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Sample records for dimethylarsinic acid initiation

  1. Reduction of dimethylarsinic acid to the highly toxic dimethylarsinous acid by rats and rat liver cytosol.

    PubMed

    Németi, Balázs; Gregus, Zoltán

    2013-03-18

    Dimethylarsinic acid (DMAs(V)), the major urinary metabolite of inorganic arsenic, is weakly cytotoxic, whereas its reduced form, dimethylarsinous acid (DMAs(III)), is highly toxic. Although glutathione S-transferase omega 1 (GSTO1) and arsenic methyltransferase have been shown or thought to catalyze DMAs(V) reduction, their role in DMAs(V) reduction in vivo, or in cell extracts is uncertain. Therefore, the reduction of DMAs(V) to DMAs(III) in rats and in rat liver cytosol was studied to better understand its mechanism. To assess DMAs(V) reduction in rats, a novel procedure was devised based on following the accumulation of red blood cell (RBC)-bound dimethylarsenic (DMAs), which represents DMAs(III), in the blood of DMAs(V)-injected anesthetized rats. These studies indicated that rats reduced DMAs(V) to DMAs(III) to a significant extent, as in 90 min 31% of the injected 50 μmol/kg DMAs(V) dose was converted to DMAs(III) that was sequestered by the circulating erythrocytes. Pretreatment of rats with glutathione (GSH) depletors (phorone or BSO) delayed the elimination of DMAs(V) and the accumulation of RBC-bound DMAs, whereas the indirect methyltransferase inhibitor periodate-oxidized adenosine was without effect. Assessment of DMAs(V)-reducing activity of rat liver cytosol revealed that reduction of DMAs(V) required cytosolic protein and GSH and was inhibited by thiol reagents, GSSG and dehydroascorbate. Although thioredoxin reductase (TRR) inhibitors (aurothioglucose and Sb(III)) inhibited cytosolic DMAs(V) reduction, recombinant rat TRR plus NADPH, alone or when added to the cytosol, failed to support DMAs(V) reduction. On ultrafiltration of the cytosol through a 3 kDa filter, the reducing activity in the retentate was lost but was largely restored by NADPH. Such experiments also suggested that the reducing enzyme was larger than 100 kDa and was not GSTO1. In summary, reduction of DMAs(V) to the highly toxic DMAs(III) in rats and rat liver cytosol is a GSH

  2. CHROMATOGRAPHIC SEPARATION AND IDENTIFICATION OF PRODUCTS FROM THE REACTION OF DIMETHYLARSINIC ACID WITH HYDROGEN SULFIDE

    EPA Science Inventory

    The reaction of dimethylarsinic acid (DMAV) with hydrogen sulfide (H2S) is of biological significance and may be implicated in the overall toxicity and carcinogenicity of arsenic. The course of the reaction in aqueous phase was monitored and an initial product, dimethylthioarsin...

  3. CHROMATOGRAPHIC SEPARATION AND IDENTIFICATION OF PRODUCTS FROM THE REACTION OF DIMETHYLARSINIC ACID WITH HYDROGEN SULFIDE

    EPA Science Inventory

    The reaction of dimethylarsinic acid (DMAV) with hydrogen sulfide (H2S) is of biological significance and may be implicated in the overall toxicity and carcinogenicity of arsenic. The course of the reaction in aqueous phase was monitored and an initial product, dimethylthioarsin...

  4. Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

    USGS Publications Warehouse

    Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

    2006-01-01

    Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

  5. Dimethylarsine likely acts as a mouse-pulmonary tumor initiator via the production of dimethylarsine radical and/or its peroxy radical.

    PubMed

    Yamanaka, Kenzo; Kato, Koichi; Mizoi, Mutsumi; An, Yan; Nakanao, Masayuki; Hoshino, Mikio; Okada, Shoji

    2009-04-24

    Recent animal experiments have indicated that dimethylarsinic acid (DMA), a main metabolite of inorganic arsenic, is a complete carcinogen in the lung of mice and the urinary bladder of rats, nevertheless, no ultimate-active metabolite from DMA has been identified thus far. We have proposed that dimethylarsine ((CH(3))(2)AsH), an ultimate reductive metabolite of DMA, is excreted in the expired air of mice administered DMA, and furthermore, was easily converted into dimethylarsine radical ((CH(3))(2)As*) and dimethylarsine peroxy radical ((CH(3))(2)AsOO*) by its reaction with O(2). The aim of the present study was to elucidate the possible mode of the tumorigenic action by dimethylated arsenic. In vitro experiments using GSH reductase as a two-electron donor of dimethylarsenic-glutathione conjugate ((CH(3))(2)As-SG) and DNA adduct assay via a photochemical approach were performed. A lung tumorigenicity assay of (CH(3))(2)AsH suspended in argon-atmospheric olive oil for 5 days was also conducted in mice. The results indicated that (CH(3))(2)AsH was easily produced enzymatically from (CH(3))(2)As-SG and showed tumor-initiating action in mouse lung via the production of (CH(3))(2)As* and (CH(3))(2)AsOO* by its reaction with O(2), and that these radicals have the ability to form DNA adducts. The carcinogenicity of DMA, at least in mouse lung, could be explained based on the proposal that oral administration of DMA induces pulmonary tumors in mice, and arises from the arsine radicals produced through (CH(3))(2)AsH, which was enzymatically reduced from (CH(3))(2)As-SG.

  6. Effects of dimethylarsinic and dimethylarsinous acid on evoked synaptic potentials in hippocampal slices of young and adult rats

    SciTech Connect

    Krueger, Katharina Repges, Hendrik; Hippler, Joerg; Hartmann, Louise M.; Hirner, Alfred V.; Straub, Heidrun; Binding, Norbert; Musshoff, Ulrich

    2007-11-15

    In this study, the effects of pentavalent dimethylarsinic acid ((CH{sub 3}){sub 2}AsO(OH); DMA{sup V}) and trivalent dimethylarsinous acid ((CH{sub 3}){sub 2}As(OH); DMA{sup III}) on synaptic transmission generated by the excitatory Schaffer collateral-CA1 synapse were tested in hippocampal slices of young (14-21 day-old) and adult (2-4 month-old) rats. Both compounds were applied in concentrations of 1 to 100 {mu}mol/l. DMA{sup V} had no effect on the amplitudes of evoked fEPSPs or the induction of LTP recorded from the CA1 dendritic region either in adult or in young rats. However, application of DMA{sup III} significantly reduced the amplitudes of evoked fEPSPs in a concentration-dependent manner with a total depression following application of 100 {mu}mol/l DMA{sup III} in adult and 10 {mu}mol/l DMA{sup III} in young rats. Moreover, DMA{sup III} significantly affected the LTP-induction. Application of 10 {mu}mol/l DMA{sup III} resulted in a complete failure of the postsynaptic potentiation of the fEPSP amplitudes in slices taken both from adult and young rats. The depressant effect was not reversible after a 30-min washout of the DMA{sup III}. In slices of young rats, the depressant effects of DMA{sup III} were more pronounced than in those taken from adult ones. Compared to the (absent) effect of DMA{sup V} on synaptic transmission, the trivalent compound possesses a considerably higher neurotoxic potential.

  7. A CONCISE REVIEW OF THE TOXICITY AND CARCINOGENICITY OF DIMETHYLARSINIC ACID

    EPA Science Inventory

    Dimethylarsinic acid (DMA) has been used as an herbicide (cacodylic acid) and is the major metabolite formed after exposure to tri- (arsenite) or pentavalent (arsenate) inorganic arsenic (iAs) via ingestion or inhalation in both humans and rodents. Once viewed simply as a detoxi...

  8. A CONCISE REVIEW OF THE TOXICITY AND CARCINOGENICITY OF DIMETHYLARSINIC ACID

    EPA Science Inventory

    Dimethylarsinic acid (DMA) has been used as an herbicide (cacodylic acid) and is the major metabolite formed after exposure to tri- (arsenite) or pentavalent (arsenate) inorganic arsenic (iAs) via ingestion or inhalation in both humans and rodents. Once viewed simply as a detoxi...

  9. A PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODEL FOR intravenous and ingested DIMETHYLARSINIC ACID (DMAV) IN MICE.

    EPA Science Inventory

    A physiologically based pharmacokinetic (PBPK) model for the organoarsenical dimethylarsinic acid (DMA(V)) was developed in mice. The model was calibrated using tissue time course data from multiple tissues in mice administered DMA(V) intravenously. The final model structure was ...

  10. A PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODEL FOR intravenous and ingested DIMETHYLARSINIC ACID (DMAV) IN MICE.

    EPA Science Inventory

    A physiologically based pharmacokinetic (PBPK) model for the organoarsenical dimethylarsinic acid (DMA(V)) was developed in mice. The model was calibrated using tissue time course data from multiple tissues in mice administered DMA(V) intravenously. The final model structure was ...

  11. TISSUE DISPOSITION OF DIMETHYLARSINIC ACID IN THE MOUSE AFTER ACUTE ORAL ADMINISTRATION

    EPA Science Inventory

    TISSUE DISPOSITION OF DIMETHYLARSINIC ACID IN THE MOUSE
    AFTER ACUTE ORAL ADMINISTRATION

    Michael F. Hughes, Ph.D., Brenda C. Edwards, Carol T. Mitchell and Elaina M. Kenyon, Ph.D. United States Environmental Protection Agency, Office of Research and Development, Nation...

  12. COMPARISON OF GENE EXPRESSION IN KIDNEY AND URINARY BLADDER FROM RATS TREATED WITH DIMETHYLARSINIC ACID

    EPA Science Inventory

    Arsenic is widespread in the environment and a human carcinogen. A major metabolite of inorganic arsenic (iAs) in most species, including humans, is dimethylarsinic acid (DMA), which is also used as a pesticide. Unlike iAs, DMA induces urinary bladder tumors in rats. DMA is belie...

  13. COMPARISON OF GENE EXPRESSION IN KIDNEY AND URINARY BLADDER FROM RATS TREATED WITH DIMETHYLARSINIC ACID

    EPA Science Inventory

    Arsenic is widespread in the environment and a human carcinogen. A major metabolite of inorganic arsenic (iAs) in most species, including humans, is dimethylarsinic acid (DMA), which is also used as a pesticide. Unlike iAs, DMA induces urinary bladder tumors in rats. DMA is belie...

  14. TISSUE DISPOSITION OF DIMETHYLARSINIC ACID IN THE MOUSE AFTER ACUTE ORAL ADMINISTRATION

    EPA Science Inventory

    TISSUE DISPOSITION OF DIMETHYLARSINIC ACID IN THE MOUSE
    AFTER ACUTE ORAL ADMINISTRATION

    Michael F. Hughes, Ph.D., Brenda C. Edwards, Carol T. Mitchell and Elaina M. Kenyon, Ph.D. United States Environmental Protection Agency, Office of Research and Development, Nation...

  15. Tissue distribution and urinary excretion of dimethylated arsenic and its metabolites in dimethylarsinic acid- or arsenate-treated rats

    SciTech Connect

    Adair, Blakely M.; Moore, Tanya; Conklin, Sean D.; Creed, John T.; Wolf, Douglas C.; Thomas, David J. . E-mail: thomas.david@epa.gov

    2007-07-15

    Adult female Fisher 344 rats received drinking water containing 0, 4, 40, 100, or 200 parts per million of dimethylarsinic acid or 100 parts per million of arsenate for 14 days. Urine was collected during the last 24 h of exposure. Tissues were then taken for analysis of dimethylated and trimethylated arsenicals; urines were analyzed for these arsenicals and their thiolated derivatives. In dimethylarsinic acid-treated rats, highest concentrations of dimethylated arsenic were found in blood. In lung, liver, and kidney, concentrations of dimethylated arsenic exceeded those of trimethylated species; in urinary bladder and urine, trimethylated arsenic predominated. Dimethylthioarsinic acid and trimethylarsine sulfide were present in urine of dimethylarsinic acid-treated rats. Concentrations of dimethylated arsenicals were similar in most tissues of dimethylarsinic acid- and arsenate-treated rats, including urinary bladder which is the target for dimethylarsinic acid-induced carcinogenesis in the rat. Mean concentration of dimethylated arsenic was significantly higher (P < 0.05) in urine of dimethylarsinic acid-treated rats than in arsenate-treated rats, suggesting a difference between treatment groups in the flux of dimethylated arsenic through urinary bladder. Concentrations of trimethylated arsenic concentrations were consistently higher in dimethylarsinic acid-treated rats than in arsenate-treated rats; these differences were significant (P < 0.05) in liver, urinary bladder, and urine. Concentrations of dimethylthioarsinic acid and trimethylarsine sulfide were higher in urine from dimethylarsinic acid-treated rats than from arsenate-treated rats. Dimethylarsinic acid is extensively metabolized in the rat, yielding significant concentrations of trimethylated species and of thiolated derivatives. One or more of these metabolites could be the species causing alterations of cellular function that lead to tumors in the urinary bladder.

  16. Mechanisms of photocatalytical degradation of monomethylarsonic and dimethylarsinic acids using nanocrystalline titanium dioxide.

    PubMed

    Xu, Zhonghou; Jing, Chuanyong; Li, Fasheng; Meng, Xiaoguang

    2008-04-01

    Photodegradation mechanisms of monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) with nanocrystalline titanium dioxide under UV irradiation were investigated. In the presence of UV irradiation and 0.02 g/L TiO2, 93% MMA (initial concentration is 10 mg-As/L) was transformed into inorganic arsenate, [As(V)], after 72 h of a batch reaction. The mineralization of DMA to As(V) occurred in two steps with MMA as an intermediate product. The photodegradation rate of MMA and DMA could be described using first-order kinetics, where the apparent rate constant is 0.033/h and 0.013/h for MMA and DMA, respectively. Radical scavengers, including superoxide dimutase (SOD), sodium bicarbonate, tert-butanol, and sodium azide, were used to study the photodegradation mechanisms of MMA and DMA. The results showed that hydroxyl radicals (HO*) was the primary reactive oxygen species for the photodegradation of MMA and DMA. The methyl groups in MMA and DMAweretransformed into organic carbon, including formic acid and possibly methanol, also through photochemical reactions. The results showed that nanocrystalline TiO2 can be used for the photocatalytical degradation of MMA and DMA and subsequent removal of the converted As(V), since the high adsorption capacity of the material for inorganic arsenic species has been demonstrated in previous studies.

  17. Identifiability of PBPK models with applications to dimethylarsinic acid exposure.

    PubMed

    Garcia, Ramon I; Ibrahim, Joseph G; Wambaugh, John F; Kenyon, Elaina M; Setzer, R Woodrow

    2015-12-01

    Any statistical model should be identifiable in order for estimates and tests using it to be meaningful. We consider statistical analysis of physiologically-based pharmacokinetic (PBPK) models in which parameters cannot be estimated precisely from available data, and discuss different types of identifiability that occur in PBPK models and give reasons why they occur. We particularly focus on how the mathematical structure of a PBPK model and lack of appropriate data can lead to statistical models in which it is impossible to estimate at least some parameters precisely. Methods are reviewed which can determine whether a purely linear PBPK model is globally identifiable. We propose a theorem which determines when identifiability at a set of finite and specific values of the mathematical PBPK model (global discete identifiability) implies identifiability of the statistical model. However, we are unable to establish conditions that imply global discrete identifiability, and conclude that the only safe approach to analysis of PBPK models involves Bayesian analysis with truncated priors. Finally, computational issues regarding posterior simulations of PBPK models are discussed. The methodology is very general and can be applied to numerous PBPK models which can be expressed as linear time-invariant systems. A real data set of a PBPK model for exposure to dimethyl arsinic acid (DMA(V)) is presented to illustrate the proposed methodology.

  18. A NOVEL PNYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODEL FOR DIMETHYLARSINIC ACID (DMA): THE LUNG AS A STORAGE COMPARTMENT

    EPA Science Inventory

    A NOVEL PHYSIOLOGICALLY-BASED PHARMACOKINETIC (PBPK) MODEL FOR DIMETHYLARSINIC ACID (DMA): THE LUNG AS A STORAGE COMPARTMENT. Evans, M.V., Hughes, M.F., and Kenyon, E.M. USEPA, ORD, NHEERL, RTP, NC 27711

    DMA is the major methylated metabolite of inorganic arsenic, a kno...

  19. A NOVEL PNYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODEL FOR DIMETHYLARSINIC ACID (DMA): THE LUNG AS A STORAGE COMPARTMENT

    EPA Science Inventory

    A NOVEL PHYSIOLOGICALLY-BASED PHARMACOKINETIC (PBPK) MODEL FOR DIMETHYLARSINIC ACID (DMA): THE LUNG AS A STORAGE COMPARTMENT. Evans, M.V., Hughes, M.F., and Kenyon, E.M. USEPA, ORD, NHEERL, RTP, NC 27711

    DMA is the major methylated metabolite of inorganic arsenic, a kno...

  20. Tissue Distribution and Urinary Excretion of Dimethylated Arsenic and Its Metabolites in Dimethylarsinic acid- or Arsenate-treated Rats - MCEARD

    EPA Science Inventory

    Adult female Fisher 344 rats received drinking water containing 0, 4, 40, 100, or 200 parts per million of dimethylarsinic acid or 100 parts per million of arsenate for 14 days. Urine was collected during the last 24 h of exposure. Tissues were then taken for analysis of dimethy...

  1. Tissue Distribution and Urinary Excretion of Dimethylated Arsenic and Its Metabolites in Dimethylarsinic acid- or Arsenate-treated Rats - MCEARD

    EPA Science Inventory

    Adult female Fisher 344 rats received drinking water containing 0, 4, 40, 100, or 200 parts per million of dimethylarsinic acid or 100 parts per million of arsenate for 14 days. Urine was collected during the last 24 h of exposure. Tissues were then taken for analysis of dimethy...

  2. [Effects of exogenous dimethylarsinic acid on Brassica campestris growth and soil arsenic bioavailability].

    PubMed

    Bai, Ling-Yu; Zeng, Xi-Bai; Hu, Liu-Jie; Li, Lian-Fang; He, Qiu-Hong

    2011-02-01

    A pot experiment was conducted to study the effects of exogenous dimethylarsinic acid (DMA) on the growth of Brassica campestris and the bioavailability of soil arsenic (As). With the increasing concentration of applied DMA, the emergence rate and biomass of B. campestris increased at low concentration DMA, but decreased at high concentration DMA. When the DMA concentration reached 90 mg x kg(-1), the emergence rate and biomass of B. campestris in the second cropping decreased by 9.5% and 57.0%, respectively, compared with those in the control, indicating that exogenous DMA had longer-term effects on the growth of B. campestris. The soil available As and the As uptake by B. campestris all increased with increasing concentration of exogenous DMA, and there existed significant correlations among them. After applied into soil, the exogenous DMA demethylated, with As(V) as the main product and lesser amount of As (III), and the concentrations of soil As(V) and As(III) increased with increasing application rate of exogenous DMA.

  3. Influence of aggregated particles on biodegradation activities for dimethylarsinic acid (DMA) in Lake Kahokugata.

    PubMed

    Maki, Teruya; Hirota, Wakana; Motojima, Hiroyuki; Hasegawa, Hiroshi; Rahman, Mohammad Azizur

    2011-06-01

    Aquatic arsenic cycles mainly depend on microbial activities that change the arsenic chemical forms and influence human health and organism activities. The microbial aggregates degrading organic matter are significantly related to the turnover between inorganic arsenic and organoarsenic compounds. We investigated the effects of microbial aggregates on organoarsenic mineralization in Lake Kahokugata using lake water samples spiked with dimethylarsinic acid (DMA). The lake water samples converted 1 μmol L(-1) of DMA to inorganic arsenic for 28d only under anaerobic and dark conditions in the presence of microbial activities. During the DMA mineralization process, organic aggregates >5.0 μm with bacterial colonization increased the densities. When the organic aggregates >5.0 μm were eliminated from the lake water samples using filters, the degradation activities were reduced. DMA in the lake water would be mineralized by the microbial aggregates under anaerobic and dark conditions. Moreover, DMA amendment enhanced the degradation activities in the lake water samples, which mineralized 50 μmol L(-1) of DMA. The DMA-amended aggregates >5.0 μm completely degraded 1 μmol L(-1) of DMA with a shorter incubation time of 7d. The supplement of KNO(3) and NaHCO(3) to lake water samples also shortened the DMA-degradation period. Presumably, the bacterial aggregates involved in the chemical heterotrophic process would contribute to the DMA-biodegradation process in Lake Kahokugata, which is induced by the DMA amendment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Determination of arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid in cereals by hydride generation atomic fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Matos Reyes, M. N.; Cervera, M. L.; Campos, R. C.; de la Guardia, M.

    2007-09-01

    A fast, sensitive and simple non-chromatographic analytical method was developed for the speciation analysis of toxic arsenic species in cereal samples, namely rice and wheat semolina. An ultrasound-assisted extraction of the toxic arsenic species was performed with 1 mol L - 1 H 3PO 4 and 0.1% (m/v) Triton XT-114. After extraction, As(III), As(V), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) concentrations were determined by hydride generation atomic fluorescence spectrometry using a series of proportional equations corresponding to four different experimental reduction conditions. The detection limits of the method were 1.3, 0.9, 1.5 and 0.6 ng g - 1 for As(III), As(V), DMA and MMA, respectively, expressed in terms of sample dry weight. Recoveries were always greater than 90%, and no species interconversion occurred. The speciation analysis of a rice flour reference material certified for total arsenic led to coherent results, which were also in agreement with other speciation studies made on the same certified reference material.

  5. Dimethylarsinic acid in drinking water changed the morphology but not the expression of DNA repair genes of bladder transitional epithelium in F344 rats

    EPA Science Inventory

    Inorganic arsenic increases urinary bladder transitional cell carcinoma in humans. In laboratory animals, it is dimethylarsinic acid [DMA(V)], a major arsenic metabolite in the urine of inorganic arsenic-exposed people, that increases transitional cell carcinoma, namely in F344 r...

  6. Dimethylarsinic acid in drinking water changed the morphology but not the expression of DNA repair genes of bladder transitional epithelium in F344 rats

    EPA Science Inventory

    Inorganic arsenic increases urinary bladder transitional cell carcinoma in humans. In laboratory animals, it is dimethylarsinic acid [DMA(V)], a major arsenic metabolite in the urine of inorganic arsenic-exposed people, that increases transitional cell carcinoma, namely in F344 r...

  7. Biokinetics and subchronic toxic effects of oral arsenite, arsenate, monomethylarsonic acid, and dimethylarsinic acid in v-Ha-ras transgenic (Tg.AC) mice.

    PubMed

    Xie, Yaxiong; Trouba, Kevin J; Liu, Jie; Waalkes, Michael P; Germolec, Dori R

    2004-08-01

    Previous research demonstrated that 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment increased the number of skin papillomas in v-Ha-ras transgenic (Tg.AC) mice that had received sodium arsenite [(As(III)] in drinking water, indicating that this model is useful for studying the toxic effects of arsenic in vivo. Because the liver is a known target of arsenic, we examined the pathophysiologic and molecular effects of inorganic and organic arsenical exposure on Tg.AC mouse liver in this study. Tg.AC mice were provided drinking water containing As(III), sodium arsenate [As(V)], monomethylarsonic acid [(MMA(V)], and 1,000 ppm dimethylarsinic acid [DMA(V)] at dosages of 150, 200, 1,500, or 1,000 ppm as arsenic, respectively, for 17 weeks. Control mice received unaltered water. Four weeks after initiation of arsenic treatment, TPA at a dose of 1.25 microg/200 microL acetone was applied twice a week for 2 weeks to the shaved dorsal skin of all mice, including the controls not receiving arsenic. In some cases arsenic exposure reduced body weight gain and caused mortality (including moribundity). Arsenical exposure resulted in a dose-dependent accumulation of arsenic in the liver that was unexpectedly independent of chemical species and produced hepatic global DNA hypomethylation. cDNA microarray and reverse transcriptase-polymerase chain reaction analysis revealed that all arsenicals altered the expression of numerous genes associated with toxicity and cancer. However, organic arsenicals [MMA(V) and DMA(V)] induced a pattern of gene expression dissimilar to that of inorganic arsenicals. In summary, subchronic exposure of Tg.AC mice to inorganic or organic arsenicals resulted in toxic manifestations, hepatic arsenic accumulation, global DNA hypomethylation, and numerous gene expression changes. These effects may play a role in arsenic-induced hepatotoxicity and carcinogenesis and may be of particular toxicologic relevance.

  8. Toxicological properties of the thiolated inorganic arsenic and arsenosugar metabolite thio-dimethylarsinic acid in human bladder cells.

    PubMed

    Ebert, Franziska; Leffers, Larissa; Weber, Till; Berndt, Svenia; Mangerich, Aswin; Beneke, Sascha; Bürkle, Alexander; Schwerdtle, Tanja

    2014-04-01

    Thio-dimethylarsinic acid (thio-DMA(V)) has recently been identified as human metabolite after exposure toward both the human carcinogen inorganic arsenic and arsenosugars, which are the major arsenical constituents of marine algae. This study aims to get further insight in the toxic modes of action of thio-DMA(V) in cultured human urothelial cells. Among others effects of thio-DMA(V) on eight cell death related endpoints, cell cycle distribution, genotoxicity, cellular bioavailability as well as for the first time its impact on DNA damage induced poly(ADP-ribosyl)ation were investigated and compared to effects induced by arsenite. The data indicate that thio-DMA(V) exerts its cellular toxicity in a similar or even lower concentration range, however most likely via different mechanisms, than arsenite. Most interestingly, thio-DMA(V) decreased damage-induced cellular poly(ADP-ribosyl)ation by 35,000-fold lower concentrations than arsenite. The inhibition of this essential DNA-damage induced and DNA-repair related signaling reaction might contribute to inorganic arsenic induced toxicity, at least in the bladder. Therefore, and also because thio-DMA(V) is to date by far the most toxic human metabolite identified after arsenosugar intake, thio-DMA(V) should contemporary be fully (also in vivo) toxicologically characterized, to assess risks to human health related to inorganic arsenic but especially arsenosugar dietary intake.

  9. Renal, hepatic, pulmonary and adrenal tumors induced by prenatal inorganic arsenic followed by dimethylarsinic acid in adulthood in CD1 mice

    PubMed Central

    Tokar, Erik J.; Diwan, Bhalchandra A.; Waalkes, Michael P.

    2012-01-01

    Inorganic arsenic, an early life carcinogen in humans and mice, can initiate lesions promotable by other agents in later life. The biomethylation product of arsenic, dimethylarsinic acid (DMA), is a multi-site tumor promoter. Thus, pregnant CD1 mice were given drinking water (0 or 85 ppm arsenic) from gestation day 8 to 18 and after weaning male offspring received DMA (0 or 200 ppm; drinking water) for up to 2 years. No renal tumors occurred in controls or DMA alone treated mice while gestational arsenic exposure plus later DMA induced a significant renal tumor incidence of 17% (primarily renal cell carcinoma). Arsenic plus DMA or arsenic alone also increased renal hyperplasia over control but DMA alone did not. Arsenic alone, DMA alone and arsenic plus DMA all induced urinary bladder hyperplasia (33–35%) versus control (2%). Compared to control (6%), arsenic alone tripled hepatocellular carcinoma (20%), and arsenic plus DMA doubled this rate again (43%), but DMA alone had no effect. DMA alone, arsenic alone, and arsenic plus DMA increased lung adenocarcinomas and adrenal adenomas versus control. Overall, DMA in adulthood promoted tumors/lesions initiated by prenatal arsenic in the kidney and liver, but acted independently in the urinary bladder, lung and adrenal. PMID:22230260

  10. The endoplasmic reticulum is a target organelle for trivalent dimethylarsinic acid (DMA{sup III})-induced cytotoxicity

    SciTech Connect

    Naranmandura, Hua; Xu, Shi; Koike, Shota; Pan, Li Qiang; Chen, Bin; Wang, Yan Wei; Rehman, Kanwal; Wu, Bin; Chen, Zhe; Suzuki, Noriyuki

    2012-05-01

    The purpose of present study was to characterize the endoplasmic reticulum stress and generation of ROS in rat liver RLC-16 cells by exposing to trivalent dimethylarsinous acid (DMA{sup III}) and compared with that of trivalent arsenite (iAs{sup III}) and monomethylarsonous acid (MMA{sup III}). Protein kinase-like endoplasmic reticulum kinase (PERK) phosphorylation was significantly induced in cells exposed to DMA{sup III}, while there was no change in phosphorylated PERK (P-PERK) detected in cells after exposure to iAs{sup III} or MMA{sup III}. The generation of reactive oxygen species (ROS) after DMA{sup III} exposure was found to take place specifically in the endoplasmic reticulum (ER), while previous reports showed that ROS was generated in mitochondria following exposure to MMA{sup III}. Meanwhile, cycloheximide (CHX) which is an inhibitor of protein biosynthesis strongly inhibited the DMA{sup III}-induced intracellular ROS generation in the ER and the phosphorylation of PERK, suggesting the induction of ER stress probably occurs through the inhibition of the protein folding process. Activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP) mRNA were induced by all three arsenic species, however, evidence suggested that they might be induced by different pathways in the case of iAs{sup III} and MMA{sup III}. In addition, ER resident molecular chaperone glucose-regulated protein78 (GRP78) was not affected by trivalent arsenicals, while it was induced in positive control only at high concentration (Thapsigargin;Tg), suggesting the GRP78 is less sensitive to low levels of ER stress. In summary, our findings demonstrate that the endoplasmic reticulum is a target organelle for DMA{sup III}-induced cytotoxicity. Highlights: ►ER is a target organelle for trivalent DMA{sup III}-induced cytotoxicity. ►Generation of ROS in ER can be induced specially by trivalent DMA{sup III}. ►ER-stress and generation of ROS are caused by the increase in

  11. The mechanisms of detoxification of As(III), dimethylarsinic acid (DMA) and As(V) in the microalga Chlorella vulgaris.

    PubMed

    Pantoja Munoz, L; Purchase, D; Jones, H; Raab, A; Urgast, D; Feldmann, J; Garelick, H

    2016-06-01

    The response of Chlorella vulgaris when challenged by As(III), As(V) and dimethylarsinic acid (DMA) was assessed through experiments on adsorption, efflux and speciation of arsenic (reduction, oxidation, methylation and chelation with glutathione/phytochelatin [GSH/PC]). Our study indicates that at high concentrations of phosphate (1.62mM of HPO4(2-)), upon exposure to As(V), cells are able to shift towards methylation of As(V) rather than PC formation. Treatment with As(V) caused a moderate decrease in intracellular pH and a strong increase in the concentration of free thiols (GSH). Passive surface adsorption was found to be negligible for living cells exposed to DMA and As(V). However, adsorption of As(III) was observed to be an active process in C. vulgaris, because it did not show saturation at any of the exposure periods. Chelation of As(III) with GS/PC and to a lesser extent hGS/hPC is a major detoxification mechanism employed by C. vulgaris cells when exposed to As(III). The increase of bound As-GS/PC complexes was found to be strongly related to an increase in concentration of As(III) in media. C. vulgaris cells did not produce any As-GS/PC complex when exposed to As(V). This may indicate that a reduction step is needed for As(V) complexation with GSH/PC. C. vulgaris cells formed DMAS(V)-GS upon exposure to DMA independent of the exposure period. As(III) triggers the formation of arsenic complexes with PC and homophytochelatins (hPC) and their compartmentalisation to vacuoles. A conceptual model was devised to explain the mechanisms involving ABCC1/2 transport. The potential of C. vulgaris to bio-remediate arsenic from water appeared to be highly selective and effective without the potential hazard of reducing As(V) to As(III), which is more toxic to humans. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. In situ ATR-FTIR and surface complexation modeling studies on the adsorption of dimethylarsinic acid and p-arsanilic acid on iron-(oxyhydr)oxides.

    PubMed

    Mitchell, William; Goldberg, Sabine; Al-Abadleh, Hind A

    2011-06-15

    Arsenic is an element that exists naturally in many rocks and minerals around the world. It also accumulates in petroleum, shale, oil sands, and coal deposits as a result of biogeochemical processes, and it has been found in fly ash from the combustion of solid biofuels. Arsenic compounds in their organic and inorganic forms pose both a health and an environmental risk, and continue to be a challenge to the energy industry. The environmental fate and removal technologies of arsenic compounds are controlled to a large extent by their surface interactions with inorganic and organic adsorbents. We report thermodynamic binding constants, K(binding), from applying the triple-layer surface complexation model to adsorption isotherm and pH envelope data for dimethylarsinic acid (DMA) and p-arsanilic acid (p-AsA) on hematite and goethite. Ligand exchange reactions were constructed based on the interpretation of ATR-FTIR spectra of DMA and p-AsA surface complexes. Surface coverage of adsorbates was quantified in situ from the spectral component at 840 cm(-1). The best fit to the DMA adsorption data was obtained using outer-sphere complex formation, whereas for p-AsA, the best fit was obtained using two monodentate inner-sphere surface complexes. The significance of the results is discussed in relation to improving modeling tools used by environmental regulators and the energy sector for optimum control of arsenic content in fuels.

  13. GENE EXPRESSION CAN DIFFERENTIATE CARCINOGENIC FROM NON-CARCINOGENIC DOSES OF DIMETHYLARSINIC ACID (DMAv) IN THE TRANSITIONAL EPITHELIUM OF THE URINARY BLADDER FROM FEMALE F344 RATS

    EPA Science Inventory

    Arsenic is an environmental concern worldwide, and drinking arsenic contaminated water has been associated with increased incidences of skin, lung and bladder cancer. Dimethylarsinic acid (DMAv) is a major metabolite of inorganic arsenic in rodents and humans and is the predomina...

  14. GENE EXPRESSION CAN DIFFERENTIATE CARCINOGENIC FROM NON-CARCINOGENIC DOSES OF DIMETHYLARSINIC ACID (DMAv) IN THE TRANSITIONAL EPITHELIUM OF THE URINARY BLADDER FROM FEMALE F344 RATS

    EPA Science Inventory

    Arsenic is an environmental concern worldwide, and drinking arsenic contaminated water has been associated with increased incidences of skin, lung and bladder cancer. Dimethylarsinic acid (DMAv) is a major metabolite of inorganic arsenic in rodents and humans and is the predomina...

  15. DIMETHYLARSINIC ACID ALTERS EXPRESSION OF OXIDATIVE STRESS AND DNA REPAIR GENES IN A DOSE DEPENDENT MANNER IN THE TRANSITIONAL EPITHELIUM OF THE URINARY BLADDER FROM FEMALE F344 RATS.

    EPA Science Inventory

    Dose-dependent alteration of oxidative stress and DNA repair gene expression by Dimethylarsinic acid [DMA(V)] in transitional epithelium of urinary bladder from female F344 rats.
    Arsenic (As) is a major concern as millions of people are at risk from drinking arsenic contaminat...

  16. DIMETHYLARSINIC ACID ALTERS EXPRESSION OF OXIDATIVE STRESS AND DNA REPAIR GENES IN A DOSE DEPENDENT MANNER IN THE TRANSITIONAL EPITHELIUM OF THE URINARY BLADDER FROM FEMALE F344 RATS.

    EPA Science Inventory

    Dose-dependent alteration of oxidative stress and DNA repair gene expression by Dimethylarsinic acid [DMA(V)] in transitional epithelium of urinary bladder from female F344 rats.
    Arsenic (As) is a major concern as millions of people are at risk from drinking arsenic contaminat...

  17. Dimethylarsinic acid in drinking water changed the morphology of urinary bladder but not the expression of DNA repair genes of bladder transitional epithelium in F344 rats.

    PubMed

    Wang, Amy; Wolf, Douglas C; Sen, Banalata; Knapp, Geremy W; Holladay, Steven D; Huckle, William R; Caceci, Thomas; Robertson, John L

    2009-06-01

    Inorganic arsenic increases urinary bladder transitional cell carcinoma in humans. In F344 rats, dimethylarsinic acid (DMA[V]) increases transitional cell carcinoma. Arsenic-induced inhibition of DNA repair has been reported in cultured cell lines and in lymphocytes of arsenic-exposed humans, but it has not been studied in urinary bladder. Should inhibition of DNA damage repair in transitional epithelium occur, it may contribute to carcinogenesis or cocarcinogenesis. We investigated morphology and expression of DNA repair genes in F344 rat transitional cells following up to 100 ppm DMA(V) in drinking water for four weeks. Mitochondria were very sensitive to DMA(V), and swollen mitochondria appeared to be the main source of vacuoles in the transitional epithelium. Real-time reverse transcriptase polymerase chain reaction (Real-Time RT PCR) showed the mRNA levels of tested DNA repair genes, ataxia telangectasia mutant (ATM), X-ray repair cross-complementing group 1 (XRCC1), excision repair cross-complementing group 3/xeroderma pigmentosum B (ERCC3/XPB), and DNA polymerase beta (Polbeta), were not altered by DMA(V). These data suggested that either DMA(V) does not affect DNA repair in the bladder or DMA(V) affects DNA repair without affecting baseline mRNA levels of repair genes. The possibility remains that DMA(V) may lower damage-induced increases in repair gene expression or cause post-translational modification of repair enzymes.

  18. A novel approach for the analysis of dimethylarsinic acid in various liquid samples by WDXRF combined to pre-concentration with solid phase extraction disk

    NASA Astrophysics Data System (ADS)

    An, J.; Kim, J.; Kong, M.; Kim, K.; Yoon, H.

    2012-12-01

    Once dimethylarsinic acid (DMA) was considered to a product of detoxification (biomethylation) of inorganic arsenicals in organisms, it is now thought to have severe health risk. Since DMA had been widely employed in industrial and agricultural fields (e.g., pesticides and herbicides), it was one of the most often determined species in the published literatures for last decades. In the present study, DMA was pre-concentrated from various liquid samples with strong cation exchange (SCX) disk functionalized with sulfonic groups, and then analyzed by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). While arsenate (iAsV), arsenite (iAsIII), and monomethylarsonic acid (MMA) were not retained on the SCX disk at all, DMA was perfectly adsorbed onto the surface of SCX disk. We optimized analytical conditions of SCX-WDXRF system and its calibration curve exhibited a strong linearity (R2 = 0.9996). Limit of detection (LOD) was achieved to 0.254 μg/L if a 1 L of liquid sample was used. We aimed to achieve improved instrumental sensitivity and the LOD for the analysis of DMA in liquid samples compared to high performance liquid chromatography linked to inductively coupled plasma mass spectrometry (HPLC-ICPMS) conventionally used in arsenic speciation researches. Spike tests for iAsV, iAsIII, MMA, and DMA in three types of liquid samples (i.e., deionized water, synthetic seawater and landfill leachate) showed quantitative recoveries (i.e., 95-105%) when the line overlap between As-Kα and Pb-Lα was corrected. This system highlights a very good option in arsenic speciation fields due to its extreme simplicity of operation and low cost.

  19. A novel pathway for arsenic elimination: human multidrug resistance protein 4 (MRP4/ABCC4) mediates cellular export of dimethylarsinic acid (DMAV) and the diglutathione conjugate of monomethylarsonous acid (MMAIII).

    PubMed

    Banerjee, Mayukh; Carew, Michael W; Roggenbeck, Barbara A; Whitlock, Brayden D; Naranmandura, Hua; Le, X Chris; Leslie, Elaine M

    2014-08-01

    Hundreds of millions of people worldwide are exposed to unacceptable levels of arsenic in drinking water. This is a public health crisis because arsenic is a Group I (proven) human carcinogen. Human cells methylate arsenic to monomethylarsonous acid (MMA(III)), monomethylarsonic acid (MMA(V)), dimethylarsinous acid (DMA(III)), and dimethylarsinic acid (DMA(V)). Although the liver is the predominant site for arsenic methylation, elimination occurs mostly in urine. The protein(s) responsible for transport of arsenic from the liver (into blood), ultimately for urinary elimination, are unknown. Human multidrug resistance protein 1 (MRP1/ABCC1) and MRP2 (ABCC2) are established arsenic efflux pumps, but unlike the related MRP4 (ABCC4) are not present at the basolateral membrane of hepatocytes. MRP4 is also found at the apical membrane of renal proximal tubule cells, making it an ideal candidate for urinary arsenic elimination. In the current study, human MRP4 expressed in HEK293 cells reduced the cytotoxicity and cellular accumulation of arsenate, MMA(III), MMA(V), DMA(III), and DMA(V) while two other hepatic basolateral MRPs (MRP3 and MRP5) did not. Transport studies with MRP4-enriched membrane vesicles revealed that the diglutathione conjugate of MMA(III), monomethylarsenic diglutathione [MMA(GS)(2)], and DMA(V) were the transported species. MMA(GS)(2) and DMA(V) transport was osmotically sensitive, allosteric (Hill coefficients of 1.4 ± 0.2 and 2.9 ± 1.2, respectively), and high affinity (K0.5 of 0.70 ± 0.16 and 0.22 ± 0.15 μM, respectively). DMA(V) transport was pH-dependent, with highest affinity and capacity at pH 5.5. These results suggest that human MRP4 could be a major player in the elimination of arsenic. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  20. Reduction of the Pentavalent Arsenical Dimethylarsinic Acid and the GSTO1 Substrate S-(4-Nitrophenacyl)glutathione by Rat Liver Cytosol: Analyzing the Role of GSTO1 in Arsenic Reduction.

    PubMed

    Németi, Balázs; Poór, Miklós; Gregus, Zoltán

    2015-11-16

    Dimethylarsinic acid (DMAs(V)) is the major urinary metabolite of inorganic arsenic. The relatively atoxic DMAs(V) is reduced in the body to the much more toxic and thiol-reactive dimethylarsinous acid (DMAs(III)). Glutathione S-transferase omega 1 (GSTO1) can catalyze this toxification step; however, its role in the reduction of DMAs(V) in vivo or by tissue extracts is unclear. Therefore, we assessed the role of GSTO1 in the reduction of DMAs(V) to DMAs(III) by rat liver cytosol. The experiments revealed that glutathione (GSH) supported the cytosolic DMAs(V) reduction specifically and that GSH analogues and GSH conjugates, such as S-alkylglutathiones and S-(4-nitrophenacyl)glutathione (4-NPG; a GSTO1 specific substrate), inhibited the formation of DMAs(III). Observations in line with the view that GSTO1 catalyzes the cytosolic reduction of DMAs(V) include (i) findings pointing to the presence of a GSH-binding site on the DMAs(V)-reducing cytosolic enzyme, (ii) identical responsiveness of the DMAs(V)- and 4-NPG-reducing activities in rat liver cytosol to the GSTO1 specific inhibitors KT53 and chloromethylfluorescein diacetate, and (iii) perfect coelution of the two activities during affinity and anion exchange chromatography of cytosolic proteins. Other observations appear ambiguous as to the role of GSTO1 in the cytosolic reduction of DMAs(V). These include the different sensitivities of the DMAs(V)-reducing and GSTO1 activities to aurothioglucose, trivalent antimony, and zinc ions, as well as the preserved GSTO1 activity in cytosols whose DMAs(V)-reducing activity was lost due to spontaneous thiol oxidation. These disparate findings may be reconciled by assuming that GSTO1 catalyzes the reduction of both DMAs(V) and 4-NPG in rat liver cytosol; however, the enzyme employs different sites and/or mechanisms when reducing these substrates.

  1. DIMETHYLARSINE AND TRIMETHYLARSINE ARE POTENT GENOTOXINS IN VITRO.

    EPA Science Inventory

    Dimethylarsine and Trimethylarsine are potent genotoxins in vitro
    Andrewes, P; Kitchin, KT; and Wallace, KA

    Abstract
    The mechanism of arsenic carcinogenesis is unclear. A complicating factor receiving increasing attention is that arsenic is biomethylated to form vari...

  2. Identifiability of PBPK Models with Applications to Dimethylarsinic Acid Exposure

    EPA Science Inventory

    Any statistical model should be identifiable in order for estimates and tests using it to be meaningful. We consider statistical analysis of physiologically-based pharmacokinetic (PBPK) models in which parameters cannot be estimated precisely from available data, and discuss diff...

  3. Identifiability of PBPK Models with Applications to Dimethylarsinic Acid Exposure

    EPA Science Inventory

    Any statistical model should be identifiable in order for estimates and tests using it to be meaningful. We consider statistical analysis of physiologically-based pharmacokinetic (PBPK) models in which parameters cannot be estimated precisely from available data, and discuss diff...

  4. Initiating meiosis: the case for retinoic acid.

    PubMed

    Griswold, Michael D; Hogarth, Cathryn A; Bowles, Josephine; Koopman, Peter

    2012-02-01

    The requirement for vitamin A in reproduction and development was first determined from studies of nutritional deficiencies. Subsequent research has shown that embryonic development and both male and female reproduction are modulated by retinoic acid (RA), the active form of vitamin A. Because RA is active in multiple developmental systems, its synthesis, transport, and degradation are tightly regulated in different tissues. A growing body of evidence implicates RA as a requirement for the initiation of meiosis in both male and female mammals, resulting in a mechanistic model involving the interplay of RA, RA synthesis enzymes, RA receptors, and degradative cytochrome P450 enzymes in this system. Recently, that model has been challenged, prompting a review of the established paradigm. While it remains possible that additional molecules may be involved in regulating entry into meiosis, the weight of evidence supporting a key role for RA is incontrovertible.

  5. PLASMID DNA DAMAGE CAUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    EPA Science Inventory

    PLASMID DNA DAMAGE CAOUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    ABSTRACT

    Both dimethylarsinic acid (DMA(V)) and dimethylarsinous acid (DMA(III)) release iron from human liver ferritin (HLF) with or without the presence of ascorbic acid. ...

  6. PLASMID DNA DAMAGE CAUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    EPA Science Inventory

    PLASMID DNA DAMAGE CAOUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    ABSTRACT

    Both dimethylarsinic acid (DMA(V)) and dimethylarsinous acid (DMA(III)) release iron from human liver ferritin (HLF) with or without the presence of ascorbic acid. ...

  7. Toxicity of a trivalent organic arsenic compound, dimethylarsinous glutathione in a rat liver cell line (TRL 1215).

    PubMed

    Sakurai, T; Kojima, C; Kobayashi, Y; Hirano, S; Sakurai, M H; Waalkes, M P; Himeno, S

    2006-12-01

    Although inorganic arsenite (As(III)) is toxic in humans, it has recently emerged as an effective chemotherapeutic agent for acute promyelocytic leukemia (APL). In humans and most animals, As(III) is enzymatically methylated in the liver to weakly toxic dimethylarsinic acid (DMAs(V)) that is a major pentavalent methylarsenic metabolite. Recent reports have indicated that trivalent methylarsenicals are produced through methylation of As(III) and participate in arsenic poisoning. Trivalent methylarsenicals may be generated as arsenical-glutathione conjugates, such as dimethylarsinous glutathione (DMAs(III)G), during the methylation process. However, less information is available on the cytotoxicity of DMAs(III)G. We synthesized and purified DMAs(III)G using high performance TLC (HPTLC) methods and measured its cytotoxicity in rat liver cell line (TRL 1215 cells). DMAs(III)G was highly cytotoxic in TRL 1215 cells with a LC(50) of 160 nM. We also found that DMAs(III)G molecule itself was not transported efficiently into the cells and was not cytotoxic; however it readily became strongly cytotoxic by dissociating into trivalent dimethylarsenicals and glutathione (GSH). The addition of GSH in micromolar physiological concentrations prevented the breakdown of DMAs(III)G, and the DMAs(III)G-induced cytotoxicity. Physiological concentrations of normal human serum (HS), human serum albumin (HSA), and human red blood cells (HRBC) also reduced both the cytotoxicity and cellular arsenic uptake induced by exposure to DMAs(III)G. These findings suggest that the significant cytotoxicity induced by DMAs(III)G may not be seen in healthy humans, even if DMAs(III)G is formed in the body from As(III).

  8. Toxicity of a trivalent organic arsenic compound, dimethylarsinous glutathione in a rat liver cell line (TRL 1215)

    PubMed Central

    Sakurai, T; Kojima, C; Kobayashi, Y; Hirano, S; Sakurai, M H; Waalkes, M P; Himeno, S

    2006-01-01

    Background and purpose: Although inorganic arsenite (AsIII) is toxic in humans, it has recently emerged as an effective chemotherapeutic agent for acute promyelocytic leukemia (APL). In humans and most animals, AsIII is enzymatically methylated in the liver to weakly toxic dimethylarsinic acid (DMAsV) that is a major pentavalent methylarsenic metabolite. Recent reports have indicated that trivalent methylarsenicals are produced through methylation of AsIII and participate in arsenic poisoning. Trivalent methylarsenicals may be generated as arsenical–glutathione conjugates, such as dimethylarsinous glutathione (DMAsIIIG), during the methylation process. However, less information is available on the cytotoxicity of DMAsIIIG. Experimental approach: We synthesized and purified DMAsIIIG using high performance TLC (HPTLC) methods and measured its cytotoxicity in rat liver cell line (TRL 1215 cells). Key results: DMAsIIIG was highly cytotoxic in TRL 1215 cells with a LC50 of 160 nM. We also found that DMAsIIIG molecule itself was not transported efficiently into the cells and was not cytotoxic; however it readily became strongly cytotoxic by dissociating into trivalent dimethylarsenicals and glutathione (GSH). The addition of GSH in micromolar physiological concentrations prevented the breakdown of DMAsIIIG, and the DMAsIIIG-induced cytotoxicity. Physiological concentrations of normal human serum (HS), human serum albumin (HSA), and human red blood cells (HRBC) also reduced both the cytotoxicity and cellular arsenic uptake induced by exposure to DMAsIIIG. Conclusions and implications: These findings suggest that the significant cytotoxicity induced by DMAsIIIG may not be seen in healthy humans, even if DMAsIIIG is formed in the body from AsIII. PMID:17043674

  9. Contemporary issues surrounding folic Acid fortification initiatives.

    PubMed

    Choi, Jeong-Hwa; Yates, Zoe; Veysey, Martin; Heo, Young-Ran; Lucock, Mark

    2014-12-01

    The impact of folate on health and disease, particularly pregnancy complications and congenital malformations, has been extensively studied. Mandatory folic acid fortification therefore has been implemented in multiple countries, resulting in a reduction in the occurrence of neural tube defects. However, emerging evidence suggests increased folate intake may also be associated with unexpected adverse effects. This literature review focuses on contemporary issues of concern, and possible underlying mechanisms as well as giving consideration the future direction of mandatory folic acid fortification. Folate fortification has been associated with the presence of unmetabolized folic acid (PteGlu) in blood, masking of vitamin B12 deficiency, increased dosage for anti-cancer medication, photo-catalysis of PteGlu leading to potential genotoxicity, and a role in the pathoaetiology of colorectal cancer. Increased folate intake has also been associated with twin birth and insulin resistance in offspring, and altered epigenetic mechanisms of inheritance. Although limited data exists to elucidate potential mechanisms underlying these issues, elevated blood folate level due to the excess use of PteGlu without consideration of an individual's specific phenotypic traits (e.g. genetic background and undiagnosed disease) may be relevant. Additionally, the accumulation of unmetabolized PteGlu may lead to inhibition of dihydrofolate reductase and other enzymes. Concerns notwithstanding, folic acid fortification has achieved enormous advances in public health. It therefore seems prudent to target and carefully monitor high risk groups, and to conduct well focused further research to better understand and to minimize any risk of mandatory folic acid fortification.

  10. Contemporary Issues Surrounding Folic Acid Fortification Initiatives

    PubMed Central

    Choi, Jeong-Hwa; Yates, Zoe; Veysey, Martin; Heo, Young-Ran; Lucock, Mark

    2014-01-01

    The impact of folate on health and disease, particularly pregnancy complications and congenital malformations, has been extensively studied. Mandatory folic acid fortification therefore has been implemented in multiple countries, resulting in a reduction in the occurrence of neural tube defects. However, emerging evidence suggests increased folate intake may also be associated with unexpected adverse effects. This literature review focuses on contemporary issues of concern, and possible underlying mechanisms as well as giving consideration the future direction of mandatory folic acid fortification. Folate fortification has been associated with the presence of unmetabolized folic acid (PteGlu) in blood, masking of vitamin B12 deficiency, increased dosage for anti-cancer medication, photo-catalysis of PteGlu leading to potential genotoxicity, and a role in the pathoaetiology of colorectal cancer. Increased folate intake has also been associated with twin birth and insulin resistance in offspring, and altered epigenetic mechanisms of inheritance. Although limited data exists to elucidate potential mechanisms underlying these issues, elevated blood folate level due to the excess use of PteGlu without consideration of an individual’s specific phenotypic traits (e.g. genetic background and undiagnosed disease) may be relevant. Additionally, the accumulation of unmetabolized PteGlu may lead to inhibition of dihydrofolate reductase and other enzymes. Concerns notwithstanding, folic acid fortification has achieved enormous advances in public health. It therefore seems prudent to target and carefully monitor high risk groups, and to conduct well focused further research to better understand and to minimize any risk of mandatory folic acid fortification. PMID:25580388

  11. Acetobacter pasteurianus metabolic change induced by initial acetic acid to adapt to acetic acid fermentation conditions.

    PubMed

    Zheng, Yu; Zhang, Renkuan; Yin, Haisong; Bai, Xiaolei; Chang, Yangang; Xia, Menglei; Wang, Min

    2017-08-02

    Initial acetic acid can improve the ethanol oxidation rate of acetic acid bacteria for acetic acid fermentation. In this work, Acetobacter pasteurianus was cultured in ethanol-free medium, and energy production was found to increase by 150% through glucose consumption induced by initial acetic acid. However, oxidation of ethanol, instead of glucose, became the main energy production pathway when upon culturing ethanol containing medium. Proteome assay was used to analyze the metabolism change induced by initial acetic acid, which provided insight into carbon metabolic and energy regulation of A. pasteurianus to adapt to acetic acid fermentation conditions. Results were further confirmed by quantitative real-time PCR. In summary, decreased intracellular ATP as a result of initial acetic acid inhibition improved the energy metabolism to produce more energy and thus adapt to the acetic acid fermentation conditions. A. pasteurianus upregulated the expression of enzymes related to TCA and ethanol oxidation to improve the energy metabolism pathway upon the addition of initial acetic acid. However, enzymes involved in the pentose phosphate pathway, the main pathway of glucose metabolism, were downregulated to induce a change in carbon metabolism. Additionally, the enhancement of alcohol dehydrogenase expression promoted ethanol oxidation and strengthened the acetification rate, thereby producing a strong proton motive force that was necessary for energy production and cell tolerance to acetic acid.

  12. Respiratory failure as initial symptom of acid maltase deficiency.

    PubMed Central

    Keunen, R W; Lambregts, P C; Op de Coul, A A; Joosten, E M

    1984-01-01

    Nine patients with adult onset acid maltase deficiency were seen at the Nijmegen University Hospital and the St Elisabeth Hospital, Tilburg , during the period 1970-1982. Five of these patients developed respiratory failure, and in four this was the initial symptom. The occurrence of respiratory failure as an early symptom of this muscular disease is discussed. Images PMID:6429285

  13. Respiratory failure as initial symptom of acid maltase deficiency.

    PubMed

    Keunen, R W; Lambregts, P C; Op de Coul, A A; Joosten, E M

    1984-05-01

    Nine patients with adult onset acid maltase deficiency were seen at the Nijmegen University Hospital and the St Elisabeth Hospital, Tilburg , during the period 1970-1982. Five of these patients developed respiratory failure, and in four this was the initial symptom. The occurrence of respiratory failure as an early symptom of this muscular disease is discussed.

  14. The initial metabolic conversion of levulinic acid in Cupriavidus necator.

    PubMed

    Jaremko, Matt; Yu, Jian

    2011-09-20

    Levulinic acid or 4-ketovaleric acid is a potential renewable substrate for production of polyhydroxyalkanoates. In this work, the initial reactions of LA metabolism by Cupriavidus necator were examined in vitro. The organic acid was converted by membrane-bound crude enzymes obtained from the cells pre-grown on LA, while no LA activity was detected from cells pre-grown on acetic acid. Acetyl-CoA and propionyl-CoA were two major intermediates in the initial reactions of LA conversion. A mass balance on propionyl-CoA accounts for 84 mol% of LA added in vitro. It explains an interesting phenomenon that 3-hydroxbutyrate and 3-hydroxyvalerate are two major monomers of the biopolyester formed from LA, instead of 4-hydroxvalerate that has the similar chemical structure of LA as the precursor. A Monod model was used to describe the kinetics of LA utilization as a sole carbon source or a co-substrate of glucose and fructose. The μ(max) and K(m) of LA alone were 0.26 h⁻¹ and 0.01 g/L, respectively. The content and composition of PHA are also dependent on the culture conditions such as carbon to nitrogen ratio. The in vitro observation is supported by the high utilization rate of LA and the high molar percentage of 3HB and 3HV in the PHA derived from LA. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Identification of the major arsenic-binding protein in rat plasma as the ternary dimethylarsinous-hemoglobin-haptoglobin complex.

