons, indicating that variation in local-scale processes driven by factors such as climate are affecting trends in acid-base chemistry in these two regions.

  7. Response of surface water chemistry to reduced levels of acid precipitation: Comparison of trends in two regions of New York, USA

    USGS Publications Warehouse

    Burns, Douglas A.; McHale, M.R.; Driscoll, C.T.; Roy, K.M.

    2006-01-01

    In light of recent reductions in sulphur (S) and nitrogen (N) emissions mandated by Title IV of the Clean Air Act Amendments of 1990, temporal trends and trend coherence in precipitation (1984-2001 and 1992-2001) and surface water chemistry (1992-2001) were determined in two of the most acid-sensitive regions of North America, i.e. the Catskill and Adirondack Mountains of New York. Precipitation chemistry data from six sites located near these regions showed decreasing sulphate (SO42-), nitrate (NO3-), and base cation (CB) concentrations and increasing pH during 1984-2001, but few significant trends during 1992-2001. Data from five Catskill streams and 12 Adirondack lakes showed decreasing trends in SO42- concentrations at all sites, and decreasing trends in NO3-, CB, and H+ concentrations and increasing trends in dissolved organic carbon at most sites. In contrast, acid-neutralizing capacity (ANC increased significantly at only about half the Adirondack lakes and in one of the Catskill streams. Flow correction prior to trend analysis did not change any trend directions and had little effect on SO42- trends, but it caused several significant non-flow-corrected trends in NO3- and ANC to become non-significant, suggesting that trend results for flow-sensitive constituents are affected by flow-related climate variation. SO42- concentrations showed high temporal coherence in precipitation, surface waters, and in precipitation-surface water comparisons, reflecting a strong link between S emissions, precipitation SO42- concentrations, and the processes that affect S cycling within these regions. NO3- and H+ concentrations and ANC generally showed weak coherence, especially in surface waters and in precipitation-surface water comparisons, indicating that variation in local-scale processes driven by factors such as climate are affecting trends in acid-base chemistry in these two regions. Copyright ?? 2005 John Wiley & Sons, Ltd.

  8. Rocks, soils, and water quality. Relationships and implications for effects of acid precipitation on surface water in the northeastern United States

    SciTech Connect

    Kaplan, E.; Thode, H.C. Jr.; Protas, A.

    1981-05-01

    Distribution of rocks and soils in Northeast counties were investigated for the degree to which they influence pH and alkalinity in surface waters. Using 283 counties, path analysis resulted in two models of equivalent explanatory power. Each model indicated the importance of both rocks and soils as determinants of pH and alkalinity in surface waters, and as important factors in the sensitivity of natural waters to acidification from acid precipitation. Previous studies have emphasized the importance of bedrock geology, at the expense of knowledge about soils, in an understanding of waters sensitive to the effects of acid precipitation. Our regional analysis found that rocks were contributors to the buffering capacity of surface water; however, the presence of a large percentage of alfisol soils better indicates locations of waters with higher levels of alkalinity, and thus of greater resistance to effects of acid rain.

  9. Selective Precipitation of Thorium lodate from a Tartaric Acid-Hydrogen Peroxide Medium Application to Rapid Spectrophotometric Determination of Thorium in Silicate Rocks and in Ores

    USGS Publications Warehouse

    Grimaldi, F.S.

    1957-01-01

    This paper presents a selective iodate separation of thorium from nitric acid medium containing d-tartaric acid and hydrogen peroxide. The catalytic decomposition of hydrogen peroxide is prevented by the use of 8quinolinol. A few micrograms of thorium are separated sufficiently clean from 30 mg. of such oxides as cerium, zirconium, titanium, niobium, tantalum, scandium, or iron with one iodate precipitation to allow an accurate determination of thorium with the thoronmesotartaric acid spectrophotometric method. The method is successful for the determination of 0.001% or more of thorium dioxide in silicate rocks and for 0.01% or more in black sand, monazite, thorite, thorianite, eschynite, euxenite, and zircon.

  10. Partitioning and inactivation of viruses by the caprylic acid precipitation followed by a terminal pasteurization in the manufacturing process of horse immunoglobulins.

    PubMed

    Mpandi, M; Schmutz, P; Legrand, E; Duc, R; Geinoz, J; Henzelin-Nkubana, C; Giorgia, S; Clerc, O; Genoud, D; Weber, T

    2007-10-01

    Caprylic acid (octanoic acid), has been used for over 50 years as a stabilizer of human albumin during pasteurization. In addition caprylic acid is of great interest, by providing the advantage of purifying mammalian immunoglobulins and clearing viruses infectivity in a single step. Exploiting these two properties, we sequentially used the caprylic acid precipitation and the pasteurization to purify horse hyperimmune globulins used in the manufacturing of Sérocytol. To evaluate the effectiveness of the process for the removal/inactivation of viruses, spiking studies were carried out for each dedicated step. Bovine viral diarrhoea virus (BVDV), pseudorabies virus (PRV), encephalomyocarditis virus (EMCV) and minute virus of mice (MVM) were used for the virological validation. Our data show that the treatment with caprylic acid 5% (v/v) can effectively be used as well to purify or to ensure viral safety of immunoglobulins. Caprylic acid precipitation was very efficient in removing and/or inactivating enveloped viruses (PRV, BVDV) and moderately efficient against non-enveloped viruses (MVM, ECMV). However the combination with the pasteurization ensured an efficient protection against both enveloped and non-enveloped viruses. So that viruses surviving to the caprylic acid precipitation will be neutralized by pasteurization. Significant log reduction were achieved > or =9 log(10) for enveloped viruses and 4 log(10) for non-enveloped viruses, providing the evidence of a margin of viral safety achieved by our manufacturing process. Its a simple and non-expensive manufacturing process of immunoglobulins easily validated that we have adapted to a large production scale with a programmable operating system.

  11. Trichloroacetic acid

    Integrated Risk Information System (IRIS)

    Trichloroacetic acid ( TCA ) ; CASRN 76 - 03 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Nonca

  12. National Acid Precipitation Assessment Program (NAPAP) Interim Assessment: the causes and effects of acidic deposition. Volume 4. Effects of acidic deposition

    SciTech Connect

    Not Available

    1987-01-01

    This volume on Effects of Acidic Deposition is the last in a four-volume set which comprises the NAPAP Interim Assessment. It contains five individual chapters covering (6) Agricultural Crops, (7) Forests, (8) Aquatic Systems, (9) Materials, and (10) Human Health and Visibility. Volume III, Atmospheric Processes and Deposition, has two chapters on (4) Atmospheric Processes, and (5) Acidic Deposition and Air Quality. Volume II, Emissions and Controls, contains three chapters on (1) Historical Emissions, (2) Emission Control Technologies, and (3) Future Emissions. Each of these chapters describes the National Program's research orientation and major conclusions within each of the ten primary areas of substantive concern. In order to learn how these first-order conclusions relate to the issue of acidic deposition in an overall, or synoptic, sense, the reader is directed to Volume I, Executive Summary, where the conclusions from each of the ten subject chapters are distilled in a manner that will allow interested parties to quickly reference the status of a variety of factors that pertain to the scientific understanding of acidic deposition.

  13. PRECIPITATION OF PROTACTINIUM

    DOEpatents

    Moore, R.L.

    1958-07-15

    An lmprovement in the separation of protactinium from aqueous nitric acid solutions is described. 1t covers the use of lead dioxide and tin dioxide as carrier precipitates for the protactinium. In carrying out the process, divalent lead or divalent tin is addcd to the solution and oxidized, causing formation of a carrier precipitate of lead dioxide or stannic oxide, respectively.

  14. Partial reverse of the TCA cycle is enhanced in Taenia crassiceps experimental neurocysticercosis after in vivo treatment with anthelminthic drugs.

    PubMed

    de Almeida Leandro, Leticia; Fraga, Carolina Miguel; de Souza Lino, Ruy; Vinaud, Marina Clare

    2014-04-01

    Neurocysticercosis (NCC) is the most common helminthic infection and neglected disease of the central nervous system. It is the leading cause of acquired epilepsy and seizures worldwide. Therefore, to study this important neglected disease, it is important to use experimental models. There is no report in the literature on how the parasite's metabolism reacts to antihelminthic treatment when it is still within the central nervous system of the host. Therefore, the aim of this study was to investigate the energetic metabolism of cysticerci experimentally inoculated in the encephala of BALB/c mice after treatment with low dosages (not sufficient to kill the parasite) of albendazole (ABDZ) and praziquantel (PZQ). BALB/c mice were intracranially inoculated with Taenia crassiceps cysticerci and, after 30 days, received treatment with low dosages of ABDZ and PZQ. After 24 h of treatment, the mice were euthanized, and the cysticerci were removed and analyzed through high-performance liquid chromatography (HPLC) to quantify the organic acids related to the energetic metabolism of the parasite. The partial reverse of the TCA cycle was enhanced by the ABDZ and PZQ treatments both with the higher dosage, as the organic acids of this pathway were significantly increased when compared to the control group and to the other dosages. In conclusion, it was possible to detect the increase of this pathway in the parasites that were exposed to low dosages of ABDZ and PZQ, as it is a mechanism that would amplify the energy production in a hostile environment.

  15. Treatment technologies and mechanisms for three odorants at trace level: IPMP, IBMP, and TCA.

    PubMed

    Li, Xin; Lin, Pengfei; Wang, Jun; Liu, Yuanyuan; Li, Yong; Zhang, Xiaojian; Chen, Chao

    2016-01-01

    Odour episodes caused by algal metabolites are gaining more and more attention in recent years. Besides geosmin and 2-methylisoborneol (MIB), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), and 2,4,6-trichloroanisole (TCA) have emerged to be important off-flavour sources. Their low odour threshold concentrations (several ng ·L(-1)), which are even lower than those of MIB and geosmin, pose challenges for treatment strategies. Hence, a practical and efficient mitigation technology is needed. The possible practical technologies, including powdered activated carbon (PAC) adsorption and oxidation by chlorine and potassium permanganate, were investigated. The results indicated that chlorine and potassium permanganate oxidation of the three odorants were unfeasible while PAC adsorption was effective. As for adsorption, TCA, followed by IBMP and IPMP, was most easily removed by PAC. The Freundlich model could well describe the adsorption isotherm data. The adsorption capacities for IPMP, IBMP, and TCA were described as follows: [Formula: see text], [Formula: see text], and [Formula: see text]. For five earthy/musty odorants including geosmin and MIB, octanol/water partition coefficient, molecular weight, and polarizability all promoted adsorption while aqueous solubility showed a negative influence. The hydrophobic interaction was believed to be the dominant force in the adsorption mechanism while the π-electron interaction enhanced adsorption when a benzene ring was present. This result could be used to predict the adsorption performance of emerging odorants. PMID:26150209

  16. Effects of acidic precipitation on the water quality of streams in the Laurel Hill area, Somerset County, Pennsylvania, 1983-86

    USGS Publications Warehouse

    Barker, J.L.; Witt, E. C.

    1990-01-01

    Five headwater streams in the Laurel Hill area in southwestern Pennsylvania were investigated from September 1983 through February 1986 to determine possible effects of acidic precipitation on water quality. Precipitation in the Laurel Hill area is among the most acidic in the Nation, with a mean volume-weighted pH of 4.06. Sulfate is the dominant acid-forming anion, averaging 3.6 milligrams per liter or about 50 kilograms per hectare in wet deposition alone. Nitrate averages about 2 milligrams per liter or 7 kilograms per hectare in the study area. Stream chemistry in the five streams is quite variable and apparently is influenced to a large degree by the bedrock geology and by small amounts of alkaline material in watershed soils. Three of the five streams with no or little acid-neutralizing capacity presently are devoid of fish because of low pH and elevated aluminum concentrations. Aluminum concentrations increase in the other two streams during rainfall and snowmelt despite comparatively higher base flow and acid-neutralizing capacities. Comparison of the chemistry of streamflow during 14 storm events at South Fork Bens Creek and North Fork Bens Creek reveals similar chemical responses when discharge suddenly increases. Concentrations of dissolved metals and sulfate increased during stormflow and snowmelt runoff, whereas concentrations of base cations, silica, and chloride decreased. Nitrate concentrations were not affected by rainfall runoff by tended to increase with snowmelt runoff.

  17. Effects of acidic precipitation on the water quality of streams in the Larel Hill area, Somerset County, Pennsylvania, 1983-86

    SciTech Connect

    Barker, J.L.; Witt, E.C.

    1990-01-01

    Five headwater streams in the Laurel Hill area in southwestern Pennsylvania were investigated from September 1983 through February 1986 to determine possible effects of acidic precipitation on water quality. Precipitation in the Larel Hill area is among the most acidic in the Nation, with a mean volume-weighted pH of 4.06. Sulfate is the dominant acid-forming anion, averaging 3.6 mg/L or about 50 kg/hectare in wet deposition alone. Nitrate averages about 2 mg/L or 7 kg/hectare in the study area. Stream chemistry in the five streams is quite variable and apparently is influenced to a large degree by the bedrock geology and by small amounts of alkaline material in watershed soils. Three of the five streams with no or little acid-neutralizing capacity present are devoid of fish because of low pH and elevated aluminum concentrations. Aluminum concentrations increase in the other two streams during rainfall and snowmelt despite comparatively higher base flow and acid-neutralizing capacities. Comparison of the chemistry of streamflow during 14 storm events at South Fork Bens Creek and North Bens creek reveals similar chemical responses when discharge suddenly increases. concentrations of dissolved metals and sulfate increased during stormflow and snowmelt runoff, whereas concentrations of base cations, silica, and chloride decreased. Nitrate concentrations were not affected by rainfall runoff, but tended to increase with snowmelt runoff. 36 refs., 19 figs., 15 tabs.

  18. Synthesis of aqueous suspensions of magnetic nanoparticles with the co-precipitation of iron ions in the presence of aspartic acid

    NASA Astrophysics Data System (ADS)

    Pušnik, Klementina; Goršak, Tanja; Drofenik, Miha; Makovec, Darko

    2016-09-01

    There is increasing demand for the production of large quantities of aqueous suspensions of magnetic iron-oxide nanoparticles. Amino acids are one possible type of inexpensive, nontoxic, and biocompatible molecules that can be used as the surfactants for the preparation of stable suspensions. This preparation can be conducted in a simple, one-step process based on the co-precipitation of Fe3+/Fe2+ ions in the presence of the amino acid. However, the presence of this amino acid changes the mechanism of the magnetic nanoparticles' formation. In this investigation we analyzed the influence of aspartic amino acid (Asp) on the formation of magnetic iron-oxide nanoparticles during the co-precipitation. The process of the nanoparticles' formation was followed using a combination of TEM, x-ray diffractometry, magnetic measurements, in-situ FT-IR spectroscopy, and chemical analysis, and compared with the formation of nanoparticles without the Asp. The Asp forms a coordination complex with the Fe3+ ions, which impedes the formation of the intermediate iron oxyhydroxide phase and suppresses the growth of the final magnetic iron-oxide nanoparticles. Slower reaction kinetics can lead to the formation of nonmagnetic secondary phases. The aspartic-acid-absorbed nanoparticles can be dispersed to form relatively concentrated aqueous suspensions displaying a good colloidal stability at an increased pH.

  19. A perspective of stepwise utilisation of Bayer red mud: Step two--Extracting and recovering Ti from Ti-enriched tailing with acid leaching and precipitate flotation.

    PubMed

    Huang, Yanfang; Chai, Wencui; Han, Guihong; Wang, Wenjuan; Yang, Shuzhen; Liu, Jiongtian

    2016-04-15

    The extraction and recovery of Ti from Ti-enriched tailing with acid leaching and precipitate flotation, as one of the critical steps, was proposed for the stepwise utilization of red mud. The factors influencing acid leaching and precipitate flotation were examined by factorial design. The leaching thermodynamics, kinetics of Ti(4+), Al(3+) and Fe(3+), and the mechanism of selectively Fe(3+) removal using [Hbet][Tf2N] as precipitating reagent were discussed. The extracting of Ti(4+), Al(3+) and Fe(3+) in concentrated H2SO4 is controlled by diffusion reactions, depending mainly upon leaching time and temperature. The maximum extracting efficiency of Ti(4+) is approximately 92.3%, whereas Al(3+) and Fe(3+) leaching are respectively 75.8% and 84.2%. [Hbet][Tf2N], as a precipitating reagent, operates through a coordination mechanism in flotation. The pH value is the key factor influencing the flotation recovery of Ti(4+), whereas the dosage of precipitating reagent is that for Al(3+) recovery. The maximum flotation recovery of Ti(4+) is 92.7%, whereas the maximum Al(3+) recovery is 93.5%. The total recovery rate for extracting and recovering titanium is 85.5%. The liquor with Ti(4+) of 15.5g/L, Al(3+) of 30.4g/L and Fe(3+) of 0.48g/L was obtained for the following hydrolysis step in the integrated process for red mud utilisation. PMID:26799223

  20. Caprylic acid-induced impurity precipitation from protein A capture column elution pool to enable a two-chromatography-step process for monoclonal antibody purification.

    PubMed

    Zheng, Ji; Wang, Lu; Twarowska, Barbara; Laino, Sarah; Sparks, Colleen; Smith, Timothy; Russell, Reb; Wang, Michelle

    2015-01-01

    This article presents the use of caprylic acid (CA) to precipitate impurities from the protein A capture column elution pool for the purification of monoclonal antibodies (mAbs) with the objective of developing a two chromatography step antibody purification process. A CA-induced impurity precipitation in the protein A column elution pool was evaluated as an alternative method to polishing chromatography techniques for use in the purification of mAbs. Parameters including pH, CA concentrations, mixing time, mAb concentrations, buffer systems, and incubation temperatures were evaluated on their impacts on the impurity removal, high-molecular weight (HMW) formation and precipitation step yield. Both pH and CA concentration, but not mAb concentrations and buffer systems, are key parameters that can affect host-cell proteins (HCPs) clearance, HMW species, and yield. CA precipitation removes HCPs and some HMW species to the acceptable levels under the optimal conditions. The CA precipitation process is robust at 15-25°C. For all five mAbs tested in this study, the optimal CA concentration range is 0.5-1.0%, while the pH range is from 5.0 to 6.0. A purification process using two chromatography steps (protein A capture column and ion exchange polishing column) in combination with CA-based impurity precipitation step can be used as a robust downstream process for mAb molecules with a broad range of isoelectric points. Residual CA can be effectively removed by the subsequent polishing cation exchange chromatography.

  1. Dwell Time and Surface Parameter Effects on Removal of Silicone Oil From D6ac Steel Using TCA

    NASA Technical Reports Server (NTRS)

    Boothe, R. E.

    2003-01-01

    This study was conducted to evaluate the impact of dwell time, surface roughness, and the surface activation state on 1,1,1-trichloroethane's (TCA's) effectiveness for removing silicone oil from D6ac steel. Silicone-contaminated test articles were washed with TCA solvent, and then the surfaces were analyzed for residue, using Fourier transform infrared spectroscopy. The predominant factor affecting the ability to remove the silicone oil was surface roughness.

  2. Tricarboxylic Acid Cycle-Dependent Attenuation of Staphylococcus aureus In Vivo Virulence by Selective Inhibition of Amino Acid Transport▿

    PubMed Central

    Zhu, Yefei; Xiong, Yan Q.; Sadykov, Marat R.; Fey, Paul D.; Lei, Mei G.; Lee, Chia Y.; Bayer, Arnold S.; Somerville, Greg A.

    2009-01-01

    Staphylococci are the leading causes of endovascular infections worldwide. Commonly, these infections involve the formation of biofilms on the surface of biomaterials. Biofilms are a complex aggregation of bacteria commonly encapsulated by an adhesive exopolysaccharide matrix. In staphylococci, this exopolysaccharide matrix is composed of polysaccharide intercellular adhesin (PIA). PIA is synthesized when the tricarboxylic acid (TCA) cycle is repressed. The inverse correlation between PIA synthesis and TCA cycle activity led us to hypothesize that increasing TCA cycle activity would decrease PIA synthesis and biofilm formation and reduce virulence in a rabbit catheter-induced model of biofilm infection. TCA cycle activity can be induced by preventing staphylococci from exogenously acquiring a TCA cycle-derived amino acid necessary for growth. To determine if TCA cycle induction would decrease PIA synthesis in Staphylococcus aureus, the glutamine permease gene (glnP) was inactivated and TCA cycle activity, PIA accumulation, biofilm forming ability, and virulence in an experimental catheter-induced endovascular biofilm (endocarditis) model were determined. Inactivation of this major glutamine transporter increased TCA cycle activity, transiently decreased PIA synthesis, and significantly reduced in vivo virulence in the endocarditis model in terms of achievable bacterial densities in biofilm-associated cardiac vegetations, kidneys, and spleen. These data confirm the close linkage of TCA cycle activity and virulence factor production and establish that this metabolic linkage can be manipulated to alter infectious outcomes. PMID:19667045

  3. A modified method for the detection of microbial proteases on agar plates using tannic acid.

    PubMed

    Saran, Saurabh; Isar, Jasmine; Saxena, Rajendra Kumar

    2007-06-10

    In routine assay for the screening of microbes producing proteases, 10% trichloroaceticacid (TCA) is flooded on the milk agar plates after inoculation and required incubation to precipitate the protein. However, the clarity of the hydrolyzed zone is not very sharp and distinct. We herein present an improved assay for detecting the presence of extracellular protease from microorganisms on agar plates. In this method 10% tannic acid is flooded on the milk agar plate (in place of, TCA) to observe the zone of hydrolysis. Tannic acid sharply increases the colour intensity of the plate, as it favours the precipitation of the unhydrolyzed protein in the plate, thereby improving the contrast between the intact zones and the enzymatic lyses zones of the substrate. Our results indicate that this method is useful to detect extracellular proteases produced by both fungi as well as bacteria. The method used in the present study is sensitive, and can be easily performed for screening of large number of microbial cultures. This is the first report on the use of tannic acid for the detection of microbial proteases.

  4. Modeling Precipitation and Sorption of Al, U and Co-contaminants during Titration of Acidic Sediments in Recirculation Flow-Through Experiments

    SciTech Connect

    Tang, Guoping; Luo, Wensui; Brooks, Scott C; Watson, David B; Gu, Baohua

    2013-01-01

    We conducted batch and recirculating column titration tests with contaminated acidic sediments with controlled CO2 in the headspace, and extended the geochemical model by Gu et al. (2003, GCA) to better understand and quantify the reactions governing trace metal fate in the subsurface. The sediment titration curve showed slow pH increase due to strong buffering by Al precipitation and CO2 uptake. Assuming precipitation of basaluminite at low saturation index (SI=-4), and decreasing cation exchange selectivity coefficient (kNa\\Al=0.3), the predictions are close to the observed pH and Al; and the model explains 1) the observed Ca, Mg, and Mn concentration decrease by cation exchange with sorbed Al, and 2) the decrease of U by surface complexation with Fe hydroxides at low pH, and precipitation as liebigite (Ca2UO2(CO3)3:10H2O) at pH>5.5. Without further adjustment geochemical parameters, the model describes reasonably well previous sediment and column titration tests without CO2 in the headspace, as well as the new large column test. The apparent inhibition of U and Ni decrease in the large column can be explained by formation of aqueous carbonate complexes and/or competition with carbonate for surface sites. These results indicated that ignoring labile solid phase Al would underestimate base requirement in titration of acidic aquifers.

  5. Mitochondria-Translocated PGK1 Functions as a Protein Kinase to Coordinate Glycolysis and the TCA Cycle in Tumorigenesis.

    PubMed

    Li, Xinjian; Jiang, Yuhui; Meisenhelder, Jill; Yang, Weiwei; Hawke, David H; Zheng, Yanhua; Xia, Yan; Aldape, Kenneth; He, Jie; Hunter, Tony; Wang, Liwei; Lu, Zhimin

    2016-03-01

    It is unclear how the Warburg effect that exemplifies enhanced glycolysis in the cytosol is coordinated with suppressed mitochondrial pyruvate metabolism. We demonstrate here that hypoxia, EGFR activation, and expression of K-Ras G12V and B-Raf V600E induce mitochondrial translocation of phosphoglycerate kinase 1 (PGK1); this is mediated by ERK-dependent PGK1 S203 phosphorylation and subsequent PIN1-mediated cis-trans isomerization. Mitochondrial PGK1 acts as a protein kinase to phosphorylate pyruvate dehydrogenase kinase 1 (PDHK1) at T338, which activates PDHK1 to phosphorylate and inhibit the pyruvate dehydrogenase (PDH) complex. This reduces mitochondrial pyruvate utilization, suppresses reactive oxygen species production, increases lactate production, and promotes brain tumorigenesis. Furthermore, PGK1 S203 and PDHK1 T338 phosphorylation levels correlate with PDH S293 inactivating phosphorylation levels and poor prognosis in glioblastoma patients. This work highlights that PGK1 acts as a protein kinase in coordinating glycolysis and the tricarboxylic acid (TCA) cycle, which is instrumental in cancer metabolism and tumorigenesis.

  6. Preparation of ellagic acid molecularly imprinted polymeric microspheres based on distillation-precipitation polymerization for the efficient purification of a crude extract.

    PubMed

    Zhang, Hua; Zhao, Shangge; Zhang, Lu; Han, Bo; Yao, Xincheng; Chen, Wen; Hu, Yanli

    2016-08-01

    Molecularly imprinted polymeric microspheres with a high recognition ability toward the template molecule, ellagic acid, were synthesized based on distillation-precipitation polymerization. The as-obtained polymers were characterized by scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. Static, dynamic, and selective binding tests were adopted to study the binding properties and the molecular recognition ability of the prepared polymers for ellagic acid. The results indicated that the maximum static adsorption capacity of the prepared polymers toward ellagic acid was 37.07 mg/g and the adsorption equilibrium time was about 100 min when the concentration of ellagic acid was 40 mg/mL. Molecularly imprinted polymeric microspheres were also highly selective toward ellagic acid compared with its analogue quercetin. It was found that the content of ellagic acid in the pomegranate peel extract was enhanced from 23 to 86% after such molecularly imprinted solid-phase extraction process. This work provides an efficient way for effective separation and enrichment of ellagic acid from complex matrix, which is especially valuable in industrial production. PMID:27311588

  7. Preparation of ellagic acid molecularly imprinted polymeric microspheres based on distillation-precipitation polymerization for the efficient purification of a crude extract.

    PubMed

    Zhang, Hua; Zhao, Shangge; Zhang, Lu; Han, Bo; Yao, Xincheng; Chen, Wen; Hu, Yanli

    2016-08-01

    Molecularly imprinted polymeric microspheres with a high recognition ability toward the template molecule, ellagic acid, were synthesized based on distillation-precipitation polymerization. The as-obtained polymers were characterized by scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. Static, dynamic, and selective binding tests were adopted to study the binding properties and the molecular recognition ability of the prepared polymers for ellagic acid. The results indicated that the maximum static adsorption capacity of the prepared polymers toward ellagic acid was 37.07 mg/g and the adsorption equilibrium time was about 100 min when the concentration of ellagic acid was 40 mg/mL. Molecularly imprinted polymeric microspheres were also highly selective toward ellagic acid compared with its analogue quercetin. It was found that the content of ellagic acid in the pomegranate peel extract was enhanced from 23 to 86% after such molecularly imprinted solid-phase extraction process. This work provides an efficient way for effective separation and enrichment of ellagic acid from complex matrix, which is especially valuable in industrial production.

  8. Acidification of soil-water in low base-saturated sand soils of the superior uplands under acid and normal precipitation.

    PubMed

    Harris, A R

    1989-04-01

    Lakes and streams are acidified by direct precipitation and water channeled through nearby soils, but water in low base-saturation soils can produce highly acidic percolate after prolonged contact and subsequent degassing in surface waters. Theories advanced by Reuss (1983), Reuss and Johnson (1985), and Seip and Rustad (1984) suggest that soils with less than 15% base saturation are susceptible to soil-water pH depression of up to 0.4 unit, which is sufficient to cause negative alkalinity in soil solutions. High concentrations of mobile anions (notably sulfate) are responsible for the negative alkalinity and these solutions on CO2 degassing in surface waters can retain acidities equivalent to a pH value of 5.0 or less. This mechanism purports to explain why some lakes acidify when they are surrounded by acid soils and cation leaching is not required.Ambient precipitation set to pH 5.4 and pH 4.2 was applied to columns of low base-saturated, sand, soils, starting in 1985. The columns (15 cm diameter and 150 cm long) were collected from soils with base saturations falling into one of three groups (0-10, 10-20, and 20-40%) from national forests in the Superior Uplands area (includes Boundary Waters Canoe Area, Rainbow Lakes, Sylvania, Moquah Barrens, and other Wilderness and Natural areas). The soils were Haplorthods and Udipsamments mainly from outwash plains.The soil columns were instrumented and reburied around a subterranean structure used to collect leachate water and to maintain natural temperature, air, and light conditions. Three humus treatments were applied to soil column (none, northern hardwood, and jack pine) to measure the effect of natural acidification compared to acidification by acid precipitation. The cores were treated with precipitation buffered to pH 5.4 to simulate natural rain and pH 4.2 to simulate acid rain.Columns were treated in 1985 and 1986 with approximately 200 cm of buffered precipitation each year over the frost-free season. Data is

  9. Acidification of soil-water in low base-saturated sand soils of the superior uplands under acid and normal precipitation.

    PubMed

    Harris, A R

    1989-04-01

    Lakes and streams are acidified by direct precipitation and water channeled through nearby soils, but water in low base-saturation soils can produce highly acidic percolate after prolonged contact and subsequent degassing in surface waters. Theories advanced by Reuss (1983), Reuss and Johnson (1985), and Seip and Rustad (1984) suggest that soils with less than 15% base saturation are susceptible to soil-water pH depression of up to 0.4 unit, which is sufficient to cause negative alkalinity in soil solutions. High concentrations of mobile anions (notably sulfate) are responsible for the negative alkalinity and these solutions on CO2 degassing in surface waters can retain acidities equivalent to a pH value of 5.0 or less. This mechanism purports to explain why some lakes acidify when they are surrounded by acid soils and cation leaching is not required.Ambient precipitation set to pH 5.4 and pH 4.2 was applied to columns of low base-saturated, sand, soils, starting in 1985. The columns (15 cm diameter and 150 cm long) were collected from soils with base saturations falling into one of three groups (0-10, 10-20, and 20-40%) from national forests in the Superior Uplands area (includes Boundary Waters Canoe Area, Rainbow Lakes, Sylvania, Moquah Barrens, and other Wilderness and Natural areas). The soils were Haplorthods and Udipsamments mainly from outwash plains.The soil columns were instrumented and reburied around a subterranean structure used to collect leachate water and to maintain natural temperature, air, and light conditions. Three humus treatments were applied to soil column (none, northern hardwood, and jack pine) to measure the effect of natural acidification compared to acidification by acid precipitation. The cores were treated with precipitation buffered to pH 5.4 to simulate natural rain and pH 4.2 to simulate acid rain.Columns were treated in 1985 and 1986 with approximately 200 cm of buffered precipitation each year over the frost-free season. Data is

  10. A phylogenetic approach to the early evolution of autotrophy: the case of the reverse TCA and the reductive acetyl-CoA pathways.

    PubMed

    Becerra, Arturo; Rivas, Mario; García-Ferris, Carlos; Lazcano, Antonio; Peretó, Juli

    2014-06-01

    In recent decades, a number of hypotheses on the autotrophic origin of life have been presented. These proposals invoke the emergence of reaction networks leading from CO or CO₂ to the organic molecules required for life. It has also been suggested that the last (universal) common ancestor (LCA or LUCA) of all extant cell lineages was a chemolitho-autotrophic thermophilic anaerobe. The antiquity of some carbon fixation pathways, the phylogenetic basal distribution of some autotrophic organisms, and the catalytic properties of iron-sulfur minerals have been advanced in support of these ideas. Here we critically examine the phylogenetic distribution and evolution of enzymes that are essential for two of the most ancient autotrophic means of metabolism: the reductive tricarboxylic acid (rTCA) cycle and the reductive acetyl-CoA pathway. Phylogenetic analysis of citryl-CoA synthetase and of citryl-CoA lyase, key enzymatic components of the rTCA cycle, and of CO dehydrogenase/acetyl-CoA synthase, a key enzyme in the reductive acetyl-CoA pathway, revealed that all three enzymes have undergone major lateral transfer events and therefore cannot be used as proof of the LCA's metabolic abilities nor as evidence of an autotrophic origin of life. PMID:26418853

  11. Correlation between precipitation and geographical location of the δ2H values of the fatty acids in milk and bulk milk powder

    NASA Astrophysics Data System (ADS)

    Ehtesham, E.; Baisden, W. T.; Keller, E. D.; Hayman, A. R.; Van Hale, R.; Frew, R. D.

    2013-06-01

    Hydrogen isotope ratios (δ2H) have become a tool for food traceability and authentication of agricultural products. The principle is that the isotopic composition of the produce is influenced by environmental and biological factors and hence exhibits a spatial differentiation of δ2H. This study investigates the variation in δ2H values of New Zealand milk, both in the bulk powder and individual fatty acids extracted from milk samples from dairy factories across New Zealand. Multivariate statistical analyses were used to test for relationships between δ2H of bulk milk powder, milk fatty acid and geographical location. Milk powder samples from different regions of New Zealand were found to exhibit patterns in isotopic composition similar to the corresponding regional precipitation associated with their origin. A model of δ2H in precipitation was developed based on measurements between 2007 and 2010 at 51 stations across New Zealand (Frew and Van Hale, 2011). The model uses multiple linear regressions to predict daily δ2H from 2 geographic and 5 rain-weighted climate variables from the 5 × 5 km New Zealand Virtual Climate Station Network (VCSN). To approximate collection radius for a drying facility the modelled values were aggregated within a 50 km radius of each dairy factory and compared to observed δ2H values of precipitation and bulk milk powder. Daily δ2H predictions for the period from August to December for the area surrounding the sample collection sites were highly correlated with the δ2H values of bulk milk powder. Therefore the δ2H value of milk fatty acids demonstrates promise as a tool for determining the provenance of milk powders and products where milk powder is an ingredient. Separation of milk powder origin to geographic sub-regions within New Zealand was achieved. Hydrogen isotope measurements could be used to complement traditional tracking systems in verifying point of origin.

  12. Low-molecular-weight organic acids in the Tibetan Plateau: Results from one-year of precipitation samples at the SET station

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Kang, Shichang; Sun, Jimin; Wan, Xin; Wang, Yongjie; Gao, Shaopeng; Cong, Zhiyuan

    2014-04-01

    Background atmospheric organic acids: formic (F), acetic (A), oxalic (O), and methanesulfonic (MSA, abbreviated to M) acids in the southern Tibetan Plateau (TP), were determined in one-year of precipitation measurements at a remote alpine station. These organic acids were dominated by oxalic (volume-weighted mean of 0.51 μmol l-1)/formic acid (0.38 μmol l-1), followed by acetic acid (0.20 μmol l-1) and MSA (0.10 μmol l-1). Their levels were comparable with those from other remote sites, while they were lower than those found in populated areas. The South Asian monsoon is responsible for the seasonal variation of organic acid concentration: a relative abundance of MSA and lower concentrations of other organic acids (by the dilution effect) in the monsoon season, while opposite in the non-monsoon season. Diverse sources were identified by principal component analysis combined with the corresponding tracers. These were anthropogenic disturbances (which explain 41% of the variance), marine emission (24%), and biogenic emission (16%). Moreover, the variances of F/A, M/(F + A), and O/(F + A) in monsoonal versus non-monsoonal samples, were involved with the changes of sources. Furthermore, these chemical indexes suggest that active photochemistry over the TP was significant for the production of organic acids and consequently enhanced the ratios of M/(F + A) and O/(F + A) in monsoonal rainfalls. The elevated organic compounds within the ascending tropical moisture imply potential significances for the secondary formation of organic acids in the high-altitude and the changes of the Asian monsoon.

  13. Spur gears: Optimal geometry, methods for generation and Tooth Contact Analysis (TCA) program

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Zhang, Jiao

    1988-01-01

    The contents of this report include the following: (1) development of optimal geometry for crowned spur gears; (2) methods for their generation; and (3) tooth contact analysis (TCA) computer programs for the analysis of meshing and bearing contact on the crowned spur gears. The method developed for synthesis is used for the determination of the optimal geometry for crowned pinion surface and is directed to reduce the sensitivity of the gears to misalignment, localize the bearing contact, and guarantee the favorable shape and low level of the transmission errors. A new method for the generation of the crowned pinion surface has been proposed. This method is based on application of the tool with a surface of revolution that slightly deviates from a regular cone surface. The tool can be used as a grinding wheel or as a shaver. The crowned pinion surface can also be generated by a generating plane whose motion is provided by an automatic grinding machine controlled by a computer. The TCA program simulates the meshing and bearing contact of the misaligned gears. The transmission errors are also determined.