    PubMed

    Naranmandura, Hua; Suzuki, Kazuo T

    2008-03-01

    Chronic exposure to arsenic causes a wide range of diseases such as hyperkeratosis, cardiovascular diseases, and skin, lung, and bladder cancers, and millions of people are chronically exposed to arsenic worldwide. However, little is known about the mechanisms underlying these toxic actions. The metabolism of arsenic is essential for understanding the toxic actions. Here, we identified the major arsenic-binding protein (As-BP) in the plasma of rats after oral administration of arsenite by the use of two different HPLC columns, gel filtration and anion exchange ones, coupled with an inductively coupled argon plasma mass spectrometer (ICP MS). The molecular mass of the As-BP was estimated to be 90 kDa based on results using the former column, and arsenic bound to this protein only in the form of dimethylarsinous acid (DMA (III)) in the plasma in vivo. In addition, the purified As-BP was shown to consist of two different proteins, haptoglobin (Hp) of 37 kDa (three bands) and the hemoglobin (Hb) alpha chain of 14 kDa (single band), using sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS), respectively, suggesting that the As-BP was the ternary DMA (III)-Hb-Hp complex. To confirm the present observations, an arsenic-binding assay was carried out in vitro . Although DMA (III) bound directly to fresh rat plasma proteins, they were different from that identified in vivo. However, when a DMA (III)-exposed rat RBC lysate (DMA (III) binds to Hb in rat RBCs) was added to control rat plasma, a new arsenic peak increased at the expense of the arsenic-Hb one. Furthermore, this new arsenic peak was consistent with the As-BP identified in the plasma in vivo, suggesting that arsenic bound to Hb further binds to haptoglobin (Hp), forming the ternary As-Hb-Hp complex.

  16. Engineering Issue Paper: Biotransformation Pathways of Dimethylarsinic (Cacodylic) Acid in the Environment

    EPA Science Inventory

    This EIP summarizes the state of the science regarding the biotransformation of DMA(V) and was developed from peer-reviewed literature, scientific documents, EPA reports, internet sources, input from experts in the field, and other pertinent sources. This EIP includes a review o...

  17. GENE EXPRESSION PROFILING OF RESPONSES TO DIMETHYLARSINIC ACID IN FEMALE F344 RAT UROTHELIUM

    EPA Science Inventory

    Arsenic is a human carcinogen and epidemiologic evidence implicates it in the development of urinary bladder cancer. Even though several mechanisms have been proposed for arsenic carcinogenicity, the mode of action of inorganic arsenic (iAs) is confounded by the limited availabil...

  18. GENE EXPRESSION PROFILING OF RESPONSES TO DIMETHYLARSINIC ACID IN FEMALE F344 RAT UROTHELIUM

    EPA Science Inventory

    Arsenic is a human carcinogen and epidemiologic evidence implicates it in the development of urinary bladder cancer. Even though several mechanisms have been proposed for arsenic carcinogenicity, the mode of action of inorganic arsenic (iAs) is confounded by the limited availabil...

  19. Engineering Issue Paper: Biotransformation Pathways of Dimethylarsinic (Cacodylic) Acid in the Environment

    EPA Science Inventory

    This EIP summarizes the state of the science regarding the biotransformation of DMA(V) and was developed from peer-reviewed literature, scientific documents, EPA reports, internet sources, input from experts in the field, and other pertinent sources. This EIP includes a review o...

  20. Seafood Intake and Urine Concentrations of Total Arsenic, Dimethylarsinate and Arsenobetaine in the US Population

    PubMed Central

    Navas-Acien, Ana; Francesconi, Kevin A.; Silbergeld, Ellen K; Guallar, Eliseo

    2010-01-01

    Background Seafood is the main source of organic arsenic exposure (arsenobetaine, arsenosugars and arsenolipids) in the population. Arsenosugars and arsenolipids are metabolized to several species including dimethylarsinate (DMA). Objective Evaluate the association of seafood intake with spot urine arsenic concentrations in the 2003–2006 National Health Nutrition and Examination Survey (NHANES). Methods We studied 4276 participants ≥6 y. Total arsenic was measured using inductively coupled plasma dynamic reaction cell mass spectrometry (ICPMS). Urine DMA and arsenobetaine were measured by high-performance liquid chromatography coupled with ICPMS. Results Participants reporting seafood in the past 24-h had higher urine concentrations of total arsenic (median 24.5 vs. 7.3 µg/L), DMA (6.0 vs. 3.5 µg/L), arsenobetaine (10.2 vs. 0.9 µg/L) and total arsenic minus arsenobetaine (11.0 vs. 5.5 µg/L). Participants reporting seafood ≥2/wk vs. never during the past year had 2.3 (95% confidence interval 1.9, 2.7), 1.4 (1.2, 1.6), 6.0 (4.6, 7.8) and 1.7 (1.4, 2.0) times higher (p-trend <0.001) concentrations of total arsenic, DMA, arsenobetaine and total arsenic minus arsenobetaine, respectively. In participants without detectable arsenobetaine and in analyses adjusted for arsenobetaine, seafood consumption in the past year was not associated with total arsenic or DMA concentrations in urine. Conclusion Seafood intake was a major determinant of increased urine concentrations of total arsenic, DMA, arsenobetaine and total arsenic minus arsenobetaine in the US population. Epidemiologic studies that use total arsenic, DMA, the sum of inorganic arsenic, methylarsonate and DMA, and total arsenic minus arsenobetaine as markers of inorganic arsenic exposure and/or metabolism need to address seafood intake. PMID:21093857

  1. Ursolic acid mediates photosensitization by initiating mitochondrial-dependent apoptosis

    NASA Astrophysics Data System (ADS)

    Lee, Yuan-Hao; Wang, Exing; Kumar, Neeru; Glickman, Randolph D.

    2013-02-01

    The signaling pathways PI3K/Akt and MAPK play key roles in transcription, translation and carcinogenesis, and may be activated by light exposure. These pathways may be modulated or inhibited by naturally-occurring compounds, such as the triterpenoid, ursolic acid (UA). Previously, the transcription factors p53 and NF-kB, which transactivate mitochondrial apoptosis-related genes, were shown to be differentially modulated by UA. Our current work indicates that UA causes these effects via the mTOR and insulin-mediated pathways. UA-modulated apoptosis, following exposure to UV radiation, is observed to correspond to differential levels of oxidative stress in retinal pigment epithelial (RPE) and skin melanoma (SM) cells. Flow cytometry analysis, DHE (dihydroethidium) staining and membrane permeability assay showed that UA pretreatment potentiated cell cycle arrest and radiation-induced apoptosis selectively on SM cells while DNA photo-oxidative damage (i.e. strand breakage) was reduced, presumably by some antioxidant activity of UA in RPE cells. The UA-mediated NF-κB activation in SM cells was reduced by rapamycin pretreatment, which indicates that these agents exert inter-antagonistic effects in the PI3K/Akt/mTOR pathway. In contrast, the antagonistic effect of UA on the PI3K/Akt pathway was reversed by insulin leading to greater NF-κB and p53 activation in RPE cells. MitoTracker, a mitochondrial functional assay, indicated that mitochondria in RPE cells experienced reduced oxidative stress while those in SM cells exhibited increased oxidative stress upon UA pretreatment. When rapamycin administration was followed by UA, mitochondrial oxidative stress was increased in RPE cells but decreased in SM cells. These results indicate that UA modulates p53 and NF-κB, initiating a mitogenic response to radiation that triggers mitochondria-dependent apoptosis.

  2. Evaluation of the Initiation/Promotion Potential of CTFE Trimer Acid

    DTIC Science & Technology

    1990-11-01

    Chlorotrifluoroethylene Trimer Acid Hepatocarcinogenesis 43 Initiation Perhalogenated Fatty Acid 16. PRICE CODE Peroxisome Proliferator Promotion 17...peroxisomal proliferation. Several peroxisome proliferators have been shown to inhibit mitochondrial fatty acid oxidation in rat liver (Bone et al., 1982...in the fatty acid oxidase system (Harrison et al., 1988). These findings and the fact that mammals can oxidize n-alkanes to the corresponding fatty

  3. Humans seem to produce arsenobetaine and dimethylarsinate after a bolus dose of seafood.

    PubMed

    Molin, M; Ulven, S M; Dahl, L; Telle-Hansen, V H; Holck, M; Skjegstad, G; Ledsaak, O; Sloth, J J; Goessler, W; Oshaug, A; Alexander, J; Fliegel, D; Ydersbond, T A; Meltzer, H M

    2012-01-01

    Seafood is the predominant food source of several organoarsenic compounds. Some seafood species, like crustaceans and seaweed, also contain inorganic arsenic (iAs), a well-known toxicant. It is unclear whether human biotransformation of ingested organoarsenicals from seafood result in formation of arsenicals of health concern. The present controlled dietary study examined the urinary excretion of arsenic compounds (total arsenic (tAs), iAs, AB (arsenobetaine), dimethylarsinate (DMA) and methylarsonate (MA)) following ingestion of a single test meal of seafood (cod, 780 μg tAs, farmed salmon, 290 μg tAs or blue mussel, 690 μg tAs or potato (control, 110 μg tAs)) in 38 volunteers. The amount of ingested tAs excreted via the urine within 0-72 h varied significantly among the groups: Cod, 74% (52-92%), salmon 56% (46-82%), blue mussel 49% (37-78%), control 45% (30-60%). The estimated total urinary excretion of AB was higher than the amount of ingested AB in the blue mussel group (112%) and also ingestion of cod seemed to result in more AB, indicating possible endogenous formation of AB from other organoarsenicals. Excretion of iAs was lower than ingested (13-22% of the ingested iAs was excreted in the different groups). Although the ingested amount of iAs+DMA+MA was low for all seafood groups (1.2-4.5% of tAs ingested), the urinary DMA excretion was high in the blue mussel and salmon groups, counting for 25% and 11% of the excreted tAs respectively. In conclusion our data indicate a possible formation of AB as a result of biotransformation of other organic arsenicals. The considerable amount of DMA excreted is probably not only due to methylation of ingested iAs, but due to biotransformation of organoarsenicals making it an inappropriate biomarker of iAs exposure in populations with a high seafood intake. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Thio-dimethylarsinate is a common metabolite in urine samples from arsenic-exposed women in Bangladesh

    SciTech Connect

    Raml, Reingard; Rumpler, Alice; Goessler, Walter; Vahter, Marie; Li Li; Ochi, Takafumi; Francesconi, Kevin A.

    2007-08-01

    Over the last 6 years, much work on arsenic species in urine samples has been directed toward the determination of the reduced dimethylated arsenic species, DMA(III), because of its high toxicity and perceived key role in the metabolism of inorganic arsenic. Recent work, however, has suggested that DMA(III) may at times have been misidentified because its chromatographic properties can be similar to those of thio-dimethylarsinate (thio-DMA). We analyzed by HPLC-ICPMS (inductively coupled plasma mass spectrometry) urine samples from 75 arsenic-exposed women from Bangladesh with total arsenic concentrations ranging from 8 to 1034 {mu}g As/L and found that thio-DMA was present in 44% of the samples at concentrations ranging mostly from trace amounts to 24 {mu}g As/L (one sample contained 123 {mu}g As/L). Cytotoxicity testing with HepG2 cells derived from human hepatocarcinoma indicated that thio-DMA was about 10-fold more cytotoxic than dimethylarsinate (DMA). The widespread occurrence of thio-DMA in urine from these arsenic-exposed women suggests that this arsenical may also be present in other urine samples and has so far escaped detection. The work highlights the need for analytical methods providing specific determinations of arsenic compounds in future studies on arsenic metabolism and toxicology.

  5. Physiological responses to acid stress by Saccharomyces cerevisiae when applying high initial cell density

    PubMed Central

    Guo, Zhong-peng; Olsson, Lisbeth

    2016-01-01

    High initial cell density is used to increase volumetric productivity and shorten production time in lignocellulosic hydrolysate fermentation. Comparison of physiological parameters in high initial cell density cultivation of Saccharomyces cerevisiae in the presence of acetic, formic, levulinic and cinnamic acids demonstrated general and acid-specific responses of cells. All the acids studied impaired growth and inhibited glycolytic flux, and caused oxidative stress and accumulation of trehalose. However, trehalose may play a role other than protecting yeast cells from acid-induced oxidative stress. Unlike the other acids, cinnamic acid did not cause depletion of cellular ATP, but abolished the growth of yeast on ethanol. Compared with low initial cell density, increasing initial cell density reduced the lag phase and improved the bioconversion yield of cinnamic acid during acid adaptation. In addition, yeast cells were able to grow at elevated concentrations of acid, probable due to the increase in phenotypic cell-to-cell heterogeneity in large inoculum size. Furthermore, the specific growth rate and the specific rates of glucose consumption and metabolite production were significantly lower than at low initial cell density, which was a result of the accumulation of a large fraction of cells that persisted in a viable but non-proliferating state. PMID:27620460

  6. Physiological responses to acid stress by Saccharomyces cerevisiae when applying high initial cell density.

    PubMed

    Guo, Zhong-Peng; Olsson, Lisbeth

    2016-11-01

    High initial cell density is used to increase volumetric productivity and shorten production time in lignocellulosic hydrolysate fermentation. Comparison of physiological parameters in high initial cell density cultivation of Saccharomyces cerevisiae in the presence of acetic, formic, levulinic and cinnamic acids demonstrated general and acid-specific responses of cells. All the acids studied impaired growth and inhibited glycolytic flux, and caused oxidative stress and accumulation of trehalose. However, trehalose may play a role other than protecting yeast cells from acid-induced oxidative stress. Unlike the other acids, cinnamic acid did not cause depletion of cellular ATP, but abolished the growth of yeast on ethanol. Compared with low initial cell density, increasing initial cell density reduced the lag phase and improved the bioconversion yield of cinnamic acid during acid adaptation. In addition, yeast cells were able to grow at elevated concentrations of acid, probable due to the increase in phenotypic cell-to-cell heterogeneity in large inoculum size. Furthermore, the specific growth rate and the specific rates of glucose consumption and metabolite production were significantly lower than at low initial cell density, which was a result of the accumulation of a large fraction of cells that persisted in a viable but non-proliferating state. © FEMS 2016.

  7. Conversion of (Meth)acrylic acids to methane granular sludge: Initiation by specific anerobic microflora

    SciTech Connect

    Shtarkman, N.B.; Obraztova, A.Y.; Laurinavichyus, K.S.; Galushko, A.S.; Akimenko, V.K.

    1995-03-01

    The role of a specific anaerobic microflora in the initiation of degradation of (meth)acrylic acids to methane by granular sludge from a UASB reactor was investigated. Associations of anaerobic bacteria isolated from the anaerobic sludge, which was used for a long time for treatment of wastewater from (meth)acrylate production, were able to realize the initial stage of (meth)acrylic acid decomposition, i.e., a conversion of acrylic and methacrylic acids to propionic and isobutyric acids, respectively. When added to granules, these association played a role of an {open_quotes}initiator{close_quotes} of the degradation process, which was then continued by the granular sludge microflora utilizing propionate and isobutyrate. Some characteristics of the granules adapted to propionate or isobutyrate are presented. The rates of propionate and isobutyrate consumption by adapted granules is, respectively, 21 and 53 times higher than the values obtained for nonadapted granules. A combined use of {open_quotes}initiating{close_quotes} bacteria and adapted granules provided degradation of (meth)acrylic acids with a maximum methane yield. The possibility is discussed of employing the granules, which are adapted to short-chain fatty acids, and the {open_quotes}initiating{close_quotes} bacteria, which accomplish the initial steps of the organic material decomposition to lower fatty acids, for the conversion of various chemical compounds to methane. 10 refs., 3 figs., 2 tabs.

  8. Induction of Aneuploidy, Centrosome Abnormality, Multipolar Spindle, and Multipolar Division in Cultured Mammalian Cells Exposed to an Arsenic Metabolite, Dimethylarsinate.

    PubMed

    Ochi, Takafumi

    2016-01-01

    Toxicological studies of arsenic compounds were conducted in cultured mammalian cells to investigate the effects of glutathione (GSH) depletion. Dimethylarsinate DMA(V) was not cytotoxic in cells depleted of GSH, but was found to be cytotoxic when GSH was present outside the cells. The results suggested that a reactive form of DMA(V) was generated through interaction with GSH. Dimethylarsine iodide DMI(III) was used as a model compound of DMA(III), and the biological effects were investigated. DMI(III) was about 10000 times more toxic to the cells than DMA(V). Chromosome structural aberrations and numerical changes, such as aneuploidy, were induced by DMI(III). DMA(V) induced multiple foci of the centrosome protein, γ-tubulin, which were colocalized with multipolar spindles in mitotic cells. The multiple foci coalesced into a single dot on disruption of the microtubules (MT). However, reorganization of the MT caused multiple foci of γ-tubulin, suggesting that the induction of centrosome abnormalities by DMA(V) required intact MT. Inhibition of the MT-dependent motor, kinesin, prevented formation of multiple foci of γ-tubulin, which pointed to the involvement of the MT-dependent mitotic motor, kinesin, in the maintenance of centrosome abnormalities. DMI(III) caused abnormal cytokinesis (multipolar division). In addition, DMI(III) caused morphological transformation in Syrian hamster embryo cells. Consideration of the overall process following the centrosome abnormalities caused by DMA(V) suggested a mode of cytotoxicity in which the mitotic centrosome is a critical target.

  9. Processes and fluxes during the initial stage of acid sulfate soil formation

    NASA Astrophysics Data System (ADS)

    Gröger, J.; Hamer, K.; Schulz, H. D.

    2009-04-01

    Acid sulfate soils occur over a wide range of climatic zones, mainly in coastal landscapes. In these soils, the release of sulfuric acid by the oxidation of pyrite generates a very acidic environment (e.g., DENT and PONS, 1995, PONS, 1973). Two major types of acid sulfate soils can be distinguished: In actual acid sulfate soils, the initially contained pyrite was at least partly oxidized. This resulted in a severe acidification of the soil. Potential acid sulfate soils are generally unoxidized and contain large amounts of pyrite. Upon oxidation, these soils will turn into actual acid sulfate soils. By excavation or lowering of the groundwater table, potential acid sulfate soils can be exposed to atmospheric oxygen. During oxidation the pH drops sharply to values below pH 4. This acidification promotes the release of various metals, e.g., alumina, iron and heavy metals. Additionally, large quantities of sulfate are released. In order to assess the effects of disturbances of potential acid sulfate soils, for example by excavations during construction works, several large scale column experiments were conducted with various types of potential acid sulfate soils from Northern Germany. In these experiments, the oxidation and initial profile development of pyritic fen peats and thionic fluvisols were studied over a period of 14 months. The study focused on leaching and the translocation of various metals in the soil profile. To study mobilization processes, element fluxes and the progress of acidification, soil water and leachate were analyzed for total element concentrations. Furthermore, several redox-sensitive parameters, e.g., Fe2+ and sulfide, were measured and changes to the initial solid phase composition were analyzed. Chemical equilibria calculations of the soil water were used to gain insights into precipitation processes of secondary products of pyrite oxidation and leaching products. The results of this study will support the assessment of risks deriving from

  10. Disease progression in non-erosive reflux disease (NERD): impact of initial esophageal acid exposure.

    PubMed

    Chen, C L; Liu, T T; Yi, C H

    2010-11-01

    We investigated the 5-year clinical course in a cohort of patients with typical reflux symptoms and negative endoscopy. Prospective follow-up was conducted in patients with non-erosive reflux disease (NERD) for at least 5 years after initial evaluation with esophageal pH monitoring and upper gastrointestinal endoscopy. Within the last year of follow-up, reflux symptoms occurred in 27 of the 30 patients (90%). Twenty-five of twenty-seven symptomatic patients (93%) were on acid suppression therapy. The majority of our patients (70%) remained unchanged regarding their endoscopic status over 5 years. Progression to erosive esophagitis occurred in four patients with Los Angeles (LA) A (13%), three patients with LA B (10%), and two patients with LA C (7%). The presence of pathological acid exposure did not alter the presence of reflux symptoms over 5 years. Disease progression to erosive esophagitis occurred more frequently in patients with pathological acid exposure than those without pathological acid exposure (P= 0.025). Most NERD patients have symptoms and require acid suppression therapy 5 years after their initial diagnosis. Initial pathological acid exposure does not influence the use of acid suppression; however, it does influence the progression of NERD within 5 years of follow-up.

  11. Formic acid measurements from space: Retrieval strategy, evaluation, and initial constraints on primary and secondary sources

    NASA Astrophysics Data System (ADS)

    Millet, D. B.; Chaliyakunnel, S.; Wells, K. C.; Cady-Pereira, K. E.; Shephard, M. W.; Luo, M.; Paulot, F.

    2012-12-01

    Formic acid is a major contributor to acidity in the global atmosphere, and recent work suggests that its sources are significantly underestimated. New space-borne measurements from the Tropospheric Emission Spectrometer (TES), onboard EOS Aura, offer valuable global data for investigating this issue, and for quantifying primary and secondary formic acid sources to the atmosphere. In this presentation, we describe the TES formic acid retrieval strategy along with a series of sensitivity studies to test its reliability. We present initial global results showing the seasonal and spatial distribution of formic acid in the lower troposphere, and apply a 3D chemical transport model (GEOS-Chem) to i) evaluate the TES retrievals against a collection of airborne and ground-based observations, and ii) assess what constraints the satellite data can provide on the budget of atmospheric formic acid.

  12. Nucleic acid and protein synthesis during lateral root initiation in Marsilea quadrifolia (Marsileaceae)

    NASA Technical Reports Server (NTRS)

    Lin, B. L.; Raghavan, V.

    1991-01-01

    The pattern of DNA, RNA, and protein synthesis during lateral root initiation in Marsilea quadrifolia L. was monitored by autoradiography of incorporated of 3H-thymidine, 3H-uridine, and 3H-leucine, respectively. DNA synthesis was associated with the enlargement of the lateral root initial prior to its division. Consistent with histological studies, derivatives of the lateral root initial as well as the cells of the adjacent inner cortex and pericycle of the parent root also continued to synthesize DNA. RNA and protein synthetic activities were found to be higher in the lateral root initials than in the endodermal initials of the same longitudinal layer. The data suggest a role for nucleic acid and protein synthesis during cytodifferentiation of a potential endodermal cell into a lateral root initial.

  13. Nucleic acid and protein synthesis during lateral root initiation in Marsilea quadrifolia (Marsileaceae)

    NASA Technical Reports Server (NTRS)

    Lin, B. L.; Raghavan, V.

    1991-01-01

    The pattern of DNA, RNA, and protein synthesis during lateral root initiation in Marsilea quadrifolia L. was monitored by autoradiography of incorporated of 3H-thymidine, 3H-uridine, and 3H-leucine, respectively. DNA synthesis was associated with the enlargement of the lateral root initial prior to its division. Consistent with histological studies, derivatives of the lateral root initial as well as the cells of the adjacent inner cortex and pericycle of the parent root also continued to synthesize DNA. RNA and protein synthetic activities were found to be higher in the lateral root initials than in the endodermal initials of the same longitudinal layer. The data suggest a role for nucleic acid and protein synthesis during cytodifferentiation of a potential endodermal cell into a lateral root initial.

  14. Sex specific retinoic acid signaling is required for the initiation of urogenital sinus bud development

    PubMed Central

    Bryant, Sarah L.; Francis, Jeffrey C.; Lokody, Isabel B.; Wang, Hong; Risbridger, Gail P.; Loveland, Kate L.; Swain, Amanda

    2014-01-01

    The mammalian urogenital sinus (UGS) develops in a sex specific manner, giving rise to the prostate in the male and the sinus vagina in the embryonic female. Androgens, produced by the embryonic testis, have been shown to be crucial to this process. In this study we show that retinoic acid signaling is required for the initial stages of bud development from the male UGS. Enzymes involved in retinoic acid synthesis are expressed in the UGS mesenchyme in a sex specific manner and addition of ligand to female tissue is able to induce prostate-like bud formation in the absence of androgens, albeit at reduced potency. Functional studies in mouse organ cultures that faithfully reproduce the initiation of prostate development indicate that one of the roles of retinoic acid signaling in the male is to inhibit the expression of Inhba, which encodes the βA subunit of Activin, in the UGS mesenchyme. Through in vivo genetic analysis and culture studies we show that inhibition of Activin signaling in the female UGS leads to a similar phenotype to that of retinoic acid treatment, namely bud formation in the absence of androgens. Our data also reveals that both androgens and retinoic acid have extra independent roles to that of repressing Activin signaling in the development of the prostate during fetal stages. This study identifies a novel role for retinoic acid as a mesenchymal factor that acts together with androgens to determine the position and initiation of bud development in the male UGS epithelia. PMID:25261715

  15. Living carbocationic polymerization of isobutylene by epoxide/Lewis acid systems: The mechanism of initiation

    NASA Astrophysics Data System (ADS)

    Hayat Soytas, Serap

    The objective of the work presented in this dissertation was to generate a fundamental understanding of the synthesis of star-branched polyisobutylenes (PIBs) arising from hexaepoxysqualene (HES)/Lewis acid (LA) initiating systems, using BCl3 and TiCl4 as LAs. The understanding of initiation and propagation mechanisms by HES is crucial to control the number of arms and arm lengths of star PIBs expected from this initiator. The initiation by monofunctional epoxides, such as alpha-methylstyrene epoxide (MSE), 1,2-epoxy-2,4,4-trimethylpentane (TMPO-1), and 2,3-epoxy-2,4,4-trimethylpentane (TMPO-2), was investigated. In situ FTIR spectroscopy, which was highly utilized in this research, provided valuable information. Most importantly, the ability to identify the head group by in situ FTIR of growing PIB chains initiated by an epoxide, i.e. the --C--O--LA complex, contributed significantly to the understanding of initiation of IB polymerization. This technique allowed the monitoring of the rate of initiation with the multifunctional epoxy initiator. Previous research showed that TiCl4 gave 40% initiating efficiency in conjunction with the aromatic epoxy initiator MSE, whereas the aliphatic initiators TMPO-1 and TMPO-2 gave only 3 and 10% efficiency, respectively. In this research it was found that BCl3 is more efficient with the aliphatic initiator, TMPO-1, yielding an asymmetric telechelic PIB carrying an alpha-primary OH and an o-tertiary Cl functional group with 70% initiator efficiency, while MSE gave only 1--4% efficiency. The TMPO-2/BCl3 system gave 20% initiator efficiency. The various initiation mechanisms were discussed. IB polymerization was successfully initiated by HES in the presence of excess BCl3 and monitored by in situ FTIR spectroscopy. The gradual increase of the IR band assigned to the --C--O--BCl 2 group demonstrated that slow initiation was occurring. Chain extension with the HES/BCl3 initiated PIB was achieved leading to high molecular weight PIBs

  16. Initiation of Ripening in Bartlett Pear with an Antiauxin alpha(p-Chlorophenoxy)isobutyric Acid.

    PubMed

    Frenkel, C; Haard, N F

    1973-10-01

    A vacuum infiltration technique was used to apply an anti-auxin, alpha-(p-chlorophenoxy) isobutyric acid to mature green pears (Pyrus communis var. Bartlett). Application of alpha-(p-chlorophenoxy) isobutyric acid, at 0.02, 0.2, and 2.0 mm progressively accelerated the onset of chlorophyll degradation, softening, and CO(2) evolution. The action of alpha(p-chlorophenoxy) isobutyric acid is apparently independent of ethylene, since the auxin analogue depressed ethylene evolution and could overcome ethylene deficiency in fruit ripening under hypobaric conditions.The auxin analogue decreased the Michaelis constant of indoleacetic acid oxidase in vitro, suggesting that the antiauxin action of alpha-(p-chlorophenoxy) isobutyric acid is the acceleration in the breakdown of endogenous auxins in fruit and subsequently the initiation of ripening.

  17. Initial pH of medium affects organic acids production but do not affect phosphate solubilization.

    PubMed

    Marra, Leandro M; de Oliveira-Longatti, Silvia M; Soares, Cláudio R F S; de Lima, José M; Olivares, Fabio L; Moreira, Fatima M S

    2015-06-01

    The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP). The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici), UFLA03-09 (Acinetobacter sp.), UFLA03-10 (Paenibacillus kribbensis), UFLA03-106 (Paenibacillus kribbensis) and UFLA03-116 (Paenibacillus sp.). The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO4)2 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO4)2 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization.

  18. Initial pH of medium affects organic acids production but do not affect phosphate solubilization

    PubMed Central

    Marra, Leandro M.; de Oliveira-Longatti, Silvia M.; Soares, Cláudio R.F.S.; de Lima, José M.; Olivares, Fabio L.; Moreira, Fatima M.S.

    2015-01-01

    The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP). The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici), UFLA03-09 (Acinetobacter sp.), UFLA03-10 (Paenibacillus kribbensis), UFLA03-106 (Paenibacillus kribbensis) and UFLA03-116 (Paenibacillus sp.). The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO4)2 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO4)2 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization. PMID:26273251

  19. Innovative use of a bacterial enzyme involved in sialic acid degradation to initiate sialic acid biosynthesis in glycoengineered insect cells

    PubMed Central

    Geisler, Christoph; Jarvis, Donald L.

    2012-01-01

    The baculovirus/insect cell system is widely used for recombinant protein production, but it is suboptimal for recombinant glycoprotein production because it does not provide sialylation, which is an essential feature of many glycoprotein biologics. This problem has been addressed by metabolic engineering, which has extended endogenous insect cell N-glycosylation pathways and enabled glycoprotein sialylation by baculovirus/insect cell systems. However, further improvement is needed because even the most extensively engineered baculovirus/insect cell systems require media supplementation with N-acetylmannosamine, an expensive sialic acid precursor, for efficient recombinant glycoprotein sialylation. Our solution to this problem focused on E. coli N-acetylglucosamine-6-phosphate 2′-epimerase (GNPE), which normally functions in bacterial sialic acid degradation. Considering that insect cells have the product, but not the substrate for this enzyme, we hypothesized that GNPE might drive the reverse reaction in these cells, thereby initiating sialic acid biosynthesis in the absence of media supplementation. We tested this hypothesis by isolating transgenic insect cells expressing E. coli GNPE together with a suite of mammalian genes needed for N-glycoprotein sialylation. Various assays showed that these cells efficiently produced sialic acid, CMP-sialic acid, and sialylated recombinant N-glycoproteins even in growth media without N-acetylmannosamine. Thus, this study demonstrated that a eukaryotic recombinant protein production platform can be glycoengineered with a bacterial gene, that a bacterial enzyme which normally functions in sialic acid degradation can be used to initiate sialic acid biosynthesis, and that insect cells expressing this enzyme can produce sialylated N-glycoproteins without N-acetylmannosamine supplementation, which will reduce production costs in glycoengineered baculovirus/insect cell systems. PMID:23022569

  20. EVALUATION OF INTERSPECIES DIFFERENCES IN PHARMACOKINETICS (PK) USING A PBPK MODEL FOR THE PESTICIDE DIMETHYLARSINIC ACID (DMAV)

    EPA Science Inventory

    DMAV is an organoarsenical pesticide registered for use on certain citrus crops and as a cotton defoliant. In lifetime oral route studies in rodents, DMAV causes statistically significant increases in bladder tumors in rats, but not in mice. We have developed a PBPK model for D...

  1. EVALUATION OF INTERSPECIES DIFFERENCES IN PHARMACOKINETICS (PK) USING A PBPK MODEL FOR THE PESTICIDE DIMETHYLARSINIC ACID (DMAV)

    EPA Science Inventory

    DMAV is an organoarsenical pesticide registered for use on certain citrus crops and as a cotton defoliant. In lifetime oral route studies in rodents, DMAV causes statistically significant increases in bladder tumors in rats, but not in mice. We have developed a PBPK model for D...

  2. Glucocorticoids modulate amino acid-induced translation initiation in human skeletal muscle.

    PubMed

    Liu, Zhenqi; Li, Guolian; Kimball, Scot R; Jahn, Linda A; Barrett, Eugene J

    2004-08-01

    Amino acids are unique anabolic agents in that they nutritively signal to mRNA translation initiation and serve as substrates for protein synthesis in skeletal muscle. Glucocorticoid excess antagonizes the anabolic action of amino acids on protein synthesis in laboratory animals. To examine whether excessive glucocorticoids modulate mixed amino acid-signaled translation initiation in human skeletal muscle, we infused an amino acid mixture (10% Travasol) systemically to 16 young healthy male volunteers for 6 h in the absence (n = 8) or presence (n = 8) of glucocorticoid excess (dexamethasone 2 mg orally every 6 h for 3 days). Vastus lateralis muscles were biopsied before and after amino acid infusion, and the phosphorylation of eukaryotic initiation factor (eIF) 4E-binding protein 1 (4E-BP1), ribosomal protein S6 kinase (p70(S6K)), and eIF2alpha and the guanine nucleotide exchange activity of eIF2B were measured. Systemic infusion of mixed amino acids significantly stimulated the phosphorylation of 4E-BP1 (P < 0.04) and p70(S6K) (P < 0.001) and the dephosphorylation of eIF2alpha (P < 0.003) in the control group. Dexamethasone treatment did not alter the basal phosphorylation state of 4E-BP1, p70(S6K), or eIF2alpha; however, it abrogated the stimulatory effect of amino acid infusion on the phosphorylation of 4E-BP1 (P = 0.31) without affecting amino acid-induced phosphorylation of p70(S6K) (P = 0.002) or dephosphorylation of eIF2alpha (P = 0.003). Neither amino acid nor dexamethasone treatment altered the guanine nucleotide exchange activity of eIF2B. We conclude that changes of amino acid concentrations within the physiological range stimulate mRNA translation by enhancing the binding of mRNA to the 43S preinitiation complex, and the activity of p70(S6K) and glucocorticoid excess blocks the former action in vivo in human skeletal muscle.

  3. Targeting metastasis-initiating cells through the fatty acid receptor CD36.

    PubMed

    Pascual, Gloria; Avgustinova, Alexandra; Mejetta, Stefania; Martín, Mercè; Castellanos, Andrés; Attolini, Camille Stephan-Otto; Berenguer, Antoni; Prats, Neus; Toll, Agustí; Hueto, Juan Antonio; Bescós, Coro; Di Croce, Luciano; Benitah, Salvador Aznar

    2017-01-05

    The fact that the identity of the cells that initiate metastasis in most human cancers is unknown hampers the development of antimetastatic therapies. Here we describe a subpopulation of CD44(bright) cells in human oral carcinomas that do not overexpress mesenchymal genes, are slow-cycling, express high levels of the fatty acid receptor CD36 and lipid metabolism genes, and are unique in their ability to initiate metastasis. Palmitic acid or a high-fat diet specifically boosts the metastatic potential of CD36(+) metastasis-initiating cells in a CD36-dependent manner. The use of neutralizing antibodies to block CD36 causes almost complete inhibition of metastasis in immunodeficient or immunocompetent orthotopic mouse models of human oral cancer, with no side effects. Clinically, the presence of CD36(+) metastasis-initiating cells correlates with a poor prognosis for numerous types of carcinomas, and inhibition of CD36 also impairs metastasis, at least in human melanoma- and breast cancer-derived tumours. Together, our results indicate that metastasis-initiating cells particularly rely on dietary lipids to promote metastasis.

  4. Integrated Title V/acid rain permits: Transitioning through initial permit issuance and reopenings

    SciTech Connect

    Bloomfield, C.

    1995-12-31

    Titles IV and V of the Clean Air Act Amendments of 1990 (Act or CAA) created two new stationary source permitting programs, one specific to acid rain (Title IV), and a second for operating permits in general (Title V). The Phase 2 portion of the acid rain program was designed to be implemented through the Title V operating permit program, thereby subjecting all Phase 2 acid rain sources to the requirements of Title V. Permits issued pursuant to Phase 2 of the acid rain program will be viewed as a self-contained portion of the Title V operating permit and will be governed by regulations promulgated under both Title IV and Title V. The requirements imposed by Title IV may not always be consistent with the broader operating permit program requirements of Title V, and when inconsistency occurs, the acid rain requirements will take precedence. This nonalignment will perhaps be most apparent during two stages of initial permitting: (1) the transition period following Title V program approval when permit application, issuance, and effective dates differ between the two programs, and (2) at the point when acid rain permits must be reopened to incorporate Phase 2 NO{sub x} requirements. This paper explores strategies for streamlining implementation of the two programs with particular focus on these two coordination issues.

  5. Comparative Transcriptomics Reveals Jasmonic Acid-Associated Metabolism Related to Cotton Fiber Initiation

    PubMed Central

    Wang, Liman; Zhu, Youmin; Hu, Wenjing; Zhang, Xueying; Cai, Caiping; Guo, Wangzhen

    2015-01-01

    Analysis of mutants and gene expression patterns provides a powerful approach for investigating genes involved in key stages of plant fiber development. In this study, lintless-fuzzless XinWX and linted-fuzzless XinFLM with a single genetic locus difference for lint were used to identify differentially expressed genes. Scanning electron microscopy showed fiber initiation in XinFLM at 0 days post anthesis (DPA). Fiber transcriptional profiling of the lines at three initiation developmental stages (-1, 0, 1 DPA) was performed using an oligonucleotide microarray. Loop comparisons of the differentially expressed genes within and between the lines was carried out, and functional classification and enrichment analysis showed that gene expression patterns during fiber initiation were heavily associated with hormone metabolism, transcription factor regulation, lipid transport, and asparagine biosynthetic processes, as previously reported. Further, four members of the allene-oxide cyclase (AOC) family that function in jasmonate biosynthesis were parallel up-regulation in fiber initiation, especially at -1 DPA, compared to other tissues and organs in linted-fuzzed TM-1. Real time-quantitative PCR (RT-qPCR) analysis in different fiber mutant lines revealed that AOCs were up-regulated higher at -1 DPA in lintless-fuzzless than that in linted-fuzzless and linted-fuzzed materials, and transcription of the AOCs was increased under jasmonic acid (JA) treatment. Expression analysis of JA biosynthesis-associated genes between XinWX and XinFLM showed that they were up-regulated during fiber initiation in the fuzzless-lintless mutant. Taken together, jasmonic acid-associated metabolism was related to cotton fiber initiation. Parallel up-regulation of AOCs expression may be important for normal fiber initiation development, while overproduction of AOCs might disrupt normal fiber development. PMID:26079621

  6. Initiation Temperature for Runaway Tri-n-Butyl Phosphate/Nitric Acid Reaction

    SciTech Connect

    Rudisill, T.S.

    2000-11-28

    During a review of the H-Canyon authorization basis, Defense Nuclear Facility Safety Board (DNFSB) staff members questioned the margin of safety associated with a postulated tri-n-butyl phosphate (TBP)/nitric acid runaway reaction due to the inadvertent heating of a canyon tank containing greater than 3000 lbs (1362 kg) of TBP. The margin of safety was partially based on experiments and calculations performed by the Actinide Technology Section (ATS) to support deletion of indication of tank agitation as a Safety Class System. In the technical basis for deletion of this system, ATS personnel conservatively calculated the equilibrium temperature distribution of a canyon tank containing TBP and nitric acid layers which were inadvertently heated by a steam jet left on following a transfer. The maximum calculated temperature (128 degrees C) was compared to the minimum initiation temperature for a runaway reaction (greater than 130 degrees C) documented by experimental work in the mid 195 0s. In this work, the initiation temperature as a function of nitric acid concentration was measured for 0 and 20 wt percent dissolved solids. The DNFSB staff members were concerned that data for 0 wt percent dissolved solids were not conservative given the facts that data for 20 wt percent dissolved solids show initiation temperatures at or below 130 degrees C and H-Canyon solutions normally contained a small amount of dissolved solids.

  7. Effect of initial solution pH on photo-induced reductive decomposition of perfluorooctanoic acid.

    PubMed

    Qu, Yan; Zhang, Chao-Jie; Chen, Pei; Zhou, Qi; Zhang, Wei-Xian

    2014-07-01

    The effects of initial solution pH on the decomposition of perfluorooctanoic acid (PFOA) with hydrated electrons as reductant were investigated. The reductive decomposition of PFOA depends strongly on the solution pH. In the pH range of 5.0-10.0, the decomposition and defluorination rates of PFOA increased with the increase of the initial solution pH. The rate constant was 0.0295 min(-1) at pH 10.0, which was more than 49.0 times higher than that at pH 5.0. Higher pH also inhibits the generation of toxic intermediates during the PFOA decomposition. For example, the short-chain PFCAs reached a lower maximum concentration in shorter reaction time as pH increasing. The peak areas of accumulated fluorinated and iodinated hydrocarbons detected by GC/MS under acidic conditions were nearly 10-100 times more than those under alkaline conditions. In short, alkaline conditions were more favorable for photo-induced reduction of PFOA as high pH promoted the decomposition of PFOA and inhibited the accumulation of intermediate products. The concentration of hydrated electron, detected by laser flash photolysis, increased with the increase of the initial pH. This was the main reason why the decomposition of PFOA in the UV-KI system depended strongly on the initial pH. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Genomic-wide analysis of BEAS-2B cells exposed to Trivalent Arsenicals and Dimethylthioarsinic acid

    EPA Science Inventory

    Lung is a major target for arsenic carcinogenesis in humans by both oral and inhalation routes. However, the carcinogenic mode of action of arsenicals is unknown. We investigated the effects of inorganic arsenic (iAsIII), monomethylarsonous acid (MMAIII), dimethylarsinous acid (D...

  9. Genomic-wide analysis of BEAS-2B cells exposed to Trivalent Arsenicals and Dimethylthioarsinic acid

    EPA Science Inventory

    Lung is a major target for arsenic carcinogenesis in humans by both oral and inhalation routes. However, the carcinogenic mode of action of arsenicals is unknown. We investigated the effects of inorganic arsenic (iAsIII), monomethylarsonous acid (MMAIII), dimethylarsinous acid (D...

  10. Chemisorption of Perfluorooctanoic Acid on Powdered Activated Carbon Initiated by Persulfate in Aqueous Solution.

    PubMed

    Sun, Bo; Ma, Jun; Sedlak, David L

    2016-07-19

    Perfluorooctanoic acid (PFOA) is a perfluorocarboxylic acid that is difficult to treat by most conventional methods. As a result, it is often removed from solution by adsorption on powdered activated carbon (PAC), followed by incineration of the spent carbon. To provide a new approach for treatment, PFOA was exposed to sulfate radicals (SO4(-•)) produced by thermolysis of persulfate (S2O8(2-)) in the presence of PAC. Under acidic conditions, thermal activation of persulfate resulted in transformation of PFOA to shorter-chain-length perfluorinated compounds, as previously reported. However, when thermolysis of persulfate occurred under circumneutral pH conditions in the presence of PAC, a new removal pathway for PFOA was observed. Under these conditions, the removal of PFOA was attributable to chemisorption, a process in which PAC catalyzed persulfate decomposition and reacted with the transformation products to produce covalently bound PFOA. At PAC concentrations between 200 and 1000 mg/L and an initial PFOA concentration of 0.5 μM, covalent bonding resulted in removal of 10-40% of the PFOA. Under these conditions, the process resulted in removal of more than half of a more hydrophilic perfluoroalkyl acid (i.e., perfluorobutanoic acid, PFBA), which was greater than the amount of PFBA removed by physical adsorption on PAC. Although the high reaction temperatures (i.e., 80 °C) and relatively high doses of PAC used in this study may be impractical for drinking water treatment, this process may be applied to the treatment of these recalcitrant compounds in industrial wastewater, reverse osmosis concentrate, and other waters that contain high concentrations of PFOA and other perfluorocarboxylic acids.

  11. Initiation Temperature for Runaway Tri-n-Butyl Phosphate/Nitric Acid Reaction

    SciTech Connect

    Rudisill, T.S.

    2001-09-14

    In a review of the safety basis for solvent extraction processes at the Department of Energy's Savannah River Site, a question was raised concerning the safety margin associated with a postulated accident involving a runaway tri-n-butyl phosphate (TBP)/nitric acid reaction due to the inadvertent heating of a tank. The safety margin was based on studies which showed the maximum temperature would not exceed 128 degrees Celsius compared to 130 degrees Celsius, the minimum initiation temperature for runaway reaction established in the 1950's following damaging incidents at the Savannah River and Hanford Sites. The reviewers were concerned the minimum temperature was not conservative since data for solutions containing 20 wt percent dissolved solids showed initiation temperatures at or below 130 degrees Celsius and process solutions normally contain some dissolved solids.

  12. Ethosuximide, Valproic Acid and Lamotrigine in Childhood Absence Epilepsy: Initial Monotherapy Outcomes at 12 months

    PubMed Central

    Glauser, Tracy A.; Cnaan, Avital; Shinnar, Shlomo; Hirtz, Deborah G.; Dlugos, Dennis; Masur, David; Clark, Peggy O.; Adamson, Peter C.

    2012-01-01

    Purpose Determine the optimal initial monotherapy for children with newly diagnosed childhood absence epilepsy based on 12 months of double blind therapy. Methods A double-blind, randomized controlled clinical trial compared the efficacy, tolerability and neuropsychological effects of ethosuximide, valproic acid and lamotrigine in children with newly diagnosed childhood absence epilepsy. Study medications were titrated to clinical response and subjects remained in the trial unless they reached a treatment failure criterion. Maximal target doses were ethosuximide 60 mg/kg/day or 2000 mg/day, valproic acid 60 mg/kg/day or 3000 mg/day and lamotrigine 12 mg/kg/day or 600 mg/day. Original primary outcome was at 16–20 weeks and included a video EEG assessment. For this report, the main effectiveness outcome was the freedom from failure rate 12 months after randomization and included a video EEG assessment; differential drug effects were determined by pairwise comparisons. The main cognitive outcome was the percentage of subjects experiencing attentional dysfunction at the Month 12 visit. Key Findings A total of 453 children were enrolled and randomized; seven were deemed ineligible and 446 subjects comprised the overall efficacy cohort. There were no demographic differences between the three cohorts. By 12 months after starting therapy, only 37% of all enrolled subjects were free from treatment failure on their first medication. At the Month 12 visit, the freedom-from-failure rates for ethosuximide and valproic acid were similar (45% and 44%, respectively; odds ratio with valproic acid vs. ethosuximide, 0.94; 95% confidence interval [CI], 0.60 to 1.48; P = 0.82) and were higher than the rate for lamotrigine (21%; odds ratio with ethosuximide vs. lamotrigine, 3.09; 95% CI, 1.86 to 5.13; odds ratio with valproic acid vs. lamotrigine, 2.90; 95% CI, 1.74 to 4.83; P<0.001 for both comparisons). The frequency of treatment failures due to lack of seizure control (p < 0

  13. Amino acids augment muscle protein synthesis in neonatal pigs during acute endotoxemia by stimulating mTOR-dependent translation initiation

    USDA-ARS?s Scientific Manuscript database

    In skeletal muscle of adults, sepsis reduces protein synthesis by depressing translation initiation and induces resistance to branched-chain amino acid stimulation. Normal neonates maintain a high basal muscle protein synthesis rate that is sensitive to amino acid stimulation. In the present study...

  14. Initial test of the silicic acid leakage hypothesis using sedimentary biomarkers

    NASA Astrophysics Data System (ADS)

    Higginson, Matthew J.; Altabet, Mark A.

    2004-09-01

    Several mechanisms have been proposed for large CO2 changes at glacial Terminations, including shifting the CaCO3:Corg rain ratio by changing surface water nutrient supply, altering the balance between diatom and coccolithophore production. Diatom Si:N is highest in Fe-stressed high-latitude waters. Southern Ocean Fe enrichment studies suggest diatom Si demands reduced under Fe-replete (glacial) conditions, allowing increased silicic acid to leak northward in subducted intermediate water and upwell at lower latitudes. We test this `Silicic Acid Leakage' hypothesis using relative abundances of phytoplankton-specific biomarkers in Peru margin sediments spanning 0-20 Ka. Results indicate increased coccolithophorid:diatom production from ~0.5 to 3 between 18.0-15.5 Ka. Temporal correlation with the initial pCO2 rise and early deglacial shift in mode water ventilation implicates a coincidental, possibly causative reorganization of Sub-Antarctic Mode Water formation and reduced Fe abundance. However, coccolithophorid production subsequently declined, suggesting rain ratio changes were only partly responsible for the CO2 deglacial transition.

  15. Auxin Controls Arabidopsis Adventitious Root Initiation by Regulating Jasmonic Acid Homeostasis[W

    PubMed Central

    Gutierrez, Laurent; Mongelard, Gaëlle; Floková, Kristýna; Păcurar, Daniel I.; Novák, Ondřej; Staswick, Paul; Kowalczyk, Mariusz; Păcurar, Monica; Demailly, Hervé; Geiss, Gaia; Bellini, Catherine

    2012-01-01

    Vegetative shoot-based propagation of plants, including mass propagation of elite genotypes, is dependent on the development of shoot-borne roots, which are also called adventitious roots. Multiple endogenous and environmental factors control the complex process of adventitious rooting. In the past few years, we have shown that the auxin response factors ARF6 and ARF8, targets of the microRNA miR167, are positive regulators of adventitious rooting, whereas ARF17, a target of miR160, is a negative regulator. We showed that these genes have overlapping expression profiles during adventitious rooting and that they regulate each other’s expression at the transcriptional and posttranscriptional levels by modulating the homeostasis of miR160 and miR167. We demonstrate here that this complex network of transcription factors regulates the expression of three auxin-inducible Gretchen Hagen3 (GH3) genes, GH3.3, GH3.5, and GH3.6, encoding acyl-acid-amido synthetases. We show that these three GH3 genes are required for fine-tuning adventitious root initiation in the Arabidopsis thaliana hypocotyl, and we demonstrate that they act by modulating jasmonic acid homeostasis. We propose a model in which adventitious rooting is an adaptive developmental response involving crosstalk between the auxin and jasmonate regulatory pathways. PMID:22730403

  16. Retinoic acid derived from the fetal ovary initiates meiosis in mouse germ cells.

    PubMed

    Mu, Xinyi; Wen, Jing; Guo, Meng; Wang, Jianwei; Li, Ge; Wang, Zhengpin; Wang, Yijing; Teng, Zhen; Cui, Yan; Xia, Guoliang

    2013-03-01

    Meiotic initiation of germ cells at 13.5 dpc (days post-coitus) indicates female sex determination in mice. Recent studies reveal that mesonephroi-derived retinoic acid (RA) is the key signal for induction of meiosis. However, whether the mesonephroi is dispensable for meiosis is unclear and the role of the ovary in this meiotic process remains to be clarified. This study provides data that RA derived from fetal ovaries is sufficient to induce germ cell meiosis in a fetal ovary culture system. When fetal ovaries were collected from 11.5 to 13.5 dpc fetuses, isolated and cultured in vitro, germ cells enter meiosis in the absence of mesonephroi. To exclude RA sourcing from mesonephroi, 11.5 dpc urogenital ridges (UGRs; mesonephroi and ovary complexes) were treated with diethylaminobenzaldehyde (DEAB) to block retinaldehyde dehydrogenase (RALDH) activity in the mesonephros and the ovary. Meiosis occurred when DEAB was withdrawn and the mesonephros was removed 2 days later. Furthermore, RALDH1, rather than RALDH2, serves as the major RA synthetase in UGRs from 12.5 to 15.5 dpc. DEAB treatment to the ovary alone was able to block germ cell meiotic entry. We also found that exogenously supplied RA dose-dependently reduced germ cell numbers in ovaries by accelerating the entry into meiosis. These results suggest that ovary-derived RA is responsible for meiosis initiation.

  17. Retinoic acid availability drives the asynchronous initiation of spermatogonial differentiation in the mouse.

    PubMed

    Snyder, Elizabeth M; Small, Christopher; Griswold, Michael D

    2010-11-01

    Throughout the reproductive lifespan of most male mammals, sperm production is constant because of the regulated differentiation of spermatogonia. Retinoic acid (RA) and a downstream target, Stra8, are required for complete spermatogenesis. To examine the role of RA in initiating spermatogonial differentiation, a transgenic mouse model expressing beta-galactosidase under the control of an RA response element was used. Cells in the neonatal testis undergoing active RA signaling were visualized by beta-galactosidase activity, the relationship between RA and differentiation determined, and the role of RA-degrading enzymes in regulating RA demonstrated. Beta-galactosidase activity was found to be predominantly associated with differentiating, premeiotic germ cells and to be distributed nonuniformly throughout the seminiferous tubules. Additionally, beta-galactosidase activity in premeiotic germ cells colocalized with STRA8 protein and was induced in germ cells with exogenous RA treatment. The RA-degrading enzyme, CYP26B1, was found to have germ cell localization and nonuniform distribution between tubules via immunohistochemistry. Treatment with a CYP26 enzyme inhibitor resulted in an increased number of germ cells with both beta-galactosidase activity and STRA8 protein and an increase in the expression of genes associated with differentiation and reduced expression of a gene associated with undifferentiated germ cells. These results show the action of RA in a subset of spermatogonia leads to nonuniform initiation of differentiation throughout the neonatal testis, potentially mediated through the action of CYP26 enzymes. Thus, the presence of RA is a likely driving factor in the initiation of spermatogonial differentiation and may result in asynchronous spermatogenesis.

  18. Modification of N-Methyl-N-Nitrosourea initiated bladder carcinogenesis in Wistar rats by terephthalic acid

    SciTech Connect

    Cui Lunbiao; Shi Yuan; Dai Guidong; Pan Hongxin; Chen Jianfeng; Song Ling; Wang Shouling; Chang, Hebron C.; Sheng Hongbing; Wang Xinru . E-mail: xrwang@njmu.edu.cn

    2006-01-15

    The effect of terephthalic acid (TPA) on urinary bladder carcinogenesis was examined. Male Wistar rats were initiated by injection of N-Methyl-N-Nitrosourea (MNU) (20 mg/kg b.w. ip) twice a week for 4 weeks, then given basal diet containing 5% TPA, 5% TPA plus 4% Sodium bicarbonate (NaHCO{sub 3}) or 1% TPA for the next 22 weeks, and then euthanized. 5% TPA treatment induced a high incidence of urinary bladder calculi and a large amount of precipitate. Though 5% TPA plus 4% Sodium bicarbonate (NaHCO{sub 3}) and 1% TPA treatment did not induce urinary bladder calculi formation, they resulted in a moderate increase in urinary precipitate. Histological examination of urinary bladder revealed that MNU-5% TPA treatment resulted in a higher incidence of simple hyperplasia, papillary or nodular hyperplasia (PN hyperplasia), papilloma and cancer than MNU control. MNU-5% TPA plus 4% Sodium bicarbonate (NaHCO{sub 3}) and 1% TPA treatment increased slightly the incidence of simple hyperplasia and PN hyperplasia (not statistically significant). The major elements of the precipitate are phosphorus, potassium, sulfur, chloride, calcium and TPA. The present study indicated that the calculi induced by TPA had a strong promoting activity on urinary bladder carcinogenesis and the precipitate containing calcium terephthalate (CaTPA) may also have weak promoting activity on urinary bladder carcinogenesis.

  19. Effects of molecular weight of grafted hyaluronic acid on wear initiation.

    PubMed

    Lee, Dong Woog; Banquy, Xavier; Das, Saurabh; Cadirov, Nicholas; Jay, Gregory; Israelachvili, Jacob

    2014-05-01

    Hyaluronic acid (HA) of different molecular weights (Mw) was grafted onto mica surfaces to study the effects of Mw on the conformation and wear protection properties of a grafted HA (gHA) layer in lubricin (LUB) and bovine synovial fluid (BSF) using a surface forces apparatus. The Mw of gHA had significant effects on the wear pressure (Pw), at which point the wear initiates. Increasing the gHA Mw from 51 to 2590kDa increased Pw from 4 to 8MPa in LUB and from 15 to 31MPa in BSF. The 2590kDa gHA in BSF had the best wear protection (Pw∼31MPa), even though it exhibited the highest friction coefficient (μ∼0.35), indicating that a low μ does not necessarily result in good wear protection, as is often assumed. The normal force profile indicated that BSF confines the gHA structure, making it polymer brush-like, commonly considered as an excellent structure for boundary lubrication.

  20. Early Folic Acid Supplement Initiation and Risk of Adverse Early Childhood Respiratory Health: A Population-based Study.

    PubMed

    Alfonso, Vivian H; Bandoli, Gretchen; von Ehrenstein, Ondine; Ritz, Beate

    2017-09-08

    Objectives Folate plays a vital role in biologic functions yet women often do not meet the recommended dietary intake in pregnancy. It has been suggested that high folic acid intake during pregnancy may increase the risk of respiratory diseases in offspring. However, findings from observational studies in human populations are inconclusive. Methods In this population-based study, we collected self-reported folic acid and prenatal vitamin supplement use during pregnancy 3-6 months postpartum from mothers in Los Angeles whose children were born in 2003. Supplement initiation was based on whichever supplement, either folic acid or prenatal supplements, the women initiated first. In a 2006 follow-up survey, approximately 50% of women were re-contacted to gather information on the child's respiratory health, including symptoms and diagnoses, at approximately 3.5 years of age. Results Overall, timing of folic acid supplement initiation was not associated with wheeze or lower respiratory tract infection, even after accounting for preterm births and censoring at follow-up. However, children born to mothers with a history of atopy (hay fever, eczema or asthma) who initiate folic acid supplements in late pregnancy, compared to first trimester initiators, have 1.67 (95% CI 1.12, 2.49) times the risk of wheeze in the first 3 years of life and 1.88 (95% CI 1.05, 3.34) times the risk of wheeze in the past year. No association was found among children of non-atopic mothers. Conclusions These findings suggest that early folic acid or prenatal supplementation among atopic women may be important to prevent wheeze among offspring.