  14. Topology of modified helical gears and Tooth Contact Analysis (TCA) program

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Zhang, Jiao

    1989-01-01

    The contents of this report covers: (1) development of optimal geometries for crowned helical gears; (2) a method for their generation; (3) tooth contact analysis (TCA) computer programs for the analysis of meshing and bearing contact of the crowned helical gears; and (4) modelling and simulation of gear shaft deflection. The developed method for synthesis was used to determine the optimal geometry for a crowned helical pinion surface and was directed to localize the bearing contact and guarantee favorable shape and a low level of transmission errors. Two new methods for generation of the crowned helical pinion surface are proposed. One is based on the application of a tool with a surface of revolution that slightly deviates from a regular cone surface. The tool can be used as a grinding wheel or as a shaver. The other is based on a crowning pinion tooth surface with predesigned transmission errors. The pinion tooth surface can be generated by a computer-controlled automatic grinding machine. The TCA program simulates the meshing and bearing contact of the misaligned gears. The transmission errors are also determined. The gear shaft deformation was modelled and investigated. It was found that the deflection of gear shafts has the same effect as gear misalignment.

  15. Effect of the quantity and duration of application of simulated acid precipitation on nitrogen mineralization and nitrification in a forest soil

    SciTech Connect

    Klein, T.M.; Alexander, M.

    1986-01-01

    A study was conducted of the influence of the rate of application of simulated acid rain on N mineralization and nitrification in a forest soil. The rates were varied by applying different quantities of simulated rain for varying periods of time. The soil was exposed in the laboratory to simulated rain at pH 3.5, 4.1,, or 5.6 at rates equivalent to 1.5, 2.3, 4.6, 7.1 or 15 times the average rate of precipitation in the field and then mineralization of soil N or oxidation of added ammonium was determined. The rates of N mineralization were inhibited by precipitation at pH 3.5 or 4.1 when applied for 27-234 days at rates 1.5 times greater than that which occurs in nature. N mineralization was not affected by simulated rain at pH 3.5 or 4.1 in soils exposed for 156 days at 2.3 times the natural rate of precipitation, for 27 or 81 days at 4.6 times the natural rate, for 54 days at 7.1 times the natural rate, or for 234 day at 15 times the natural rate. (Copyright (c) 1986 by D. Reidel Publishing Company).

  16. Bioprocess monitoring: minimizing sample matrix effects for total protein quantification with bicinchoninic acid assay.

    PubMed

    Reichelt, Wieland N; Waldschitz, Daniel; Herwig, Christoph; Neutsch, Lukas

    2016-09-01

    Determining total protein content is a routine operation in many laboratories. Despite substantial work on assay optimization interferences, the widely used bicinchoninic acid (BCA) assay remains widely recognized for its robustness. Especially in the field of bioprocess engineering the inaccuracy caused by interfering substances remains hardly predictable and not well understood. Since the introduction of the assay, sample pre-treatment by trichloroacetic acid (TCA) precipitation has been indicated as necessary and sufficient to minimize interferences. However, the sample matrix in cultivation media is not only highly complex but also dynamically changing over process time in terms of qualitative and quantitative composition. A significant misestimation of the total protein concentration of bioprocess samples is often observed when following standard work-up schemes such as TCA precipitation, indicating that this step alone is not an adequate means to avoid measurement bias. Here, we propose a modification of the BCA assay, which is less influenced by sample complexity. The dynamically changing sample matrix composition of bioprocessing samples impairs the conventional approach of compensating for interfering substances via a static offset. Hence, we evaluated the use of a correction factor based on an internal spike measurement for the respective samples. Using protein spikes, the accuracy of the BCA protein quantification could be improved fivefold, taking the BCA protein quantification to a level of accuracy comparable to other, more expensive methods. This will allow reducing expensive iterations in bioprocess development to due inaccurate total protein analytics. PMID:27314233

  17. Upregulation of PTEN suppresses invasion in Tca8113 tongue cancer cells through repression of epithelial-mesenchymal transition (EMT).

    PubMed

    Xie, Siming; Lu, Zhiyuan; Lin, Yanzhu; Shen, Lijia; Yin, Cao

    2016-05-01

    We previously discovered that the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) was downregulated in the majority patients with tongue squamous cell carcinoma (TSCC). The aim of this study was to investigate the role of PTEN overexpression in the regulation of epithelial-mesenchymal transition (EMT) of the tongue squamous carcinoma cell line Tca8113 as well as explore the underlying mechanism. GV230 (containing the PTEN gene) and empty vectors were transfected into Tca8113 cells. After stable transfection, the messenger RNA (mRNA) and protein levels of PTEN were validated using quantitative real-time PCR (qPCR) and Western blot analysis. The growth and cell cycle were analyzed using Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. The invasion ability was measured with a transwell assay. The effects of PTEN overexpression on EMT and Hedgehog signaling were assessed by comparing Tca8113-PTEN cells with control and negative control cell groups. We found that PTEN expression was significantly upregulated after transfection. Meanwhile, upregulated PTEN inhibited the proliferation and invasion of Tca8113 cells. In addition, we observed changes in the EMT- and Hedgehog-associated proteins. These data demonstrated that PTEN upregulation could reduce invasion by inhibiting the process of EMT in Tca8113 cells, which might be related to the Hedgehog signaling pathway.

  18. Upregulation of PTEN suppresses invasion in Tca8113 tongue cancer cells through repression of epithelial-mesenchymal transition (EMT).

    PubMed

    Xie, Siming; Lu, Zhiyuan; Lin, Yanzhu; Shen, Lijia; Yin, Cao

    2016-05-01

    We previously discovered that the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) was downregulated in the majority patients with tongue squamous cell carcinoma (TSCC). The aim of this study was to investigate the role of PTEN overexpression in the regulation of epithelial-mesenchymal transition (EMT) of the tongue squamous carcinoma cell line Tca8113 as well as explore the underlying mechanism. GV230 (containing the PTEN gene) and empty vectors were transfected into Tca8113 cells. After stable transfection, the messenger RNA (mRNA) and protein levels of PTEN were validated using quantitative real-time PCR (qPCR) and Western blot analysis. The growth and cell cycle were analyzed using Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. The invasion ability was measured with a transwell assay. The effects of PTEN overexpression on EMT and Hedgehog signaling were assessed by comparing Tca8113-PTEN cells with control and negative control cell groups. We found that PTEN expression was significantly upregulated after transfection. Meanwhile, upregulated PTEN inhibited the proliferation and invasion of Tca8113 cells. In addition, we observed changes in the EMT- and Hedgehog-associated proteins. These data demonstrated that PTEN upregulation could reduce invasion by inhibiting the process of EMT in Tca8113 cells, which might be related to the Hedgehog signaling pathway. PMID:26649861

  19. Acid precipitation - (Part I). Hearings before the Subcommittee on Health and the Environment of the Committee on Energy and Commerce, House of Representatives, Ninety-Seventh Congress, First Session on Effects and Solutions to Combat Acid Precipitation

    SciTech Connect

    Not Available

    1982-01-01

    Part 1 of the record covers three days of hearings on effects of acid rain and possible solutions to combat it. The 24 witnesses include a panel of business representatives from the Adirondacks area of New York, spokesmen from four other states affected by acid rain, and representatives of the Northeast States, all of whom described the threat to animal life in the lakes and streams, to lumber, and to human life because of acidification.

  20. ADVANCES IN BIOTREATMENT OF ACID MINE DRAINAGE AND BIORECOVERY OF METALS: 1. METAL PRECIPITATION FOR RECOVERY AND RECYCLE

    EPA Science Inventory

    Acid-mine drainage (AMD) is a severe pollution problem attributed to past mining activities. AMD is an acidic, metal-bearing wastewater generated by the oxidation of metal sulfides to sulfates by Thiobacillus bacteria in both active and abandoned mining operations. The wastewater...

  1. URANIUM PRECIPITATION PROCESS

    DOEpatents

    Thunaes, A.; Brown, E.A.; Smith, H.W.; Simard, R.

    1957-12-01

    A method for the recovery of uranium from sulfuric acid solutions is described. In the present process, sulfuric acid is added to the uranium bearing solution to bring the pH to between 1 and 1.8, preferably to about 1.4, and aluminum metal is then used as a reducing agent to convert hexavalent uranium to the tetravalent state. As the reaction proceeds, the pH rises amd a selective precipitation of uranium occurs resulting in a high grade precipitate. This process is an improvement over the process using metallic iron, in that metallic aluminum reacts less readily than metallic iron with sulfuric acid, thus avoiding consumption of the reducing agent and a raising of the pH without accomplishing the desired reduction of the hexavalent uranium in the solution. Another disadvantage to the use of iron is that positive ferric ions will precipitate with negative phosphate and arsenate ions at the pH range employed.

  2. Long-term exposure of Sitka spruce seedlings to trichloroacetic acid.

    PubMed

    Cape, J Neil; Reeves, Nicholas M; Schröder, Peter; Heal, Mathew R

    2003-07-01

    Trichloroacetic acid (TCA) has been implicated as an airborne pollutant responsible for adverse effects on forest health. There is considerable debate as to whether TCA observed in trees and forest soils is derived from atmospheric deposition or from in situ production. This experiment reports the results from treating 4-year-old Sitka spruce (Picea sitchensis (Bong.) Carr) plants in a greenhouse over a growing season with TCA supplied either to the soil or to the foliage at concentrations of 10 and 100 ng mL(-1). Similar uptake of TCA by needles was observed for both modes of treatment, with significant accumulation of TCA (300 ng g(-1) dry wt) at the higher concentration. Larger concentrations in stem tissue were seen for the foliar-applied TCA (280 ng g(-1)) than for the soil-applied TCA (70 ng g(-1)), suggesting that direct stem uptake may be important. Six months after treatments stopped, TCA concentrations in the needles of plants exposed to 100 ng mL(-1) TCA were still enhanced, showing that biological degradation of TCA in needles was slow over the winter. By contrast, no significant enhancement of TCA in soil could be detected in the directly treated soils even during the experiment. The protein content of needles treated with the higher concentration of TCA by either route was significantly smaller than for the controls, but there was no effect of TCA on the conjugation of 1-chloro-2,4-dinitrobenzene in roots nor on the conjugation of 1,2-dichloro-4-nitrobenzene in needles.

  3. Trichloroacetic acid in the environment.

    PubMed

    McCulloch, A

    2002-05-01

    Suppositions that the trichloroacetic acid (TCA, CCl3C(O)OH) found in nature was a consequence solely of the use of chlorinated hydrocarbon solvents prompted this critical review of the literature on its environmental fluxes and occurrences. TCA is widely distributed in forest soils (where it was rarely used as an herbicide) and measurements suggest a soil flux of 160 000 tonnes yr(-1) in European forests alone. TCA is also produced during oxidative water treatment and the global flux could amount to 55 000 tonnes yr(-1) (from pulp and paper manufacture, potable water and cooling water treatments). By contrast, the yields of TCA from chlorinated hydrocarbon solvents are small: from tetrachloroethene 13 600 tonnes yr(-1) and from 1,1,1-trichloroethane 4300 tonnes yr(-1) on a global basis, at the atmospheric burdens and removal rates typical of the late 1990s. TCA is ubiquitous in rainwater and snow. Its concentrations are highly variable and the variations cannot be connected with location or date. However, there is no significant difference between the concentrations found in Chile and in eastern Canada (by the same analysts), or between Malawi and western Canada, or between Antarctica and Switzerland, nor any significant difference globally between the concentrations in cloud, rain and snow (although local enhancement in fog water has been shown). TCA is present in old ice and firn. At the deepest levels, the firn was deposited early in the 19th century, well before the possibility of contamination by industrial production of reactive chlorine, implying a non-industrial background. This proposition is supported by plume measurements from pulp mills in Finland. TCA is ubiquitous in soils; concentrations are very variable but there are some indications that soils under coniferous trees contain higher amounts. The concentrations of TCA found in plant tissue are region-specific and may also be plant-specific, to the extent that conifers seem to contain more than other

  4. Production and functional evaluation of a protein concentrate from giant squid (Dosidicus gigas) by acid dissolution and isoelectric precipitation.

    PubMed

    Cortés-Ruiz, Juan A; Pacheco-Aguilar, Ramón; Elena Lugo-Sánchez, M; Gisela Carvallo-Ruiz, M; García-Sánchez, Guillermina

    2008-09-15

    A protein concentrate from giant squid (Dosidicus gigas) was produced under acidic conditions and its functional-technological capability evaluated in terms of its gel-forming ability, water holding capacity and colour attributes. Technological functionality of the concentrate was compared with that of squid muscle and a neutral concentrate. Protein-protein aggregates insoluble at high ionic strength (I=0.5M), were detected in the acidic concentrate as result of processing with no preclusion of its gel-forming ability during the sol-to-gel thermal transition. Even though washing under acidic condition promoted autolysis of the myosin heavy chain, the acidic concentrate displayed an outstanding ability to gel giving samples with a gel strength of 455 and 1160gcm at 75% and 90% compression respectively, and an AA folding test grade indicative of high gel strength, elasticity, and cohesiveness. The process proved to be a good alternative for obtaining a functional protein concentrate from giant squid muscle.

  5. Acid precipitation: Effects on fresh water ecosystems. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1993-05-01

    The bibliography contains citations concerning the effects of acidification on fresh water ecosystems. Algae and diatom distribution, survival and reproduction rates of specific fish species under acid lake conditions, and tolerance to stress caused by acidic conditions in fresh water ecosystems are studied. Effects of water pH on trace metal toxicity to fresh water organisms are briefly considered. Control and reduction of acidification are excluded from this bibliography. (Contains 250 citations and includes a subject term index and title list.)

  6. LC-MS/MS analysis of Δ9-tetrahydrocannabinolic acid A in serum after protein precipitation using an in-house synthesized deuterated internal standard.

    PubMed

    Wohlfarth, Ariane; Roth, Nadine; Auwärter, Volker

    2012-06-01

    An assay based on liquid chromatography/tandem mass spectrometry is presented for the fast, precise and sensitive quantitation of Δ9-tetrahydrocannabinolic acid A (THCA) in serum. THCA is the biogenetic precursor of Δ9-tetrahydrocannabinol in cannabis and has aroused interest in the pharmacological and forensic field especially as a potential marker for recent cannabis use. After addition of deuterated THCA, synthesized from D(3)-THC as starting material, and protein precipitation, the analytes were separated using gradient elution on a Luna C18 column (150 × 2.0 mm × 5 µm) with 0.1% formic acid and acetonitrile/0.1% formic acid. Data acquisition was performed on a triple quadrupole linear ion trap mass spectrometer in multiple reaction monitoring mode with negative electrospray ionization. After optimization, the following sample preparation procedure was used: 200 μL serum was spiked with internal standard solution and methanol and then precipitated 'in fractions' with 500 μL ice-cold acetonitrile. After storage and centrifugation, the supernatant was evaporated and the residue redissolved in mobile phase. The assay was fully validated according to international guidelines including, for the first time, the assessment of matrix effects and stability experiments. Limit of detection was 0.1 ng/mL, and limit of quantification was 1.0 ng/mL. The method was found to be selective and proved to be linear over a range of 1.0 to 100 ng/mL using a 1/x weighted calibration model with regression coefficients >0.9996. Accuracy and precision data were within the required limits (RSD ≤ 8.6%, bias: 2.4 to 11.4%), extractive yield was greater than 84%. The analytes were stable in serum samples after three freeze/thaw cycles and storage at -20 °C for one month.

  7. Design and evaluation of a downconverter based on MicroTCA.4

    NASA Astrophysics Data System (ADS)

    Gan, Nan; Liu, Rong; Ma, Xin-Peng; Chi, Yun-Long

    2016-07-01

    Modern low-level RF (LLRF) control systems of particle accelerators are designed to achieve extremely precise field amplitude and phase regulation inside the accelerating cavities. The RF field signal is usually converted to an intermediate frequency (IF) before being sampled by ADC. As the down-conversion is an important procedure of digital signal processing in LLRF system, designing a high performance and broad band downconverter compatible with various accelerators is important. In this paper, the design of a downconverter based on MicroTCA and its performance evaluation on different frequency points are presented. The major design objective of this module is a wider operating frequency range and more flexibility in application.

  8. HSulf-1 deficiency dictates a metabolic reprograming of glycolysis and TCA cycle in ovarian cancer.

    PubMed

    Mondal, Susmita; Roy, Debarshi; Camacho-Pereira, Juliana; Khurana, Ashwani; Chini, Eduardo; Yang, Lifeng; Baddour, Joelle; Stilles, Katherine; Padmabandu, Seth; Leung, Sam; Kalloger, Steve; Gilks, Blake; Lowe, Val; Dierks, Thomas; Hammond, Edward; Dredge, Keith; Nagrath, Deepak; Shridhar, Viji

    2015-10-20

    Warburg effect has emerged as a potential hallmark of many cancers. However, the molecular mechanisms that led to this metabolic state of aerobic glycolysis, particularly in ovarian cancer (OVCA) have not been completely elucidated. HSulf-1 predominantly functions by limiting the bioavailability of heparan binding growth factors and hence their downstream signaling. Here we report that HSulf-1, a known putative tumor suppressor, is a negative regulator of glycolysis. Silencing of HSulf-1 expression in OV202 cell line increased glucose uptake and lactate production by upregulating glycolytic genes such as Glut1, HKII, LDHA, as well as metabolites. Conversely, HSulf-1 overexpression in TOV21G cells resulted in the down regulation of glycolytic enzymes and reduced glycolytic phenotype, supporting the role of HSulf-1 loss in enhanced aerobic glycolysis. HSulf-1 deficiency mediated glycolytic enhancement also resulted in increased inhibitory phosphorylation of pyruvate dehydrogenase (PDH) thus blocking the entry of glucose flux into TCA cycle. Consistent with this, metabolomic and isotope tracer analysis showed reduced glucose flux into TCA cycle. Moreover, HSulf-1 loss is associated with lower oxygen consumption rate (OCR) and impaired mitochondrial function. Mechanistically, lack of HSulf-1 promotes c-Myc induction through HB-EGF-mediated p-ERK activation. Pharmacological inhibition of c-Myc reduced HB-EGF induced glycolytic enzymes implicating a major role of c-Myc in loss of HSulf-1 mediated altered glycolytic pathway in OVCA. Similarly, PG545 treatment, an agent that binds to heparan binding growth factors and sequesters growth factors away from their ligand also blocked HB-EGF signaling and reduced glucose uptake in vivo in HSulf-1 deficient cells. PMID:26378042

  9. The TCA cycle is not required for selection or survival of multidrug-resistant Salmonella

    PubMed Central

    Ricci, Vito; Loman, Nick; Pallen, Mark; Ivens, Alasdair; Fookes, Maria; Langridge, Gemma C.; Wain, John; Piddock, Laura J. V.

    2012-01-01

    Objectives The initial aim of this study was to use a systems biology approach to analyse a ciprofloxacin-selected multidrug-resistant (MDR) Salmonella enterica serotype Typhimurium, L664. Methods The whole genome sequence and transcriptome of L664 were analysed. Site-directed mutagenesis to recreate each mutation was carried out, followed by phenotypic characterization and mutation frequency analysis. As a mutation in the TCA cycle was detected we tested the controversial hypothesis regarding the bacterial response to bactericidal antibiotics, put forward by Kohanski et al. (Cell 2007; 130: 797–810 and Mol Cell 2010; 37: 311–20), that exposure of bacteria to agents such as ciprofloxacin produces reactive oxygen species (ROS), which transiently increase the mutation rate giving rise to MDR bacteria. Results L664 contained a mutation in ramR that conferred MDR. A mutation in tctA affected the TCA cycle and conferred the inability to grow on minimal agar. The virulence of L664 was not attenuated. Ciprofloxacin exposure produced ROS in L664 and SL1344 (tctA::aph), but it was reduced and occurred later. There were no significant differences in the rates of killing or mutations per generation to antibiotic resistance between the strains. Conclusions Whilst we confirm production of ROS in response to ciprofloxacin, we have no data to support the hypothesis that this leads to selection of MDR strains. Our results indicate that the mutations in tctA and glgA were random as they did not pre-exist in the parental strain, and that the mutation in tctA did not provide a survival advantage or disadvantage in the presence of antibiotic. PMID:22186876

  10. Production and functional evaluation of a protein concentrate from giant squid (Dosidicus gigas) by acid dissolution and isoelectric precipitation.

    PubMed

    Cortés-Ruiz, Juan A; Pacheco-Aguilar, Ramón; Elena Lugo-Sánchez, M; Gisela Carvallo-Ruiz, M; García-Sánchez, Guillermina

    2008-09-15

    A protein concentrate from giant squid (Dosidicus gigas) was produced under acidic conditions and its functional-technological capability evaluated in terms of its gel-forming ability, water holding capacity and colour attributes. Technological functionality of the concentrate was compared with that of squid muscle and a neutral concentrate. Protein-protein aggregates insoluble at high ionic strength (I=0.5M), were detected in the acidic concentrate as result of processing with no preclusion of its gel-forming ability during the sol-to-gel thermal transition. Even though washing under acidic condition promoted autolysis of the myosin heavy chain, the acidic concentrate displayed an outstanding ability to gel giving samples with a gel strength of 455 and 1160gcm at 75% and 90% compression respectively, and an AA folding test grade indicative of high gel strength, elasticity, and cohesiveness. The process proved to be a good alternative for obtaining a functional protein concentrate from giant squid muscle. PMID:26049243

  11. Amino acid and mineral composition of protein and other components and their recovery yields from whole Antarctic krill (Euphausia superba) using isoelectric solubilization/precipitation.

    PubMed

    Chen, Y-C; Tou, J C; Jaczynski, J

    2009-03-01

    Proteins and insolubles were recovered from whole Antarctic krill via novel isoelectric solubilization/precipitation using different pH treatments. The protein recovery yield was 45% to 50% (dry basis). The recovered proteins had higher (P < 0.05) content of essential amino acids (EAAs) and non-EAAs as well as higher (P < 0.05) ratio of total EAA/total AA than whole krill. The EAAs constituted almost 50% of total AAs. The least extreme pH treatments (pHs 3 and 12) yielded highest (P < 0.05) content of EAAs. The quality of recovered proteins was high based on EAAs meeting FAO/WHO/UNU recommendations for adults and infants. The basic pH yielded proteins with the lowest (P < 0.05) amount of minerals and the highest (P < 0.05) amount of Ca, P, and Mg in the insolubles when compared to the acidic treatments. However, both basic and acidic treatments effectively removed minerals from recovered proteins without the removal of the exoskeleton before processing. Therefore, besides high-quality proteins, the insolubles may provide a mineral supplement in the animal diet.

  12. Acid precipitation and food quality: Inhibition of growth and survival in black ducks and mallards by dietary aluminum, calcium and phosphorus

    USGS Publications Warehouse

    Sparling, D.W.

    1990-01-01

    In areas impacted by acid precipitation, water chemistry of acidic ponds and streams often changes, resulting in increased mobilization of aluminum and decreased concentration of calcium carbonate. Aluminum binds with phosphorus and inhibits its uptake by organisms. Thus, invertebrate food organisms used by waterfowl may have inadequate Ca and P or elevated Al for normal growth and development. Acid rain and its effects may be one of the factors negatively impacting American black ducks (Anas rubripes) in eastern North America. One-day old mallards (A. platyrhynchos) and black ducks were placed on one of three Ca:P regimens: low:low (LL), normal:normal (NN), and low:high (LH) with each regimen divided further into three or four Al levels for 10 weeks. Forty-five % of the black ducks died on nine different diets whereas only 28% of the mallards died on three different diets. Mortality was significantly related to diet in both species. Growth rates for body weight, culmens, wings, and tarsi of both species on control diets exceeded those on many treatment diets but the differences were less apparent for mallards than for black ducks. Differences among treatments were due to both Ca:P and Al levels.

  13. Acid precipitation and food quality: inhibition of growth and survival in black ducks and mallards by dietary aluminum, calcium, and phosphorus.

    PubMed

    Sparling, D W

    1990-01-01

    In areas impacted by acid precipitation, water chemistry of acidic ponds and streams often changes, resulting in increased mobilization of aluminum and decreased concentration of calcium carbonate. Aluminum binds with phosphorus and inhibits its uptake by organisms. Thus, invertebrate food organisms used by waterfowl may have inadequate Ca and P or elevated Al for normal growth and development. Acid rain and its effects may be one of the factors negatively impacting American black ducks (Anas rubripes) in eastern North America. One-day old mallards (A. platyrhynchos) and black ducks were placed on one of three Ca:P regimens: low:low (LL), normal:normal (NN), and low:high (LH) with each regimen divided further into three or four Al levels for 10 weeks. Forty-five % of the black ducks died on nine different diets whereas only 28% of the mallards died on three different diets. Mortality was significantly related to diet in both species. Growth rates for body weight, culmens, wings, and tarsi of both species on control diets exceeded those on many treatment diets but the differences were less apparent for mallards than for black ducks. Differences among treatments were due to both Ca:P and Al levels.

  14. Precipitation Recycling

    NASA Technical Reports Server (NTRS)

    Eltahir, Elfatih A. B.; Bras, Rafael L.

    1996-01-01

    The water cycle regulates and reflects natural variability in climate at the regional and global scales. Large-scale human activities that involve changes in land cover, such as tropical deforestation, are likely to modify climate through changes in the water cycle. In order to understand, and hopefully be able to predict, the extent of these potential global and regional changes, we need first to understand how the water cycle works. In the past, most of the research in hydrology focused on the land branch of the water cycle, with little attention given to the atmospheric branch. The study of precipitation recycling which is defined as the contribution of local evaporation to local precipitation, aims at understanding hydrologic processes in the atmospheric branch of the water cycle. Simply stated, any study on precipitation recycling is about how the atmospheric branch of the water cycle works, namely, what happens to water vapor molecules after they evaporate from the surface, and where will they precipitate?

  15. Water resource baseline data and assessment of impacts from acidic precipitation, Acadia National Park, Maine. Technical report (Final)

    SciTech Connect

    Kahl, J.S.; Andersen, J.L.; Norton, S.A.

    1985-06-01

    The chemistries of 18 lakes and 23 streams were studied at Acadia National Park, Maine during 1982-84. ANP is located on granitic bedrock, with thin to non-existent soils and steep topography, resulting in poorly buffered, oligotrophic surface waters. Mean baseflow pH was 5.93, 6.48 and 6.39 for the first-order brooks, second-order streams, and lakes, respectively. Alkalinities were 56, 140, and 61 micro eq/1. During high flow events, pH and alkalinity were depressed, partly due to titration by strong acids; dilution was estimated to account for 24 to 60% of the alkalinity declines. At least twice, HCI unrelated to atmospheric deposition was responsible for depressing alkalinities. The HCI was apparently generated from an NaCI salt-effect in soils. However, metal stratigraphy of cores from 3 lakes indicates that air pollution and presumably acidic deposition, began more than 100 years ago.

  16. Extraction-less, rapid assay for the direct detection of 2,4,6-trichloroanisole (TCA) in cork samples.

    PubMed

    Apostolou, Theofylaktos; Pascual, Nuria; Marco, M-Pilar; Moschos, Anastassios; Petropoulos, Anastassios; Kaltsas, Grigoris; Kintzios, Spyridon

    2014-07-01

    2,4,6-trichloroanisole (TCA), the cork taint molecule, has been the target of several analytical approaches over the few past years. In spite of the development of highly efficient and sensitive tools for its detection, ranging from advanced chromatography to biosensor-based techniques, a practical breakthrough for routine cork screening purposes has not yet been realized, in part due to the requirement of a lengthy extraction of TCA in organic solvents, mostly 12% ethanol and the high detectability required. In the present report, we present a modification of a previously reported biosensor system based on the measurement of the electric response of cultured fibroblast cells membrane-engineered with the pAb78 TCA-specific antibody. Samples were prepared by macerating cork tissue and mixing it directly with the cellular biorecognition elements, without any intervening extraction process. By using this novel approach, we were able to detect TCA in just five minutes at extremely low concentrations (down to 0.2 ppt). The novel biosensor offers a number of practical benefits, including a very considerable reduction in the total assay time by one day, and a full portability, enabling its direct employment for on-site, high throughput screening of cork in the field and production facilities, without requiring any type of supporting infrastructure.

  17. 1H nuclear magnetic resonance-based extracellular metabolomic analysis of multidrug resistant Tca8113 oral squamous carcinoma cells

    PubMed Central

    WANG, HUI; CHEN, JIAO; FENG, YUN; ZHOU, WENJIE; ZHANG, JIHUA; YU, YU; WANG, XIAOQIAN; ZHANG, PING

    2015-01-01

    A major obstacle of successful chemotherapy is the development of multidrug resistance (MDR) in the cancer cells, which is difficult to reverse. Metabolomic analysis, an emerging approach that has been increasingly applied in various fields, is able to reflect the unique chemical fingerprints of specific cellular processes in an organism. The assessment of such metabolite changes can be used to identify novel therapeutic biomarkers. In the present study, 1H nuclear magnetic resonance (NMR) spectroscopy was used to analyze the extracellular metabolomic spectrum of the Tca8113 oral squamous carcinoma cell line, in which MDR was induced using the carboplatin (CBP) and pingyangmycin (PYM) chemotherapy drugs in vitro. The data were analyzed using the principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) methods. The results demonstrated that the extracellular metabolomic spectrum of metabolites such as glutamate, glycerophosphoethanol amine, α-Glucose and β-Glucose for the drug-induced Tca8113 cells was significantly different from the parental Tca8113 cell line. A number of biochemicals were also significantly different between the groups based on their NMR spectra, with drug-resistant cells presenting relatively higher levels of acetate and lower levels of lactate. In addition, a significantly higher peak was observed at δ 3.35 ppm in the spectrum of the PYM-induced Tca8113 cells. Therefore, 1H NMR-based metabolomic analysis has a high potential for monitoring the formation of MDR during clinical tumor chemotherapy in the future. PMID:26137105

  18. DISSOLUTION OF LANTHANUM FLUORIDE PRECIPITATES

    DOEpatents

    Fries, B.A.

    1959-11-10

    A plutonium separatory ore concentration procedure involving the use of a fluoride type of carrier is presented. An improvement is given in the derivation step in the process for plutonium recovery by carrier precipitation of plutonium values from solution with a lanthanum fluoride carrier precipitate and subsequent derivation from the resulting plutonium bearing carrier precipitate of an aqueous acidic plutonium-containing solution. The carrier precipitate is contacted with a concentrated aqueous solution of potassium carbonate to effect dissolution therein of at least a part of the precipitate, including the plutonium values. Any remaining precipitate is separated from the resulting solution and dissolves in an aqueous solution containing at least 20% by weight of potassium carbonate. The reacting solutions are combined, and an alkali metal hydroxide added to a concentration of at least 2N to precipitate lanthanum hydroxide concomitantly carrying plutonium values.

  19. Coordination polymers of Fe(iii) and Al(iii) ions with TCA ligand: distinctive fluorescence, CO2 uptake, redox-activity and oxygen evolution reaction.

    PubMed

    Dhara, Barun; Sappati, Subrahmanyam; Singh, Santosh K; Kurungot, Sreekumar; Ghosh, Prasenjit; Ballav, Nirmalya

    2016-04-28

    Fe and Al belong to different groups in the periodic table, one from the p-block and the other from the d-block. In spite of their different groups, they have the similarity of exhibiting a stable 3+ oxidation state. Here we have prepared Fe(iii) and Al(iii) based coordination polymers in the form of metal-organic gels with the 4,4',4''-tricarboxyltriphenylamine (TCA) ligand, namely Fe-TCA and Al-TCA, and evaluated some important physicochemical properties. Specifically, the electrical conductivity, redox-activity, porosity, and electrocatalytic activity (oxygen evolution reaction) of the Fe-TCA system were noted to be remarkably higher than those of the Al-TCA system. As for the photophysical properties, almost complete quenching of the fluorescence originating from TCA was observed in case of the Fe-TCA system, whereas for the Al-TCA system a significant retention of fluorescence with red-shifted emission was observed. Quantum mechanical calculations based on density functional theory (DFT) were performed to unravel the origin of such discriminative behaviour of these coordination polymer systems. PMID:26961352

  20. Coordination polymers of Fe(iii) and Al(iii) ions with TCA ligand: distinctive fluorescence, CO2 uptake, redox-activity and oxygen evolution reaction.

    PubMed

    Dhara, Barun; Sappati, Subrahmanyam; Singh, Santosh K; Kurungot, Sreekumar; Ghosh, Prasenjit; Ballav, Nirmalya

    2016-04-28

    Fe and Al belong to different groups in the periodic table, one from the p-block and the other from the d-block. In spite of their different groups, they have the similarity of exhibiting a stable 3+ oxidation state. Here we have prepared Fe(iii) and Al(iii) based coordination polymers in the form of metal-organic gels with the 4,4',4''-tricarboxyltriphenylamine (TCA) ligand, namely Fe-TCA and Al-TCA, and evaluated some important physicochemical properties. Specifically, the electrical conductivity, redox-activity, porosity, and electrocatalytic activity (oxygen evolution reaction) of the Fe-TCA system were noted to be remarkably higher than those of the Al-TCA system. As for the photophysical properties, almost complete quenching of the fluorescence originating from TCA was observed in case of the Fe-TCA system, whereas for the Al-TCA system a significant retention of fluorescence with red-shifted emission was observed. Quantum mechanical calculations based on density functional theory (DFT) were performed to unravel the origin of such discriminative behaviour of these coordination polymer systems.

  1. IRIS Toxicological Review of Trichloroacetic Acid (External Review Draft)

    EPA Science Inventory

    EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of Trichloroacetic acid (TCA) that when finalized will appear on the Integrated Risk Information System (IRIS) database.

  2. Catalog of Corps of Engineers structure inventories suitable for the acid precipitation-structure materials study. Special report

    SciTech Connect

    Merry, C.J.; McKim, H.L.; Humiston, N.H.

    1985-03-01

    This report contains a survey of Corps of Engineers floodplain inventories. Its purpose was to determine if enough building materials information was available in the Corps data base to be used for predicting the distribution of building materials across the country as part of the EPA acid rain assessment program. The floodplain surveys were rated using the criteria of the date of the survey, the number of buildings, the variety of building materials, the amount of dimensions data listed for the buildings, the land cover types in the data, and whether or not the data were computerized. Six structure inventories were recommended for further study.

  3. CONCENTRATION OF Pu USING AN IODATE PRECIPITATE

    DOEpatents

    Fries, B.A.

    1960-02-23

    A method is given for separating plutonium from lanthanum in a lanthanum fluoride carrier precipitation process for the recovery of plutonium values from an aqueous solution. The carrier precipitation process includes the steps of forming a lanthanum fluoride precipi- . tate, thereby carrying plutonium out of solution, metathesizing the fluoride precipitate to a hydroxide precipitate, and then dissolving the hydroxide precipitate in nitric acid. In accordance with the invention, the nitric acid solution, which contains plutonium and lanthanum, is made 0.05 to 0.15 molar in potassium iodate. thereby precipitating plutonium as plutonous iodate and the plutonous iodate is separated from the lanthanum- containing supernatant solution.

  4. Acid precipitation studies in Colorado and Wyoming: interim report of surveys of montane amphibians and water chemistry

    USGS Publications Warehouse

    Corn, Paul Stephen; Stolzenburg, William; Bury, R. Bruce

    1989-01-01

    Acid deposition may be detrimental or stressful to native populations of wildlife. Because many species of amphibians breed in shallow ponds created by spring rains or melting snow, they may be particularly vulnerable to the effects of acidification. From 1986 to 1988, we surveyed 105 locations in the central Rocky Mountains where amphibians had been recorded previously, and we found that two species of amphibians had experiences major losses. We found the northern leopard frog (Rana pipiens) at only 4 of 33 (12%) historically known localities, and the boreal toad (Bufo boreas) was present at 10 of 59 (17%) known localities. Three other species have not suffered region-wide declines. Tiger salamanders (Ambystoma tigrinum) and wood frogs (Rana sylvatica) were present at 45% and 69% of known localities respectively, and were observed at several localities were they had not been recorded previously. Chorus frogs (Pseudacris triseriata) suffered a catastrophic decline in population size in one population monitored since 1961, but regionally, this species was observed in 36 of 56 (64%) known localities and in another 19 localities where there were no previous records. Complete water chemistry was recorded for 41 localities, and pH was measured at 110 sites in total. Acid neutralizing capacity, pH, specific conductivity, and cation concentrations were negatively correlated with elevation. However, in mountain ponds and lakes, pH was rarely less than 6.0 during the amphibian breeding season. We tested the tolerance of embryos of the four species of frogs to low pH. The LC50 pH was 4.8 for chorus frogs, 4.4-4.7 for leopard frogs, 4.4-4.5 for boreal toads, and 4.2-4.3 for wood frogs. Survival of wood frog embryos declined when exposed to aluminum concentrations of 100 µg/L or greater, but boreal toad embryos survived exposure to aluminum concentrations of 400 µg/L. Acid deposition does not appear to be a major factor in the decline of leopard frogs and boreal toads

  5. Growth response of four species of Eastern hardwood tree seedlings exposed to ozone, acidic precipitation, and sulfur dioxide. [Prunus serotina, Acer rubrum, Quercus rubra, Liriodendron tulipifera

    SciTech Connect

    Davis, D.D. Skelly, J.M. )

    1992-03-01

    In 1987 a study was conducted in controlled environment chambers to determine the foliar sensitivity of tree seedlings of eight species to ozone and acidic precipitation, and to determine the influence of leaf position on symptom severity. Jensen and Dochinger conducted concurrent similar studies in Continuously Stirred Tank Reactor (CSTR) chambers with ten species of forest trees. Based on the results of these initial studies, four species representing a range in foliar sensitivity to ozone were chosen: black cherry (Prunus serotina Ehrh.), red maple (Acer rubrum L.), northern red oak (Quercus rubra L.) and yellow-poplar (Liriodendron tulipifera L.). These species were also chosen because of their ecological and/or commercial importance in Pennsylvania. Seedlings were exposed in growth chambers simulated acid rain. In addition acute exposures to sulfur dioxide were conducted in a regime based on unpublished monitoring data collected near coal-fired power plants. The objective of this study was to determine if the pollutant treatments influenced the growth and productivity of seedlings of these four species. This information will help researchers and foresters understand the role of air pollution in productivity of eastern forests.

  6. Plasma thiobarbituric acid reactivity: reaction conditions and the role of iron, antioxidants and lipid peroxy radicals on the quantitation of plasma lipid peroxides

    SciTech Connect

    Wade, C.R.; van Rij, A.M.

    1988-01-01

    The effects of Fe/sup 3 +/, lipid peroxy radicals and the antioxidant butylated hydroxytoluene on the 2-thiobarbituric (TBA) acid quantitation of plasma lipid peroxides were investigated. Whole plasma and plasma fractions prepared by trichloroacetic acid (TCA) protein precipitation and lipid extraction, demonstrated markedly differing TBA reactivities in the presence or absence of added Fe/sup 3 +/. Examination of the spectral profiles of the TBA reacted whole plasma and TCA precipitated fractions demonstrated the presence of interfering compounds which gave rise to an artifactual increase in lipid peroxide concentrations. In contrast the TBA reacted lipid extracts had low levels of interfering compounds that could be removed by our previously described high pressure liquid chromatographic method. Further characterization of the TBA reactivity of the lipid extract showed that Fe/sup 3 +/ at an optimal concentration of 0.5 mM was necessary for the quantitative decomposition of the lipid peroxides to the TBA reactive product malondialdehyde (MDA). However the presence of Fe/sup 3 +/ resulted in further peroxidation of any unsaturated lipids present.

  7. Global transcription analysis of Krebs tricarboxylic acid cycle mutants reveals an alternating pattern of gene expression and effects on hypoxic and oxidative genes.

    PubMed

    McCammon, Mark T; Epstein, Charles B; Przybyla-Zawislak, Beata; McAlister-Henn, Lee; Butow, Ronald A

    2003-03-01

    To understand the many roles of the Krebs tricarboxylic acid (TCA) cycle in cell function, we used DNA microarrays to examine gene expression in response to TCA cycle dysfunction. mRNA was analyzed from yeast strains harboring defects in each of 15 genes that encode subunits of the eight TCA cycle enzymes. The expression of >400 genes changed at least threefold in response to TCA cycle dysfunction. Many genes displayed a common response to TCA cycle dysfunction indicative of a shift away from oxidative metabolism. Another set of genes displayed a pairwise, alternating pattern of expression in response to contiguous TCA cycle enzyme defects: expression was elevated in aconitase and isocitrate dehydrogenase mutants, diminished in alpha-ketoglutarate dehydrogenase and succinyl-CoA ligase mutants, elevated again in succinate dehydrogenase and fumarase mutants, and diminished again in malate dehydrogenase and citrate synthase mutants. This pattern correlated with previously defined TCA cycle growth-enhancing mutations and suggested a novel metabolic signaling pathway monitoring TCA cycle function. Expression of hypoxic/anaerobic genes was elevated in alpha-ketoglutarate dehydrogenase mutants, whereas expression of oxidative genes was diminished, consistent with a heme signaling defect caused by inadequate levels of the heme precursor, succinyl-CoA. These studies have revealed extensive responses to changes in TCA cycle function and have uncovered new and unexpected metabolic networks that are wired into the TCA cycle.

  8. EFFECT OF MERTHIOLATE (LILLY) ON CERTAIN SPECIFIC PRECIPITATION REACTIONS.

    PubMed

    Pressman, D; Grossberg, A L

    1945-03-01

    Merthiolate (Lilly), a substituted benzoic acid, has been shown to interfere, in concentrations usually used for preservation, with the specific precipitation of antisera against beef serum or sheep serum coupled with diazotized p-aminobenzoic acid, p-arsanilic acid, or p-(p-aminophenylazo) phenylarsonic acid. In some systems increased precipitation was observed, while in others decreased precipitation was observed.

  9. Developmental and anatomical changes in leaves of yellow birch and red kidney bean exposed to simulated acid precipitation

    SciTech Connect

    Paparozzi, E.T.; Tukey, H.B. Jr.

    1983-01-01

    Leaves of Betula alleghaniensis Britt. (yellow birch) and Phaseolus vulgaris L cv. Red Kidney (bean) were examined microscopically during development and after exposure to simulated rain of pH 5.5, 4.3, 3.2, and 2.8. Yellow birch leaves attained maximal leaf area, midvein length, and cuticle thickness at 21 days. Trichomes were either long, unicellular, or multicellular with caplike head and stalk. Epicuticular wax was a bumpy and amorphous layer. The 2nd trifoliolate leaf of red kidney bean attained maximal leaf area, midvein length, and cuticle thickness when the 3rd trifoliolate leaf was expanding. Trichomes present were long, with a unicellular head and a multicellular base; long, unicellular, and terminally hooked; and small and multicellular. Epicuticular wax was present as small irregular flakes. After 2 days of pH 2.8 and 4 days of pH 3.2 simulated acid rain, round yellow and small tan lesions appeared on birch and bean leaves, respectively. Most injury occurred on or between small veins. Most trichome types were uninjured. Lesions formed as a result of collapsed epidermal and highly plasmolyzed palisade cells. The cuticle was still present over injured epidermal cells and epicuticular waxes were unchanged. There was not statistical difference in mean cuticle thickness due to pH of simulated rain. 25 references, 10 figures, 4 tables.

  10. Precipitation Matters

    ERIC Educational Resources Information Center

    McDuffie, Thomas

    2007-01-01

    Although weather, including its role in the water cycle, is included in most elementary science programs, any further examination of raindrops and snowflakes is rare. Together rain and snow make up most of the precipitation that replenishes Earth's life-sustaining fresh water supply. When viewed individually, raindrops and snowflakes are quite…

  11. Effects of acidic deposition on the erosion of carbonate stone - experimental results from the U.S. National Acid Precipitation Assessment Program (NAPAP)

    USGS Publications Warehouse

    Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A.

    1992-01-01

    One of the goals of NAPAP-sponsored research on the effects of acidic deposition on carbonate stone has been to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulfur dioxide and nitrogen oxides on stone erosion. Test briquettes and slabs of freshly quarried Indiana limestone and Vermont marble have been exposed to ambient environmental conditions in a long-term exposure program. Physical measurements of the recession of test stones exposed to ambient conditions at an angle of 30?? to horizontal at the five NAPAP materials exposure sites range from ~15 to ~30?? ??m yr-1 for marble, and from ~25 to ~45 ??m yr -1 for limestone, and are approximately double the recession estimates based on the observed calcium content of run-off solutions from test slabs. The difference between the physical and chemical recession measurements is attributed to the loss of mineral grains from the stone surfaces that are not measured in the run-off experiments. The erosion due to grain loss does not appear to be influenced by rainfall acidity, however, preliminary evidence suggests that grain loss may be influenced by dry deposition of sulfur dioxide between rainfall events. Chemical analyses of the run-off solutions and associated rainfall blanks suggest that ~30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulfur dioxide and nitric acid between rain events. The remaining ~70% of erosion by dissolution is accounted for by the solubility of carbonate stone in rain that is in equilibrium with atmospheric carbon dioxide ('clean rain'). These results are for marble and limestone slabs exposed at an angle of 30?? from horizontal. The relative contribution of sulfur dioxide to chemical erosion is significantly enhanced for stone slabs having an inclination of 60?? or 85??. The dry deposition of alkaline particulate material has a mitigating effect at the two urban field exposure sites at Washington, DC

  12. A general method of protein purification for recombinant unstructured non-acidic proteins.

    PubMed

    Campos, Francisco; Guillén, Gabriel; Reyes, José L; Covarrubias, Alejandra A

    2011-11-01

    Typical late embryogenesis abundant (LEA) proteins accumulate in response to water deficit imposed by the environment or by plant developmental programs. Because of their physicochemical properties, they can be considered as hydrophilins and as a paradigm of intrinsically unstructured proteins (IUPs) in plants. To study their biophysical and biochemical characteristics large quantities of highly purified protein are required. In this work, we report a fast and simple purification method for non-acidic recombinant LEA proteins that does not need the addition of tags and that preserves their in vitro protective activity. The method is based on the enrichment of the protein of interest by boiling the bacterial protein extract, followed by a differential precipitation with trichloroacetic acid (TCA). Using this procedure we have obtained highly pure recombinant LEA proteins of groups 1, 3, and 4 and one recombinant bacterial hydrophilin. This protocol will facilitate the purification of this type of IUPs, and could be particularly useful in proteomic projects/analyses.

  13. Power Effects on High Lift, Stability and Control Characteristics of the TCA Model Tested in the LaRC 14 x 22 Ft Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Glessner, Paul T.

    1999-01-01

    The TCA-2 wind-tunnel test was the second in a series of planned tests utilizing the 5% Technology Concept Airplane (TCA) model. Each of the tests was planned to utilize the unique capabilities of the NASA Langley 14'x22' and the NASA Ames 12' test facilities, in order to assess specific aspects of the high lift and stability and control characteristics of the TCA configuration. However, shortly after the completion of the TCA-1 test, an early projection of the Technology Configuration (TC) identified the need for several significant changes to the baseline TCA configuration. These changes were necessary in order to meet more stringent noise certification levels, as well as, to provide a means to control dynamic structural modes. The projected changes included a change to the outboard wing (increased aspect ratio and lower sweep) and a reconfiguration of the longitudinal control surfaces to include a medium size canard and a reduced horizontal tail. The impact of these proposed changes did not affect the TCA-2 test, because it was specifically planned to address power effects on the empennage and a smaller horizontal tail was in the plan to be tested. However, the focus of future tests was reevaluated and the emphasis was shifted away from assessment of TCA specific configurations to a more general assessment of configurations that encompass the projected design space for the TC.

  14. [Effect of the tumor cell associated glycoconjugate (TCA) derived Kato III, human gastric cancer cells on autologous mixed lymphocyte reaction in patients with rheumatoid arthritis].

    PubMed

    Kashiwagi, N; Ochi, T

    1992-06-01

    We have been developing a new treatment for patients with rheumatoid arthritis (RA) by using intradermal injection of carbohydrate molecule complex. Among them, tumor cell associated glycoconjugate (TCA), the membrane structure of Kato III is one of the effective molecules. We studied the immunomodulatory effect of TCA on the autologous mixed lymphocyte reaction (AMLR) using PWM-mitogen induced lymphoblasts as stimulator cells and peripheral blood mononuclear cells (PBMC) as responder cells. In the kinetic study of the AMLR, its maximum proliferation was observed on days five through seven and responding CD4 cells highly expressed HLA-DR antigen. Studied AMLR in 10 patients with RA, proliferative responses of AMLR in these patients were divided into two types, high and low AMLR types. In vitro examination of TCA on AMLR showed that TCA at a concentration of 250 ng/ml significantly suppressed the AMLR response (p less than 0.01, paired T-test) and this phenomenon was found more frequently in high AMLR type patients than in low AMLR type patients. The suppressive effect of TCA on AMLR had a tendency to correlate with the efficacy of TCA therapy in patients studied. These results suggest that TCA may play a role in regulating the function of autoreactive lymphocytes of patients with RA. PMID:1387980

  15. Electrostatic precipitator with precipitator electrodes

    SciTech Connect

    Junkers, G.

    1980-12-16

    The invention relates to an electrostatic precipitator with collecting electrodes which are arranged in rows adjacent to each other and in respective pairs at equal distances from a respective discharge electrode with which they cooperate. Spring elements are provided between the collecting electrodes and influence the stiffness and oscillating properties of the array of the collecting electrodes.

  16. The Aspergillus nidulans acuL gene encodes a mitochondrial carrier required for the utilization of carbon sources that are metabolized via the TCA cycle.

    PubMed

    Flipphi, Michel; Oestreicher, Nathalie; Nicolas, Valérie; Guitton, Audrey; Vélot, Christian

    2014-07-01

    In Aspergillus nidulans, the utilization of acetate as sole carbon source requires several genes (acu). Most of them are also required for the utilization of fatty acids. This is the case for acuD and acuE, which encode the two glyoxylate cycle-specific enzymes, isocitrate lyase and malate synthase, respectively, but also for acuL that we have identified as AN7287, and characterized in this study. Deletion of acuL resulted in the same phenotype as the original acuL217 mutant. acuL encodes a 322-amino acid protein which displays all the structural features of a mitochondrial membrane carrier, and shares 60% identity with the Saccharomyces cerevisiae succinate/fumarate mitochondrial antiporter Sfc1p (also named Acr1p). Consistently, the AcuL protein was shown to localize in mitochondria, and partial cross-complementation was observed between the S. cerevisiae and A. nidulans homologues. Extensive phenotypic characterization suggested that the acuL gene is involved in the utilization of carbon sources that are catabolized via the TCA cycle, and therefore require gluconeogenesis. In addition, acuL proves to be co-regulated with acuD and acuE. Overall, our data suggest that AcuL could link the glyoxylate cycle to gluconeogenesis by exchanging cytoplasmic succinate for mitochondrial fumarate.

  17. Targeted toxicological screening for acidic, neutral and basic substances in postmortem and antemortem whole blood using simple protein precipitation and UPLC-HR-TOF-MS.

    PubMed

    Telving, Rasmus; Hasselstrøm, Jørgen Bo; Andreasen, Mette Findal

    2016-09-01

    A broad targeted screening method based on broadband collision-induced dissociation (bbCID) ultra-performance liquid chromatography high-resolution time-of-flight mass spectrometry (UPLC-HR-TOF-MS) was developed and evaluated for toxicological screening of whole blood samples. The acidic, neutral and basic substances covered by the method were identified in postmortem and antemortem whole blood samples from forensic autopsy cases, clinical forensic cases and driving under the influence of drugs (DUID) cases by a reverse target database search. The screening method covered 467 substances. Validation was performed on spiked whole blood samples and authentic postmortem and antemortem whole blood samples. For most of the basic drugs, the established cut-off limits were very low, ranging from 0.25ng/g to 50ng/g. The established cut-off limits for most neutral and acidic drugs, were in the range from 50ng/g to 500ng/g. Sample preparation was performed using simple protein precipitation of 300μL of whole blood with acetonitrile and methanol. Ten microliters of the reconstituted extract were injected and separated within a 13.5min UPLC gradient reverse-phase run. Positive electrospray ionization (ESI) was used to generate the ions in the m/z range of 50-1000. Fragment ions were generated by bbCID. Identification was based on retention time, accurate mass, fragment ion(s) and isotopic pattern. A very sensitive broad toxicological screening method using positive electrospray ionization UPLC-HR-TOF-MS was achieved in one injection. This method covered basic substances, substances traditionally analyzed in negative ESI (e.g., salicylic acid), small highly polar substances such as beta- and gamma-hydroxybutyric acid (BHB and GHB, respectively) and highly non-polar substances such as amiodarone. The new method was shown to combine high sensitivity with a very broad scope that has not previously been reported in toxicological whole blood screening when using only one injection

  18. Acid precipitation and food quality: Effects of dietary Al, Ca and P on bone and liver characteristics in American black ducks and mallards

    USGS Publications Warehouse

    Sparling, D.W.

    1991-01-01

    American black ducks (Anas rubripes) and mallards (A. platyrhynchos) were fed diets varying in concentrations of aluminum (Al). calcium (Ca), and phosphorus (P) for 10 weeks to identify toxic effects of Al under conditions representative of areas with acid precipitation. Femur and liver tissues were analyzed for Al. Ca, and P concentrations and structural characteristics. At two weeks of age, both species demonstrated pronounced differences in femur Al and P concentrations and femur mass from dietary Al and interaction between Ca:P regimen and Al:Low Ca:Low P enhanced Al storage and decreased P and mass in femurs. Femur Ca was lowest in the Low Ca:Low P regimen but was not affected by dietary Al. At 10 weeks, femur and liver Al continued to vary with dietary Al. Elevated Al and reduced Ca lowered modulus of elasticity. Femur P increased with elevated dietary P in black ducks. Elevated dietary P negated some of the effects of dietary A! on femur mass in black ducks. Reduced Ca concentrations weakened bones of both species and lowered both Ca and P. An array of clinical signs including lameness, discoloration of the upper mandible, complete and greenstick fractures, and death were responses to elevated Al and Ca:P regimen. Black ducks seemed to display these signs over a wider range of diets than mallards. Diets of 1,000 mg/kg Al had toxic effects on both species, particularly when combined with diets low in Ca and P.

  19. Thiomonas sp. CB2 is able to degrade urea and promote toxic metal precipitation in acid mine drainage waters supplemented with urea

    PubMed Central

    Farasin, Julien; Andres, Jérémy; Casiot, Corinne; Barbe, Valérie; Faerber, Jacques; Halter, David; Heintz, Dimitri; Koechler, Sandrine; Lièvremont, Didier; Lugan, Raphael; Marchal, Marie; Plewniak, Frédéric; Seby, Fabienne; Bertin, Philippe N.; Arsène-Ploetze, Florence

    2015-01-01

    The acid mine drainage (AMD) in Carnoulès (France) is characterized by the presence of toxic metals such as arsenic. Several bacterial strains belonging to the Thiomonas genus, which were isolated from this AMD, are able to withstand these conditions. Their genomes carry several genomic islands (GEIs), which are known to be potentially advantageous in some particular ecological niches. This study focused on the role of the “urea island” present in the Thiomonas CB2 strain, which carry the genes involved in urea degradation processes. First, genomic comparisons showed that the genome of Thiomonas sp. CB2, which is able to degrade urea, contains a urea genomic island which is incomplete in the genome of other strains showing no urease activity. The urease activity of Thiomonas sp. CB2 enabled this bacterium to maintain a neutral pH in cell cultures in vitro and prevented the occurrence of cell death during the growth of the bacterium in a chemically defined medium. In AMD water supplemented with urea, the degradation of urea promotes iron, aluminum and arsenic precipitation. Our data show that ureC was expressed in situ, which suggests that the ability to degrade urea may be expressed in some Thiomonas strains in AMD, and that this urease activity may contribute to their survival in contaminated environments. PMID:26441922

  20. [High aluminum concentrations in well water of southern Lower Saxony sandy soil areas caused by acid precipitation--evaluation from the public health and ecologic viewpoint].

    PubMed

    Mühlenberg, W

    1990-01-01

    Decades of acid precipitation have caused soil acidification in regions with low neutralizing capacity of industrial countries, thus mobilizing aluminium from clay minerals into soil solution and ground water. In the southern sandy heath-land of Lower Saxony all the wells with pH values lower than 4.5 showed aluminium contents higher than 2.0 mg/l. 66.7% of the specimens within the pH-range 4.5 to 5.0 and 20% of the specimens within the pH-range 5.0 to 5.5 had aluminium levels of more than 0.2 mg/l, that is the maximum permissible limit value of the drinking water regulation. High contents of aluminium in drinking water are objectionable from the hygienic point of view, as they may cause intoxications in infants and patients with impaired renal function. In addition to this, the involvement of aluminium in the pathogenesis of severe degenerative disorders of the central nervous system cannot be excluded, such as Alzheimers disease, amyotrophic lateral sclerosis and Parkinsons dementia.

  1. Electrostatic precipitator

    SciTech Connect

    Hayashi, T.

    1982-08-03

    An electrostatic precipitator comprising a plurality of flat plate dust-collecting electrodes, arranged in substantially equally spaced and parallel relationship with one another and each having a discharge electrode, or electrodes, on and along the edge of one side thereof with the discharge electrodes of the adjacent dust-collecting electrodes alternately facing in opposite directions; the edges having the discharge electrodes are arranged in a setback relation by some distance in relation to the nearby edges of the adjacent dust-collecting plates, where no discharge electrodes are provided, so that uniform and nonuniform electric fields may be produced.

  2. Parametric Flutter Analysis of the TCA Configuration and Recommendation for FFM Design and Scaling

    NASA Technical Reports Server (NTRS)

    Baker, Myles; Lenkey, Peter

    1997-01-01

    The current HSR Aeroelasticity plan to design, build, and test a full span, free flying transonic flutter model in the TDT has many technical obstacles that must be overcome for a successful program. One technical obstacle is the determination of a suitable configuration and point in the sky to use in setting the scaling point for the ASE models program. Determining this configuration and point in the sky requires balancing several conflicting requirements, including model buildability, tunnel test safety, and the ability of the model to represent the flutter mechanisms of interest. As will be discussed in detail in subsequent sections, the current TCA design exhibits several flutter mechanisms of interest. It has been decided that the ASE models program will focus on the low frequency symmetric flutter mechanism, and will make no attempt to investigate high frequency flutter mechanisms. There are several reasons for this choice. First, it is believed that the high frequency flutter mechanisms are similar in nature to classical wing bending/torsion flutter, and therefore there is more confidence that this mechanism can be predicted using current techniques. The low frequency mode, on the other hand, is a highly coupled mechanism involving wing, body, tail, and engine motion which may be very difficult to predict. Second, the high frequency flutter modes result in very small weight penalties (several hundred pounds), while suppression of the low frequency mechanism inside the flight envelope causes thousands of pounds to be added to the structure. In order to successfully test the low frequency flutter mode of interest, a suitable starting configuration and point in the sky must be identified. The configuration and point in the sky must result in a wind tunnel model that (1) represents the low-frequency wing/body/engine/empennage flutter mechanisms that are unique to HSCT configurations, (2) flutters at an acceptably low frequency in the tunnel, (3) flutters at an

  3. Photocatalytic removal of 2,4-dichlorophenoxyacetic acid herbicide on copper oxide/titanium dioxide prepared by co-precipitation method

    NASA Astrophysics Data System (ADS)

    Lee, Shu Chin; Hasan, Norhasnita; Lintang, Hendrik O.; Shamsuddin, Mustaffa; Yuliati, Leny

    2016-02-01

    In this work, suppression of the charge recombination on the titanium dioxide (TiO2) was reported by the addition of copper oxide (CuO), which led to a higher activity of TiO2 for removal of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide. A series of CuO/TiO2 with CuO loadings of 0.1-1 wt% was prepared through a co-precipitation method. X-ray diffraction patterns revealed that the presence of CuO could not be detected as the low loading amount of CuO might have good dispersion on the surface of TiO2. Diffuse reflectance UV-visible spectra suggested that low loading amount of CuO did not influence the optical property of TiO2. Fluorescence spectroscopy revealed that TiO2 possessed a dominant emission peak of 407 nm at an excitation wavelength of 218 nm. The increasing loading amount of CuO decreased the emission intensity of TiO2, suggesting the successful reduction of charge recombination. After irradiation under UV light for 1 h, CuO(0.1 wt%)/TiO2 gave the highest percentage removal of the herbicide among the samples. The optimum loading amount of CuOmight improve the charge separation and reduce the electron-hole recombination on TiO2 without blocking the active sites, thus leading to the improved photocatalytic activity. This work showed that CuO/TiO2 is a potential photocatalyst for environmental remediation.

  4. Formation of stratospheric nitric acid by a hydrated ion cluster reaction: chemical and dynamical effects of energetic particle precipitation on the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Kvissel, O. K.; Orsolini, Y. J.; Stordal, F.

    2012-04-01

    In order to Improve our understanding of the effects of energetic particle precipitation upon the nitrogen family (NOy) and ozone (O3), we have modelled the chemical and dynamical middle atmosphere response to the introduction of a chemical pathway that produces nitric acid (HNO3) by conversion of dinitrogen pentoxide (N2O5) upon hydrated water clusters H+•(H2O)n. We have used an ensemble of simulations with the National Center for Atmospheric Research (NCAR) Whole-Atmosphere Community Climate Model (WACCM) chemistry-climate model. The introduced chemical pathway alters the internal partitioning of NOy during winter months in both hemispheres, and ultimately triggers statistically significant changes in the climatological distributions of constituents including: i) a cold season production of HNO3 with a corresponding loss of N2O5, and ii) a cold season decrease in NOx/NOy-ratio and an increase of O3, in polar regions. We see an improved seasonal evolution of modelled HNO3 compared to satellite observations from Microwave Limb Sounder (MLS), albeit not enough HNO3 is produced at high altitudes. Through O3 changes, both temperature and dynamics are affected, allowing for complex chemical-dynamical feedbacks beyond the cold season when the introduced pathway is active. Hence, we also find a NOx polar increase in spring-to-summer in the SH, and in spring in the NH. The springtime NOx increase arises from anomalously strong poleward transport associated with a weaker polar vortex. In the southern hemisphere, a statistical significant weakening of the stratospheric jet is altered down to the lower stratosphere, and we argue that it is caused by strengthened planetary waves induced by mid-latitude zonal asymmetries in O3 and short-wave heating.

  5. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast

    PubMed Central

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF. PMID:27630630

  6. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast.

    PubMed

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF. PMID:27630630

  7. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast

    PubMed Central

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF.

  8. Self-nanoemulsifying drug delivery system of trans-cinnamic acid: formulation development and pharmacodynamic evaluation in alloxan-induced type 2 diabetic rat model.

    PubMed

    Wang, Houyong; Li, Qiang; Deng, Wenwen; Omari-Siaw, E; Wang, Qilong; Wang, Shicheng; Wang, Shengli; Cao, Xia; Xu, Ximing; Yu, Jiangnan

    2015-03-01

    The objective of this study was to formulate a self-nanoemulsifying oral drug delivery system (SNEDDS) for the poorly water-soluble trans-Cinnamic acid (t-CA SNEDDS) that could be evaluated for its antihyperglycemic efficacy in comparison to the parent t-CA in an alloxan-induced diabetic rat model. A SNEDDS formulation consisting of 60% surfactant (Kolliphor EL), 10% co-surfactant (PEG 400) and 30% oil (isopropyl myristate) proved to be optimal. t-CA SNEDDS (80 mg/kg, p.o.), t-CA suspension (80 mg/kg, p.o.), and Metformin Hydrochloride Tablets (230 mg/kg, p.o.) were administer qdfor 30 days to diabetic rats. After treatment the body weight of diabetic rats was increased, blood glucose levels, total cholesterol, and triglyceride in the serum tended to be normalized, while the levels of alanine aminotransferase and aspartate aminotransferase were markedly decreased. The effects of t-CA SNEDDS were superior to that of the t-CA suspension. The present study demonstrated that t-CA was effective in attenuating the effects of alloxan treatment and that t-CA SNEDDS with a more favorable absorption and enhanced bioavailability is more effective than t-CA.

  9. Citric acid as the last therapeutic approach in an acute life-threatening metabolic decompensation of propionic acidaemia.

    PubMed

    Siekmeyer, Manuela; Petzold-Quinque, Stefanie; Terpe, Friederike; Beblo, Skadi; Gebhardt, Rolf; Schlensog-Schuster, Franziska; Kiess, Wieland; Siekmeyer, Werner

    2013-01-01

    The tricarboxylic acid (TCA) cycle represents the key enzymatic steps in cellular energy metabolism. Once the TCA cycle is impaired in case of inherited metabolic disorders, life-threatening episodes of metabolic decompensation and severe organ failure can arise. We present the case of a 6 ½-year-old girl with propionic acidaemia during an episode of acute life-threatening metabolic decompensation and severe lactic acidosis. Citric acid given as an oral formulation showed the potential to sustain the TCA cycle flux. This therapeutic approach may become a treatment option in a situation of acute metabolic crisis, possibly preventing severe disturbance of energy metabolism.

  10. The Role of TCA Cycle Anaplerosis in Ketosis and Fatty Liver in Periparturient Dairy Cows

    PubMed Central

    White, Heather M.

    2015-01-01

    The transition to lactation period in dairy cattle is characterized by metabolic challenges, negative energy balance, and adipose tissue mobilization. Metabolism of mobilized adipose tissue is part of the adaptive response to negative energy balance in dairy cattle; however, the capacity of the liver to completely oxidize nonesterified fatty acids may be limited and is reflective of oxaloacetate pool, the carbon carrier of the tricarboxylic acid cycle. Alternative metabolic fates of acetyl-CoA from nonesterified fatty acids include esterification to triacylglycerides and ketogenesis, and when excessive, these pathways lead to fatty liver and ketosis. Examination of the anaplerotic and cataplerotic pull of oxaloacetate by the tricarboxylic acid cycle and gluconeogenesis may provide insight into the balance of oxidation and esterification of acetyl-CoA within the liver of periparturient dairy cows. PMID:26479386

  11. The Role of TCA Cycle Anaplerosis in Ketosis and Fatty Liver in Periparturient Dairy Cows.

    PubMed

    White, Heather M

    2015-08-18

    The transition to lactation period in dairy cattle is characterized by metabolic challenges, negative energy balance, and adipose tissue mobilization. Metabolism of mobilized adipose tissue is part of the adaptive response to negative energy balance in dairy cattle; however, the capacity of the liver to completely oxidize nonesterified fatty acids may be limited and is reflective of oxaloacetate pool, the carbon carrier of the tricarboxylic acid cycle. Alternative metabolic fates of acetyl-CoA from nonesterified fatty acids include esterification to triacylglycerides and ketogenesis, and when excessive, these pathways lead to fatty liver and ketosis. Examination of the anaplerotic and cataplerotic pull of oxaloacetate by the tricarboxylic acid cycle and gluconeogenesis may provide insight into the balance of oxidation and esterification of acetyl-CoA within the liver of periparturient dairy cows.

  12. DISSOLUTION OF PLUTONIUM CONTAINING CARRIER PRECIPITATE BY CARBONATE METATHESIS AND SEPARATION OF SULFIDE IMPURITIES THEREFROM BY SULFIDE PRECIPITATION

    DOEpatents

    Duffield, R.B.

    1959-07-14

    A process is described for recovering plutonium from foreign products wherein a carrier precipitate of lanthanum fluoride containing plutonium is obtained and includes the steps of dissolving the carrier precipitate in an alkali metal carbonate solution, adding a soluble sulfide, separating the sulfide precipitate, adding an alkali metal hydroxide, separating the resulting precipitate, washing, and dissolving in a strong acid.

  13. Quantification of PEGylated proteases with varying degree of conjugation in mixtures: An analytical protocol combining protein precipitation and capillary gel electrophoresis.

    PubMed

    Morgenstern, Josefine; Busch, Markus; Baumann, Pascal; Hubbuch, Jürgen

    2016-09-01

    PEGylation, i.e. the covalent attachment of chemically activated polyethylene glycol (PEG) to proteins, is a technique commonly used in biopharmaceutical industry to improve protein stability, pharmacokinetics and resistance to proteolytic degradation. Therefore, PEGylation represents a valuable strategy to reduce autocatalysis of biopharmaceutical relevant proteases during production, purification and storage. In case of non-specific random conjugation the existence of more than one accessible binding site results in conjugates which vary in position and number of attached PEG molecules. These conjugates may differ considerably in their physicochemical properties. Optimizing the reaction conditions with respect to the degree of PEGylation (number of linked PEG molecules) using high-throughput screening (HTS) technologies requires a fast and reliable analytical method which allows stopping the reaction at defined times. In this study an analytical protocol for PEGylated proteases is proposed combining preservation of sample composition by trichloroacetic acid (TCA) precipitation with high-throughput capillary gel electrophoresis (HT-CGE). The well-studied protein hen egg-white lysozyme served as a model system for validating the newly developed analytical protocol for 10kDa mPEG-aldehyde conjugates. PEGamer species were purified by chromatographic separation for calibrating the HT-CGE system. In a case study, the serine protease Savinase(®) which is highly sensitive to autocatalysis was randomly modified with 5kDa and 10kDa mPEG-aldehyde and analyzed. Using the presented TCA protocol baseline separation between PEGamer species was achieved allowing for the analysis of heterogeneous PEGamer mixtures while preventing protease autocatalysis. PMID:27521256

  14. Quantification of PEGylated proteases with varying degree of conjugation in mixtures: An analytical protocol combining protein precipitation and capillary gel electrophoresis.

    PubMed

    Morgenstern, Josefine; Busch, Markus; Baumann, Pascal; Hubbuch, Jürgen

    2016-09-01

    PEGylation, i.e. the covalent attachment of chemically activated polyethylene glycol (PEG) to proteins, is a technique commonly used in biopharmaceutical industry to improve protein stability, pharmacokinetics and resistance to proteolytic degradation. Therefore, PEGylation represents a valuable strategy to reduce autocatalysis of biopharmaceutical relevant proteases during production, purification and storage. In case of non-specific random conjugation the existence of more than one accessible binding site results in conjugates which vary in position and number of attached PEG molecules. These conjugates may differ considerably in their physicochemical properties. Optimizing the reaction conditions with respect to the degree of PEGylation (number of linked PEG molecules) using high-throughput screening (HTS) technologies requires a fast and reliable analytical method which allows stopping the reaction at defined times. In this study an analytical protocol for PEGylated proteases is proposed combining preservation of sample composition by trichloroacetic acid (TCA) precipitation with high-throughput capillary gel electrophoresis (HT-CGE). The well-studied protein hen egg-white lysozyme served as a model system for validating the newly developed analytical protocol for 10kDa mPEG-aldehyde conjugates. PEGamer species were purified by chromatographic separation for calibrating the HT-CGE system. In a case study, the serine protease Savinase(®) which is highly sensitive to autocatalysis was randomly modified with 5kDa and 10kDa mPEG-aldehyde and analyzed. Using the presented TCA protocol baseline separation between PEGamer species was achieved allowing for the analysis of heterogeneous PEGamer mixtures while preventing protease autocatalysis.

  15. Aluminum colloid formation and its effect on co-precipitation of zinc during acid rock drainage remediation with clinoptilolite in a slurry bubble column

    NASA Astrophysics Data System (ADS)

    Xu, W.; Li, L. Y.; Grace, J. R.

    2012-04-01

    Zinc and other metal ions were adsorbed in a laboratory slurry bubble column (SBC) by natural clinoptilolite sorbent particles. During the remediation process, significant white precipitates were sometimes observed. Both zinc and aluminum were detected in the colloidal mixtures. It is shown that Al leached from clinoptilolite during the agitation, contributing to the precipitate. As a result of the Al leaching and increase of pH during the remediation process, the formation of an Al colloid and zinc adsorption onto it could significantly improve ARD remediation, given the high adsorption capacity of the colloid. Sorption of cations increased with increasing colloid formation. Various conditions were tested to investigate their impact on (a) dealumination of clinoptilolite; (b) Al hydrolysis/colloid formation; and (c) adsorption onto the colloidal mixture. The test results indicate that dealumination contributes to the excess aluminum in the aqueous phase and to precipitates. The excess dealumination varies with pH and agitation time. Al hydrolysis occurs with increasing pH due to the neutralization effect of clinoptilolite. A significant proportion of zinc adsorbed onto the collectible aluminum precipitates.