  1. Initial uptake and insulin releasing action of chloromercuribenzene-p-sulphonic acid (CMBS) in suspensions of pancreatic islet cells.

    PubMed

    Idahl, L A; Lernmark, A; Söderberg, M; Winblad, B

    1980-04-01

    The effects of chloromercuribenzene-p-sulphonic acid on dispersed cells prepared from beta-cell-rich ob/ob-mouse islets were studied. 1) Chloromercuribenzene-p-sulphonic acid at concentrations of 0.1 mmol/l or higher diminished cell viability which was partially counteracted by increasing concentrations of bovine serum albumin. 2) The uptake of 203Hg-chloromercuribenzene-p-sulphonic acid after incubation for 4 seconds or longer showed that most of the non-toxic concentrations of chloromercuribenzene-p-sulphonic acid was bound to the cell within 40 seconds. Maximal uptake was achieved after 3 minutes of incubation. The uptake of radioactive chloromercuribenzene-p-sulphonic acid was inhibited by bovine serum albumin. 3) The dynamics of insulin release from perifused dispersed beta-cells embedded in fibrin showed a maximal 40--50-fold stimulation by 0.03 mmol/l chloromercuribenzene-p-sulphonic acid within 10 minutes of perifusion. 4) Scanning electron microscopy of beta-cells revealed no major changes in the cell surface under conditions of maximal binding and insulin releasing effects of chloromercuribenzene-p-sulphonic acid. These data support the concept that the ability of chloromercuribenzene-p-sulphonic acid to induce insulin release is related to its initial binding to the beta-cell surface. The binding of chloromercuribenzene-p-sulphonic acid and the subsequent release of insulin seem to occur without major changes in beta-cell surface morphology.

  2. Digital Isothermal Quantification of Nucleic Acids via Simultaneous Chemical Initiation of Recombinase Polymerase Amplification Reactions on SlipChip

    PubMed Central

    Shen, Feng; Davydova, Elena K.; Du, Wenbin; Kreutz, Jason E.; Piepenburg, Olaf; Ismagilov, Rustem F.

    2011-01-01

    In this paper, digital quantitative detection of nucleic acids was achieved at the single-molecule level by chemical initiation of over one thousand sequence-specific, nanoliter, isothermal amplification reactions in parallel. Digital polymerase chain reaction (digital PCR), a method used for quantification of nucleic acids, counts the presence or absence of amplification of individual molecules. However it still requires temperature cycling, which is undesirable under resource-limited conditions. This makes isothermal methods for nucleic acid amplification, such as recombinase polymerase amplification (RPA), more attractive. A microfluidic digital RPA SlipChip is described here for simultaneous initiation of over one thousand nL-scale RPA reactions by adding a chemical initiator to each reaction compartment with a simple slipping step after instrument-free pipette loading. Two designs of the SlipChip, two-step slipping and one-step slipping, were validated using digital RPA. By using the digital RPA SlipChip, false positive results from pre-initiation of the RPA amplification reaction before incubation were eliminated. End-point fluorescence readout was used for “yes or no” digital quantification. The performance of digital RPA in a SlipChip was validated by amplifying and counting single molecules of the target nucleic acid, Methicillin-resistant Staphylococcus aureus (MRSA) genomic DNA. The digital RPA on SlipChip was also tolerant to fluctuations of the incubation temperature (37–42 °C), and its performance was comparable to digital PCR on the same SlipChip design. The digital RPA SlipChip provides a simple method to quantify nucleic acids without requiring thermal cycling or kinetic measurements, with potential applications in diagnostics and environmental monitoring under resource-limited settings. The ability to initiate thousands of chemical reactions in parallel on the nanoliter scale using solvent-resistant glass devices is likely to be useful for

  3. Two-stage magnetic orientation of uric acid crystals as gout initiators

    NASA Astrophysics Data System (ADS)

    Takeuchi, Y.; Miyashita, Y.; Mizukawa, Y.; Iwasaka, M.

    2014-01-01

    The present study focuses on the magnetic behavior of uric acid crystals, which are responsible for gout. Under a sub-Tesla (T)-level magnetic field, rotational motion of the crystals, which were caused by diamagnetic torque, was observed. We used horizontal magnetic fields with a maximum magnitude of 500 mT generated by an electromagnet to observe the magnetic orientation of the uric acid microcrystals by a microscope. The uric acid crystals showed a perpendicular magnetic field orientation with a minimum threshold of 130 mT. We speculate that the distinct diamagnetic anisotropy in the uric acid crystals resulted in their rotational responses.

  4. [Amoxicillin and clavulanic acid versus amoxicillin plus gentamicin in the empirical initial treatment of urinary tract infections in hospitalized patients].

    PubMed

    Verzasconi, R; Rodoni, P; Monotti, R; Marone, C; Mombelli, G

    1995-08-19

    We compared the fixed combination amoxicillin plus clavulanic acid with that of amoxicillin plus gentamicin in the empirical initial treatment of severe urinary tract infections. The study included 87 hospitalized patients (51 women and 36 men, mean age 58 +/- 22 years) with acute uncomplicated pyelonephritis (n = 48) or with complicated urinary tract infections (n = 39). 80 patients (92%) had fever and 31 patients (36%) positive blood cultures. 45 patients were randomly assigned to amoxicillin plus clavulanic acid and 42 to amoxicillin plus gentamicin. Overall, 18 patients (21%) were infected with organisms resistant in vitro to amoxicillin plus clavulanic acid, whereas no pathogen was isolated with resistance to amoxicillin plus gentamicin (p < 0.0001). At the end of the empirical treatment (4.2 +/- 1.5 days after the start), significant bacteriuria was present in 6/39 patients (15%) assigned to amoxicillin plus clavulanic acid, compared to 0/34 patients assigned to amoxicillin plus gentamicin (p < 0.05). The clinical response was satisfactory in both groups, and the time from start of therapy to resolution of fever was 2.2 +/- 1.4 days in the amoxicillin plus clavulanic acid group and 2.3 +/- 1.7 days in the amoxicillin plus gentamicin group. Although the in-vitro resistance did not result in a lower clinical efficacy of amoxicillin plus clavulanic acid compared to amoxicillin plus gentamicin in our relatively small sample of patients, the data indicate that the antimicrobial activity of amoxicillin plus clavulanic acid is inadequate to cover the spectrum of causative agents in hospitalized patients with pyelonephritis or complicated urinary tract infections. Amoxicillin plus clavulanic acid should therefore not be used in the initial empirical treatment of these infections.

  5. Digital isothermal quantification of nucleic acids via simultaneous chemical initiation of recombinase polymerase amplification reactions on SlipChip.

    PubMed

    Shen, Feng; Davydova, Elena K; Du, Wenbin; Kreutz, Jason E; Piepenburg, Olaf; Ismagilov, Rustem F

    2011-05-01

    In this paper, digital quantitative detection of nucleic acids was achieved at the single-molecule level by chemical initiation of over one thousand sequence-specific, nanoliter isothermal amplification reactions in parallel. Digital polymerase chain reaction (digital PCR), a method used for quantification of nucleic acids, counts the presence or absence of amplification of individual molecules. However, it still requires temperature cycling, which is undesirable under resource-limited conditions. This makes isothermal methods for nucleic acid amplification, such as recombinase polymerase amplification (RPA), more attractive. A microfluidic digital RPA SlipChip is described here for simultaneous initiation of over one thousand nL-scale RPA reactions by adding a chemical initiator to each reaction compartment with a simple slipping step after instrument-free pipet loading. Two designs of the SlipChip, two-step slipping and one-step slipping, were validated using digital RPA. By using the digital RPA SlipChip, false-positive results from preinitiation of the RPA amplification reaction before incubation were eliminated. End point fluorescence readout was used for "yes or no" digital quantification. The performance of digital RPA in a SlipChip was validated by amplifying and counting single molecules of the target nucleic acid, methicillin-resistant Staphylococcus aureus (MRSA) genomic DNA. The digital RPA on SlipChip was also tolerant to fluctuations of the incubation temperature (37-42 °C), and its performance was comparable to digital PCR on the same SlipChip design. The digital RPA SlipChip provides a simple method to quantify nucleic acids without requiring thermal cycling or kinetic measurements, with potential applications in diagnostics and environmental monitoring under resource-limited settings. The ability to initiate thousands of chemical reactions in parallel on the nanoliter scale using solvent-resistant glass devices is likely to be useful for a broader

  6. Crosstalk between DnaA Protein, the Initiator of Escherichia coli Chromosomal Replication, and Acidic Phospholipids Present in Bacterial Membranes

    PubMed Central

    Saxena, Rahul; Fingland, Nicholas; Patil, Digvijay; Sharma, Anjali K.; Crooke, Elliott

    2013-01-01

    Anionic (i.e., acidic) phospholipids such as phosphotidylglycerol (PG) and cardiolipin (CL), participate in several cellular functions. Here we review intriguing in vitro and in vivo evidence that suggest emergent roles for acidic phospholipids in regulating DnaA protein-mediated initiation of Escherichia coli chromosomal replication. In vitro acidic phospholipids in a fluid bilayer promote the conversion of inactive ADP-DnaA to replicatively proficient ATP-DnaA, yet both PG and CL also can inhibit the DNA-binding activity of DnaA protein. We discuss how cellular acidic phospholipids may positively and negatively influence the initiation activity of DnaA protein to help assure chromosomal replication occurs once, but only once, per cell-cycle. Fluorescence microscopy has revealed that PG and CL exist in domains located at the cell poles and mid-cell, and several studies link membrane curvature with sub-cellular localization of various integral and peripheral membrane proteins. E. coli DnaA itself is found at the cell membrane and forms helical structures along the longitudinal axis of the cell. We propose that there is cross-talk between acidic phospholipids in the bacterial membrane and DnaA protein as a means to help control the spatial and temporal regulation of chromosomal replication in bacteria. PMID:23595001

  7. Initiation of Deoxyribonucleic Acid Replication in Germinating Spores of Bacillus subtilis 168 Carrying the dnaB(Ts)134 Mutation

    PubMed Central

    Callister, Heather; Mesurier, Sue Le; Wake, R. G.

    1977-01-01

    The nature of the deoxyribonucleic acid synthesis reported by others to occur at 45°C in germinating spores of the temperature-sensitive deoxyribonucleic acid initiation mutant of Bacillus subtilis 168, TsB134, has been investigated. Density transfer experiments, using 5-bromouracil, show that a normal round of replication can occur in a significant fraction of the spore population under such conditions. No repair synthesis is detectable. The possibility raised by this finding, that initiation of the first round of replication during spore outgrowth is unique in that its initiation is determined prior to germination, has been investigated by comparing the behavior of germinating spores of isogenic strains of B. subtilis 168, one carrying and the other without the dnaB (Ts)134 mutation. It is shown that deoxyribonucleic acid synthesis in the Ts strain is very sensitive to temperature in the vicinity of 45°C. At a slightly higher temperature, 49°C, initiation of the first round of replication in the Ts strain is completely (greater than 96%) blocked, but it proceeds normally in the Ts+ strain. Thus, it is concluded that, after the germination of a spore, the action of the dnaB134 gene product is an obligatory requirement for initiation of the first round of replication. The initiation of replication that can occur in spores of the original TsB134 strain germinating at 45°C is presumably due to incomplete inactivation of the dnaB134 gene product under such conditions. PMID:405369

  8. Modification of amino acids at shock pressures of 3 to 30 GPA: Initial results

    NASA Technical Reports Server (NTRS)

    Peterson, Etta; Horz, Friedrich; Haynes, Gerald; See, Thomas

    1991-01-01

    Since the discovery of amino acids in the Murchison meteorite, much speculation has focused on their origin and subsequent alteration, including the possible role of secondary processes, both terrestrial and extraterrestrial. As collisional processes and associated shock waves seem to have affected the silicate portions of many primitive meteorites, a mixture of powdered Allende (125-150 m grain size) and nine synthetic amino acids (six protein and three nonprotein) were subjected to controlled shock pressures from 3 to 30 GPa to determine the effect of shocks on amino acid survivability. Preliminary characterizations of the recovered shock products are presented.

  9. An aminotransferase from Lactococcus lactis initiates conversion of amino acids to cheese flavor compounds.

    PubMed Central

    Yvon, M; Thirouin, S; Rijnen, L; Fromentier, D; Gripon, J C

    1997-01-01

    The enzymatic degradation of amino acids in cheese is believed to generate aroma compounds and therefore to be involved in the complex process of cheese flavor development. In lactococci, transamination is the first step in the degradation of aromatic and branched-chain amino acids which are precursors of aroma compounds. Here, the major aromatic amino acid aminotransferase of a Lactococcus lactis subsp. cremoris strain was purified and characterized. The enzyme transaminates the aromatic amino acids, leucine, and methionine. It uses the ketoacids corresponding to these amino acids and alpha-ketoglutarate as amino group acceptors. In contrast to most bacterial aromatic aminotransferases, it does not act on aspartate and does not use oxaloacetate as second substrate. It is essential for the transformation of aromatic amino acids to flavor compounds. It is a pyridoxal 5'-phosphate-dependent enzyme and is composed of two identical subunits of 43.5 kDa. The activity of the enzyme is optimal between pH 6.5 and 8 and between 35 and 45 degrees C, but it is still active under cheese-ripening conditions. PMID:9023921

  10. Genetic Examination of Initial Amino Acid Oxidation and Glutamate Catabolism in the Hyperthermophilic Archaeon Thermococcus kodakarensis

    PubMed Central

    Yokooji, Yuusuke; Sato, Takaaki; Fujiwara, Shinsuke; Imanaka, Tadayuki

    2013-01-01

    Amino acid catabolism in Thermococcales is presumed to proceed via three steps: oxidative deamination of amino acids by glutamate dehydrogenase (GDH) or aminotransferases, oxidative decarboxylation by 2-oxoacid:ferredoxin oxidoreductases (KOR), and hydrolysis of acyl-coenzyme A (CoA) by ADP-forming acyl-CoA synthetases (ACS). Here, we performed a genetic examination of enzymes involved in Glu catabolism in Thermococcus kodakarensis. Examination of amino acid dehydrogenase activities in cell extracts of T. kodakarensis KUW1 (ΔpyrF ΔtrpE) revealed high NADP-dependent GDH activity, along with lower levels of NAD-dependent activity. NADP-dependent activities toward Gln/Ala/Val/Cys and an NAD-dependent threonine dehydrogenase activity were also detected. In KGDH1, a gene disruption strain of T. kodakarensis GDH (Tk-GDH), only threonine dehydrogenase activity was detected, indicating that all other activities were dependent on Tk-GDH. KGDH1 could not grow in a medium in which growth was dependent on amino acid catabolism, implying that Tk-GDH is the only enzyme that can discharge the electrons (to NADP+/NAD+) released from amino acids in their oxidation to 2-oxoacids. In a medium containing excess pyruvate, KGDH1 displayed normal growth, but higher degrees of amino acid catabolism were observed compared to those for KUW1, suggesting that Tk-GDH functions to suppress amino acid oxidation and plays an anabolic role under this condition. We further constructed disruption strains of 2-oxoglutarate:ferredoxin oxidoreductase and succinyl-CoA synthetase. The two strains displayed growth defects in both media compared to KUW1. Succinate generation was not observed in these strains, indicating that the two enzymes are solely responsible for Glu catabolism among the multiple KOR and ACS enzymes in T. kodakarensis. PMID:23435976

  11. LC-MS/MS analysis of plasma polyunsaturated fatty acids in type 2 diabetic patients after insulin analog initiation therapy

    PubMed Central

    2013-01-01

    Background Eicosanoids derived from omega-6 (n6) polyunsaturated fatty acids (PUFAs) have proinflammatory functions whereas eicosanoids derived from omega-3 (n3) PUFAs have anti-inflammatory properties. This study was designed to evaluate the effect of insulin analog initiation therapy on n6 and n3 PUFAs in type 2 diabetic patients during early phase. Methods Sixteen type 2 diabetic patients with glycosylated hemoglobin (HbA1c) levels above 10% despite ongoing combination therapy with sulphonylurea and metformin were selected. Former treatment regimen was continued for the first day followed by substitution of sulphonylurea therapy with different insulin analogs (0.4 U/kg/day) plus metformin. Blood samples were obtained from all patients at 24 and 72 hours. Plasma levels of arachidonic acid (AA, C20:4n6), dihomo-gamma-linolenic acid (DGLA, C20:3n6), eicosapentaenoic acid (EPA, C20:5n3) and docosahexaenoic acid (DHA, C22:6n3) were determined by an optimized multiple reaction monitoring (MRM) method using ultra fast-liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). Prostaglandin E2 (PGE2) was measured in serum samples by enzyme immunoassay. Results All measured PUFAs were significantly increased after treatment with insulin analogs plus metformin compared to before treatment levels. The mean AA/EPA ratio was significantly lower after treatment with insulin analogs plus metformin. A 22% decrease was observed in PGE2 levels after treatment with insulin analogs plus metformin compared to pretreatment levels (p > 0.05). Conclusion The significant decrease in AA/EPA ratio indicates that insulin analog initiation therapy has anti-inflammatory properties by favoring the increase of n3 fatty acid EPA. PMID:24195588

  12. Nucleotide sequence of wheat germ cytoplasmic initiator methionine transfer ribonucleic acid.

    PubMed Central

    Ghosh, H P; Ghosh, K; Simsek, M; RajBhandary, U L

    1982-01-01

    The primary sequence of wheat germ initiator tRNA has been determined using in vitro labelling techniques. The sequence is: pAUCAGAGUm1Gm2GCGCAG CGGAAGCGUm2GG psi GGGCCCAUt6AACCCACAGm7GDm5Cm5CCAGGA psi CGm1AAACCUG*GCUCUGAUACCAOH. As in other eukaryotic initiator tRNAs, the sequence -T psi CG(A)- present in loop IV of virtually all tRNA active in protein synthesis is absent and is replaced by -A psi CG-. The base pair G2:C71 present in all other initiator tRNAs recognized by E. coli Met-tRNA transformylase is absent and is replaced by U2:A71. Since wheat germ initiator tRNA is not formylated by E. coli Met-tRNA transformylase this implies a possible role of the G2:C71 base pair present in other initiator tRNAs in formylation of initiator tRNA species. Images PMID:6808465

  13. Sunlight-initiated chemistry of aqueous pyruvic acid: building complexity in the origin of life.

    PubMed

    Griffith, Elizabeth C; Shoemaker, Richard K; Vaida, Veronica

    2013-10-01

    Coupling chemical reactions to an energy source is a necessary step in the origin of life. Here, we utilize UV photons provided by a simulated sun to activate aqueous pyruvic acid and subsequently prompt chemical reactions mimicking some of the functions of modern metabolism. Pyruvic acid is interesting in a prebiotic context due to its prevalence in modern metabolism and its abiotic availability on early Earth. Here, pyruvic acid (CH3COCOOH, a C3 molecule) photochemically reacts to produce more complex molecules containing four or more carbon atoms. Acetoin (CH3CHOHCOCH3), a C4 molecule and a modern bacterial metabolite, is produced in this chemistry as well as lactic acid (CH3CHOHCOOH), a molecule which, when coupled with other abiotic chemical reaction pathways, can provide a regeneration pathway for pyruvic acid. This chemistry is discussed in the context of plausible environments on early Earth such as near the ocean surface and atmospheric aerosol particles. These environments allow for combination and exchange of reactants and products of other reaction environments (such as shallow hydrothermal vents). The result could be a contribution to the steady increase in chemical complexity requisite in the origin of life.

  14. Sunlight-initiated Chemistry of Aqueous Pyruvic Acid: Building Complexity in the Origin of Life

    NASA Astrophysics Data System (ADS)

    Griffith, Elizabeth C.; Shoemaker, Richard K.; Vaida, Veronica

    2013-10-01

    Coupling chemical reactions to an energy source is a necessary step in the origin of life. Here, we utilize UV photons provided by a simulated sun to activate aqueous pyruvic acid and subsequently prompt chemical reactions mimicking some of the functions of modern metabolism. Pyruvic acid is interesting in a prebiotic context due to its prevalence in modern metabolism and its abiotic availability on early Earth. Here, pyruvic acid (CH3COCOOH, a C3 molecule) photochemically reacts to produce more complex molecules containing four or more carbon atoms. Acetoin (CH3CHOHCOCH3), a C4 molecule and a modern bacterial metabolite, is produced in this chemistry as well as lactic acid (CH3CHOHCOOH), a molecule which, when coupled with other abiotic chemical reaction pathways, can provide a regeneration pathway for pyruvic acid. This chemistry is discussed in the context of plausible environments on early Earth such as near the ocean surface and atmospheric aerosol particles. These environments allow for combination and exchange of reactants and products of other reaction environments (such as shallow hydrothermal vents). The result could be a contribution to the steady increase in chemical complexity requisite in the origin of life.

  15. RALDH2, the enzyme for retinoic acid synthesis, mediates meiosis initiation in germ cells of the female embryonic chickens.

    PubMed

    Yu, Minli; Yu, Ping; Leghari, Imdad H; Ge, Chutian; Mi, Yuling; Zhang, Caiqiao

    2013-02-01

    Meiosis is a process unique to the differentiation of germ cells and exhibits sex-specific in timing. Previous studies showed that retinoic acid (RA) as the vitamin A metabolite is crucial for controlling Stra8 (Stimulated by retinoic acid gene 8) expression in the gonad and to initiate meiosis; however, the mechanism by which retinoid-signaling acts has remained unclear. In the present study, we investigated the role of the enzyme retinaldehyde dehydrogenase 2 (RALDH2) which catalyzes RA synthesizes by initiating meiosis in chicken ovarian germ cells. Meiotic germ cells were first detected at day 15.5 in chicken embryo ovary when the expression of synaptonemal complex protein 3 (Scp3) and disrupted meiotic cDNA 1 homologue (Dmc1) became elevated, while Stra8 expression was specifically up-regulated at day 12.5 before meiosis onset. It was observed from the increase in Raldh2 mRNA expression levels and decreases in Cyp26b1 (the enzyme for RA catabolism) expression levels during meiosis that requirement for RA accumulation is essential to sustain meiosis. This was also revealed by RA stimulation of the cultured ovaries with the initiation of meiosis response, and the knocking down of the Raldh2 expression during meiosis, leading to abolishment of RA-dependent action. Altogether, these studies indicate that RA synthesis by the enzyme RALDH2 and signaling through its receptor is crucial for meiosis initiation in chicken embryonic ovary.

  16. An overview of the western Maryland coal combustion by-products/acid mine drainage initiative, Part 1 of 3

    SciTech Connect

    Petzrick, P.; Rafalko, L.G.; Lyons, C.

    1996-12-31

    The western Maryland coal combustion by-products (CCB)/acid mine drainage (AMD) initiative (the Initiative) is a public-private partnership exploring the use of CCBs to eliminate AMD from Maryland`s abandoned coal mines. This dynamic partnership will sponsor a series of large scale experiments and demonstrations addressing the engineering problems that characterize the beneficial application of CCBs to prevent acid formation on a scale that is consistent with the large quantity of these materials that will be produced by power plants in or near western Maryland. The initial demonstration is the filling and sealing of a small hand dug mine (the Frazee Mine) under approximately ninety feet of overburden on Winding Ridge near Friendsville, Maryland. A second demonstration is being planned for the Kempton mine complex. Subsequent demonstrations will focus on reducing the cost of materials handling and mine injection and solving the engineering problems characteristic of filling abandoned mines in Maryland. The Initiative is the flagship activity in Maryland`s overall Ash Utilization Program, the goal of which is to promote beneficial use of all coal combustion by-products.

  17. Protein immobilization onto poly(acrylic acid) functional macroporous polyHIPE obtained by surface-initiated ARGET ATRP.

    PubMed

    Audouin, Fabrice; Larragy, Ruth; Fox, Mary; O'Connor, Brendan; Heise, Andreas

    2012-11-12

    Amino-functional macroporous monoliths from polymerized high internal phase emulsion (polyHIPE) were surface modified with initiators for atom transfer radical polymerization (ATRP). The ATRP initiator groups on the polyHIPE surface were successfully used to initiate activator regeneration by electron transfer (ARGET) ATRP of (meth)acrylic monomers, such as methyl methacrylate (MMA) or tert-butyl acrylate (tBA) resulting in a dense coating of polymers on the polyHIPE surface. Addition of sacrificial initiator permitted control of the amount of polymer grafted onto the monolith surface. Subsequent removal of the tert-butyl protecting groups yielded highly functional polyHIPE-g-poly(acrylic acid). The versatility to use the high density of carboxylic acid groups for secondary reactions was demonstrated by the successful conjugation of enhanced green fluorescent protein (eGFP) and coral derived red fluorescent protein (DsRed) using EDC/sulfo-NHS chemistry, on the polymer 3D-scaffold surface. The materials and methodologies presented here are simple and robust, thus, opening new possibilities for the bioconjugation of highly porous polyHIPE for bioseparation applications.

  18. The selective reaction of methoxyamine with cytidine residues in mammalian initiator transfer ribonucleic acid

    PubMed Central

    Piper, Peter W.; Clark, Brian F.C.

    1974-01-01

    Methoxyamine reacts selectively with tRNA molecules at certain exposed cytosine residues usually located in non base-paired regions of the two dimensional clover leaf structure. Here methoxyamine is used for the first time in a study of a mammalian tRNA structure. One of the sequence abnormalities of myeloma initiator tRNA is a cytosine instead of the usual uracil immediately preceding the anticodon. A study of the reaction of the cytosine residues with methoxyamine indicates that the accessibility of bases to chemical reagents in the anticodon loop of this mammalian initiator tRNA is very similar to that observed for the bacterial initiator tRNA. Images PMID:10793658

  19. A computational study of radical initiated protein backbone homolytic dissociation on all natural amino acids.

    PubMed

    Uranga, Jon; Lakuntza, Oier; Ramos-Cordoba, Eloy; Matxain, Jon M; Mujika, Jon I

    2016-11-16

    Hydroxyl radical (˙OH) is known to be one of the most reactive species. In this work, the hydrogen abstraction by ˙OH from Cα and Cβ atoms of all amino acids is studied in the framework of density functional theory as this is the most favorable reaction mechanism when this kind of radical attacks a protein. From the myriad routes that the oxidation of a protein by a ˙OH radical may follow, fragmentation of the protein is one of the most damaging ones as it hampers the normal function of the protein. Therefore, cleavages of the Cα-C and Cα-N backbone bonds have been investigated as the second step of the mechanism. To the best of our knowledge, this is the first time that this reaction pathway has been systematically studied for all natural amino acids. The study includes the effects that the solvent dielectrics or the conformation of the peptide model employed has on the reaction. Interestingly, the results indicate that the nature of the side chain has little effect on the H abstraction reaction, and that for most of amino acids the attack at the Cα atom is favored over the attack at the Cβ atom. The origin of this preference relies on the larger capability of the formed radical intermediate to delocalize the unpaired electron, thus maximizing the captodative effect. Moreover, the reaction is more favorable when the reactant presents a β-sheet conformation, with a completely planar peptide backbone. With respect to the homolytic splitting of the Cα-C and Cα-N bonds, the former is favorable for almost all amino acids, whereas Ser and Thr are the only amino acids favoring the latter. These results agree with previous investigations but an accurate description of the electronic density analysis performed indicates that the origin of the different reaction pathway preferences relies on a large stabilization of the product rather than bond weakening at the radical intermediate.

  20. The structure of a replication initiator unites diverse aspects of nucleic acid metabolism

    PubMed Central

    Campos-Olivas, Ramón; Louis, John M.; Clérot, Danielle; Gronenborn, Bruno; Gronenborn, Angela M.

    2002-01-01

    Rolling circle replication is a mechanism for copying single-stranded genomes by means of double-stranded intermediates. A multifunctional replication inititiator protein (Rep) is indispensable for the precise initiation and termination of this process. Despite the ubiquitous presence and fundamental importance of rolling circle replication elements, structural information on their respective replication initiators is still missing. Here we present the solution NMR structure of the catalytic domain of Rep, the initiator protein of tomato yellow leaf curl virus. It is composed of a central five-stranded anti-parallel β-sheet, flanked by a small two-stranded β-sheet, a β-hairpin and two α-helices. Surprisingly, the structure reveals that the catalytic Rep domain is related to a large group of proteins that bind RNA or DNA. Identification of Rep as resembling the family of ribonucleoprotein/RNA-recognition motif fold proteins establishes a structure-based evolutionary link between RNA binding proteins, splicing factors, and replication initiators of prokaryotic and eukaryotic single-stranded DNA elements and mammalian DNA tumor viruses. PMID:12130667

  1. The Western Maryland coal combustion by-products/acid mine drainage initiative, the Winding Ridge demonstration project

    SciTech Connect

    Rafalko, L.; Petzrick, P.

    1998-12-31

    The Maryland Department of Natural Resources Power Plant Research Program (PPRP) and the Maryland Department of the Environment Bureau of Mines (MDE) have undertaken the Western Maryland Coal Combustion By-Products (CCB)/Acid Mine Drainage (AMD) Initiative, which is a joint effort with private industry to demonstrate the beneficial application of alkaline CCBs to create flowable grouts to prevent the formation of AMD. The Initiative is a key component of Maryland`s overall ash utilization program to promote and expand the beneficial use of all CCBS. Ultimately, the Initiative is targeting AMD abatement from significant AMD sources in the State, such as the Kempton Mine and Three Forks Run complexes. The Winding Ridge Project is the Initiative`s first demonstration of this technology. The Frazee Mine (a small kitchen mine), in Garrett County, Maryland, was selected for the demonstration. The CCB grout mixing and mine injection phase was performed in October and November 1996. This phase demonstrated the engineering feasibility and logistics of using 100% CCBs and acid mine water to create a grout, which was injected into the Frazee Mine. Approximately 5,600 cubic yards of CCB grout were injected into the mine under both dry and submerged conditions. Observations from borehole camera logging indicated that the grout was capable of flowing at least 100 feet along the mine pavement. Laboratory tests of hardened grout core samples recovered from the mine showed unconfined compressive strengths of over 1,000 pounds per square inch (psi) (28-day strength tests were over 300 psi) and permeabilities of about 10--7 centimeters per second. These observations indicate that the use of CCBs as a grout for mine sealing is a promising technical option for the large-scale beneficial application of these materials. Currently, postinjection water quality monitoring is being performed to better evaluate the long-term effects on the mine discharge. In addition, future work will

  2. Initiating a crystallographic analysis of recombinant (S)-2-hydroxypropylphosphonic acid epoxidase from Streptomyces wedmorensis

    SciTech Connect

    Cameron, Scott; McLuskey, Karen; Chamberlayne, Rachel; Hallyburton, Irene; Hunter, William N.

    2005-05-01

    The gene encoding the unusual metal-ion-dependent epoxidase involved in fosfomycin biosynthesis, S. wedmorensis (S)-2-hydroxypropylphosphonic acid epoxidase, has been cloned and the protein expressed, purified and crystallized. Two crystal forms have been obtained, one of which diffracts to high resolution. The oxirane (1R,2S)-1,2-epoxypropylphosphonic acid (fosfomycin) is a natural product antibiotic produced in Streptomyces wedmorensis by the metal-ion-dependent (S)-2-hydroxypropylphosphonic acid epoxidase. This epoxidase is highly unusual since it has no requirement for a haem prosthetic group. The gene encoding the enzyme, fom4, has been cloned and a highly efficient recombinant source of the enzyme established. Two different crystal forms, tetragonal and hexagonal, have been obtained. The hexagonal form displays symmetry consistent with space group P6{sub 1/5}22 and unit-cell parameters a = 86.44, c = 221.56 Å, γ = 120°. The Matthews coefficient, V{sub M}, of 2.7 Å{sup 3} Da{sup −1} corresponds to two subunits, each of approximate weight 21.4 kDa, in the asymmetric unit with 55% solvent content. These crystals diffract to high resolution and experimental phases are being sought to determine the structure.

  3. Development of fatty acid calcium stone ileus after initiation of human milk fortifier.

    PubMed

    Murase, Masahiko; Miyazawa, Tokuo; Taki, Motohiro; Sakurai, Motoichiro; Miura, Fumihiro; Mizuno, Katsumi; Itabashi, Kazuo; Toki, Akira

    2013-02-01

    We report a case who was born with extremely low birth weight infant and had experienced abdominal operation for necrotizing enterocolitis, eventually developed ileus due to fatty acid calcium stones after giving human milk fortifier. He had developed necrotizing enterocolitis on day 30 of his age, such that we performed enterectomy and ileostomy. He could not tolerate enteral feeding fully, because intestinal fistula infection was repeated. Although we administered hindmilk, he grew up slowly and he suffered cholestasis as well. We performed end-to-end anastomosis to prevent fistula infections on day 87. After this operation, breast milk feeding volume was increased easily. However, we started to add HMF of half-strength on day 124, because his body weight gain remained very poor. And we confirmed to intensify the ratio of HMF full-strength on day 128. After that his abdomen had distended on day 131. As there is no effect of conservative therapy to occlusive ileus, we did emergency laparotomy on day 139. Intestinal calculi were impacted at anastomic portion. Although all stones were removed, he died on 144 days due to disseminated intravascular coagulation and renal failure. Calculi analysis revealed that all of them were fatty acid calcium stones. There is no report about like our case. We speculate that the construction of fatty acid calcium result from either high concentration of calcium/phosphorus or rapid increase in the fortification. We could have prevented this case happened by slower increment of fortification.

  4. Synergism and effect of high initial volatile fatty acid concentrations during food waste and pig manure anaerobic co-digestion.

    PubMed

    Dennehy, Conor; Lawlor, Peadar G; Croize, Thomas; Jiang, Yan; Morrison, Liam; Gardiner, Gillian E; Zhan, Xinmin

    2016-10-01

    Anaerobic co-digestion of food waste (FW) and pig manure (PM) was undertaken in batch mode at 37°C in order to identify and quantify the synergistic effects of co-digestion on the specific methane yield (SMY) and reaction kinetics. The effects of the high initial volatile fatty acid (VFA) concentrations in PM on synergy observed during co-digestion, and on kinetic modelling were investigated. PM to FW mixing ratios of 1/0, 4/1, 3/2, 2/3, 1/4 and 0/1 (VS basis) were examined. No VFA or ammonia inhibition was observed. The highest SMY of 521±29ml CH4/gVS was achieved at a PM/FW mixing ratio of 1/4. Synergy in terms of both reaction kinetics and SMY occurred at PM/FW mixing ratios of 3/2, 2/3 and 1/4. Initial VFA concentrations did not explain the synergy observed. Throughout the study the conversion of butyric acid was inhibited. Due to the high initial VFA content of PM, conventional first order and Gompertz models were inappropriate for determining reaction kinetics. A dual pooled first order model was found to provide the best fit for the data generated in this study. The optimal mixing ratio in terms of both reaction kinetics and SMY was found at a PM/FW mixing ratio of 1/4.

  5. Simulation of Initial Stages of the Methanol to Gasoline Process in Acidic Zeolites

    NASA Astrophysics Data System (ADS)

    Stich, I.; Hytha, M.; Gale, J. D.; Terakura, K.; Payne, M. C.

    2000-03-01

    Methanol to gasoline process is one of the most studied applications of zeolites in current commercial production. This complex process involves: (1) initial adsorption of methanol in the zeolite, (2) activation of the adsorbed methanol molecules, (3) formation of the first intermediates (dimethyl ether (DME)), (4) formation of the first -C-C- bonds. Extensive studies of the stages (1)-(3) have been performed using the method of ab initio molecular dynamics (within DFT in the GGA approximation) and the method of thermodynamic integration to compute the free energy profile for formation of the first intermediate. We find that the initial adsorption (physisorption vs. chemisorption) depends on the adsorption conditions such as zeolite framework and methanol loading. Under certain combination of these conditions the chemisorbed species undergo activation. The activated species are very susceptible to nucleophilic attack to form DME. The computed free energy profile shows that this reaction is entropically controlled with significant differences between the total and free energy profiles.

  6. Synthesis of carboxymethylcellulose/acrylic acid hydrogels with superabsorbent properties by radiation-initiated crosslinking

    NASA Astrophysics Data System (ADS)

    Fekete, Tamás; Borsa, Judit; Takács, Erzsébet; Wojnárovits, László

    2016-07-01

    Superabsorbent hydrogels were prepared by gamma irradiation from aqueous solutions of carboxymethylcellulose (CMC) and acrylic acid (AAc) with varying CMC:AAc ratio. By partially replacing the CMC with AAc the gelation increased and led to a higher gel fraction and lower water uptake. Moreover, the gelation required significantly milder synthesis conditions. Decreasing both the dose and the solute concentration in the presence of AAc led to gels with higher gel fraction and higher degree of swelling compared to pure CMC gels. Increasing the AAc content up to 10% proved to be very effective, while very high AAc content (over 50%) hindered the gelation process.

  7. Arsenate and dimethylarsinic acid in drinking water did not affect DNA damage repair in urinary bladder transitional cells or micronuclei in bone marrow

    EPA Science Inventory

    Arsenic is a recognized human skin, lung, and urinary bladder carcinogen, and may act as a cocarcinogen in the urinary bladder (with cigarette smoking) and skin (with UV light exposure). Possible modes of action of arsenic carcinogenesis/cocarcinogenesis include induction of DNA ...

  8. Arsenate and dimethylarsinic acid in drinking water did not affect DNA damage repair in urinary bladder transitional cells or micronuclei in bone marrow

    EPA Science Inventory

    Arsenic is a recognized human skin, lung, and urinary bladder carcinogen, and may act as a cocarcinogen in the urinary bladder (with cigarette smoking) and skin (with UV light exposure). Possible modes of action of arsenic carcinogenesis/cocarcinogenesis include induction of DNA ...

  9. [Acne conglobata: personality and psychological sequelae in 13-cis-retinoic acid therapy. Initial results].

    PubMed

    Studt, H H; Riehl, A; Gollnick, H

    1986-05-15

    16 patients suffering from acne conglobata were prospectively examined by means of analytical interviews and 5 psychometric procedures before and 6 months after oral treatment with 13-cis retinoic acid (isotretinoin). In comparison with a control group of psychosomatic patients, acne conglobata patients are more frequently affected by childhood influences leading to a neurotic personality structure already before the outbreak of acne; the patients more often complain of disturbed social contact, depressive moods, or general disorders. After successful treatment with isotretinoin, we observed augmented self-confidence and positive aggressiveness, on one hand, and increase of anxiety depressive moods, and general complaints, on the other. These effects are not drug related in a pharmacological way. These observations suggest the influence of psychic factors in the pathogenesis of acne conglobata. Regarding the medical management of these patients, it should be considered that psychic and psychosomatic disorders might be intensified after successful drug therapy.

  10. The OH-initiated oxidation of atmospheric peroxyacetic acid: Experimental and model studies

    NASA Astrophysics Data System (ADS)

    Wu, Huihui; Wang, Yin; Li, Huan; Huang, Liubin; Huang, Dao; Shen, Hengqing; Xing, Yanan; Chen, Zhongming

    2017-09-01

    Peroxyacetic acid (PAA, CH3C(O)OOH) plays an important role in atmospheric chemistry, serving as reactive oxidant and affecting radical recycling. However, previous studies revealed an obvious gap between modelled and observed concentrations of atmospheric PAA, which may be partly ascribed to the uncertainty in the kinetics and mechanism of OH-oxidation. In this study, we measured the rate constant of OH radical reaction with PAA (kPAA+OH) and investigated the products in order to develop a more robust atmospheric PAA chemistry. Using the relative rates technique and employing toluene and meta-xylene as reference compounds, the kPAA+OH was determined to be (9.4-11.9) × 10-12 cm3 molecule-1 s-1 at 298 K and 1 atm, which is about (2.5-3.2) times larger than that parameter used in Master Chemical Mechanism v3.3.1 (MCM v3.3.1) (3.70 × 10-12 cm3 molecule-1 s-1). Incorporation of a box model and MCM v3.3.1 with revised PAA chemistry represented a better simulation of atmospheric PAA observed during Wangdu Campaign 2014, a rural site in North China Plain. It is found that OH-oxidation is an important sink of atmospheric PAA in this rural area, accounting for ∼30% of the total loss. Moreover, the major terminal products of PAA-OH reaction were identified as formaldehyde (HCHO) and formic acid (HC(O)OH). The modelled results show that both primary and secondary chemistry play an important role in the large HCHO and HC(O)OH formation under experimental conditions. There should exist the channel of methyl H-abstraction for PAA-OH reaction, which may also provide routes to HCHO and HC(O)OH formation.

  11. Sialic acid mediates the initial binding of positively charged inorganic particles to alveolar macrophage membranes.

    PubMed

    Gallagher, J E; George, G; Brody, A R

    1987-06-01

    Pulmonary macrophages phagocytize inhaled particles and are postulated to play a role in the development of pulmonary interstitial fibrogenesis. The basic biologic mechanisms through which inhaled particles bind to macrophage membranes and subsequently are phagocytized remain unclear. We hypothesize that positively charged particles bind to negatively charged sialic acid (SA) residues on macrophage membranes. Alveolar Macrophages (AM) were collected by saline lavage from normal rat lungs. The cells adhered to plastic coverslips in serum-free phosphate buffered saline at 37 degrees C for 45 min and then were maintained at 4 degrees C for the binding experiments. Even distribution of SA groups on AM surfaces was demonstrated by scanning electron microscopy of wheat germ agglutinin (WGA) conjugated to 50 nm gold spheres. The WGA is a lectin that binds specifically to sialic acid, and pretreatment of AM with this lectin prevented the binding of positively charged carbonyl iron (C-Fe) spheres, aluminum (Al) spheres, and chrysotile asbestos fibers to AM surfaces. Limulus protein, another lectin with binding specificity for SA, similarly blocked the binding of positively charged spheres and chrysotile asbestos fibers but not negatively charged glass spheres or crocidolite asbestos fibers. Con A and ricin, lectins that bind to mannose and galactose residues, respectively, did not block particle binding. When both positively charged iron spheres and negatively charged glass spheres were prebound to AM membranes, subsequent treatment with WGA displaced only the positively charged spheres from macrophage surfaces. Con A and ricin had no effect on prebound positively charged C-Fe and Al spheres.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. A strong inorganic acid-initiated methacrylate polymerization strategy for room temperature preparation of monolithic columns for capillary electrochromatography.

    PubMed

    Wang, Man-Man; Wang, He-Fang; Jiang, Dong-Qing; Wang, Shan-Wei; Yan, Xiu-Ping

    2010-05-01

    A facile strong inorganic acid-initiated methacrylate polymerization strategy was developed for fabricating monolithic columns at room temperature. The prepared monoliths were characterized by FTIR spectrometry, mercury intrusion porosimeter and SEM, while their performance was evaluated by CEC for the separation of various types of compounds including alkyl benzenes, polycyclic aromatic hydrocarbons, nonsteroidal anti-inflammatory drugs, anilines, and nitrophenol isomers. The column-to-column and batch-to-batch reproducibility for the prepared monoliths in terms of the RSD of EOF flow velocity, retention factor, and the minimum plate height of naphthalene ranged from 3.4 to 12.4%. The fabricated monoliths gave excellent performance for the separation of the test neutral compounds with the theoretical plates of 170,000-232,000 plates per meter for thiourea, and 77,400-112,300 plates per meter for naphthalene. The proposed strong inorganic acid-initiated methacrylate polymerization strategy is a promising alternative for fabricating organic polymer-based monoliths.

  13. Cytotoxic, genotoxic and cell-cycle disruptive effects of thio-dimethylarsinate in cultured human cells and the role of glutathione

    SciTech Connect

    Ochi, Takafumi Kita, Kayoko; Suzuki, Toshihide; Rumpler, Alice; Goessler, Walter; Francesconi, Kevin A.

    2008-04-01

    Thio-dimethylarsinate (thio-DMA), a recently discovered urine metabolite in humans, was investigated for its cytotoxic, genotoxic and cell-cycle disruptive effects in the cultured human hepatocarcinoma cell line, HepG2, and Syrian hamster embryo cells. In addition, the role of glutathione (GSH) on the cytotoxic effects of thio-DMA was investigated in terms of the effects of GSH depletion and the effects of exogenously added GSH. LC{sub 50} values of arsenicals for cells incubated for 48 h were 0.026 mM for thio-DMA, 0.343 mM for DMA and 3.66 mM for dithio-DMA. Depletion of cell GSH reduced the cytotoxic effects of thio-DMA. The cytotoxic effects of 0.02 mM and 0.05 mM thio-DMA were enhanced markedly when used in combination with 1 to 3 mM GSH, but decreased again when combined with 5 mM GSH. These results suggested that cytotoxic intermediates were generated by the interaction of thio-DMA with GSH, while an excessive amount of GSH suppressed the generation of these intermediates. Flow-cytometry showed that thio-DMA was an inducer of cells with 4N DNA and hypo 2N DNA. The results also demonstrated that cells arrested in the mitotic phase had abnormalities in their spindle organization and centrosome integrity. In addition, cells arrested in mitosis by thio-DMA had chromosome structural aberrations, such as chromatid gaps, chromatid breaks and chromatid exchanges. Moreover, the cytotoxic effects of thio-DMA may in part be associated with an apoptotic mode of cell death that was evaluated by the appearance of nucleosome level DNA fragmentations and an 85-kDa cleavage fragment of poly (ADP-ribose) polymerase. These findings suggest that the presence of thio-DMA in human urine has implications for human health in terms of arsenic metabolism and toxicity.

  14. Valproic acid induces differentiation and transient tumor regression, but spares leukemia-initiating activity in mouse models of APL.

    PubMed

    Leiva, M; Moretti, S; Soilihi, H; Pallavicini, I; Peres, L; Mercurio, C; Dal Zuffo, R; Minucci, S; de Thé, H

    2012-07-01

    Aberrant histone acetylation was physiopathologically associated with the development of acute myeloid leukemias (AMLs). Reversal of histone deacetylation by histone deacetylase inhibitor (HDACis) activates a cell death program that allows tumor regression in mouse models of AMLs. We have used several models of PML-RARA-driven acute promyelocytic leukemias (APLs) to analyze the in vivo effects of valproic acid, a well-characterized HDACis. Valproic acid (VPA)-induced rapid tumor regression and sharply prolonged survival. However, discontinuation of treatment was associated to an immediate relapse. In vivo, as well as ex vivo, VPA-induced terminal granulocytic differentiation. Yet, despite full differentiation, leukemia-initiating cell (LIC) activity was actually enhanced by VPA treatment. In contrast to all-trans retinoic acid (ATRA) or arsenic, VPA did not degrade PML-RARA. However, in combination with ATRA, VPA synergized for PML-RARA degradation and LIC eradication in vivo. Our studies indicate that VPA triggers differentiation, but spares LIC activity, further uncouple differentiation from APL clearance and stress the importance of PML-RARA degradation in APL cure.

  15. Proteome changes in the initial bacterial colonist during ecological succession in an acid mine drainage biofilm community.

    PubMed

    Mueller, Ryan S; Dill, Brian D; Pan, Chongle; Belnap, Christopher P; Thomas, Brian C; VerBerkmoes, Nathan C; Hettich, Robert L; Banfield, Jillian F

    2011-08-01

    Proteomes of acid mine drainage biofilms at different stages of ecological succession were examined to understand microbial responses to changing community membership. We evaluated the degree of reproducibility of the community proteomes between samples of the same growth stage and found stable and predictable protein abundance patterns across time and sampling space, allowing for a set of 50 classifier proteins to be identified for use in predicting growth stages of undefined communities. Additionally, physiological changes in the dominant species, Leptospirillum Group II, were analysed as biofilms mature. During early growth stages, this population responds to abiotic stresses related to growth on the acid mine drainage solution. Enzymes involved in protein synthesis, cell division and utilization of 1- and 2-carbon compounds were more abundant in early growth stages, suggesting rapid growth and a reorganization of metabolism during biofilm initiation. As biofilms thicken and diversify, external stresses arise from competition for dwindling resources, which may inhibit cell division of Leptospirillum Group II through the SOS response. This population also represses translation and synthesizes more complex carbohydrates and amino acids in mature biofilms. These findings provide unprecedented insight into the physiological changes that may result from competitive interactions within communities in natural environments. Published 2011. This article is a US Government work and is in the public domain in the USA.

  16. Effects of initial lactic acid concentration, HRTs, and OLRs on bio-hydrogen production from lactate-type fermentation.

    PubMed

    Kim, Tae-Hyeong; Lee, Yunhee; Chang, Kwang-Hyeon; Hwang, Sun-Jin

    2012-01-01

    A batch test and continuous operation were performed to identify the effect of lactate on hydrogen production at pH 4.5. When the initial lactic acid concentration was increased from 0 to 8 g/L in the batch test, the hydrogen yield also increased from 1.41 to 1.72 mol-H2/mol-glucose. The system exhibited a long lag time and an insignificant hydrogen yield with 16 g-lactic acid/L. A continuous stirred tank reactor (CSTR) was operated at different organic loading rates (OLRs: 10, 15, 20 and 40 g/L/day) and hydraulic retention times (HRTs: 6, 12 and 24 h). At an OLR of 20 g-glucose/L/day and 12 h of HRT, the hydrogen yield was 1.2 mol-H2/mol-glucose. The yield decreased with a 24 h HRT. Even though lactate was one of the major constituents of volatile fatty acids (VFAs), hydrogen production was feasible throughout the operation. Clostridium sp. was the dominant hydrogen-producing bacteria in the system.

  17. Proteome changes in the initial bacterial colonist during ecological succession in an acid mine drainage biofilm community

    SciTech Connect

    Mueller, Ryan; Dill, Brian; Pan, Chongle; Belnap, Christopher P.; Thomas, Brian; Verberkmoes, Nathan C; Hettich, Robert {Bob} L; Banfield, Jillian F.

    2011-01-01

    Proteomes of acid mine drainage biofilms at different stages of ecological succession were examined to understand microbial responses to changing community membership. We evaluated the degree of reproducibility of the community proteomes between samples of the same growth stage and found stable and predictable protein abundance patterns across time and sampling space, allowing for a set of 50 classifier proteins to be identified for use in predicting growth stages of undefined communities. Additionally, physiological changes in the dominant species, Leptospirillum Group II, were analysed as biofilms mature. During early growth stages, this population responds to abiotic stresses related to growth on the acid mine drainage solution. Enzymes involved in protein synthesis, cell division and utilization of 1- and 2-carbon compounds were more abundant in early growth stages, suggesting rapid growth and a reorganization of metabolism during biofilm initiation. As biofilms thicken and diversify, external stresses arise from competition for dwindling resources, which may inhibit cell division of Leptospirillum Group II through the SOS response. This population also represses translation and synthesizes more complex carbohydrates and amino acids in mature biofilms. These findings provide unprecedented insight into the physiological changes that may result from competitive interactions within communities in natural environments.

  18. Fatty acid profile of the initial oral biofilm (pellicle): an in-situ study.

    PubMed

    Reich, Marco; Kümmerer, Klaus; Al-Ahmad, Ali; Hannig, Christian

    2013-09-01

    The first step of bioadhesion on dental surfaces is the formation of the acquired pellicle. This mainly acellular layer is formed instantaneously on all solid surfaces exposed to oral fluids. It is composed of proteins, glycoproteins and lipids. However, information on the lipid composition is sparse. The aim of the present study was to evaluate the fatty acid (FA) profile of the in-situ pellicle for the first time. Furthermore, the impact of rinses with safflower oil on the pellicle's FA composition was investigated. Pellicles were formed in situ on bovine enamel slabs mounted on individual upper jaw splints. The splints were carried by ten subjects over durations of 3-240 min. After comprehensive sample preparation, gas chromatography coupled with electron impact ionization mass spectrometry (GC-EI/MS) was used in order to characterize qualitatively and quantitatively a wide range of FA (C12-C24). The relative FA profiles of the pellicle samples gained from different subjects were remarkably similar, whereas the amount of FA showed significant interindividual variability. An increase in FA in the pellicle was observed over time. The application of rinses with safflower oil resulted in an accumulation of its specific FA in the pellicle. Pellicle formation is a highly selective process that does not correlate directly with salivary composition, as shown for FA.

  19. Bile acids initiate cholestatic liver injury by triggering a hepatocyte-specific inflammatory response

    PubMed Central

    Chen, Yonglin; Soroka, Carol J.; Wang, Juxian; Mennone, Albert; Wang, Yucheng; Mehal, Wajahat Z.; Jain, Dhanpat; Boyer, James L.

    2017-01-01

    Mechanisms of bile acid–induced (BA-induced) liver injury in cholestasis are controversial, limiting development of new therapies. We examined how BAs initiate liver injury using isolated liver cells from humans and mice and in-vivo mouse models. At pathophysiologic concentrations, BAs induced proinflammatory cytokine expression in mouse and human hepatocytes, but not in nonparenchymal cells or cholangiocytes. These hepatocyte-specific cytokines stimulated neutrophil chemotaxis. Inflammatory injury was mitigated in Ccl2–/– mice treated with BA or after bile duct ligation, where less hepatic infiltration of neutrophils was detected. Neutrophils in periportal areas of livers from cholestatic patients also correlated with elevations in their serum aminotransferases. This liver-specific inflammatory response required BA entry into hepatocytes via basolateral transporter Ntcp. Pathophysiologic levels of BAs induced markers of ER stress and mitochondrial damage in mouse hepatocytes. Chemokine induction by BAs was reduced in hepatocytes from Tlr9–/– mice, while liver injury was diminished both in conventional and hepatocyte-specific Tlr9–/– mice, confirming a role for Tlr9 in BA-induced liver injury. These findings reveal potentially novel mechanisms whereby BAs elicit a hepatocyte-specific cytokine-induced inflammatory liver injury that involves innate immunity and point to likely novel pathways for treating cholestatic liver disease. PMID:28289714

  20. Laboratory study on OH-initiated degradation kinetics of dehydroabietic acid.

    PubMed

    Lai, Chengyue; Liu, Yongchun; Ma, Jinzhu; Ma, Qingxin; He, Hong

    2015-04-28

    Dehydroabietic acid (DHAA) is a specific organic tracer for the pyrolysis of conifer resin. To understand its atmospheric stability, the degradation behavior of particulate DHAA in the presence of hydroxyl radicals (OH) was investigated under different environmental conditions using a stainless steel reactor with volume of 30 cm(3), in the dark. At 25 °C and 40% relative humidity (RH), the second-order rate constant (k2) of pure DHAA with OH was measured to be 5.72 ± 0.87 × 10(-12) cm(3) molecule(-1) s(-1). The influence of temperature, RH and mixing state on the degradation kinetics of DHAA were also investigated. At 40% RH, k2 of pure DHAA increases with increasing temperature and follows the Arrhenius equation k2 = (8.9 ± 1.9) × 10(-10) exp[-(1508.2 ± 64.2)/T], while RH does not have significant impact on k2 at 25 °C. At 25 °C and 40% RH, compared with pure DHAA, the corresponding k2 for DHAA mixed with (NH4)2SO4 decreased to 4.58 ± 0.95 × 10(-12) cm(3) molecule(-1) s(-1), while the value was 3.30 ± 0.79 × 10(-12) cm(3) molecule(-1) s(-1) when mixed with soot. The atmospheric lifetime of DHAA varied from 2.3 ± 0.2 to 4.4 ± 0.8 days under different environmental conditions. This study indicates that degradation of DHAA by OH radicals is appreciable, and a significant error in source apportionment should be introduced if the contribution of degradation to DHAA concentration is not considered during air mass aging.

  1. The Prebiotic C-Terminal Elongation of Peptides can be Initiated by N-Carbamoyl Amino Acids.

    PubMed

    Abou Mrad, Ninette; Ajram, Ghinwa; Rossi, Jean-Christophe; Boiteau, Laurent; Duvernay, Fabrice; Pascal, Robert; Danger, Gregoire

    2017-04-05

    The formation of peptides upon EDC promoted activation of N-carbamoylamino acids (CAA), was considered in the scope of our recent works on carbodiimide promoted C-terminus elongation of peptides in a prebiotic context. Thus EDC promoted activation of CAA derivatives of Tyr(Me) or Ala in dilute aqueous medium pH 5.5-6.5 in the presence of excess of AA, resulted in peptide formation via C-terminus activation / elongation. Kinetic results similar to those of EDC-mediated activation of N-acyl-AA lead us to postulate the formation of a 2-amino-5(4H)-oxazolone intermediate by cyclization of the activated CAA, in spite of the absence of epimerization occurred at CAA residues. Thus, in a prebiotic context, CAA may have played a similar role as N-acyl-AA in the initiation of C-terminus peptide elongation.

  2. The Aerobic Oxidation of Bromide to Dibromine Catalyzed by Homogeneous Oxidation Catalysts and Initiated by Nitrate in Acetic Acid

    SciTech Connect

    Partenheimer, Walt; Fulton, John L.; Sorensen, Christina M.; Pham, Van Thai; Chen, Yongsheng

    2014-06-01

    A small amount of nitrate, ~0.002 molal, initiates the Co/Mn catalyzed aerobic oxidation of bromide compounds (HBr,NaBr,LiBr) to dibromine in acetic acid at room temperature. At temperatures 40oC or less , the reaction is autocatalytic. Co(II) and Mn(II) themselves and mixed with ionic bromide are known homogeneous oxidation catalysts. The reaction was discovered serendipitously when a Co/Br and Co/Mn/Br catalyst solution was prepared for the aerobic oxidation of methyaromatic compounds and the Co acetate contained a small amount of impurity i.e. nitrate. The reaction was characterized by IR, UV-VIS, MALDI and EXAFS spectroscopies and the coordination chemistry is described. The reaction is inhibited by water and its rate changed by pH. The change in these variables, as well as others, are identical to those observed during homogeneous, aerobic oxidation of akylaromatics. A mechanism is proposed. Accidental addition of a small amount of nitrate compound into a Co/Mn/Br/acetic acid mixture in a large, commercial feedtank is potentially dangerous.

  3. Long-chain ω-3 fatty acid intake and endometrial cancer risk in the Women’s Health Initiative12345

    PubMed Central

    Brasky, Theodore M; Rodabough, Rebecca J; Liu, Jingmin; Kurta, Michelle L; Wise, Lauren A; Orchard, Tonya S; Cohn, David E; Belury, Martha A; White, Emily; Manson, JoAnn E; Neuhouser, Marian L

    2015-01-01

    Background: Inflammation may be important in endometrial cancer development. Long-chain ω-3 (n–3) polyunsaturated fatty acids (LCω-3PUFAs) may reduce inflammation and, therefore, reduce cancer risk. Because body mass is associated with both inflammation and endometrial cancer risk, it may modify the association of fat intake on risk. Objective: We examined whether intakes of LCω-3PUFAs were associated with endometrial cancer risk overall and stratified by body size and histologic subtype. Design: Women were n = 87,360 participants of the Women’s Health Initiative Observational Study and Clinical Trials who were aged 50–79 y, had an intact uterus, and completed a baseline food-frequency questionnaire. After 13 y of follow-up, n = 1253 incident invasive endometrial cancers were identified. Cox regression models were used to estimate HRs and 95% CIs for the association of intakes of individual ω-3 fatty acids and fish with endometrial cancer risk. Results: Intakes of individual LCω-3PUFAs were associated with 15–23% linear reductions in endometrial cancer risk. In women with body mass index (BMI; in kg/m2) <25, those in the upper compared with lowest quintiles of total LCω-3PUFA intake (sum of eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) had significantly reduced endometrial cancer risk (HR: 0.59; 95% CI: 0.40, 0.82; P-trend = 0.001), whereas there was little evidence of an association in overweight or obese women. The reduction in risk observed in normal-weight women was further specific to type I cancers. Conclusions: Long-chain ω-3 intake was associated with reduced endometrial cancer risk only in normal-weight women. Additional studies that use biomarkers of ω-3 intake are needed to more accurately estimate their effects on endometrial cancer risk. This trial was registered at clinicaltrials.gov as NCT00000611. PMID:25739930

  4. Lysophosphatidic Acid Initiates Epithelial to Mesenchymal Transition and Induces β-Catenin-mediated Transcription in Epithelial Ovarian Carcinoma*

    PubMed Central

    Burkhalter, Rebecca J.; Westfall, Suzanne D.; Liu, Yueying; Stack, M. Sharon

    2015-01-01

    During tumor progression, epithelial ovarian cancer (EOC) cells undergo epithelial-to-mesenchymal transition (EMT), which influences metastatic success. Mutation-dependent activation of Wnt/β-catenin signaling has been implicated in gain of mesenchymal phenotype and loss of differentiation in several solid tumors; however, similar mutations are rare in most EOC histotypes. Nevertheless, evidence for activated Wnt/β-catenin signaling in EOC has been reported, and immunohistochemical analysis of human EOC tumors demonstrates nuclear staining in all histotypes. This study addresses the hypothesis that the bioactive lipid lysophosphatidic acid (LPA), prevalent in the EOC microenvironment, functions to regulate EMT in EOC. Our results demonstrate that LPA induces loss of junctional β-catenin, stimulates clustering of β1 integrins, and enhances the conformationally active population of surface β1 integrins. Furthermore, LPA treatment initiates nuclear translocation of β-catenin and transcriptional activation of Wnt/β-catenin target genes resulting in gain of mesenchymal marker expression. Together these data suggest that LPA initiates EMT in ovarian tumors through β1-integrin-dependent activation of Wnt/β-catenin signaling, providing a novel mechanism for mutation-independent activation of this pathway in EOC progression. PMID:26175151

  5. Initiation points for cellular deoxyribonucleic acid replication in human lymphoid cells converted by Epstein-Barr virus

    SciTech Connect

    Oppenheim, A.; Shlomai, Z.; Ben-Bassat, H.

    1981-08-01

    Replicon size was estimated in two Epstein-Barr virus (EBV)-negative human lymphoma lines, BJAB and Ramos, and four EBV-positive lines derived from the former ones by infection (conversion) with two viral strains, B95-8 and P3HR-1. Logarithmic cultures were pulse-labeled with (/sup -3/H)thymidine, and the deoxyribonucleic acid was spread on microscopic slides and autoradiographed by the method of Huberman and Riggs. Three of the four EBV-converted cell lines, BJAB/B95-8, Ra/B95-8, and Ra/HRIK, were found to have significantly shorter replicons (41, 21, 54% shorter, respectively), i.e., more initiation points, than their EBV-negative parents. BJAB/HRIK had replicons which were only slightly shorter (11%) than those of BJAB. However, analysis of track length demonstrated that extensive track fusion occurred during the labeling of BJAB/HRIK, implying that its true average replicon size is shorter than the observed value. The results indicate that in analogy to simian virus 40, EBV activates new initiation points for cellular DNA replication in EBV-transformed cells.

  6. Proton transport by a bacteriorhodopsin mutant, aspartic acid-85-->asparagine, initiated in the unprotonated Schiff base state.

    PubMed Central

    Dickopf, S; Alexiev, U; Krebs, M P; Otto, H; Mollaaghababa, R; Khorana, H G; Heyn, M P

    1995-01-01

    At alkaline pH the bacteriorhodopsin mutant D85N, with aspartic acid-85 replaced by asparagine, is in a yellow form (lambda max approximately 405 nm) with a deprotonated Schiff base. This state resembles the M intermediate of the wild-type photocycle. We used time-resolved methods to show that this yellow form of D85N, which has an initially unprotonated Schiff base and which lacks the proton acceptor Asp-85, transports protons in the same direction as wild type when excited by 400-nm flashes. Photoexcitation leads in several milliseconds to the formation of blue (630 nm) and purple (580 nm) intermediates with a protonated Schiff base, which decay in tens of seconds to the initial state (400 nm). Experiments with pH indicator dyes show that at pH 7, 8, and 9, proton uptake occurs in about 5-10 ms and precedes the slow release (seconds). Photovoltage measurements reveal that the direction of proton movement is from the cytoplasmic to the extracellular side with major components on the millisecond and second time scales. The slowest electrical component could be observed in the presence of azide, which accelerates the return of the blue intermediate to the initial yellow state. Transport thus occurs in two steps. In the first step (milliseconds), the Schiff base is protonated by proton uptake from the cytoplasmic side, thereby forming the blue state. From the pH dependence of the amplitudes of the electrical and photocycle signals, we conclude that this reaction proceeds in a similar way as in wild type--i.e., via the internal proton donor Asp-96. In the second step (seconds) the Schiff base deprotonates, releasing the proton to the extracellular side. PMID:8524795

  7. Improve the Strength of PLA/HA Composite Through the Use of Surface Initiated Polymerization and Phosphonic Acid Coupling Agent

    PubMed Central

    Wang, Tongxin; Chow, Laurence C.; Frukhtbeyn, Stanislav A.; Ting, Andy Hai; Dong, Quanxiao; Yang, Mingshu; Mitchell, James W.

    2011-01-01

    Bioresorbable composite made from degradable polymers, e.g., polylactide (PLA), and bioactive calcium phosphates, e.g., hydroxyapatite (HA), are clinically desirable for bone fixation, repair and tissue engineering because they do not need to be removed by surgery after the bone heals. However, preparation of PLA/HA composite from non-modified HA usually results in mechanical strength reductions due to a weak interface between PLA and HA. In this study, a calcium-phosphate/phosphonate hybrid shell was developed to introduce a greater amount of reactive hydroxyl groups onto the HA particles. Then, PLA was successfully grafted on HA by surface-initiated polymerization through the non-ionic surface hydroxyl groups. Thermogravimetric analysis indiated that the amount of grafted PLA on HA can be up to 7 %, which is about 50 % greater than that from the literature. PLA grafted HA shows significantly different pH dependent ζ-potential and particle size profiles from those of uncoated HA. By combining the phosphonic acid coupling agent and surface initiated polymerization, PLA could directly link to HA through covalent bond so that the interfacial interaction in the PLA/HA composite can be significantly improved. The diametral tensile strength of PLA/HA composite prepared from PLA-grafted HA was found to be over twice that of the composite prepared from the non-modified HA. Moreover, the tensile strength of the improved composite was 23 % higher than that of PLA alone. By varying additional variables, this approach has the potential to produce bioresorbable composites with improved mechanical properties that are in the range of natural bones, and can have wide applications for bone fixation and repair in load-bearing areas. PMID:22399838

  8. A Mechanistic Study of a-Amino Acid-N-Carboxy Anhydride Polymerization: Comparing Initiation and Termination Events in High Vacuum and Traditional Polymerization Techniques

    SciTech Connect

    Pickel, Deanna L; Politakos, Nikolaos; Avgeropoulos, Apostolos; Messman, Jamie M

    2009-01-01

    High-vacuum polymerization of -amino acid-N-carboxyanhydride (NCAs) affords polymers with controlled molecular weights and narrow polydispersities, however a comprehensive study of the end-group composition of the resulting poly(amino acid)s has not yet been performed. This reveals crucial information, as the end-groups are indicative of both the polymerization mechanism (i.e., initiation event) as well as the termination pathways. To this end, poly(O-benzyl-L-tyrosine) initiated by 1,6-diaminohexane was synthesized and subsequently characterized by MALDI-TOF MS, NALDI -TOF MS and 13C NMR spectroscopy to ascertain the end-group structure. Polymers were prepared by both high vacuum and glove box techniques in DMF/THF. Preparation of poly(O-benzyl-L-tyrosine) by high vacuum techniques yielded a polymer initiated exclusively by the normal amine mechanism, and termination by reaction with DMF was observed. In contrast, polymers prepared in the glove box were initiated by the normal amine and activated monomer mechanisms, and several termination products are evident. To our knowledge, this is the first rigorous and comparative analysis of the end-group structure, and it demonstrates the advantage of high vacuum techniques for polymerization of NCAs for the preparation of well-defined poly(amino acid)s with end-group fidelity.

  9. Airway uric acid is a sensor of inhaled protease allergens and initiates type 2 immune responses in respiratory mucosa1

    PubMed Central

    Hara, Kenichiro; Iijima, Koji; Elias, Martha K.; Seno, Satoshi; Tojima, Ichiro; Kobayashi, Takao; Kephart, Gail M.; Kurabayashi, Masahiko; Kita, Hirohito

    2014-01-01

    While type 2 immune responses to environmental antigens are thought to play pivotal roles in asthma and allergic airway diseases, the immunological mechanisms that initiate the responses are largely unknown. Many allergens have biologic activities, including enzymatic activities and abilities to engage innate pattern-recognition receptors such as TLR4. Here we report that IL-33 and thymic stromal lymphopoietin (TSLP) were produced quickly in the lungs of naïve mice exposed to cysteine proteases, such as bromelain and papain, as a model for allergens. IL-33 and TSLP sensitized naïve animals to an innocuous airway antigen OVA, which resulted in production of type 2 cytokines and IgE antibody and eosinophilic airway inflammation when mice were challenged with the same antigen. Importantly, upon exposure to proteases, uric acid (UA) was rapidly released into the airway lumen, and removal of this endogenous UA by uricase prevented type 2 immune responses. UA promoted secretion of IL-33 by airway epithelial cells in vitro, and administration of UA into the airways of naïve animals induced extracellular release of IL-33, followed by both innate and adaptive type 2 immune responses in vivo. Finally, a potent UA synthesis inhibitor, febuxostat, mitigated asthma phenotypes that were caused by repeated exposure to natural airborne allergens. These findings provide mechanistic insights into the development of type 2 immunity to airborne allergens and recognize airway UA as a key player that regulates the process in respiratory mucosa. PMID:24663677

  10. Airway uric acid is a sensor of inhaled protease allergens and initiates type 2 immune responses in respiratory mucosa.

    PubMed

    Hara, Kenichiro; Iijima, Koji; Elias, Martha K; Seno, Satoshi; Tojima, Ichiro; Kobayashi, Takao; Kephart, Gail M; Kurabayashi, Masahiko; Kita, Hirohito

    2014-05-01

    Although type 2 immune responses to environmental Ags are thought to play pivotal roles in asthma and allergic airway diseases, the immunological mechanisms that initiate the responses are largely unknown. Many allergens have biologic activities, including enzymatic activities and abilities to engage innate pattern-recognition receptors such as TLR4. In this article, we report that IL-33 and thymic stromal lymphopoietin were produced quickly in the lungs of naive mice exposed to cysteine proteases, such as bromelain and papain, as a model for allergens. IL-33 and thymic stromal lymphopoietin sensitized naive animals to an innocuous airway Ag OVA, which resulted in production of type 2 cytokines and IgE Ab, and eosinophilic airway inflammation when mice were challenged with the same Ag. Importantly, upon exposure to proteases, uric acid (UA) was rapidly released into the airway lumen, and removal of this endogenous UA by uricase prevented type 2 immune responses. UA promoted secretion of IL-33 by airway epithelial cells in vitro, and administration of UA into the airways of naive animals induced extracellular release of IL-33, followed by both innate and adaptive type 2 immune responses in vivo. Finally, a potent UA synthesis inhibitor, febuxostat, mitigated asthma phenotypes that were caused by repeated exposure to natural airborne allergens. These findings provide mechanistic insights into the development of type 2 immunity to airborne allergens and recognize airway UA as a key player that regulates the process in respiratory mucosa.

  11. A multicenter study of topical azelaic acid 15% gel in combination with oral doxycycline as initial therapy and azelaic acid 15% gel as maintenance monotherapy.

    PubMed

    Thiboutot, Diane M; Fleischer, Alan B; Del Rosso, James Q; Rich, Phoebe

    2009-07-01

    This two-phase, multicenter study was undertaken to examine the safety and efficacy of combination therapy with oral doxycycline and topical azelaic acid (AzA) 15% gel in moderate-to-severe papulopustular rosacea and to determine the effect of subsequent maintenance monotherapy with AzA 15% gel alone. In the initial open-label, non-randomized phase of the study, subjects (n=172) received topical AzA 15% gel and oral doxycycline (100 mg), both twice daily, for < or = 12 weeks. In the second, double-blind study phase, subjects who had initially undergone at least four weeks of combination treatment in phase 1 and who achieved > or = 75% inflammatory lesion count reduction (n=136) were randomized to receive either AzA 15% gel or its vehicle twice daily for an additional 24 weeks. Assessments of efficacy were obtained at four-week intervals throughout both phases of the study and included change in inflammatory lesion count, investigator global assessment (IGA) of rosacea severity, and separate assessments of erythema and telangiectasia severity. At the last visit for each phase of the study, the investigator and participant each rated overall improvement, with the participant rating cosmetic acceptability and the investigator rating treatment as "success" or "failure" based on IGA score. During the second phase of the trial, the rate of relapse -- defined as either a 50% deterioration in the lesion count improvement from phase 1, an increase in erythema intolerable to the subject or maintenance therapy failure as judged by the investigator and/or the subject -- was obtained. Safety assessments were conducted for both phases of the study and included analysis of adverse events (AEs) and a rating of cutaneous tolerability by the subject. By week 12 of the open-label phase of the study, 81.4% of subjects had reached a 75% or greater reduction in inflammatory lesion count, and 64% of patients achieved treatment success. During the second study phase (maintenance phase

  12. Evidence for an initiation of the methanol-to-olefin process by reactive surface methoxy groups on acidic zeolite catalysts.

    PubMed

    Wang, Wei; Buchholz, Andreas; Seiler, Michael; Hunger, Michael

    2003-12-10

    Recent progress reveals that, in the methanol-to-olefin (MTO) process on acidic zeolites, the conversion of an equilibrium mixture of methanol and DME is dominated by a "hydrocarbon pool" mechanism. However, the initial C-C bond formation, that is, the chemistry during the kinetic "induction period" leading to the reactive hydrocarbon pool, still remains unclear. With the application of a stopped-flow protocol, in the present work, pure surface methoxy groups [SiO(CH(3))Al] were prepared on various acidic zeolite catalysts (H-Y, H-ZSM-5, H-SAPO-34) at temperatures lower than 473 K, and the further reaction of these methoxy species was investigated by in situ (13)C MAS NMR spectroscopy. By using toluene and cyclohexane as probe molecules which are possibly involved in the MTO process, we show the high reactivity of surface methoxy species. Most importantly, the formation of hydrocarbons from pure methoxy species alone is demonstrated for the first time. It was found that (i) surface methoxy species react at room temperature with water to methanol, indicating the occurrence of a chemical equilibrium between these species at low temperatures. In the presence of aromatics and alkanes, (ii) the reactivity of surface methoxy groups allows a methylation of these organic compounds at reaction temperatures of ca. 433 and 493 K, respectively. In the absence of water and other organic species, that is, under flow conditions and on partially methylated catalysts, (iii) a conversion of pure methoxy groups alone to hydrocarbons was observed at temperatures of T >/= 523 K. This finding indicates a possible formation of the first hydrocarbons during the kinetic induction period of the MTO process via the conversion of pure surface methoxy species (case iii). After the first hydrocarbons are formed, or in the presence of a small amount of organic impurities, surface methoxy groups contribute to a further methylation of these organic compounds (case ii), leading to the formation of

  13. Equilibrium aluminium hydroxo-oxalate phases during initial clay formation; H +-Al 3+-oxalic acid-Na + system

    NASA Astrophysics Data System (ADS)

    Bilinski, Halka; Horvath, Laszlo; Ingri, Nils; Sjöberg, Staffan

    1986-09-01

    The conditions necessary for initial clay formation have been studied in different model systems comprising different organic acids besides Si and Al. In the present paper the solid phases and the precipitation boundary characterizing the subsystem H +-Al 3+-oxalic acid (H 2L) are discussed. pH and tyndallometric measurements were performed in an ionic medium of 0.6 M Na(Cl) at 25 °C. The two phases Al 3(OH) 7(C 2O 4) · 3H 2O (phase I) and NaAl(OH) 2(C 2O 4) · 3H 2O (phase II) determine the precipitation boundary. The following formation constants for the two phases were deduced: lgβ1 = lg([ Al3+] -3[ H2C2O4] -1[ H+] 9 = -21.87 ± 0.08 and lgβ11 = lg([ Al3+] -1[ H2C2O4] -1[ H+] 4 = -5.61 ± 0.06. Phase I exists in the range [ Al] tot≥ 10 -4.4moldm-3,[ H2C2O4] tot ≥ 10 -4.9moldm-3 and at pH < 6.8, thus being a possible precipitate in oxalic-rich natural waters. The more soluble sodium phase is unlikely to exist in natural waters. The two phases are metastable relative to crystalline gibbsite and may be considered as the first precipitation step in the transition from aqueous Al oxalates down to stable Al hydroxide. Model calculations illustrating these competing hydrolysis-complexation reactions are discussed in terms of predominance and speciation diagrams. The solid phases have been characterized by X-ray analysis of powders, TGA and IR spectra, and tentative structures are proposed. Phase I seems to be an octahedral layer structure, in which 3/5 of the octahedral sites between two close packed oxygen sheets are occupied by Al 3+ and the oxalate ion acts as a bridge ligand between two aluminium atoms. Phase II forms a more open sheet structure and has ion exchange properties. Powder data for a phase crystallized from the studied solution after a year are also presented. This phase, Na 4Al 2(OH) 2(C 2O 4) 4 · 10H 2O, supports the results from the equilibrium analysis of recent solution data by SJöBERG and ÖHMAN (1985), who have found the dinuclear

  14. Particulate matter initiates inflammatory cytokine release by activation of capsaicin and acid receptors in a human bronchial epithelial cell line.

    PubMed

    Veronesi, B; Oortgiesen, M; Carter, J D; Devlin, R B

    1999-01-01

    cells, pretreated with amiloride before ROFA exposure, showed a partial (approximately 25%) reduction of IL-6. Together, these data indicate that the acidic, soluble components of ROFA initiate cytokine release in BEAS-2B cells through activation of both capsaicin- and pH-sensitive irritant receptors. Copyright 1999 Academic Press.

  15. Comparative evaluation of manganese peroxidase- and Mn(III)-initiated peroxidation of C18 unsaturated fatty acids by different methods

    Treesearch

    Alexander N. Kapich; Tatyana V. Korneichik; Kenneth E. Hammel; Annele Hatakka

    2011-01-01

    The peroxidation of C18 unsaturated fatty acids by fungal manganese peroxidase (MnP)/Mn(II) and by chelated Mn(III) was studied with application of three different methods: by monitoring oxygen consumption, by measuring conjugated dienes and by thiobarbituric acid-reactive substances (TBARS) formation. All tested polyunsaturated fatty acids (PUFAs) were oxidized by MnP...

  16. Products of the radical initiated oxidation of model solid and liquid organic acid particles in simulated "clean" and "polluted" environments.

    NASA Astrophysics Data System (ADS)

    Renbaum, L. H.; Smith, G. D.

    2009-05-01

    Using a flow tube reactor coupled to a chemical ionization mass spectrometer, the Cl-initiated oxidation of solid and supercooled liquid organic acid particles were investigated at 293 K. In creating aerosols of species which are able to be supercooled or solid at room temperature, it is possible to distinguish the effect of phase on particle reactivity and product formation. In a clean atmosphere, where there are negligible concentrations of NOx, the primary fate of peroxy radicals (formed from H-abstraction by Cl and OH radicals in the presence of O2) are their reactions to form ketone and alcohol products. These products are then able to undergo further oxidation to form multiply oxidized products. The formation of low-molecular weight volatile species may also be important in the oxidative aging of organic aerosols, however neither the mechanism of their formation nor their formation yields are well understood. We have shown that, for equivalent Cl exposures, more multiply-oxidized species as well as more low-molecular-weight species were created from the oxidation of solid particles than from liquid particles. The findings from these studies suggest that slower diffusion of the oxidation products in solid particles confines them to the surface where they continue to react with Cl radicals producing more-highly- functionalized products which may decompose more readily. By introducing nitric oxide to the flow tube reaction system, we show that in a polluted atmosphere, where NOx is present in significant concentrations, organic nitrate formation may become important on the surface of solid particles but not liquid particles as the RO2 are confined to the surface of solid particles (causing a enhanced localized concentration of RO2) where they may then react with ambient nitric oxide through the reaction RO2 + NO → RO2NO* → RONO2. These experiments of these model systems indicate that particle phase could be important in determining how organic aerosols

  17. Alternating Sequence Controlled Copolymer Synthesis of α-Hydroxy Acids via Syndioselective Ring-Opening Polymerization of O-Carboxyanhydrides Using Zirconium/Hafnium Alkoxide Initiators.

    PubMed

    Sun, Yangyang; Jia, Zhaowei; Chen, Changjuan; Cong, Yong; Mao, Xiaoyang; Wu, Jincai

    2017-08-09

    The ring-opening polymerization (ROP) of O-carboxyanhydrides (OCAs) can give diverse poly(α-hydroxy acid)s (PAHAs) with different functional groups because of easy modification of the side group of OCAs, which can extend applications of PAHAs widely. The stereoselective polymerization of O-carboxyanhydrides and further sequence controlled alternating copolymerization of OCAs were still big challenges until now for lack of suitable catalysts/initiators. In this work, a highly syndioselective ROP of OCAs system as the first stereoselective example in this area is reported using zirconium/hafnium alkoxides as initiators with the highest Pr value up to 0.95. Furthermore, these initiators were successfully applied in the precisely alternating sequence controlled copolymerization of PheOCA and Tyr(Bn)OCA, and alternating copolymerization of LacOCA and PheOCA was also achieved.

  18. Effect of sodium sulfite, carboxylic monomer, and phosphoric acid etching on bonding of tri-n-butylborane initiated resin to human enamel.

    PubMed

    Nogawa, Hiroshi; Koizumi, Hiroyasu; Akazawa, Nobutaka; Hiraba, Haruto; Nakamura, Mitsuo; Matsumura, Hideo

    2015-03-01

    The purpose of the present study is evaluation of bonding durability of tri-n-butylborane (TBB) initiated resin without 4-methacryloyloxyethyl trimellitate anhydride (4-META) joined to human enamel. Ground human enamel was bonded with TBB resin under six surface conditions: 1) as ground, 2) primed with Teeth Primer, 3) sodium sulfite solution, 4) 4-META solution, 5) acetone-water, and 6) phosphoric acid etching. Pre- and post-thermocycling bond strengths and change in strength after thermocycling were compared. Etching enamel with 35-45% phosphoric acid enhanced bonding durability between enamel and TBB-initiated resin. Priming with Teeth Primer or 4-META solution improved bond strength between enamel and TBB-initiated resin. Sodium sulfite had little effect on enamel bonding in the present bonding systems.

  19. Retinoic acid-dependent stimulation of 2,2'-azobis(2-amidinopropane)-initiated autoxidation of linoleic acid in sodium dodecyl sulfate micelles: a novel prooxidant effect of retinoic acid.

    PubMed

    Freyaldenhoven, M A; Lehman, P A; Franz, T J; Lloyd, R V; Samokyszyn, V M

    1998-02-01

    (E)-Retinoic acid (RA) was shown to stimulate the rate of 2,2'-azobis(2-amidinopropane) (AAPH)-initiated autoxidation of linoleic acid (18:2) in sodium dodecyl sulfate (SDS) micelles. RA-dependent stimulation of 18:2 autoxidation was characterized by enhanced rates of dioxygen uptake which were linear with retinoid concentration. In contrast, 5,6-epoxy-RA, a major oxidation product of RA, failed to affect the rate of dioxygen consumption at all concentrations tested. RA was also shown to stimulate peroxyl radical-dependent oxidation of styrene to the corresponding oxirane when styrene was included in the micellar system as a molecular probe. Furthermore, unequivocal evidence of RA-dependent stimulation of 18:2 autoxidation was obtained by relative quantitation of 13-hydroxy-(9Z, 11E)-octadecadienoic acid (13-HODE) plus 9-hydroxy-(10E,12Z)-octadecadienoic acid (9-HODE) production. In addition, enhanced carbon-centered radical formation was demonstrated in the presence of RA by EPR spectroscopy using alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone (4-POBN) as a spin trap. Analysis and quantitation of RA oxidation products indicated that RA was oxidized to one primary product, 5,6-epoxy-RA, which was identified on the basis of cochromatography with synthetic standard (in a reverse-phase HPLC system), electronic absorption spectroscopy, and positive chemical ionization mass spectrometry of the corresponding methyl ester. Other minor oxidation products were also detected but not characterized. In contrast, reaction mixtures devoid of 18:2 failed to demonstrate significant retinoid oxidation. Mechanisms are proposed to account for the prooxidant effects of RA in this system.

  20. Initiation of RNA synthesis in vitro by vesicular stomatitis virus: single internal initiation in the presence of aurintricarboxylic acid and vanadyl ribonucleoside complexes.

    PubMed Central

    Talib, S; Hearst, J E

    1983-01-01

    In the presence of aurintricarboxylic acid (ATA) and vanadyl ribonucleoside complexes (VRC), we have isolated and characterized a small RNA, product of VSV in vitro transcription. This RNA is capped and lacks poly(A) at its 3'-end. Nucleotide sequence analysis revealed that this RNA corresponds to the 5'-terminal transcription product of the N-gene. The termination of the transcription occurs precisely at the 118th base from the 3'-end of the VSV genome. Analysis of the nucleotide sequence around this region reveals a potential secondary structure. Photoreaction of the VSV with 4'-substituted psoralen fails to inhibit the synthesis of the 68-mer RNA under conditions where full length mRNA synthesis is blocked, indicating that the psoralen binding site is located further into the N-gene. Since this RNA is the only in vitro transcription product synthesized under these conditions, the existence of two types of polymerase activities, one for the synthesis of leader RNA and one for mRNA, is suggested. Images PMID:6314272

  1. Initial characterization of carbon flows through microbial communities in Beowulf spring, an acidic hot spring in Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Kreuzer, H.; Moran, J.; Ehrhardt, C.; Melville, A.; Kranz, A.; Inskeep, W. P.

    2011-12-01

    Beowulf Springs are acidic, sulfidic hot springs in Yellowstone National Park. Visual inspection of the springs reveals distinct geochemical regions starting with a sulfur deposition zone followed by a transition to iron oxide deposition downstream. The relatively rapid sulfur and iron oxide deposition rates in this spring suggests the processes are microbially mediated (since, for instance, abiotic iron oxidation is kinetically slow at this temperature and pH) and previous diversity studies identify microbial communities consistent with the observed metabolic products (namely sulfur and iron oxide). While the energetics of sulfide and iron oxidation are sufficient for supporting microbial activity, a suitable carbon source remains undocumented. The temperatures in Beowulf approach 80 °C, which is above the photosynthetic upper temperature limit thus precluding photosynthetic-based autotrophy within the spring itself. Observed potential carbon sources in Beowulf include dissolved inorganic carbon, dissolved organic carbon, and methane. We are employing geochemical and stable isotope techniques to assess carbon inventories in the system. With thorough analysis we hope to identify both the major carbon stores in the system and track how they are transferred between microbial components in Beowulf. Initial stable isotope measurements focused on bulk isotope analysis of major carbon pools; both directly in the spring and in surrounding areas that may affect the spring water through runoff or ground water migration. We are analyzing bulk carbon isotopes of different microbial groups in the spring, the dissolved organic and inorganic carbon in the spring, and surrounding soils and potential plant inputs. Isotopic similarity between dissolved organic carbon and soil organic carbon is consistent with a common carbon source (local vegetation) but has not yet been confirmed as such. Correlation between δ13C of microbial biomass and dissolved organic carbon are suggestive

  2. Slow recovery of the fatty acid composition of sciatic nerve in rats fed a diet initially low in n-3 fatty acids.

    PubMed

    Bourre, J M; Youyou, A; Durand, G; Pascal, G

    1987-07-01

    The sciatic nerve of rats fed sunflower oil (6 mg 18:3-n-3/100 g of diet) presented dramatic alterations in the long chain polyunsaturated fatty acids in comparison with those fed soy oil (130 mg 18:3n-3/100 g of diet). In both 15-day-old and 60-day-old animals fed sunflower oil, 22:6n-3 (cervonic acid) was four-fold less, 22:5n-6 was 10-fold greater; adrenic acid (22:4n-6) was slightly greater and arachidonic acid (20:4n-6) was close to that in rats fed soy oil. The percentage distribution of total polyunsaturated fatty acids as well as the individual saturated and monounsaturated fatty acids were the same in both groups. When the sunflower oil-fed animals were switched to a soy oil-containing diet for either 15 or 60 days, the percentage distribution of 22:6n-3 increased slowly to reach the control value 2.5 months later. Conversely 22:5n-6 decreased slowly. The decay of 22:5n-6 was more rapid than the increase of 22:6n-3.

  3. Electron paramagnetic resonance study of hydrogen peroxide/ascorbic acid ratio as initiator redox pair in the inulin-gallic acid molecular grafting reaction.

    PubMed

    Arizmendi-Cotero, Daniel; Gómez-Espinosa, Rosa María; Dublán García, Octavio; Gómez-Vidales, Virginia; Dominguez-Lopez, Aurelio

    2016-01-20

    Gallic acid (GA) was grafted onto inulin using the free radicals method, generated by the hydrogen peroxide/ascorbic acid (H2O2/AA) redox pair. Molar ratios of H2O2/AA at 9, 20, 39 and 49 were evaluated by Electron Paramagnetic Resonance in order to find the effect of the oxidation of the inulin and the efficiency in the inulin-gallic acid grafting (IGA). The highest concentration of the inulin macro-radical was obtained with H2O2/AA molar ratios of 20 and 49 with the removal of a hydrogen atom from a methyl group of the inulin fructose monomers. The highest grafting ratio (30.4 mg GA eq/g IGA) was obtained at 9 M of H2O2/AA. UV-Vis, FT-IR-ATR and XDR results confirmed a successful IGA grafting. The efficiency of the grafting reaction depends on the concentration of the macro-radical, it depends on the molar ratio of H2O2/AA, being affected by simultaneous reactions between components of the mixture (H2O2, AA, inulin, GA and eventually atmospheric oxygen) as well. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Hydrogen-bonded clusters of 1, 1'-ferrocenedicarboxylic acid on Au(111) are initially formed in solution.

    PubMed

    Quardokus, Rebecca C; Wasio, Natalie A; Brown, Ryan D; Christie, John A; Henderson, Kenneth W; Forrest, Ryan P; Lent, Craig S; Corcelli, Steven A; Kandel, S Alex

    2015-03-14

    Low-temperature scanning tunneling microscopy is used to observe self-assembled structures of ferrocenedicarboxylic acid (Fc(COOH)2) on the Au(111) surface. The surface is prepared by pulse-deposition of Fc(COOH)2 dissolved in methanol, and the solvent is evaporated before imaging. While the rows of hydrogen-bonded dimers that are common for carboxylic acid species are observed, the majority of adsorbed Fc(COOH)2 is instead found in six-molecule clusters with a well-defined and chiral geometry. The coverage and distribution of these clusters are consistent with a random sequential adsorption model, showing that solution-phase species are determinative of adsorbate distribution for this system under these reaction conditions.

  5. A single amino acid change in a geminiviral Rep protein differentiates between triggering a plant defence response and initiating viral DNA replication.

    PubMed

    Jin, Mingfei; Li, Chunyang; Shi, Yan; Ryabov, Eugene; Huang, Jing; Wu, Zirong; Fan, Zaifeng; Hong, Yiguo

    2008-10-01

    We have devised an in planta system for functional analysis of the replication-associated protein (Rep) of African cassava mosaic virus (ACMV). Using this assay and PCR-based random mutagenesis, we have identified an ACMV Rep mutant that failed to trigger the hypersensitive response (HR), but had an enhanced ability to initiate DNA replication. The mutant Rep-green fluorescent protein (GFP) fusion protein was localized to the nucleus. Sequence analysis showed that the mutated Rep gene had three nucleotide changes (A6-->T, T375-->G and G852-->A); only the A6-->T transversion resulted in an amino acid substitution (Arg to Ser), which is at the second residue in the 358 amino acid ACMV Rep protein. Our results indicate that a single amino acid can alter the differential ability of ACMV Rep to trigger the host-mediated HR defence mechanism and to initiate viral DNA replication. The implications of this finding are discussed in the context of plant-virus interactions.

  6. Dietary long-chain fatty acids and carbohydrate biomarker evaluation in a controlled feeding study in participants from the Women's Health Initiative cohort.

    PubMed

    Song, Xiaoling; Huang, Ying; Neuhouser, Marian L; Tinker, Lesley F; Vitolins, Mara Z; Prentice, Ross L; Lampe, Johanna W

    2017-06-01

    Background: Biomarkers of macronutrient intake are lacking. Controlled human feeding studies that preserve the normal variation in nutrient and food consumption are necessary for the development and validation of robust nutritional biomarkers.Objective: We aimed to assess the utility of serum phospholipid fatty acids (PLFAs) as biomarkers of dietary intakes of fatty acids, total fat, and carbohydrate.Design: We used an individualized controlled feeding study in which 153 postmenopausal women from the Women's Health Initiative (WHI) were provided with a 2-wk controlled diet that mimicked each individual's habitual food intake. A total of 41 PLFAs were measured with the use of gas chromatography in end-of-feeding-period fasting serum samples and expressed in both relative and absolute concentrations. R(2) values (percentages of variation explained) from linear regressions of (ln-transformed) consumed fatty acids (individual, groups, and broad categories) on (ln-transformed) corresponding measures of serum PLFAs alone and together with selected participant-related variables (age, race/ethnicity, body mass index, season of study participation, education level, and estimated energy intake from doubly labeled water) were used for evaluation against established urinary recovery biomarkers of energy and protein intake as benchmarks. Models to predict intakes of other nutrients were also explored.Results: Intakes of eicosapentaenoic acid and docosahexaenoic acid achieved the benchmark of R(2) > 36% with or without covariates. When all 41 serum PLFAs and participant-related covariates were initially included in the model for selection, cross-validated R(2) achieved >36% for consumed total carbohydrate (grams per day), total saturated fatty acids (SFAs), percentage of energy from SFAs, and total trans fatty acids with serum PLFAs in both relative and absolute concentrations.Conclusions: Serum PLFA biomarkers perform similarly to established energy and protein urinary recovery

  7. Tuning of Recombinant Protein Expression in Escherichia coli by Manipulating Transcription, Translation Initiation Rates, and Incorporation of Noncanonical Amino Acids.

    PubMed

    Schlesinger, Orr; Chemla, Yonatan; Heltberg, Mathias; Ozer, Eden; Marshall, Ryan; Noireaux, Vincent; Jensen, Mogens Høgh; Alfonta, Lital

    2017-06-16

    Protein synthesis in cells has been thoroughly investigated and characterized over the past 60 years. However, some fundamental issues remain unresolved, including the reasons for genetic code redundancy and codon bias. In this study, we changed the kinetics of the Eschrichia coli transcription and translation processes by mutating the promoter and ribosome binding domains and by using genetic code expansion. The results expose a counterintuitive phenomenon, whereby an increase in the initiation rates of transcription and translation lead to a decrease in protein expression. This effect can be rescued by introducing slow translating codons into the beginning of the gene, by shortening gene length or by reducing initiation rates. On the basis of the results, we developed a biophysical model, which suggests that the density of co-transcriptional-translation plays a role in bacterial protein synthesis. These findings indicate how cells use codon bias to tune translation speed and protein synthesis.

  8. Chronic improvement of amino acid nutrition stimulates initiation of global messenger ribonucleic acid translation in tissues of sheep without affecting protein elongation.

    PubMed

    Connors, M T; Poppi, D P; Cant, J P

    2010-02-01

    Initiation of mRNA translation and elongation of the polypeptide chain are 2 regulated processes responsible for the short-term postprandial acceleration of protein synthesis in animal tissues. It is known that a chronic increase in the absorptive supply of AA stimulates protein synthesis in ruminant animals, but effects on translation initiation and elongation are unknown. To determine whether initiation or elongation phases of global mRNA translation are affected by chronic elevation of AA supply, 24 ewe lambs of 25.9 +/- 2.5 kg of BW were randomly allocated to 4 treatment groups of 6 lambs each. All lambs received a basal diet of barley and hay at 1.2 times maintenance ME intake. Treatments were an intravenous (i.v.) saline infusion as a control, i.v. infusion of 6 essential AA (EAA; Arg, Lys, His, Thr, Met, Cys) for 10 d, i.v. infusion of the same EAA excluding Met and Cys (EAA-SAA) for 10 d, and an oral drench of fishmeal twice daily for 17 d. Fishmeal supplementation supplied an extra 719 mg of N x kg(-0.75) x d(-1) and N retention was increased 519 mg x kg(-0.75) x d(-1) over the control. The EAA treatment supplied an extra 343 mg of N x kg(-0.75) x d(-1) directly into the blood, and N balance was increased by 268 mg x kg(-0.75) x d(-1). Deletion of Met plus Cys from EAA had no effect on N balance. The results indicate that Met plus Cys did not limit body protein gain on the basal diet alone or the basal diet plus 6 AA. Protein fractional synthesis rates in liver, duodenum, skin, rumen, semimembranosus, and LM were measured by a flooding dose procedure using L-[ring-2,6-(3)H]-Phe. Ribosome transit times were estimated from the ratio of nascent to total protein-bound radioactivities. Fishmeal and EAA treatments had no effect on RNA, DNA, or protein contents of tissues, but fractional synthesis rate, translational efficiency, and concentrations of active ribosomes were consistently elevated. Ribosome transit time was not affected by long-term AA supply. We

  9. Diel cycling of zinc in a stream impacted by acid rock drainage: Initial results from a new in situ Zn analyzer

    USGS Publications Warehouse

    Chapin, T.P.; Nimick, D.A.; Gammons, C.H.; Wanty, R.B.

    2007-01-01

    Recent work has demonstrated that many trace metals undergo dramatic diel (24-h) cycles in near neutral pH streams with metal concentrations reproducibly changing up to 500% during the diel period (Nimick et al., 2003). To examine diel zinc cycles in streams affected by acid rock drainage, we have developed a novel instrument, the Zn-DigiScan, to continuously monitor in situ zinc concentrations in near real-time. Initial results from a 3-day deployment at Fisher Creek, Montana have demonstrated the ability of the Zn-DigiScan to record diel Zn cycling at levels below 100 ??g/l. Longer deployments of this instrument could be used to examine the effects of episodic events such as rainstorms and snowmelt pulses on zinc loading in streams affected by acid rock drainage. ?? Springer Science+Business Media B.V. 2006.

  10. The role of the U.S. Clean Coal Technology Program in implementing the objectives of the joint Canada-U.S. acid rain mitigation initiative

    SciTech Connect

    Baldwin, A.L.; Smith, D.N.; Mann, A.W.; McIlvried, H.G.; Russell, D.L. Sr.

    1997-12-31

    The Clean Coal Technology (CCT) Program was initiated by the US Department of Energy (DOE) in part as a response to the 1986 Joint Report of the US and Canadian Special Envoys on Acid Rain, with a particular focus on coal-burning electric power plants. The fist three solicitations of the CCT Program were aimed primarily at mitigating the potential impacts of acid rain. Subsequently, the Clean Air Act Amendments of 1990 established emission reduction targets for SO{sub 2} and No{sub x}, which influenced the goals of the last two CCT Program. This paper provides an overview of the CCT Program and reports the significant results, with emphasis on emissions reduction as well as their impact on ozone formation.

  11. Early Changes in Cytochrome P450s and Their Associated Arachidonic Acid Metabolites Play a Crucial Role in the Initiation of Cardiac Hypertrophy Induced by Isoproterenol.

    PubMed

    Althurwi, Hassan N; Maayah, Zaid H; Elshenawy, Osama H; El-Kadi, Ayman O S

    2015-08-01

    Cytochrome P450 enzymes (P450s), along with their cardioprotective metabolites the epoxyeicosatrienoic acids (EETs) and cardiotoxic metabolite 20-hydroxyeicosatetraeonic acid (20-HETE), were found to be altered in cardiac hypertrophy; however, it is unclear whether these changes are causal or epiphenomenon. Therefore, we hypothesized that P450s and their metabolites play a crucial role in the initiation of cardiac hypertrophy. To test our hypothesis, rats and RL-14 cells were treated with the hypertrophic agonist isoproterenol for different time periods. Thereafter, in vivo heart function and wall thickness were assessed using echocardiography. Moreover, the role of P450 epoxygenases, ω-hydroxylases, and soluble epoxide hydrolase (sEH) were determined at mRNA, protein, and activity levels using real-time polymerase chain reaction, Western blot, and liquid chromatography-mass spectrometry, respectively. Our results show that in vivo and in vitro hypertrophy was initiated after 72 hours and 6 hours of isoproterenol treatment, respectively. Studies performed at the prehypertrophy phase showed a significant decrease in P450 epoxygenases along with a significant induction of sEH activity. Consequently, lower EET and higher dihydroxyeicosatrienoic acid levels were observed during this phase. However, significant increases in P450 ω-hydroxylase along with its associated metabolite, 20-HETE, were detected only in vivo. Interestingly, increasing EET levels by P450 epoxygenase induction, sEH inhibition, or exogenous administration of EET prevented the initiation of cardiac hypertrophy through a nuclear factor-κB-mediated mechanism. Taken together, these findings reveal a crucial role of P450 epoxygenases and EETs in the development of cardiac hypertrophy, which could uncover novel targets for prevention of heart failure at early stages. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  12. Correcting the effects of -20 °C storage and aliquot size on erythrocyte fatty acid content in the Women's Health Initiative.

    PubMed

    Pottala, James V; Espeland, Mark A; Polreis, Jason; Robinson, Jennifer; Harris, William S

    2012-09-01

    Red blood cell (RBC) fatty acid (FA) patterns have been shown to predict risk for cardiovascular and other chronic diseases. As part of a project analyzing RBC samples from the Women's Health Initiative Memory Study (WHIMS) we observed implausibly low levels of highly unsaturated fatty acids (HUFA) suggestive of degradation. This was hypothesized to be due to short term storage (<1 month) at -20 °C during sample aliquoting. The purpose of this study was to measure the extent of degradation that occurs under these conditions, and then to use regression calibration equations with multiple imputations to correct the biases. Samples from the Women's Health Initiative that had always been stored at -80 °C were obtained and subjected to similar conditions as the WHIMS samples. General linear mixed models were used to develop bias-corrected calibration equations for each fatty acid. Sample degradation occurred at -20 °C with the average HUFA loss of 3.5 to 5.9 % per week depending on aliquot size (250 and 80 µL, respectively). Using the ratio of HUFA to saturated fatty acids (HUFA/SAT) as a marker of degradation, this bias-correction method raised the HUFA/SAT from 0.70 to 0.81, which was similar to that (0.78) seen in another large study with optimal processing. In summary, RBC samples should always be stored at -80 °C. The FA compositions of the degraded RBC samples from WHIMS were rehabilitated by application of regression calibration equations and multiple imputations, and these imputed datasets should be used in all future WHIMS studies.

  13. Infrared spectroscopic evidence for the initial step of dissociation of the stable benzoic acid cyclic dimer with microsolvation by a single water molecule

    NASA Astrophysics Data System (ADS)

    Katada, Marusu; Fujii, Asuka

    2017-09-01

    The hydrogen-bonded structure of the (Benzoic acid)2-(Water)1 (BA2-W1) cluster was investigated by infrared spectroscopy in the OH stretch region. The stable BA dimer has the cyclic structure with the two hydrogen bonds between the carboxyl groups. The observed infrared spectrum of BA2-W1 shows that the water molecule is inserted in between the two carboxylic groups of the cyclic dimer. This means that a single water molecule begins to dissociate the cyclic dimer. This observation can be regarded as the initial step of dissociation of the stable cyclic BA dimer in aqueous solution.

  14. No activation of new initiation points for deoxyribonucleic acid replication in BALB/c 3T3 cells transformed by Kirsten sarcoma virus

    SciTech Connect

    Oppenheim, A.; Horowitz, A.T.

    1981-08-01

    BALB/c 3T3 cells were transformed by Kirsten sarcoma virus, and five clones were isolated in soft agar. Average replicon sizes of the transformed cell lines were stimated by the method of fiber-autoradiography and found to be the same size as the nontransformed 3T3 cells, analyzed in parallel. The results indicate that, unlike simian virus 40 and Epstein-Barr virus, Kirsten sarcoma virus does not activate new initiation points for cellular deoxyribonucleic acid replication in murine sarcome virus-transformed BALB/c 3T3 cells.

  15. The importance of phase in the radical-initiated oxidation of model organic aerosols: reactions of solid and liquid brassidic acid particles.

    PubMed

    Renbaum, Lindsay H; Smith, Geoffrey D

    2009-04-14

    Using a flow tube reactor coupled to a chemical ionization mass spectrometer, the Cl-initiated oxidation of solid and supercooled liquid brassidic acid (BA, trans-13-docosenoic acid) particles was investigated at 293 K. For the first time radical-initiated oxidation reactions of liquid and solid organic particles of identical chemical composition were performed making it possible to probe the effect of phase. Despite the fact that solubility and/or diffusion in the solid particles is expected to be reduced dramatically, it was observed that the BA in those particles still reacted at 70% of the rate in liquid droplets. The lack of significant slowing upon solidification suggests that the surface is continuously renewed, perhaps by evaporation of volatile products or mixing of underlying solid BA at a surface melt layer. The initial oxidation products were found to be the keto-acid and the alcohol-acid for both solid and liquid, and they account for as much as two thirds of the reacted BA. The distribution of other products, however, was found to be quite different in the two phases. For equivalent Cl concentrations and reaction times more multiply-oxidized species as well as low-molecular-weight species were created from the oxidation of solid particles. Furthermore, the mean mobility diameter of both liquid and solid particles, as determined from a scanning mobility particle sizer, decreased after reaction with larger decreases for the solid particles. These observations are consistent with a loss of mass through evaporation of small, volatile oxidation products. The findings from this study suggest that slower diffusion of the oxidation products in solid particles confines them to the surface where they continue to react with Cl radicals producing more-highly-functionalized products which may decompose more readily. Thus, the solid particles react nearly as efficiently as the liquid ones, but the manner in which they "age" chemically is substantially different

  16. Intronic elements in the Na+/I- symporter gene (NIS) interact with retinoic acid receptors and mediate initiation of transcription

    PubMed Central

    Alotaibi, Hani; Yaman, Elif; Salvatore, Domenico; Di Dato, Valeria; Telkoparan, Pelin; Di Lauro, Roberto; Tazebay, Uygar H.

    2010-01-01

    Activity of the sodium/iodide symporter (NIS) in lactating breast is essential for iodide (I–) accumulation in milk. Significant NIS upregulation was also reported in breast cancer, indicating a potential use of radioiodide treatment. All-trans-retinoic acid (tRA) is a potent ligand that enhances NIS expression in a subset of breast cancer cell lines and in experimental breast cancer models. Indirect tRA stimulation of NIS in breast cancer cells is very well documented; however, direct upregulation by tRA-activated nuclear receptors has not been identified yet. Aiming to uncover cis-acting elements directly regulating NIS expression, we screened evolutionary-conserved non-coding genomic sequences for responsiveness to tRA in MCF-7. Here, we report that a potent enhancer in the first intron of NIS mediates direct regulation by tRA-stimulated nuclear receptors. In vitro as well as in vivo DNA–protein interaction assays revealed direct association between retinoic acid receptor-α (RARα) and retinoid-X-receptor (RXR) with this enhancer. Moreover, using chromatin immunoprecipitation (ChIP) we uncovered early events of NIS transcription in response to tRA, which require the interaction of several novel intronic tRA responsive elements. These findings indicate a complex interplay between nuclear receptors, RNA Pol-II and multiple intronic RAREs in NIS gene, and they establish a novel mechanistic model for tRA-induced gene transcription. PMID:20123735

  17. Intronic elements in the Na+/I- symporter gene (NIS) interact with retinoic acid receptors and mediate initiation of transcription.

    PubMed

    Alotaibi, Hani; Yaman, Elif; Salvatore, Domenico; Di Dato, Valeria; Telkoparan, Pelin; Di Lauro, Roberto; Tazebay, Uygar H

    2010-06-01

    Activity of the sodium/iodide symporter (NIS) in lactating breast is essential for iodide (I(-)) accumulation in milk. Significant NIS upregulation was also reported in breast cancer, indicating a potential use of radioiodide treatment. All-trans-retinoic acid (tRA) is a potent ligand that enhances NIS expression in a subset of breast cancer cell lines and in experimental breast cancer models. Indirect tRA stimulation of NIS in breast cancer cells is very well documented; however, direct upregulation by tRA-activated nuclear receptors has not been identified yet. Aiming to uncover cis-acting elements directly regulating NIS expression, we screened evolutionary-conserved non-coding genomic sequences for responsiveness to tRA in MCF-7. Here, we report that a potent enhancer in the first intron of NIS mediates direct regulation by tRA-stimulated nuclear receptors. In vitro as well as in vivo DNA-protein interaction assays revealed direct association between retinoic acid receptor-alpha (RARalpha) and retinoid-X-receptor (RXR) with this enhancer. Moreover, using chromatin immunoprecipitation (ChIP) we uncovered early events of NIS transcription in response to tRA, which require the interaction of several novel intronic tRA responsive elements. These findings indicate a complex interplay between nuclear receptors, RNA Pol-II and multiple intronic RAREs in NIS gene, and they establish a novel mechanistic model for tRA-induced gene transcription.

  18. Low concentration of ethylenediaminetetraacetic acid (EDTA) affects biofilm formation of Listeria monocytogenes by inhibiting its initial adherence.

    PubMed

    Chang, Yuhua; Gu, Weimin; McLandsborough, Lynne

    2012-02-01

    The distribution and survival of the food-borne pathogen Listeria monocytogenes is associated with its biofilm formation ability, which is affected by various environmental factors. Here we present the first evidence that EDTA at low concentration levels inhibits the biofilm formation of L. monocytogenes. This effect of EDTA is not caused by a general growth inhibition, as 0.1 mM EDTA efficiently reduced the biofilm formation of L. monocytogenes without affecting the planktonic growth. Adding 0.1 mM of EDTA at the starting time of biofilm formation had the strongest biofilm inhibitory effect, while the addition of EDTA after 8 h had no biofilm inhibitory effects. EDTA was shown to inhibit cell-to-surface interactions and cell-to-cell interactions, which at least partially contributed to the repressed initial adherence. The addition of sufficient amounts of cations to saturate EDTA did not restore the biofilm formation, indicating the biofilm inhibition was not due to the chelating properties of EDTA. The study suggests that EDTA functions in the early stage of biofilm process by affecting the initial adherence of L. monocytogenes cells onto abiotic surfaces.

  19. A single amino acid alteration in the initiation protein is responsible for the DNA overproduction phenotype of copy number mutants of plasmid R6K.

    PubMed Central

    Inuzuka, M; Wada, Y

    1985-01-01

    A novel type of high copy-number (cop) mutants of a mini-R6K plasmid were isolated. The mutations were mapped in the pir gene which encodes the pi initiation protein for plasmid R6K DNA replication. They resulted in an alteration by substitution of a single amino acid: threonine to isoleucine at the 108th position for the cop41, and proline to serine at the 113th position for the cop50, of the 305 amino acid pi protein. The cop41 mutation in the pi protein was found to be trans-dominant over the wild-type allele in the copy control of plasmid R6K. Moreover, it was shown that the altered pi protein was not overproduced in maxicells carrying this mutant plasmid and had a higher affinity to the repeated sequence which is present in the pir promoter region. Most likely the mutated pi protein also interacts more efficiently with the same repeated sequences, a target of pi, in the replication origin region and increases the frequency of the initiation event per cell division. Images Fig. 2. Fig. 5. PMID:3000771

  20. Corticotropin-releasing hormone expression in patients with intrahepatic cholestasis of pregnancy after ursodeoxycholic acid treatment: an initial experience.

    PubMed

    Zhou, Fan; Zhang, Li; He, Mao Mao; Liu, Zheng Fei; Gao, Bing Xin; Wang, Xiao Dong

    2014-08-01

    Corticotropin-releasing hormone (CRH) is one of the most potent vasodilatory factors in the human feto-placental circulation. The expression of CRH was significantly down-regulated in patients with intrahepatic cholestasis of pregnancy (ICP). One hundred pregnant women diagnosed with ICP at 34-34(+6) weeks of gestation agreed to participate in this prospective nested case-control study. Thirty ICP patients were finally recruited in this study, with 16 cases in the ursodeoxycholic acid (UDCA) group (UDCA 750 mg/d) and 14 cases in the control group (Transmetil 1000 mg/d or Essentiale 1368 mg/d). Maternal serum samples were obtained in diagnosis and at 37-37(+6) weeks of gestation. Placental tissues were obtained from participants after delivery. ELISA, enzymatic colorimetric and Western blotting were used to evaluate the concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bile acid (TBA) and CRH in maternal serum and expression of CRH in placenta tissues. The UDCA group had greater reduction in maternal serum ALT, AST and TBA levels in ICP patients (all p < 0.01). Maternal serum CRH concentrations in the UDCA group after treatment (122.10 ± 44.20) pg/ml was significantly higher than pretreatment (95.45 ± 26.47) pg/ml (p < 0.01). After treatment, maternal serum CRH concentrations of the UDCA group (122.10 ± 44.20) pg/ml was significantly higher than in the control group (80.71 ± 41.10) pg/ml (p < 0.01). Placental CRH expression in the UDCA group (2.79 ± 1.72) was significantly higher than in the control group (0.69 ± 0.36) (p < 0.01). Maternal serum and placental CRH expression in ICP patients were up-regulated after treatment of UDCA. The up-regulation of CRH expression after UDCA treatment may play an important role in the therapeutic mechanism of ICP. All patients recruited in this study had severe cholestasis (TBA ≥ 40 µmol/L). Further studies are warranted in

  1. Unusual structural evolution of poly(lactic acid) upon annealing in the presence of an initially oriented mesophase.

    PubMed

    Wang, Yaming; Li, Ming; Wang, Kaojin; Shao, Chunguang; Li, Qian; Shen, Changyu

    2014-03-14

    Uniaxial deformations of amorphous poly(lactic acid) (PLA) films were performed at two different temperatures, 70 and 80 °C, at various draw strains. The samples deformed at 70 °C showed a strain-induced mesophase, and the structural ordering and thermal stability increased as the draw strain increased. Further annealing was performed in situ at constant length at the drawing temperature of 70 °C for the films drawn to strains of 100% and 230%. Unusually, we found that after annealing, the crystal structure of the film at lower strain was more ordered than the one at higher strain. Further investigations revealed that upon annealing the structural evolution followed a distinct molecular mechanism for the samples stretched to the two draw strains. For the sample drawn to 100%, the mesophase melted very quickly upon annealing, resulting in chain randomization and the release of the constraints on the thermodynamic relaxation of the oriented amorphous chains. The chain relaxation motions had a beneficial effect on the occurrence of the conformational rearrangements that are necessary for crystalline ordering. By contrast, for the 230% sample, the melting of the mesophase was slow and most of the chain orientations were preserved upon annealing. As a result, a less ordered crystal structure was formed since the local relaxation motions that are necessary for promoting crystalline order via conformational rearrangements were hindered.