  16. ROCK inhibitor Y-27632 inhibits the growth, migration, and invasion of Tca8113 and CAL-27 cells in tongue squamous cell carcinoma.

    PubMed

    Wang, Zhi-Ming; Yang, Dong-Sheng; Liu, Jie; Liu, Hong-Bo; Ye, Ming; Zhang, Yu-Fei

    2016-03-01

    The objective of this study is to determine the effects of Rho-associated coiled-coil containing protein kinase (ROCK) inhibitor Y-27632 on the growth, invasion, and migration of Tca8113 and CAL-27 cells in tongue squamous cell carcinoma (TSCC). The methods of the study are as follows: After being routinely cultured for 24 h, Tca8113 and CAL-27 cells were treated with Y-27632 solution. The morphological change of Y-27632-treated cells was observed under an optical microscope and an inverted microscope; MTT assay was performed to measure the optical density (OD) of cells and calculate cell growth inhibition rate; the change of apoptosis was detected by AnnexinV-FITC/PI assay; cell invasion and migration were measured by Transwell assay. The results were as follows: (1) With increasing concentration of Y-27632, cell morphology changed and cell apoptosis appeared; (2) MTT assay showed that inhibition effect of Y-27632 on Tca8113 and CAL-27 cells was enhanced with increasing concentrations and time (all P < 0.01); (3) Apoptosis showed that, compared with controls, the number of apoptosis cells in experimental groups was significantly increased (all P < 0.01). Apoptosis rate was elevated with increasing concentrations of Y-27632; (4) Transwell assay showed, after a treatment with Y-27632, the number of migrated and invaded Tca8113 and CAL-27 cells in each group was statistically different (all P < 0.01); compared with controls, the number of migrated cell in groups treated with Y-27632 was decreased and less Tca8113 and CAL-27 cells in experimental groups passed through polycarbonate membrane (all P < 0.05). The study concludes that Y-27632 can inhibit the growth, invasion, and migration of Tca8113 and CAL-27 cells, suggesting that Y-27632 may be therapeutically useful in TSCC.

  17. Electrostatic precipitator manual

    SciTech Connect

    McDonald, J.R.; Dean, A.H.

    1982-01-01

    Studies performed by various individuals and organizations on the application of electrostatic precipitators to the collection of fly ash produced in the combustion of pulverized fuel are summarized in this manual. The scope of the studies evaluated include full scale precipitators and laboratory investigations. It covers measurement of fly ash resistivity, rapping reentrainment, conditioning agents, fundamental operations of hot-side precipitators. The major chapter headings are: Terminology and General Design Features Associated with Electrostatic Precipitators Used to Collect Fly Ash Particles; Fundamental Principles of Electrostatic Precipitation; Limiting Factors Affecting Precipitator Performance; Use of Electrostatic Precipitators for the Collection of Fly Ash; Analysis of Factors influencing ESP Performance; Emissions from Electrostatic Precipitators; Choosig an Electrostatic Precipitator: Cold-side versus Hot-side; Safety Aspects of Working with Electrostatic Precipitators; Maintenance Procedures; Troubleshooting; An Electrostatic Precipitator Computer Model; Features of a Well-equipped Electrostatic Precipitator.

  18. Aircraft Emission Scenarios Projected in Year 2015 for the NASA Technology Concept Aircraft (TCA) High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Baughcum, Steven L.; Henderson, Stephen C.

    1998-01-01

    This report describes the development of a three-dimensional database of aircraft fuel burn and emissions (fuel burned, NOx, CO, and hydrocarbons) from projected fleets of high speed civil transports (HSCTs) on a universal airline network. Inventories for 500 and 1000 HSCT fleets, as well as the concurrent subsonic fleets, were calculated. The HSCT scenarios are calculated using the NASA technology concept airplane (TCA) and update an earlier report. These emissions inventories are available for use by atmospheric scientists conducting the Atmospheric Effects of Stratospheric Aircraft (AESA) modeling studies. Fuel burned and emissions of nitrogen oxides (NOx as NO2), carbon monoxide, and hydrocarbons have been calculated on a 1 degree latitude x 1 degree longitude x 1 kilometer pressure altitude grid and delivered to NASA as electronic files.

  19. Resistance to vanadium in Pseudomonas fluorescens ATCC 17400 caused by mutations in TCA cycle enzymes.

    PubMed

    Denayer, Sarah; Matthijs, Sandra; Cornelis, Pierre

    2006-11-01

    Vanadium inhibits the growth of Pseudomonas fluorescens ATCC 17400 in the low-iron casamino acids medium and even more when iron is added to the medium. Analysis of transposon mutants allowed the isolation of two mutants with increased resistance to vanadium. One mutant had an insertion in the idh gene coding for the tricarboxylic acid enzyme isocitrate dehydrogenase. The second mutant had the transposon inserted into acnD, one out of three genes coding for a 2-methyl-isocitrate dehydratase (aconitase). In this mutant, there was a higher level of acnB aconitase transcripts while the levels of acnA transcripts were unchanged. A nonpolar idh mutant was obtained, which showed the same level of resistance against vanadium as the original transposon mutant. PMID:17020548

  20. Evolution and functional implications of the tricarboxylic acid cycle as revealed by phylogenetic analysis.

    PubMed

    Cavalcanti, João Henrique Frota; Esteves-Ferreira, Alberto A; Quinhones, Carla G S; Pereira-Lima, Italo A; Nunes-Nesi, Adriano; Fernie, Alisdair R; Araújo, Wagner L

    2014-10-01

    The tricarboxylic acid (TCA) cycle, a crucial component of respiratory metabolism, is composed of a set of eight enzymes present in the mitochondrial matrix. However, most of the TCA cycle enzymes are encoded in the nucleus in higher eukaryotes. In addition, evidence has accumulated demonstrating that nuclear genes were acquired from the mitochondrial genome during the course of evolution. For this reason, we here analyzed the evolutionary history of all TCA cycle enzymes in attempt to better understand the origin of these nuclear-encoded proteins. Our results indicate that prior to endosymbiotic events the TCA cycle seemed to operate only as isolated steps in both the host (eubacterial cell) and mitochondria (alphaproteobacteria). The origin of isoforms present in different cell compartments might be associated either with gene-transfer events which did not result in proper targeting of the protein to mitochondrion or with duplication events. Further in silico analyses allow us to suggest new insights into the possible roles of TCA cycle enzymes in different tissues. Finally, we performed coexpression analysis using mitochondrial TCA cycle genes revealing close connections among these genes most likely related to the higher efficiency of oxidative phosphorylation in this specialized organelle. Moreover, these analyses allowed us to identify further candidate genes which might be used for metabolic engineering purposes given the importance of the TCA cycle during development and/or stress situations.

  1. Evolution and Functional Implications of the Tricarboxylic Acid Cycle as Revealed by Phylogenetic Analysis

    PubMed Central

    Cavalcanti, João Henrique Frota; Esteves-Ferreira, Alberto A.; Quinhones, Carla G.S.; Pereira-Lima, Italo A.; Nunes-Nesi, Adriano; Fernie, Alisdair R.; Araújo, Wagner L.

    2014-01-01

    The tricarboxylic acid (TCA) cycle, a crucial component of respiratory metabolism, is composed of a set of eight enzymes present in the mitochondrial matrix. However, most of the TCA cycle enzymes are encoded in the nucleus in higher eukaryotes. In addition, evidence has accumulated demonstrating that nuclear genes were acquired from the mitochondrial genome during the course of evolution. For this reason, we here analyzed the evolutionary history of all TCA cycle enzymes in attempt to better understand the origin of these nuclear-encoded proteins. Our results indicate that prior to endosymbiotic events the TCA cycle seemed to operate only as isolated steps in both the host (eubacterial cell) and mitochondria (alphaproteobacteria). The origin of isoforms present in different cell compartments might be associated either with gene-transfer events which did not result in proper targeting of the protein to mitochondrion or with duplication events. Further in silico analyses allow us to suggest new insights into the possible roles of TCA cycle enzymes in different tissues. Finally, we performed coexpression analysis using mitochondrial TCA cycle genes revealing close connections among these genes most likely related to the higher efficiency of oxidative phosphorylation in this specialized organelle. Moreover, these analyses allowed us to identify further candidate genes which might be used for metabolic engineering purposes given the importance of the TCA cycle during development and/or stress situations. PMID:25274566

  2. [Reductive dechlorination of trichloroacetic acid by bioelectrochemically catalytic method].

    PubMed

    Li, Yu-Ping; Cao, Hong-Bin; Zhang, Yi

    2005-07-01

    Direct electrochemical behaviors of hemoglobin (Hb) immobilized on carbon nanotube (CNT) modified carbon paste electrode with adsorption were investigated. Cyclic voltammetry of Hb-CNT-modified electrode showed a pair of well-defined and nearly reversible peaks for HbhemeFe(III) /Fe(II) redox couple in pH = 7 PBS buffers. The electrocatalytic behaviors of Hb-CNT-modified electrode for the reductive dechlorination of trichloroacetic acid (TCA) were studied by cyclic voltammmetry and fixed-potential electrolysis technique, and the reductive mechanism of TCA was discussed by analysis of reduction products. The results showed that Hb-CNT-modified electrode possessed good electro-catalytic activity for reduction of TCA and the dechlorination of TCA was stepwise, following the pathway of trichloroacetic--> dichloroacetic--> monochloroacetic--> acetic. The dechlorination of TCA in waster water was investigated using a two-compartment flow reactor with working electrode compartment packed with Hb-CNT-modified graphite electrode. The conversion of TCA was 40.13% with electrolysis for 180 min at - 0.60V (vs. SCE).

  3. Pharmacokinetic modeling of trichloroethylene and trichloroacetic acid in humans.

    PubMed

    Allen, B C; Fisher, J W

    1993-02-01

    The development and application of appropriate physiologically based pharmacokinetic (PBPK) models of chemical contaminants will provide a rational basis for risk assessment extrapolation. Trichloroethylene (TCE) is a widespread contaminant found in soil, groundwater, and the atmosphere. Exposures to TCE and its metabolites have been found to be carcinogenic in rodents. In this study, a PBPK model for TCE and its major metabolite, trichloroacetic acid (TCA), is developed for humans. The model parameters, estimated from the relevant published literature on human exposures to TCE and its metabolites, are described. Key parameters describing the metabolism of TCE and the kinetics of TCA were estimated by optimization. The optimization was accomplished by simultaneously matching model predictions to observations of TCE concentrations in blood and exhaled breath, TCA plasma concentrations, and urinary TCA excretion from five published studies. The optimized human PBPK model provides an excellent description of TCE and TCA kinetics. The predictions were especially good for TCA plasma concentrations following repeated TCE inhalation, an exposure scenario similar to that occurring in the workplace. The human PBPK model can be used to estimate dose metrics resulting from TCE exposures and is therefore useful when considering the estimation of human health risks associated with such exposures.

  4. Mechanisms by which acid precipitation produces embryonic death in aquatic vertebrates. Technical completion report, 1 May 1977-31 December 1980

    SciTech Connect

    Pough, F.H.

    1981-03-01

    Fourteen species of amphibians show a general similarity in their tolerance of acid media during embryonic development. More than 85% mortality is produced by pHs of 3.7 to 3.9 and more than 50% mortality occurs at pHs of 4.0 or less. Similar values have been reported for fishes. The sensitivity of amphibian embryos to acidity is greater in late stages of their development than it is during the initial cleavage of the embryos. The teratogenic effects of acidity appear to be the result of damage to the superficial tissues of the embryo. A similar response occurs in fish embryos. Because of the similarity of sensitivity and response to acidity of fishes and amphibians, the latter animals are suitable experimental models for investigations of the details of acid resistance. Controlled breedings of African clawed frogs (Xenopus laevis) indicated that the offspring of some pairs of parents were more resistant to acidity than those of other pairs. Wild populations of spotted salamanders (Ambystoma maculatum) breeding in some ponds in the Ithaca, New York, region have probably been exposed to increasingly acid conditions for the past three decades (10 or more generations). In the most acid ponds more than 70% of the embryos die before hatching. Despite the intensity and duration of this selection, it was not possible to demonstrate any difference in sensitivity to acidity between eggs collected from acidic and neutral breeding sites.

  5. Uncertainty of Prebiotic Scenarios: The Case of the Non-Enzymatic Reverse Tricarboxylic Acid Cycle

    NASA Astrophysics Data System (ADS)

    Zubarev, Dmitry Yu; Rappoport, Dmitrij; Aspuru-Guzik, Alán

    2015-01-01

    We consider the hypothesis of the primordial nature of the non-enzymatic reverse tricarboxylic acid (rTCA) cycle and describe a modeling approach to quantify the uncertainty of this hypothesis due to the combinatorial aspect of the constituent chemical transformations. Our results suggest that a) rTCA cycle belongs to a degenerate optimum of auto-catalytic cycles, and b) the set of targets for investigations of the origin of the common metabolic core should be significantly extended.

  6. Research on the variability of physico-chemical parameters characterising acid precipitation at the Jeziory Ecological Station in the Wielkopolski National Park (Poland).

    PubMed

    Walna, B; Siepak, J

    1999-10-01

    Here the water quality of precipitation at the Adam Mickiewicz University Ecological station is presented for the period 1992-1997 to examine one of the main factors causing the degradation of the natural environment of the Weilkopolski National Park. In the course of daily observations the amount of rainfall, its electrical conductivity and pH were measured. As much as 61% of the tested precipitation had a pH < 4.6, and 92% had a pH < 5.6; some very low pH values, even below 3.0, were occasionally observed. The annual volume-weighted average pH during the full period was 4.28 and the lowest yearly average was 3.92 (1994). The chemical composition of precipitation showed the dominance of sulphate and calcium ions. Fluoride ions also contributed significantly to the anion charge. There were also small amounts of heavy metals and polycyclic aromatic hydrocarbons. A chemical analysis of throughfall showed a considerably increased concentration of some ions, in particular potassium.

  7. Hydrocarbonates in precipitation of Moscow

    NASA Astrophysics Data System (ADS)

    Larin, Igor; Eremina, Iren; Aloyan, Artash; Arutunan, Vardan; Chubarova, Natalia; Yermakov, Alexandr

    2016-04-01

    According to monitoring of the atmospheric precipitation of Moscow a number of episodes is revealed, the content of hydrocarbonates in which repeatedly surpasses equilibrium level. Facts of their registration are linked to complex structure of precipitation which is caused by a different chemical composition of condensation nucleus. As a result on the underlying surface two groups of drops with acidity of the different nature are transferred. The acidity of the first, "metal" group of droplets, is determined by a carbonate equilibrium with atmospheric CO2 and with dissolved carbonates of alkali and alkaline earth metals. The acidity of the second, "ammonium" group droplets, is characterized by the balance between an ammonia absorbed from the air and atmospheric acids. Regulation of acidity of the deposits measured in a course of monitoring, occurs for this reason not only in the air, but also in the condensate receiver. A mixing "metal" and "ammonium" groups precipitation accompanied by only a partial transfer of hydrocarbonates in the dissolved CO2. The process is braked as a result of a practical stop of exit of CO2 into the atmosphere because of a mass transfer deceleration. In turn it leads to excess of equilibrium level of hydrocarbonates in the receiver. Estimates show that the acidity of "ammonia" component of precipitation should be much higher than the reported monitoring data. In other words, real acidity of rain drops can essentially exceed that is measured by standard procedures of monitoring of deposits, that it is necessary to take into consideration at calculations of so-called critical levels of acid loading on people and environment. In other words, the actual acidity of raindrops could greatly exceed that is measured by the standard procedures for monitoring rainfall, which should be taken into account when calculating the so-called critical levels of acid loads on people and the environment. It follows that the true level of hazard of acid rain

  8. Metabolic engineering in the biotechnological production of organic acids in the tricarboxylic acid cycle of microorganisms: Advances and prospects.

    PubMed

    Yin, Xian; Li, Jianghua; Shin, Hyun-Dong; Du, Guocheng; Liu, Long; Chen, Jian

    2015-11-01

    Organic acids, which are chemically synthesized, are also natural intermediates in the metabolic pathways of microorganisms, among which the tricarboxylic acid (TCA) cycle is the most crucial route existing in almost all living organisms. Organic acids in the TCA cycle include citric acid, α-ketoglutaric acid, succinic acid, fumaric acid, l-malic acid, and oxaloacetate, which are building-block chemicals with wide applications and huge markets. In this review, we summarize the synthesis pathways of these organic acids and review recent advances in metabolic engineering strategies that enhance organic acid production. We also propose further improvements for the production of organic acids with systems and synthetic biology-guided metabolic engineering strategies.

  9. PRECIPITATION OF PLUTONOUS PEROXIDE

    DOEpatents

    Barrick, J.G.; Manion, J.P.

    1961-08-15

    A precipitation process for recovering plutonium values contained in an aqueous solution is described. In the process for precipitating plutonium as plutonous peroxide, hydroxylamine or hydrazine is added to the plutoniumcontaining solution prior to the addition of peroxide to precipitate plutonium. The addition of hydroxylamine or hydrazine increases the amount of plutonium precipitated as plutonous peroxide. (AEC)

  10. Bile acids regulate intestinal cell proliferation by modulating EGFR and FXR signaling.

    PubMed

    Dossa, Avafia Y; Escobar, Oswaldo; Golden, Jamie; Frey, Mark R; Ford, Henri R; Gayer, Christopher P

    2016-01-15

    Bile acids (BAs) are synthesized in the liver and secreted into the intestine. In the lumen, enteric bacteria metabolize BAs from conjugated, primary forms into more toxic unconjugated, secondary metabolites. Secondary BAs can be injurious to the intestine and may contribute to disease. The epidermal growth factor receptor (EGFR) and the nuclear farnesoid X receptor (FXR) are known to interact with BAs. In this study we examined the effects of BAs on intestinal epithelial cell proliferation and investigated the possible roles for EGFR and FXR in these effects. We report that taurine-conjugated cholic acid (TCA) induced proliferation, while its unconjugated secondary counterpart deoxycholic acid (DCA) inhibited proliferation. TCA stimulated phosphorylation of Src, EGFR, and ERK 1/2. Pharmacological blockade of any of these pathways or genetic ablation of EGFR abrogated TCA-stimulated proliferation. Interestingly, Src or EGFR inhibitors eliminated TCA-induced phosphorylation of both molecules, suggesting that their activation is interdependent. In contrast to TCA, DCA exposure diminished EGFR phosphorylation, and pharmacological or siRNA blockade of FXR abolished DCA-induced inhibition of proliferation. Taken together, these results suggest that TCA induces intestinal cell proliferation via Src, EGFR, and ERK activation. In contrast, DCA inhibits proliferation via an FXR-dependent mechanism that may include downstream inactivation of the EGFR/Src/ERK pathway. Since elevated secondary BA levels are the result of specific bacterial modification, this may provide a mechanism through which an altered microbiota contributes to normal or abnormal intestinal epithelial cell proliferation.

  11. Species differences in hepatobiliary disposition of taurocholic acid in human and rat sandwich-cultured hepatocytes: implications for drug-induced liver injury.

    PubMed

    Yang, Kyunghee; Pfeifer, Nathan D; Köck, Kathleen; Brouwer, Kim L R

    2015-05-01

    The bile salt export pump (BSEP) plays an important role in bile acid excretion. Impaired BSEP function may result in liver injury. Bile acids also undergo basolateral efflux, but the relative contributions of biliary (CLBile) versus basolateral efflux (CLBL) clearance to hepatocellular bile acid excretion have not been determined. In the present study, taurocholic acid (TCA; a model bile acid) disposition was characterized in human and rat sandwich-cultured hepatocytes (SCH) combined with pharmacokinetic modeling. In human SCH, biliary excretion of TCA predominated (CLBile = 0.14 ± 0.04 ml/min per g liver; CLBL = 0.042 ± 0.019 ml/min per g liver), whereas CLBile and CLBL contributed approximately equally to TCA hepatocellular excretion in rat SCH (CLBile = 0.34 ± 0.07 ml/min per g liver; CLBL = 0.26 ± 0.07 ml/min per g liver). Troglitazone decreased TCA uptake, CLBile, and CLBL; membrane vesicle assays revealed for the first time that the major metabolite, troglitazone sulfate, was a noncompetitive inhibitor of multidrug resistance-associated protein 4, a basolateral bile acid efflux transporter. Simulations revealed that decreased CLBile led to a greater increase in hepatic TCA exposure in human than in rat SCH. A decrease in both excretory pathways (CLBile and CLBL) exponentially increased hepatic TCA in both species, suggesting that 1) drugs that inhibit both pathways may have a greater risk for hepatotoxicity, and 2) impaired function of an alternate excretory pathway may predispose patients to hepatotoxicity when drugs that inhibit one pathway are administered. Simulations confirmed the protective role of uptake inhibition, suggesting that a drug's inhibitory effects on bile acid uptake also should be considered when evaluating hepatotoxic potential. Overall, the current study precisely characterized basolateral efflux of TCA, revealed species differences in hepatocellular TCA efflux pathways, and provided insights about altered hepatic bile acid exposure

  12. Acid rain

    SciTech Connect

    Not Available

    1985-01-01

    This report has four parts: they discuss acid rain in relation to acid soils, agriculture, forests, and aquatic ecosystems. Among findings: modern sources of acid deposition from the atmosphere for all the acid soils in the world, nor even chiefly responsible for those of northern U.S. Agriculture has its problems, but acid precipitation is probably not one of them. More research is needed to determine to what extent acid precipitation is responsible for forest declines and for smaller detrimental effects on forest growth where no damage to the foliage is evident. Many lakes and streams are extremely sensitive to added acids.

  13. Acid precipitation: effects on fresh-water ecosystems. January 1978-September 1988 (Citations from the Life Sciences Collection data base). Report for January 1978-September 1988

    SciTech Connect

    Not Available

    1988-10-01

    This bibliography contains citations concerning the effects of acidification of fresh-water ecosystems. Algae and diatom distribution, survival, and reproduction rates of specific fish species under acid-lake conditions, and tolerance to stress caused by acidic conditions in fresh water ecosystems are studied. Effects of water ph on trace metal toxicity to fresh water organisms is briefly considered. Control and reduction of acidification is excluded from this bibliography. (Contains 290 citations fully indexed and including a title list.)

  14. Acid Rain.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  15. The role of surface chemical analysis in a study to select replacement processes for TCA vapor degreasing

    NASA Technical Reports Server (NTRS)

    Lesley, Michael W.; Davis, Lawrence E.; Moulder, John F.; Carlson, Brad A.

    1995-01-01

    The role of surface-sensitive chemical analysis (ESCA, AES, and SIMS) in a study to select a process to replace 1, 1, 1-trichloroethane (TCA) vapor degreasing as a steel and aluminum bonding surface preparation method is described. The effort was primarily concerned with spray-in-air cleaning processes involving aqueous alkaline and semi-aqueous cleaners and a contamination sensitive epoxy-to-metal bondline. While all five cleaners tested produced bonding strength results equal to or better than those produced by vapor degreasing, the aqueous alkaline cleaners yielded results which were superior to those produced by the semi-aqueous cleaners. The main reason for the enhanced performance appears to be a silicate layer left behind by the aqueous alkaline cleaners. The silicate layer increases the polarity of the surface and enhances epoxy-to-metal bonding. On the other hand, one of the semi-aqueous cleaners left a nonpolar carbonaceous residue which appeared to have a negative effect on epoxy-to-metal bonding. Differences in cleaning efficiency between cleaners/processes were also identified. These differences in surface chemistry, which were sufficient to affect bonding, were not detected by conventional chemical analysis techniques.

  16. The CMS fast beams condition monitor back-end electronics based on MicroTCA technology: status and development

    NASA Astrophysics Data System (ADS)

    Zagozdzinska, Agnieszka A.; Dabrowski, Anne E.; Pozniak, Krzysztof T.

    2015-09-01

    The Fast Beams Condition Monitor (BCM1F), upgraded for LHC Run II, is used to measure the online luminosity and machine induced background for the CMS experiment. The detector consists of 24 single-crystal CVD diamond sensors that are read out with a custom fast front-end chip fabricated in 130 nm CMOS technology. Since the signals from the sensors are used for real time monitoring of the LHC conditions they are processed by dedicated back-end electronics to measure separately rates corresponding to LHC collision products, machine induced background and residual activation exploiting different arrival times. The system is built in MicroTCA technology and uses high speed analog-to-digital converters. In operational modes of high rates, consecutive events, spaced in time by less than 12.5 ns, may cause partially overlapping events. Hence, novel signal processing techniques are deployed to resolve overlapping peaks. The high accuracy qualification of the signals is crucial to determine the luminosity and the machine induced background rates for the CMS experiment and the LHC.

  17. Mitochondria-translocated phosphoglycerate kinase 1 functions as a protein kinase to coordinate glycolysis and TCA cycle in tumorigenesis

    PubMed Central

    Li, Xinjian; Jiang, Yuhui; Meisenhelder, Jill; Yang, Weiwei; Hawke, David H.; Zheng, Yanhua; Xia, Yan; Aldape, Kenneth; He, Jie; Hunter, Tony; Wang, Liwei; Lu, Zhimin

    2016-01-01

    SUMMARY It is unclear how the Warburg effect that exemplifies enhanced glycolysis in the cytosol is coordinated with suppressed mitochondrial pyruvate metabolism. We demonstrate here that hypoxia, EGFR activation, and expression of K-Ras G12V and B-Raf V600E induce mitochondrial translocation of phosphoglycerate kinase 1 (PGK1); this is mediated by ERK-dependent PGK1 S203 phosphorylation and subsequent PIN1-mediated cis–trans isomerization. Mitochondrial PGK1 acts as a protein kinase to phosphorylate pyruvate dehydrogenase kinase 1 (PDHK1) at T338, which activates PDHK1 to phosphorylate and inhibit the pyruvate dehydrogenase (PDH) complex. This reduces mitochondrial pyruvate utilization, suppresses reactive oxygen species production, increases lactate production, and promotes brain tumorigenesis. Furthermore, PGK1 S203 and PDHK1 T338 phosphorylation levels correlate with PDH S293 inactivating phosphorylation levels and poor prognosis in glioblastoma patients. This work highlights that PGK1 act as a protein kinase in coordinating glycolysis and the TCA cycle, which is instrumental in cancer metabolism and tumorigenesis. PMID:26942675

  18. Trichloroacetic acid fate and toxicity to the macrophytes Myriophyllum spicatum and Myriophyllum sibiricum under field conditions.

    PubMed

    Hanson, Mark L; Sibley, Paul K; Ellis, David A; Fineberg, Neil A; Mabury, Scott A; Solomon, Keith R; Muir, Derek C

    2002-03-01

    Trichloroacetic acid (TCA) has been detected in rain, snow, and river samples throughout the world. It may enter into natural water systems via herbicide use, as a by-product of water disinfection, from emissions of spent bleach liquor of kraft pulp mills, and as a natural fungal product. This compound is phytotoxic and likely to accumulate in aquatic environments. A study to assess the fate of TCA in semi-natural aquatic environments and the toxicity of TCA to rooted aquatic macrophytes was conducted. The experiment involved exposing three replicate 12000 l aquatic microcosms at the University of Guelph Microcosm Facility to 0.05, 0.5, 3, and 10 mg/l of TCA for 35 days in a one-way analysis of variance design. Each microcosm was stocked with 14 individual 5 cm apical shoots of Myriophyllum spicatum and M. sibiricum. The plants were sampled at regular intervals and assessed for the somatic endpoints of plant length, root growth, number of nodes and wet and dry mass and the biochemical endpoints of chlorophyll-a and chlorophyll-b, carotenoid content, and citric acid levels. TCA half-lives in the microcosms ranged from 190 to 296 h depending on the initial concentration of TCA. Myriophyllum spp. results indicate that while there were some statistically significant differences from controls, there were no biologically significant effects of TCA for any of the endpoints examined. These data suggest that TCA does not pose a significant risk to these macrophytes up to 10 mg/l, which typically exceeds environmentally relevant concentrations by several orders of magnitude.

  19. Automated homogeneous oxalate precipitation of Pu(III)

    SciTech Connect

    Yarbro, S.L.; Schreiber, S.B.; Dunn, S.L.; Mills, C.W.

    1990-01-01

    Homogeneous oxalate precipitation using diethyl oxalate was compared to precipitating Pu(III) oxalate with solid oxalic acid. The diethyl oxalate technique at 75{degree}C is better because it gives 50% less plutonium in the filtrate with a reasonable filtering time. Also, the procedure for the homogeneous precipitation is easier to automate because the liquid diethyl oxalate is simpler to introduce into the precipitator than solid oxalic acid. It also provides flexibility because the hydrolysis rate and therefore the precipitation rate can be controlled by varying the temperature. 5 refs., 3 figs., 3 tabs.

  20. Recovery of Plutonium by Carrier Precipitation

    DOEpatents

    Goeckermann, R. H.

    1961-04-01

    The recovery of plutonium from an aqueous nitric acid Zr-containing solution of 0.2 to 1N acidity is accomplished by adding fluoride anions (1.5 to 5 mg/l), and precipitating the Pu with an excess of H/sub 2/0/sub 2/ at 53 to 65 deg C. (AEC)

  1. RECOVERY OF PLUTONIUM BY CARRIER PRECIPITATION

    DOEpatents

    Goeckermann, R.H.

    1961-04-01

    A process is given for recovering plutonium from an aqueous nitric acid zirconium-containing solution of an acidity between 0.2 and 1 N by adding fluoride anions (1.5 to 5 mg/l) and precipitating the plutonium with an excess of hydrogen peroxide at from 53 to 65 deg C.

  2. Comparison of Intact Arabidopsis thaliana Leaf Transcript Profiles during Treatment with Inhibitors of Mitochondrial Electron Transport and TCA Cycle

    PubMed Central

    Yu, Jianping; Ruckle, Michael E.; McIntosh, Lee; Hock, Jeffery J.; Bingham, Scott; White, Samuel J.; George, Rajani M.; Subbaiah, Chalivendra C.; Rhoads, David M.

    2012-01-01

    Plant mitochondria signal to the nucleus leading to altered transcription of nuclear genes by a process called mitochondrial retrograde regulation (MRR). MRR is implicated in metabolic homeostasis and responses to stress conditions. Mitochondrial reactive oxygen species (mtROS) are a MRR signaling component, but whether all MRR requires ROS is not established. Inhibition of the cytochrome respiratory pathway by antimycin A (AA) or the TCA cycle by monofluoroacetate (MFA), each of which initiates MRR, can increase ROS production in some plant cells. We found that for AA and MFA applied to leaves of soil-grown Arabidopsis thaliana plants, ROS production increased with AA, but not with MFA, allowing comparison of transcript profiles under different ROS conditions during MRR. Variation in transcript accumulation over time for eight nuclear encoded mitochondrial protein genes suggested operation of both common and distinct signaling pathways between the two treatments. Consequences of mitochondrial perturbations for the whole transcriptome were examined by microarray analyses. Expression of 1316 and 606 genes was altered by AA and MFA, respectively. A subset of genes was similarly affected by both treatments, including genes encoding photosynthesis-related proteins. MFA treatment resulted in more down-regulation. Functional gene category (MapMan) and cluster analyses showed that genes with expression levels affected by perturbation from AA or MFA inhibition were most similarly affected by biotic stresses such as pathogens. Overall, the data provide further evidence for the presence of mtROS-independent MRR signaling, and support the proposed involvement of MRR and mitochondrial function in plant responses to biotic stress. PMID:23028523

  3. The Effect of Walterinnesia aegyptia Venom Proteins on TCA Cycle Activity and Mitochondrial NAD+-Redox State in Cultured Human Fibroblasts

    PubMed Central

    Ghneim, Hazem K.; Al-Sheikh, Yazeed A.; Aboul-Soud, Mourad A. M.

    2015-01-01

    Fibroblast cultures were used to study the effects of crude Walterinnesia aegyptia venom and its F1–F7 protein fractions on TCA cycle enzyme activities and mitochondrial NAD-redox state. Confluent cells were incubated with 10 μg of venom proteins for 4 hours at 37°C. The activities of all studied TCA enzymes and the non-TCA mitochondrial NADP+-dependent isocitrate dehydrogenase underwent significant reductions of similar magnitude (50–60% of control activity) upon incubation of cells with the crude venom and fractions F4, F5, and F7 and 60–70% for fractions F3 and F6. In addition, the crude and fractions F3–F7 venom proteins caused a drop in mitochondrial NAD+ and NADP+ levels equivalent to around 25% of control values. Whereas the crude and fractions F4, F5, and F7 venom proteins caused similar magnitude drops in NADH and NADPH (around 55% of control levels), fractions F3 and F6 caused a more drastic drop (60–70% of control levels) of both reduced coenzymes. Results indicate that the effects of venom proteins could be directed at the mitochondrial level and/or the rates of NAD+ and NADP+ biosynthesis. PMID:25705684

  4. The effect of Walterinnesia aegyptia venom proteins on TCA cycle activity and mitochondrial NAD(+)-redox state in cultured human fibroblasts.

    PubMed

    Ghneim, Hazem K; Al-Sheikh, Yazeed A; Aboul-Soud, Mourad A M

    2015-01-01

    Fibroblast cultures were used to study the effects of crude Walterinnesia aegyptia venom and its F1-F7 protein fractions on TCA cycle enzyme activities and mitochondrial NAD-redox state. Confluent cells were incubated with 10 μg of venom proteins for 4 hours at 37°C. The activities of all studied TCA enzymes and the non-TCA mitochondrial NADP(+)-dependent isocitrate dehydrogenase underwent significant reductions of similar magnitude (50-60% of control activity) upon incubation of cells with the crude venom and fractions F4, F5, and F7 and 60-70% for fractions F3 and F6. In addition, the crude and fractions F3-F7 venom proteins caused a drop in mitochondrial NAD(+) and NADP(+) levels equivalent to around 25% of control values. Whereas the crude and fractions F4, F5, and F7 venom proteins caused similar magnitude drops in NADH and NADPH (around 55% of control levels), fractions F3 and F6 caused a more drastic drop (60-70% of control levels) of both reduced coenzymes. Results indicate that the effects of venom proteins could be directed at the mitochondrial level and/or the rates of NAD(+) and NADP(+) biosynthesis. PMID:25705684

  5. The effect of Walterinnesia aegyptia venom proteins on TCA cycle activity and mitochondrial NAD(+)-redox state in cultured human fibroblasts.

    PubMed

    Ghneim, Hazem K; Al-Sheikh, Yazeed A; Aboul-Soud, Mourad A M

    2015-01-01

    Fibroblast cultures were used to study the effects of crude Walterinnesia aegyptia venom and its F1-F7 protein fractions on TCA cycle enzyme activities and mitochondrial NAD-redox state. Confluent cells were incubated with 10 μg of venom proteins for 4 hours at 37°C. The activities of all studied TCA enzymes and the non-TCA mitochondrial NADP(+)-dependent isocitrate dehydrogenase underwent significant reductions of similar magnitude (50-60% of control activity) upon incubation of cells with the crude venom and fractions F4, F5, and F7 and 60-70% for fractions F3 and F6. In addition, the crude and fractions F3-F7 venom proteins caused a drop in mitochondrial NAD(+) and NADP(+) levels equivalent to around 25% of control values. Whereas the crude and fractions F4, F5, and F7 venom proteins caused similar magnitude drops in NADH and NADPH (around 55% of control levels), fractions F3 and F6 caused a more drastic drop (60-70% of control levels) of both reduced coenzymes. Results indicate that the effects of venom proteins could be directed at the mitochondrial level and/or the rates of NAD(+) and NADP(+) biosynthesis.

  6. Pu-erh tea has in vitro anticancer activity in TCA8113 cells and preventive effects on buccal mucosa cancer in U14 cells injected mice in vivo.

    PubMed

    Zhao, Xin; Qian, Yu; Zhou, Ya-Lin; Wang, Rui; Wang, Qiang; Li, Gui-Jie

    2014-01-01

    Pu-erh tea is a functional tea production in China. The functional effects should be proved. The oral cancer preventive and antimetastatic effects of Pu-erh tea in vitro and in vivo have been studied respectively. Pu-erh tea showed an inhibitory effect on human tongue carcinoma TCA8113 cells proliferation tested by 3-(4,5-Dimethyl-2-Thiazolyl)-2,5-Diphenyltetrazolium Bromide assay and induced TCA8113 apoptosis shown anticancer effect. The antimetastatic effect of Pu-erh tea in TCA8113 cells was proved by the decreasing of matrix metalloproteinases (MMPs) and increasing of tissue inhibitors of metalloproteinases (TIMPs) mRNA transcription. In the animal experiments, the tumor volumes and lymph node metastasis rates of Pu-erh tea-treated mice were smaller than control mice. Pu-erh tea reduced the levels of the serum proinflammatory cytokines interleukin (IL)-6, IL-12, tumor necrosis factor-α, and interferon-γ to a greater extent compared with the control mice, and the levels of 200 μg/mL treatment was more close to the normal mice than 100 μg/mL treated mice. Pu-erh tea also significantly induced apoptosis in tissues of mice (P < 0.05) by upregulating Bax and downregulating Bcl-2. These results demonstrate Pu-erh tea has cancer preventive and anti-metastatic effects on buccal mucosa cancer, the higher concentration get better efficiency.

  7. IMPROVED PROCESS OF PLUTONIUM CARRIER PRECIPITATION

    DOEpatents

    Faris, B.F.

    1959-06-30

    This patent relates to an improvement in the bismuth phosphate process for separating and recovering plutonium from neutron irradiated uranium, resulting in improved decontamination even without the use of scavenging precipitates in the by-product precipitation step and subsequently more complete recovery of the plutonium in the product precipitation step. This improvement is achieved by addition of fluomolybdic acid, or a water soluble fluomolybdate, such as the ammonium, sodium, or potassium salt thereof, to the aqueous nitric acid solution containing tetravalent plutonium ions and contaminating fission products, so as to establish a fluomolybdate ion concentration of about 0.05 M. The solution is then treated to form the bismuth phosphate plutonium carrying precipitate.

  8. Ames Optimized TCA Configuration

    NASA Technical Reports Server (NTRS)

    Cliff, Susan E.; Reuther, James J.; Hicks, Raymond M.

    1999-01-01

    Configuration design at Ames was carried out with the SYN87-SB (single block) Euler code using a 193 x 49 x 65 C-H grid. The Euler solver is coupled to the constrained (NPSOL) and the unconstrained (QNMDIF) optimization packages. Since the single block grid is able to model only wing-body configurations, the nacelle/diverter effects were included in the optimization process by SYN87's option to superimpose the nacelle/diverter interference pressures on the wing. These interference pressures were calculated using the AIRPLANE code. AIRPLANE is an Euler solver that uses a unstructured tetrahedral mesh and is capable of computations about arbitrary complete configurations. In addition, the buoyancy effects of the nacelle/diverters were also included in the design process by imposing the pressure field obtained during the design process onto the triangulated surfaces of the nacelle/diverter mesh generated by AIRPLANE. The interference pressures and nacelle buoyancy effects are added to the final forces after each flow field calculation. Full details of the (recently enhanced) ghost nacelle capability are given in a related talk. The pseudo nacelle corrections were greatly improved during this design cycle. During the Ref H and Cycle 1 design activities, the nacelles were only translated and pitched. In the cycle 2 design effort the nacelles can translate vertically, and pitch to accommodate the changes in the lower surface geometry. The diverter heights (between their leading and trailing edges) were modified during design as the shape of the lower wing changed, with the drag of the diverter changing accordingly. Both adjoint and finite difference gradients were used during optimization. The adjoint-based gradients were found to give good direction in the design space for configurations near the starting point, but as the design approached a minimum, the finite difference gradients were found to be more accurate. Use of finite difference gradients was limited by the CPU time limit available on the Cray machines. A typical optimization run using finite difference gradients can use only 30 to 40 design variables and one optimization iteration within the 8 hour queue limit for the chosen grid size and convergence level. The efficiency afforded by the adjoint method allowed for 50-120 design variables and 5-10 optimization iterations in the 8 hour queue. Geometric perturbations to the wing and fuselage were made using the Hicks/Henne (HH) shape functions. The HH functions were distributed uniformly along the chords of the wing defining sections and lofted linearly. During single-surface design, constraints on thickness and volume at selected wing stations were imposed. Both fuselage camber and cross-sectional area distributions were permitted to change during design. The major disadvantage to the use of these functions is the inherent surface waviness produced by repeated use of such functions. Many smoothing operations were required following optimization runs to produce a configuration with reasonable smoothness. Wagner functions were also used on the wing sections but were never used on the fuselage. The Wagner functions are a family of increasingly oscillatory functions that have also been used extensively in airfoil design. The leading and trailing edge regions of the wing were designed by use of polynomial and monomial functions respectively. Twist was attempted but was abandoned because of little performance improvement available from changing the baseline twist.

  9. Formation of stratospheric nitric acid by a hydrated ion cluster reaction: Implications for the effect of energetic particle precipitation on the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Kvissel, O.-K.; Orsolini, Y. J.; Stordal, F.; Isaksen, I. S. A.; Santee, M. L.

    2012-08-01

    In order to improve our understanding of the effects of energetic particle precipitation on the middle atmosphere and in particular upon the nitrogen family and ozone, we have modeled the chemical and dynamical middle atmosphere response to the introduction of a chemical pathway that produces HNO3 by conversion of N2O5 upon hydrated water clusters H+·(H2O)n. We have used an ensemble of simulations with the National Center for Atmospheric Research (NCAR) Whole-Atmosphere Community Climate Model (WACCM) chemistry-climate model. The chemical pathway alters the internal partitioning of the NOy family during winter months in both hemispheres, and ultimately triggers statistically significant changes in the climatological distributions of constituents including: i) a cold season production and loss of HNO3 and N2O5, respectively, and ii) a cold season decrease and increase in NOx/NOy-ratio and O3, respectively, in the polar regions of both hemispheres. We see an improved seasonal evolution of modeled HNO3 compared to satellite observations from Microwave Limb Sounder (MLS), albeit not enough HNO3 is produced at high altitudes. Through O3changes, both temperature and dynamics are affected, allowing for complex chemical-dynamical feedbacks beyond the cold season when the pathway is active. Hence, we also find a NOxpolar increase in spring-to-summer in the southern hemisphere, and in spring in the northern hemisphere. The springtime NOxincrease arises from anomalously strong poleward transport associated with a weaker polar vortex. We argue that the weakening of zonal-mean polar winds down to the lower stratosphere, which is statistically significant at the 0.90 level in spring months in the southern hemisphere, is caused by strengthened planetary waves induced by the middle and sub-polar latitude zonal asymmetries in O3and short-wave heating.

  10. Input of trichloroacetic acid into the vegetation of various climate zones--measurements on several continents.

    PubMed

    Weissflog, Ludwig; Krüger, Gert; Elansky, Nikolai; Putz, Erich; Pfennigsdorff, Andrea; Seyfarth, Klaus Ullrich; Nüchter, Matthias; Lange, Christian; Kotte, Karsten

    2003-07-01

    Trichloroacetic acid (TCA, CCl(3)COOH) is a phytotoxic chemical. Although TCA salts and derivates were once used as herbicides to combat perennial grasses and weeds, they have since been banned because of their indiscriminate herbicidal effects on woody plant species. However, TCA can also be formed in the atmosphere. For instance, the high-volatile C(2)-chlorohydrocarbons tetrachloroethene (TECE, C(2)Cl(4)) and 1,1,1-trichloroethane (TCE, CCl(3)CH(3)) can react under oxidative conditions in the atmosphere to form TCA and other substances. The ongoing industrialisation of Southeast Asia, South Africa and South America means that use of TECE as solvents in the metal and textile industries of these regions in the southern hemisphere can be expected to rise. The increasing emissions of this substance--together with the rise in the atmospheric oxidation potential caused by urban activities, slash and burn agriculture and forest fires in the southern hemisphere--could lead to a greater input/formation of TCA in the vegetation located in the lee of these emission sources. By means of biomonitoring studies, the input/formation of TCA in vegetation was detected at various locations in South America, North America, Africa, and Europe. PMID:12738268

  11. Effects of trichloroacetic acid on the nitrogen metabolism of Pinus sylvestris--a 13C/15N tracer study.

    PubMed

    Hafner, Christoph; Jung, Klaus; Schüürmann, Gerrit

    2002-01-01

    Trichloroacetic acid (TCA) can be found in various environmental compartments like air, rain and plants all over the world. It is assumed that TCA is an atmospheric degradation product of volatile chloroorganic hydrocarbons. The herbicide effect of TCA in higher concentrations is well known, but not much is known about the phytotoxic effects in environmentally relevant concentrations. It can be shown in this study by using the 13C/15N stable isotope tracer technique that [13C]TCA is taken up by roots of two-year-old seedlings of Pinus sylvestris L. and transported into the needles. At the same time the effect of the substance on nitrogen metabolism can be analyzed by measuring the incorporation of 15NO3- into different nitrogen fractions of the plant. The more [13C]TCA incorporation, the higher the synthesis of 15N labelled amino acids and proteins is. These effects on the nitrogen metabolism are probably based on the activation of stress- and detoxification metabolism. It has to be assumed that there is an influence on N metabolism of Pinus sylvestris caused by the deposition of environmentally relevant TCA concentrations.

  12. The use of dielectric spectroscopy for the characterisation of the precipitation of hydrophobically modified poly(acrylic-acid) with divalent barium ions.

    PubMed

    Christensen, Peter Vittrup; Keiding, Kristian

    2009-12-01

    The use of dielectric spectroscopy as a monitor for coagulation processes was investigated. Hydrophobically modified poly(acrylic-acid) polymers were used as model macromolecules and coagulated with barium ions. The coagulation process was quantified using a photometric dispersion analyser, thereby serving as a point of reference for the dielectric spectroscopy. It was found that the hydrophobic modification increased the dosage of barium needed to obtain complete coagulation, whereas the dosage required to initiate coagulation was lowered. The coagulation of the polymer samples caused the relaxation time of the measured dielectric dispersion to increase, and this parameter was found to be a good indicator of the formation of polymer aggregates. The magnitude of the dielectric dispersion decreased as a function of barium dosage, but when coagulation was initiated an increase was observed. The observed agreement between the onset of coagulation and the changes in the dielectric dispersion shows the potential use of dielectric spectroscopy for the characterisation of coagulation processes. PMID:19751938

  13. Acid-precipitation studies in Colorado and Wyoming: Interim report of surveys of Montane amphibians and water chemistry. Interim report, 1986-1988

    SciTech Connect

    Corn, P.S.; Stolzenburg, W.; Bury, R.B.

    1989-06-01

    Surveys for amphibians were conducted in the Rocky Mountains of northern Colorado and southern Wyoming from 1986 to 1988. The northern leopard frog (Rana pipiens) was present at only 12% of historically known localities, and the boreal toad (Bufo boreas) was present at 17% of known localities. Chorus frogs (Pseudacris triseriata) suffered a catastrophic decline in population size in one population monitored since 1961, but regionally, this species was observed in 64% of known localities. Tiger salamanders (Ambystoma tigrinum) and wood frogs (Rana sylvatica) were present at 45% and 69% of known localities respectively. Acid neutralizing capacity, pH, specific conductivity, and cation concentrations in water at amphibian localities were negatively correlated with elevation. Survival of wood frog embryos declined when exposed to aluminum concentrations.

  14. Distribution, thickness, and volume of fine-grained sediment from precipitation of metals from acid-mine waters in Keswick Reservoir, Shasta County, California

    USGS Publications Warehouse

    Bruns, Terry R.; Alpers, Charles N.; Carlson, Paul

    2006-01-01

    In February 1993, the U.S. Geological Survey (USGS) acquired high-resolution seismic-reflection data to map the distribution and thickness of fine-grained sediments associated with acid-mine drainage in Keswick Reservoir on the Sacramento River, near Redding, California. In the Spring Creek Arm of Keswick Reservoir, the sediments occurred in three distinct accumulations; thicknesses are greater than 2 meters (m) in the western accumulation, greater than 5 m in the central accumulation, and up to 8 m in the eastern accumulation. In Keswick Reservoir, fine-grained sediments related to acid-mine drainage were present from slightly north of the Spring Creek Arm downstream to the Keswick Dam. Sediment thickness varies from about 3 m opposite the mouth of the Spring Creek Arm to less than 1 m near Keswick Dam. Our estimate for the total volume of fine-grained sediments in the Spring Creek Arm at the time of the geophysical survey in February 1993 is about 152,000 cubic meters in three sediment accumulations, with about 14,000, 32,000, and 105,000 cubic meters respectively in the western, central, and eastern accumulations. We interpreted that an additional 110, 000 cubic meters of material was present in the main part of Keswick Reservoir. At the time of data collection, we therefore estimate that the total volume of fine-grained sediment was 260,000 cubic meters. In the main part of Keswick Reservoir, 42% to 50% of the reservoir area contiguous to Spring Creek Arm had mappable fine-grained sediments. Decreasing sediment supply down-reservoir meant that mappable sediment covered only about 35% of the reservoir in the area to the south, decreasing to about 12% near Keswick Dam. Much of the reservoir bottom below the Spring Creek Arm could have had a thin (less than 20-30 cm) cover of fine-grained sediment that was not mappable using the seismic-reflection data.

  15. Global Precipitation Measurement

    NASA Technical Reports Server (NTRS)

    Hou, Arthur Y.; Skofronick-Jackson, Gail; Kummerow, Christian D.; Shepherd, James Marshall

    2008-01-01

    This chapter begins with a brief history and background of microwave precipitation sensors, with a discussion of the sensitivity of both passive and active instruments, to trace the evolution of satellite-based rainfall techniques from an era of inference to an era of physical measurement. Next, the highly successful Tropical Rainfall Measuring Mission will be described, followed by the goals and plans for the Global Precipitation Measurement (GPM) Mission and the status of precipitation retrieval algorithm development. The chapter concludes with a summary of the need for space-based precipitation measurement, current technological capabilities, near-term algorithm advancements and anticipated new sciences and societal benefits in the GPM era.

  16. Selective Precipitation of Proteins.

    PubMed

    Matulis, Daumantas

    2016-01-01

    Selective precipitation of proteins can be used as a bulk method to recover the majority of proteins from a crude lysate, as a selective method to fractionate a subset of proteins from a protein solution, or as a very specific method to recover a single protein of interest from a purification step. This unit describes a number of methods suitable for selective precipitation. In each of the protocols that are outlined, the physical or chemical basis of the precipitation process, the parameters that can be varied for optimization, and the basic steps for developing an optimized precipitation are described.

  17. Influence of acid and alkaline sources on optical, structural and photovoltaic properties of CdSe nanoparticles precipitated from aqueous solution

    NASA Astrophysics Data System (ADS)

    Coria-Monroy, C. Selene; Sotelo-Lerma, Mérida; Hu, Hailin

    2016-06-01

    CdSe is a widely researched material for photovoltaic applications. One of the most important parameters of the synthesis is the pH value, since it determines the kinetics and the mechanism of the reaction and in consequence, the optical and morphological properties of the products. We present the synthesis of CdSe in solution with strict control of pH and the comparison of ammonia and KOH as alkaline sources and diluted HCl as acid medium. CdSe formation was monitored with photoluminescence emission spectra (main peak in 490 nm, bandgap of CdSe nanoparticles). XRD patterns indicated that CdSe nanoparticles are mainly of cubic structure for ammonia and HCl, but the hexagonal planes appear with KOH. Product yield decreases with pH and also decreases with KOH at constant pH value since ammonia has a double function, as complexing agent and alkaline source. Changes in morphology were observed in SEM images as well with the different alkaline source. The effect of alkaline sources on photovoltaic performance of hybrid organic solar cells with CdSe and poly(3-hexylthiophene) as active layers was clearly observed, indicating the importance of synthesis conditions on optoelectronic properties of promising semiconductor nanomaterials for solar cell applications.

  18. Electrostatic precipitator efficiency enhancement

    SciTech Connect

    Polizzotti, D.M.; Steelhammer, J.C.

    1983-05-24

    Method for enhancing the removal of particles from a particleladen gas stream utilizing an electrostatic precipitator, which comprises treating the gas with morpholine or derivatives thereof. Treated particles are found to also have desirable flow characteristics. Particularly effective compositions for the purpose comprise a combination of the morpholine, or derivative thereof, with an electrostatic precipitator efficiency enhancer, and in particular an alkanolamine.

  19. Genome-wide screen identifies Escherichia coli TCA cycle-related mutants with extended chronological lifespan dependent on acetate metabolism and the hypoxia-inducible transcription factor ArcA

    PubMed Central

    Gonidakis, Stavros; Finkel, Steven E.; Longo, Valter D.

    2010-01-01

    Summary Single-gene mutants with extended lifespan have been described in several model organisms. We performed a genome-wide screen for long-lived mutants in Escherichia coli which revealed strains lacking TCA cycle-related genes that exhibit longer stationary phase survival and increased resistance to heat stress compared to wild-type. Extended lifespan in the sdhA mutant, lacking subunit A of succinate dehydrogenase, is associated with reduced production of superoxide and increased stress resistance. On the other hand, the longer lifespan of the lipoic acid synthase mutant (lipA) is associated with reduced oxygen consumption and requires the acetate-producing enzyme pyruvate oxidase, as well as acetyl-CoA synthetase, the enzyme that converts extracellular acetate to acetyl-CoA. The hypoxia-inducible transcription factor ArcA, acting independently of acetate metabolism, is also required for maximum lifespan extension in the lipA and lpdA mutants, indicating that these mutations promote entry into a mode normally associated with a low-oxygen environment. Since analogous changes from respiration to fermentation have been observed in long-lived Saccharomyces cerevisiae and Caenorhabditis elegans strains, such metabolic alterations may represent an evolutionarily conserved strategy to extend lifespan. PMID:20707865

  20. CCR7 ligands, SLC/6Ckine/Exodus2/TCA4 and CKbeta-11/MIP-3beta/ELC, are chemoattractants for CD56(+)CD16(-) NK cells and late stage lymphoid progenitors.

    PubMed

    Kim, C H; Pelus, L M; Appelbaum, E; Johanson, K; Anzai, N; Broxmeyer, H E

    1999-05-01

    Two human CC chemokines, SLC/6Ckine/Exodus2/TCA4 and CKbeta-11/MIP-3beta/ELC, are previously reported as efficacious chemoattractants for T- and B-cells and dendritic cells. SLC and CKbeta-11 share only 32% amino acid identity, but are ligands for the same chemokine receptor, CCR7. In this study, we examined chemotactic activity of SLC and CKbeta-11 for NK cells and lymphoid progenitors in bone marrow and thymus. It was found that these two CCR7 ligands are chemoattractants for neonatal cord blood and adult peripheral blood NK cells and cell lines. SLC and CKbeta-11 preferentially attract the CD56(+)CD16(-) NK cell subset over CD56(+)CD16(+) NK cells. SLC and CKbeta-11 also demonstrate selective chemotactic activity on late stage CD34(-)CD19(+)IgM- B-cell progenitors and CD4(+) and CD8(+) single-positive thymocytes, but not early stage progenitors. It was noted that SLC is an efficient desensitizer of CKbeta-11-dependent NK cell chemotaxis, while CKbeta-11 is a weak desensitizer of SLC-dependent chemotaxis. Taken together, these results suggest that SLC and CKbeta-11 have the potential to control trafficking of NK cell subsets and late stage lymphoid progenitors in bone marrow and thymus.

  1. [Chemical characteristics of atmospheric precipitation in Shenzhen].

    PubMed

    Niu, Yu-wen; He, Ling-yan; Hu, Min

    2008-04-01

    The precipitation chemical components are good indicators of the air pollution. With rapid economic developing, air quality has greatly changed in Shenzhen. To investigate Chemical feature of precipitation and atmospheric pollution characteristics in Shenzhen, two-year precipitation samples in Shenzhen were collected and analyzed. Based on the dataset, chemical characteristics of rainwater in Shenzhen were discussed. Results show that the concentration of the sum of anions and rations in Shenzhen rainwater was lower compared to northern cities like Beijing, whereas the acidification of rainwater was very serious in Shenzhen. Volume-weighted mean pH values of rainwater were 4.48 and 4.68 respectively, and 88% and 91% of rain events were acidic in 2004 and 2005, respectively. The contribution of SO4(2-) to Shenzhen rainwater acidity was smaller than that in northern cities and NO3- and Cl- played an important part to acidification of Shenzhen precipitation. The contribution of Cl- and Na+ to rainwater chemical components was higher, indicating the significant marine influence on Shenzhen precipitation. The secondary components like SO4(2-), NO3- and NH4+ contributed significantly to total ions of rainwater and they accounted for more than 40% of total ions in 2004 and 2005, which indicated the severe secondary pollution in Shenzhen. There was the obvious difference in origins for different rainwater components. Cl-, K+ and Na+ were mainly from marine contribution while SO4(2-), NO3-, Ca2+ and Mg2+ were mainly from non-sea salt fraction. Formic acid, acetic acid and oxalic acid were most abundant low-molecular weight organic acids and the sum of their concentrations accounted for 94% and 99% of total organic acids determined in 2004 and 2005, respectively.

  2. Comparison of efficacy of chemical peeling with 25% trichloroacetic acid and 0.1% retinoic acid for facial rejuvenation

    PubMed Central

    Gurel, Mehmet Salih; Gungor, Sule; Tekeli, Omur; Canat, Dilek

    2016-01-01

    Introduction Skin aging is a problem which negatively affects the psyche of the person, social relations, as well as work life and health and which compels the patients to find appropriate treatment methods. Numerous treatment methods have been developed in order to delay aging and to reduce the aging effects in addition to having a younger, healthier and more beautiful facial appearance. Aim To compare the efficiency, cosmetic results and possible adverse effects of the peeling treatment with 25% trichloroacetic acid (TCA) and 0.1% retinoic acid for facial rejuvenation in patients presenting with skin aging. Material and methods Fifty female patients in total presenting with medium and advanced degree skin aging were subject to this study. Two separate treatment groups were formed; the first group underwent chemical skin treatment with 25% TCA while the other group was applied with 0.1% retinoic acid treatment. Following the 4 months’ treatment the patients were controlled three times in total for post lesional hypopigmentation, hyperpigmentation, scars, skin irritation and other possible changes per month. The pretreatment and first follow-up visit, and final control images were comparatively evaluated by three observers via specific software. Results The healing rates of the group subject to retinoic acid were statistically higher (p < 0.05) compared to patients in the TCA group in the final follow-up visit following the treatment according to the first and second observers. On the other hand, according to the third observer, patients applied with retinoic acid presented with higher healing rates compared to those treated with TCA, however; this rate was not statistically significant (p > 0.05). The frequency of TCA- and retinoic acid-associated adverse effects was similar in both groups (p > 0.05). As a result of both treatments, a reduction in the quality of life scores as well as a pronounced recovery (p = 0.001) in the quality of life of those patients

  3. Acid rains over semi-urban atmosphere at eastern Himalaya and near coast of Bay of Bengal and alkaline rains over typical urban atmosphere in India: A study on precipitation chemistry during monsoon, 2013

    NASA Astrophysics Data System (ADS)

    Roy, Arindam; Chatterjee, Abhijit; Sarkar, Chirantan; Ghosh, Sanjay; Raha, Sibaji

    A study has been made on precipitation chemistry over three different atmosphere in India. Rain samples were collected during the entire period of monsoon (June-October) in the year of 2013 over Kolkata (22.6 (°) N, 89.4 (°) E), a mega city with typical urban atmosphere; Falta (22.3 (°) N, 88.1 (°) E), a rural atmosphere near eastern coast of Bay of Bengal and Darjeeling (27.01 (°) N, 88.15 (°) E), a high altitude (2200 m asl)hill station over eastern Himalaya in India. The major focus of the study is to investigate the composition of various types of aerosol ionic components scavenged and its effect on the acidity and how it differs between these three distinctly different atmospheres. The results showed that the sea-salt components were higher in Falta (140 mueqv/lit) followed by Kolkata (120 mueqv/lit) and minimum in Darjeeling (30 mueqv/lit). Over all the stations, Na (+) and Cl (-) showed strong correlations indicating common marine source. The marine air masses originated from Bay of Bengal (BoB) were found to significantly enrich sea-salt particles over Falta, the nearest station from BoB and having least effect on Darjeeling, the farthest station from BoB. Dust and anthropogenic aerosols particles were significantly higher over Kolkata compared to other two stations. Dust particles were found to scavenge more in the initial phase of monsoon and it gradually decreased as the monsoon progressed. The average pH of rain water over Kolkata was 6.0 indicating alkaline in nature. pH over Falta was 5.2 indicating slightly acidic in nature and the most important fact is that pH over Darjeeling was 4.6 indicating highly acidic in nature. It was found that Ca (2+) , Mg (2+) and NH _{4} (+) neutralized the acidity of rain water over all the stations with the maximum neutralizing factor for Ca (2+) . However, NH _{4} (+) played important role over Darjeeling in neutralizing rain water acidity. The major reason for high acidity of rain water was not due to high

  4. Lipotoxicity in steatohepatitis occurs despite an increase in tricarboxylic acid cycle activity.

    PubMed

    Patterson, Rainey E; Kalavalapalli, Srilaxmi; Williams, Caroline M; Nautiyal, Manisha; Mathew, Justin T; Martinez, Janie; Reinhard, Mary K; McDougall, Danielle J; Rocca, James R; Yost, Richard A; Cusi, Kenneth; Garrett, Timothy J; Sunny, Nishanth E

    2016-04-01

    The hepatic tricarboxylic acid (TCA) cycle is central to integrating macronutrient metabolism and is closely coupled to cellular respiration, free radical generation, and inflammation. Oxidative flux through the TCA cycle is induced during hepatic insulin resistance, in mice and humans with simple steatosis, reflecting early compensatory remodeling of mitochondrial energetics. We hypothesized that progressive severity of hepatic insulin resistance and the onset of nonalcoholic steatohepatitis (NASH) would impair oxidative flux through the hepatic TCA cycle. Mice (C57/BL6) were fed a high-trans-fat high-fructose diet (TFD) for 8 wk to induce simple steatosis and NASH by 24 wk. In vivo fasting hepatic mitochondrial fluxes were determined by(13)C-nuclear magnetic resonance (NMR)-based isotopomer analysis. Hepatic metabolic intermediates were quantified using mass spectrometry-based targeted metabolomics. Hepatic triglyceride accumulation and insulin resistance preceded alterations in mitochondrial metabolism, since TCA cycle fluxes remained normal during simple steatosis. However, mice with NASH had a twofold induction (P< 0.05) of mitochondrial fluxes (μmol/min) through the TCA cycle (2.6 ± 0.5 vs. 5.4 ± 0.6), anaplerosis (9.1 ± 1.2 vs. 16.9 ± 2.2), and pyruvate cycling (4.9 ± 1.0 vs. 11.1 ± 1.9) compared with their age-matched controls. Induction of the TCA cycle activity during NASH was concurrent with blunted ketogenesis and accumulation of hepatic diacylglycerols (DAGs), ceramides (Cer), and long-chain acylcarnitines, suggesting inefficient oxidation and disposal of excess free fatty acids (FFA). Sustained induction of mitochondrial TCA cycle failed to prevent accretion of "lipotoxic" metabolites in the liver and could hasten inflammation and the metabolic transition to NASH.

  5. Lipotoxicity in steatohepatitis occurs despite an increase in tricarboxylic acid cycle activity.

    PubMed

    Patterson, Rainey E; Kalavalapalli, Srilaxmi; Williams, Caroline M; Nautiyal, Manisha; Mathew, Justin T; Martinez, Janie; Reinhard, Mary K; McDougall, Danielle J; Rocca, James R; Yost, Richard A; Cusi, Kenneth; Garrett, Timothy J; Sunny, Nishanth E

    2016-04-01

    The hepatic tricarboxylic acid (TCA) cycle is central to integrating macronutrient metabolism and is closely coupled to cellular respiration, free radical generation, and inflammation. Oxidative flux through the TCA cycle is induced during hepatic insulin resistance, in mice and humans with simple steatosis, reflecting early compensatory remodeling of mitochondrial energetics. We hypothesized that progressive severity of hepatic insulin resistance and the onset of nonalcoholic steatohepatitis (NASH) would impair oxidative flux through the hepatic TCA cycle. Mice (C57/BL6) were fed a high-trans-fat high-fructose diet (TFD) for 8 wk to induce simple steatosis and NASH by 24 wk. In vivo fasting hepatic mitochondrial fluxes were determined by(13)C-nuclear magnetic resonance (NMR)-based isotopomer analysis. Hepatic metabolic intermediates were quantified using mass spectrometry-based targeted metabolomics. Hepatic triglyceride accumulation and insulin resistance preceded alterations in mitochondrial metabolism, since TCA cycle fluxes remained normal during simple steatosis. However, mice with NASH had a twofold induction (P< 0.05) of mitochondrial fluxes (μmol/min) through the TCA cycle (2.6 ± 0.5 vs. 5.4 ± 0.6), anaplerosis (9.1 ± 1.2 vs. 16.9 ± 2.2), and pyruvate cycling (4.9 ± 1.0 vs. 11.1 ± 1.9) compared with their age-matched controls. Induction of the TCA cycle activity during NASH was concurrent with blunted ketogenesis and accumulation of hepatic diacylglycerols (DAGs), ceramides (Cer), and long-chain acylcarnitines, suggesting inefficient oxidation and disposal of excess free fatty acids (FFA). Sustained induction of mitochondrial TCA cycle failed to prevent accretion of "lipotoxic" metabolites in the liver and could hasten inflammation and the metabolic transition to NASH. PMID:26814015

  6. Understanding Acid Rain

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  7. Ca2+-driven intestinal HCO(3)(-) secretion and CaCO3 precipitation in the European flounder in vivo: influences on acid-base regulation and blood gas transport.

    PubMed

    Cooper, Christopher A; Whittamore, Jonathan M; Wilson, Rod W

    2010-04-01

    Marine teleost fish continuously ingest seawater to prevent dehydration and their intestines absorb fluid by mechanisms linked to three separate driving forces: 1) cotransport of NaCl from the gut fluid; 2) bicarbonate (HCO(3)(-)) secretion and Cl(-) absorption via Cl(-)/HCO(3)(-) exchange fueled by metabolic CO(2); and 3) alkaline precipitation of Ca(2+) as insoluble CaCO(3), which aids H(2)O absorption). The latter two processes involve high rates of epithelial HCO(3)(-) secretion stimulated by intestinal Ca(2+) and can drive a major portion of water absorption. At higher salinities and ambient Ca(2+) concentrations the osmoregulatory role of intestinal HCO(3)(-) secretion is amplified, but this has repercussions for other physiological processes, in particular, respiratory gas transport (as it is fueled by metabolic CO(2)) and acid-base regulation (as intestinal cells must export H(+) into the blood to balance apical HCO(3)(-) secretion). The flounder intestine was perfused in vivo with salines containing 10, 40, or 90 mM Ca(2+). Increasing the luminal Ca(2+) concentration caused a large elevation in intestinal HCO(3)(-) production and excretion. Additionally, blood pH decreased (-0.13 pH units) and plasma partial pressure of CO(2) (Pco(2)) levels were elevated (+1.16 mmHg) at the highest Ca perfusate level after 3 days of perfusion. Increasing the perfusate [Ca(2+)] also produced proportional increases in net acid excretion via the gills. When the net intestinal flux of all ions across the intestine was calculated, there was a greater absorption of anions than cations. This missing cation flux was assumed to be protons, which vary with an almost 1:1 relationship with net acid excretion via the gill. This study illustrates the intimate link between intestinal HCO(3)(-) production and osmoregulation with acid-base balance and respiratory gas exchange and the specific controlling role of ingested Ca(2+) independent of any other ion or overall osmolality in marine

  8. Cloud and Precipitation Radar

    NASA Astrophysics Data System (ADS)

    Hagen, Martin; Höller, Hartmut; Schmidt, Kersten

    Precipitation or weather radar is an essential tool for research, diagnosis, and nowcasting of precipitation events like fronts or thunderstorms. Only with weather radar is it possible to gain insights into the three-dimensional structure of thunderstorms and to investigate processes like hail formation or tornado genesis. A number of different radar products are available to analyze the structure, dynamics and microphysics of precipitation systems. Cloud radars use short wavelengths to enable detection of small ice particles or cloud droplets. Their applications differ from weather radar as they are mostly orientated vertically, where different retrieval techniques can be applied.

  9. Extraction and Separation of Vitisin D, Ampelopsin B and cis-Vitisin A from Iris lactea Pall. var. chinensis (Fisch.) Koidz by Alkaline Extraction-Acid Precipitation and High-Speed Counter-Current Chromatography.

    PubMed

    Lv, Huanhuan; Zhou, Wenna; Wang, Xiaoyan; Wang, Zhenhua; Suo, Yourui; Wang, Honglun

    2016-01-01

    Naturally occurring oligostilbenes are receiving more attention because they exhibit several beneficial effects for health, including hepatoprotective, antitumor, anti-adipogenic, antioxidant, antiaging, anti-inflammatory, anti-microbial, antiviral, immunosuppressive and neuroprotective activities. Thus, they could be of some potentially therapeutic values for several diseases. In this study, we adopted the alkaline extraction-acid precipitation (AEAP) method for extraction of oligostilbenes from the seed kernel of Iris lactea Then, the high-speed counter-current chromatography (HSCCC) was used for preparative isolation and purification of oligostilbenes from the AEAP extracts. Finally, three oligostilbenes, namely vitisin D (73 mg), ampelopsin B (25 mg) and cis-vitisin A (16 mg), were successfully fractionated by HSCCC with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (2:5:3:6, v/v/v/v) from 300 mg of the AEAP extracts in ∼ 190 min. The purities of the three isolated oligostilbenes were all over 95.0% as analyzed by high performance liquid chromatography. They all were isolated from I. lacteal for the first time.The method of AEAP for the preparation of the oligostilbene-enriched crude sample was simple, and the HSCCC technique for the isolation and purification of oligostilbenes was efficient.

  10. Extraction and Separation of Vitisin D, Ampelopsin B and cis-Vitisin A from Iris lactea Pall. var. chinensis (Fisch.) Koidz by Alkaline Extraction-Acid Precipitation and High-Speed Counter-Current Chromatography.

    PubMed

    Lv, Huanhuan; Zhou, Wenna; Wang, Xiaoyan; Wang, Zhenhua; Suo, Yourui; Wang, Honglun

    2016-01-01

    Naturally occurring oligostilbenes are receiving more attention because they exhibit several beneficial effects for health, including hepatoprotective, antitumor, anti-adipogenic, antioxidant, antiaging, anti-inflammatory, anti-microbial, antiviral, immunosuppressive and neuroprotective activities. Thus, they could be of some potentially therapeutic values for several diseases. In this study, we adopted the alkaline extraction-acid precipitation (AEAP) method for extraction of oligostilbenes from the seed kernel of Iris lactea Then, the high-speed counter-current chromatography (HSCCC) was used for preparative isolation and purification of oligostilbenes from the AEAP extracts. Finally, three oligostilbenes, namely vitisin D (73 mg), ampelopsin B (25 mg) and cis-vitisin A (16 mg), were successfully fractionated by HSCCC with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (2:5:3:6, v/v/v/v) from 300 mg of the AEAP extracts in ∼ 190 min. The purities of the three isolated oligostilbenes were all over 95.0% as analyzed by high performance liquid chromatography. They all were isolated from I. lacteal for the first time.The method of AEAP for the preparation of the oligostilbene-enriched crude sample was simple, and the HSCCC technique for the isolation and purification of oligostilbenes was efficient. PMID:26847919

  11. Precipitation chemistry in central Amazonia

    NASA Astrophysics Data System (ADS)

    Andreae, M. O.; Talbot, R. W.; Berresheim, H.; Beecher, K. M.

    1990-09-01

    Rain samples from three sites in central Amazonia were collected over a period of 6 weeks during the 1987 wet season and analyzed for ionic species and dissolved organic carbon. A continuous record of precipitation chemistry and amount was obtained at two of these sites, which were free from local or regional pollution, for a time period of over 1 month. The volume-weighted mean concentrations of most species were found to be about a factor of 5 lower during the wet season compared with previous results from the dry season. Only sodium, potassium, and chloride showed similar concentrations in both seasons. When the seasonal difference in rainfall amount is taken into consideration, the deposition fluxes are only slightly lower for most species during the wet season than during the dry season, again with the exception of chloride, potassium, and sodium. Sodium and chloride are present in the same ratio as in sea salt; rapid advection of air masses of marine origin to the central Amazon Basin during the wet season may be responsible for the observed higher deposition flux of these species. Statistical analysis suggests that sulfate is, to a large extent, of marine (sea salt and biogenic) origin, but that long-range transport of combustion-derived aerosols also makes a significant contribution to sulfate and nitrate levels in Amazonian rain. Organic acid concentrations in rain were responsible for a large fraction of the observed precipitation acidity; their concentration was strongly influenced by gas/liquid interactions.