  2. Chronic Carbamazepine Administration Attenuates Dopamine D2-like Receptor-Initiated Signaling via Arachidonic Acid in Rat Brain

    PubMed Central

    Chang, Lisa; Chen, Mei; Bell, Jane M.; Rapoport, Stanley I.

    2016-01-01

    Observations that dopaminergic antagonists are beneficial in bipolar disorder and that dopaminergic agonists can produce mania suggest that bipolar disorder involves excessive dopaminergic transmission. Thus, mood stabilizers used to treat the disease might act in part by downregulating dopaminergic transmission. In agreement, we reported that dopamine D2-like receptor mediated signaling involving arachidonic acid (AA, 20:4n-6) was downregulated in rats chronically treated with lithium. To see whether chronic carbamazepine, another mood stabilizer, did this as well, we injected i.p. saline or the D2-like receptor agonist, quinpirole (1 mg/kg), into unanesthetized rats that had been pretreated for 30 days with i.p. carbamazepine (25 mg/kg/day) or vehicle, and used quantitative autoradiography to measure regional brain incorporation coefficients (k*) for AA, markers of signaling. We also measured brain prostaglandin E2 (PGE2), an AA metabolite. In vehicle-treated rats, quinpirole compared with saline significantly increased k* for AA in 35 of 82 brain regions examined, as well as brain PGE2 concentration. Affected regions belong to dopaminergic circuits and have high D2-like receptor densities. Chronic carbamazepine pretreatment prevented the quinpirole-induced increments in k* and in PGE2. These findings are consistent with the hypothesis that effective mood stabilizers generally downregulate brain AA signaling via D2-like receptors, and that this signaling is upregulated in bipolar disorder. PMID:18302021

  3. Fatty acid fouling of forward osmosis membrane: Effects of pH, calcium, membrane orientation, initial permeate flux and foulant composition.

    PubMed

    Zhao, Pin; Gao, Baoyu; Yue, Qinyan; Liu, Pan; Shon, Ho Kyong

    2016-08-01

    Octanoic acid (OA) was selected to represent fatty acids in effluent organic matter (EOM). The effects of feed solution (FS) properties, membrane orientation and initial permeate flux on OA fouling in forward osmosis (FO) were investigated. The undissociated OA formed a cake layer quickly and caused the water flux to decline significantly in the initial 0.5hr at unadjusted pH3.56; while the fully dissociated OA behaved as an anionic surfactant and promoted the water permeation at an elevated pH of 9.00. Moreover, except at the initial stage, the sudden decline of water flux (meaning the occurrence of severe membrane fouling) occurred in two conditions: 1. 0.5mmol/L Ca(2+), active layer facing draw solution (AL-DS) and 1.5mol/L NaCl (DS); 2. No Ca(2+), active layer-facing FS (AL-FS) and 4mol/L NaCl (DS). This demonstrated that cake layer compaction or pore blocking occurred only when enough foulants were absorbed into the membrane surface, and the water permeation was high enough to compact the deposit inside the porous substrate. Furthermore, bovine serum albumin (BSA) was selected as a co-foulant. The water flux of both co-foulants was between the fluxes obtained separately for the two foulants at pH3.56, and larger than the two values at pH9.00. This manifested that, at pH3.56, BSA alleviated the effect of the cake layer caused by OA, and OA enhanced BSA fouling simultaneously; while at pH9.00, the mutual effects of OA and BSA eased the membrane fouling. Copyright © 2016. Published by Elsevier B.V.

  4. Shape-Persistent, Thermoresponsive Polypeptide Brushes Prepared by Vapor Deposition Surface-Initiated Ring-Opening Polymerization of α-Amino Acid N -Carboxyanhydrides

    SciTech Connect

    Shen, Yong; Desseaux, Solenne; Aden, Bethany; Lokitz, Bradley S.; Kilbey, S. Michael; Li, Zhibo; Klok, Harm-Anton

    2015-04-20

    We report that surface-grafting thermoresponsive polymers allows the preparation of thin polymer brush coatings with surface properties that can be manipulated by variation of temperature. In most instances, thermoresponsive polymer brushes are produced using polymers that dehydrate and collapse above a certain temperature. This report presents the preparation and properties of polymer brushes that show thermoresponsive surface properties, yet are shape-persistent in that they do not undergo main chain collapse. The polymer brushes presented here are obtained via vapor deposition surface-initiated ring-opening polymerization (SI-ROP) of γ-di- or tri(ethylene glycol)-modified glutamic acid N-carboxyanhydrides. Vapor deposition SI-ROP of γ-di- or tri(ethylene glycol)-modified L- or D-glutamic acid N-carboxyanhydrides affords helical surface-tethered polymer chains that do not show any changes in secondary structure between 10 and 70 °C. QCM-D experiments, however, revealed significant dehydration of poly(γ-(2-(2-methoxyethoxy)ethyl)-l-glutamate) (poly(L-EG2-Glu)) brushes upon heating from 10 to 40 °C. At the same time, AFM and ellipsometry studies did not reveal significant variations in film thickness over this temperature range, which is consistent with the shape-persistent nature of these polypeptide brushes and indicates that the thermoresponsiveness of the films is primarily due to hydration and dehydration of the oligo(ethylene glycol) side chains. The results we present here illustrate the potential of surface-initiated NCA ring-opening polymerization to generate densely grafted assemblies of polymer chains that possess well-defined secondary structures and tunable surface properties. These polypeptide brushes complement their conformationally unordered counterparts that can be generated via surface-initiated polymerization of vinyl-type monomers and represent another step forward to biomimetic surfaces and interfaces.

  5. Shape-Persistent, Thermoresponsive Polypeptide Brushes Prepared by Vapor Deposition Surface-Initiated Ring-Opening Polymerization of α-Amino Acid N -Carboxyanhydrides

    DOE PAGES

    Shen, Yong; Desseaux, Solenne; Aden, Bethany; ...

    2015-04-20

    We report that surface-grafting thermoresponsive polymers allows the preparation of thin polymer brush coatings with surface properties that can be manipulated by variation of temperature. In most instances, thermoresponsive polymer brushes are produced using polymers that dehydrate and collapse above a certain temperature. This report presents the preparation and properties of polymer brushes that show thermoresponsive surface properties, yet are shape-persistent in that they do not undergo main chain collapse. The polymer brushes presented here are obtained via vapor deposition surface-initiated ring-opening polymerization (SI-ROP) of γ-di- or tri(ethylene glycol)-modified glutamic acid N-carboxyanhydrides. Vapor deposition SI-ROP of γ-di- or tri(ethylene glycol)-modifiedmore » L- or D-glutamic acid N-carboxyanhydrides affords helical surface-tethered polymer chains that do not show any changes in secondary structure between 10 and 70 °C. QCM-D experiments, however, revealed significant dehydration of poly(γ-(2-(2-methoxyethoxy)ethyl)-l-glutamate) (poly(L-EG2-Glu)) brushes upon heating from 10 to 40 °C. At the same time, AFM and ellipsometry studies did not reveal significant variations in film thickness over this temperature range, which is consistent with the shape-persistent nature of these polypeptide brushes and indicates that the thermoresponsiveness of the films is primarily due to hydration and dehydration of the oligo(ethylene glycol) side chains. The results we present here illustrate the potential of surface-initiated NCA ring-opening polymerization to generate densely grafted assemblies of polymer chains that possess well-defined secondary structures and tunable surface properties. These polypeptide brushes complement their conformationally unordered counterparts that can be generated via surface-initiated polymerization of vinyl-type monomers and represent another step forward to biomimetic surfaces and interfaces.« less

  6. Abscisic Acid Participates in the Control of Cell Cycle Initiation Through Heme Homeostasis in the Unicellular Red Alga Cyanidioschyzon merolae.

    PubMed

    Kobayashi, Yuki; Ando, Hiroyuki; Hanaoka, Mitsumasa; Tanaka, Kan

    2016-05-01

    ABA is a phytohormone that is synthesized in response to abiotic stresses and other environmental changes, inducing various physiological responses. While ABA has been found in unicellular photosynthetic organisms, such as cyanobacteria and eukaryotic algae, its function in these organisms is poorly understood. Here, we found that ABA accumulated in the unicellular red alga Cyanidioschyzon merolae under conditions of salt stress and that the cell cycle G1/S transition was inhibited when ABA was added to the culture medium. A gene encoding heme-scavenging tryptophan-rich sensory protein-related protein (CmTSPO; CMS231C) was positively regulated by ABA, as in Arabidopsis, and CmTSPO bound heme in vitro. The intracellular content of total heme was increased by addition of ABA, but unfettered heme decreased, presumably due to scavenging by CmTSPO. The inhibition of DNA replication by ABA was negated by addition of heme to the culture medium. Thus, we propose a regulatory role for ABA and heme in algal cell cycle initiation. Finally, we found that a C. merolae mutant that is defective in ABA production was more susceptible to salt stress, indicating the importance of ABA to stress resistance in red algae. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  7. In Vitro Acid-Mediated Initial Dental Enamel Loss Is Associated with Genetic Variants Previously Linked to Caries Experience.

    PubMed

    Vieira, Alexandre R; Bayram, Merve; Seymen, Figen; Sencak, Regina C; Lippert, Frank; Modesto, Adriana

    2017-01-01

    We have previously shown that AQP5 and BTF3 genetic variation and expression in whole saliva are associated with caries experience suggesting that these genes may have a functional role in protecting against caries. To further explore these results, we tested ex vivo if variants in these genes are associated with subclinical dental enamel mineral loss. DNA and enamel samples were obtained from 53 individuals. Enamel samples were analyzed for Knoop hardness of sound enamel, integrated mineral loss after subclinical carious lesion creation, and change in integrated mineral loss after remineralization. DNA samples were genotyped for single nucleotide polymorphisms using TaqMan chemistry. Chi-square and Fisher's exact tests were used to compare individuals above and below the mean sound enamel microhardness of the cohort with alpha of 0.05. The A allele of BTF3 rs6862039 appears to be associated with harder enamel at baseline (p = 0.09), enamel more resistant to demineralization (p = 0.01), and enamel that more efficiently regain mineral and remineralize (p = 0.04). Similarly, the G allele of AQP5 marker rs3759129 and A allele of AQP5 marker rs296763 are associated with enamel more resistant to demineralization (p = 0.03 and 0.05, respectively). AQP5 and BTF3 genetic variations influence the initial subclinical stages of caries lesion formation in the subsurface of enamel.

  8. In Vitro Acid-Mediated Initial Dental Enamel Loss Is Associated with Genetic Variants Previously Linked to Caries Experience

    PubMed Central

    Vieira, Alexandre R.; Bayram, Merve; Seymen, Figen; Sencak, Regina C.; Lippert, Frank; Modesto, Adriana

    2017-01-01

    We have previously shown that AQP5 and BTF3 genetic variation and expression in whole saliva are associated with caries experience suggesting that these genes may have a functional role in protecting against caries. To further explore these results, we tested ex vivo if variants in these genes are associated with subclinical dental enamel mineral loss. DNA and enamel samples were obtained from 53 individuals. Enamel samples were analyzed for Knoop hardness of sound enamel, integrated mineral loss after subclinical carious lesion creation, and change in integrated mineral loss after remineralization. DNA samples were genotyped for single nucleotide polymorphisms using TaqMan chemistry. Chi-square and Fisher's exact tests were used to compare individuals above and below the mean sound enamel microhardness of the cohort with alpha of 0.05. The A allele of BTF3 rs6862039 appears to be associated with harder enamel at baseline (p = 0.09), enamel more resistant to demineralization (p = 0.01), and enamel that more efficiently regain mineral and remineralize (p = 0.04). Similarly, the G allele of AQP5 marker rs3759129 and A allele of AQP5 marker rs296763 are associated with enamel more resistant to demineralization (p = 0.03 and 0.05, respectively). AQP5 and BTF3 genetic variations influence the initial subclinical stages of caries lesion formation in the subsurface of enamel. PMID:28275354

  9. Synergistic activation of Arg1 gene by retinoic acid and IL-4 involves chromatin remodeling for transcription initiation and elongation coupling

    PubMed Central

    Lee, Bomi; Wu, Cheng-Ying; Lin, Yi-Wei; Park, Sung Wook; Wei, Li-Na

    2016-01-01

    All-trans Retinoic acid (RA) and its derivatives are potent therapeutics for immunological functions including wound repair. However, the molecular mechanism of RA modulation in innate immunity is poorly understood, especially in macrophages. We found that topical application of RA significantly improves wound healing and that RA and IL-4 synergistically activate Arg1, a critical gene for tissue repair, in M2 polarized macrophages. This involves feed forward regulation of Raldh2, a rate-limiting enzyme for RA biosynthesis, and requires Med25 to coordinate RAR, STAT6 and chromatin remodeler, Brg1 to remodel the +1 nucleosome of Arg1 for transcription initiation. By recruiting elongation factor TFIIS, Med25 also facilitates transcriptional initiation-elongation coupling. This study uncovers synergistic activation of Arg1 by RA and IL-4 in M2 macrophages that involves feed forward regulation of RA synthesis and dual functions of Med25 in nucleosome remodeling and transcription initiation-elongation coupling that underlies robust modulatory activity of RA in innate immunity. PMID:27166374

  10. Revisiting the mechanism of neutral hydrolysis of esters: water autoionization mechanisms with acid or base initiation pathways.

    PubMed

    da Silva, Poliana Lima; Guimarães, Luciana; Pliego, Josefredo R

    2013-05-30

    The mechanism of neutral hydrolysis of ester has long been explored by theoretical studies. However, reliable theoretical calculations show that the usual bifunctional catalysis mechanism reported by different authors cannot explain the experimental kinetics. An important advance was recently reported by Gunaydin and Houk, suggesting that ions are involved in the mechanism and the process initiates by water autoionization followed by protonation of the ester (W(AI)A mechanism). However, this mechanism does not explain the hydrolysis of activated esters. In this work, we have used ab initio calculations, continuum solvation models, and intrinsic reaction coordinate method to support the W(AI)A mechanism for normal ester. In the case of activated esters, the process can also be viewed as water autoionization with formation of hydroxide ion aided by a second water molecule acting as a general base (W(AI)B mechanism). This is the mechanism that was proposed by Jencks and Carriuolo 50 years ago. Our analysis point out that the usual method for exploring mechanisms, searching for saddle points, may not work for problems like the present one, since there are no saddle points on the reaction pathway. Rather, the formation of a pair of ions from a neutral species may have an asymptotic barrier. The approach used in this paper allows the calculation of the free energy profile and enable us to explain the mechanism and kinetics of the neutral hydrolysis of normal (methyl acetate) and activated (methyl trifluoroacetate) esters. In addition, the present study suggests that formation of a pair of ions should always be considered in reactions in aqueous solution.

  11. Kinetics of peroxidation of linoleic acid incorporated into DPPC vesicles initiated by the thermal decomposition of 2,2'-azobis(2-amidinopropane) dihydrochloride.

    PubMed

    Cubillos, M A; Lissi, E A; Abuin, E B

    2001-07-01

    In a previous work [Chem. Phys. Lipids 2000 104, 49], we have derived the following rate law for the oxidation of lipids in compartmentalized systems: R(T)=(k(1)/k(t))(0.5) k(p) [In](0.5) c(0.5) [LH], where, R(T) is the total rate of oxidation, k(1) is the rate constant for the production of free radicals, k(t) and k(p) are the intra-particle rate constants for the termination and propagation sets, respectively, [In] is the concentration of a water-soluble initiator, c is the concentration of particles, and [LH] is the intra-particle concentration of oxidable lipid. In the present work, we have investigated on the applicability of the proposed kinetic rate law for a system where it takes place the oxidation of a reactive lipid incorporated into an inert matrix. With this purpose, we have measured the rate of oxidation of linoleic acid incorporated into dipalmitoylphosphatidylcholine vesicles initiated by the thermal decomposition of 2,2'-azobis(2-amidinopropane) dihydrochloride as a function of the initiator, particles, and intra-particle LH concentrations. The experimentally determined kinetic orders obtained were 0.54+/-0.02, 0.48+/-0.05 and 0.83+/-0.04 for the dependence of the oxidation rate with initiator, particles, and LH intra-particle concentrations, respectively, in agreement with those theoretically predicted. The lower value obtained for the kinetic order in LH is attributed to a change in k(t) with the increase in oxidable lipid intra-particle concentration. The main point to be emphazised from the results here obtained is that the kinetic rate law for the oxidation of lipids in compartmentalized systems can be significantly different than that observed when to the oxidation takes place in homogeneous solution.

  12. The polar auxin transport inhibitor N-1-naphthylphthalamic acid disrupts leaf initiation, KNOX protein regulation, and formation of leaf margins in maize.

    PubMed

    Scanlon, Michael J

    2003-10-01

    Maize (Zea mays) leaves develop basipetally (tip to base); the upper blade emerges from the shoot apical meristem (SAM) before the expansion of the lower sheath. Founder cells, leaf initials located in the periphery of the SAM, are distinguished from the SAM proper by the differential accumulation of KNOX proteins. KNOX proteins accumulate in the SAM, but are excluded from maize leaf primordia and leaf founder cells. As in Arabidopsis and tomato (Lycopersicon esculentum), maize shoots failed to initiate new leaves when cultured in the polar auxin transport inhibitor N-1-naphthylphthalamic acid (NPA). We demonstrate that NPA-induced arrest of leaf initiation in maize is correlated with the failure to down-regulate KNOX accumulation in the SAM. In addition, NPA-cultured shoots formed abnormal tubular leaf bases in which the margins failed to separate in the lower leaf zone. The tubular leaf bases always formed in the fourth leaf from the arrested meristem. Moreover, the unseparated margin domains of these tubular leaf bases accumulated ectopic KNOX protein(s). Transfer of NPA-cultured apices to NPA-free media resulted in the resumption of leaf initiation from the SAM and the restoration of normal patterns of KNOX down-regulation, accordingly. These data suggest that the lower sheath margins emerge from the leaf base late in maize leaf development and that the separation of these leaf margin domains is correlated with auxin transport and down-regulation of KNOX proteins. In addition, these results suggest that the down-regulation of KNOX accumulation in maize apices is not upstream of polar auxin transport, although a more complicated feedback network may exist. A model for L1-derived margin development in maize leaves is presented.

  13. The association of red blood cell n-3 and n-6 fatty acids to dietary fatty acid intake, bone mineral density and hip fracture risk in The Women’s Health Initiative

    PubMed Central

    Orchard, Tonya S.; Ing, Steven W.; Lu, Bo; Belury, Martha A.; Johnson, Karen; Wactawski-Wende, Jean; Jackson, Rebecca D.

    2013-01-01

    Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFA) in red blood cells (RBC) are an objective indicator of PUFA status and may be related to hip fracture risk. The primary objective of this study was to examine RBC PUFAs as predictors of hip fracture risk in postmenopausal women. A nested case-control study (n=400 pairs) was completed within the Women’s Health Initiative (WHI) using 201 incident hip fracture cases from the Bone Mineral Density (BMD) cohort, along with 199 additional incident hip fracture cases randomly selected from the WHI Observational Study. Cases were 1:1 matched on age, race, and hormone use with non-hip fracture controls. Stored baseline RBCs were analyzed for fatty acids using gas chromatography. After removing degraded samples, 324 matched pairs were included in statistical analyses. Stratified Cox proportional hazard models were constructed according to case-control pair status; risk of fracture was estimated for tertiles of RBC PUFA. In adjusted hazard models, lower hip fracture risk was associated with higher RBC α-linolenic acid [Hazard ratio (HR) Tertile 3 (T3): 0.44; 95% CI: 0.23-0.85; p for linear trend 0.0154)], eicosapentaenoic acid (HR T3: 0.46; 95% CI: 0.24-0.87; p for linear trend 0.0181) and total n-3 PUFAs (HR T3: 0.55; 95% CI: 0.30-1.01; p for linear trend 0.0492). Conversely, hip fracture nearly doubled with the highest RBC n-6/n-3 ratio (HR T3: 1.96; 95% CI: 1.03-3.70; p for linear trend 0.0399). RBC PUFAs were not associated with BMD. RBC PUFAs were indicative of dietary intake of marine n-3 PUFAs (Spearman’s rho=0.45, p<0.0001), total n-6 PUFAs (rho=0.17, p<0.0001) and linoleic acid (rho= 0.09, p<0.05). These results suggest that higher RBC α-linolenic acid, as well as eicosapentaenoic acid and total n-3 PUFAs, may predict lower hip fracture risk. Contrastingly, a higher RBC n-6/n-3 ratio may predict higher hip fracture risk in postmenopausal women. PMID:23018646

  14. Fatty Acid Biosynthesis in Pseudomonas aeruginosa Is Initiated by the FabY Class of β-Ketoacyl Acyl Carrier Protein Synthases

    PubMed Central

    Yuan, Yanqiu; Sachdeva, Meena; Leeds, Jennifer A.

    2012-01-01

    The prototypical type II fatty acid synthesis (FAS) pathway in bacteria utilizes two distinct classes of β-ketoacyl synthase (KAS) domains to assemble long-chain fatty acids, the KASIII domain for initiation and the KASI/II domain for elongation. The central role of FAS in bacterial viability and virulence has stimulated significant effort toward developing KAS inhibitors, particularly against the KASIII domain of the β-acetoacetyl-acyl carrier protein (ACP) synthase FabH. Herein, we show that the opportunistic pathogen Pseudomonas aeruginosa does not utilize a FabH ortholog but rather a new class of divergent KAS I/II enzymes to initiate the FAS pathway. When a P. aeruginosa cosmid library was used to rescue growth in a fabH downregulated strain of Escherichia coli, a single unannotated open reading frame, PA5174, complemented fabH depletion. While deletion of all four KASIII domain-encoding genes in the same P. aeruginosa strain resulted in a wild-type growth phenotype, deletion of PA5174 alone specifically attenuated growth due to a defect in de novo FAS. Siderophore secretion and quorum-sensing signaling, particularly in the rhl and Pseudomonas quinolone signal (PQS) systems, was significantly muted in the absence of PA5174. The defect could be repaired by intergeneric complementation with E. coli fabH. Characterization of recombinant PA5174 confirmed a preference for short-chain acyl coenzyme A (acyl-CoA) substrates, supporting the identification of PA5174 as the predominant enzyme catalyzing the condensation of acetyl coenzyme A with malonyl-ACP in P. aeruginosa. The identification of the functional role for PA5174 in FAS defines the new FabY class of β-ketoacyl synthase KASI/II domain condensation enzymes. PMID:22753059

  15. Competition between functionalization and fragmentation pathways in the OH-initiated oxidation of aqueous tartaric acid droplets: Reaction products and model simulations

    NASA Astrophysics Data System (ADS)

    Cheng, C. T.; Chow, C. Y.; Chan, M. N.; Zuend, A.; Berkemeier, T.; Shiraiwa, M.

    2015-12-01

    To gain better insights into the competition between functionalization and fragmentation pathways for oxygenated organic compounds, we investigate the OH-radical initiated oxidation of aqueous tartaric acid (C4H6O6) droplets using an aerosol flow tube reactor. The molecular composition of reaction products is characterized by an atmospheric pressure ionization source (Direct Analysis in Real Time, DART) coupled with a high resolution mass spectrometer. The reaction produces four major products: a functionalization product (C4H4O6) and three fragmentation products (C3H4O4, C3H2O4 and C3H2O5), with a predominance of the functionalization product which supports the literature result that only less than 10% of carbon loss was observed for the OH oxidation of tartaric acid. The formation of the functionalization product (2-hydroxy-3-oxosuccinic acid, C4H4O6) can be attributed to that the tertiary alkyl radical, formed after hydrogen abstraction, reacts with an O2 molecule to form a hydroxyperoxyl radical which tends to quickly undergo intramolecular HO2 elimination without fragmentation. The molecular transformation of aqueous tartaric acid droplets is stimulated using the kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP) and the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model in order to take into account the change in particle-phase water and activities of reaction products during the oxidation. Results suggest that aqueous tartaric acid droplets become slightly less hygroscopic after oxidation due to the formation of less polar products. The formation of products with different hygroscopicities and volatilities largely determine the amount of particle-phase water, which in turn governs the size of the aqueous droplets and the concentration of the reactants. Consideration of the variation in water content in response to the chemical evolution in the aerosol is needed to better understand

  16. A common set of conserved motifs in a vast variety of putative nucleic acid-dependent ATPases including MCM proteins involved in the initiation of eukaryotic DNA replication.

    PubMed Central

    Koonin, E V

    1993-01-01

    A new superfamily of (putative) DNA-dependent ATPases is described that includes the ATPase domains of prokaryotic NtrC-related transcription regulators, MCM proteins involved in the initiation of eukaryotic DNA replication, and a group of uncharacterized bacterial and chloroplast proteins. MCM proteins are shown to contain a modified form of the ATP-binding motif and are predicted to mediate ATP-dependent opening of double-stranded DNA in the replication origins. In a second line of investigation, it is demonstrated that the products of unidentified open reading frames from Marchantia mitochondria and from yeast, and a domain of a baculovirus protein involved in viral DNA replication are related to the superfamily III of DNA and RNA helicases that previously has been known to include only proteins of small viruses. Comparison of the multiple alignments showed that the proteins of the NtrC superfamily and the helicases of superfamily III share three related sequence motifs tightly packed in the ATPase domain that consists of 100-150 amino acid residues. A similar array of conserved motifs is found in the family of DnaA-related ATPases. It is hypothesized that the three large groups of nucleic acid-dependent ATPases have similar structure of the core ATPase domain and have evolved from a common ancestor. PMID:8332451

  17. Initial inhomogeneity-induced crazy-clock behavior in the iodate-arsenous acid reaction in a buffered medium under stirred batch conditions.

    PubMed

    Valkai, László; Csekő, György; Horváth, Attila K

    2015-09-14

    It is unambiguously demonstrated that in the case of an autocatalytic reaction, initial inhomogeneities induced by the imperfectly mixed part of the overall volume may result in a serious irreproducibility of the individual kinetic runs. A statistically meaningful number of repetitions, however, gives rise to a reproducible cumulative probability distribution curve often referred to as a support of the stochastic feature. The iodate-arsenous acid reaction being autocatalytic with respect to both iodide and hydrogen ions displays clock behavior. However, the time lag necessary for the appearance of iodine, even in buffered solution, varies in an apparently random manner. Careful analysis of the variation of the different parameters like stirring rate, overall volume, geometry of the reactor and the way of mixing the reactants led us to conclude that the fate of the individual samples is determined at the initial stage when the reacting system is per se inhomogeneous. The place, the size of the so-called ignition volume, where the reacting system is imperfectly stirred, as well as the residence time spent there by the imperfectly mixed reactants all seem to depend on external factors.

  18. Treatment with α-Lipoic Acid over 16 Weeks in Type 2 Diabetic Patients with Symptomatic Polyneuropathy Who Responded to Initial 4-Week High-Dose Loading

    PubMed Central

    Garcia-Alcala, Hector; Santos Vichido, Celia Isabel; Islas Macedo, Silverio; Genestier-Tamborero, Christelle Nathalie; Minutti-Palacios, Marissa; Hirales Tamez, Omara; García, Carlos; Ziegler, Dan

    2015-01-01

    Effective treatment of diabetic sensorimotor polyneuropathy remains a challenge. To assess the efficacy and safety of α-lipoic acid (ALA) over 20 weeks, we conducted a multicenter randomized withdrawal open-label study, in which 45 patients with type 2 diabetes and symptomatic polyneuropathy were initially treated with ALA (600 mg tid) for 4 weeks (phase 1). Subsequently, responders were randomized to receive ALA (600 mg qd; n = 16) or to ALA withdrawal (n = 17) for 16 weeks (phase 2). During phase 1, the Total Symptom Score (TSS) decreased from 8.9 ± 1.8 points to 3.46 ± 2.0 points. During phase 2, TSS improved from 3.7 ± 1.9 points to 2.5 ± 2.5 points in the ALA treated group (p < 0.05) and remained unchanged in the ALA withdrawal group. The use of analgesic rescue medication was higher in the ALA withdrawal group than ALA treated group (p < 0.05). In conclusion, in type 2 diabetic patients with symptomatic polyneuropathy who responded to initial 4-week high-dose (600 mg tid) administration of ALA, subsequent treatment with ALA (600 mg qd) over 16 weeks improved neuropathic symptoms, whereas ALA withdrawal was associated with a higher use of rescue analgesic drugs. This trial is registered with ClinicalTrials.gov Identifier: NCT02439879. PMID:26345602

  19. Treatment with α-Lipoic Acid over 16 Weeks in Type 2 Diabetic Patients with Symptomatic Polyneuropathy Who Responded to Initial 4-Week High-Dose Loading.

    PubMed

    Garcia-Alcala, Hector; Santos Vichido, Celia Isabel; Islas Macedo, Silverio; Genestier-Tamborero, Christelle Nathalie; Minutti-Palacios, Marissa; Hirales Tamez, Omara; García, Carlos; Ziegler, Dan

    2015-01-01

    Effective treatment of diabetic sensorimotor polyneuropathy remains a challenge. To assess the efficacy and safety of α-lipoic acid (ALA) over 20 weeks, we conducted a multicenter randomized withdrawal open-label study, in which 45 patients with type 2 diabetes and symptomatic polyneuropathy were initially treated with ALA (600 mg tid) for 4 weeks (phase 1). Subsequently, responders were randomized to receive ALA (600 mg qd; n = 16) or to ALA withdrawal (n = 17) for 16 weeks (phase 2). During phase 1, the Total Symptom Score (TSS) decreased from 8.9 ± 1.8 points to 3.46 ± 2.0 points. During phase 2, TSS improved from 3.7 ± 1.9 points to 2.5 ± 2.5 points in the ALA treated group (p < 0.05) and remained unchanged in the ALA withdrawal group. The use of analgesic rescue medication was higher in the ALA withdrawal group than ALA treated group (p < 0.05). In conclusion, in type 2 diabetic patients with symptomatic polyneuropathy who responded to initial 4-week high-dose (600 mg tid) administration of ALA, subsequent treatment with ALA (600 mg qd) over 16 weeks improved neuropathic symptoms, whereas ALA withdrawal was associated with a higher use of rescue analgesic drugs. This trial is registered with ClinicalTrials.gov Identifier: NCT02439879.

  20. Lack of initiation activity of 4-oxo-2-hexenal, a peroxidation product generated from omega-3 polyunsaturated fatty acids, in an in vivo five-week liver assay.

    PubMed

    Takasu, Shinji; Tsukamoto, Tetsuya; Hirata, Akihiro; Kawai, Kazuaki; Toyoda, Takeshi; Ban, Hisayo; Sakai, Hiroki; Yanai, Tokuma; Masegi, Toshiaki; Kasai, Hiroshi; Tatematsu, Masae

    2007-01-01

    Peroxidation products formed from polyunsaturated lipids have DNA damaging potential. 4-oxo-2-hexenal (4-OHE), generated by the oxidation of omega-3 fatty acids, has been demonstrated to be mutagenic in vitro as assessed in the Ames test. To examine the carcinogenic risk of 4-OHE in vivo, initiation activity was investigated in a five-week liver assay, established to be effective for screening of carcinogenic potential of mutagens. Seven-week-old male F344 rats underwent two-thirds partial hepatectomy (PH) and were administered 4-OHE intragastrically at doses of 128, 80, 64, 40, 32, 20, or 0 mg/kg body weight (b.w.) at 18 hours thereafter, then being fed on diet containing 0.015% 2-acetylaminofluorene from weeks 2 to 4. All rats were given with 0.8 ml/kg b.w. CCl4 at week 3. At week 5, all survivors were sacrificed and initiation activity was assessed with reference to induction of glutathione S-transferase placental form (GST-P) positive foci in the liver. Mortality was significantly increased to 72.7% in the 128 mg/kg b.w. dose group compared with 0.9% in the control group. However, the average number of GST-P positive foci in the "128" dose group was 3.26-/+1.66 foci/cm2, not significantly different from the control value (2.78?1.33). Areas of GST-P positive foci were also similar (1.11-/+0.5 and 1.53-/+1.33 mm2/cm2 in "128" and the control groups, respectively). These results showed 4-OHE to have no significant initiation activity in.

  1. Erythrocyte omega-3 fatty acids are inversely associated with incident dementia: Secondary analyses of longitudinal data from the Women's Health Initiative Memory Study (WHIMS).

    PubMed

    Ammann, Eric M; Pottala, James V; Robinson, Jennifer G; Espeland, Mark A; Harris, William S

    2017-06-01

    To assess whether red blood cell (RBC) docosahexaenoic acid and eicosapentaenoic acid (DHA+EPA) levels have a protective association with the risk of dementia in older women. RBC DHA+EPA levels were assessed at baseline, and cognitive status was evaluated annually in a cohort of 6706 women aged ≥65 years who participated in the Women's Health Initiative Memory Study (WHIMS). Cox regression was used to quantify the association between RBC DHA+EPA and the risk of probable dementia, independent of major dementia risk factors. During a median follow-up period of 9.8 years, 587 incident cases of probable dementia were identified. After adjusting for demographic, clinical, and behavioral risk factors, a one standard deviation increase in DHA+EPA levels was associated with a significantly lower risk of dementia (HR = 0.92, 95% CI: 0.84, 1.00; p < 0.05). This effect estimate did not meaningfully change after further adjustment for baseline cognitive function and APOE genotype. For women with high DHA+EPA exposure (1SD above mean) compared to low exposure (1SD below mean), the adjusted 15-year absolute risk difference for dementia was 2.1% (95% CI: 0.2%, 4.0%). In secondary analyses, we also observed a protective association with longitudinal change in Modified Mini-Mental State (3MS) Exam scores, but no significant association with incident MCI, PD/MCI, or baseline 3MS scores. Higher levels of DHA+EPA may help protect against the development of dementia. Results from prospective randomized controlled trials of DHA+EPA supplementation are needed to help clarify whether this association is causal. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Effect of Dietary Treatment with Dimethylarsinous Acid (DMAIII) on the Urinary Bladder Epithelium of Arsenic (+3 Oxidation State) Methyltransferase (As3mt) Knockout and C57BL/6 Wild Type Female Mice

    EPA Science Inventory

    Abstract Chronic exposure to inorganic arsenic (iAs) is carcinogenic to the human urinary bladder. It produces urothelial cytotoxicity and proliferation in rats and mice. DMAv, a major methylated urinary metabolite of iAs, is a rat bladder carcinogen, but without effects on the...

  3. Effect of Dietary Treatment with Dimethylarsinous Acid (DMAIII) on the Urinary Bladder Epithelium of Arsenic (+3 Oxidation State) Methyltransferase (As3mt) Knockout and C57BL/6 Wild Type Female Mice

    EPA Science Inventory

    Abstract Chronic exposure to inorganic arsenic (iAs) is carcinogenic to the human urinary bladder. It produces urothelial cytotoxicity and proliferation in rats and mice. DMAv, a major methylated urinary metabolite of iAs, is a rat bladder carcinogen, but without effects on the...

  4. Antimicrobial activity of lactic acid bacteria isolated from Tenerife cheese: initial characterization of plantaricin TF711, a bacteriocin-like substance produced by Lactobacillus plantarum TF711.

    PubMed

    Hernández, D; Cardell, E; Zárate, V

    2005-01-01

    The screening and initial characterization of bacteriocins produced by lactic acid bacteria (LAB) from raw Tenerife goats' cheese with possible application as biopreservatives or ripening accelerators for Tenerife cheese. One hundred and eighty LAB of the genera Lactobacillus (95), Leuconostoc (64) and Lactococcus (21) isolated from raw Tenerife goats' cheese were screened for the production of antimicrobial substances. Lactobacillus plantarum TF711, which had the broadest spectrum of antimicrobial activity, was selected for further characterization. The antimicrobial compound was determined as a proteinaceous substance, as it was sensitive to proteases. The bacteriocin-like substance, which we called plantaricin TF711, was active against the Gram-positive bacteria Bacillus cereus, Clostridium sporogenes and Staphylococcus aureus; and against the Enterobacteriaceae Shigella sonnei and Klebsiella pneumoniae. It was stable to heat and to treatment with surfactants and organic solvents. Highest antimicrobial activity was found between pH 1 and 9. Plantaricin TF711 exhibited primary metabolite kinetics, a bacteriostatic mode of action and a molecular mass of c. 2.5 kDa as determined by tricine SDS-PAGE. Lact. plantarum TF711 produces a low molecular mass bacteriocin-like compound with a wide spectrum of activity and interesting technological properties (thermostability, good pH stability and stability against surfactants and organic solvents). Plantaricin TF711 was found to have potential for use as a biopreservative in the food industry.

  5. pH-responsive controlled-release fertilizer with water retention via atom transfer radical polymerization of acrylic acid on mussel-inspired initiator.

    PubMed

    Ma, Zhi-yuan; Jia, Xin; Zhang, Guo-xiang; Hu, Jia-mei; Zhang, Xiu-lan; Liu, Zhi-yong; Wang, He-yun; Zhou, Feng

    2013-06-12

    This work reports a polydopamine-graft-poly(acrylic acid) (Pdop-g-PAA)-coated controlled-release multi-element compound fertilizer with water-retention function by a combination of mussel-inspired chemistry and surface-initiated atom transfer radical polymerization (SI-ATRP) techniques for the first time. The morphology and composition of the products were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and inductively coupled plasma (ICP) emission spectrometry. The results revealed that the stimuli-responsive layer formed by a Pdop inner layer and a PAA outer corona exhibit outstanding selective permeability to charged nutrients and the release rate of encapsulated elements can be tailored by the pH values. At low pH, the Pdop-g-PAA layer can reduce nutrient loss, and at high pH, the coating restrains transportation of negative nutrients but favors the release of cations. Moreover, PAA brushes provide good water-retention property. This Pdop-graft-polymer brushes coating will be effective and promising in the research and development of multi-functional controlled-release fertilizer.

  6. Development of a complex amino acid supplement, Fatigue Reviva™, for oral ingestion: initial evaluations of product concept and impact on symptoms of sub-health in a group of males

    PubMed Central

    2013-01-01

    Background A new dietary supplement, Fatigue Reviva™, has been recently developed to address issues related to amino acid depletion following illness or in conditions of sub-health where altered amino acid homeostasis has been associated with fatigue. Complex formulations of amino acids present significant challenges due to solubility and taste constraints. This initial study sets out to provide an initial appraisal of product palatability and to gather pilot evidence for efficacy. Methods Males reporting symptoms of sub-health were recruited on the basis of being free from any significant medical or psychological condition. Each participant took an amino acid based dietary supplement (Fatigue Reviva™) daily for 30 days. Comparisons were then made between pre- and post-supplement general health symptoms and urinary amino acid profiles. Results Seventeen men took part in the study. Following amino acid supplementation the total Chalder fatigue score improved significantly (mean ± SEM, 12.5 ± 0.9 versus 10.0 ± 1.0, P<0.03). When asked whether they thought that the supplement had improved their health, 65% of participants responded positively. A subgroup of participants reported gastrointestinal symptoms which were attributed to the supplement and which were believed to result from the component fructooligosaccharide. Analysis of urinary amino acids revealed significant alterations in the relative abundances of a number of amino acids after supplementation including an increase in valine, isoleucine and glutamic acid and reduced levels of glutamine and ornithine. Discriminant function analysis of the urinary amino acid data revealed significant differences between the pre- and post-supplement urine excretion profiles. Conclusions The results indicated that Fatigue Reviva™ was palatable and that 65% of the study group reported that they felt the product had improved their health. The product could provide an effective tool for the management of unexplained

  7. Expression of Cell-Surface Marker ABCB5 Causes Characteristic Modifications of Glucose, Amino Acid and Phospholipid Metabolism in the G3361 Melanoma-Initiating Cell Line

    PubMed Central

    Lutz, Norbert W.; Banerjee, Pallavi; Wilson, Brian J.; Ma, Jie; Cozzone, Patrick J.; Frank, Markus H.

    2016-01-01

    We present a pilot study aimed at determining the effects of expression of ATP-binding cassette member B5 (ABCB5), a previously described marker for melanoma-initiating cells, on cellular metabolism. Metabolic profiles for two groups of human G3361 melanoma cells were compared, i.e. wildtype melanoma cells with intact ABCB5 expression (ABCB5-WT) and corresponding melanoma cell variants with inhibited ABCB5 expression, through shRNA-mediated gene knockdown (ABCB5-KD). A comprehensive metabolomic analysis was performed by using proton and phosphorus NMR spectroscopy of cell extracts to examine water-soluble metabolites and lipids. Parametric and non-parametric statistical analysis of absolute and relative metabolite levels yielded significant differences for compounds involved in glucose, amino acid and phospholipid (PL) metabolism. By contrast, energy metabolism was virtually unaffected by ABCB5 expression. The sum of water-soluble metabolites per total protein was 17% higher in ABCB5-WT vs. ABCB5-KD G3361 variants, but no difference was found for the sum of PLs. Enhanced abundance was particularly pronounced for lactate (+ 23%) and alanine (+ 26%), suggesting an increase in glycolysis and potentially glutaminolysis. Increases in PL degradation products, glycerophosphocholine and glycerophosphoethanolamine (+ 85 and 123%, respectively), and redistributions within the PL pool suggested enhanced membrane PL turnover as a consequence of ABCB5 expression. The possibility of glycolysis modulation by an ABCB5-dependent IL1β-mediated mechanism was supported by functional studies employing monoclonal antibody (mAb)-dependent ABCB5 protein inhibition in wildtype G3361 melanoma cells. Our metabolomic results suggest that the underlying biochemical pathways may offer targets for melanoma therapy, potentially in combination with other treatment forms. PMID:27560924

  8. Initial amino acid intake influences phosphorus and calcium homeostasis in preterm infants--it is time to change the composition of the early parenteral nutrition.

    PubMed

    Bonsante, Francesco; Iacobelli, Silvia; Latorre, Giuseppe; Rigo, Jacques; De Felice, Claudio; Robillard, Pierre Yves; Gouyon, Jean Bernard

    2013-01-01

    Early aggressive parenteral nutrition (PN), consisting of caloric and nitrogen intake soon after birth, is currently proposed for the premature baby. Some electrolyte disturbances, such as hypophosphatemia and hypercalcemia, considered unusual in early life, were recently described while using this PN approach. We hypothesize that, due to its impact on cell metabolism, the initial amino acid (AA) amount may specifically influence the metabolism of phosphorus, and consequently of calcium. We aim to evaluate the influence of AA intake on calcium-phosphorus metabolism, and to create a calculation tool to estimate phosphorus needs. Prospective observational study. Phosphate and calcium plasma concentrations and calcium balance were evaluated daily during the first week of life in very preterm infants, and their relationship with nutrition was studied. For this purpose, infants were divided into three groups: high, medium and low AA intake (HAA, MAA, LAA). A calculation formula to assess phosphorus needs was elaborated, with a theoretical model based on AA and calcium intake, and the cumulative deficit of phosphate intake was estimated. 154 infants were included. Hypophosphatemia (12.5%) and hypercalcemia (9.8%) were more frequent in the HAA than in the MAA (4.6% and 4.8%) and in the LAA group (0% and 1.9%); both p<0.001. Calcium-phosphorus homeostasis was influenced by the early AA intake. We propose to consider phosphorus and calcium imbalances as being part of a syndrome, related to incomplete provision of nutrients after the abrupt discontinuation of the placental nutrition at birth (PI-ReFeeding syndrome). We provide a simple tool to calculate the optimal phosphate intake. The early introduction of AA in the PN soon after birth might be completed by an early intake of phosphorus, since AA and phosphorus are (along with potassium) the main determinants of cellular growth.

  9. Initial Amino Acid Intake Influences Phosphorus and Calcium Homeostasis in Preterm Infants – It Is Time to Change the Composition of the Early Parenteral Nutrition

    PubMed Central

    Bonsante, Francesco; Iacobelli, Silvia; Latorre, Giuseppe; Rigo, Jacques; De Felice, Claudio; Robillard, Pierre Yves; Gouyon, Jean Bernard

    2013-01-01

    Background Early aggressive parenteral nutrition (PN), consisting of caloric and nitrogen intake soon after birth, is currently proposed for the premature baby. Some electrolyte disturbances, such as hypophosphatemia and hypercalcemia, considered unusual in early life, were recently described while using this PN approach. We hypothesize that, due to its impact on cell metabolism, the initial amino acid (AA) amount may specifically influence the metabolism of phosphorus, and consequently of calcium. We aim to evaluate the influence of AA intake on calcium-phosphorus metabolism, and to create a calculation tool to estimate phosphorus needs. Methods Prospective observational study. Phosphate and calcium plasma concentrations and calcium balance were evaluated daily during the first week of life in very preterm infants, and their relationship with nutrition was studied. For this purpose, infants were divided into three groups: high, medium and low AA intake (HAA, MAA, LAA). A calculation formula to assess phosphorus needs was elaborated, with a theoretical model based on AA and calcium intake, and the cumulative deficit of phosphate intake was estimated. Results 154 infants were included. Hypophosphatemia (12.5%) and hypercalcemia (9.8%) were more frequent in the HAA than in the MAA (4.6% and 4.8%) and in the LAA group (0% and 1.9%); both p<0.001. Discussion Calcium-phosphorus homeostasis was influenced by the early AA intake. We propose to consider phosphorus and calcium imbalances as being part of a syndrome, related to incomplete provision of nutrients after the abrupt discontinuation of the placental nutrition at birth (PI-ReFeeding syndrome). We provide a simple tool to calculate the optimal phosphate intake. The early introduction of AA in the PN soon after birth might be completed by an early intake of phosphorus, since AA and phosphorus are (along with potassium) the main determinants of cellular growth. PMID:23977367

  10. Lycopene metabolite, apo-10'-lycopenoic acid, inhibits diethylnitrosamine-initiated, high fat diet-promoted hepatic inflammation and tumorigenesis in mice.

    PubMed

    Ip, Blanche C; Hu, Kang-Quan; Liu, Chun; Smith, Donald E; Obin, Martin S; Ausman, Lynne M; Wang, Xiang-Dong

    2013-12-01

    Obesity is associated with increased risk in hepatocellular carcinoma (HCC) development and mortality. An important disease control strategy is the prevention of obesity-related hepatic inflammation and tumorigenesis by dietary means. Here, we report that apo-10'-lycopenoic acid (APO10LA), a cleavage metabolite of lycopene at its 9',10'-double bond by carotene-9',10'-oxygenase, functions as an effective chemopreventative agent against hepatic tumorigenesis and inflammation. APO10LA treatment on human liver THLE-2 and HuH7 cells dose dependently inhibited cell growth and upregulated sirtuin 1 (SIRT1), a NAD(+)-dependent protein deacetylase that may suppress hepatic carcinogenesis. This observed SIRT1 induction was associated with decreased cyclin D1 protein, increased cyclin-dependent kinase inhibitor p21 protein expression, and induced apoptosis. APO10LA supplementation (10 mg/kg diet) for 24 weeks significantly reduced diethylnitrosamine-initiated, high fat diet (HFD)-promoted hepatic tumorigenesis (50% reduction in tumor multiplicity; 65% in volume) and lung tumor incidence (85% reduction) in C57Bl/6J mice. The chemopreventative effects of APO10LA were associated with increased hepatic SIRT1 protein and deacetylation of SIRT1 targets, as well as with decreased caspase-1 activation and SIRT1 protein cleavage. APO10LA supplementation in diet improved glucose intolerance and reduced hepatic inflammation [decreased inflammatory foci, TNFα, interleukin (IL)-6, NF-κB p65 protein expression, and STAT3 activation] in HFD-fed mice. Furthermore, APO10LA suppressed Akt activation, cyclin D1 gene, and protein expression and promoted PARP protein cleavage in transformed cells within liver tumors. Taken together, these data indicate that APO10LA can effectively inhibit HFD-promoted hepatic tumorigenesis by stimulating SIRT1 signaling while reducing hepatic inflammation.

  11. Higher Levels of CRP, D-dimer, IL-6, and Hyaluronic Acid Before Initiation of Antiretroviral Therapy (ART) Are Associated With Increased Risk of AIDS or Death

    PubMed Central

    Boulware, David R.; Hullsiek, Katherine Huppler; Puronen, Camille E.; Rupert, Adam; Baker, Jason V.; French, Martyn A.; Bohjanen, Paul R.; Novak, Richard M.; Neaton, James D.

    2011-01-01

    Background. Substantial morbidity occurs during the first year of antiretroviral therapy (ART) in persons with advanced human immunodeficiency virus (HIV) disease despite HIV suppression. Biomarkers may identify high-risk groups. Methods. Pre-ART and 1-month samples from an initial ART trial were evaluated for biomarkers associated with AIDS events or death within 1–12 months. Case patients (n = 63) and control patients (n = 126) were 1:2 matched on baseline CD4 cell count, hepatitis status, and randomization date. All had ≥1 log10 HIV RNA level decrease at 1 month. Results. Case patients had more frequent prior AIDS events, compared with control patients (P = .004), but similar HIV RNA levels at baseline. Pre-ART and 1-month C-reactive protein (CRP), D-dimer, and interleukin 6 (IL-6) levels and pre-ART hyaluronic acid (HA) levels were associated with new AIDS events or death (P ≤ .01). Patients who experienced immune reconstitution inflammatory syndrome (IRIS) events had higher pre-ART tumor necrosis factor α (TNF-α) and HIV RNA levels and significant 1-month increases in CRP, D-dimer, IL-6, interleukin 8, CXCL10, TNF-α, and interferon-γ levels, compared with patients who experienced non-IRIS events (P ≤ .03). Individuals with baseline CRP and HA levels above the cohort median (>2.1 mg/L and >50.0 ng/mL, respectively) had increased risk of AIDS or death (OR, 4.6 [95% CI, 2.0–10.3]; P < .001) and IRIS (OR, 8.7 [95% CI, 2.2–34.8] P = .002). Conclusions. Biomarkers of Inflammation (CRP, IL-6), coagulation (D-dimer), and tissue fibrosis (HA) measured pre-ART and at 1 month are associated with higher risk of AIDS events, IRIS, or death, warranting additional study as risk stratification strategies. PMID:21592994

  12. 3-mercaptopropionate dioxygenase, a cysteine dioxygenase homologue, catalyzes the initial step of 3-mercaptopropionate catabolism in the 3,3-thiodipropionic acid-degrading bacterium variovorax paradoxus.

    PubMed

    Bruland, Nadine; Wübbeler, Jan Hendrik; Steinbüchel, Alexander

    2009-01-02

    The thioether 3,3-thiodipropionic acid can be used as precursor substrate for biotechnological synthesis of 3-mercaptopropionic acid-containing polythioesters. Therefore, the hitherto unknown catabolism of this compound was elucidated to engineer novel and improved polythioester biosynthesis pathways in the future. Bacteria capable of using 3,3-thiodipropionic acid as the sole source of carbon and energy for growth were enriched from the environment. From eleven isolates, TBEA3, TBEA6, and SFWT were morphologically and physiologically characterized. Their 16 S rDNAs and other features affiliated these isolates to the beta-subgroup of the proteobacteria. Tn5::mob mutagenesis of isolate Variovorax paradoxus TBEA6 yielded ten mutants fully or partially impaired in growth on 3,3-thiodipropionic acid. Genotypic characterization of two 3,3-thiodipropionic acid-negative mutants demonstrated the involvement of a bacterial cysteine dioxygenase (EC 1.13.11.22) homologue in the further catabolism of the 3,3-thiodipropionic acid cleavage product 3-mercaptopropionic acid. Detection of 3-sulfinopropionate in the supernatant of one of these mutants during cultivation on 3,3-thiodipropionic acid as well as in vivo and in vitro enzyme assays using purified protein demonstrated oxygenation of 3-mercaptopropionic acid to 3-sulfinopropionate by this enzyme; cysteine and cysteamine were not used as substrate. Beside cysteine dioxygenase and cysteamine dioxygenase, this 3-mercaptopropionic acid dioxygenase is the third example for a thiol dioxygenase and the first report about the microbial catabolism of 3-mercaptopropionic acid. Insertion of Tn5::mob in a gene putatively coding for a family III acyl-CoA-transferase resulted in the accumulation of 3-sulfinopropionate during cultivation on 3,3-thiodipropionic acid, indicating that this compound is further metabolized to 3-sulfinopropionyl-CoA and subsequently to propionyl-CoA.

  13. Earlier Initiation and Use of a Greater Number of Iron-Folic Acid Supplements during Pregnancy Prevents Early Neonatal Deaths in Nepal and Pakistan

    PubMed Central

    Nisar, Yasir Bin; Dibley, Michael J.

    2014-01-01

    Introduction Early neonatal deaths account for 75% of neonatal deaths globally. Antenatal iron-folic acid (IFA) supplementation has significantly reduced the risk of early neonatal deaths in China and Indonesia. We investigated the impact of antenatal IFA supplements on the risk of early neonatal deaths in Nepal and Pakistan during the last decade. Methods Data from the most recent singleton live-births of 8,186 from two Nepal Demographic and Health Surveys (DHS) and 13,034 from two Pakistan DHS were selected for the current study. The primary outcome was early neonatal deaths and the main study variable was antenatal IFA supplementation. Analyses used multivariate Cox proportional regression, adjusted for the cluster sampling design and for 18 potential confounders. Findings The adjusted risk of early neonatal deaths was significantly reduced by 51% (aHR = 0.49, 95% CI = 0.32–0.75) in Nepal and 23% (aHR = 0.77, 95% CI = 0.59–0.99) in Pakistan with any use of IFA compared to none. When IFA supplementation started at or before the 5th month of pregnancy, the adjusted risk of early neonatal mortality was significantly reduced by 53% in Nepal, and 28% in Pakistan, compared to no IFA. When >90 IFA supplements were used and started at or before 5th months, the adjusted risk of early neonatal deaths was significantly reduced by 57% in Nepal, and 45% in Pakistan. In Nepal 4,600 and in Pakistan 75,000 early neonatal deaths could be prevented annually if all pregnant women used >90 IFA supplements and started at or before the 5th month of pregnancy. Conclusions Any use of IFA supplements was significantly associated with reduced risk of early neonatal deaths in Nepal and Pakistan. The greatest mortality sparing effect of IFA on early neonatal deaths in both countries was with early initiation and use of a greater number of supplements. PMID:25398011

  14. Red-Light Initiated Decomposition of α-Hydroxy Methylperoxy Radical in the Presence of Organic and Inorganic Acids: Implications for the HOx Formation in the Lower Stratosphere.

    PubMed

    Kumar, Manoj; Francisco, Joseph S

    2016-05-05

    Theoretical calculations have been carried out to investigate the gas-phase decomposition of α-hydroxy methylperoxy (HOCH2(OO)) radical in the absence and presence of formic acid, acetic acid, nitric acid, and sulfuric acid. The HOCH2(OO) radical decomposition represents a new source of the HOx radical in troposphere. The results suggest that sulfuric acid will be more effective than other acids in catalyzing the peroxy radical decomposition. However, the significant stability of prereaction and postreaction complexes in all the bimolecular reactions implies a new photomechanism for the acid-mediated decomposition of the HOCH2(OO) radical that involves the visible or near IR overtone excitation of the OH stretching modes or electronic excitation of the O-O peroxy moiety in the acid-bound radical. This new overtone or electronic excitation-based photomechanism for the peroxy radical decomposition may provide useful insight into the missing photolytic source of the HOx at high solar zenith angles corresponding to the dawn or dusk photochemistry.

  15. A review of the developments of self-etching primers and adhesives -Effects of acidic adhesive monomers and polymerization initiators on bonding to ground, smear layer-covered teeth.

    PubMed

    Ikemura, Kunio; Kadoma, Yoshinori; Endo, Takeshi

    2011-01-01

    This paper reviews the developments of self-etching primers and adhesives, with a special focus on the effect of acidic adhesive monomers and polymerization initiators on bonding to ground, smear layer-covered teeth. Ionized acidic adhesive monomers chemically interact with tooth substrates and facilitate good bonding to ground dentin. Polymerization initiators in self-etching primers further promote effective bonding to ground dentin. To promote bonding to both dentin and enamel, phosphonic acid monomers such as 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA) were developed. These novel adhesive monomers also have a water-soluble nature and are hence endowed with sufficient demineralization capability. A new single-bottle, self-etching, 2-hydroxyethyl methacrylate (HEMA)-free adhesive comprising 6-MHPA and 4-acryloyloxyethoxycarbonylphthalic acid (4-AET) was developed. This novel adhesive enabled strong adhesion to both ground enamel and dentin, but its formulation stability was influenced by pH value of the adhesive. To develop hydrolytically stable, single-bottle, self-etching adhesives, hydrolytically stable, radical-polymerizable acidic monomers with amide or ether linkages have been developed.

  16. A novel metabolic activation associated with glutathione in dimethylmonothioarsinic acid (DMMTA(V))-induced toxicity obtained from in vitro reaction of DMMTA(V) with glutathione.

    PubMed

    Kurosawa, Hidetoshi; Shimoda, Yasuyo; Miura, Motofumi; Kato, Koichi; Yamanaka, Kenzo; Hata, Akihisa; Yamano, Yuko; Endo, Yoko; Endo, Ginji

    2016-01-01

    The purpose of the present study was to elucidate the metabolic processing of dimethylmonothioarsinic acid (DMMTA(V)), which is a metabolite of inorganic arsenic and has received a great deal of attention recently due to its high toxicity. The metabolites produced from an in vitro reaction with GSH were analyzed by high performance liquid chromatography-time of flight mass spectrometer (HPLC-TOFMS), HPLC with a photodiode array detector (PDA), and also gas chromatography-mass spectrometry (GC-MS) and GC with a flame photometric detector (FPD). The reaction of dimethylarsinic acid (DMA(V)) with GSH did not generate DMA(V)-SG but did generate dimethylarsinous acid (DMA(III)) or DMA(III)-SG. On the contrary, we confirmed that the reaction of DMMTA(V) with GSH directly produced the stable complex of DMMTA(V)-SG without reduction through a trivalent dimethylated arsenic such as DMA(III) and DMA(III)-SG. Furthermore, the present study suggests the production of hydrogen sulfide (H2S) and dimethylmercaptoarsine (DMA(III)-SH), a trivalent dimethylated arsenic, as well as DMA(III) and DMA(III)-SG in the decomposition process of DMMTA(V)-SG. These results indicate that the toxicity of DMMTA(V) depends not only on the formation of DMA(III) but also on at least those of H2S and DMA(III)-SH. Copyright © 2015 Elsevier GmbH. All rights reserved.

  17. Heat-initiated prebiotic formation of peptides from glycine/aspartic acid and glycine/valine in aqueous environment and clay suspension

    NASA Astrophysics Data System (ADS)

    Pant, Chandra Kala; Lata, Hem; Pathak, Hari Datt; Mehata, Mohan Singh

    2009-04-01

    The effect of heat on the reaction system of glycine/aspartic acid and glycine/valine in the aqueous environment as well as in montmorillonite clay suspension with or without divalent cations (Ca2+, Mg2+ and Ni2+) has been investigated at 85°C±5°C for varying periods under prebiotic drying and wetting conditions. The resulting products were analysed and characterized by chromatographic and spectroscopic methods. Peptide formation appears to depend on the duration of heat effect, nature of reactant amino acids and, to some extent, on montmorillonite clay incorporated with divalent cations. In the glycine/aspartic acid system, oligomerization of glycine was limited up to trimer level (Gly)3 along with the formation of glycyl-aspartic acid, while linear and cyclic peptides of aspartic acid were not formed, whereas the glycine/valine system preferentially elongated homo-oligopeptide of glycine up to pentamer level (Gly)5 along with formation of hetero-peptides (Gly-Val and Val-Gly). These studies are relevant in the context of the prebiotic origin of proteins and the role of clay and metal ions in condensation and oligomerization of amino acids. The length of the bio-oligomer chain depends upon the reaction conditions. However, condensation into even a small length seems significant, as the same process would have taken millions of years in the primitive era of the Earth, leading to the first proteins.

  18. Initial Characterization of Carbon Metabolism in Iron Oxidizing Microbial Communities of Acidic Hot Springs in Norris Geyser Basin, Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Kreuzer, H. W.; Jennings, R. D.; Whitmore, L.; Inskeep, W. P.; Moran, J.

    2012-12-01

    Norris Geyser Basin in Yellowstone National Park is home to several acidic, sulfidic hot springs. Visual inspection of the springs reveals distinct geochemical regions starting with a sulfur deposition zone followed by a transition to iron oxide deposition downstream. The microbial communities in the iron oxidation zones are dominated by Archaea, including several members that appear to define previously unrecognized taxa. Abiotic iron oxidation rates are very slow at these temperatures (typically ~ 65-70 oC) and pH's (typically ~3). Therefore, the relatively rapid iron oxide deposition rate strongly suggests the process is microbially mediated, and an organism previously isolated from these springs, Metallosphaera yellowstonensis, has been shown to oxide iron in culture. M. yellowstonensis has been observed in the all microbial communities analyzed in the iron oxidizing zones of these springs, though metagenomic profiling suggests it constitutes only ~20% of the community membership. When we began our studies of C flow in the iron-oxidizing community, no C source had been demonstrated. Observed potential carbon sources in the springs include dissolved inorganic carbon, dissolved organic carbon, and methane, as well as random inputs of heterotrophic carbon in the forms of insect carcasses, pine needles, and animal scat. The temperatures in the iron oxidation zones are above the photosynthetic upper temperature limit, thus precluding photosynthetic-based autotrophy within the community itself. We are employing geochemical and stable isotope techniques to assess carbon inventories in the system. We have demonstrated that M. yellowstonensis as well as excised samples of iron oxide mat communities can fix CO2, and our estimated isotopic fractionation factor is consistent with the 3-hydroxypropionate 4-hydroxybutyrate pathway. Genes of this pathway have been identified in the M. yellowstonensis genome. We have tentatively identified small amounts of organic compounds

  19. Purification and initial characterization of the 71-kilodalton rat heat-shock protein and its cognate as fatty acid binding proteins.

    PubMed

    Guidon, P T; Hightower, L E

    1986-06-03

    The major rat heat-shock (stress) protein and its cognate were purified to electrophoretic homogeneity from livers of heat-shocked rats. Both proteins exhibited similar behavior on a variety of column chromatography matrices but were separable by preparative isoelectric focusing under nondenaturing conditions by virtue of a 0.2 pH unit difference in isoelectric point. Both purified proteins had similar physical properties, suggesting the possibility that they may have similar biological functions as well. Both proteins were homodimers under nondissociative conditions (Mr 150 000) with isoelectric points of 5.0 (cognate) and 5.2 (major stress protein). After denaturation, both proteins had an increase in isoelectric point of 0.6 pH unit, and the resulting polypeptide chains had apparent molecular weights of 73 000 (cognate) and 71 000 (major stress protein). Similarities in the electrophoretic properties of these two proteins and serum albumin, which also undergoes a large basic shift in isoelectric point due to loss of fatty acids and conformational changes accompanying denaturation, prompted us to search for lipids associated with the purified 71-kilodalton stress protein and its cognate. Thin-layer chromatography of chloroform/methanol extracts of these two proteins revealed nonesterified fatty acids bound to both proteins. Palmitic acid, stearic acid, and a small amount of myristic acid were identified by gas chromatography/mass spectroscopy. Both proteins contained approximately four molecules of fatty acid per dimer with palmitate and stearate present in a one to one molar ratio. Possible roles of the major stress protein and its cognate as fatty acid associated proteins in cellular responses to stress are discussed.

  20. Characterization of pH-Responsive Hydrogels of Poly(Itaconic acid-g-Ethylene Glycol) Prepared by UV-Initiated Free Radical Polymerization as Biomaterials for Oral Delivery of Bioactive Agents

    PubMed Central

    Betancourt, Tania; Pardo, Juan; Soo, Ken; Peppas, Nicholas A.

    2009-01-01

    Effective oral delivery of proteins is impeded by steep pH gradients and proteolytic enzymes in the gastrointestinal tract, as well as low absorption of the proteins into the bloodstream due to their size, charge or solubility. In the present work, pH-responsive complexation hydrogels of poly(itaconic acid) with poly(ethylene glycol) grafts were synthesized for applications in oral drug delivery. These hydrogels were expected to be in collapsed configuration at low pH due to hydrogen bonding between poly(itaconic acid) carboxyl groups and poly(ethylene glycol), and to swell with increasing pH because of charge repulsion between deprotonated carboxylic acid groups. Hydrogels were prepared by UV-initiated free radical polymerization using tetraethylene glycol as the crosslinking agent and Irgacure® 2959 as the initiator. The effect of monomer ratios, crosslinking ratio and solvent amount on the properties of the hydrogels were investigated. The composition of the hydrogels was confirmed by FTIR. Equilibrium swelling studies in the pH range of 1.2 to 7 revealed that the extent of swelling increased with increasing pH up to a pH of about 6, when no further carboxylic acid deprotonation occurred. Studies in Caco-2 colorectal carcinoma cells confirmed the cytocompatibility of these materials at concentrations of up to 5 mg/ml. PMID:19536838

  1. Metabolism and excretion of orally and intraperitoneally administered methylarsonic acid in the hamster

    SciTech Connect

    Yamauchi, H.; Yamato, N.; Yamamura, Y.

    1988-02-01

    A number of investigators have demonstrated that when inorganic arsenic is administered to humans and experimental animals, methylarsonic acid (MAA) is formed in vivo. Low concentrations of MAA have been detected in human organs and urine. Few studies of the metabolism and elimination of MAA have been published. Following administration of a single oral dose of MAA to human subject, it was reported that MAA was rapidly metabolized to dimethylarsinic acid (DMAA) in vivo and excreted in urine. While the elimination of MAA has been investigated experimentally in animals, nothing is known of MAA metabolism and distribution in vivo. In the present study, the metabolism of MAA was investigated following its administration to hamsters. Arsenic species deposited in selected organs and blood, and the amounts and chemical species of arsenic excreted in urine and feces were determined.

  2. Mapping of the Frazee Mine, the Western Maryland Coal Combustion By-Products/Acid Mine Drainage Initiative, Part 2 of 3

    SciTech Connect

    Egers, K.M.; Rafalko, L.G.; Petzrick, P.; Duckett, G.; Beck, L.A.

    1996-12-31

    Maryland coal production over the years before 1977 reveals that Maryland coal basins have void space from mining a quarter billion tons of coal. The exposure of sulfur-bearing minerals in these mine voids to oxygen and water generates AMD, which is toxic to aquatic flora and fauna. It is estimated that about 450 miles of waterways in western Maryland are impacted by AMD. The majority of these waterways ultimately drain to the east, and affect the overall water quality of the Chesapeake Bay. Typically, AMD is treated by dosing discharges with limestone, which only provides a temporary solution as AMD continues to form at its source in underground mines. The Maryland Department of Natural Resources (DNR) Power Plant Research Program (PPRP) and the Maryland Department of the Environment Bureau of Mines (MDE) have undertaken the Western Maryland CCB/AMD Initiative (the Initiative), which is a joint effort with private industry to develop permanent solutions to abate AMD at its source. The Initiative`s goal is to demonstrate the beneficial application of alkaline CCBs to abate AMD from underground coal mines. The Initiative is based on the concept that alkaline CCBs generated by clean coal technologies, such as fluidized bed combustion (FBC) and flue gas desulfurization (FGD), can be injected into underground mines to prevent the formation of AMD by sealing mines from exposure to oxygen and water. This goal will be met by performing the following: Determining optimum grout formulations for mine injection; Optimizing engineering techniques for mine reclamation to achieve economic viability; Implementing appropriately-sized demonstration projects, progressing to full-scale applications at Maryland`s largest abandoned mines; and Developing industry partnerships for implementation of the Initiative`s findings to abate AMD in western Maryland.

  3. Determination of arsenic species in solid matrices utilizing supercritical fluid extraction coupled with gas chromatography after derivatization with thioglycolic acid n-butyl ester.

    PubMed

    Wang, Zhifeng; Cui, Zhaojie

    2016-12-01

    A method using derivatization and supercritical fluid extraction coupled with gas chromatography was developed for the analysis of dimethylarsinate, monomethylarsonate and inorganic arsenic simultaneously in solid matrices. Thioglycolic acid n-butyl ester was used as a novel derivatizing reagent. A systematic discussion was made to investigate the effects of pressure, temperature, flow rate of the supercritical CO2 , extraction time, concentration of the modifier, and microemulsion on extraction efficiency. The application for real environmental samples was also studied. Results showed that thioglycolic acid n-butyl ester was an effective derivatizing reagent that could be applied for arsenic speciation. Using methanol as modifier of the supercritical CO2 can raise the extraction efficiency, which can be further enhanced by adding a microemulsion that contains Triton X-405. The optimum extraction conditions were: 25 MPa, 90°C, static extraction for 10 min, dynamic extraction for 25 min with a flow rate of 2.0 mL/min of supercritical CO2 modified by 5% v/v methanol and microemulsion. The detection limits of dimethylarsinate, monomethylarsonate, and inorganic arsenic in solid matrices were 0.12, 0.26, and 1.1 mg/kg, respectively. The optimized method was sensitive, convenient, and reliable for the extraction and analysis of different arsenic species in solid samples.

  4. Lycopene metabolite, apo-10'-lycopenoic acid, inhibits diethylnitrosamine-initiated, high fat diet-promoted hepatic inflammation and tumorigenesis in mice

    USDA-ARS?s Scientific Manuscript database

    Obesity is associated with increased risk in hepatocellular carcinoma (HCC) development and mortality. An important disease control strategy is the prevention of obesity-related hepatic inflammation and tumorigenesis by dietary means. Here, we report that apo-10'-lycopenoic acid (APO10LA), a cleavag...

  5. [Insulin: initiation of pool of insulin-dependent cells, targeted transfer of triglycerides and increase of kinetic parameters of oxidation of fatty acids].

    PubMed

    Titov, V N

    2014-04-01

    The insulin, to provide with energy the biological function of locomotion, formed: a) pool of phylogenetically late insulin-dependent cells; b) highly productive vector variant of transfer of saturated and mono unsaturated fatty acids only to insulin-dependent cells; c) new variant of active absorption of substrates for acquiring energy by cells--apoE/B-100-receptor endocytosis; d) transformation of all endogenically synthesized palmitic saturated fatty acid in oleic mono saturated fatty acid and e) replacement of potentially ineffective palmitic variant of formation of energy in vivo with potentially high-performance oleic variant of metabolism of substrates for turning out of ATP. The insulin expressed synthesis of apoE glucose carrier 4 and stearyl-KoA-desaturase. These occurrences confirm that syndrome of insulin resistance primarily is the pathology of metabolism of fatty acids and only secondary the pathology metabolism of glucose. The multi-functional fatty cells of visceral areolar tissue and specialized adipocytes of subcutaneous fat depots are phylogenetically, regulatory and functionally different cells. They are formed under development of different biological functions: the first ones under realization of biological function of trophology and second ones under realization of biological function of locomotion. At the level of organism, the mechanisms of hypothalamus-fatty cells feedback are realized by peptide leptin and in case of hypothalamus-adipocytes feedback--peptide adiponectin. The potential possibilities of mitochondria in synthesis of ATP are high and are conditioned only by amount of substrate of mitochondria acetyl-KoA. This shortage can be chronic as in cases of disorder of insulin function and palmitic variant of metabolism of substrates for acquiring energy by cells. The deficiency of acetyl-KoA can be acute as is the case of diabetic coma when surplus amount of ketonic bodies follows the expressed deficiency of acetyl-KoA formed from

  6. Influence of steroid-hormone-receptor-protein complexes on initiation of ribonucleic acid synthesis in liver nuclei isolated from rats of various ages.

    PubMed Central

    Miller, J K; Bolla, R

    1981-01-01

    The effect of age on the induction of the initiation of RNA synthesis was investigated in liver nuclei isolated from adrenalectomized rats of various ages after binding of a dexamethasone-receptor-protein complex. Binding of this complex to nuclear chromatin resulted in increased initiation of nuclear RNA synthesis at all ages; however, an age-associated decline in the extent of this induction was observed. This suggests an age-related decrease of total rat liver nuclear RNA synthesis with a decreased response to glucocorticoid hormones. PMID:6171268

  7. The highly conserved amino acid sequence motif Tyr-Gly-Asp-Thr-Asp-Ser in alpha-like DNA polymerases is required by phage phi 29 DNA polymerase for protein-primed initiation and polymerization.

    PubMed Central

    Bernad, A; Lázaro, J M; Salas, M; Blanco, L

    1990-01-01

    The alpha-like DNA polymerases from bacteriophage phi 29 and other viruses, prokaryotes and eukaryotes contain an amino acid consensus sequence that has been proposed to form part of the dNTP binding site. We have used site-directed mutants to study five of the six highly conserved consecutive amino acids corresponding to the most conserved C-terminal segment (Tyr-Gly-Asp-Thr-Asp-Ser). Our results indicate that in phi 29 DNA polymerase this consensus sequence, although irrelevant for the 3'----5' exonuclease activity, is essential for initiation and elongation. Based on these results and on its homology with known or putative metal-binding amino acid sequences, we propose that in phi 29 DNA polymerase the Tyr-Gly-Asp-Thr-Asp-Ser consensus motif is part of the dNTP binding site, involved in the synthetic activities of the polymerase (i.e., initiation and polymerization), and that it is involved particularly in the metal binding associated with the dNTP site. Images PMID:2191296

  8. Routine delayed voiding cystourethography after initial successful endoscopic treatment with Dextranomer/Hialuronic Acid Copolimer (Dx/HA) of vesicoureteral reflux (VUR). Is it necessary?

    PubMed

    García-Aparicio, L; Blázquez-Gómez, E; Vila Santandreu, A; Camacho Diaz, J A; Vila-Cots, J; Ramos Cebrian, M; de Haro, I; Martin, O; Tarrado, X

    2016-12-01

    Some guidelines recommend an early voiding cystourethrography (VCUG) after endoscopic treatment of vesicoureteral reflux (VUR), but there's no consensus if it's necessary a long-term follow-up in these patients. The aim of our study is analyze if it's necessary a delayed VCUG after initial successful treatment with Dx/HA. We have reviewed all medical charts of patients that underwent Dx/HA treatment from 2006 to 2010. We have selected patients with initial successful treatment and more than 3 years of radiological and clinical follow-up. We have analyzed late clinical and radiological outcomes. One hundred and sixty children with 228 refluxing ureters underwent Dx/HA endoscopic treatment with a mean follow-up of 52.13 months. Early VCUG was performed in 215 ureters with an initial successful rate of 84.1%. The group of study was 94/215 ureters with more than 3 years of follow-up with a delayed VCUG. VUR was still resolved in 79,8% of the ureters. Clinical success rate was 91.7%. The incidence of febrile urinary tract infection in those patients with cured VUR and those with a relapsed VUR was 8 and 15%, respectively; but there were no significant differences. We have not found any variable related with relapsed VUR except those ureters that initially received 2 injections (P<.05). If our objective in the treatment of VUR is to reduce the incidence of febrile urinary tract infection it is not necessary to perform a delayed VCUG even though the long-term radiological outcomes is worse than clinical outcome. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. The long-term effect of initial pH control on the enrichment culture of phosphorus- and glycogen-accumulating organisms with a mixture of propionic and acetic acids as carbon sources.

    PubMed

    Zhang, Chao; Chen, Yinguang; Liu, Yan

    2007-11-01

    In most studies on phosphorus- and glycogen-accumulating organisms (PAO and GAO), pH was controlled constantly throughout the entire anaerobic and aerobic periods, and acetic acid was used as the carbon source. In this paper, the effect of long-term initial pH values on PAO and GAO was investigated with mixed propionic and acetic acids as carbon sources. It was observed that with pH increasing from 6.4 to 8.0, the anaerobic propionic acid uptake rate by PAO linearly increased but that by GAO proportionally decreased. At pH 6.70 and pH 7.51, PAO and GAO exhibited the same acetic and propionic acid uptake rates, respectively. The acetic acid uptake rate by PAO was greater than that by GAO at pH>6.70, and the propionic acid uptake rate by PAO was higher than that by GAO at pH>7.51, which indicated that PAO would take predominance over GAO at pH>7.51. Poly-3-hydroxybutyrate, poly-3-hydroxyvalerate and poly-3-hydroxy-2-methylvalerate shared 7%, 62% and 31%, respectively in the PAO system, and 11%, 44% and 45% respectively in the GAO system, and these fractions were observed independent of pH either in the PAO or in the GAO system. In the PAO system, with the increase of pH, the phosphorus removal efficiency was improved greatly, and a phosphorus removal efficiency of 100% was achieved at 8.0. Further investigation showed that the higher phosphorus removal efficiency at higher pH was mainly caused by a biological effect instead of chemical one.

  10. Studies on sex-organ development. Changes in chromatin structure during spermatogenesis in maturing rooster testis as demonstrated by the initiation pattern of ribonucleic acid synthesis in vitro.

    PubMed Central

    Mezquita, C; Teng, C S

    1978-01-01

    To probe the structural change in the genome of the differentiating germ cell of the maturing rooster testis, the chromatin from nuclei at various stages of differentiation were transcribed with prokaryotic RNA polymerase from Escherichia coli or with eukaryotic RNA polymerase II from wheat germ. The transcription was performed under conditions of blockage of RNA chain reinitiation in vitro with rifampicin or rifampicin AF/013. With the E. coli enzyme, the changes in (1) the titration curve for the enzyme-chromatin interaction, (2) the number of initiation sites, (3) the rate of elongation of RNA chains, and (4) the kinetics of the formation of stable initiation complexes revealed the unmasking of DNA in elongated spermatids and the masking of DNA in spermatozoa. In both cases the stability of the DNA duplex in the initiation region for RNA synthesis greatly increased. In contrast with the E. coli enzyme, the wheat-germ RNA polymerase II was relatively inefficient at transcribing chromatin of elongated spermatids. Such behaviour can be predicted if unmasked double-stranded DNA is present in elongated spermatids. PMID:346018

  11. A low energy electron microscopy study of the initial growth, structure, and thermal stability of 4,4'-biphenyldicarboxylic acid domains on Cu(001)

    NASA Astrophysics Data System (ADS)

    Khokhar, Fawad S.; van Gastel, Raoul; Schwarz, Daniel; Zandvliet, Harold J. W.; Poelsema, Bene

    2011-09-01

    The growth of 4,4'-biphenyldicarboxylic acid (BDA) on Cu(001) has been studied using low energy electron microscopy and selective area low energy electron diffraction. The emergence of large islands and hydrogen bonding to perpendicularly oriented, adjacent molecules is confirmed. The two benzene rings of adsorbed BDA are twisted along the molecular axis. Unconventional growth of the domains, followed by a second nucleation stage, is observed at room temperature. This unanticipated feature is attributed to the accumulation of stress in the islands. Ostwald ripening in the films and the decay of BDA domains at 448 K exhibits features that are consistent with diffusion limited behavior.

  12. Folic acid supplementation lowers blood arsenic2

    PubMed Central

    Gamble, Mary V; Liu, Xinhua; Slavkovich, Vesna; Pilsner, J Richard; Ilievski, Vesna; Factor-Litvak, Pam; Levy, Diane; Alam, Shafiul; Islam, Mominul; Parvez, Faruque; Ahsan, Habibul; Graziano, Joseph H

    2007-01-01

    Background Chronic arsenic exposure currently affects >100 million persons worldwide. Methylation of ingested inorganic arsenic (InAs) to monomethylarsonic (MMAs) and dimethylarsinic (DMAs) acids relies on folate-dependent one-carbon metabolism and facilitates urinary arsenic elimination. Objective We hypothesized that folic acid supplementation to arsenic-exposed Bangladeshi adults would increase arsenic methylation and thereby lower total blood arsenic. Design In this randomized, double-blind, placebo-controlled trial, we evaluated blood concentrations of total arsenic, InAs, MMAs, and DMAs in 130 participants with low plasma folate (<9 nmol/L) before and after 12 wk of supplementation with folic acid (400 μg/d) or placebo. Results MMAs in blood was reduced by a mean ± SE of 22.24 ± 2.86% in the folic acid supplementation group and by 1.24 ± 3.59% in the placebe group (P < 0.0001). There was no change in DMAs in blood; DMAs is rapidly excreted in urine as evidenced by an increase in urinary DMAs (P = 0.0099). Total blood arsenic was reduced by 13.62% in the folic acid supplementation group and by 2.49% in the placebo group (P = 0.0199). Conclusions Folic acid supplementation to participants with low plasma concentrations of folate lowered blood arsenic concentrations, primarily by decreasing blood MMAs and increasing urinary DMAs. Therapeutic strategies to facilitate arsenic methylation, particularly in populations with folate deficiency or hyperhomocysteinemia or both, may lower blood arsenic concentrations and thereby contribute to the prevention of arsenic-induced illnesses. PMID:17921403

  13. Ports Initiative

    EPA Pesticide Factsheets

    EPA's Ports Initiative works in collaboration with the port industry, communities, and government to improve environmental performance and increase economic prosperity. This effort helps people near ports breath cleaner air and live better lives.

  14. Total syntheses of the squalene-derived halogenated polyethers ent-dioxepandehydrothyrsiferol and armatol A via bromonium- and Lewis acid-initiated epoxide-opening cascades

    PubMed Central

    Underwood, Brian S.; Tanuwidjaja, Jessica; Ng, Sze-Sze; Jamison, Timothy F.

    2013-01-01

    Herein we describe in full our investigations leading to the first total syntheses of ent-dioxepandehydrothyrsiferol and armatol A. Discovery of a bromonium-initiated epoxide-opening cascade enabled novel tactics for constructing key fragments found in both natural products and have led us to revise the proposed biogeneses. Other common features found in the routes include convergent fragment coupling strategies to assemble the natural products’ backbones and the use of epoxide-opening cascades for rapid constructions of the fused polyether subunits. Through de novo synthesis of armatol A, we elucidate the absolute and relative configuration of this natural product. PMID:23878408

  15. Leucine-induced activation of translational initiation is partly regulated by the branched-chain {alpha}-keto acid dehydrogenase complex in C2C12 cells

    SciTech Connect

    Nakai, Naoya . E-mail: nakai@hss.osaka-u.ac.jp; Shimomura, Yoshiharu; Tamura, Tomohiro; Tamura, Noriko; Hamada, Koichiro; Kawano, Fuminori; Ohira, Yoshinobu

    2006-05-19

    Branched-chain amino acid leucine has been shown to activate the translational regulators through the mammalian target of rapamycin. However, the leucine's effects are self-limiting because leucine promotes its own disposal by an oxidative pathway. The irreversible and rate-limiting step in the leucine oxidation pathway is catalyzed by the branched-chain {alpha}-keto acid dehydrogenase (BCKDH) complex. The complex contains E1 ({alpha}2{beta}2), E2, and E3 subunits, and its activity is abolished by phosphorylation of the E1{alpha} subunit by BCKDH kinase. The relationship between the activity of BCKDH complex and leucine-mediated activation of the protein translation was investigated using the technique of RNA interference. The activity of BCKDH complex in C2C12 cell was modulated by transfection of small interfering RNA (siRNA) for BCKDH E2 subunit or BCKDH kinase. Transfection of siRNAs decreased the mRNA expression and protein amount of corresponding gene. Suppression of either E2 subunit or kinase produced opposite effects on the cell proliferation and the activation of translational regulators by leucine. Suppression of BCKDH kinase for 48 h resulted in decreasing cell proliferation. In contrast, E2 suppression led to increased amount of total cellular protein. The phosphorylation of p70 S6 kinase by leucine was increased in E2-siRNA transfected C2C12 cells, whereas the leucine's effect was diminished in kinase-siRNA transfected cells. These results suggest that the activation of the translational regulators by leucine was partly regulated by the activity of BCKDH complex.

  16. Development and initial evaluation of a novel method for assessing tissue-specific plasma free fatty acid utilization in vivo using (R)-2-bromopalmitate tracer.

    PubMed

    Oakes, N D; Kjellstedt, A; Forsberg, G B; Clementz, T; Camejo, G; Furler, S M; Kraegen, E W; Olwegård-Halvarsson, M; Jenkins, A B; Ljung, B

    1999-06-01

    We describe a method for assessing tissue-specific plasma free fatty acid (FFA) utilization in vivo using a non-beta-oxidizable FFA analog, [9,10-3H]-(R)-2-bromopalmitate (3H-R-BrP). Ideally 3H-R-BrP would be transported in plasma, taken up by tissues and activated by the enzyme acyl-CoA synthetase (ACS) like native FFA, but then 3H-labeled metabolites would be trapped. In vitro we found that 2-bromopalmitate and palmitate compete equivalently for the same ligand binding sites on albumin and intestinal fatty acid binding protein, and activation by ACS was stereoselective for the R-isomer. In vivo, oxidative and non-oxidative FFA metabolism was assessed in anesthetized Wistar rats by infusing, over 4 min, a mixture of 3H-R-BrP and [U-14C] palmitate (14C-palmitate). Indices of total FFA utilization (R*f) and incorporation into storage products (Rfs') were defined, based on tissue concentrations of 3H and 14C, respectively, 16 min after the start of tracer infusion. R*f, but not Rfs', was substantially increased in contracting (sciatic nerve stimulated) hindlimb muscles compared with contralateral non-contracting muscles. The contraction-induced increases in R*f were completely prevented by blockade of beta-oxidation with etomoxir. These results verify that 3H-R-BrP traces local total FFA utilization, including oxidative and non-oxidative metabolism. Separate estimates of the rates of loss of 3H activity indicated effective 3H metabolite retention in most tissues over a 16-min period, but appeared less effective in liver and heart. In conclusion, simultaneous use of 3H-R-BrP and [14C]palmitate tracers provides a new useful tool for in vivo studies of tissue-specific FFA transport, utilization and metabolic fate, especially in skeletal muscle and adipose tissue.

  17. Ultrahigh-field imaging of the biliary tract at 7 T: initial results of gadoxetic acid-enhanced magnetic resonance cholangiography.

    PubMed

    Fischer, Anja; Kraff, Oliver; Orzada, Stephan; Nensa, Felix; Schäfer, Lena C; Ladd, Mark E; Umutlu, Lale; Lauenstein, Thomas C

    2014-05-01

    The objectives of this study were to assess the feasibility of magnetic resonance cholangiography (MRC) using biliary-secreted gadoxetic acid at 7 T and to compare it with T2-weighted (w) MRC at 3 T. Ten healthy volunteers were examined on a 7-T whole-body magnetic resonance system. T2-weighted turbo-spin-echo sequence, T1-w volume-interpolated breath-hold examination (VIBE), and fast low-angle shot (FLASH) with inversion recovery (IR) were acquired in coronal orientation. For dynamic imaging, gadoxetic acid was administrated and data were collected for a period of 5 to 40 minutes after injection. The volunteers underwent subsequent T2-w respiratory-gated MRC at 3 T. For qualitative analysis, a 5-point scale was used. Contrast ratios (CRs) were calculated for quantitative assessment. Contrast-enhanced T1-w MRC at 7 T showed a homogeneous depiction of the intrahepatic and extrahepatic biliary tract with a maximum enhancement of 20 minutes after contrast. Volume-interpolated breath-hold examination and FLASH IR provided a good image quality for the intrahepatic (VIBE, 3.60; FLASH IR, 3.67) and extrahepatic bile ducts (VIBE, 3.50; FLASH IR, 3.72). The quantitative analysis revealed high CR values for FLASH IR (intrahepatic CR, 0.41; extrahepatic CR, 0.45) because of an effective suppression of hepatic tissue and vessels. The T2-w TSE at 7 T showed only a poor image quality without diagnostic potential (intrahepatic, 2.22; extrahepatic, 1.93). Seven-tesla VIBE and FLASH revealed superiority in the depiction of the intrahepatic bile ducts, whereas 3-T MRC was superior in the delineation of the extrahepatic biliary tract. Our results demonstrate the feasibility of contrast-enhanced imaging of the biliary ducts at 7 T.

  18. Changes in ascorbic acid content in primary cultured rat hepatocytes exposed to 2,2'-azobis (2-amidinopropane) dihydrochloride, a radical initiator.

    PubMed

    Sasakii, K; Kimura, K; Kitaguchi, Y; Onoue, T; Ogura, H; Aoyagi, Y

    2001-08-01

    Changes in ascorbate content in primary cultured rat hepatocytes exposed to oxidative stress derived from water soluble radical initiator 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) were examined. Cells were exposed to 0.05 and 5 mg/ml of AAPH as 'mild' and severe' oxidative stresses, respectively. Lipid peroxidation in hepatocytes was induced by 'severe' oxidative stress, but not by 'mild' oxidative stress. Ascorbate decreased at 6 hr after administration of both mild' and severe' oxidative stresses, and recovered to the control level after a further 6 hr. In cells treated with 'severe oxidative stress, however, total ascorbate (reduced form plus oxidized form) had increased 24 hr after administration. These results indicated that consumption alone did not account for the increase of ascorbate in hepatocytes under oxidative stress.

  19. Skeletal muscle–specific eukaryotic translation initiation factor 2α phosphorylation controls amino acid metabolism and fibroblast growth factor 21–mediated non–cell-autonomous energy metabolism

    PubMed Central

    Miyake, Masato; Nomura, Akitoshi; Ogura, Atsushi; Takehana, Kenji; Kitahara, Yoshihiro; Takahara, Kazuna; Tsugawa, Kazue; Miyamoto, Chinobu; Miura, Naoko; Sato, Ryosuke; Kurahashi, Kiyoe; Harding, Heather P.; Oyadomari, Miho; Ron, David; Oyadomari, Seiichi

    2016-01-01

    The eukaryotic translation initiation factor 2α (eIF2α) phosphorylation-dependent integrated stress response (ISR), a component of the unfolded protein response, has long been known to regulate intermediary metabolism, but the details are poorly worked out. We report that profiling of mRNAs of transgenic mice harboring a ligand-activated skeletal muscle–specific derivative of the eIF2α protein kinase R-like ER kinase revealed the expected up-regulation of genes involved in amino acid biosynthesis and transport but also uncovered the induced expression and secretion of a myokine, fibroblast growth factor 21 (FGF21), that stimulates energy consumption and prevents obesity. The link between the ISR and FGF21 expression was further reinforced by the identification of a small-molecule ISR activator that promoted Fgf21 expression in cell-based screens and by implication of the ISR-inducible activating transcription factor 4 in the process. Our findings establish that eIF2α phosphorylation regulates not only cell-autonomous proteostasis and amino acid metabolism, but also affects non–cell-autonomous metabolic regulation by induced expression of a potent myokine.—Miyake, M., Nomura, A., Ogura, A., Takehana, K., Kitahara, Y., Takahara, K., Tsugawa, K., Miyamoto, C., Miura, N., Sato, R., Kurahashi, K., Harding, H. P., Oyadomari, M., Ron, D., Oyadomari, S. Skeletal muscle–specific eukaryotic translation initiation factor 2α phosphorylation controls amino acid metabolism and fibroblast growth factor 21–mediated non–cell-autonomous energy metabolism. PMID:26487695

  20. Production of doubly-charged highly reactive species from the long-chain amino acid GABA initiated by Ar(9+) ionization.

    PubMed

    Piekarski, Dariusz Grzegorz; Delaunay, Rudy; Mika, Arkadiusz; Maclot, Sylvain; Adoui, Lamri; Martín, Fernando; Alcamí, Manuel; Huber, Bernd A; Rousseau, Patrick; Díaz-Tendero, Sergio; Domaracka, Alicja

    2017-08-02

    We present a combined experimental and theoretical study of the fragmentation of multiply-charged γ-aminobutyric acid molecules (GABA(z+), z = 2, 3) in the gas phase. The combination of ab initio molecular dynamics simulations with multiple-coincidence mass spectrometry techniques allows us to observe and identify doubly-charged fragments in coincidence with another charged moiety. The present results indicate that double and triple electron capture lead to the formation of doubly-charged reactive nitrogen and oxygen species (RNS and ROS) with different probabilities due to the different charge localisation and fragmentation behaviour of GABA(2+) and GABA(3+). The MD simulations unravel the fast (femtosecond) formation of large doubly charged species, observed on the experimental microsecond timescale. The excess of positive charge is stabilised by the presence of cyclic X-member (X = 3-5) ring structures. 5-Member cyclic molecules can sequentially evaporate neutral moieties, such as H2, H2O and CO2, leading to smaller doubly charged fragments as those observed in the experiments.

  1. Youth Initiatives.

    ERIC Educational Resources Information Center

    Employment and Training Administration (DOL), Washington, DC. Office of Youth Programs.

    Summarizing the first eight months of the planning, design, and implementation of the new federal youth programs created by the Youth Employment and Demonstration Projects Act of 1977 (YEDPA) and the efforts for expansion and enrichment of the Job Corps, this report explains the charters of the two projects and their initial successes in and…

  2. Treatment outcomes in relapsed acute promyelocytic leukemia patients initially treated with all-trans retinoic acid and arsenic compound-based combined therapies.

    PubMed

    Lu, Jin; Huang, Xiaojun; Bao, Li; Jiang, Hao; Zhu, Honghu; Jiang, Bin

    2014-01-01

    Contemporary combined therapies that include the use of all-trans retinoic acid (ATRA) and arsenic compounds have reduced relapse rates from ~50 to <10% in acute promyelocytic leukemia (APL) patients, however relapse treatment remains controversial. Treatment outcomes in relapsed patients with APL previously treated with combined ATRA + arsenic compound therapy were investigated. A retrospective, observational study was conducted of 25 patients with APL (male to female ratio, 17:8; mean age, 36.4±10.3 years) exhibiting first-time relapse following combined ATRA + arsenic compound therapy. These patients were subsequently treated with secondary ATRA + arsenic compound therapy, salvage chemotherapy, monoclonal antibody therapy or intrathecal chemotherapy, between January 1994 and December 2010. The overall remission rate, duration of remission and toxic effects were assessed. Patient outcomes included mortality during secondary induction therapy (6/25, 24.0%); complete recovery from central nervous system (CNS) relapse following intrathecal chemotherapy (1/25, 4.0%); complete remission following ATRA + arsenic compound therapy (10/25, 40.0%), chemotherapy (3/25, 12.0%) and targeted therapy (1/25, 4.0%); and non-remission (NR) following ATRA + arsenic compound therapy (4/25, 16%). Four (16.0%) patients were subsequently treated with allogeneic hematopoietic stem cell transplantation (allo-HSCT), two of which remained disease-free at the end of the study period and two of which succumbed to the disease. Secondary bone marrow and CNS relapse occurred in 14 (56.0%) patients and one (4.0%) patient, respectively. ATRA + arsenic compound-based combination therapy was effective in re-inducing morphological remission in relapsed patients with APL with previous exposure to ATRA + arsenic compounds, producing low molecular remission rates and high risk of secondary relapse. Furthermore, investigation of early allo-HSCT is required to determine its potential as a therapeutic

  3. SCB initiator

    DOEpatents

    Bickes Jr., Robert W.; Renlund, Anita M.; Stanton, Philip L.

    1994-11-01

    A detonator for high explosives initiated by mechanical impact includes a cylindrical barrel, a layer of flyer material mechanically covering the barrel at one end, and a semiconductor bridge ignitor including a pair of electrically conductive pads connected by a semiconductor bridge. The bridge is in operational contact with the layer, whereby ignition of said bridge forces a portion of the layer through the barrel to detonate the explosive. Input means are provided for igniting the semiconductor bridge ignitor.

  4. SCB initiator

    DOEpatents

    Bickes, Jr., Robert W.; Renlund, Anita M.; Stanton, Philip L.

    1994-01-01

    A detonator for high explosives initiated by mechanical impact includes a cylindrical barrel, a layer of flyer material mechanically covering the barrel at one end, and a semiconductor bridge ignitor including a pair of electrically conductive pads connected by a semiconductor bridge. The bridge is in operational contact with the layer, whereby ignition of said bridge forces a portion of the layer through the barrel to detonate the explosive. Input means are provided for igniting the semiconductor bridge ignitor.

  5. The DEFECTIVE IN ANTHER DEHISCENCE1 Gene Encodes a Novel Phospholipase A1 Catalyzing the Initial Step of Jasmonic Acid Biosynthesis, Which Synchronizes Pollen Maturation, Anther Dehiscence, and Flower Opening in Arabidopsis

    PubMed Central

    Ishiguro, Sumie; Kawai-Oda, Akiko; Ueda, Junichi; Nishida, Ikuo; Okada, Kiyotaka

    2001-01-01

    The Arabidopsis mutant defective in anther dehiscence1 (dad1) shows defects in anther dehiscence, pollen maturation, and flower opening. The defects were rescued by the exogenous application of jasmonic acid (JA) or linolenic acid, which is consistent with the reduced accumulation of JA in the dad1 flower buds. We identified the DAD1 gene by T-DNA tagging, which is characteristic to a putative N-terminal transit peptide and a conserved motif found in lipase active sites. DAD1 protein expressed in Escherichia coli hydrolyzed phospholipids in an sn-1–specific manner, and DAD1–green fluorescent protein fusion protein expressed in leaf epidermal cells localized predominantly in chloroplasts. These results indicate that the DAD1 protein is a chloroplastic phospholipase A1 that catalyzes the initial step of JA biosynthesis. DAD1 promoter::β-glucuronidase analysis revealed that the expression of DAD1 is restricted in the stamen filaments. A model is presented in which JA synthesized in the filaments regulates the water transport in stamens and petals. PMID:11595796

  6. The eukaryotic translation initiation factor 5, eIF-5, a protein from Zea mays, containing a zinc-finger structure, binds nucleic acids in a zinc-dependent manner.

    PubMed

    López Ribera, I; Ruiz-Avila, L; Puigdomènech, P

    1997-07-18

    A maize cDNA encoding the eukaryotic translation initiation factor 5 (eIF-5) has been isolated from an 8-day-old seedling cDNA library. The 1975 bp cDNA encodes a protein of 451 amino acids, with a predicted molecular weight of 49.04 kDa, and hybridizes to a single sequence in the maize genome. The deduced sequence contains motifs characteristic of proteins belonging to the GPTase superfamily, a zinc finger well conserved in all the protein sequences for eIF-5 reported so far, and a fragment also present in prokaryotic and chloroplast L11 ribosomal protein. Polymer-binding assays have been used to assess the predicted RNA binding property of the protein and to characterize its function. It is shown that the eIF-5-encoded protein binds to single-stranded DNA and to polyuridylic acid and that the binding is dependent on the presence of Zn2+ ions. These results suggest that the zinc-finger structure is involved in the binding of the eIF-5 protein to RNA.

  7. Effects of monomethylarsonic and monomethylarsonous acid on evoked synaptic potentials in hippocampal slices of adult and young rats

    SciTech Connect

    Krueger, Katharina Straub, Heidrun; Hirner, Alfred V.; Hippler, Joerg; Binding, Norbert; Musshoff, Ulrich

    2009-04-01

    Arsenite and its metabolites, dimethylarsinic or dimethylarsinous acid, have previously been shown to disturb synaptic transmission in hippocampal slices of rats (Krueger, K., Gruner, J., Madeja, M., Hartmann, L.M., Hirner, A.V., Binding, N., Mu{beta}hoff, U., 2006a. Blockade and enhancement of glutamate receptor responses in Xenopus oocytes by methylated arsenicals. Arch. Toxicol. 80, 492-501, Krueger, K., Straub, H., Binding, N., Mu{beta}hoff, U., 2006b. Effects of arsenite on long-term potentiation in hippocampal slices from adult and young rats. Toxicol. Lett. 165, 167-173, Krueger, K., Repges, H., Hippler, J., Hartmann, L.M., Hirner, A.V., Straub, H., Binding, N., Mu{beta}hoff, U., 2007. Effects of dimethylarsinic and dimethylarsinous acid on evoked synaptic potentials in hippocampal slices of young and adult rats. Toxicol. Appl. Pharmacol. 225, 40-46). The present experiments investigate, whether the important arsenic metabolites monomethylarsonic acid (MMA{sup V}) and monomethylarsonous acid (MMA{sup III}) also influence the synaptic functions of the hippocampus. In hippocampal slices of young (14-21 days-old) and adult (2-4 months-old) rats, evoked synaptic field potentials from the Schaffer collateral-CA1 synapse were measured under control conditions and during and after 30 and 60 min of application of the arsenic compounds. MMA{sup V} had no effect on the synapse functions neither in slices of adult nor in those from young rats. However, MMA{sup III} strongly influenced the synaptic transmission: it totally depressed the amplitudes of fEPSPs at concentrations of 50 {mu}mol/l (adult rats) and 25 {mu}mol/l (young rats) and LTP amplitudes at concentrations of 25 {mu}mol/l (adult rats) and 10 {mu}mol/l (young rats), respectively. In contrast, application of 1 {mu}mol/l MMA{sup III} led to an enhancement of the LTP amplitude in young rats, which is interpretable by an enhancing effect on NMDA receptors and a lack of the blocking effect on AMPA receptors at

  8. Effects of monomethylarsonic and monomethylarsonous acid on evoked synaptic potentials in hippocampal slices of adult and young rats.

    PubMed

    Krüger, Katharina; Straub, Heidrun; Hirner, Alfred V; Hippler, Jörg; Binding, Norbert; Musshoff, Ulrich

    2009-04-01

    Arsenite and its metabolites, dimethylarsinic or dimethylarsinous acid, have previously been shown to disturb synaptic transmission in hippocampal slices of rats (Krüger, K., Gruner, J., Madeja, M., Hartmann, L.M., Hirner, A.V., Binding, N., Mubetahoff, U., 2006a. Blockade and enhancement of glutamate receptor responses in Xenopus oocytes by methylated arsenicals. Arch. Toxicol. 80, 492-501, Krüger, K., Straub, H., Binding, N., Mubetahoff, U., 2006b. Effects of arsenite on long-term potentiation in hippocampal slices from adult and young rats. Toxicol. Lett. 165, 167-173, Krüger, K., Repges, H., Hippler, J., Hartmann, L.M., Hirner, A.V., Straub, H., Binding, N., Mubetahoff, U., 2007. Effects of dimethylarsinic and dimethylarsinous acid on evoked synaptic potentials in hippocampal slices of young and adult rats. Toxicol. Appl. Pharmacol. 225, 40-46). The present experiments investigate, whether the important arsenic metabolites monomethylarsonic acid (MMA(V)) and monomethylarsonous acid (MMA(III)) also influence the synaptic functions of the hippocampus. In hippocampal slices of young (14-21 days-old) and adult (2-4 months-old) rats, evoked synaptic field potentials from the Schaffer collateral-CA1 synapse were measured under control conditions and during and after 30 and 60 min of application of the arsenic compounds. MMA(V) had no effect on the synapse functions neither in slices of adult nor in those from young rats. However, MMA(III) strongly influenced the synaptic transmission: it totally depressed the amplitudes of fEPSPs at concentrations of 50 micromol/l (adult rats) and 25 micromol/l (young rats) and LTP amplitudes at concentrations of 25 micromol/l (adult rats) and 10 micromol/l (young rats), respectively. In contrast, application of 1 micromol/l MMA(III) led to an enhancement of the LTP amplitude in young rats, which is interpretable by an enhancing effect on NMDA receptors and a lack of the blocking effect on AMPA receptors at this concentration (Kr

  9. A region rich in aspartic acid, arginine, tyrosine, and glycine (DRYG) mediates eukaryotic initiation factor 4B (eIF4B) self-association and interaction with eIF3.

    PubMed Central

    Méthot, N; Song, M S; Sonenberg, N

    1996-01-01

    The binding of mRNA to the ribosome is mediated by eukaryotic initiation factors eukaryotic initiation factor 4F (eIF4F), eIF4B, eIF4A, and eIF3, eIF4F binds to the mRNA cap structure and, in combination with eIF4B, is believed to unwind the secondary structure in the 5' untranslated region to facilitate ribosome binding. eIF3 associates with the 40S ribosomal subunit prior to mRNA binding. eIF4B copurifies with eIF3 and eIF4F through several purification steps, suggesting the involvement of a multisubunit complex during translation initiation. To understand the mechanism by which eIF4B promotes 40S ribosome binding to the mRNA, we studied its interactions with partner proteins by using a filter overlay (protein-protein [far Western]) assay and the two-hybrid system. In this report, we show that eIF4B self-associates and also interacts directly with the p170 subunit of eIF3. A region rich in aspartic acid, arginine, tyrosine, and glycine, termed the DRYG domain, is sufficient for self-association of eIF4B, both in vitro and in vivo, and for interaction with the p170 subunit of eIF3. These experiments suggest that eIF4B participates in mRNA-ribosome binding by acting as an intermediary between the mRNA and eIF3, via a direct interaction with the p170 subunit of eIF3. PMID:8816444

  10. Cetuximab in combination with irinotecan/5-fluorouracil/folinic acid (FOLFIRI) in the initial treatment of metastatic colorectal cancer: a multicentre two-part phase I/II study

    PubMed Central

    2009-01-01

    Background This study was designed to investigate the efficacy and safety of the epidermal growth factor receptor (EGFR) inhibitor cetuximab combined with irinotecan, folinic acid (FA) and two different doses of infusional 5-fluorouracil (5-FU) in the first-line treatment of EGFR-detectable metastatic colorectal cancer. Methods The 5-FU dose was selected on the basis of dose-limiting toxicities (DLTs) during part I of the study. Patients received cetuximab (400 mg/m2 initial dose and 250 mg/m2/week thereafter) and every 2 weeks irinotecan (180 mg/m2), FA (400 mg/m2) and 5-FU (either low dose [LD], 300 mg/m2 bolus plus 2,000 mg/m2 46-hour infusion, n = 7; or, high-dose [HD], 400 mg/m2 bolus plus 2,400 mg/m2; n = 45). Results Only two DLTs occurred in the HD group, and HD 5-FU was selected for use in part II. Apart from rash, commonly observed grade 3/4 adverse events such as leucopenia, diarrhoea, vomiting and asthenia occurred within the expected range for FOLFIRI. Among 52 patients, the overall response rate was 48%. Median progression-free survival (PFS) was 8.6 months (counting all reported progressions) and the median overall survival was 22.4 months. Treatment facilitated the resection of initially unresectable metastases in fourteen patients (27%): of these, 10 patients (71%) had no residual tumour after surgery, and these resections hindered the estimation of PFS. Conclusion The combination of cetuximab and FOLFIRI was active and well tolerated in this setting. Initially unresectable metastases became resectable in one-quarter of patients, with a high number of complete resections, and these promising results formed the basis for the investigation of FOLFIRI with and without cetuximab in the phase III CRYSTAL trial. PMID:19366444

  11. Openness initiative

    SciTech Connect

    Duncan, S.S.

    1995-12-31

    Although antinuclear campaigns seem to be effective, public communication and education efforts on low-level radioactive waste have mixed results. Attempts at public information programs on low-level radioactive waste still focus on influencing public opinion. A question then is: {open_quotes}Is it preferable to have a program focus on public education that will empower individuals to make informed decisions rather than trying to influence them in their decisions?{close_quotes} To address this question, a case study with both quantitative and qualitative data will be used. The Ohio Low-Level Radioactive Waste Education Program has a goal to provide people with information they want/need to make their own decisions. The program initiated its efforts by conducting a statewide survey to determine information needed by people and where they turned for that information. This presentation reports data from the survey and then explores the program development process in which programs were designed and presented using the information. Pre and post data from the programs reveal attitude and knowledge shifts.

  12. Microdrill Initiative - Initial Market Evaluation

    SciTech Connect

    Spears & Associates, Inc

    2003-07-01

    The U.S. Department of Energy (DOE) is launching a major research and development initiative to create a small, fast, inexpensive and environmentally friendly rig for drilling 5000 feet boreholes to investigate potential oil and gas reservoirs. DOE wishes to get input from petroleum industry operators, service companies and equipment suppliers on the operation and application of this coiled-tubing-based drilling unit. To that end, DOE has asked Spears & Associates, Inc. (SAI) to prepare a special state-of-the-market report and assist during a DOE-sponsored project-scoping workshop in Albuquerque near the end of April 2003. The scope of the project is four-fold: (1) Evaluate the history, status and future of demand for very small bore-hole drilling; (2) Measure the market for coiled tubing drilling and describe the state-of-the-art; (3) Identify companies and individuals who should have an interest in micro drilling and invite them to the DOE workshop; and (4) Participate in 3 concurrent workshop sessions, record and evaluate participant comments and report workshop conclusions.

  13. Acid clusters

    SciTech Connect

    Keesee, R.G.; Castleman, A.W. Jr.

    1986-04-01

    Molecular clusters can be considered to be the smallest size range of an aerosol particle size distribution. Nucleation from the gas phase to particles or droplets involves the formation of clusters in the initial stages. Consequently, knowledge of the properties and formation of clusters containing acids contribute to an understanding of acid rain. This paper presents an overview of results obtained in the laboratory on the formation and stability of both neutral and ionized acid clusters. With free jet expansion techniques, the authors have produced clusters of aqueous nitric acid, aqueous hydrochloric acid, aqueous sulfuric acid, acetic acid and aqueous sulfur dioxide. For analogy to buffering, the formation of clusters containing ammonia have also been examined. These have included ammonia with aqueous nitric acid, hydrogen sulfide and sulfur dioxide. The basic experiment involves expansion of vapor through a nozzle, collimation of the jet with a skimmer to form a well-directed molecular beam, and detection of clusters via electron impact ionization and mass spectrometry. Some variations include the introduction of a reactive gas into vacuum near the expansion as described elsewhere and the implementation of an electrostatic quadrupolar field to examine the polarity of the neutral clusters.

  14. Demethylation of Methylated Arsenic Species during Generation of Arsanes with Tetrahydridoborate(1-) in Acidic Media.

    PubMed

    Marschner, Karel; Musil, Stanislav; Dědina, Jiří

    2016-06-21

    Demethylation during generation of volatile hydrides (HG), i.e. formation of noncorresponding arsanes from monomethylarsonic acid (MAs(V)), dimethylarsinic acid (DMAs(V)), and trimethylarsine oxide (TMAs(V)O) by the reaction of sodium tetrahydridoborate(1-) (THB) with different acids under analytical conditions, was investigated and characterized. Pronounced demethylation of MAs(V), DMAs(V), and TMAs(V)O was found during the reaction of THB with HCl, H2SO4, and HClO4, while HG from CH3COOH or TRIS buffer after prereduction with l-cysteine resulted in the formation of only the corresponding hydrides. In the case of HNO3 formation of corresponding hydrides was preserved for MAs(V) and DMAs(V) but not for TMAs(V)O. The extent of demethylation strongly depends on concentration of the acid and THB. It can be strongly suppressed in HCl medium by partial hydrolysis of THB with optimal concentration of acid before it reacts with MAs(V), DMAs(V), or TMAs(V)O. It appears that the demethylation is due to the action of specific hydrolytic products of THB (most probably by the first and second one).

  15. Tuning selectivity of anionic cyclizations: competition between 5-exo and 6-endo-dig closures of hydrazides of o-acetylenyl benzoic acids and based-catalyzed fragmentation/recyclization of the initial 5-exo-dig products.

    PubMed

    Vasilevsky, Sergey F; Mikhailovskaya, Tat'yana F; Mamatyuk, Victor I; Salnikov, Georgy E; Bogdanchikov, Georgy A; Manoharan, Mariappan; Alabugin, Igor V

    2009-11-06

    Depending on the reaction conditions and the nature of substituents at the triple bond, anionic cyclizations of hydrazides of o-acetylenyl benzoic acids can be selectively directed along three alternative paths, each of which provides efficient access to a different class of nitrogen heterocycles. The competition between 5-exo and 6-endo cyclizations of the "internal" nitrogen nucleophile is controlled by the nature of alkyne substituents under the kinetic control conditions. In the presence of KOH, the initially formed 5-exo products undergo a new rearrangement that involves a ring-opening followed by recyclization to the formal 6-exo-products and rendered irreversible by a prototropic isomerization. DFT computations provide insight into the nature of factors controlling relative rates of 5-exo, 6-endo, and 6-exo cyclization paths, ascertain the feasibility of direct 6-exo closure and relative stability for the anionic precursor for this process, provide, for the first time, the benchmark data for several classes of anionic nitrogen cyclizations, and dissect stereoelectronic effects controlling relative stability of cyclic anionic intermediates and influencing reaction stereoselectivity. We show that the stability gain due transformation of a weak pi-bond into a stronger sigma-bond (the usual driving force for the cyclizations of alkynes) is offset in this case by the transformation of a stable nitrogen anion into an inherently less stable carbanionic center. As a result, the cyclizations are much more sensitive to external conditions and substituents than similar cyclizations of neutral species. However, the exothermicity of such anionic cyclizations is increased dramatically upon prototropic isomerization of the initially formed carbanions into the more stable N-anions. Such tautomerizations are likely to play the key role in driving such cyclizations to completion but may also prevent future applications of such processes as the first step in domino cyclization

  16. Preparation of magnetic indole-3-acetic acid imprinted polymer beads with 4-vinylpyridine and β-cyclodextrin as binary monomer via microwave heating initiated polymerization and their application to trace analysis of auxins in plant tissues.