  12. Precipitation chemistry in central Amazonia

    NASA Technical Reports Server (NTRS)

    Andreae, M. O.; Talbot, R. W.; Berresheim, H.; Beecher, K. M.

    1990-01-01

    Rain samples from three sites in central Amazonia were collected over a period of 6 weeks during the 1987 wet season and analyzed for ionic species and dissolved organic carbon. A continuous record of precipitation chemistry and amount was obtained at two of these sites, which were free from local or regional pollution, for a time period of over 1 month. The volume-weighted mean concentrations of most species were found to be about a factor of 5 lower during the wet season compared with previous results from the dry season. Only sodium, potassium, and chloride showed similar concentrations in both seasons. When the seasonal difference in rainfall amount is taken into consideration, the deposition fluxes are only slightly lower for most species during the wet season than during the dry season, again with the exception of chloride, potassium, and sodium. Sodium and chloride are present in the same ratio as in sea salt; rapid advection of air masses of marine origin to the central Amazon Basin during the wet season may be responsible for the observed higher deposition flux of these species. Statistical analysis suggests that sulfate is, to a large extent, of marine (sea salt and biogenic) origin, but that long-range transport of combustion-derived aerosols also makes a significant contribution to sulfate and nitrate levels in Amazonian rain. Organic acid concentrations in rain were responsible for a large fraction of the observed precipitation acidity; their concentration was strongly influenced by gas/liquid interactions.

  13. IMERG Global Precipitation Rates

    NASA Video Gallery

    NASA's Global Precipitation Measurement mission has produced its first global map of rainfall and snowfall. The GPM Core Observatory launched one year ago on Feb. 27, 2014 as a collaboration betwee...

  14. My NASA Data Precipitation

    NASA Video Gallery

    This lesson has two activities that help students develop a basic understanding of the relationship between cloud type and the form of precipitation and the relationship between the amount of water...

  15. Precipitation Estimates for Hydroelectricity

    NASA Technical Reports Server (NTRS)

    Tapiador, Francisco J.; Hou, Arthur Y.; de Castro, Manuel; Checa, Ramiro; Cuartero, Fernando; Barros, Ana P.

    2011-01-01

    Hydroelectric plants require precise and timely estimates of rain, snow and other hydrometeors for operations. However, it is far from being a trivial task to measure and predict precipitation. This paper presents the linkages between precipitation science and hydroelectricity, and in doing so it provides insight into current research directions that are relevant for this renewable energy. Methods described include radars, disdrometers, satellites and numerical models. Two recent advances that have the potential of being highly beneficial for hydropower operations are featured: the Global Precipitation Measuring (GPM) mission, which represents an important leap forward in precipitation observations from space, and high performance computing (HPC) and grid technology, that allows building ensembles of numerical weather and climate models.

  16. Chemisorption And Precipitation Reactions

    EPA Science Inventory

    The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suit...

  17. Feasibility of preparing nanodrugs by high-gravity reactive precipitation.

    PubMed

    Chen, Jian-Feng; Zhou, Min-Yi; Shao, Lei; Wang, Yu-Yong; Yun, Jimmy; Chew, Nora Y K; Chan, Hak-Kim

    2004-01-01

    To study the feasibility of producing nanoparticles of organic pharmaceuticals using a novel high-gravity reactive precipitation (HGRP) technique, reactive precipitation of benzoic acid as a model compound was carried out in a rotating packed bed under high gravity. The main factors such as the rotating bed speed, concentration and volume flow rate of the reactants (sodium benzoate and HCl) affecting the particle size of the precipitate were studied. Particle size was measured by transmission electron microscopy. Benzoic acid was precipitated as nanoparticles as fine as 10nm. The particle size was decreased with increasing rotating bed speed, concentration and volume flow rate of the reactants. The formation of ultrafine particles was due to intensified micro-mixing of reactants in the rotating bed to enhance nucleation while suppressing crystal growth. The results have demonstrated the feasibility to produce nanodrugs by the principle of acid-base precipitating reaction using HGRP.

  18. Agreement between monthly precipitation estimates from TRMM satellite, NCEP reanalysis, and merged gauge-satellite analysis

    NASA Astrophysics Data System (ADS)

    Shin, Dong-Bin; Kim, Ju-Hye; Park, Hyo-Jin

    2011-08-01

    Global monthly precipitation is a critical element in understanding variability of the Earth's climate including changes in the hydrological cycle associated with global warming. The NCEP reanalysis (R1), GPCP, CMAP, and TMPA precipitation data sets are often used in climate studies. This study compares the data sets (R1, GPCP, CMAP, and TMPA) with the TRMM precipitation data sets derived from the TRMM precipitation radar (TPR), microwave imager (TMI), and combined algorithm (TCA) for 11 years (1998-2008) over the satellite's domain (40°S-40°N). The domain precipitation estimates from seven data sets range from 2.44 to 3.38 mm d-1 over the ocean and from 1.98 to 2.83 mm d-1 over land. The regional differences between the TPR and the other data sets are analyzed by a paired t test. Particularly, statistically significant differences between TPR and GPCP and between TPR and CMAP are found in most oceanic regions and in some land areas. In general, there exists substantial disagreement in precipitation intensities from the precipitation data sets. Therefore, significant consideration is given to the uncertainties in the data sets prior to applying the results to climate studies such as estimations of the global hydrological budget analyses. Meanwhile, the anomalies from all the data sets agree relatively well in their variability patterns. It is also found that the dominant mode of interannual variability which is associated with the ENSO pattern is clearly demonstrated by all precipitation data sets. These results suggest that all considered precipitation data sets may produce similar results when they are used for climate variability analyses on annual to interannual time scales.

  19. Influence of acid precipitation on stream invertebrates

    SciTech Connect

    Burton, T.M.; Allan, J.W.

    1983-09-01

    Five species of invertebrates, Asellus intermedius an isopod, Lepidostoma liba and Pycnopsyche sp., two species of caddisflies, Physa heterostropha, a snail, and a Nemoura sp., a stonefly, were tested for 30 days in 5 separate experiments for susceptibility to acidification to pH 4.0 and pH 5.0 alone or in combination with 250 to 500 micrograms Al/L. The effects of organic matter on the susceptibility of these invertebrates to acidification and aluminum toxicity were also tested. Acidification alone of natural stream water to pH 4.0 resulted in significant mortality for all 5 species. The addition of 500 micrograms Al/L significantly increased this mortality. Experiments with distilled water with inorganic chemistry adjusted to simulate natural stream water demonstrated that the absence of organic matter strongly resulted in much greater aluminum toxicity at low pH's and in somewhat greater susceptibility to acidification alone. The addition of citrate as an organic ligand decreased this effect. Thus, acidification effects for these 5 species for 30-day exposure periods only occurred at pH levels less than pH 5 and at aluminum levels greater than 250 micrograms Al/L. The threshold for effects, thus, was between pH 5 and pH 4 and between 250 and 500 micrograms Al/L. 19 references, 4 figures, 4 tables.

  20. Inhibition of histone deacetylases by trans-cinnamic acid and its antitumor effect against colon cancer xenografts in athymic mice

    PubMed Central

    ZHU, BINGYAN; SHANG, BOYANG; LI, YI; ZHEN, YONGSU

    2016-01-01

    Previous studies have shown that trans-cinnamic acid (tCA) has a broad spectrum of biological activities, and exhibits antioxidant, anti-inflammatory and anticancer properties. In addition, tCA and a variety of its analogs have been detected as gut microbe-derived metabolites exerting various biological effects in the colon. The aim of this study was to assess the antitumor activity of tCA in vitro and in vivo, in particular its therapeutic efficacy against colon cancer xenografts in athymic mice. Furthermore, it aimed to examine the effects of tCA on histone deacetylases (HDACs) and to identify the underlying molecular mechanisms. Using an MTT assay, tCA was observed to inhibit the proliferation of several cancer cell lines, and the half maximal inhibitory concentration (IC50) in HT29 colon carcinoma cells was ~1 mM. Western blot analysis demonstrated that tCA upregulated the expression of acetyl-H3 and acetyl-H4 proteins, which was consistent with the effects of the HDAC inhibitor, trichostatin A (TSA). Furthermore, expression of Bcl-2 (a marker of cell proliferation) was reduced, and apoptosis was induced. Apoptosis was shown by the activation of cleavage of poly ADP ribose polymerase and the increased expression of Bax. Apoptosis was also confirmed using APC Annexin V and SYTOX Green Nucleic Acid Stain. In addition, the tCA-induced inhibition of the expression of HDAC markers and activation of apoptosis in tumor tissues were further confirmed by immunohistochemistry. Intragastric administration of tCA at doses of 1.0 and 1.5 mmol/kg body weight suppressed the growth of HT29 human colon carcinoma xenografts in athymic mice at well-tolerated doses. No toxic changes were found in the heart, lung, liver, kidney, colon or bone marrow following histopathological examination. This study indicated that tCA is effective against colon cancer xenograft in nude mice. The antitumor mechanism of tCA was mediated, at least in part, by inhibition of HDACs in cancer cells. As

  1. Microbially Induced Precipitation of Strontianite Nanoparticles.

    PubMed

    Kang, Serku; Yumi Kim; Lee, Young Jae; Roh, Yul

    2015-07-01

    The objectives of this study were to investigate the microbially mediated precipitation of strontium by microorganisms, and to examine the mineralogical characteristics of the precipitates. Wu Do-1 (Proteus mirabilis) enriched from rhodoliths was used to precipitate strontium at room temperature under aerobic environment. The growth of Wu Do-1 gradually increased over 16 days (OD600 = 2.6) and then decreased until 22 days (OD600 = 2.0) during microbial incubation for strontium precipitation. Also, the pH decreased from 6.5 to 5.3 over 4 days of incubation due to microbial oxidation of organic acids, and then the pH increased up to 8.6 at 25 days of incubation due to NH3+ generation. The Sr2+ concentration in the biotic group sharply decreased from 2,953 mg/L to 5.7 mg/L over 29 days of incubation. XRD, SEM-/TEM-EDS analyses revealed that the precipitates formed by Wu Do-1 (Proteus mirabilis) were identified as 20-70 nm sized strontianite (SrCO3). Therefore, these results suggested that formation of sparingly soluble Sr precipitates mediated by Wu Do-1 (Proteus mirabilis) sequesters strontium and carbon dioxide into a more stable and less toxic form such as strontianite (SrCO3). These results also suggest that bioremediation of metal-contaminated water and biominealization of carbonate minerals may be feasible in the marine environment.

  2. as the Strengthening Precipitates

    NASA Astrophysics Data System (ADS)

    Lu, Qi; Xu, Wei; van der Zwaag, Sybrand

    2014-12-01

    Generally, Laves phase and M23C6 are regarded as undesirable phases in creep-resistant steels due to their very high-coarsening rates and the resulting depletion of beneficial alloying elements from the matrix. In this study, a computational alloy design approach is presented to develop martensitic steels strengthened by Laves phase and/or M23C6, for which the coarsening rates are tailored such that they are at least one order of magnitude lower than those in existing alloys. Their volume fractions are optimized by tuning the chemical composition in parallel. The composition domain covering 10 alloying elements at realistic levels is searched by a genetic algorithm to explore the full potential of simultaneous maximization of the volume fraction and minimization of the precipitates coarsening rate. The calculations show that Co and W can drastically reduce the coarsening rate of Laves and M23C6 and yield high-volume fractions of precipitates. Mo on the other hand was shown to have a minimal effect on coarsening. The strengthening effects of Laves phase and M23C6 in the newly designed alloys are compared to existing counterparts, showing substantially higher precipitation-strengthening contributions especially after a long service time. New alloys were designed in which both Laves phase and M23C6 precipitates act as strengthening precipitates. Successfully combining MX and M23C6 was found to be impossible.

  3. Precipitating factors of asthma.

    PubMed

    Lee, T H

    1992-01-01

    Asthma is characterised by bronchial hyperresponsiveness. This feature of the asthmatic diathesis predisposes patients to wheezing in response to a number of different factors. These precipitating factors include specific allergen acting via sensitised mediator cells through an IgE-dependent mechanism. There are irritants which may work through a non-specific manner, or stimuli such as exercise and hyperventilation, which probably also act through mediator release via a non-IgE-dependent manner. The mechanism whereby physical stimuli such as exercise induce bronchoconstriction is of interest, because it increases the context in which the mast cell may participate in acute asthmatic bronchoconstriction. Respiratory infections also commonly provoke asthma, especially in infants and may, indeed, precipitate the asthmatic state itself. Finally, drugs can often trigger asthma attacks and the mechanisms of asthma precipitated by non-steroidal anti-inflammatory drugs such as aspirin have been the subject of recent research.

  4. FORMATION OF URANIUM PRECIPITATES

    DOEpatents

    Googin, J.M. Jr.

    1959-03-17

    A method is described for precipitation of uranium peroxide from uranium- containing solutions so as to obtain larger aggregates which facilitates washings decantations filtrations centrifugations and the like. The desired larger aggregate form is obtained by maintaining the pH of the solution in the approximate range of 1 to 3 and the temperature at about 25 deg C or below while carrytng out the precipitation. Then prior to removal of the precipitate a surface active sulfonated bicarboxyacids such as di-octyl sodium sulfo-succinates is incorporated in an anount of the order of 0.01 to 0.05 percent by weights and the slurry is allowed to ripen for about one-half hour at a temperatare below 10 deg C.

  5. Precipitation-Regulated Feedback

    NASA Astrophysics Data System (ADS)

    Voit, Mark

    2016-07-01

    Star formation in the central galaxies of galaxy clusters appears to be fueled by precipitation of cold clouds out of hot circumgalactic gas via thermal instability. I will present both observational and theoretical support for the precipitation mode in large galaxies and discuss how it can be implemented in cosmological simulations of galaxy evolution. Galaxy cluster cores are unique laboratories for studying the astrophysics of thermal instability and may be teaching us valuable lessons about how feedback works in galaxies spanning the entire mass spectrum.

  6. Electrostatic particle precipitator

    SciTech Connect

    Uchiya, T.; Hikizi, S.; Yabuta, H.

    1984-04-03

    An electrostatic particle precipitator for removing dust particles from a flue gas. The precipitator includes a plurality of collecting electrodes in the shape of plates mounted on endless chains and moving between a first region through which flue gas to be treated flows and a second region where the flow of gas is extremely scarce. A dust removal mechanism is positioned in the second region to remove dust which accumulates on the electrode plates. The moving speed of the collecting electrodes is controlled within a certain range to maintain a prescribed thickness of dust on the electrodes whereby the ocurrence of reverse ionization phenomenon is prevented.

  7. Trichloroacetic acid in the vegetation of polluted and remote areas of both hemispheres—Part I. Its formation, uptake and geographical distribution

    NASA Astrophysics Data System (ADS)

    Weissflog, Ludwig; Pfennigsdorff, Andrea; Martinez-Pastur, Guillermo; Puliafito, Enrique; Figueroa, Dante; Elansky, Nikolai; Nikonov, Vyasheslav; Putz, Erich; Krüger, Gert; Kellner, Klaus

    Trichloroacetic acid (TCA; CCl 3COOH) is a phytotoxic chemical. Although TCA salts and derivatives were once deployed as herbicides against perennial grasses and weeds, their use has since been banned because of their indiscriminate herbicidal effects on woody plant species. However, TCA can also be formed in the atmosphere. For instance, high-volatile C 2-chlorohydrocarbons tetrachloroethene (TECE, C 2Cl 4) and 1,1,1-trichloroethane (TCE, CCl 3CH 3) can react to TCA and other substances under oxidative conditions here. Owing to further industrialisation of Southeast Asia, South Africa and South America, a rise can be expected in the use of TECE as solvents in the metal and textile industries of these regions in the southern hemisphere (SH). The increasing emissions of this substance—together with the rise in the atmospheric oxidation potential caused by urban activities, slash and burn agriculture and forest fires in the SH—will result in the increased input/formation of TCA in the vegetation located on the lee side of these emission sources. By means of biomonitoring studies, inputs/formation of TCA related to the climatic conditions were detected at various locations in South America, Africa, and Europe.

  8. Investigation of Neptunium Precipitator Cleanout Options

    SciTech Connect

    Hill, B.C.

    2003-09-08

    Oxalate precipitation followed by filtration is used to prepare plutonium oxalate. Historically, plutonium oxalate has tended to accumulate in the precipitation tanks. These solids are periodically removed by flushing with concentrated (64 percent) nitric acid. The same precipitation tanks will now be used in the processing of neptunium. Literature values indicate that neptunium oxalate may not be as soluble as plutonium oxalate in nitric acid. Although a wide variety of options is available to improve neptunium oxalate solubility for precipitator flushing, most of these options are not practical for use. Many of these options require the use of incompatible or difficult to handle chemicals. Other options would require expensive equipment modifications or are likely to lead to product contamination. Based on review of literature and experimental results, the two best options for flushing the precipitator are (1) 64 percent nitric acid and (2) addition of sodium permanganate follow ed by sodium nitrite. Nitric acid is the easiest option to implement. It is already used in the facility and will not lead to product contamination. Experimental results indicate that neptunium oxalate can be dissolved in concentrated nitric acid (64 percent) at 60 degree C to a concentration of 2.6 to 5.6 grams of Np/liter after at least three hours of heating. A lower concentration (1.1 grams of Np/liter) was measured at 60 degree C after less than two hours of heating. These concentrations are acceptable for flushing if precipitator holdup is low (approximately 100-250 grams), but a second method is required for effective flushing if precipitator holdup is high (approximately 2 kilograms). The most effective method for obtaining higher neptunium concentrations is the use of sodium permanganate followed by the addition of sodium nitrite. There is concern that residual manganese from these flushes could impact product purity. Gas generation during permanganate addition is also a concern

  9. Branched Tricarboxylic Acid Metabolism in Plasmodium falciparum

    PubMed Central

    Olszewski, Kellen L.; Mather, Michael W.; Morrisey, Joanne M.; Garcia, Benjamin A.; Vaidya, Akhil B.; Rabinowitz, Joshua D.; Llinás, Manuel

    2010-01-01

    A central hub of carbon metabolism is the tricarboxylic acid (TCA) cycle1, which serves to connect the processes of glycolysis, gluconeogenesis, respiration, amino acid synthesis and other biosynthetic pathways. The protozoan intracellular malaria parasites (Plasmodium spp.), however, have long been suspected of possessing a significantly streamlined carbon metabolic network in which TCA metabolism plays a minor role2. Blood-stage Plasmodium parasites rely almost entirely on glucose fermentation for energy and consume minimal amounts of oxygen3, yet the parasite genome encodes all of the enzymes necessary for a complete TCA cycle4. By tracing 13C-labeled compounds using mass spectrometry5 we show that TCA metabolism in the human malaria parasite P. falciparum is largely disconnected from glycolysis and is organized along a fundamentally different architecture than the canonical textbook pathway. We find that this pathway is not cyclic but rather a branched structure in which the major carbon sources are the amino acids glutamate and glutamine. As a consequence of this branched architecture, several reactions must run in the reverse of the standard direction thereby generating two-carbon units in the form of acetyl-coenzyme A (acetyl-CoA). We further show that glutamine-derived acetyl-CoA is used for histone acetylation while glucose-derived acetyl-CoA is used to acetylate aminosugars. Thus the parasite has evolved two independent acetyl-CoA-production mechanisms with different biological functions. These results significantly clarify our understanding of the Plasmodium metabolic network and highlight the ability of altered variants of central carbon metabolism to arise in response to unique environments. PMID:20686576

  10. The tricarboxylic acid cycle in Shewanella oneidensis is independent of Fur and RyhB control

    SciTech Connect

    Yang, Yunfeng; McCue, Lee Ann; Parsons, Andrea; Feng, Sheng; Zhou, Jizhong

    2010-01-01

    Background: It is well established in E. coli and Vibrio cholerae that strains harboring mutations in the ferric uptake regulator gene (fur) are unable to utilize tricarboxylic acid (TCA) compounds, due to the down-regulation of key TCA cycle enzymes, such as AcnA and SdhABCD. This down-regulation is mediated by a Fur-regulated small regulatory RNA named RyhB. It is unclear in the g-proteobacterium S. oneidensis whether TCA is also regulated by Fur and RyhB. Results: In the present study, we showed that a fur deletion mutant of S. oneidensis could utilize TCA compounds. Consistently, expression of the TCA cycle genes acnA and sdhA was not down-regulated in the mutant. To explore this observation further, we identified a ryhB gene in Shewanella species and experimentally demonstrated the gene expression. Further experiments suggested that RyhB was up-regulated in fur mutant, but that AcnA and SdhA were not controlled by RyhB. Conclusions: These cumulative results delineate an important difference of the Fur-RyhB regulatory cycle between S. oneidensis and other g-proteobacteria. This work represents a step forward for understanding the unique regulation in S. oneidensis.

  11. The Global Precipitation Mission

    NASA Technical Reports Server (NTRS)

    Braun, Scott; Kummerow, Christian

    2000-01-01

    The Global Precipitation Mission (GPM), expected to begin around 2006, is a follow-up to the Tropical Rainfall Measuring Mission (TRMM). Unlike TRMM, which primarily samples the tropics, GPM will sample both the tropics and mid-latitudes. The primary, or core, satellite will be a single, enhanced TRMM satellite that can quantify the 3-D spatial distributions of precipitation and its associated latent heat release. The core satellite will be complemented by a constellation of very small and inexpensive drones with passive microwave instruments that will sample the rainfall with sufficient frequency to be not only of climate interest, but also have local, short-term impacts by providing global rainfall coverage at approx. 3 h intervals. The data is expected to have substantial impact upon quantitative precipitation estimation/forecasting and data assimilation into global and mesoscale numerical models. Based upon previous studies of rainfall data assimilation, GPM is expected to lead to significant improvements in forecasts of extratropical and tropical cyclones. For example, GPM rainfall data can provide improved initialization of frontal systems over the Pacific and Atlantic Oceans. The purpose of this talk is to provide information about GPM to the USWRP (U.S. Weather Research Program) community and to discuss impacts on quantitative precipitation estimation/forecasting and data assimilation.

  12. Global precipitation measurement (GPM)

    NASA Astrophysics Data System (ADS)

    Neeck, Steven P.; Flaming, Gilbert M.; Adams, W. James; Smith, Eric A.

    2001-12-01

    The National Aeronautics and Space Administration (NASA) is studying options for future space-based missions for the EOS Follow-on Era (post 2003), building upon the measurements made by Pre-EOS and EOS First Series Missions. One mission under consideration is the Global Precipitation Measurement (GPM), a cooperative venture of NASA, Japan, and other international partners. GPM will capitalize on the experience of the highly successful Tropical Rainfall Measurement Mission (TRMM). Its goal is to extend the measurement of rainfall to high latitudes with high temporal frequency, providing a global data set every three hours. A reference concept has been developed consisting of an improved TRMM-like primary satellite with precipitation radar and microwave radiometer to make detailed and accurate estimates of the precipitation structure and a constellation of small satellites flying compact microwave radiometers to provide the required temporal sampling of highly variable precipitation systems. Considering that DMSP spacecraft equipped with SSMIS microwave radiometers, successor NPOESS spacecraft equipped with CMIS microwave radiometers, and other relevant international systems are expected to be in operation during the timeframe of the reference concept, the total number of small satellites required to complete the constellation will be reduced. A nominal plan is to begin implementation in FY'03 with launches in 2007. NASA is presently engaged in advanced mission studies and advanced instrument technology development related to the mission.

  13. Total Precipitable Water

    SciTech Connect

    2012-01-01

    The simulation was performed on 64K cores of Intrepid, running at 0.25 simulated-years-per-day and taking 25 million core-hours. This is the first simulation using both the CAM5 physics and the highly scalable spectral element dynamical core. The animation of Total Precipitable Water clearly shows hurricanes developing in the Atlantic and Pacific.

  14. Cross-talk between branched-chain amino acids and hepatic mitochondria is compromised in nonalcoholic fatty liver disease.

    PubMed

    Sunny, Nishanth E; Kalavalapalli, Srilaxmi; Bril, Fernando; Garrett, Timothy J; Nautiyal, Manisha; Mathew, Justin T; Williams, Caroline M; Cusi, Kenneth

    2015-08-15

    Elevated plasma branched-chain amino acids (BCAA) in the setting of insulin resistance have been relevant in predicting type 2 diabetes mellitus (T2DM) onset, but their role in the etiology of hepatic insulin resistance remains uncertain. We determined the link between BCAA and dysfunctional hepatic tricarboxylic acid (TCA) cycle, which is a central feature of hepatic insulin resistance and nonalcoholic fatty liver disease (NAFLD). Plasma metabolites under basal fasting and euglycemic hyperinsulinemic clamps (insulin stimulation) were measured in 94 human subjects with varying degrees of insulin sensitivity to identify their relationships with insulin resistance. Furthermore, the impact of elevated BCAA on hepatic TCA cycle was determined in a diet-induced mouse model of NAFLD, utilizing targeted metabolomics and nuclear magnetic resonance (NMR)-based metabolic flux analysis. Insulin stimulation revealed robust relationships between human plasma BCAA and indices of insulin resistance, indicating chronic metabolic overload from BCAA. Human plasma BCAA and long-chain acylcarnitines also showed a positive correlation, suggesting modulation of mitochondrial metabolism by BCAA. Concurrently, mice with NAFLD failed to optimally induce hepatic mTORC1, plasma ketones, and hepatic long-chain acylcarnitines, following acute elevation of plasma BCAA. Furthermore, elevated BCAA failed to induce multiple fluxes through hepatic TCA cycle in mice with NAFLD. Our data suggest that BCAA are essential to mediate efficient channeling of carbon substrates for oxidation through mitochondrial TCA cycle. Impairment of BCAA-mediated upregulation of the TCA cycle could be a significant contributor to mitochondrial dysfunction in NAFLD. PMID:26058864

  15. Effect of trichloroacetic acid on the isolation of tropomyosin from sea urchin lantern muscle.

    PubMed

    Ishimoda-Takagi, T; Ozaki, S

    1983-03-01

    Sea urchin lantern muscle tropomyosin showed two components in sodium dodecyl sulfate (SDS) gel electrophoresis in the presence of 5 M urea, although the molecular weights of these components were apparently identical. One of these components seemed to have been digested with an enzyme such as carboxypeptidase, and the tropomyosin had lost the abilities to polymerize and to bind to actin. A crude extract prepared from the lantern muscle treated with trichloroacetic acid (TCA) contained predominantly tropomyosin. Tropomyosin purified from TCA-treated lantern muscle seemed to be intact and retained the ability to bind to actin.

  16. Uncertainty of Prebiotic Scenarios: The Case of the Non-Enzymatic Reverse Tricarboxylic Acid Cycle

    NASA Astrophysics Data System (ADS)

    Zubarev, Dmitry; Rappoport, Dmitrij; Aspuru-Guzik, Alan

    2015-03-01

    We consider the much discussed hypothesis of the primordial nature of the non-enzymatic reverse tricarboxylic acid (rTCA) cycle and describe a modeling approach that quantifies the uncertainty of this hypothesis due to the combinatorial aspect of the constituent chemical transformations. Our results suggest that a) rTCA cycle belongs to a degenerate optimum of auto-catalytic cycles, and b) the set of targets for the investigations of the origin of the common metabolic core should be significantly extended. This work was supported by a grant from the Simons Foundation (SCOL 291937, Dmitry Zubarev).

  17. Precipitation Indices Low Countries

    NASA Astrophysics Data System (ADS)

    van Engelen, A. F. V.; Ynsen, F.; Buisman, J.; van der Schrier, G.

    2009-09-01

    Since 1995, KNMI published a series of books(1), presenting an annual reconstruction of weather and climate in the Low Countries, covering the period AD 763-present, or roughly, the last millennium. The reconstructions are based on the interpretation of documentary sources predominantly and comparison with other proxies and instrumental observations. The series also comprises a number of classifications. Amongst them annual classifications for winter and summer temperature and for winter and summer dryness-wetness. The classification of temperature have been reworked into peer reviewed (2) series (AD 1000-present) of seasonal temperatures and temperature indices, the so called LCT (Low Countries Temperature) series, now incorporated in the Millennium databases. Recently we started a study to convert the dryness-wetness classifications into a series of precipitation; the so called LCP (Low Countries Precipitation) series. A brief outline is given here of the applied methodology and preliminary results. The WMO definition for meteorological drought has been followed being that a period is called wet respectively dry when the amount of precipitation is considerable more respectively less than usual (normal). To gain a more quantitative insight for four locations, geographically spread over the Low Countries area (De Bilt, Vlissingen, Maastricht and Uccle), we analysed the statistics of daily precipitation series, covering the period 1900-present. This brought us to the following definition, valid for the Low Countries: A period is considered as (very) dry respectively (very) wet if over a continuous period of at least 60 days (~two months) cq 90 days (~three months) on at least two out of the four locations 50% less resp. 50% more than the normal amount for the location (based on the 1961-1990 normal period) has been measured. This results into the following classification into five drought classes hat could be applied to non instrumental observations: Very wet period

  18. Acid rain

    SciTech Connect

    Sweet, W.

    1980-06-20

    Acid precipitation includes not only rain but also acidified snow, hail and frost, as well as sulfur and nitrogen dust. The principal source of acid precipitation is pollution emitted by power plants and smelters. Sulfur and nitrogen compounds contained in the emissions combine with moisture to form droplets with a high acid content - sometimes as acidic as vinegar. When sufficiently concentrated, these acids can kill fish and damage material structures. Under certain circumstances they may reduce crop and forest yields and cause or aggravate respiratory diseases in humans. During the summer, especially, pollutants tend to collect over the Great Lakes in high pressure systems. Since winds typically are westerly and rotate clockwise around high pressure systems, the pollutants gradually are dispersed throughout the eastern part of the continent.

  19. Lack of formic acid production in rat hepatocytes and human renal proximal tubule cells exposed to chloral hydrate or trichloroacetic acid.

    PubMed

    Lock, Edward A; Reed, Celia J; McMillan, Joellyn M; Oatis, John E; Schnellmann, Rick G

    2007-02-12

    The industrial solvent trichloroethylene (TCE) and its major metabolites have been shown to cause formic aciduria in male rats. We have examined whether chloral hydrate (CH) and trichloroacetic acid (TCA), known metabolites of TCE, produce an increase in formic acid in vitro in cultures of rat hepatocytes or human renal proximal tubule cells (HRPTC). The metabolism and cytotoxicity of CH was also examined to establish that the cells were metabolically active and not compromised by toxicity. Rat hepatocytes and HRPTC were cultured in serum-free medium and then treated with 0.3-3mM CH for 3 days or 0.03-3mM CH for 10 days, respectively and formic acid production, metabolism to trichloroethanol (TCE-OH) and TCA and cytotoxicity determined. No increase in formic acid production in rat hepatocytes or HRPTC exposed to CH was observed over and above that due to chemical degradation, neither was formic acid production observed in rat hepatocytes exposed to TCA. HRPTC metabolized CH to TCE-OH and TCA with a 12-fold greater capacity to form TCE-OH versus TCA. Rat hepatocytes exhibited a 1.6-fold and three-fold greater capacity than HRPTC to form TCE-OH and TCA, respectively. CH and TCA were not cytotoxic to rat hepatocytes at concentrations up to 3mM/day for 3 days. With HRPTC, one sample showed no cytotoxicity to CH at concentrations up to 3mM/day for 10 days, while in another cytotoxicity was seen at 1mM/day for 3 days. In summary, increased formic acid production was not observed in rat hepatocytes or HRPTC exposed to TCE metabolites, suggesting that the in vivo response cannot be modelled in vitro. CH was toxic to HRPTC at millimolar concentrations/day over 10 days, while glutathione derived metabolites of TCE were toxic at micromolar concentrations/day over 10 days [Lock, E.A., Reed, C.J., 2006. Trichloroethylene: mechanisms of renal toxicity and renal cancer and relevance to risk assessment. Toxicol. Sci. 19, 313-331] supporting the view that glutathione derived

  20. Anthropogenic Osmium in Precipitation

    NASA Astrophysics Data System (ADS)

    Chen, C.; Sedwick, P. N.; Sharma, M.

    2007-12-01

    Here we report the Os isotopic composition for precipitation from Hanover (NH), Soda Springs (CA) and the Ross Sea (Antarctica) as determined by negative thermal ionization mass spectrometry. All samples yielded non- radiogenic Os isotopic compositions. Snow and rain samples from Hanover, NH had Os concentrations of 0.8 - 12.2 fg/g (1 fg/g = 1E-15 g/g) and 187Os/188Os from 0.16 - 0.24. Snowpack from the high Sierra Nevada (Central Sierra Snow Laboratory, Soda Springs, CA) yielded Os concentration and isotopic composition of 3.6 fg/g and 0.21, respectively; Antarctic snow deposited above first year pack ice had [Os] = 0.8 fg/g and 187Os/188Os = 0.42. The isotopic ratios indicate that potential natural sources of Os to the atmosphere, such as continental mineral aerosols (187Os/188Os = 1.26) and seawater (187Os/188Os = 1.05) do not contribute bulk of Os to the precipitation. Instead, the isotopic ratios are identical to the platinum ores from the Merensky Reef in the Bushveld Igneous Complex, South Africa and Noril'sk Ni-Cu sulfide deposit associated with the Siberian Flood Basalts, Russia. These two deposits produce greater than 95 percent of the total Pt, Pd and Rh consumed annually primarily by the automotive industry. We infer that anthropogenic Os contribution dominates the isotopic composition of precipitation. The similar and non-radiogenic Os isotopic compositions observed in precipitation from disparate locations suggest that contamination of the troposphere with anthropogenic Os may be global in scale. We think that processing of ore to extract Pt, Pd, and Rh from PGE ores (PGE: group of six closely related elements Os, Ir, Pt, Pd, Rh, and Ru), which involves smelting and converting at high temperature and in the presence of oxygen, releases the volatile, toxic compound OsO4 into the troposphere, where it is mixed and then scavenged by precipitation, thus explaining both the non-radiogenic isotopic composition and the high and variable Os concentrations of

  1. Regulating Pyruvate Carboxylase in the Living Culture of Aspergillus Terreus Nrrl 1960 by L-Aspartate for Enhanced Itaconic Acid Production.

    PubMed

    Songserm, Pajareeya; Thitiprasert, Sitanan; Tolieng, Vasana; Piluk, Jiraporn; Tanasupawat, Somboon; Assabumrungrat, Sutthichai; Yang, Shang-Tian; Karnchanatat, Aphichart; Thongchul, Nuttha

    2015-10-01

    Aspergillus terreus was reported as the promising fungal strain for itaconic acid; however, the commercial production suffers from the low yield. Low production yield was claimed as the result of completing the tricarboxylic acid (TCA) cycle towards biomass synthesis while under limiting phosphate and nitrogen; TCA cycle was somewhat shunted and consequently, the metabolite fluxes move towards itaconic acid production route. By regulating enzymes in TCA cycle, it is believed that itaconic acid production can be improved. One of the key responsible enzymes involved in itaconic acid production was triggered in this study. Pyruvate carboxylase was allosterically inhibited by L-aspartate. The presence of 10 mM L-aspartate in the production medium directly repressed PC expression in the living A. terreus while the limited malate flux regulated the malate/citrate antiporters resulting in the increasing cis-aconitate decarboxylase activity to simultaneously convert cis-aconitate, citrate isomer, into itaconic acid. The transport of cis-aconitate via the antiporters induced citrate synthase and 6-phosphofructo-1-kinase activities in response to balance the fluxes of TCA intermediates. Successively, itaconic acid production yield and final concentration could be improved by 8.33 and 60.32 %, respectively, compared to those obtained from the control fermentation with the shortened lag time to produce itaconic acid during the production phase.

  2. Biosynthesis of pyruvic acid from glucose by Blastobotrys adeninivorans.

    PubMed

    Kamzolova, Svetlana V; Morgunov, Igor G

    2016-09-01

    The ability of taxonomically different yeasts to synthesize pyruvic acid (PA) from glucose was studied. The study showed that many yeasts are able to produce PA from glucose under the condition of growth limitation by thiamine. This ability was found in the yeast Blastobotrys adeninivorans for the first time. The production (oversynthesis) of PA in this yeast can be explained by disturbance in the function of thiamine-dependent pyruvate dehydrogenase. Namely, the partial inhibition of this enzyme brings about the excretion of PA from the yeast cells. Due to incomplete inhibition of pyruvate dehydrogenase, the formation of acetyl-CoA continues, although at a lower level, maintaining the synthesis of α-ketoglutaric acid (KGA) in the tricarboxylic acid (TCA) cycle. KGA is no longer oxidized in the TCA cycle, because thiamine limitation inhibits α-ketoglutarate dehydrogenase. As a result, KGA is excreted from the yeast cells as a byproduct of PA oversynthesis. Furthermore, the increased level of KGA in the yeast cells inhibits NAD-dependent isocitrate dehydrogenase in the TCA cycle and enhances the production and excretion of citric acid, another byproduct of PA oversynthesis. During cultivation in a fermentor, the strain Blastobotrys adeninivorans VKM Y-2677 produced 43.2 g l(-1) PA from glucose with a product yield (YPA) of 0.77 g PA/g glucose. The proportion of PA to byproducts was 18:1 for KGA and 8:1 for citric acid.

  3. Precipitation hardening austenitic superalloys

    DOEpatents

    Korenko, Michael K.

    1985-01-01

    Precipitation hardening, austenitic type superalloys are described. These alloys contain 0.5 to 1.5 weight percent silicon in combination with about 0.05 to 0.5 weight percent of a post irradiation ductility enhancing agent selected from the group of hafnium, yttrium, lanthanum and scandium, alone or in combination with each other. In addition, when hafnium or yttrium are selected, reductions in irradiation induced swelling have been noted.

  4. Effect of calcium oxide on the efficiency of ferrous ion oxidation and total iron precipitation during ferrous ion oxidation in simulated acid mine drainage treatment with inoculation of Acidithiobacillus ferrooxidans.

    PubMed

    Liu, Fenwu; Zhou, Jun; Jin, Tongjun; Zhang, Shasha; Liu, Lanlan

    2016-01-01

    Calcium oxide was added into ferrous ion oxidation system in the presence of Acidithiobacillus ferrooxidans at concentrations of 0-4.00 g/L. The pH, ferrous ion oxidation efficiency, total iron precipitation efficiency, and phase of the solid minerals harvested from different treatments were investigated during the ferrous ion oxidation process. In control check (CK) system, pH of the solution decreased from 2.81 to 2.25 when ferrous ions achieved complete oxidation after 72 h of Acidithiobacillus ferrooxidans incubation without the addition of calcium oxide, and total iron precipitation efficiency reached 20.2%. Efficiency of ferrous ion oxidation and total iron precipitation was significantly improved when the amount of calcium oxide added was ≤1.33 g/L, and the minerals harvested from systems were mainly a mixture of jarosite and schwertmannite. For example, the ferrous ion oxidation efficiency reached 100% at 60 h and total iron precipitation efficiency was increased to 32.1% at 72 h when 1.33 g/L of calcium oxide was added. However, ferrous ion oxidation and total iron precipitation for jarosite and schwertmannite formation were inhibited if the amount of calcium oxide added was above 2.67 g/L, and large amounts of calcium sulfate dihydrate were generated in systems.

  5. Duskside relativistic electron precipitation

    NASA Astrophysics Data System (ADS)

    Lorentzen, Kirsten Ruth

    1999-10-01

    On August 20, 1996, a balloon-borne X-ray pinhole camera and a high resolution germanium X-ray spectrometer observed an intense X-ray event near Kiruna, Sweden, at 1835 MLT, on an L-shell of 5.8. This X-ray event consisted of seven bursts spaced 100-200 seconds apart, with smaller 10-20 second variations observed within individual bursts. The energy spectra of these bursts show the presence of X-rays with energies greater than 1 MeV, which are best accounted for by atmospheric bremsstrahlung from mono-energetic 1.7 MeV precipitating electrons. The X-ray imager observed no significant motion or small-scale spatial structure in the event, implying that the bursts were temporal in nature. Ultra- violet images from the Polar satellite and energetic particle data from the Los Alamos geosynchronous satellites show a small magnetospheric substorm onset about 24 minutes before the start of the relativistic precipitation event. Since the balloon was south of the auroral oval and there was no associated increase in relativistic electron flux at geosynchronous altitude, the event must be the result of some mechanism selectively precipitating ambient relativistic electrons from the radiation belts. The balloon X-ray observations are analyzed in a magnetospheric context, in order to determine which of several mechanisms for selective precipitation of relativistic electrons can account for the event. Resonance with electromagnetic ion cyclotron mode waves on the equator is the most likely candidate. The drift of substorm-injected warm protons is calculated using input from the geosynchronous satellites. Wave growth in the model is driven by temperature anisotropies in the warm proton population. A numerical solution of the wave dispersion relation shows that electromagnetic ion cyclotron waves can be excited in high-density duskside regions such as the plasmasphere or detached plasma regions. These waves can selectively precipitate relativistic electrons of energy 1.7 MeV in

  6. The CC chemokine thymus-derived chemotactic agent 4 (TCA-4, secondary lymphoid tissue chemokine, 6Ckine, exodus-2) triggers lymphocyte function-associated antigen 1-mediated arrest of rolling T lymphocytes in peripheral lymph node high endothelial venules.

    PubMed

    Stein, J V; Rot, A; Luo, Y; Narasimhaswamy, M; Nakano, H; Gunn, M D; Matsuzawa, A; Quackenbush, E J; Dorf, M E; von Andrian, U H

    2000-01-01

    T cell homing to peripheral lymph nodes (PLNs) is defined by a multistep sequence of interactions between lymphocytes and endothelial cells in high endothelial venules (HEVs). After initial tethering and rolling via L-selectin, firm adhesion of T cells requires rapid upregulation of lymphocyte function-associated antigen 1 (LFA-1) adhesiveness by a previously unknown pathway that activates a Galpha(i)-linked receptor. Here, we used intravital microscopy of murine PLNs to study the role of thymus-derived chemotactic agent (TCA)-4 (secondary lymphoid tissue chemokine, 6Ckine, Exodus-2) in homing of adoptively transferred T cells from T-GFP mice, a transgenic strain that expresses green fluorescent protein (GFP) selectively in naive T lymphocytes (T(GFP) cells). TCA-4 was constitutively presented on the luminal surface of HEVs, where it was required for LFA-1 activation on rolling T(GFP) cells. Desensitization of the TCA-4 receptor, CC chemokine receptor 7 (CCR7), blocked T(GFP) cell adherence in wild-type HEVs, whereas desensitization to stromal cell-derived factor (SDF)-1alpha (the ligand for CXC chemokine receptor 4 [CXCR4]) did not affect T(GFP) cell behavior. TCA-4 protein was not detected on the luminal surface of PLN HEVs in plt/plt mice, which have a congenital defect in T cell homing to PLNs. Accordingly, T(GFP) cells rolled but did not arrest in plt/plt HEVs. When TCA-4 was injected intracutaneously into plt/plt mice, the chemokine entered afferent lymph vessels and accumulated in draining PLNs. 2 h after intracutaneous injection, luminal presentation of TCA-4 was detectable in a subset of HEVs, and LFA-1-mediated T(GFP) cell adhesion was restored in these vessels. We conclude that TCA-4 is both required and sufficient for LFA-1 activation on rolling T cells in PLN HEVs. This study also highlights a hitherto undocumented role for chemokines contained in afferent lymph, which may modulate leukocyte recruitment in draining PLNs.

  7. Trans-Cinnamic Acid Increases Adiponectin and the Phosphorylation of AMP-Activated Protein Kinase through G-Protein-Coupled Receptor Signaling in 3T3-L1 Adipocytes

    PubMed Central

    Kopp, Christina; Singh, Shiva P.; Regenhard, Petra; Müller, Ute; Sauerwein, Helga; Mielenz, Manfred

    2014-01-01

    Adiponectin and intracellular 5′adenosine monophosphate-activated protein kinase (AMPK) are important modulators of glucose and fat metabolism. Cinnamon exerts beneficial effects by improving insulin sensitivity and blood lipids, e.g., through increasing adiponectin concentrations and AMPK activation. The underlying mechanism is unknown. The Gi/Go-protein-coupled receptor (GPR) 109A stimulates adiponectin secretion after binding its ligand niacin. Trans-cinnamic acid (tCA), a compound of cinnamon is another ligand. We hypothesize whether AMPK activation and adiponectin secretion by tCA is transmitted by GPR signaling. Differentiated 3T3-L1 cells were incubated with pertussis toxin (PTX), an inhibitor of Gi/Go-protein-coupling, and treated with different tCA concentrations. Treatment with tCA increased adiponectin and the pAMPK/AMPK ratio (p ≤ 0.001). PTX incubation abolished the increased pAMPK/AMPK ratio and adiponectin secretion. The latter remained increased compared to controls (p ≤ 0.002). tCA treatment stimulated adiponectin secretion and AMPK activation; the inhibitory effect of PTX suggests GPR is involved in tCA stimulated signaling. PMID:24557583

  8. Precipitation Indices Low Countries

    NASA Astrophysics Data System (ADS)

    van Engelen, A. F. V.; Ynsen, F.; Buisman, J.; van der Schrier, G.

    2009-09-01

    Since 1995, KNMI published a series of books(1), presenting an annual reconstruction of weather and climate in the Low Countries, covering the period AD 763-present, or roughly, the last millennium. The reconstructions are based on the interpretation of documentary sources predominantly and comparison with other proxies and instrumental observations. The series also comprises a number of classifications. Amongst them annual classifications for winter and summer temperature and for winter and summer dryness-wetness. The classification of temperature have been reworked into peer reviewed (2) series (AD 1000-present) of seasonal temperatures and temperature indices, the so called LCT (Low Countries Temperature) series, now incorporated in the Millennium databases. Recently we started a study to convert the dryness-wetness classifications into a series of precipitation; the so called LCP (Low Countries Precipitation) series. A brief outline is given here of the applied methodology and preliminary results. The WMO definition for meteorological drought has been followed being that a period is called wet respectively dry when the amount of precipitation is considerable more respectively less than usual (normal). To gain a more quantitative insight for four locations, geographically spread over the Low Countries area (De Bilt, Vlissingen, Maastricht and Uccle), we analysed the statistics of daily precipitation series, covering the period 1900-present. This brought us to the following definition, valid for the Low Countries: A period is considered as (very) dry respectively (very) wet if over a continuous period of at least 60 days (~two months) cq 90 days (~three months) on at least two out of the four locations 50% less resp. 50% more than the normal amount for the location (based on the 1961-1990 normal period) has been measured. This results into the following classification into five drought classes hat could be applied to non instrumental observations: Very wet period

  9. METHOD OF IMPROVING THE CARRIER PRECIPITATION OF PLUTONIUM

    DOEpatents

    Kamack, H.J.; Balthis, J.H.

    1958-12-01

    Plutonium values can be recovered from acidic solutlons by adding lead nitrate, hydrogen fluoride, lantha num nitrate, and sulfurlc acid to the solution to form a carrler preclpitate. The lead sulfate formed improves the separatlon characteristics of the lanthanum fluoride carrier precipitate,

  10. Chemical composition of precipitation and its sources in Hangzhou, China.

    PubMed

    Xu, Hong; Bi, Xiao-Hui; Feng, Yin-Chang; Lin, Feng-Mei; Jiao, Li; Hong, Sheng-Mao; Liu, Wen-Gao; Zhang, Xiao-Yong

    2011-12-01

    To understand the origin and chemical characteristics of precipitation in Hangzhou, rainwater samples were collected from June 2006 to May 2008. All samples were analyzed for pH, electrical conductivity, and major ions (NH⁴⁺, Ca²⁺, Mg²⁺, Na⁺, K⁺, SO₄²⁻, NO₃⁻, F⁻, and Cl⁻). Acidification of precipitation in Hangzhou was serious with volume-weighted mean pH value of 4.5, while frequency of acid rain was 95%. The calculated SO₄²⁻/NO₃⁻ ratio in Hangzhou precipitation was 2.87, which indicated that the precipitation of Hangzhou belonged to sulfate-based acid rain. The results of acid neutralization analysis showed that not all the acidity in the precipitation of Hangzhou was neutralized by alkaline constituents. The results of sea salt contribution analysis showed that nearly all SO₄²⁻, Ca²⁺, and Mg²⁺ and 33.7% of K⁺ were of non-sea origins, while all Na⁺ and Cl⁻ and 66.3% of K⁺ originated from sea sources. The principal component analysis which was used to analyze the sources of various ions indicated that chemical compositions of precipitation in Hangzhou mainly came from terrestrial sources, factory emissions, fuel wood burning, and marine sources.

  11. Analysis of precipitation chemistry at a central Pennsylvania site

    NASA Astrophysics Data System (ADS)

    Bowersox, Van C.; de Pena, Rosa G.

    1980-10-01

    As part of the multistate atmospheric power production pollution study precipitation chemistry network, precipitation has been sampled on a storm-by-storm basis at a rural central Pennsylvania site operated by Pennsylvania State University since October 1976. These precipitation data have been analyzed for sulfate, nitrate, ammonium, and hydronium ions for the years 1977 and 1978, and both years exhibit the same general behavior with respect to these chemical species: (1) sulfate concentration in precipitation varies with season, with high values in the summer and low values in the winter, (2) sulfate ion is the major determinant of precipitation acidity, though sulfate alone does not account for the total H3O+ concentration, (for snow and other frozen precipitation the relation between sulfate and H3O+ is less pronounced), (3) nitrate ion of concentrations similar to those of sulfate does not correlate well with hydronium ion in liquid precipitation but does correlate with H3O+ in snow and frozen precipitation, and (4) ammonium ion concentrations in precipitation can be explained by assuming an equilibrium state between the cloud water and gas phase ammonia.

  12. Inhibition of Pyruvate Dehydrogenase Kinase 2 Protects Against Hepatic Steatosis Through Modulation of Tricarboxylic Acid Cycle Anaplerosis and Ketogenesis.

    PubMed

    Go, Younghoon; Jeong, Ji Yun; Jeoung, Nam Ho; Jeon, Jae-Han; Park, Bo-Yoon; Kang, Hyeon-Ji; Ha, Chae-Myeong; Choi, Young-Keun; Lee, Sun Joo; Ham, Hye Jin; Kim, Byung-Gyu; Park, Keun-Gyu; Park, So Young; Lee, Chul-Ho; Choi, Cheol Soo; Park, Tae-Sik; Lee, W N Paul; Harris, Robert A; Lee, In-Kyu

    2016-10-01

    Hepatic steatosis is associated with increased insulin resistance and tricarboxylic acid (TCA) cycle flux, but decreased ketogenesis and pyruvate dehydrogenase complex (PDC) flux. This study examined whether hepatic PDC activation by inhibition of pyruvate dehydrogenase kinase 2 (PDK2) ameliorates these metabolic abnormalities. Wild-type mice fed a high-fat diet exhibited hepatic steatosis, insulin resistance, and increased levels of pyruvate, TCA cycle intermediates, and malonyl-CoA but reduced ketogenesis and PDC activity due to PDK2 induction. Hepatic PDC activation by PDK2 inhibition attenuated hepatic steatosis, improved hepatic insulin sensitivity, reduced hepatic glucose production, increased capacity for β-oxidation and ketogenesis, and decreased the capacity for lipogenesis. These results were attributed to altered enzymatic capacities and a reduction in TCA anaplerosis that limited the availability of oxaloacetate for the TCA cycle, which promoted ketogenesis. The current study reports that increasing hepatic PDC activity by inhibition of PDK2 ameliorates hepatic steatosis and insulin sensitivity by regulating TCA cycle anaplerosis and ketogenesis. The findings suggest PDK2 is a potential therapeutic target for nonalcoholic fatty liver disease.

  13. Characterisation of Suspension Precipitated Nanocrystalline Hydroxyapatite Powders

    NASA Astrophysics Data System (ADS)

    Mallik, P. K.; Swain, P. K.; Patnaik, S. C.

    2016-02-01

    Hydroxyapatite (HA) is a well-known biomaterial for coating on femoral implants, filling of dental cavity and scaffold for tissue replacement. Hydroxyapatite possess limited load bearing capacity due to their brittleness. In this paper, the synthesis of nanocrystalline hydroxyapatite powders was prepared by dissolving calcium oxide in phosphoric acid, followed by addition of ammonia liquor in a beaker. The prepared solution was stirred by using magnetic stirrer operated at temperature of 80°C for an hour. This leads to the formation of hydroxyapatite precipitate. The precipitate was dried in oven for overnight at 100°C. The dried agglomerated precipitate was calcined at 800°C in conventional furnace for an hour. The influence of calcium oxide concentration and pH on the resulting precipitates was studied using BET, XRD and SEM. As result, a well-defined sub-rounded morphology of powders size of ∼41 nm was obtained with a salt concentration of 0.02 M. Finally, it can be concluded that small changes in the reaction conditions led to large changes in final size, shape and degree of aggregation of the hydroxyapatite particles.

  14. BASIC PEROXIDE PRECIPITATION METHOD OF SEPARATING PLUTONIUM FROM CONTAMINANTS

    DOEpatents

    Seaborg, G.T.; Perlman, I.

    1959-02-10

    A process is described for the separation from each other of uranyl values, tetravalent plutonium values and fission products contained in an aqueous acidic solution. First the pH of the solution is adjusted to between 2.5 and 8 and hydrogen peroxide is then added to the solution causing precipitation of uranium peroxide which carries any plutonium values present, while the fission products remain in solution. Separation of the uranium and plutonium values is then effected by dissolving the peroxide precipitate in an acidic solution and incorporating a second carrier precipitate, selective for plutonium. The plutonium values are thus carried from the solution while the uranium remains flissolved. The second carrier precipitate may be selected from among the group consisting of rare earth fluorides, and oxalates, zirconium phosphate, and bismuth lihosphate.

  15. Prediction of Altered Bile Acid Disposition Due to Inhibition of Multiple Transporters: An Integrated Approach Using Sandwich-Cultured Hepatocytes, Mechanistic Modeling, and Simulation.

    PubMed

    Guo, Cen; Yang, Kyunghee; Brouwer, Kenneth R; St Claire, Robert L; Brouwer, Kim L R

    2016-08-01

    Transporter-mediated alterations in bile acid disposition may have significant toxicological implications. Current methods to predict interactions are limited by the interplay of multiple transporters, absence of protein in the experimental system, and inaccurate estimates of inhibitor concentrations. An integrated approach was developed to predict altered bile acid disposition due to inhibition of multiple transporters using the model bile acid taurocholate (TCA). TCA pharmacokinetic parameters were estimated by mechanistic modeling using sandwich-cultured human hepatocyte data with protein in the medium. Uptake, basolateral efflux, and biliary clearance estimates were 0.63, 0.034, and 0.074 mL/min/g liver, respectively. Cellular total TCA concentrations (Ct,Cells) were selected as the model output based on sensitivity analysis. Monte Carlo simulations of TCA Ct,Cells in the presence of model inhibitors (telmisartan and bosentan) were performed using inhibition constants for TCA transporters and inhibitor concentrations, including cellular total inhibitor concentrations ([I]t,cell) or unbound concentrations, and cytosolic total or unbound concentrations. For telmisartan, the model prediction was accurate with an average fold error (AFE) of 0.99-1.0 when unbound inhibitor concentration ([I]u) was used; accuracy dropped when total inhibitor concentration ([I]t) was used. For bosentan, AFE was 1.2-1.3 using either [I]u or [I]t This difference was evaluated by sensitivity analysis of the cellular unbound fraction of inhibitor (fu,cell,inhibitor), which revealed higher sensitivity of fu,cell,inhibitor for predicting TCA Ct,Cells when inhibitors exhibited larger ([I]t,cell/IC50) values. In conclusion, this study demonstrated the applicability of a framework to predict hepatocellular bile acid concentrations due to drug-mediated inhibition of transporters using mechanistic modeling and cytosolic or cellular unbound concentrations. PMID:27233294

  16. The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Arkin, Philip; Chang, Alfred; Ferraro, Ralph; Gruber, Arnold; Janowiak, John; McNab, Alan; Rudolf, Bruno; Schneider, Udo

    1997-01-01

    The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit -satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5 deg x 2.5 deg latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.

  17. Laboratory batch experiments of the combined effects of ultrasound and air stripping in removing CCl4 and 1,1,1-TCA from water.

    PubMed

    Ayyildiz, Onder; Anderson, Paul R; Peters, Robert W

    2005-04-11

    Ultrasonic and air-stripping techniques for removal of carbon tetrachloride (CCl4) and 1,1,1-trichloroethane (1,1,1-TCA) from water were studied in batch experiments. Ultrasound (US) is effective for destroying organic compounds in aqueous solutions whereas air stripping (AS) efficiently transfers volatile compounds from the liquid to the gas phase. In simultaneous US and AS experiments, synergistic effects were observed and attributed to the effect of US on the mass transfer process. Using a photographic method, ultrasonic break up of gas bubbles and changes in gas holdup ratios were examined. In the two different gas-sparging systems studied, ultrasonic waves did not break up gas bubbles. In contrast, bubbles from the smaller porous size diffuser were coalesced due to sonication. In addition, both photographic and gas holdup experiments demonstrated that ultrasonic irradiation increased the gas holdup ratio. The enhancement observed in the removal of the compounds appeared to be due to this greater ultrasonic gas holdup ratio.

  18. Code Calibration Applied to the TCA High-Lift Model in the 14 x 22 Wind Tunnel (Simulation With and Without Model Post-Mount)

    NASA Technical Reports Server (NTRS)

    Lessard, Wendy B.

    1999-01-01

    The objective of this study is to calibrate a Navier-Stokes code for the TCA (30/10) baseline configuration (partial span leading edge flaps were deflected at 30 degs. and all the trailing edge flaps were deflected at 10 degs). The computational results for several angles of attack are compared with experimental force, moments, and surface pressures. The code used in this study is CFL3D; mesh sequencing and multi-grid were used to full advantage to accelerate convergence. A multi-grid approach was used similar to that used for the Reference H configuration allowing point-to-point matching across all the trailingedge block interfaces. From past experiences with the Reference H (ie, good force, moment, and pressure comparisons were obtained), it was assumed that the mounting system would produce small effects; hence, it was not initially modeled. However, comparisons of lower surface pressures indicated the post mount significantly influenced the lower surface pressures, so the post geometry was inserted into the existing grid using Chimera (overset grids).

  19. A systematic analysis of TCA Escherichia coli mutants reveals suitable genetic backgrounds for enhanced hydrogen and ethanol production using glycerol as main carbon source.

    PubMed

    Valle, Antonio; Cabrera, Gema; Muhamadali, Howbeer; Trivedi, Drupad K; Ratray, Nicholas J W; Goodacre, Royston; Cantero, Domingo; Bolivar, Jorge

    2015-09-01

    Biodiesel has emerged as an environmentally friendly alternative to fossil fuels; however, the low price of glycerol feed-stocks generated from the biodiesel industry has become a burden to this industry. A feasible alternative is the microbial biotransformation of waste glycerol to hydrogen and ethanol. Escherichia coli, a microorganism commonly used for metabolic engineering, is able to biotransform glycerol into these products. Nevertheless, the wild type strain yields can be improved by rewiring the carbon flux to the desired products by genetic engineering. Due to the importance of the central carbon metabolism in hydrogen and ethanol synthesis, E. coli single null mutant strains for enzymes of the TCA cycle and other related reactions were studied in this work. These strains were grown anaerobically in a glycerol-based medium and the concentrations of ethanol, glycerol, succinate and hydrogen were analysed by HPLC and GC. It was found that the reductive branch is the more relevant pathway for the aim of this work, with malate playing a central role. It was also found that the putative C4-transporter dcuD mutant improved the target product yields. These results will contribute to reveal novel metabolic engineering strategies for improving hydrogen and ethanol production by E. coli.

  20. Predicting biogeochemical calcium precipitation in landfill leachate collection systems.

    PubMed

    VanGulck, Jamie F; Rowe, R Kerry; Rittmann, Bruce E; Cooke, Andrew J

    2003-10-01

    Clogging of leachate collection systems within municipal solid waste landfills can result in greater potential for contaminants to breach the landfill barrier system. The primary cause of clogging is calcium carbonate (CaCO3(s)) precipitation from leachate and its accumulation within the pore space of the drainage medium. CaCO3(s) precipitation is caused by the anaerobic fermentation of volatile fatty acids (VFAs), which adds carbonate to and raises the pH of the leachate. An important relationship in modeling clogging in leachate collections systems is a yield coefficient that relates microbial fermentation of VFAs to precipitation of calcium carbonate. This paper develops a new, mechanistically based yield coefficient, called the carbonic acid yield coefficient (Y(H)), which relates the carbonic acid (H2CO3) produced from microbial fermentation of acetate, propionate, and butyrate to calcium precipitation. The empirical values of Y(H) were computed from the changes in acetate, propionate, butyrate, and calcium concentrations in leachate as it permeated through gravel-size material. The theoretical and empirical results show that the primary driver of CaCO3(s) precipitation is acetate fermentation. Additionally, other non-calcium cations (e.g., iron and magnesium) precipitated with carbonate (CO3(2-)) when present in the leachate. A common yield between total cations bound to CO3(2-) and H2CO3 produced, called the calcium carbonate yield coefficient (Yc), can reconcile the empirical yield coefficient for synthetic and actual leachates.

  1. [Calcium carbonate precipitation in UASB reactors with different substrates].

    PubMed

    Yang, Shu-Cheng; He, Yan-Ling; Zhang, Peng-Xiang; Liu, Yong-Hong; Wang, Dong-Qi; Yang, Jing

    2009-03-15

    Two lab scale upflow anaerobic sludge bed (UASB) reactors were operated at an organic loading rate of COD 9 kg x (m3 x d)(-1) to treat two kinds of calcium containing wastewaters, one of which took acetic acid as substrate and for the other, glucose and soluble starch were the substrate. Both the wastewaters contained 800 mg x L(-1) Ca+. Precipitation of calcium carbonate in the reactors was observed. The results showed that the kind of substrate had great influence on calcium carbonate precipitation. In the reactor treating acetic acid containing wastewater, a maximum calcium precipitation rate of 65% was achieved and an average rate of about 25% was then maintained. In contrast, the calcium precipitation rate for the glucose and soluble starch containing wastewater was only about 7.5%. It was also found that substantial precipitation only occurred 30 days after the reactor were operated for both of the wastewaters. After 180 days of operation, the ash content of the sludge in the reactors increased from about 10% to 70% for the acetic acid containing wastewater and 30% for the other. However, the increase of ash content had no negative influence on the COD removal efficiency, which was kept at about 90% throughout the experimental period. By the SEM it was inferred that the different substrates caused the differences of the granular sludge microstructure, leading to the diversity of calcium carbonate precipitation in the two reactors.

  2. Systems-level metabolic flux profiling elucidates a complete, bifurcated tricarboxylic acid cycle in Clostridium acetobutylicum.

    PubMed

    Amador-Noguez, Daniel; Feng, Xiao-Jiang; Fan, Jing; Roquet, Nathaniel; Rabitz, Herschel; Rabinowitz, Joshua D

    2010-09-01

    Obligatory anaerobic bacteria are major contributors to the overall metabolism of soil and the human gut. The metabolic pathways of these bacteria remain, however, poorly understood. Using isotope tracers, mass spectrometry, and quantitative flux modeling, here we directly map the metabolic pathways of Clostridium acetobutylicum, a soil bacterium whose major fermentation products include the biofuels butanol and hydrogen. While genome annotation suggests the absence of most tricarboxylic acid (TCA) cycle enzymes, our results demonstrate that this bacterium has a complete, albeit bifurcated, TCA cycle; oxaloacetate flows to succinate both through citrate/alpha-ketoglutarate and via malate/fumarate. Our investigations also yielded insights into the pathways utilized for glucose catabolism and amino acid biosynthesis and revealed that the organism's one-carbon metabolism is distinct from that of model microbes, involving reversible pyruvate decarboxylation and the use of pyruvate as the one-carbon donor for biosynthetic reactions. This study represents the first in vivo characterization of the TCA cycle and central metabolism of C. acetobutylicum. Our results establish a role for the full TCA cycle in an obligatory anaerobic organism and demonstrate the importance of complementing genome annotation with isotope tracer studies for determining the metabolic pathways of diverse microbes.

  3. An ATP and Oxalate Generating Variant Tricarboxylic Acid Cycle Counters Aluminum Toxicity in Pseudomonas fluorescens

    PubMed Central

    Singh, Ranji; Lemire, Joseph; Mailloux, Ryan J.; Chénier, Daniel; Hamel, Robert; Appanna, Vasu D.

    2009-01-01

    Although the tricarboxylic acid (TCA) cycle is essential in almost all aerobic organisms, its precise modulation and integration in global cellular metabolism is not fully understood. Here, we report on an alternative TCA cycle uniquely aimed at generating ATP and oxalate, two metabolites critical for the survival of Pseudomonas fluorescens. The upregulation of isocitrate lyase (ICL) and acylating glyoxylate dehydrogenase (AGODH) led to the enhanced synthesis of oxalate, a dicarboxylic acid involved in the immobilization of aluminum (Al). The increased activity of succinyl-CoA synthetase (SCS) and oxalate CoA-transferase (OCT) in the Al-stressed cells afforded an effective route to ATP synthesis from oxalyl-CoA via substrate level phosphorylation. This modified TCA cycle with diminished efficacy in NADH production and decreased CO2-evolving capacity, orchestrates the synthesis of oxalate, NADPH, and ATP, ingredients pivotal to the survival of P. fluorescens in an Al environment. The channeling of succinyl-CoA towards ATP formation may be an important function of the TCA cycle during anaerobiosis, Fe starvation and O2-limited conditions. PMID:19809498

  4. Effective Assimilation of Global Precipitation

    NASA Astrophysics Data System (ADS)

    Lien, G.; Kalnay, E.; Miyoshi, T.; Huffman, G. J.

    2012-12-01

    Assimilating precipitation observations by modifying the moisture and sometimes temperature profiles has been shown successful in forcing the model precipitation to be close to the observed precipitation, but only while the assimilation is taking place. After the forecast start, the model tends to "forget" the assimilation changes and lose their extra skill after few forecast hours. This suggests that this approach is not an efficient way to modify the potential vorticity field, since this is the variable that the model would remember. In this study, the ensemble Kalman filter (EnKF) method is used to effectively change the potential vorticity field by allowing ensemble members with better precipitation to receive higher weights. In addition to using an EnKF, two other changes in the precipitation assimilation process are proposed to solve the problems related to the highly non-Gaussian nature of the precipitation variable: a) transform precipitation into a Gaussian distribution based on its climatological distribution, and b) only assimilate precipitation at the location where some ensemble members have positive precipitation. The idea is first tested by the observing system simulation experiments (OSSEs) using SPEEDY, a simplified but realistic general circulation model. When the global precipitation is assimilated in addition to conventional rawinsonde observations, both the analyses and the medium range forecasts are significantly improved as compared to only having rawinsonde observations. The improvement is much reduced when only modifying the moisture field with the same approach, which shows the importance of the error covariance between precipitation and all other model variables. The effect of precipitation assimilation is larger in the Southern Hemisphere than that in the Northern Hemisphere because the Northern Hemisphere analyses are already accurate as a result of denser rawinsonde stations. Assimilation of precipitation using a more comprehensive

  5. Influence of chemical composition of precipitation on migration of radioactive caesium in natural soils.

    PubMed

    Thørring, H; Skuterud, L; Steinnes, E

    2014-08-01

    The aim of the present work was to study the impact of the chemical composition of precipitation on radiocaesium mobility in natural soil. This was done through column studies. Three types of precipitation regimes were studied, representing a natural range found in Norway: Acidic precipitation (southernmost part of the country); precipitation rich in marine cations (highly oceanic coastal areas); and low concentrations of sea salts (slightly continental inland areas). After 50 weeks and a total precipitation supply of ∼10 000 L m(-2) per column, results indicate that acidic precipitation increased the mobility of (134)Cs added during the experiment. However, depth distribution of already present Chernobyl fallout (137)Cs was not significantly affected by the chemical composition of precipitation. PMID:24704765

  6. Influence of chemical composition of precipitation on migration of radioactive caesium in natural soils.

    PubMed

    Thørring, H; Skuterud, L; Steinnes, E

    2014-08-01

    The aim of the present work was to study the impact of the chemical composition of precipitation on radiocaesium mobility in natural soil. This was done through column studies. Three types of precipitation regimes were studied, representing a natural range found in Norway: Acidic precipitation (southernmost part of the country); precipitation rich in marine cations (highly oceanic coastal areas); and low concentrations of sea salts (slightly continental inland areas). After 50 weeks and a total precipitation supply of ∼10 000 L m(-2) per column, results indicate that acidic precipitation increased the mobility of (134)Cs added during the experiment. However, depth distribution of already present Chernobyl fallout (137)Cs was not significantly affected by the chemical composition of precipitation.

  7. What Is Acid Rain?

    ERIC Educational Resources Information Center

    Likens, Gene E.

    2004-01-01

    Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.…

  8. Extraction, purification, methylation and GC-MS analysis of short-chain carboxylic acids for metabolic flux analysis.

    PubMed

    Tivendale, Nathan D; Jewett, Erin M; Hegeman, Adrian D; Cohen, Jerry D

    2016-08-15

    Dynamic metabolic flux analysis requires efficient and effective methods for extraction, purification and analysis of a plethora of naturally-occurring compounds. One area of metabolism that would be highly informative to study using metabolic flux analysis is the tricarboxylic acid (TCA) cycle, which consists of short-chain carboxylic acids. Here, we describe a newly-developed method for extraction, purification, derivatization and analysis of short-chain carboxylic acids involved in the TCA cycle. The method consists of snap-freezing the plant material, followed by maceration and a 12-15h extraction at -80 °C. The extracts are then subject to reduction (to stabilize β-keto acids), purified by strong anion exchange solid phase extraction and methylated with methanolic HCl. This method could also be readily adapted to quantify many other short-chain carboxylic acids.

  9. Extraction, purification, methylation and GC-MS analysis of short-chain carboxylic acids for metabolic flux analysis.

    PubMed

    Tivendale, Nathan D; Jewett, Erin M; Hegeman, Adrian D; Cohen, Jerry D

    2016-08-15

    Dynamic metabolic flux analysis requires efficient and effective methods for extraction, purification and analysis of a plethora of naturally-occurring compounds. One area of metabolism that would be highly informative to study using metabolic flux analysis is the tricarboxylic acid (TCA) cycle, which consists of short-chain carboxylic acids. Here, we describe a newly-developed method for extraction, purification, derivatization and analysis of short-chain carboxylic acids involved in the TCA cycle. The method consists of snap-freezing the plant material, followed by maceration and a 12-15h extraction at -80 °C. The extracts are then subject to reduction (to stabilize β-keto acids), purified by strong anion exchange solid phase extraction and methylated with methanolic HCl. This method could also be readily adapted to quantify many other short-chain carboxylic acids. PMID:27348709

  10. Inducing mineral precipitation in groundwater by addition of phosphate

    PubMed Central

    2011-01-01

    Background Induced precipitation of phosphate minerals to scavenge trace elements from groundwater is a potential remediation approach for contaminated aquifers. The success of engineered precipitation schemes depends on the particular phases generated, their rates of formation, and their long term stability. The purpose of this study was to examine the precipitation of calcium phosphate minerals under conditions representative of a natural groundwater. Because microorganisms are present in groundwater, and because some proposed schemes for phosphate mineral precipitation rely on stimulation of native microbial populations, we also tested the effect of bacterial cells (initial densities of 105 and 107 mL-1) added to the precipitation medium. In addition, we tested the effect of a trace mixture of propionic, isovaleric, formic and butyric acids (total concentration 0.035 mM). Results The general progression of mineral precipitation was similar under all of the study conditions, with initial formation of amorphous calcium phosphate, and transformation to poorly crystalline hydroxylapatite (HAP) within one week. The presence of the bacterial cells appeared to delay precipitation, although by the end of the experiments the overall extent of precipitation was similar for all treatments. The stoichiometry of the final precipitates as well as Rietveld structure refinement using x-ray diffraction data indicated that the presence of organic acids and bacterial cells resulted in an increasing a and decreasing c lattice parameter, with the higher concentration of cells resulting in the greatest distortion. Uptake of Sr into the solids was decreased in the treatments with cells and organic acids, compared to the control. Conclusions Our results suggest that the minerals formed initially during an engineered precipitation application for trace element sequestration may not be the ones that control long-term immobilization of the contaminants. In addition, the presence of

  11. Inducing Mineral Precipitation in Groundwater by Addition of Phosphate

    SciTech Connect

    Karen E. Wright; Yoshiko Fujita; Thomas Hartmann; Mark Conrad

    2011-10-01

    Induced precipitation of phosphate minerals to scavenge trace metals and radionuclides from groundwater is a potential remediation approach for contaminated aquifers. Phosphate minerals can sequester trace elements by primary mineral formation, solid solution formation and/or adsorption, and they are poorly soluble under many environmental conditions, making them attractive for long-term sustainable remediation. The success of such engineered schemes will depend on the particular mineral phases generated, their rates of formation, and their long term stability. The purpose of this study was to examine the precipitation of calcium phosphate minerals under conditions representative of a natural groundwater. Because microorganisms are present in groundwater, and because some proposed schemes for induced phosphate mineral precipitation rely on the stimulation of native groundwater populations, we also tested the effect of bacterial cells (initial densities of 105 and 107 ml-1) within the precipitation medium. We also tested the effect of a trace mixture of propionic, isovaleric, formic and butyric acids (total concentration 0.035 mM). The experiments showed that the general progression of mineral precipitation was similar under all of the conditions, with initial formation of amorphous calcium carbonate, and transformation to poorly crystalline hydroxyapatite (HAP) by the end of the week-long experiments. The presence of the bacterial cells appeared to delay precipitation, although by the end of 7 days the overall extent of precipitation was similar for all of the treatments. The stoichiometry of the final precipitates as well as results of Rietveld refinement of x-ray diffraction data indicated that the treatments including organic acids and bacterial cells resulted in increased distortion of the HAP crystal lattice, with the higher concentration of cells resulting in the greatest distortion. Uptake of Sr into the phosphate minerals was decreased in the treatments

  12. Tricarboxylic acid cycle intermediate pool size: functional importance for oxidative metabolism in exercising human skeletal muscle.