    PubMed

    Zhang, Yi; Li, Yuanwen; Hu, Yuling; Li, Gongke; Chen, Yueqin

    2010-11-19

    Auxin is a crucial phytohormone for precise control of growth and development of plants. Due to its low concentration in plant tissues which are rich in interfering substances, the accurate determination of auxins remains a challenge. In this paper, a new strategy for isolation and enrichment of auxins from plant tissues was obtained by the magnetic molecularly imprinted polymer (mag-MIP) beads, which were prepared by microwave heating initiated suspension polymerization using indole-3-acetic acid (IAA) as template. In order to obtain higher selective recognition cavities, an enhanced imprinting method based on binary functional monomers, 4-vinylpyridine (4-VP) and β-cyclodextrin (β-CD), was adopted for IAA imprinting. The morphological and magnetic characteristics of the mag-MIP beads were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy and vibrating sample magnetometry. A majority of resultant beads were within the size range of 80-150μm. Porous surface morphology and good magnetic property were observed. Furthermore, the mag-MIP beads fabricated with 4-VP and β-CD as binary functional monomers exhibited improved recognition ability to IAA, as compared with the mag-MIP beads prepared with the individual monomer separately. Competitive rebinding experiment results revealed that the mag-MIP beads exhibited a higher specific recognition for the template than the non-imprinted polymer (mag-NIP) beads. An extraction method by mag-MIP beads coupled with high performance liquid chromatography (HPLC) was developed for determination of IAA and indole-3-butyric acid (IBA) in plant tissues. Linear ranges for IAA and IBA were in the range of 7.00-100.0μgL(-1) and 10.0-100.0μgL(-1), and the detection limits were 3.9 and 7.4μgL(-1), respectively. The analytical performance was also estimated by seedlings or immature embryos samples from three different plant tissues, pea, rice and wheat. Recoveries were in the range of 70

  17. Charged Amino Acid Residues 997–1000 of Human Apolipoprotein B100 Are Critical for the Initiation of Lipoprotein Assembly and the Formation of a Stable Lipidated Primordial Particle in McA-RH7777 Cells*

    PubMed Central

    Manchekar, Medha; Richardson, Paul E.; Sun, Zhihuan; Liu, Yanwen; Segrest, Jere P.; Dashti, Nassrin

    2008-01-01

    We previously demonstrated that a portion, or perhaps all, of the residues between 931 and 1000 of apolipoprotein (apo) B100 are required for the initiation of apoB-containing particle assembly. Based on our structural model of the first 1000 residues of apoB (designated as apoB:1000), we hypothesized that this domain folds into a three-sided lipovitellin-like “lipid pocket” via a hairpin-bridge mechanism. We proposed that salt bridges are formed between four tandem charged residues 717–720 in the turn of the hairpin bridge and four tandem complementary residues 997–1000 located at the C-terminal end of the model. To identify the specific motif within residues 931 and 1000 that is critical for apoB particle assembly, apoB:956 and apoB:986 were produced. To test the hairpin-bridge hypothesis, the following mutations were made: 1) residues 997–1000 deletion (apoB:996), 2) residues 717–720 deletion (apoB:1000Δ717–720), and 3) substitution of charged residues 997–1000 with alanines (apoB:996 + 4Ala). Characterization of particles secreted by stable transformants of McA-RH7777 cells demonstrated the following. 1) ApoB:956 did not form stable particles and was secreted as large lipid-rich aggregates. 2) ApoB:986 formed both a lipidated particle that was denser than HDL3 and large lipid-rich aggregates. 3) Compared with wild-type apoB:1000, apoB:1000Δ717–720 displayed the following: (i) significantly diminished capacity to form intact lipidated particles and (ii) increased propensity to form large lipid-rich aggregates. 4) In striking contrast to wild-type apoB:1000, (i) apoB:996 and apoB:996 + 4Ala were highly susceptible to intracellular degradation, (ii) only a small proportion of the secreted proteins formed stable HDL3-like lipoproteins, and (iii) a majority of the secreted proteins formed large lipid-rich aggregates. We conclude that the first 1000 amino acid residues of human apoB100 are required for the initiation of nascent apo

  18. Influence of humic acid on the removal of arsenate and arsenic by ferric chloride: effects of pH, As/Fe ratio, initial As concentration, and co-existing solutes.

    PubMed

    Kong, Yanli; Kang, Jing; Shen, Jimin; Chen, Zhonglin; Fan, Leitao

    2017-01-01

    The influence of humic acid (HA) on the removal of arsenic by FeCl3 was systematically studied in this paper. Jar tests were performed to investigate the influence on arsenic during FeCl3 coagulation of the pH adjusting method, the initial As/Fe ratio, the equilibrium As concentration, and co-occurring anions and cations. Compared with results in HA-free systems, the removal trends of arsenic in HA solutions were quite different. It was found that As(V) removal was higher at low equilibrium concentration, yet the opposite was true for As(III) removal. The presence of HA influenced the effective number of active sites for arsenic removal by FeCl3 flocculation. In addition, in the presence of HA, the impacts of co-existing solutions on arsenic removal were also different from that of an HA-free system. This study examined the influence of co-occurring anions, such as phosphate, sulfate, and silicate on arsenic removal, depending on their ability to compete for sorption sites and to hinder or facilitate the aggregation of ferric hydroxide flocs. The presence of Ca(2+) or Cd(2+) significantly increased arsenic removal at higher pH. Low concentrations of dissolved HA and high concentrations of colloid affected the adsorption of arsenic onto iron oxide. The influence of HA on the adsorption of arsenic onto iron oxide primarily depended on the relative content of the dissolved and mineral combination states of HA and the interface combination forms.

  19. The nucleic acid-binding zinc finger protein of potato virus M is translated by internal initiation as well as by ribosomal frameshifting involving a shifty stop codon and a novel mechanism of P-site slippage.

    PubMed

    Gramstat, A; Prüfer, D; Rohde, W

    1994-09-25

    The genes for the capsid protein CP and the nucleic acid-binding 12K protein (pr12) of potato virus M (PVM) constitute the 3' terminal gene cluster of the PVM RNA genome. Both proteins are presumably translated from a single subgenomic RNA. We have identified two translational strategies operating in pr12 gene expression. Internal initiation at the first and the second AUG codon of the pr12 coding sequence results in the synthesis of the 12K protein. In addition the protein is produced as a CP/12K transframe protein by ribosomal frameshifting. For these studies parts of the CP and pr12 coding sequences including the putative frameshift region were introduced into an internal position of the beta-glucuronidase gene. Mutational analyses in conjunction with in vitro translation experiments identified a homopolymeric string of four adenosine nucleotides which together with a 3' flanking UGA stop codon were required for efficient frameshifting. The signal AAAAUGA is the first frameshift signal with a shifty stop codon to be analyzed in the eukaryotic system. Substitution of the four consecutive adenosine nucleotides by UUUU increased the efficiency of frameshifting, while substitution by GGGG or CCCC dramatically reduced the synthesis of the transframe protein. Also, UAA and UAG could replace the opal stop codon without effect on the frameshifting event, but mutation of UGA to the sense codon UGG inhibited transframe protein formation. These findings suggest that the mechanism of ribosomal frameshifting at the PVM signal is different from the one described by the 'simultaneous slippage' model in that only the string of four adenosine nucleotides represents the slippery sequence involved in a -1 P-site slippage.

  20. Evaluation of lactic acid as an initial and secondary subprimal intervention for Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli, and a nonpathogenic E. coli surrogate for E. coli O157:H7.

    PubMed

    Pittman, C I; Geornaras, I; Woerner, D R; Nightingale, K K; Sofos, J N; Goodridge, L; Belk, K E

    2012-09-01

    Lactic acid can reduce microbial contamination on beef carcass surfaces when used as a food safety intervention, but effectiveness when applied to the surface of chilled beef subprimal sections is not well documented. Studies characterizing bacterial reduction on subprimals after lactic acid treatment would be useful for validations of hazard analysis critical control point (HACCP) systems. The objective of this study was to validate initial use of lactic acid as a subprimal intervention during beef fabrication followed by a secondary application to vacuum-packaged product that was applied at industry operating parameters. Chilled beef subprimal sections (100 cm(2)) were either left uninoculated or were inoculated with 6 log CFU/cm(2) of a 5-strain mixture of Escherichia coli O157:H7, a 12-strain mixture of non-O157 Shiga toxin-producing E. coli (STEC), or a 5-strain mixture of nonpathogenic (biotype I) E. coli that are considered surrogates for E. coli O157:H7. Uninoculated and inoculated subprimal sections received only an initial or an initial and a second "rework" application of lactic acid in a custombuilt spray cabinet at 1 of 16 application parameters. After the initial spray, total inoculum counts were reduced from 6.0 log CFU/cm(2) to 3.6, 4.4, and 4.4 log CFU/cm(2) for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. After the second (rework) application, total inoculum counts were 2.6, 3.2, and 3.6 log CFU/cm(2) for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. Both the initial and secondary lactic acid treatments effectively reduced counts of pathogenic and nonpathogenic strains of E. coli and natural microflora on beef subprimals. These data will be useful to the meat industry as part of the HACCP validation process.

  1. Arsenic accumulation and speciation in rice grown in arsanilic acid-elevated paddy soil.

    PubMed

    Geng, Anjing; Wang, Xu; Wu, Lishu; Wang, Fuhua; Chen, Yan; Yang, Hui; Zhang, Zhan; Zhao, Xiaoli

    2017-03-01

    P-arsanilic acid (AsA) is a emerging but less concerned contaminant used in animal feeding operations, for it can be degraded to more toxic metabolites after being excreted by animals. Rice is the staple food in many parts of the world, and also more efficient in accumulating arsenic (As) compared to other cereals. However, the uptake and transformation of AsA by rice is unclear. This study aimed to evaluate the potential risk of using AsA as a feed additive and using the AsA contaminated animal manure as a fertilizer. Five rice cultivars were grown in soil containing 100mg AsA/kg soil, after harvest, As species and their concentrations in different tissues were determined. Total As concentration of the hybrid rice cultivar was more than conventional rice cultivars for whole rice plant. For rice organs, the highest As concentration was found in roots. AsA could be absorbed by rice, partly degraded and converted to arsenite, monomethylarsonic acid, dimethylarsinic acid, arsenate. The number of As species and their concentrations in each cultivar were related to their genotypes. The soil containing 100mg AsA/kg or more is unsuitable for growing rice. The use of AsA and the disposal of animal manure requires detailed attention.

  2. Determination of monomethylarsonous acid, a key arsenic methylation intermediate, in human urine.

    PubMed Central

    Le, X C; Ma, M; Cullen, W R; Aposhian, H V; Lu, X; Zheng, B

    2000-01-01

    In this study we report on the finding of monomethylarsonous acid [MMA(III)] in human urine. This newly identified arsenic species is a key intermediate in the metabolic pathway of arsenic biomethylation, which involves stepwise reduction of pentavalent to trivalent arsenic species followed by oxidative addition of a methyl group. Arsenic speciation was carried out using ion-pair chromatographic separation of arsenic compounds with hydride generation atomic fluorescence spectrometry detection. Speciation of the inorganic arsenite [As(III)], inorganic arsenate [As(V)], monomethylarsonic acid [MMA(V)], dimethylarsinic acid [DMA(V)], and MMA(III) in a urine sample was complete in 5 min. Urine samples collected from humans before and after a single oral administration of 300 mg sodium 2,3-dimercapto-1-propane sulfonate (DMPS) were analyzed for arsenic species. MMA(III) was found in 51 out of 123 urine samples collected from 41 people in inner Mongolia 0-6 hr after the administration of DMPS. MMA(III )in urine samples did not arise from the reduction of MMA(V) by DMPS. DMPS probably assisted the release of MMA(III) that was formed in the body. Along with the presence of MMA(III), there was an increase in the relative concentration of MMA(V) and a decrease in DMA(V) in the urine samples collected after the DMPS ingestion. PMID:11102289

  3. DEVELOPMENT OF EXPLOSIVES AND INITIATORS FOR SPECIAL WARFARE OPERATIONS.

    DTIC Science & Technology

    FUZES(ORDNANCE), FUZES(ORDNANCE), DETONATORS, DETONATING CORD, PREPARATION, CORDAGE, PHENOLS, NITRATES, WARFARE, EXPLOSIONS, DEMOLITION, MERCURY COMPOUNDS, NITRIC ACID, ALCOHOLS, EXPLOSIVES INITIATORS.

  4. The Plus 50 Initiative Evaluation: Initiative Impact

    ERIC Educational Resources Information Center

    American Association of Community Colleges (NJ1), 2012

    2012-01-01

    The American Association of Community Colleges (AACC), with funding from The Atlantic Philanthropies, created the Plus 50 Initiative (2008-2012). This initiative was designed to build the capacity of community colleges nationwide to develop programming that engages the plus 50 learner. This report contains: (1) An overview of the Plus 50…

  5. Initialized Fractional Calculus

    NASA Technical Reports Server (NTRS)

    Lorenzo, Carl F.; Hartley, Tom T.

    2000-01-01

    This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.

  6. Immediate acid-suppressing effects of ranitidine hydrochloride and rabeprazole sodium following initial administration and reintroduction: A randomized, cross-over study using wireless pH monitoring capsules.

    PubMed

    Ono, Shouko; Kato, Mototsugu; Ono, Yuji; Imai, Aki; Yoshida, Takeshi; Shimizu, Yuichi; Asaka, Masahiro

    2009-04-01

    Histamine 2 receptor antagonists and proton-pump inhibitors, drugs that are widely used for the treatment of acid-related diseases, have different clinical characteristics. The objective of this study was to compare the acid-suppressing effects of ranitidine hydrochloride and those of rabeprazole sodium at the first administration and re-administration after withdrawal. The study was designed as an open-label, randomized, two-way cross-over trial. Seven Helicobacter pylori-negative healthy volunteers were enrolled in this study. Ranitidine hydrochloride (300 mg/day) or rabeprazole sodium (20 mg/day) was administered from days 1 to 7 and from days 11 to 13. The percentage of time with gastric pH < 4 and the median gastric pH were evaluated for 15 consecutive days by a Bravo capsule fixed to the stomach. On day 1, there was no significant difference between the acid-suppressing effects of the two drugs (ranitidine vs rabeprazole: not significant). Although rabeprazole sodium maintained a potent and stable effect from days 2 to 7 (ranitidine vs rabeprazole: P < 0.05), the effect of ranitidine hydrochloride was attenuated after day 4. In addition, the effect of ranitidine hydrochloride at re-administration was attenuated (days 11, 12, and 13 vs pre-administration: not significant). In view of our observations, we expect symptoms associated with gastric acidity to be more adequately controlled with rabeprazole sodium in the short term when compared to ranitidine hydrochloride.

  7. Allylic alcohol transposition by ortho ester-initiated carbonate extension. synthesis of the vasodilator 11(R),12(S),15(S)-trihydroxyeicosa- 5(Z),8(Z),13(E)-trienoic acid.

    PubMed

    Conrow, Raymond E

    2006-05-25

    [reaction: see text] The title compound 1 was obtained via methyl ester 2, which was synthesized in four steps from an isomeric 11,14,15-triol ester 5. In the key step, Boc orthoformate 9 was treated with TMS triflate to initiate intramolecular nucleophilic substitution with allylic transposition, forming cyclic carbonates 10 and 11.

  8. Dioxin Exposure Initiative

    EPA Pesticide Factsheets

    The Dioxin Exposure Initiative (DEI) is no longer active. This page contains a summary of the dioxin exposure initiative with illustrations, contact and background information.Originally supported by scientist Matthew Lorber, who retired in Mar 2017.

  9. Initiation of vascular development.

    PubMed

    Ohashi-Ito, Kyoko; Fukuda, Hiroo

    2014-06-01

    The initiation of vascular development occurs during embryogenesis and the development of lateral organs, such as lateral roots and leaves. Understanding the mechanism underlying the initiation of vascular development has been an important goal of plant biologists. Auxin flow is a crucial factor involved in the initiation of vascular development. In addition, recent studies have identified key factors that regulate the establishment of vascular initial cells in embryos and roots. In this review, we summarize the recent findings in this field and discuss the initiation of vascular development.

  10. Initial Events in Bacterial Transcription Initiation

    PubMed Central

    Ruff, Emily F.; Record, M. Thomas; Artsimovitch, Irina

    2015-01-01

    Transcription initiation is a highly regulated step of gene expression. Here, we discuss the series of large conformational changes set in motion by initial specific binding of bacterial RNA polymerase (RNAP) to promoter DNA and their relevance for regulation. Bending and wrapping of the upstream duplex facilitates bending of the downstream duplex into the active site cleft, nucleating opening of 13 bp in the cleft. The rate-determining opening step, driven by binding free energy, forms an unstable open complex, probably with the template strand in the active site. At some promoters, this initial open complex is greatly stabilized by rearrangements of the discriminator region between the −10 element and +1 base of the nontemplate strand and of mobile in-cleft and downstream elements of RNAP. The rate of open complex formation is regulated by effects on the rapidly-reversible steps preceding DNA opening, while open complex lifetime is regulated by effects on the stabilization of the initial open complex. Intrinsic DNA opening-closing appears less regulated. This noncovalent mechanism and its regulation exhibit many analogies to mechanisms of enzyme catalysis. PMID:26023916

  11. Cluster-Randomized Non-Inferiority Trial to Compare Supplement Consumption and Adherence to Different Dosing Regimens for Antenatal Calcium and Iron-Folic Acid Supplementation to Prevent Preeclampsia and Anaemia: Rationale and Design of the Micronutrient Initiative Study.

    PubMed

    Omotayo, Moshood O; Dickin, Katherine L; Chapleau, Gina M; Martin, Stephanie L; Chang, Christopher; Mwanga, Erick O; Kung'u, Jacqueline K; Stoltzfus, Rebecca J

    2015-11-17

    To prevent pre-eclampsia in populations with insufficient dietary calcium (Ca) intake, the World Health Organisation (WHO) recommends routine Ca supplementation during antenatal care (ANC). WHO guidelines suggest a complex dosing regimen, requiring as many as 5 pill-taking events per day when combined with iron and folic acid (IFA) supplements. Poor adherence may undermine public health effectiveness, so simpler regimens may be preferable. This trial will compare the effect of the WHO-recommended (higher-dose) regimen vs. a simpler, lower-dose regimen on supplement consumption and pill-taking behaviours in Kenyan ANC clients. This is a parallel, non-inferiority, cluster-randomized trial; we examined 16 primary care health facilities in Kenya, 1047 pregnant women between 16-30 weeks gestational age. Higher-dose regimen: 1.5 g elemental calcium in 3 separate doses (500 mg Ca/pill) and IFA (60 mg Fe + 400 µg folic acid) taken with evening dose. Lower-dose regimen: 1.0 g calcium in 2 separate doses (500 mg Ca/pill) with IFA taken as above. Primary outcome is Ca pills consumed per day, measured by pill counts. Secondary outcomes include IFA pills consumed per day, client knowledge, motivation, social support, and satisfaction, measured at 4 to 10 weeks post-enrolment. Unit of randomization is the healthcare facility; unit of analysis is individual client. Intent-to-treat analysis will be implemented with multi-level models to account for clustering. If pregnant women prescribed lower doses of Ca ingest as many pills as women prescribed the WHO-recommended regimen, developing a lower-dose recommendation for antenatal Ca and IFA supplementation programs could save resources. Significance for public healthPre-eclampsia is a leading cause of maternal mortality. Based on clinical evidence of significant reduction in risk of pre-eclampsia, the WHO recommends including calcium (Ca) supplementation in antenatal care services in settings with inadequate dietary Ca intakes. A

  12. Radioenzymatic assay for quinolinic acid

    SciTech Connect

    Foster, A.C.; Okuno, E.; Brougher, D.S.; Schwarcz, R.

    1986-10-01

    A new and rapid method for the determination of the excitotoxic tryptophan metabolite quinolinic acid is based on its enzymatic conversion to nicotinic acid mononucleotide and, in a second step utilizing (/sup 3/H)ATP, further to (/sup 3/H) deamido-NAD. Specificity of the assay is assured by using a highly purified preparation of the specific quinolinic acid-catabolizing enzyme, quinolinic acid phosphoribosyltransferase, in the initial step. The limit of sensitivity was found to be 2.5 pmol of quinolinic acid, sufficient to conveniently determine quinolinic acid levels in small volumes of human urine and blood plasma.

  13. Monitoring Abortive Initiation

    PubMed Central

    Hsu, Lilian M.

    2009-01-01

    Abortive initiation, when first discovered, was an enigmatic phenomenon, but fully three decades hence, it has been shown to be an integral step in the transcript initiation process intimately tied to the promoter escape reaction undergone by RNA polymerase at the initiation-elongation transition. A detailed understanding of abortive initiation-promoter escape has brought within reach a full description of the transcription initiation mechanism. This enormous progress was the result of convergent biochemical, genetic, and biophysical investigations propelled by parallel advances in quantitation technology. This chapter discusses the knowledge gained through the biochemical approach and a high-resolution method that yields quantitative and qualitative information regarding abortive initiation-promoter escape at a promoter. PMID:18948204

  14. Progress in Initiator Modeling

    SciTech Connect

    Hrousis, C A; Christensen, J S

    2009-05-04

    There is great interest in applying magnetohydrodynamic (MHD) simulation techniques to the designs of electrical high explosive (HE) initiators, for the purpose of better understanding a design's sensitivities, optimizing its performance, and/or predicting its useful lifetime. Two MHD-capable LLNL codes, CALE and ALE3D, are being used to simulate the process of ohmic heating, vaporization, and plasma formation in the bridge of an initiator, be it an exploding bridgewire (EBW), exploding bridgefoil (EBF) or slapper type initiator. The initiation of the HE is simulated using Tarver Ignition & Growth reactive flow models. 1-D, 2-D and 3-D models have been constructed and studied. The models provide some intuitive explanation of the initiation process and are useful for evaluating the potential impact of identified aging mechanisms (such as the growth of intermetallic compounds or powder sintering). The end product of this work is a simulation capability for evaluating margin in proposed, modified or aged initiation system designs.

  15. Exploring the in vitro formation of trimethylarsine sulfide from dimethylthioarsinic acid in anaerobic microflora of mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS

    SciTech Connect

    Kubachka, Kevin M.; Kohan, Michael C.; Herbin-Davis, Karen; Creed, John T. Thomas, David J.

    2009-09-01

    Although metabolism of arsenicals to form methylated oxoarsenical species has been extensively studied, less is known about the formation of thiolated arsenical species that have recently been detected as urinary metabolites. Indeed, their presence suggests that the metabolism of ingested arsenic is more complex than previously thought. Recent reports have shown that thiolated arsenicals can be produced by the anaerobic microflora of the mouse cecum, suggesting that metabolism prior to systemic absorption may be a significant determinant of the pattern and extent of exposure to various arsenic-containing species. Here, we examined the metabolism of {sup 34}S labeled dimethylthioarsinic acid ({sup 34}S-DMTA{sup V}) by the anaerobic microflora of the mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS/MS to monitor for the presence of various oxo- and thioarsenicals. The use of isotopically enriched {sup 34}S-DMTA{sup V} made it possible to differentiate among potential metabolic pathways for production of the trimethylarsine sulfide (TMAS{sup V}). Upon in vitro incubation in an assay containing anaerobic microflora of mouse cecum, {sup 34}S-DMTA{sup V} underwent several transformations. Labile {sup 34}S was exchanged with more abundant {sup 32}S to produce {sup 32}S-DMTA{sup V}, a thiol group was added to yield DMDTA{sup V}, and a methyl group was added to yield {sup 34}S-TMAS{sup V}. Because incubation of {sup 34}S-DMTA{sup V} resulted in the formation of {sup 34}S-TMAS{sup V}, the pathway for its formation must preserve the arsenic-sulfur bond. The alternative metabolic pathway postulated for formation of TMAS{sup V} from dimethylarsinic acid (DMA{sup V}) would proceed via a dimethylarsinous acid (DMA{sup III}) intermediate and would necessitate the loss of {sup 34}S label. Structural confirmation of the metabolic product was achieved using HPLC-ESI-MS/MS. The data presented support the direct methylation of DMTA{sup V} to TMAS{sup V}. Additionally, the detection of

  16. [Lipid synthesis by an acidic acid tolerant Rhodotorula glutinis].

    PubMed

    Lin, Zhangnan; Liu, Hongjuan; Zhang, Jian'an; Wang, Gehua

    2016-03-01

    Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis.

  17. Cluster-Randomized Non-Inferiority Trial to Compare Supplement Consumption and Adherence to Different Dosing Regimens for Antenatal Calcium and Iron-Folic Acid Supplementation to Prevent Preeclampsia and Anaemia: Rationale and Design of the Micronutrient Initiative Study

    PubMed Central

    Dickin, Katherine L; Chapleau, Gina M.; Martin, Stephanie L.; Chang, Christopher; Mwanga, Erick O.; Kung’u, Jacqueline K.; Stoltzfus, Rebecca J.

    2015-01-01

    Background: To prevent pre-eclampsia in populations with insufficient dietary calcium (Ca) intake, the World Health Organisation (WHO) recommends routine Ca supplementation during antenatal care (ANC). WHO guidelines suggest a complex dosing regimen, requiring as many as 5 pill-taking events per day when combined with iron and folic acid (IFA) supplements. Poor adherence may undermine public health effectiveness, so simpler regimens may be preferable. This trial will compare the effect of the WHO-recommended (higher-dose) regimen vs. a simpler, lower-dose regimen on supplement consumption and pill-taking behaviours in Kenyan ANC clients. Design and methods: This is a parallel, non-inferiority, cluster-randomized trial; we examined 16 primary care health facilities in Kenya, 1047 pregnant women between 16-30 weeks gestational age. Higher-dose regimen: 1.5 g elemental calcium in 3 separate doses (500 mg Ca/pill) and IFA (60 mg Fe + 400 µg folic acid) taken with evening dose. Lower-dose regimen: 1.0 g calcium in 2 separate doses (500 mg Ca/pill) with IFA taken as above. Measurements: Primary outcome is Ca pills consumed per day, measured by pill counts. Secondary outcomes include IFA pills consumed per day, client knowledge, motivation, social support, and satisfaction, measured at 4 to 10 weeks post-enrolment. Statistical analyses: Unit of randomization is the healthcare facility; unit of analysis is individual client. Intent-to-treat analysis will be implemented with multi-level models to account for clustering. Expected public health impact: If pregnant women prescribed lower doses of Ca ingest as many pills as women prescribed the WHO-recommended regimen, developing a lower-dose recommendation for antenatal Ca and IFA supplementation programs could save resources. Significance for public health Pre-eclampsia is a leading cause of maternal mortality. Based on clinical evidence of significant reduction in risk of pre-eclampsia, the WHO recommends including calcium

  18. Prioritizing Scientific Initiatives.

    ERIC Educational Resources Information Center

    Bahcall, John N.

    1991-01-01

    Discussed is the way in which a limited number of astronomy research initiatives were chosen and prioritized based on a consensus of members from the Astronomy and Astrophysics Survey Committee. A list of recommended equipment initiatives and estimated costs is provided. (KR)

  19. Prioritizing Scientific Initiatives.

    ERIC Educational Resources Information Center

    Bahcall, John N.

    1991-01-01

    Discussed is the way in which a limited number of astronomy research initiatives were chosen and prioritized based on a consensus of members from the Astronomy and Astrophysics Survey Committee. A list of recommended equipment initiatives and estimated costs is provided. (KR)

  20. The Fostering Hope Initiative

    ERIC Educational Resources Information Center

    Rider, Steven; Winters, Katie; Dean, Joyce; Seymour, Jim

    2014-01-01

    The Fostering Hope Initiative is a neighborhood-based Collective Impact initiative that promotes optimum child and youth development by supporting vulnerable families, encouraging connections between neighbors, strengthening systems to ensure collective impact, and advocating for family-friendly public policy. This article describes the…

  1. Community Marriage Initiatives

    ERIC Educational Resources Information Center

    Doherty, William J.; Anderson, Jared R.

    2004-01-01

    This article reviews the development of community marriage initiatives and their relationship with family professionals, with particular emphasis on sociohistorical context. We describe five leading community marriage initiatives, discuss the state of the evaluation research, and propose new directions for this promising area of work.

  2. Software Architecture Technology Initiative

    DTIC Science & Technology

    2007-05-01

    2007 Carnegie Mellon University Software Architecture Technology Initiative Mark Klein Third Annual SATURN Workshop May 2007 Report Documentation...3. DATES COVERED 00-00-2007 to 00-00-2007 4. TITLE AND SUBTITLE Software Architecture Technology Initiative 5a. CONTRACT NUMBER 5b. GRANT...STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES presented at the SEI Software Architecture Technology User

  3. The Fostering Hope Initiative

    ERIC Educational Resources Information Center

    Rider, Steven; Winters, Katie; Dean, Joyce; Seymour, Jim

    2014-01-01

    The Fostering Hope Initiative is a neighborhood-based Collective Impact initiative that promotes optimum child and youth development by supporting vulnerable families, encouraging connections between neighbors, strengthening systems to ensure collective impact, and advocating for family-friendly public policy. This article describes the…

  4. Winning with Initiative

    ERIC Educational Resources Information Center

    Morgan, Matthew J.

    2004-01-01

    A common complaint among high school coaches is the lack of initiative shown by some of their players. Coaches expect a certain level of decision-making and independence, and more so from team captains and senior players. Developing leadership skills is a major benefit to athletes who participate at a competitive level, and taking initiative can…

  5. Did CDM particles of mass 2.47 x 10(-3) eV interact with precursor biopolymers and nucleic acids to initiate and boost lifeforms on Earth?

    PubMed

    Rosen, Gerald

    2011-06-01

    Recent observations and theoretical studies have shown that non-baryonic Cold Dark Matter (CDM), which constitutes about 84% of all matter in the Universe, may feature a complex-scalar-field that carries particles of mass ≅ 2.47 x 10(-3)eV with the associated Compton range m(-1) ≅8.02 x 10(-3) cm, a distance on the scale of extended bionucleic acids and living cells. Such a complex-scalar-field can enter a weak-isospin Lorentz-invariant interaction that generates the flow of right-handed electrons and induces a chirality-imbued quantum chemistry on the m (-1) scale. A phenomenological Volterra-type equation is proposed for the CDM-impacted time development of N, the number of base pairs in the most advanced organism at Earth-age t. The solution to this equation suggests that the boosts in N at t ≅ 1.1 Gyr (advent of the first living prokaryotic cells), at t ≅ 2.9 Gyr (advent of eukaryotic single-celled organisms) and finally at t ≅ 4.0 Gyr (the Cambrian explosion) may be associated with three multi-Myr-duration cosmic showers of the complex-scalar-field CDM particles. If so, the signature of the particles may be detectible in Cambrian rocks.

  6. Did CDM Particles of Mass 2.47 × 10-3 eV Interact with Precursor Biopolymers and Nucleic Acids to Initiate and Boost Lifeforms on Earth?

    NASA Astrophysics Data System (ADS)

    Rosen, Gerald

    2011-06-01

    Recent observations and theoretical studies have shown that non-baryonic Cold Dark Matter (CDM), which constitutes about 84% of all matter in the Universe, may feature a complex-scalar-field that carries particles of mass m ≅ 2.47 × {10^{{ - 3}}}eV with the associated Compton range {m^{{ - 1}}} ≅ 8.02 × {10^{{ - 3}}}cm, a distance on the scale of extended bionucleic acids and living cells. Such a complex-scalar-field can enter a weak-isospin Lorentz-invariant interaction that generates the flow of right-handed electrons and induces a chirality-imbued quantum chemistry on the m -1 scale. A phenomenological Volterra-type equation is proposed for the CDM-impacted time development of N, the number of base pairs in the most advanced organism at Earth-age t. The solution to this equation suggests that the boosts in N at t ≅ 1.1 Gyr (advent of the first living prokaryotic cells), at t ≅ 2.9 Gyr (advent of eukaryotic single-celled organisms) and finally at t ≅ 4.0 Gyr (the Cambrian explosion) may be associated with three multi-Myr-duration cosmic showers of the complex-scalar-field CDM particles. If so, the signature of the particles may be detectible in Cambrian rocks.

  7. Folic Acid

    MedlinePlus

    Folic acid is used to treat or prevent folic acid deficiency. It is a B-complex vitamin needed by ... Folic acid comes in tablets. It usually is taken once a day. Follow the directions on your prescription label ...

  8. Aspartic acid

    MedlinePlus

    ... also called asparaginic acid. Aspartic acid helps every cell in the body work. It plays a role in: Hormone production and release Normal nervous system function Plant sources of aspartic acid include: Legumes such as ...

  9. Glioma residual or recurrence versus radiation necrosis: accuracy of pentavalent technetium-99m-dimercaptosuccinic acid [Tc-99m (V) DMSA] brain SPECT compared to proton magnetic resonance spectroscopy (1H-MRS): initial results.

    PubMed

    Amin, Amr; Moustafa, Hosna; Ahmed, Ebaa; El-Toukhy, Mohamed

    2012-02-01

    We compared pentavalent technetium-99m dimercaptosuccinic acid (Tc-99m (V) DMSA) brain single photon emission computed tomography (SPECT) and proton magnetic resonance spectroscopy ((1)H-MRS) for the detection of residual or recurrent gliomas after surgery and radiotherapy. A total of 24 glioma patients, previously operated upon and treated with radiotherapy, were studied. SPECT was acquired 2-3 h post-administration of 555-740 MBq of Tc-99m (V) DMSA. Lesion to normal (L/N) delayed uptake ratio was calculated as: mean counts of tumor ROI (L)/mean counts of normal mirror symmetric ROI (N). (1)H-MRS was performed using a 1.5-T scanner equipped with a spectroscopy package. SPECT and (1)H-MRS results were compared with pathology or follow-up neuroimaging studies. SPECT and (1)H-MRS showed concordant residue or recurrence in 9/24 (37.5%) patients. Both were true negative in 6/24 (25%) patients. SPECT and (1)H-MRS disagreed in 9 recurrences [7/9 (77.8%) and 2/9 (22.2%) were true positive by SPECT and (1)H-MRS, respectively]. Sensitivity of SPECT and (1)H-MRS in detecting recurrence was 88.8 and 61.1% with accuracies of 91.6 and 70.8%, respectively. A positive association between the delayed L/N ratio and tumor grade was found; the higher the grade, the higher is the L/N ratio (r = 0.62, P = 0.001). Tc-99m (V) DMSA brain SPECT is more accurate compared to (1)H-MRS for the detection of tumor residual tissues or recurrence in glioma patients with previous radiotherapy. It allows early and non-invasive differentiation of residual tumor or recurrence from irradiation necrosis.

  10. The Omega-3 fatty acids (Fish Oils) and Aspirin in Vascular access OUtcomes in REnal Disease (FAVOURED) study: the updated final trial protocol and rationale of post-initiation trial modifications.

    PubMed

    Viecelli, Andrea K; Pascoe, Elaine; Polkinghorne, Kevan R; Hawley, Carmel; Paul-Brent, Peta-Anne; Badve, Sunil V; Cass, Alan; Heritier, Stephane; Kerr, Peter G; Mori, Trevor A; Robertson, Amanda; Seong, Hooi L; Irish, Ashley B

    2015-06-27

    The FAVOURED study is an international multicentre, double-blind, placebo-controlled trial which commenced recruitment in 2008 and examines whether omega-3 polyunsaturated fatty acids (omega-3 PUFAs) either alone or in combination with aspirin will effectively reduce primary access failure of de novo arteriovenous fistulae (AVF) in patients with stage 4 and 5 chronic kidney disease. Publication of new evidence derived from additional studies of clopidogrel and a high screen failure rate due to prevalent aspirin usage prompted an updated trial design. The original trial protocol published in 2009 has undergone two major amendments, which were implemented in 2011. Firstly, the primary outcome 'early thrombosis' at 3 months following AVF creation was broadened to a more clinically relevant outcome of 'AVF access failure'; a composite of thrombosis, AVF abandonment and cannulation failure at 12 months. Secondly, participants unable to cease using aspirin were allowed to be enrolled and randomised to omega-3 PUFAs or placebo. The revised primary aim of the FAVOURED study is to test the hypothesis that omega-3 PUFAs will reduce rates of AVF access failure within 12 months following AVF surgery. The secondary aims are to examine the effect of omega-3 PUFAs and aspirin on the individual components of the primary end-point, to examine the safety of study interventions and assess central venous catheter requirement as a result of access failure. This multicentre international clinical trial was amended to address the clinically relevant question of whether the usability of de novo AVF at 12 months can be improved by the early use of omega-3 PUFAs and to a lesser extent aspirin. This study protocol amendment was made in response to a large trial demonstrating that clopidogrel is effective in safely preventing primary AVF thrombosis, but ineffective at increasing functional patency. Secondly, including patients taking aspirin will enroll a more representative cohort of

  11. Autonomous aircraft initiative study

    NASA Technical Reports Server (NTRS)

    Hewett, Marle D.

    1991-01-01

    The results of a consulting effort to aid NASA Ames-Dryden in defining a new initiative in aircraft automation are described. The initiative described is a multi-year, multi-center technology development and flight demonstration program. The initiative features the further development of technologies in aircraft automation already being pursued at multiple NASA centers and Department of Defense (DoD) research and Development (R and D) facilities. The proposed initiative involves the development of technologies in intelligent systems, guidance, control, software development, airborne computing, navigation, communications, sensors, unmanned vehicles, and air traffic control. It involves the integration and implementation of these technologies to the extent necessary to conduct selected and incremental flight demonstrations.

  12. RAS Initiative - Events

    Cancer.gov

    The NCI RAS Initiative has organized multiple events with outside experts to discuss how the latest scientific and technological breakthroughs can be applied to discover vulnerabilities in RAS-driven cancers.

  13. About the RAS Initiative

    Cancer.gov

    The RAS Initiative, a "hub and spoke" model, connects researchers to better understand and target the more than 30% of cancers driven by mutations in RAS genes. Includes oversight and contact information.

  14. RAS Initiative - Community Outreach

    Cancer.gov

    Through community and technical collaborations, workshops and symposia, and the distribution of reference reagents, the RAS Initiative seeks to increase the sharing of knowledge and resources essential to defeating cancers caused by mutant RAS genes.

  15. Project Matching Initiative

    EPA Pesticide Factsheets

    The Green Power Partnership's Project Matching initiative works to connect green power users with new, not-yet-built renewable energy projects that may align with their energy, environmental, and financial objectives.

  16. Advanced Concepts Research Initiative

    EPA Science Inventory

    This initiative is investigating various approaches to controlling and treating wet-weather flow (WWF) discharges in the urban watershed. WWF, including combined sewer overflow (CSO), sanitary sewer overflow (SSO) and stormwater discharges are leading causes of receiving water q...

  17. Advanced Concepts Research Initiative

    EPA Science Inventory

    This initiative is investigating various approaches to controlling and treating wet-weather flow (WWF) discharges in the urban watershed. WWF, including combined sewer overflow (CSO), sanitary sewer overflow (SSO) and stormwater discharges are leading causes of receiving water q...

  18. The RAS Initiative

    Cancer.gov

    NCI established the RAS Initiative to explore innovative approaches for attacking the proteins encoded by mutant forms of RAS genes and to ultimately create effective, new therapies for RAS-related cancers.

  19. Collaborative Procurement Initiative

    EPA Pesticide Factsheets

    GPP's Clean Energy Collaborative Procurement Initiative provides a platform for deploying clean energy technologies across multiple government and educational organizations for maximum impact on installed solar system capacity and local economic activity.

  20. Midwest Clean Diesel Initiative

    EPA Pesticide Factsheets

    The Midwest Clean Diesel Initiative (MCDI) is a collaboration of federal, state and local agencies, along with communities, non-profit organizations and private companies working together by reducing exposure to emissions from diesel engines

  1. PESP Landscaping Initiative

    EPA Pesticide Factsheets

    Landscaping practices can positively or negatively affect local environments and human health. The Landscaping Initiative seeks to enhance benefits of landscaping while reducing need for pesticides, fertilizers, etc., by working with partners.

  2. Piezoelectrically Initiated Pyrotechnic Igniter

    NASA Technical Reports Server (NTRS)

    Quince, Asia; Dutton, Maureen; Hicks, Robert; Burnham, Karen

    2013-01-01

    This innovation consists of a pyrotechnic initiator and piezoelectric initiation system. The device will be capable of being initiated mechanically; resisting initiation by EMF, RF, and EMI (electromagnetic field, radio frequency, and electromagnetic interference, respectively); and initiating in water environments and space environments. Current devices of this nature are initiated by the mechanical action of a firing pin against a primer. Primers historically are prone to failure. These failures are commonly known as misfires or hang-fires. In many cases, the primer shows the dent where the firing pin struck the primer, but the primer failed to fire. In devices such as "T" handles, which are commonly used to initiate the blowout of canopies, loss of function of the device may result in loss of crew. In devices such as flares or smoke generators, failure can result in failure to spot a downed pilot. The piezoelectrically initiated ignition system consists of a pyrotechnic device that plugs into a mechanical system (activator), which on activation, generates a high-voltage spark. The activator, when released, will strike a stack of electrically linked piezo crystals, generating a high-voltage, low-amperage current that is then conducted to the pyro-initiator. Within the initiator, an electrode releases a spark that passes through a pyrotechnic first-fire mixture, causing it to combust. The combustion of the first-fire initiates a primary pyrotechnic or explosive powder. If used in a "T" handle, the primary would ramp the speed of burn up to the speed of sound, generating a shock wave that would cause a high explosive to go "high order." In a flare or smoke generator, the secondary would produce the heat necessary to ignite the pyrotechnic mixture. The piezo activator subsystem is redundant in that a second stack of crystals would be struck at the same time with the same activation force, doubling the probability of a first strike spark generation. If the first

  3. Software Architecture Technology Initiative

    DTIC Science & Technology

    2008-04-01

    2008 Carnegie Mellon University 2008 PLS March 2008 © 2008 Carnegie Mellon University Software Architecture Technology Initiative SATURN 2008...SUBTITLE Software Architecture Technology Initiative 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...SUPPLEMENTARY NOTES presented at the SEI Software Architecture Technology User Network (SATURN) Workshop, 30 Apr ? 1 May 2008, Pittsburgh, PA. 14

  4. National Plant Genome Initiative

    DTIC Science & Technology

    2005-01-01

    JAN 2005 2. REPORT TYPE 3. DATES COVERED 00-00-2005 to 00-00-2005 4. TITLE AND SUBTITLE National Plant Genome Initiative. Progress Report 5a...refl ected in future Administration budgets. Cover Photo: National Plant Genome Initiative Progress Report January 2005 National Science and...Technology Council Committee on Science Interagency Working Group on Plant Genomes [Blank Page] Interagency Working Group on Plant Genomes Committee on

  5. Acid Rain

    USGS Publications Warehouse

    Bricker, Owen P.; Rice, Karen C.

    1995-01-01

    Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidic substances - rain, snow, fog, acidic dry particulates, aerosols, and acid-forming gases. Water in the atmosphere reacts with certain atmospheric gases to become acidic. For example, water reacts with carbon dioxide in the atmosphere to produce a solution with a pH of about 5.6. Gases that produce acids in the presence of water in the atmosphere include carbon dioxide (which converts to carbonic acid), oxides of sulfur and nitrogen (which convert to sulfuric and nitric acids}, and hydrogen chloride (which converts to hydrochloric acid). These acid-producing gases are released to the atmosphere through natural processes, such as volcanic emissions, lightning, forest fires, and decay of organic matter. Accordingly, precipitation is slightly acidic, with a pH of 5.0 to 5.7 even in undeveloped areas. In industrialized areas, most of the acid-producing gases are released to the atmosphere from burning fossil fuels. Major emitters of acid-producing gases include power plants, industrial operations, and motor vehicles. Acid-producing gases can be transported through the atmosphere for hundreds of miles before being converted to acids and deposited as acid rain. Because acids tend to build up in the atmosphere between storms, the most acidic rain falls at the beginning of a storm, and as the rain continues, the acids "wash out" of the atmosphere.

  6. 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)

  7. 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)

  8. Optimal flight initiation distance.

    PubMed

    Cooper, William E; Frederick, William G

    2007-01-07

    Decisions regarding flight initiation distance have received scant theoretical attention. A graphical model by Ydenberg and Dill (1986. The economics of fleeing from predators. Adv. Stud. Behav. 16, 229-249) that has guided research for the past 20 years specifies when escape begins. In the model, a prey detects a predator, monitors its approach until costs of escape and of remaining are equal, and then flees. The distance between predator and prey when escape is initiated (approach distance = flight initiation distance) occurs where decreasing cost of remaining and increasing cost of fleeing intersect. We argue that prey fleeing as predicted cannot maximize fitness because the best prey can do is break even during an encounter. We develop two optimality models, one applying when all expected future contribution to fitness (residual reproductive value) is lost if the prey dies, the other when any fitness gained (increase in expected RRV) during the encounter is retained after death. Both models predict optimal flight initiation distance from initial expected fitness, benefits obtainable during encounters, costs of escaping, and probability of being killed. Predictions match extensively verified predictions of Ydenberg and Dill's (1986) model. Our main conclusion is that optimality models are preferable to break-even models because they permit fitness maximization, offer many new testable predictions, and allow assessment of prey decisions in many naturally occurring situations through modification of benefit, escape cost, and risk functions.

  9. Initiator system in holographic photopolymer materials

    NASA Astrophysics Data System (ADS)

    Ortuño, M.; Fernández, E.; Fuentes, R.; Gallego, S.; Márquez, A.

    2010-05-01

    The photopolymers with a hydrophilic matrix as poly(vinyl alcohol), PVA, are versatile holographic recording materials in hologram recording experiments. They use water as solvent and they can be made in layers with several thickness. One of the photopolymers more used is composed of acrylamide as polymerizable monomer, PVA and water as binder. The pair: triethanolamine, TEA, and the dye yellowish eosin, YE, is widely used as initiator system due to its high sensitivity and efficiency. TEA is the radical initiator more used with dyes derived from fluorescein as YE because they can generate a radical by redox reaction under dye excitation by light. The dye is bleached in this process because is decomposed in the photoinitiation reaction. The ethylenediaminetetraacetic acid EDTA has a molecular structure very similar to TEA and therefore could replace it in this kind of photopolymers. The 4,4' azo-bis-(4-cyanopentanoic acid), ACPA, is a radical initiator that is soluble in water and usually used in polymerizations in solution with thermal initiation. In this work, we use EDTA and ACPA in order to check their properties as radical initiator in the photochemical reaction that takes place inside the photopolymer while a hologram is being recorded. We will compare the results obtained with those derived from TEA and will evaluate the possibilities for these substances.

  10. STI Program Multimedia Initiative

    NASA Technical Reports Server (NTRS)

    Cotter, Gladys A.; Kaye, Karen

    1993-01-01

    This paper relates the experience of the NASA Scientific and Technical Information Program in introducing multimedia within the STI Program framework. A discussion of multimedia technology is included to provide context for the STI Program effort. The STI Program's Multimedia Initiative is discussed in detail. Parallels and differences between multimedia and traditional information systems project development are highlighted. Challenges faced by the program in initiating its multimedia project are summarized along with lessons learned. The paper concludes with a synopsis of the benefits the program hopes to provide its users through the introduction of multimedia illustrated by examples of successful multimedia projects.

  11. Civil space technology initiative

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Civil Space Technology Initiative (CSTI) is a major, focused, space technology program of the Office of Aeronautics, Exploration and Technology (OAET) of NASA. The program was initiated to advance technology beyond basic research in order to expand and enhance system and vehicle capabilities for near-term missions. CSTI takes critical technologies to the point at which a user can confidently incorporate the new or expanded capabilities into relatively near-term, high-priority NASA missions. In particular, the CSTI program emphasizes technologies necessary for reliable and efficient access to and operation in Earth orbit as well as for support of scientific missions from Earth orbit.

  12. Shock initiation of nitromethane

    SciTech Connect

    Yoo, C.S.; Holmes, N.C.

    1993-12-31

    The shock initiation processes of nitromethane have been examined by using a fast time-resolved emission spectroscopy at a two-stage gas gun. a broad, but strong emission has been observed in a spectral range between 350 and 700 nm from shocked nitromethane above 9 GPa. The temporal profile suggests that shocked nitromethane detonates through three characteristic periods, namely an induction period, a hock initiation period, and a thermal explosion period. This paper discusses temporal and chemical characteristics of these periods and present the temperature of the shock-detonating nitromethane at pressures between 9 and 15 GPa.

  13. Statistical initial orbit determination

    SciTech Connect

    Taff, L.G.; Belkin, B.; Schweiter, G.A.; Sommar, K. D.H. Wagner Associates, Inc., Paoli, PA )

    1992-02-01

    For the ballistic missile initial orbit determination problem in particular, the concept of 'launch folders' is extended. This allows to decouple the observational data from the initial orbit determination problem per se. The observational data is only used to select among the possible orbital element sets in the group of folders. Monte Carlo simulations using up to 7200 orbital element sets are described. The results are compared to the true orbital element set and the one a good radar would have been able to produce if collocated with the optical sensor. The simplest version of the new method routinely outperforms the radar initial orbital element set by a factor of two in future miss distance. In addition, not only can a differentially corrected orbital element set be produced via this approach - after only two measurements of direction - but also an updated, meaningful, six-dimensional covariance array for it can be calculated. This technique represents a significant advance in initial orbit determination for this problem, and the concept can easily be extended to minor planets and artificial satellites. 9 refs.

  14. The SEED Initiative

    ERIC Educational Resources Information Center

    Teich, Carolyn R.

    2011-01-01

    Committed to fulfilling the promise of the green economy, the American Association of Community Colleges (AACC) launched the Sustainability Education and Economic Development (SEED) initiative (www.theseedcenter.org) in October 2010. The project advances sustainability and clean energy workforce development practices at community colleges by…

  15. Department-Initiated Change

    ERIC Educational Resources Information Center

    Watson, Anne; De Geest, Els

    2014-01-01

    This paper reports the activity of three secondary school mathematics departments in England in self-initiated states of change that led to overall improvements in students' achievements when compared to previous cohorts. This took place without intervention and without their participation in external projects. They provide examples of departments…

  16. Monolithic exploding foil initiator

    DOEpatents

    Welle, Eric J; Vianco, Paul T; Headley, Paul S; Jarrell, Jason A; Garrity, J. Emmett; Shelton, Keegan P; Marley, Stephen K

    2012-10-23

    A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.

  17. Strategic Defense Initiative program

    SciTech Connect

    Conachan, F.C.

    1991-05-01

    This paper discusses the Strategic Defense Initiative (SDI) program. It summarizes the major programmatic and technological lessons learned from the SDI program over the past 7 years. It provides information on: past uses of SDI funds, persistent optimism in planning and starting projects, evolution of SDI architecture, and accuracy of cost estimates.

  18. Best Practices & Outstanding Initiatives

    ERIC Educational Resources Information Center

    Training, 2011

    2011-01-01

    In this article, "Training" editors recognize innovative and successful learning and development programs and practices. They share best practices from Automatic Data Processing, Inc., Farmers Insurance Group, FedEx Express, InterContinental Hotels Group, and Oakwood Temporary Housing. They also present the outstanding initiatives of EMD Serono,…

  19. Sourcebook of Restructuring Initiatives.

    ERIC Educational Resources Information Center

    Stefkovich, Jacqueline A., Ed.

    This three-part sourcebook identifies school restructuring initiatives with a national scope and presents comprehensive information about them. Part 1 identifies and describes national restructuring programs (e.g., Coalition of Essential Schools, Learning Tomorrow, Success for All). Each program description provides an overview of the program as…

  20. Transformative Change Initiative

    ERIC Educational Resources Information Center

    Bragg, D. D.; Kirby, C.; Witt, M. A.; Richie, D.; Mix, S.; Feldbaum, M.; Liu, S.; Mason, M.

    2014-01-01

    The Transformative Change Initiative (TCI) is dedicated to assisting community colleges to scale up innovation in the form of guided pathways, programs of study, and evidence-based strategies to improve student outcomes and program, organization, and system performance. The impetus for TCI is the Trade Adjustment Assistance Community College and…

  1. Clean Energy Manufacturing Initiative

    SciTech Connect

    2013-04-01

    The initiative will strategically focus and rally EERE’s clean energy technology offices and Advanced Manufacturing Office around the urgent competitive opportunity for the United States to be the leader in the clean energy manufacturing industries and jobs of today and tomorrow.

  2. Envisioning Effective Laptop Initiatives

    ERIC Educational Resources Information Center

    Clausen, Jon M.; Britten, Jody; Ring, Gail

    2008-01-01

    A recent survey of 74 building-level school administrators in Indiana challenged many of the assumptions regarding 1:1 laptop initiatives and how 1:1 access would affect teaching and learning. It also revealed disturbing realities regarding instructional practices of teachers, as well as efforts to improve school technology integration. The intent…

  3. Kinesthetic Initial Training.

    ERIC Educational Resources Information Center

    Ostrom, Gladys

    1978-01-01

    The author's plans for Kinesthetic Initial Training (KIT), a system of interrelated subjects designed to teach handicapped and gifted students basic reading, writing, arithmetic, and grammar skills through the use of concrete materials, are described. KIT components are reviewed, and implications are considered for areas of psychomotor,…

  4. Best Practices & Outstanding Initiatives

    ERIC Educational Resources Information Center

    Training, 2011

    2011-01-01

    In this article, "Training" editors recognize innovative and successful learning and development programs and practices. They share best practices from Automatic Data Processing, Inc., Farmers Insurance Group, FedEx Express, InterContinental Hotels Group, and Oakwood Temporary Housing. They also present the outstanding initiatives of EMD Serono,…

  5. Department-Initiated Change

    ERIC Educational Resources Information Center

    Watson, Anne; De Geest, Els

    2014-01-01

    This paper reports the activity of three secondary school mathematics departments in England in self-initiated states of change that led to overall improvements in students' achievements when compared to previous cohorts. This took place without intervention and without their participation in external projects. They provide examples of departments…

  6. Information Technology Initiative (Videorecording),

    DTIC Science & Technology

    Physical description: 1 VHS video; col.; sd.; mono.; standard playback sp.; 35:40 mins.; 1/2 in. In this video, Dr. Kurt Fisher, Deputy Director for Information Technology , introduces the Corporate Information Management (CIM) program and explains the following major technical initiatives: reuse/repositories; I-case; data administration; information technology architecture; software process improvement; standards.

  7. Mixed-Initiative Clustering

    ERIC Educational Resources Information Center

    Huang, Yifen

    2010-01-01

    Mixed-initiative clustering is a task where a user and a machine work collaboratively to analyze a large set of documents. We hypothesize that a user and a machine can both learn better clustering models through enriched communication and interactive learning from each other. The first contribution or this thesis is providing a framework of…

  8. Mixed-Initiative Clustering

    ERIC Educational Resources Information Center

    Huang, Yifen

    2010-01-01

    Mixed-initiative clustering is a task where a user and a machine work collaboratively to analyze a large set of documents. We hypothesize that a user and a machine can both learn better clustering models through enriched communication and interactive learning from each other. The first contribution or this thesis is providing a framework of…

  9. Ontario's Student Voice Initiative

    ERIC Educational Resources Information Center

    Courtney, Jean

    2014-01-01

    This article describes in some detail aspects of the Student Voice initiative funded and championed by Ontario's Ministry of Education since 2008. The project enables thousands of students to make their voices heard in meaningful ways and to participate in student-led research. Some students from grades 7 to 12 become members of the Student…

  10. Initial Teaching Orthographies.

    ERIC Educational Resources Information Center

    Dewey, Godfrey

    To achieve its purpose, an initial teaching orthography (i.t.o.) should be as simple in form and substance as possible; it should be phonemic rather than phonetic. The 40 sounds distinguished by Pitmanic shorthand and some provision for schwa can serve as a basic code. The symbols can be derived from either of two major sources--standardizing the…

  11. Focusing educational initiatives

    NASA Technical Reports Server (NTRS)

    Parks, George K.

    1990-01-01

    The United States will soon be facing a critical shortage of aerospace scientists and engineers. To address this problem, Space Grant Colleges can assist in focusing interest in existing educational initiatives and in creating new educational opportunities, particularly for women and underrepresented minorities.

  12. America's Caribbean Basin Initiative.

    ERIC Educational Resources Information Center

    Kasten, Robert W.

    1983-01-01

    Nearly all of the countries that have succeeded in their development over the past 30 years have done so on the strength of market-oriented policies and vigorous participation in the international economy. Aid must be complemented by trade and investment. The Caribbean Basin Initiative puts these principles into practice. (RM)

  13. Next generation initiation techniques

    NASA Technical Reports Server (NTRS)

    Warner, Tom; Derber, John; Zupanski, Milija; Cohn, Steve; Verlinde, Hans

    1993-01-01

    Four-dimensional data assimilation strategies can generally be classified as either current or next generation, depending upon whether they are used operationally or not. Current-generation data-assimilation techniques are those that are presently used routinely in operational-forecasting or research applications. They can be classified into the following categories: intermittent assimilation, Newtonian relaxation, and physical initialization. It should be noted that these techniques are the subject of continued research, and their improvement will parallel the development of next generation techniques described by the other speakers. Next generation assimilation techniques are those that are under development but are not yet used operationally. Most of these procedures are derived from control theory or variational methods and primarily represent continuous assimilation approaches, in which the data and model dynamics are 'fitted' to each other in an optimal way. Another 'next generation' category is the initialization of convective-scale models. Intermittent assimilation systems use an objective analysis to combine all observations within a time window that is centered on the analysis time. Continuous first-generation assimilation systems are usually based on the Newtonian-relaxation or 'nudging' techniques. Physical initialization procedures generally involve the use of standard or nonstandard data to force some physical process in the model during an assimilation period. Under the topic of next-generation assimilation techniques, variational approaches are currently being actively developed. Variational approaches seek to minimize a cost or penalty function which measures a model's fit to observations, background fields and other imposed constraints. Alternatively, the Kalman filter technique, which is also under investigation as a data assimilation procedure for numerical weather prediction, can yield acceptable initial conditions for mesoscale models. The

  14. ROXARSONE AND TRANSFORMATION PRODUCTS IN CHICKEN MANURE: DETERMINATION BY CAPILLARY ELECTROPHORESIS-INDUCTIVELY COUPLES PLASMA MASS SPECTROMERTY

    EPA Science Inventory

    The determination of the animal feed additive roxarsone (3-nitro-4- hydroxyphenylarsonic acid) and six of its possible transfonnation products (arsenite, arsenate, monomethylarsonate, dimethylarsinate, 3-amino-4-hydroxyphenylarsonic acid, and 4-hydroxyphenylarsonic acid) in chi...