    PubMed

    Bowtell, Joanna L; Marwood, Simon; Bruce, Mark; Constantin-Teodosiu, Dumitru; Greenhaff, Paul L

    2007-01-01

    The tricarboxylic acid (TCA) cycle is the major final common pathway for oxidation of carbohydrates, lipids and some amino acids, which produces reducing equivalents in the form of nicotinamide adenine dinucleotide and flavin adenine dinucleotide that result in production of large amounts of adenosine triphosphate (ATP) via oxidative phosphorylation. Although regulated primarily by the products of ATP hydrolysis, in particular adenosine diphosphate, the rate of delivery of reducing equivalents to the electron transport chain is also a potential regulatory step of oxidative phosphorylation. The TCA cycle is responsible for the generation of approximately 67% of all reducing equivalents per molecule of glucose, hence factors that influence TCA cycle flux will be of critical importance for oxidative phosphorylation. TCA cycle flux is dependent upon the supply of acetyl units, activation of the three non-equilibrium reactions within the TCA cycle, and it has been suggested that an increase in the total concentration of the TCA cycle intermediates (TCAi) is also necessary to augment and maintain TCA cycle flux during exercise. This article reviews the evidence of the functional importance of the TCAi pool size for oxidative metabolism in exercising human skeletal muscle. In parallel with increased oxidative metabolism and TCA cycle flux during exercise, there is an exercise intensity-dependent 4- to 5-fold increase in the concentration of the TCAi. TCAi concentration reaches a peak after 10-15 minutes of exercise, and thereafter tends to decline. This seems to support the suggestion that the concentration of TCAi may be of functional importance for oxidative phosphorylation. However, researchers have been able to induce dissociations between TCAi pool size and oxidative energy provision using a variety of nutritional, pharmacological and exercise interventions. Brief periods of endurance training (5 days or 7 weeks) have been found to result in reduced TCAi pool

  13. Tricarboxylic acid cycle intermediate pool size: functional importance for oxidative metabolism in exercising human skeletal muscle.

    PubMed

    Bowtell, Joanna L; Marwood, Simon; Bruce, Mark; Constantin-Teodosiu, Dumitru; Greenhaff, Paul L

    2007-01-01

    The tricarboxylic acid (TCA) cycle is the major final common pathway for oxidation of carbohydrates, lipids and some amino acids, which produces reducing equivalents in the form of nicotinamide adenine dinucleotide and flavin adenine dinucleotide that result in production of large amounts of adenosine triphosphate (ATP) via oxidative phosphorylation. Although regulated primarily by the products of ATP hydrolysis, in particular adenosine diphosphate, the rate of delivery of reducing equivalents to the electron transport chain is also a potential regulatory step of oxidative phosphorylation. The TCA cycle is responsible for the generation of approximately 67% of all reducing equivalents per molecule of glucose, hence factors that influence TCA cycle flux will be of critical importance for oxidative phosphorylation. TCA cycle flux is dependent upon the supply of acetyl units, activation of the three non-equilibrium reactions within the TCA cycle, and it has been suggested that an increase in the total concentration of the TCA cycle intermediates (TCAi) is also necessary to augment and maintain TCA cycle flux during exercise. This article reviews the evidence of the functional importance of the TCAi pool size for oxidative metabolism in exercising human skeletal muscle. In parallel with increased oxidative metabolism and TCA cycle flux during exercise, there is an exercise intensity-dependent 4- to 5-fold increase in the concentration of the TCAi. TCAi concentration reaches a peak after 10-15 minutes of exercise, and thereafter tends to decline. This seems to support the suggestion that the concentration of TCAi may be of functional importance for oxidative phosphorylation. However, researchers have been able to induce dissociations between TCAi pool size and oxidative energy provision using a variety of nutritional, pharmacological and exercise interventions. Brief periods of endurance training (5 days or 7 weeks) have been found to result in reduced TCAi pool

  14. Pesticides in Iowa precipitation

    USGS Publications Warehouse

    Nations, B.K.; Hallberg, G.R.

    1992-01-01

    Rainfall was sampled for pesticides to assess their occurrence in precipitation and potential impacts on water resources. Three areas in Iowa were sampled; two localities were in rural settings, and a third in an urban area. Fourteen pesticides, including ten herbicides and four insecticides, were detected from October 1987 through September 1990. Atrazine, alachlor, cyanazine, and metolachlor were the most commonly detected, with one or more of these four herbicides found in almost every rainfall sample during the growing season. Concentrations of individual pesticides ranged from 0.1 ??g L-1 to 40.0 ??g L-1, with most detections under 1.0 ??g L-1. Pesticide detections in rainfall began in April and ended in July or August, probably related to the timing of chemical application and greater volatilization rates during warmer weather. Samples from the urban site had detections of the same agricultural chemicals found at the rural sites, but in lesser quantities. In addition to the commonly detected herbicides, three of the four insecticides detected in rainfall were only found in urban samples. Two of these have urban as well as agricultural uses. Some variation of pesticide detections were seen at the three sampling localities, related to regional and local use patterns. Concentrations were greater at sampling sites near fields where pesticides are applied, suggesting that local volatilization and distance of transport affect the concentrations in rainfall. Pesticide concentrations were highest at the beginning of a rainfall event with concentrations becoming lower in samples taken later in the event.

  15. Highly sensitive amperometric sensor for micromolar detection of trichloroacetic acid based on multiwalled carbon nanotubes and Fe(II)-phtalocyanine modified glassy carbon electrode.

    PubMed

    Kurd, Masoumeh; Salimi, Abdollah; Hallaj, Rahman

    2013-04-01

    A highly sensitive electrochemical sensor for the detection of trichloroacetic acid (TCA) is developed by subsequent immobilization of phthalocyanine (Pc) and Fe(II) onto multiwalled carbon nanotubes (MWCNTs) modified glassy carbon (GC) electrode. The GC/MWCNTs/Pc/Fe(II) electrode showed a pair of well-defined and nearly reversible redox couple correspondent to (Fe(III)Pc/Fe(II)Pc) with surface-confined characteristics. The surface coverage (Γ) and heterogeneous electron transfer rate constant (ks) of immobilized Fe(II)-Pc were calculated as 1.26×10(-10) mol cm(-2) and 28.13 s(-1), respectively. Excellent electrocatalytic activity of the proposed GC/MWCNTs/Pc/Fe(II) system toward TCA reduction has been indicated and the three consequent irreversible peaks for electroreduction of CCl3COOH to CH3COOH have been clearly seen. The observed chronoamperometric currents are linearly increased with the concentration of TCA at concentration range up to 20mM. Detection limit and sensitivity of the modified electrode were 2.0 μM and 0.10 μA μM(-1) cm(-2), respectively. The applicability of the sensor for TCA detection in real samples was tested. The obtained results suggest that the proposed system can serve as a promising electrochemical platform for TCA detection.

  16. A Comparison between the Effects of Glucantime, Topical Trichloroacetic Acid 50% plus Glucantime, and Fractional Carbon Dioxide Laser plus Glucantime on Cutaneous Leishmaniasis Lesions

    PubMed Central

    Jaffary, Fariba; Nilforoushzadeh, Mohammad Ali; Siadat, Amirhossein; Haftbaradaran, Elaheh; Ansari, Nazli; Ahmadi, Elham

    2016-01-01

    Background. Cutaneous leishmaniasis is an endemic disease in Iran. Pentavalent antimonial drugs have been the first line of therapy in cutaneous leishmaniasis for many years. However, the cure rate of these agents is still not favorable. This study was carried out to compare the efficacies of intralesional glucantime with topical trichloroacetic acid 50% (TCA 50%) + glucantime and fractional carbon dioxide laser + glucantime in the treatment of cutaneous leishmaniasis. Methods. A total of 90 patients were randomly divided into three groups of 30 to be treated with intralesional injection of glucantime, a combination of topical TCA 50% and glucantime, or a combination of fractional laser and glucantime. The overall clinical improvement and changes in sizes of lesions and scars were assessed and compared among three groups. Results. The mean duration of treatment was 6.1 ± 2.1 weeks in all patients (range: 2–12 weeks) and 6.8 ± 1.7, 5.2 ± 1.0, and 6.3 ± 3.0 weeks in glucantime, topical TCA plus glucantime, and fractional laser plus glucantime groups, respectively (P = 0.011). Complete improvement was observed in 10 (38.5%), 27 (90%), and 20 (87%) patients of glucantime, glucantime + TCA, and glucantime + laser groups, respectively (P < 0.001). Conclusion. Compared to glucantime alone, the combination of intralesional glucantime and TCA 50% or fractional CO2 laser had significantly higher and faster cure rate in patients with cutaneous leishmaniasis. PMID:27148363

  17. Precipitation in the Solar System

    ERIC Educational Resources Information Center

    McIntosh, Gordon

    2007-01-01

    As an astronomy instructor, I am always looking for commonly observed Earthly experiences to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote a short TPT article on frost. This paper is on the related phenomena of precipitation. Precipitation, so common on most of the Earth's…

  18. Resistivity Problems in Electrostatic Precipitation

    ERIC Educational Resources Information Center

    White, Harry J.

    1974-01-01

    The process of electrostatic precipitation has ever-increasing application in more efficient collection of fine particles from industrial air emissions. This article details a large number of new developments in the field. The emphasis is on high resistivity particles which are a common cause of poor precipitator performance. (LS)

  19. Precipitation Process and Apparatus Therefor

    DOEpatents

    Stang, Jr, L C

    1950-12-05

    This invention concerns an apparatus for remotely-controlled precipitation and filtration operations. Liquid within a precipitation chamber is maintained above a porous member by introducing air beneath the member; pressure beneath the porous member is reduced to suck the liquid through the member and effect filtration.

  20. Encoding information into precipitation structures

    NASA Astrophysics Data System (ADS)

    Martens, Kirsten; Bena, Ioana; Droz, Michel; Rácz, Zoltan

    2008-12-01

    Material design at submicron scales would be profoundly affected if the formation of precipitation patterns could be easily controlled. It would allow the direct building of bulk structures, in contrast to traditional techniques which consist of removing material in order to create patterns. Here, we discuss an extension of our recent proposal of using electrical currents to control precipitation bands which emerge in the wake of reaction fronts in A+ + B- → C reaction-diffusion processes. Our main result, based on simulating the reaction-diffusion-precipitation equations, is that the dynamics of the charged agents can be guided by an appropriately designed time-dependent electric current so that, in addition to the control of the band spacing, the width of the precipitation bands can also be tuned. This makes straightforward the encoding of information into precipitation patterns and, as an amusing example, we demonstrate the feasibility by showing how to encode a musical rhythm.

  1. [Seasonal variations of HCOOH and HCHO in precipitation in Guiyang].

    PubMed

    Xu, Gang; Li, Xin-Qing; Huang, Rong-Sheng; Jiang, Wei; Ding, Wen-Ci

    2008-07-01

    Formic acid and formaldehyde are the important and ubiquitous chemical constituents in the atmosphere. Precipitation in Guiyang, the capital city of Guizhou province, was analyzed with ICS-90 ion chromatography for their concentration changes in a year. The volume mean weight average concentration (VMWA) is (13.27 +/- 25.92) micromol/L and (7.89 +/- 8.92) micromol/L for formic acid and formaldehyde, respectively. Both species demonstrated higher concentration during winter-half-year than the summer-half-year. Day-time concentration is higher than the night-time, the diurnal variations for both chemical constituents indicate the sources from human activities and photochemical reactions. Regression analysis of concentration vs precipitation volume and deposition amount vs precipitation volume reveals that dilution and scavenging of precipitation in the below-cloud process are responsible for the changes of the concentrations. The significant correlation between formic acid and formaldehyde suggests similar sources or reaction relationship. The known aqueous oxidation of formaldehyde, however, can not be used to explain the link of the two compounds, and thus should not be the major source of formic acid in Guiyang, Instead, photochemical reactions of unsaturated hydrocarbons (natural or anthropological) were the major sources for formic acid and formaldehyde.

  2. Estimating background precipitation quality from network data.

    PubMed

    Hicks, B B; Artz, R S

    1992-01-01

    Assessments of the relative merits of alternative acid-rain control strategies revolve around considerations of potential benefit per unit effort and/or cost. A question that often arises concerns the changes in deposition that would follow if all industrial (or societal) emissions were eliminated, in which case precipitation chemistry would be dominated by emissions from natural sources. Estimates of the 'natural background' of precipitation chemistry can be based on (a) measurements made at distant locations, (b) reducing emissions to zero in numerical simulations, or (c) examinations of existing data. Each alternative is flawed because (a) of the assumption that natural emissions in one location are like those in another, (b) no existing model contains descriptions of chemical processes involving all of the chemical species of importance, and (c) all contemporary data records or relevance are affected by precisely the emissions we wish to reduce. Here, the third alternative is explored in detail, using event precipitation chemistry data from North America. The analysis reveals a background pH level that varies from site to site, but always lies in the range 5.0-5.3.

  3. Acid rain

    SciTech Connect

    Bess, F.D.

    1980-01-01

    The acid rain problem in the northeastern U.S. has been growing in severity and geographical areas affected. Acid rain has damaged, or will result in damage to visibility, physical structures and materials, aquatic life, timber, crops, and soils. The principal causes of acid rain in the northeastern U.S. are sulfur oxide and nitrogen oxide emissions from large power plants and smelters in the Ohio River Valley. Immediate corrective action and appropriate research are needed to reduce acid precipitation. Short-term programs that will define the rate of environmental deterioration, remaining environmental capacity to resist sudden deterioration, mechanisms of acid rain formation, and costs of various control options must be developed. (3 maps, 13 references, 1 table)

  4. The Changing Character of Precipitation.

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Dai, Aiguo; Rasmussen, Roy M.; Parsons, David B.

    2003-09-01

    From a societal, weather, and climate perspective, precipitation intensity, duration, frequency, and phase are as much of concern as total amounts, as these factors determine the disposition of precipitation once it hits the ground and how much runs off. At the extremes of precipitation incidence are the events that give rise to floods and droughts, whose changes in occurrence and severity have an enormous impact on the environment and society. Hence, advancing understanding and the ability to model and predict the character of precipitation is vital but requires new approaches to examining data and models. Various mechanisms, storms and so forth, exist to bring about precipitation. Because the rate of precipitation, conditional on when it falls, greatly exceeds the rate of replenishment of moisture by surface evaporation, most precipitation comes from moisture already in the atmosphere at the time the storm begins, and transport of moisture by the storm-scale circulation into the storm is vital. Hence, the intensity of precipitation depends on available moisture, especially for heavy events. As climate warms, the amount of moisture in the atmosphere, which is governed by the Clausius- Clapeyron equation, is expected to rise much faster than the total precipitation amount, which is governed by the surface heat budget through evaporation. This implies that the main changes to be experienced are in the character of precipitation: increases in intensity must be offset by decreases in duration or frequency of events. The timing, duration, and intensity of precipitation can be systematically explored via the diurnal cycle, whose correct simulation in models remains an unsolved challenge of vital importance in global climate change. Typical problems include the premature initiation of convection, and precipitation events that are too light and too frequent. These challenges in observations, modeling, and understanding precipitation changes are being taken up in the NCAR

  5. Dye-promoted precipitation of serum proteins. Mechanism and application.

    PubMed

    Birkenmeier, G; Kopperschläger, G

    1991-11-01

    Immobilized dyes have been used primarily for purification of nucleotide dependent enzymes and proteins from plasma and other sources. Due to their low costs, high protein binding capacity and resistance to degradation dyes bear the potential as ligand for affinity separation of proteins on a large scale. In this paper dyes have been used for precipitation of proteins. Using albumin, prealbumin, alpha 1-acid glycoprotein and immunoglobulin G as model proteins we could demonstrate that dye-promoted precipitation depends on several factors which include the structure of the dye, the pH of the solution, the dye/protein molar ratio and the intrinsic properties of the proteins. It revealed that most of the dyes tested were endowed with the precipitating potential. The efficacy of precipitation was found to increase with the complexity of the dye structure. However, the amount of a dye required for total precipitation was found to be different for a given protein. Electrostatic as well as hydrophobic forces are involved in the mechanism of precipitation. It was demonstrated that by optimizing the conditions, mixtures of proteins can be resolved by dye-promoted precipitation. The high sensitivity of the reaction offers the possibility of using this method for rapid concentration of very diluted protein solutions. PMID:1367693

  6. Estimation of continental precipitation recycling

    SciTech Connect

    Brubaker, K.L.; Entekhabi, D.; Eagleson, P.S. )

    1993-06-01

    The total amount of water that precipitates on large continental regions is supplied by two mechanisms: (1) advection from the surrounding areas external to the region and (2) evaporation and transpiration from the land surface within the region. The latter supply mechanism is tantamount to the recycling of precipitation over the Continental area. The degree to which regional precipitation is supplied by recycled moisture is a potentially significant climate feedback mechanism and land surface-atmosphere interaction, which may contribute to the persistence and intensification of droughts. Gridded data on observed wind and humidity in the global atmosphere are used to determine the convergence of atmospheric water vapor over continental regions. A simplified model of the atmospheric moisture over continents and simultaneous estimates of regional precipitation are employed to estimate, for several large continental regions, the fraction of precipitation that is locally derived. The results indicate that the contribution of regional evaporation to regional precipitation varies substantially with location and season. For the regions studied, the ratio of locally contributed to total monthly precipitation generally lies between 0. 10 and 0.30 but is as high as 0.40 in several cases. 48 refs., 7 figs., 4 tabs.

  7. Estimation of continental precipitation recycling

    NASA Technical Reports Server (NTRS)

    Brubaker, Kaye L.; Entekhabi, Dara; Eagleson, P. S.

    1993-01-01

    The total amount of water that precipitates on large continental regions is supplied by two mechanisms: 1) advection from the surrounding areas external to the region and 2) evaporation and transpiration from the land surface within the region. The latter supply mechanism is tantamount to the recycling of precipitation over the continental area. The degree to which regional precipitation is supplied by recycled moisture is a potentially significant climate feedback mechanism and land surface-atmosphere interaction, which may contribute to the persistence and intensification of droughts. Gridded data on observed wind and humidity in the global atmosphere are used to determine the convergence of atmospheric water vapor over continental regions. A simplified model of the atmospheric moisture over continents and simultaneous estimates of regional precipitation are employed to estimate, for several large continental regions, the fraction of precipitation that is locally derived. The results indicate that the contribution of regional evaporation to regional precipitation varies substantially with location and season. For the regions studied, the ratio of locally contributed to total monthly precipitation generally lies between 0. 10 and 0.30 but is as high as 0.40 in several cases.

  8. Studies of heat precipitable immunoglobulins

    PubMed Central

    Patterson, R.; Roberts, Mary; Pruzansky, J. J.

    1970-01-01

    The nature of the heat precipitation of 3 mononoclonal heat labile immunoglobulins was studied. These included 2 γG pyroglobulins and one γM pyroglobulin. Thermoprecipitable activity of both γG pyroglobulins could be localized to their heavy chains and to the Fab fragments of one of them. Heat precipitability of the γM paraprotein required the presence of the intact γM molecule since 7S subunits did not precipitate. The thermal precipitates appeared to result from intramolecular or intermolecular reactions with the formation of strong covalent bonds rather than weak non-covalent bonds. The importance of disulphide bonding was excluded in the precipitation of both γG but not in the γM pyroglobulins. Heat precipitation of the monoclonal γM resulted in coprecipitation of other proteins, particularly γG globulin, which suggested a specific type of reaction with this immunoglobulin. The interaction of the γM pyroglobulin, normal γG and heat produced an irreversible precipitate. ImagesFig. 1 PMID:4099668

  9. Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K.

    PubMed

    Huh, Won Bum; Kim, Jong-Eun; Kang, Young-Gyu; Park, Gaeun; Lim, Tae-gyu; Kwon, Jung Yeon; Song, Da Som; Jeong, Eun Hee; Lee, Charles C; Son, Joe Eun; Seo, Sang Gwon; Lee, Eunjung; Kim, Jong Rhan; Lee, Chang Yong; Park, Jun Seong; Lee, Ki Won

    2015-01-01

    Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression.

  10. Brown Pine Leaf Extract and Its Active Component Trans-Communic Acid Inhibit UVB-Induced MMP-1 Expression by Targeting PI3K

    PubMed Central

    Park, Gaeun; Lim, Tae-gyu; Kwon, Jung Yeon; Song, Da Som; Jeong, Eun Hee; Lee, Charles C.; Son, Joe Eun; Seo, Sang Gwon; Lee, Eunjung; Kim, Jong Rhan; Lee, Chang Yong; Park, Jun Seong; Lee, Ki Won

    2015-01-01

    Japanese red pine (Pinus densiflora) is widely present in China, Japan, and Korea. Its green pine leaves have traditionally been used as a food as well as a coloring agent. After being shed, pine leaves change their color from green to brown within two years, and although the brown pine leaves are abundantly available, their value has not been closely assessed. In this study, we investigated the potential anti-photoaging properties of brown pine leaves for skin. Brown pine leaf extract (BPLE) inhibited UVB-induced matrix metalloproteinase-1 (MMP-1) expression to a greater extent than pine leaf extract (PLE) in human keratinocytes and a human skin equivalent model. HPLC analysis revealed that the quantity of trans-communic acid (TCA) and dehydroabietic acid (DAA) significantly increases when the pine leaf color changes from green to brown. BPLE and TCA elicited reductions in UVB-induced MMP-1 mRNA expression and activator protein-1 (AP-1) transactivation by reducing DNA binding activity of phospho-c-Jun, c-fos and Fra-1. BPLE and TCA also inhibited UVB-induced Akt phosphorylation, but not mitogen activated protein kinase (MAPK), known regulators of AP-1 transactivation. We additionally found that BPLE and TCA inhibited phosphoinositide 3-kinase (PI3K), the upstream kinase of Akt, in vitro. In summary, both BPLE and its active component TCA exhibit protective effects against UVB-induced skin aging. Taken together, these findings underline the potential for BPLE and TCA to be utilized as anti-wrinkling agents and cosmetic ingredients, as they suppress UVB-induced MMP-1 expression. PMID:26066652

  11. Regulation of leukocyte tricarboxylic acid cycle in drug-naïve Bipolar Disorder.

    PubMed

    de Sousa, Rafael T; Streck, Emilio L; Forlenza, Orestes V; Brunoni, Andre R; Zanetti, Marcus V; Ferreira, Gabriela K; Diniz, Breno S; Portela, Luis V; Carvalho, André F; Zarate, Carlos A; Gattaz, Wagner F; Machado-Vieira, Rodrigo

    2015-09-25

    Several lines of evidence suggest a role for mitochondrial dysfunction in the pathophysiology of bipolar disorder (BD). The tricarboxylic acid cycle (TCA cycle) is fundamental for mitochondrial energy production and produces substrates used in oxidative phosphorylation by the mitochondrial electron transport chain. The activity of the key TCA cycle enzymes citrate synthase, malate dehydrogenase, and succinate dehydrogenase has never been evaluated in BD. In the present study, these enzymes were assayed from leukocytes of drug-naïve BD patients in a major depressive episode (n=18) and compared to 24 age-matched healthy controls. Drug-naïve BD patients did not show differences in activities of citrate synthase (p=0.79), malate dehydrogenase (p=0.17), and succinate dehydrogenase (p=0.35) compared with healthy controls. No correlation between any TCA cycle enzyme activity and severity of depressive symptoms was observed. Overall, these data suggest that the activities of the TCA cycle enzymes are not altered in major depressive episodes of recent-onset BD, which may support the concept of illness staging and neuroprogression in BD. PMID:26297865

  12. The tricarboxylic acid cycle in Shewanella oneidensis is independent of Fur and RyhB control

    SciTech Connect

    Yang, Yunfeng; McCue, Lee Ann; Parsons, Andrea B.; Feng, Sheng; Zhou, Jizhong

    2010-10-26

    It is well established in E. coli and Vibrio cholerae that strains harboring mutations in the ferric uptake regulator gene (fur) are unable to utilize tricarboxylic acid (TCA) compounds, due to the down-regulation of key TCA cycle enzymes, such as AcnA and SdhABCD. This down-regulation is mediated by a Fur-regulated small regulatory RNA named RyhB. In this study, we showed that a fur deletion mutant of the γ-proteobacterium S. oneidensis could utilize TCA compounds. In addition, expression of the TCA cycle genes acnA and sdhA was not down-regulated in the mutant. To explore this observation further, we identified a ryhB gene in Shewanella species and demonstrated its expression experimentally. Further experiments suggested that RyhB was up-regulated in fur mutant, but that AcnA and SdhA were not controlled by RyhB. This work delineates an important difference of the Fur-RyhB regulatory cycle between S. oneidensis and other γ-proteobacteria.

  13. Regulation of leukocyte tricarboxylic acid cycle in drug-naïve Bipolar Disorder.

    PubMed

    de Sousa, Rafael T; Streck, Emilio L; Forlenza, Orestes V; Brunoni, Andre R; Zanetti, Marcus V; Ferreira, Gabriela K; Diniz, Breno S; Portela, Luis V; Carvalho, André F; Zarate, Carlos A; Gattaz, Wagner F; Machado-Vieira, Rodrigo

    2015-09-25

    Several lines of evidence suggest a role for mitochondrial dysfunction in the pathophysiology of bipolar disorder (BD). The tricarboxylic acid cycle (TCA cycle) is fundamental for mitochondrial energy production and produces substrates used in oxidative phosphorylation by the mitochondrial electron transport chain. The activity of the key TCA cycle enzymes citrate synthase, malate dehydrogenase, and succinate dehydrogenase has never been evaluated in BD. In the present study, these enzymes were assayed from leukocytes of drug-naïve BD patients in a major depressive episode (n=18) and compared to 24 age-matched healthy controls. Drug-naïve BD patients did not show differences in activities of citrate synthase (p=0.79), malate dehydrogenase (p=0.17), and succinate dehydrogenase (p=0.35) compared with healthy controls. No correlation between any TCA cycle enzyme activity and severity of depressive symptoms was observed. Overall, these data suggest that the activities of the TCA cycle enzymes are not altered in major depressive episodes of recent-onset BD, which may support the concept of illness staging and neuroprogression in BD.

  14. Staphylococcus epidermidis Polysaccharide Intercellular Adhesin Production Significantly Increases during Tricarboxylic Acid Cycle Stress

    PubMed Central

    Vuong, Cuong; Kidder, Joshua B.; Jacobson, Erik R.; Otto, Michael; Proctor, Richard A.; Somerville, Greg A.

    2005-01-01

    Staphylococcal polysaccharide intercellular adhesin (PIA) is important for the development of a mature biofilm. PIA production is increased during growth in a nutrient-replete or iron-limited medium and under conditions of low oxygen availability. Additionally, stress-inducing stimuli such as heat, ethanol, and high concentrations of salt increase the production of PIA. These same environmental conditions are known to repress tricarboxylic acid (TCA) cycle activity, leading us to hypothesize that altering TCA cycle activity would affect PIA production. Culturing Staphylococcus epidermidis with a low concentration of the TCA cycle inhibitor fluorocitrate dramatically increased PIA production without impairing glucose catabolism, the growth rate, or the growth yields. These data lead us to speculate that one mechanism by which staphylococci perceive external environmental change is through alterations in TCA cycle activity leading to changes in the intracellular levels of biosynthetic intermediates, ATP, or the redox status of the cell. These changes in the metabolic status of the bacteria result in the attenuation or augmentation of PIA production. PMID:15838022

  15. Application of talcum powder, trichloroacetic acid and silver nitrate in female rats for non-surgical sterilization: evaluation of the apoptotic pathway mRNA and miRNA genes

    PubMed Central

    Yumrutas, Onder; Kara, Murat; Atilgan, Remzi; Kavak, Salih Burcin; Bozgeyik, Ibrahim; Sapmaz, Ekrem

    2015-01-01

    There are several methods used for non-surgical sterilization in birth control including quinacrine, trichloroacetic acid (TCA), erythromycin, tetracycline, silver nitrate and talcum powder. Among these, talcum powder, TCA and silver nitrate are the most commonly used. However, the toxic and carcinogenic activities of these chemicals in ovarian tissue have been poorly elucidated. This study demonstrates the expression levels of antioxidant, apoptotic and anti-apoptotic genes after administration of talc powder, TCA and silver nitrate for non-surgical sterilization in female rat models. The expression changes of some microRNAs (miR-15b, miR-21, miR-34a and miR-98) that play key roles in the apoptosis pathway were also included. All expression analyses were evaluated with real-time PCR. The expression levels of all genes appeared to be upregulated in the talcum powder group, but the results were not statistically significant. Increased expression of Gsr and Sod1 genes was statistically significant in the talcum powder group. In TCA and silver nitrate group, expression of all genes was appeared to be elevated but only the Gsr expression was statistically significant in the TCA-administrated group; there were no statistically significant changes in the silver nitrate group. miRNA expression levels were increased in talcum powder and TCA-administrated groups, but these results were not significant. Expression levels of miR-15b, miR-21 and miR-98 in the silver nitrate group were significantly increased. Consequently, these chemicals appear to be non-carcinogenic agents for rat ovarian tissue which do not induce apoptosis. However, talcum powder and TCA can be considered as agents that are toxic to ovarian tissue. PMID:25885949

  16. Application of talcum powder, trichloroacetic acid and silver nitrate in female rats for non-surgical sterilization: evaluation of the apoptotic pathway mRNA and miRNA genes.

    PubMed

    Yumrutas, Onder; Kara, Murat; Atilgan, Remzi; Kavak, Salih Burcin; Bozgeyik, Ibrahim; Sapmaz, Ekrem

    2015-04-01

    There are several methods used for non-surgical sterilization in birth control including quinacrine, trichloroacetic acid (TCA), erythromycin, tetracycline, silver nitrate and talcum powder. Among these, talcum powder, TCA and silver nitrate are the most commonly used. However, the toxic and carcinogenic activities of these chemicals in ovarian tissue have been poorly elucidated. This study demonstrates the expression levels of antioxidant, apoptotic and anti-apoptotic genes after administration of talc powder, TCA and silver nitrate for non-surgical sterilization in female rat models. The expression changes of some microRNAs (miR-15b, miR-21, miR-34a and miR-98) that play key roles in the apoptosis pathway were also included. All expression analyses were evaluated with real-time PCR. The expression levels of all genes appeared to be upregulated in the talcum powder group, but the results were not statistically significant. Increased expression of Gsr and Sod1 genes was statistically significant in the talcum powder group. In TCA and silver nitrate group, expression of all genes was appeared to be elevated but only the Gsr expression was statistically significant in the TCA-administrated group; there were no statistically significant changes in the silver nitrate group. miRNA expression levels were increased in talcum powder and TCA-administrated groups, but these results were not significant. Expression levels of miR-15b, miR-21 and miR-98 in the silver nitrate group were significantly increased. Consequently, these chemicals appear to be non-carcinogenic agents for rat ovarian tissue which do not induce apoptosis. However, talcum powder and TCA can be considered as agents that are toxic to ovarian tissue. PMID:25885949

  17. Co-precipitation of dissolved organic matter by calcium carbonate in Pyramid Lake, Nevada

    USGS Publications Warehouse

    Leenheer, Jerry A.; Reddy, Michael M.

    2008-01-01

    Our previous research has demonstrated that dissolved organic matter (DOM) influences calcium carbonate mineral formation in surface and ground water. To better understand DOM mediation of carbonate precipitation and DOM co-precipitation and/or incorporation with carbonate minerals, we characterized the content and speciation of DOM in carbonate minerals and in the lake water of Pyramid Lake, Nevada, USA. A 400-gram block of precipitated calcium carbonate from the Pyramid Lake shore was dissolved in 8 liters of 10% acetic acid. Particulate matter not dissolved by acetic acid was removed by centrifugation. DOM from the carbonate rock was fractionated into nine portions using evaporation, dialysis, resin adsorption, and selective precipitations to remove acetic acid and inorganic constituents. The calcium carbonate rock contained 0.23% DOM by weight. This DOM was enriched in polycarboxylic proteinaceous acids and hydroxy-acids in comparison with the present lake water. DOM in lake water was composed of aliphatic, alicyclic polycarboxylic acids. These compound classes were found in previous studies to inhibit calcium carbonate precipitation. DOM fractions from the carbonate rock were 14C-age dated at about 3,100 to 3,500 years before present. The mechanism of DOM co-precipitation and/or physical incorporation in the calcium carbonate is believed to be due to formation of insoluble calcium complexes with polycarboxylic proteinaceous acids and hydroxy-acids that have moderately large stability constants at the alkaline pH of the lake. DOM co-precipitation with calcium carbonate and incorporation in precipitated carbonate minerals removes proteinaceous DOM, but nearly equivalent concentrations of neutral and acidic forms of organic nitrogen in DOM remain in solution. Calcium carbonate precipitation during lime softening pretreatment of drinking water may have practical applications for removal of proteinaceous disinfection by-product precursors.

  18. Precipitation Measurements from Space: The Global Precipitation Measurement Mission

    NASA Technical Reports Server (NTRS)

    Hou, Arthur Y.

    2007-01-01

    Water is fundamental to the life on Earth and its phase transition between the gaseous, liquid, and solid states dominates the behavior of the weather/climate/ecological system. Precipitation, which converts atmospheric water vapor into rain and snow, is central to the global water cycle. It regulates the global energy balance through interactions with clouds and water vapor (the primary greenhouse gas), and also shapes global winds and dynamic transport through latent heat release. Surface precipitation affects soil moisture, ocean salinity, and land hydrology, thus linking fast atmospheric processes to the slower components of the climate system. Precipitation is also the primary source of freshwater in the world, which is facing an emerging freshwater crisis in many regions. Accurate and timely knowledge of global precipitation is essential for understanding the behavior of the global water cycle, improving freshwater management, and advancing predictive capabilities of high-impact weather events such as hurricanes, floods, droughts, and landslides. With limited rainfall networks on land and the impracticality of making extensive rainfall measurements over oceans, a comprehensive description of the space and time variability of global precipitation can only be achieved from the vantage point of space. This presentation will examine current capabilities in space-borne rainfall measurements, highlight scientific and practical benefits derived from these observations to date, and provide an overview of the multi-national Global Precipitation Measurement (GPM) Mission scheduled to bc launched in the early next decade.

  19. Acid Rain. LC Science Tracer Bullet.

    ERIC Educational Resources Information Center

    Hollmann, Pauline, Comp.

    The term "acid rain," also called "acid precipitation," generally refers to any precipitation having a pH value of less than 5.6. This guide to the literature on acid rain in the collections of the Library of Congress is not necessarily intended to be a comprehensive bibliography. It is designed to provide the reader with a set of resources that…

  20. Silica Precipitation and Lithium Sorption

    SciTech Connect

    Jay Renew

    2015-09-20

    This file contains silica precipitation and lithium sorption data from the project. The silica removal data is corrected from the previous submission. The previous submission did not take into account the limit of detection of the ICP-MS procedure.