  15. ROXARSONE AND TRANSFORMATION PRODUCTS IN CHICKEN MANURE: DETERMINATION BY CAPILLARY ELECTROPHORESIS-INDUCTIVELY COUPLES PLASMA MASS SPECTROMERTY

    EPA Science Inventory

    The determination of the animal feed additive roxarsone (3-nitro-4- hydroxyphenylarsonic acid) and six of its possible transfonnation products (arsenite, arsenate, monomethylarsonate, dimethylarsinate, 3-amino-4-hydroxyphenylarsonic acid, and 4-hydroxyphenylarsonic acid) in chi...

  16. Acid rain

    SciTech Connect

    Stensland, G.J.

    1983-11-01

    A series of definitions for the field of acid rain studies are presented. Protocols for acid rain sampling and monitoring are also presented. A procedure for calculatory precipitation pH is discussed. 11 references, 1 table.

  17. Folic acid

    MedlinePlus

    ... of childhood cancer of the white blood cells. Iron deficiency. Taking folic acid with iron supplements is not ... supplements without folic acid for treating and preventing iron deficiency and anemia caused by too little iron in ...

  18. Aminocaproic Acid

    MedlinePlus

    Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

  19. Obeticholic Acid

    MedlinePlus

    Obeticholic acid is used alone or in combination with ursodiol (Actigall, Urso) to treat primary biliary cholangitis (PBC; a ... were not treated successfully with ursodiol alone. Obeticholic acid is in a class of medications called farnesoid ...

  20. Acid mucopolysaccharides

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003368.htm Acid mucopolysaccharides To use the sharing features on this page, please enable JavaScript. Acid mucopolysaccharides is a test that measures the amount ...

  1. Ethacrynic Acid

    MedlinePlus

    Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

  2. Ascorbic Acid

    MedlinePlus

    Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C in ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops to ...

  3. Aristolochic Acids

    MedlinePlus

    ... Sciences NIH-HHS www.niehs.nih.gov Aristolochic Acids Key Points Report on Carcinogens Status Known to be human carcinogens Aristolochia Clematitis Aristolochic Acids n Known human carcinogens n Found in certain ...

  4. Amino acids

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002222.htm Amino acids To use the sharing features on this page, please enable JavaScript. Amino acids are organic compounds that combine to form proteins . ...

  5. Mefenamic Acid

    MedlinePlus

    Mefenamic acid is used to relieve mild to moderate pain, including menstrual pain (pain that happens before or during a menstrual period). Mefenamic acid is in a class of medications called NSAIDs. ...

  6. Oklahoma Healthy Homes initiative.

    PubMed

    Khan, Fahad

    2011-01-01

    Compelling scientific evidence suggests that a strong association exists between housing-related hazards and the health and safety of their residents. Health, safety, and environmental hazards (such as asthma and allergy triggers), unintentional injury hazards, lead-based paint hazards, and poor indoor air quality are interrelated with substandard housing conditions. This article describes a Healthy Homes initiative to address these hazards in a coordinated fashion in the home, rather than taking a categorical approach, even in the presence of multiple hazards. It also provides an overview of Oklahoma's Healthy Homes initiative and its pilot project, the Tulsa Safe and Healthy Housing Project, which is currently administered in Tulsa in collaboration with Children First, Oklahoma's Nurse-Family Partnership program. This pilot project seeks to open new areas of research that can lead to a greater understanding of environmental health issues related to substandard housing in the United States, which will eventually make homes safer and healthier.

  7. The TRANSPLANTEX initiative.

    PubMed

    Bahram, Seiamak; Carapito, Raphael; Gourraud, Pierre-Antoine; Charron, Dominique

    2016-11-01

    TRANSPLANTEX, a French "investment for the future" initiated consortium of leading transplant units and research laboratories across France and a number of European countries aims to unravel, through mainly high-throughput genomics (and other omics) analyses of donor and recipients, novel (a) non-HLA, histocompatibility antigens, whether inside, or outside the MHC; (b) pre/post transplantation biomarkers. This shall lead to our better understanding of the pathophysiology of (and eventually designing better therapeutics for) the graft-versus-host disease in hematopoietic cell transplants and that of chronic graft rejection after kidney transplant. Industrial developments as well as innovative teaching initiatives are also integral part of this program. The present issue of Human Immunology aims to present a first snapshot of some of the research performed by TRANPLANTEX partners. Copyright © 2016. Published by Elsevier Inc.

  8. Antarctic Geoscience Initiative

    NASA Astrophysics Data System (ADS)

    Dalziel, Ian W. D.; Zimmerman, Herman B.

    Antarctia has recently been described as a continent surrounded by advice. The advice stems from growing realization of the Antarctic's importance in many aspects of globalscale Earth science. This article outlines a U.S. and international initiative to move solid-Earth scientists from an advisory role to one of acquiring new data bearing on the structure and evolution of the ice-covered Antarctic lithosphere.The initiative has marine, airborne, and terrestrial components; plans for all three are underway. Platforms exist for undertaking the work at sea and in the air, but land geophysical techniques need to be adapted to the Antarctic environment. An international workshop to plan modern over-ice geoscience transects will be convened in Washington, D.C., July 19-22 in conjunction with the 28th International Geological Congress (IGC).

  9. Gravity wave initiated convection

    NASA Technical Reports Server (NTRS)

    Hung, R. J.

    1990-01-01

    The vertical velocity of convection initiated by gravity waves was investigated. In one particular case, the convective motion-initiated and supported by the gravity wave-induced activity (excluding contributions made by other mechanisms) reached its maximum value about one hour before the production of the funnel clouds. In another case, both rawinsonde and geosynchronous satellite imagery were used to study the life cycles of severe convective storms. Cloud modelling with input sounding data and rapid-scan imagery from GOES were used to investigate storm cloud formation, development and dissipation in terms of growth and collapse of cloud tops, as well as, the life cycles of the penetration of overshooting turrets above the tropopause. The results based on these two approaches are presented and discussed.

  10. COTS Initiative Panel Discussion

    NASA Image and Video Library

    2013-11-13

    Phil McAlister, Director of Commercial Spaceflight Development at NASA, delivers remarks panel discussion on the Commercial Orbital Transportation Services (COTS) initiative at NASA Headquarters in Washington on Wednesday, November 13, 2013. Through COTS, NASA's partners Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp., developed new U.S. rockets and spacecraft, launched from U.S. soil, capable of transporting cargo to low-Earth orbit and the International Space Station. Photo Credit: (NASA/Jay Westcott)

  11. Overview of Explosive Initiators

    DTIC Science & Technology

    2015-11-01

    Primary explosive Initiator Detonator Primer Blasting cap Lead azide Lead styphnate 16. SECURITY CLASSIFICATION OF...Conclusions 13 References 15 Distribution List 17 FIGURES 1 Decomposition reaction of lead azide in the presence of carbon dioxide and water (ref...the world, currently the most popular are lead azide (Pb(N3)2) and lead styphnate (both normal and basic forms) and tetrazene. With its high explosive

  12. The NLM Indexing Initiative.

    PubMed Central

    Aronson, A. R.; Bodenreider, O.; Chang, H. F.; Humphrey, S. M.; Mork, J. G.; Nelson, S. J.; Rindflesch, T. C.; Wilbur, W. J.

    2000-01-01

    The objective of NLM's Indexing Initiative (IND) is to investigate methods whereby automated indexing methods partially or completely substitute for current indexing practices. The project will be considered a success if methods can be designed and implemented that result in retrieval performance that is equal to or better than the retrieval performance of systems based principally on humanly assigned index terms. We describe the current state of the project and discuss our plans for the future. PMID:11079836

  13. The NLM Indexing Initiative.

    PubMed

    Aronson, A R; Bodenreider, O; Chang, H F; Humphrey, S M; Mork, J G; Nelson, S J; Rindflesch, T C; Wilbur, W J

    2000-01-01

    The objective of NLM's Indexing Initiative (IND) is to investigate methods whereby automated indexing methods partially or completely substitute for current indexing practices. The project will be considered a success if methods can be designed and implemented that result in retrieval performance that is equal to or better than the retrieval performance of systems based principally on humanly assigned index terms. We describe the current state of the project and discuss our plans for the future.

  14. Genetics of Fiber Initiation

    USDA-ARS?s Scientific Manuscript database

    To study the cellular mechanisms involved in fiber initiation, three fiberless lines were crossed with wildtype and fuzzless seed cotton and the F1, F2 and BC1 progeny ratios are presently being evaluated. The three fiberless lines included: MD17 (N1N1n2n2), SL1-7-1 (N1N1fl1fl1n3n3) and XZ142w. XZ...

  15. COTS Initiative Panel Discussion

    NASA Image and Video Library

    2013-11-13

    Gwynne Shotwell, President of SpaceX, delivers remarks panel discussion on the Commercial Orbital Transportation Services (COTS) initiative at NASA Headquarters in Washington on Wednesday, November 13, 2013. Through COTS, NASA's partners Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp., developed new U.S. rockets and spacecraft, launched from U.S. soil, capable of transporting cargo to low-Earth orbit and the International Space Station. Photo Credit: (NASA/Jay Westcott)

  16. COTS Initiative Panel Discussion

    NASA Image and Video Library

    2013-11-13

    NASA Administrator Charles Bolden delivers remarks before a panel discussion on the Commercial Orbital Transportation Services (COTS) initiative at NASA Headquarters in Washington on Wednesday, November 13, 2013. Through COTS, NASA's partners Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp., developed new U.S. rockets and spacecraft, launched from U.S. soil, capable of transporting cargo to low-Earth orbit and the International Space Station. Photo Credit: (NASA/Jay Westcott)

  17. COTS Initiative Panel Discussion

    NASA Image and Video Library

    2013-11-13

    Frank Slazer, Vice President of Space Systems, Aerospace Industries Association, delivers remarks panel discussion on the Commercial Orbital Transportation Services (COTS) initiative at NASA Headquarters in Washington on Wednesday, November 13, 2013. Through COTS, NASA's partners Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp., developed new U.S. rockets and spacecraft, launched from U.S. soil, capable of transporting cargo to low-Earth orbit and the International Space Station. Photo Credit: (NASA/Jay Westcott)

  18. Iterative initial condition reconstruction

    NASA Astrophysics Data System (ADS)

    Schmittfull, Marcel; Baldauf, Tobias; Zaldarriaga, Matias

    2017-07-01

    Motivated by recent developments in perturbative calculations of the nonlinear evolution of large-scale structure, we present an iterative algorithm to reconstruct the initial conditions in a given volume starting from the dark matter distribution in real space. In our algorithm, objects are first moved back iteratively along estimated potential gradients, with a progressively reduced smoothing scale, until a nearly uniform catalog is obtained. The linear initial density is then estimated as the divergence of the cumulative displacement, with an optional second-order correction. This algorithm should undo nonlinear effects up to one-loop order, including the higher-order infrared resummation piece. We test the method using dark matter simulations in real space. At redshift z =0 , we find that after eight iterations the reconstructed density is more than 95% correlated with the initial density at k ≤0.35 h Mpc-1 . The reconstruction also reduces the power in the difference between reconstructed and initial fields by more than 2 orders of magnitude at k ≤0.2 h Mpc-1 , and it extends the range of scales where the full broadband shape of the power spectrum matches linear theory by a factor of 2-3. As a specific application, we consider measurements of the baryonic acoustic oscillation (BAO) scale that can be improved by reducing the degradation effects of large-scale flows. In our idealized dark matter simulations, the method improves the BAO signal-to-noise ratio by a factor of 2.7 at z =0 and by a factor of 2.5 at z =0.6 , improving standard BAO reconstruction by 70% at z =0 and 30% at z =0.6 , and matching the optimal BAO signal and signal-to-noise ratio of the linear density in the same volume. For BAO, the iterative nature of the reconstruction is the most important aspect.

  19. Laser Initiated Actuator study

    SciTech Connect

    Watson, B.

    1991-06-27

    The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.

  20. OSM's reforestation initiative

    SciTech Connect

    Boyce, J.S.

    1999-07-01

    Implementation of the Surface Mining Control and Reclamation Act (SMCRA) has discouraged reforestation in some situations where reforestation would be desirable. OSM is engaged in an initiative to increase the amount of mined land reclaimed to forest where appropriate. The authors are seeking to determine those elements of the Federal/State regulator programs that discourage reforestation and find ways to offset these impacts. Potential factors militating against reforestation are identified and possible solutions are discussed.

  1. COTS Initiative Panel Discussion

    NASA Image and Video Library

    2013-11-13

    Alan Lindenmoyer, Manager of Commercial Crew and Cargo Program at NASA, delivers remarks panel discussion on the Commercial Orbital Transportation Services (COTS) initiative at NASA Headquarters in Washington on Wednesday, November 13, 2013. Through COTS, NASA's partners Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp., developed new U.S. rockets and spacecraft, launched from U.S. soil, capable of transporting cargo to low-Earth orbit and the International Space Station. Photo Credit: (NASA/Jay Westcott)

  2. The space exploration initiative

    NASA Technical Reports Server (NTRS)

    Priest, Pete

    1991-01-01

    A number of view graph charts are presented which outline the presentation. Outlined are reasons for going to Mars, why it is necessary to go to the Moon first, and the presidential decision on the space exploration initiative. Other representative charts are entitled: Lunar transportation system requirement drivers; Mars transportation system requirement drivers; National space policy goals; Exploration hardware needed; Mars mission profile; Science on the Moon and Mars; and Two independent reviews.

  3. Valproic Acid

    MedlinePlus

    Valproic acid is used alone or with other medications to treat certain types of seizures. Valproic acid is also used to treat mania (episodes of ... to relieve headaches that have already begun. Valproic acid is in a class of medications called anticonvulsants. ...

  4. Initiation Train Experiments

    NASA Astrophysics Data System (ADS)

    Francois, Elizabeth; Johnson, Carl; Liechty, Gary; Whitley, Von

    2015-06-01

    In an effort to evaluate and qualify a new detonator diagnostic, booster selection and main charge configuration, a variety of small-scale tests have been conducted. This paper will describe the needs, testing approach and model validation. Because of the limited size available some novel approaches were made to understand the observed phenomenon. Function time and time of arrival at various locations in the initiation train are desirable data points. Knowing when each segment initiates the next segment and the time to run up to detonation is critical. Results of our experiments were modeled for timing accuracy, wave shape and pressure. Agreement between the experiments and models will be discussed. The testing that will be discussed is time of arrival wires, PDV, and fiber optic arrays. The time of arrival wire measures the detonator cup breakout time. When correlated to bridge burst, an absolute time is collected. This data point also gives time zero for the booster initiation. Many models actually start at the booster, rather than the detonator, so the inclusion of this data point will improve modeling efforts.

  5. Initial conditions for inflation

    NASA Astrophysics Data System (ADS)

    Dimopoulos, Konstantinos; Artymowski, Michał

    2017-09-01

    Within the α-attractors framework we investigate scalar potentials with the same pole as the one featured in the kinetic term. We show that, in field space, this leads to directions without a plateau. Using this, we present a proposal, which manages to overcome the initial conditions problem of inflation with a plateau. An earlier period of proto-inflation, beginning at Planck scale, accounts for the Universe expansion and arranges the required initial conditions for inflation on the plateau to commence. We show that, if proto-inflation is power-law, it does not suffer from a sub-Planckian eternal inflationary stage, which would otherwise be a problem. A simple model realisation is constructed in the context of α-attractors, which can both generate the inflationary plateau and the exponential slopes around it, necessary for the two inflation stages. Our mechanism allows to assume chaotic initial conditions at the Planck scale for proto-inflation, it is generic and it is shown to work without fine-tuning.

  6. MSI develops refugee initiative.

    PubMed

    1996-01-01

    This brief article highlights the new initiative by Marie Stopes International (MSI), which is part of a Reproductive Health for Refugees Consortium of four organizations formed in 1995. The new initiative will promote awareness about the need for reproductive health among refugees. Over 80% of refugees are women and children who fled a variety of disasters only to be at high risk from sexual violence, sexually transmitted infections, and the effects of unintended and unsafe pregnancies. The consortium members will work to increase donors' understanding of the health conditions of women and to significantly increase donor support for reproductive health initiatives. In addition to the role of advocacy, MSI will be introducing refugee services into its global network of reproductive health services. MSI gained experience in delivering reproductive health services in refugee situations in the former Yugoslavia and among Mozambican refugees in Malawi. MSI is investigating sources of information from several countries about refugees' needs. The consortium is also collecting information on the most effective ways of delivering reproductive health services in refugee situations. The aim is to institutionalize reproductive health services into all humanitarian responses. MSI has developed refugee programs over the past 3 years in the former Yugoslavia, Malawi, Sri Lanka, and Sierra Leone. MSI expects to establish projects in 1996 for refugees in Zaire, Guinea, and Mozambique. The numbers of displaced persons or refugees is continuing to increase worldwide, and there is a continued need to provide for these vulnerable communities.

  7. Initiation of dialysis.

    PubMed

    Hakim, R M; Lazarus, J M

    1995-11-01

    The decision to initiate dialysis in a patient with progressive renal disease often depends on the physician's assessment of the patient's subjective symptoms of uremia. There is an increasing need to identify objective criteria for such a decision. Recent evidence suggests that malnutrition at the initiation of dialysis is a strong predictor of subsequent increased relative risk of death on dialysis. In this context, the role of prescribed protein restriction as well as the influence of the progression of renal disease on spontaneous dietary protein intake is examined. It is proposed that the indices of malnutrition such as progressive weight loss, serum albumin levels below 4.0 g/dL, serum transferrin levels below 200 mg/dL, and spontaneous dietary protein intake (using 24-hr urinary nitrogen measurement) below 0.8 to 0.7 g/kg per day be considered as objective criteria for the initiation of dialysis. Studies that have examined the role of "early" versus "late" dialysis have consistently shown a better outcome in the patients starting dialysis early. Other studies also suggest that early referral to nephrologists results in improved morbidity and mortality as well as hospitalization costs. An adequate vascular access, as well as social and psychological preparation of the patient, is an important early step in the process.

  8. The Cincinnati Payer Initiative.

    PubMed

    Pruett, S H; Werner, T; Hein, J

    1996-01-01

    In 1991, four companies (Procter & Gamble, General Electric, Cincinnati Bell, and Kroger) located in Cincinnati, OH, decided to cooperate in a collaborative partnership with hospitals and a health care data consulting firm to get more information about the health care options available in their community. The Cincinnati Quality Initiative was formed with the goal of stimulating competition around quality and value in the health care market place. The 14 hospitals in the Cincinnati area were invited to participate in a 3-year program of investigation and analyses. The Initiative implemented the investigation in order to gather information that could be used to make health care choices for their employees. Hospitals that performed well over the 3-year period-those that improved over time-would then be selected by the Initiative. However, this selection process did not occur. Nevertheless, the 3-year evaluation proved useful because it generated valuable information about the health care options in Cincinnati and spurred competition among the hospitals. It also led to a dramatic reduction in health care costs for those hospitals that agreed to participate in the investigation.

  9. Down-regulation of glutaminase C in human hepatocarcinoma cell by diphenylarsinic acid, a degradation product of chemical warfare agents

    SciTech Connect

    Kita, Kayoko . E-mail: kkayoko@pharm.teikyo-u.ac.jp; Suzuki, Toshihide; Ochi, Takafumi

    2007-05-01

    In a poisonous incident in Kamisu, Japan, it is understood that diphenylarsinic acid (DPAA) was a critical contaminant of ground water. Most patients showed dysfunction of the central nervous system. To understand the overall mechanism of DPAA toxicity and to gain some insight into the application of a remedy specific for intoxication, the molecular target must be clarified. As an approach, a high throughput analysis of cell proteins in cultured human hepatocarcinoma HpG2 exposed to DPAA was performed by two-dimensional electrophoresis (2-DE). Four proteins, which were up- and down-regulated by exposure of cultured HepG2 cells to DPAA, were identified. They were chaperonin containing TCP-1 (CCT) beta subunit, aldehyde dehydrogenase 1 (ALDH1), ribosomal protein P0 and glutaminase C (GAC). Of these, GAC was the only protein that was down-regulated by DPAA exposure, and cellular expression levels were reduced by DPAA in a concentration- and time-dependent manner. Decrease in cellular GAC levels was accompanied by decreased activity of the enzyme, phosphate-activated glutaminase (PAG). Decreased expression of GAC by DPAA was also observed in human cervical carcinoma HeLa and neuroblastoma SH-SY5Y cells. By contrast, no significant changes in GAC protein expression were observed when cells were incubated with arsenite [iAs (III)] and trivalent dimethylarsinous acid [DMA (III)]. In the central nervous system, GAC plays a role in the production of the neurotransmitter glutamic acid. Selective inhibition of GAC expression by DPAA may be a cause of dysfunction of glutamatergic neuronal transmission and the resultant neurological impairments.

  10. Transcript profiling of early lateral root initiation.

    PubMed

    Himanen, Kristiina; Vuylsteke, Marnik; Vanneste, Steffen; Vercruysse, Steven; Boucheron, Elodie; Alard, Philippe; Chriqui, Dominique; Van Montagu, Marc; Inzé, Dirk; Beeckman, Tom

    2004-04-06

    At the onset of lateral root initiation in Arabidopsis thaliana, the phytohormone auxin activates xylem pole pericycle cells for asymmetric cell division. However, the molecular events leading from auxin to lateral root initiation are poorly understood, in part because the few responsive cells in the process are embedded in the root and are thus difficult to access. A lateral root induction system, in which most xylem pole pericycle cells were synchronously activated by auxin transport inhibition followed by auxin application, was used for microarray transcript profiling. Of 4,600 genes analyzed, 906 significantly differentially regulated genes were identified that could be grouped into six major clusters. Basically, three major patterns were discerned representing induced, repressed, and transiently expressed genes. Analysis of the coregulated genes, which were specific for each time point, provided new insight into the molecular regulation and signal transduction preceding lateral root initiation in Arabidopsis. The reproducible expression profiles during a time course allowed us to define four stages that precede the cell division in the pericycle. These early stages were characterized by G1 cell cycle block, auxin perception, and signal transduction, followed by progression over G1/S transition and G2/M transition. All these processes took place within 6 h after transfer from N-1-naphthylphthalamic acid to 1-naphthalene acetic acid. These results indicate that this lateral root induction system represents a unique synchronized system that allows the systematic study of the developmental program upstream of the cell cycle activation during lateral root initiation.

  11. Arsenic Metabolites, Including N-Acetyl-4-hydroxy-m-arsanilic Acid, in Chicken Litter from a Roxarsone-Feeding Study Involving 1600 Chickens.

    PubMed

    Yang, Zonglin; Peng, Hanyong; Lu, Xiufen; Liu, Qingqing; Huang, Rongfu; Hu, Bin; Kachanoski, Gary; Zuidhof, Martin J; Le, X Chris

    2016-07-05

    The poultry industry has used organoarsenicals, such as 3-nitro-4-hydroxyphenylarsonic acid (Roxarsone, ROX), to prevent disease and to promote growth. Although previous studies have analyzed arsenic species in chicken litter after composting or after application to agricultural lands, it is not clear what arsenic species were excreted by chickens before biotransformation of arsenic species during composting. We describe here the identification and quantitation of arsenic species in chicken litter repeatedly collected on days 14, 24, 28, 30, and 35 of a Roxarsone-feeding study involving 1600 chickens of two strains. High performance liquid chromatography separation with simultaneous detection by both inductively coupled plasma mass spectrometry and electrospray ionization tandem mass spectrometry provided complementary information necessary for the identification and quantitation of arsenic species. A new metabolite, N-acetyl-4-hydroxy-m-arsanilic acid (N-AHAA), was identified, and it accounted for 3-12% of total arsenic. Speciation analyses of litter samples collected from ROX-fed chickens on days 14, 24, 28, 30, and 35 showed the presence of N-AHAA, 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA), inorganic arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA(V)), dimethylarsinic acid (DMA(V)), and ROX. 3-AHPAA accounted for 3-19% of the total arsenic. Inorganic arsenicals (the sum of As(III) and As(V)) comprised 2-6% (mean 3.5%) of total arsenic. Our results on the detection of inorganic arsenicals, methylarsenicals, 3-AHPAA, and N-AHAA in the chicken litter support recent findings that ROX is actually metabolized by the chicken or its gut microbiome. The presence of the toxic metabolites in chicken litter is environmentally relevant as chicken litter is commonly used as fertilizer.

  12. Amino acid analyses of Apollo 14 samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Aue, W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

  13. Biodegradation of resin acid sodium salts

    Treesearch

    Richard W. Hemingway; H. Greaves

    1973-01-01

    The sodium salts of resin acids were readily degraded by microflora from two types of river water and from an activated sewage sludge. A lag phase with little or no resin acid salt degradation but rapid bacterial development occurred which was greatly extended by a decrease in incubation temperature. After this initial lag phase, the resin acid salts were rapidly...

  14. Amino acid analyses of Apollo 14 samples.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Aue, W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

    1972-01-01

    Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

  15. Initiation Chemistries in Hydrocarbon (Aut)Oxidation.

    PubMed

    Sandhiya, Lakshmanan; Zipse, Hendrik

    2015-09-28

    For the (aut)oxidation of toluene to benzyl hydroperoxide, benzyl alcohol, benzaldehyde, and benzoic acid, the thermochemical profiles for various radical-generating reactions have been compared. A key intermediate in all of these reactions is benzyl hydroperoxide, the heat of formation of which has been estimated by using results from CBS-QB3, G4, and G3B3 calculations. Homolytic O-O bond cleavage in this hydroperoxide is strongly endothermic and thus unlikely to contribute significantly to initiation processes. In terms of reaction enthalpies the most favorable initiation process involves bimolecular reaction of benzyl hydroperoxide to yield hydroxy and benzyloxy radicals along with water and benzaldehyde. The reaction enthalpy and free energy of this process is significantly more favorable than those for the unimolecular dissociation of known radical initiators, such as dibenzoylperoxide or dibenzylhyponitrite.

  16. Effect of acetic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    PubMed

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-09-01

    An integrated citric acid-methane fermentation process was proposed to solve the problem of extraction wastewater in citric acid fermentation process. Extraction wastewater was treated by anaerobic digestion and then recycled for the next batch of citric acid fermentation to eliminate wastewater discharge and reduce water resource consumption. Acetic acid as an intermediate product of methane fermentation was present in anaerobic digestion effluent. In this study, the effect of acetic acid on citric acid fermentation was investigated and results showed that lower concentration of acetic acid could promote Aspergillus niger growth and citric acid production. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) staining was used to quantify the activity of A. niger cells, and the results suggested that when acetic acid concentration was above 8 mM at initial pH 4.5, the morphology of A. niger became uneven and the part of the cells' activity was significantly reduced, thereby resulting in deceasing of citric acid production. Effects of acetic acid on citric acid fermentation, as influenced by initial pH and cell number in inocula, were also examined. The result indicated that inhibition by acetic acid increased as initial pH declined and was rarely influenced by cell number in inocula.

  17. Fatty acids - trans fatty acids

    USDA-ARS?s Scientific Manuscript database

    The data supporting a negative effect of dietary trans fatty acids on cardiovascular disease risk is consistent. The primary dietary sources of trans fatty acids include partially hydrogenated fat and rudiment fat. The adverse effect of trans fatty acids on plasma lipoprotein profiles is consisten...

  18. Initial blood storage experiment

    NASA Technical Reports Server (NTRS)

    Surgenor, Douglas MACN.

    1988-01-01

    The design of the Initial Blood Storage Experiment (IBSE) was based upon a carefully controlled comparison between identical sets of human blood cell suspensions - red cells, white cell, and platelets - one set of which was transported aboard the Columbia on a 6 day 11 hour mission, and the other held on the ground. Both sets were carried inside stainless steel dewars within specially fabricated flight hardware. Individual bags of cell suspensions were randomly assigned with respect to ground vs orbit status, dewar chamber, and specific location within the dewar. To foster optimal preservation, each cell type was held under specific optimal conditions of pH, ionic strength, solute concentration, gas tension, and temperature. An added variable in this initial experiment was provided by the use of three different polymer/plasticizer formulations for the sealed bags which held the blood cells. At termination of the experiment, aliquots of the suspensions, identified only by code, were distributed to be assayed. Assays were selected to constitute a broad survey of cellular properties and thereby maximize the chances of detection of gravitational effects. A total of 74 different outcome measurements were reported for statistical analysis. When the measurements were completed, the results were entered into the IBSE data base, at which time the data were matched with the original blood bag numbers to determine their status with respect to polymer/plasticizer type, orbit status (orbit or ground), and storage position within the experimental hardware. The data were studied by analysis of variance. Initially, type of bag and orbital status were main factors; later more detailed analyses were made on specific issues such as position in the hardware and specific plastic. If the analysis of variance indicated a statistical significance at the 5 percent level the corresponding p-value was reported.

  19. Through bulkhead initiator studies

    SciTech Connect

    Begeal, D.R.

    1997-03-01

    This report describes recent work done to demonstrate feasibility of a fail-safe Through Bulkhead Initiator with minimum dimensions and suitable for use in cyclical thermal environments. Much of the ground work for a fail-safe TBI was previously done by A.C. Schwartz. This study is an expansion of Schwartz`s work to evaluate devices with bulkheads of 304 stainless steel and Inconel 718; explosive donors of PETN, BNCP, and a 0.005 inch thick steel flying plate donor traveling at 2.6 mm/{micro}s; and explosive acceptors of PETN and BNCP. Bulkhead thickness were evaluated in the range of 0.040 to 0.180 inch. The explosive acceptors initiated a small HMX pellet to drive a 0.005 inch thick steel flying plate, and VISAR histories of the HMX-driven flying plates were the measure of acceptable performance. A companion set of samples used a PMMA acceptor to measure the particle velocities at the bulkhead/PMMA interface with VISAR. These data were used to compute the input pressure to the acceptor explosives in an attempt to measure initiation threshold. Unfortunately, the range of bulkhead thicknesses tested did not give any failures, thus the threshold was not determined. It was found that either explosive or the flying plate would perform as a TBI in the bulkhead thickness range tested. The optimum TBI is about 0.060 inches thick, and steel bulkheads seem to be more structurally sound than those made of Inconel. That is, cross section views of the Inconel bulkheads showed it to be more prone to stress cracking than was the 304 stainless steel. Both PETN and BNCP showed good performance when tested at {minus}65 F following thermal cycling of {minus}65 F to +165 F. Analysis of the TBI function times showed that BNCP acceptor explosives were undergoing the classical deflagration to detonation process. The PETN acceptors were undergoing prompt detonation.

  20. Hanford tanks initiative plan

    SciTech Connect

    McKinney, K.E.

    1997-07-01

    Abstract: The Hanford Tanks Initiative (HTI) is a five-year project resulting from the technical and financial partnership of the U.S. Department of Energy`s Office of Waste Management (EM-30) and Office of Science and Technology Development (EM-50). The HTI project accelerates activities to gain key technical, cost performance, and regulatory information on two high-level waste tanks. The HTI will provide a basis for design and regulatory decisions affecting the remainder of the Tank Waste Remediation System`s tank waste retrieval Program.

  1. Advanced Monitoring systems initiative

    SciTech Connect

    R.J. Venedam; E.O. Hohman; C.F. Lohrstorfer; S.J. Weeks; J.B. Jones; W.J. Haas

    2004-09-30

    The Advanced Monitoring Systems Initiative (AMSI) actively searches for promising technologies and aggressively moves them from the research bench into DOE/NNSA end-user applications. There is a large unfulfilled need for an active element that reaches out to identify and recruit emerging sensor technologies into the test and evaluation function. Sensor research is ubiquitous, with the seeds of many novel concepts originating in the university systems, but at present these novel concepts do not move quickly and efficiently into real test environments. AMSI is a widely recognized, self-sustaining ''business'' accelerating the selection, development, testing, evaluation, and deployment of advanced monitoring systems and components.

  2. UNLV Nuclear Hydrogen Initiative

    SciTech Connect

    Hechanova, Anthony E.; Johnson, Allen; O'Toole, Brendan; Trabia, Mohamed; Peterson, Per

    2012-10-25

    Evaluation of the Crack growth rate (CGR) of Alloy 617 and Alloy 276 under constant K at ambient temperature has been completed. Creep deformation of Alloy 230 at different temperature range and load level has been completed and heat to heat variation has been noticed. Creep deformation study of Alloy 276 has been completed under an applied initial stress level of 10% of yield stress at 950ºC. The grain size evaluation of the tested creep specimens of Alloy 276 has been completed.

  3. Human Research Initiative (HRI)

    NASA Technical Reports Server (NTRS)

    Motil, Brian

    2003-01-01

    A code U initiative starting in the FY04 budget includes specific funding for 'Phase Change' and 'Multiphase Flow Research' on the ISS. NASA GRC developed a concept for two facilities based on funding/schedule constraints: 1) Two Phase Flow Facility (TphiFFy) which assumes integrating into FIR; 2) Contact Line Dynamics Experiment Facility (CLiDE) which assumes integration into MSG. Each facility will accommodate multiple experiments conducted by NRA selected PIs with an overall goal of enabling specific NASA strategic objectives. There may also be a significant ground-based component.

  4. Stirling to Flight Initiative

    NASA Technical Reports Server (NTRS)

    Hibbard, Kenneth E.; Mason, Lee S.; Ndu, Obi; Smith, Clayton; Withrow, James P.

    2016-01-01

    Flight (S2F) initiative with the objective of developing a 100-500 We Stirling generator system. Additionally, a different approach is being devised for this initiative to avoid pitfalls of the past, and apply lessons learned from the recent ASRG experience. Two key aspects of this initiative are a Stirling System Technology Maturation Effort, and a Surrogate Mission Team (SMT) intended to provide clear mission pull and requirements context. The S2F project seeks to lead directly into a DOE flight system development of a new SRG. This paper will detail the proposed S2F initiative, and provide specifics on the key efforts designed to pave a forward path for bringing Stirling technology to flight.

  5. COTS Initiative Panel Discussion

    NASA Image and Video Library

    2013-11-13

    NASA Administrator Charles Bolden, left, presents NASA's Group Achievement Award to (L-R) Frank Culbertson, Executive Vice President and General Manager, Orbital Sciences Advanced Programs Group,at NASA Headquarters in Washington on Thursday, November 13, 2013. Culbertson received the award for outstanding contributions and innovative accomplishments in the completion of the Commercial Orbital Transportation Services (COTS) initiative. Through COTS, NASA's partners Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp., developed new U.S. rockets and spacecraft, launched from U.S. soil, capable of transporting cargo to low-Earth orbit and the International Space Station. Photo Credit: (NASA/Jay Westcott)

  6. COTS Initiative Panel Discussion

    NASA Image and Video Library

    2013-11-13

    NASA Administrator Charles Bolden, left, presents NASA's Group Achievement Award to Gwynne Shotwell, President, SpaceX, at NASA Headquarters in Washington on Thursday, November 13, 2013. Shotwell received the award for outstanding contributions and innovative accomplishments in the completion of the Commercial Orbital Transportation Services (COTS) initiative. Through COTS, NASA's partners Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp., developed new U.S. rockets and spacecraft, launched from U.S. soil, capable of transporting cargo to low-Earth orbit and the International Space Station. Photo Credit: (NASA/Jay Westcott)

  7. Initiation of slug flow

    SciTech Connect

    Hanratty, T.J.; Woods, B.D.

    1995-12-31

    The initiation of slug flow in a horizontal pipe can be predicted either by considering the stability of a slug or by considering the stability of a stratified flow. Measurements of the shedding rate of slugs are used to define necessary conditions for the existence of a slug. Recent results show that slugs develop from an unstable stratified flow through the evolution of small wavelength waves into large wavelength waves that have the possibility of growing to form a slug. The mechanism appears to be quite different for fluids with viscosities close to water than for fluids with large viscosities (20 centipoise).

  8. Feedback stabilization initiative

    SciTech Connect

    1997-06-01

    Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes.

  9. Endoplasmic reticulum stress induced by tunicamycin increases resistin messenger ribonucleic acid through the pancreatic endoplasmic reticulum eukaryotic initiation factor 2α kinase-activating transcription factor 4-CAAT/enhancer binding protein-α homologous protein pathway in THP-1 human monocytes.

    PubMed

    Hamada, Junpei; Onuma, Hiroshi; Ochi, Fumihiro; Hirai, Hiroki; Takemoto, Koji; Miyoshi, Akiko; Matsushita, Manami; Kadota, Yuko; Ohashi, Jun; Kawamura, Ryoichi; Takata, Yasunori; Nishida, Wataru; Hashida, Seiichi; Ishii, Eiichi; Osawa, Haruhiko

    2016-05-01

    Resistin, secreted from adipocytes, causes insulin resistance in mice. In humans, the resistin gene is mainly expressed in monocytes and macrophages. Tunicamycin is known to induce endoplasmic reticulum (ER) stress, and reduce resistin gene expression in 3T3-L1 mouse adipocytes. The aim of the present study was to examine whether ER stress affects resistin gene expression in human monocytes. The relationship between resistin messenger ribonucleic acid (mRNA) and ER stress markers mRNA was analyzed by reverse transcription polymerase chain reaction in isolated monocytes of 30 healthy volunteers. The effect of endotoxin/lipopolysaccharides or tunicamycin on resistin gene expression was analyzed in THP-1 human monocytes. Signaling pathways leading to resistin mRNA were assessed by the knockdown using small interfering RNA or overexpression of key molecules involved in unfolded protein response. Resistin mRNA was positively associated with immunoglobulin heavy chain-binding protein (BiP) or CAAT/enhancer binding protein-α homologous protein (CHOP) mRNA in human isolated monocytes. In THP-1 cells, lipopolysaccharides increased mRNA of BiP, pancreatic endoplasmic reticulum eukaryotic initiation factor 2α kinase (PERK) and CHOP, as well as resistin. Tunicamycin also increased resistin mRNA. This induction appeared to be dose- and time-dependent. Tunicamycin-induced resistin mRNA was inhibited by chemical chaperone, 4-phenylbutyric acid. The knockdown of either PERK, activating transcription factor 4 (ATF4) or CHOP reduced tunicamycin-induced resistin mRNA. Conversely, overexpression of ATF4 or CHOP increased resistin mRNA. Endoplasmic reticulum stress induced by tunicamycin increased resistin mRNA through the PERK-ATF4-CHOP pathway in THP-1 human monocytes. ER stress could lead to insulin resistance through enhanced resistin gene expression in human monocytes.

  10. Microbial degradation of poly(amino acid)s.

    PubMed

    Obst, Martin; Steinbüchel, Alexander

    2004-01-01

    Natural poly(amino acid)s are a group of poly(ionic) molecules (ionomers) with various biological functions and putative technical applications and play, therefore, an important role both in nature and in human life. Because of their biocompatibility and their synthesis from renewable resources, poly(amino acid)s may be employed for many different purposes covering a broad spectrum of medical, pharmaceutical, and personal care applications as well as the domains of agriculture and of environmental applications. Biodegradability is one important advantage of naturally occurring poly(amino acid)s over many synthetic polymers. The intention of this review is to give an overview about the enzyme systems catalyzing the initial steps in poly(amino acid) degradation. The focus is on the naturally occurring poly(amino acid)s cyanophycin, poly(epsilon-L-lysine) and poly(gamma-glutamic acid); but biodegradation of structurally related synthetic polyamides such as poly(aspartic acid) and nylons, which are known from various technical applications, is also included.

  11. Combat Wound Initiative program.

    PubMed

    Stojadinovic, Alexander; Elster, Eric; Potter, Benjamin K; Davis, Thomas A; Tadaki, Doug K; Brown, Trevor S; Ahlers, Stephen; Attinger, Christopher E; Andersen, Romney C; Burris, David; Centeno, Jose; Champion, Hunter; Crumbley, David R; Denobile, John; Duga, Michael; Dunne, James R; Eberhardt, John; Ennis, William J; Forsberg, Jonathan A; Hawksworth, Jason; Helling, Thomas S; Lazarus, Gerald S; Milner, Stephen M; Mullick, Florabel G; Owner, Christopher R; Pasquina, Paul F; Patel, Chirag R; Peoples, George E; Nissan, Aviram; Ring, Michael; Sandberg, Glenn D; Schaden, Wolfgang; Schultz, Gregory S; Scofield, Tom; Shawen, Scott B; Sheppard, Forest R; Stannard, James P; Weina, Peter J; Zenilman, Jonathan M

    2010-07-01

    The Combat Wound Initiative (CWI) program is a collaborative, multidisciplinary, and interservice public-private partnership that provides personalized, state-of-the-art, and complex wound care via targeted clinical and translational research. The CWI uses a bench-to-bedside approach to translational research, including the rapid development of a human extracorporeal shock wave therapy (ESWT) study in complex wounds after establishing the potential efficacy, biologic mechanisms, and safety of this treatment modality in a murine model. Additional clinical trials include the prospective use of clinical data, serum and wound biomarkers, and wound gene expression profiles to predict wound healing/failure and additional clinical patient outcomes following combat-related trauma. These clinical research data are analyzed using machine-based learning algorithms to develop predictive treatment models to guide clinical decision-making. Future CWI directions include additional clinical trials and study centers and the refinement and deployment of our genetically driven, personalized medicine initiative to provide patient-specific care across multiple medical disciplines, with an emphasis on combat casualty care.

  12. Precision flyer initiator

    DOEpatents

    Frank, A.M.; Lee, R.S.

    1998-05-26

    A precision flyer initiator forms a substantially spherical detonation wave in a high explosive (HE) pellet. An explosive driver, such as a detonating cord, a wire bridge circuit or a small explosive, is detonated. A flyer material is sandwiched between the explosive driver and an end of a barrel that contains an inner channel. A projectile or ``flyer`` is sheared from the flyer material by the force of the explosive driver and projected through the inner channel. The flyer than strikes the HE pellet, which is supported above a second end of the barrel by a spacer ring. A gap or shock decoupling material delays the shock wave in the barrel from predetonating the HE pellet before the flyer. A spherical detonation wave is formed in the HE pellet. Thus, a shock wave traveling through the barrel fails to reach the HE pellet before the flyer strikes the HE pellet. The precision flyer initiator can be used in mining devices, well-drilling devices and anti-tank devices. 10 figs.

  13. Precision flyer initiator

    DOEpatents

    Frank, Alan M.; Lee, Ronald S.

    1998-01-01

    A precision flyer initiator forms a substantially spherical detonation wave in a high explosive (HE) pellet. An explosive driver, such as a detonating cord, a wire bridge circuit or a small explosive, is detonated. A flyer material is sandwiched between the explosive driver and an end of a barrel that contains an inner channel. A projectile or "flyer" is sheared from the flyer material by the force of the explosive driver and projected through the inner channel. The flyer than strikes the HE pellet, which is supported above a second end of the barrel by a spacer ring. A gap or shock decoupling material delays the shock wave in the barrel from predetonating the HE pellet before the flyer. A spherical detonation wave is formed in the HE pellet. Thus, a shock wave traveling through the barrel fails to reach the HE pellet before the flyer strikes the HE pellet. The precision flyer initiator can be used in mining devices, well-drilling devices and anti-tank devices.

  14. Global cancer research initiative

    PubMed Central

    Love, Richard R

    2010-01-01

    Cancer is an increasing problem for low- and middle-income countries undergoing an epidemiologic transition from dominantly acute communicable disease to more frequent chronic disease with increased public health successes in the former domain. Progress against cancer in high-income countries has been modest and has come at enormous expense. There are several well-conceived global policy and planning initiatives which, with adequate political will, can favorably impact the growing global cancer challenges. Most financial resources for cancer, however, are spent on diagnosis and management of patients with disease in circumstances where specific knowledge about effective approaches is significantly limited, and the majority of interventions, other than surgery, are not cost-effective in resource-limited countries by global standards. In summary, how to intervene effectively on a global scale for the majority of citizens who develop cancer is poorly defined. In contrast to technology-transfer approaches, markedly increased clinical research activities are more likely to benefit cancer sufferers. In these contexts, a global cancer research initiative is proposed, and mechanisms for realizing such an effort are suggested. PMID:21188101

  15. Strategic defense initiative

    SciTech Connect

    Nichols, J.P.

    1985-01-01

    The Engineering Technology Division has a leading role, including that of program management, in a major new programmatic thrust of the Oak Ridge National Laboratory that is in support of the national Strategic Defense Initiative (SDI). It is appropriate for the Laboratory to become significantly involved in the program because several of the most promising SDI technologies are in areas for which ORNL (together with Y-12 and K-25) have strong capabilities and significant resources. The initial ORNL work in support of the SDI program is focused on three technologies in which ORNL has extensive experience and traditionally strong research and development programs: (1) space nuclear power, (2) flywheel energy storage, and (3) neutral particle beams. The space nuclear program will utilize our capabilities in areas such as refractory materials, high-temperature alkali metal systems, shielding, and instrumentation. Space nuclear reactors capable of supplying multimegawatt levels of electrical power on a continuous and long-term basis are envisioned to be required for a variety of SDI surveillance satellites and space-borne weapons platforms. The feasibility of an alkali metal Rankine power conversion cycle, which has promise of providing high power with a very low system mass, is planned for study.

  16. Initiatives for proliferation prevention

    SciTech Connect

    1997-04-01

    Preventing the proliferation of weapons of mass destruction is a central part of US national security policy. A principal instrument of the Department of Energy`s (DOE`s) program for securing weapons of mass destruction technology and expertise and removing incentives for scientists, engineers and technicians in the newly independent states (NIS) of the former Soviet Union to go to rogue countries or assist terrorist groups is the Initiatives for Proliferation Prevention (IPP). IPP was initiated pursuant to the 1994 Foreign Operations Appropriations Act. IPP is a nonproliferation program with a commercialization strategy. IPP seeks to enhance US national security and to achieve nonproliferation objectives by engaging scientists, engineers and technicians from former NIS weapons institutes; redirecting their activities in cooperatively-developed, commercially viable non-weapons related projects. These projects lead to commercial and economic benefits for both the NIS and the US IPP projects are funded in Russian, Ukraine, Kazakhstan and Belarus. This booklet offers an overview of the IPP program as well as a sampling of some of the projects which are currently underway.

  17. Brazilian Nanotechnology Initiative

    NASA Astrophysics Data System (ADS)

    Fazzio, Adalberto

    2015-03-01

    In Brazil there is intense research activity in nanotechnology, most of these developed in universities and research institutes. The Brazilian Nanotechnology Initiative (BNI) aims to integrate government actions to promote the competitiveness of the Brazilian industry. This initiative is founded on support for research and development in the laboratories of the National Laboratories for Nanotechnology (SisNANO), starting from an improvement in infrastructure and opening of laboratories for users of academia and business, promoting interaction and transfer knowledge between academia and business. Country currently has 26 thematic networks of nanotechnology, 16 -Virtual-National Institutes of Technology, seven National- Laboratories and 18 Associate Laboratories, which comprise the SisNANO. Seeking to expand and share governance with other government actors, the Interministries Committee for Nanotechnology was set up, composed of 10 ministries, and has the task of coordinating the entire program of the Federal Government Nanotechnology.Cooperation activities are an important part of BNI. Currently Brazil has cooperation programs with U.S., China, Canada and European Union among others. Recently, Brazil decided to join the European NanoReg program where 60 research groups are joining efforts to provide protocols and standards that can help regulatory agencies and governments.

  18. Evaluation of clastogenicity of formic acid, acetic acid and lactic acid on cultured mammalian cells.

    PubMed

    Morita, T; Takeda, K; Okumura, K

    1990-03-01

    Using Chinese hamster ovary K1 cells, chromosomal aberration tests were carried out with formic acid, acetic acid and lactic acid, and the relationship between the pH of the medium and the clastogenic activity was examined. The medium used was Ham's F12 supplemented with 17 mM NaHCO3 and 10% fetal calf serum. All of these acids induced chromosomal aberrations at the initial pH of ca. 6.0 or below (about 10-14 mM of each acid) both with and without S9 mix. Exposure of cells to about pH 5.7 or below (about 12-16 mM of each acid) was found to be toxic. When the culture medium was first acidified with each of these acids and then neutralized to pH 6.4 or pH 7.2 with NaOH, no clastogenic activity was observed. Using F12 medium supplemented with 34 mM NaHCO3 as a buffer, no clastogenic activity was observed at doses up to 25 mM of these acids (initial pH 5.8-6.0). However, it was found that about 10% of the cells had aberrations at pH 5.7 or below (27.5-32.5 mM of each acid). Furthermore, when 30 mM HEPES was used as a buffer, chromosomal aberrations were not induced at doses up to 20 mM formic acid and acetic acid (initial pH 7.0-7.1), and at doses up to 30 mM lactic acid (initial pH 6.6). In the initial pH range of 6.4-6.7 (25-32.5 mM of each acid), chromosomal aberrations were observed. The above results show that these acids themselves are non-clastogenic, and the pseudo-positive reactions attributable to non-physiological pH could be eliminated by either neutralization of the treatment medium or enhancement of the buffering ability.

  19. Quality initiative at ESO

    NASA Astrophysics Data System (ADS)

    Rupprecht, Gero; Arsenault, Robin; Hanuschik, Reinhard; Kraus, Maximilian; Sivera, Paola; Tromp, Arnout; Verzichelli, Gianluca

    2016-08-01

    An initiative is under way at ESO Headquarters to optimise operations, in particular in the engineering, technical and associated management areas. A systematic approach to strengthen the operating processes is in preparation, starting with a mapping of the extensive existing process network. Processes identified as sufficiently important and complex to merit an in-depth analysis will be properly specified and their implementation optimised to strike a sensible balance between organisational overhead (documentation) and efficiency. By applying methods and tools tried and tested in industry we expect to achieve a more unified approach to address recurrent tasks. This will enable staff to concentrate more on new challenges and improvement and avoid spending effort on issues already resolved in the past.

  20. Instrumented Pipeline Initiative

    SciTech Connect

    Thomas Piro; Michael Ream

    2010-07-31

    This report summarizes technical progress achieved during the cooperative agreement between Concurrent Technologies Corporation (CTC) and U.S. Department of Energy to address the need for a for low-cost monitoring and inspection sensor system as identified in the Department of Energy (DOE) National Gas Infrastructure Research & Development (R&D) Delivery Reliability Program Roadmap.. The Instrumented Pipeline Initiative (IPI) achieved the objective by researching technologies for the monitoring of pipeline delivery integrity, through a ubiquitous network of sensors and controllers to detect and diagnose incipient defects, leaks, and failures. This report is organized by tasks as detailed in the Statement of Project Objectives (SOPO). The sections all state the objective and approach before detailing results of work.

  1. Materials Genome Initiative

    NASA Technical Reports Server (NTRS)

    Vickers, John

    2015-01-01

    The Materials Genome Initiative (MGI) project element is a cross-Center effort that is focused on the integration of computational tools to simulate manufacturing processes and materials behavior. These computational simulations will be utilized to gain understanding of processes and materials behavior to accelerate process development and certification to more efficiently integrate new materials in existing NASA projects and to lead to the design of new materials for improved performance. This NASA effort looks to collaborate with efforts at other government agencies and universities working under the national MGI. MGI plans to develop integrated computational/experimental/ processing methodologies for accelerating discovery and insertion of materials to satisfy NASA's unique mission demands. The challenges include validated design tools that incorporate materials properties, processes, and design requirements; and materials process control to rapidly mature emerging manufacturing methods and develop certified manufacturing processes

  2. [Advanced Composites Technology Initiatives

    NASA Technical Reports Server (NTRS)

    Julian, Mark R.

    2002-01-01

    This final report closes out the W02 NASA Grant #NCC5-646. The FY02 grant for advanced technology initiatives through the Advanced Composites Technology Institute in Bridgeport, WV, at the Robert C. Byrd Institute (RCBI) Bridgeport Manufacturing Technology Center, is complete; all funding has been expended. RCBI continued to expand access to technology; develop and implement a workforce-training curriculum; improve material development; and provide prototyping and demonstrations of new and advanced composites technologies for West Virginia composites firms. The FY 02 efforts supported workforce development, technical training and the HST development effort of a super-lightweight composite carrier prototype and expanded the existing technical capabilities of the growing aerospace industry across West Virginia to provide additional support for NASA missions. Additionally, the Composites Technology and Training Center was awarded IS0 9001 - 2000 certification and Cleanroom Class 1000 certification during this report period.

  3. Breckinridge Project, initial effort

    SciTech Connect

    None, None

    1982-09-01

    Report III, Volume 1 contains those specifications numbered A through J, as follows: General Specifications (A); Specifications for Pressure Vessels (C); Specifications for Tanks (D); Specifications for Exchangers (E); Specifications for Fired Heaters (F); Specifications for Pumps and Drivers (G); and Specifications for Instrumentation (J). The standard specifications of Bechtel Petroleum Incorporated have been amended as necessary to reflect the specific requirements of the Breckinridge Project, and the more stringent specifications of Ashland Synthetic Fuels, Inc. These standard specifications are available to the Initial Effort (Phase Zero) work performed by all contractors and subcontractors. Report III, Volume 1 also contains the unique specifications prepared for Plants 8, 15, and 27. These specifications will be substantially reviewed during Phase I of the project, and modified as necessary for use during the engineering, procurement, and construction of this project.

  4. Congress initiates science study

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    The U.S. House of Representatives announced in October a year-long study to review the nation's science and technology policy and the government's role in funding scientific research. The Science Policy Study, led by Rep. Vernon Ehlers (R-MI), is the first comprehensive review by Congress since 1985—a time when the Cold War still was being fought and the Internet was largely unknown.At a workshop to discuss the initiative, House Science Committee Chair James Sensenbrenner, Jr., told about 30 scientists and policy experts that the challenge is “to develop a new, sensible, coherent long-range science and technology policy, including a review of our nation's science and math education programs.”

  5. COTS Initiative Panel Discussion

    NASA Image and Video Library

    2013-11-13

    L-R: Alan Lindenmoyer, Manager of Commercial Crew and Cargo Program, NASA; Gwynne Shotwell, President, SpaceX; Frank Culbertson, Executive Vice President and General Manager, Orbital Sciences Advanced Programs Group; Frank Slazer, Vice President of Space Systems, Aerospace Industries Association and Phil McAlister, Director of Commercial Spaceflight Development at NASA, participate in a panel discussion on the Commercial Orbital Transportation Services (COTS) initiative at NASA Headquarters in Washington on Wednesday, November 13, 2013. Through COTS, NASA's partners Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp., developed new U.S. rockets and spacecraft, launched from U.S. soil, capable of transporting cargo to low-Earth orbit and the International Space Station. Photo Credit: (NASA/Jay Westcott)

  6. The Knowledge Stealing Initiative?

    NASA Technical Reports Server (NTRS)

    Goshorn, Larry

    2005-01-01

    I have the honor of being on the Academy of Program and Project Leadership (APPL) Knowledge Sharing Feedback and Assessment Team (FAA), and as such, I am privileged to receive the feedback written by many of you as attendees of the Project Management (PM) Master s Forums. It is the intent of the FAA Team and APPL leadership to use this feedback as a tool for continuous program improvement. As a retired (sort of) PM in the payload contracting industry, I'm a big supporter of NASA s Knowledge Sharing Initiative (KSI), especially the Master's Forums. I really enjoy participating in them. Unfortunately I had to miss the 8th forum in Pasadena this past Spring, but I did get the feedback package for the Assessment Team work. So here I was, reviewing twelve pages of comments, reflections, learning notes and critiques from attendees of the 8th forum.

  7. Biodegradation of Cyanuric Acid

    PubMed Central

    Saldick, Jerome

    1974-01-01

    Cyanuric acid biodegrades readily under a wide variety of natural conditions, and particularly well in systems of either low or zero dissolved-oxygen level, such as anaerobic activated sludge and sewage, soils, muds, and muddy streams and river waters, as well as ordinary aerated activated sludge systems with typically low (1 to 3 ppm) dissolved-oxygen levels. Degradation also proceeds in 3.5% sodium chloride solution. Consequently, there are degradation pathways widely available for breaking down cyanuric acid discharged in domestic effluents. The overall degradation reaction is merely a hydrolysis; CO2 and ammonia are the initial hydrolytic breakdown products. Since no net oxidation occurs during this breakdown, biodegradation of cyanuric acid exerts no primary biological oxygen demand. However, eventual nitrification of the ammonia released will exert its usual biological oxygen demand. PMID:4451360

  8. Green Power Initiative

    SciTech Connect

    Butler, Patrick Barry

    2013-01-28

    National energy policy supports the gathering of more detailed and authoritative data on the introduction of renewable bio-based fuels into new and existing district energy systems via the application of biomass gasification. The University of Iowa developed a biomass-fueled, university-scale steam generation system based on biomass gasification technologies. The system serves as a state-of-the-art research and educational facility in the emerging application of gasification in steam generation. The facility, which includes a smaller down-draft gasifier and a larger multi-stage biomass boiler, was designed to operate primarily on wood-based fuels, but has provisions for testing other biomass fuel sources produced within a 100-mile radius, providing enough flexibility to meet the fluctuating local supply of biomass from industry and Midwest agriculture. The equipment was installed in an existing, staffed facility. The down-draft gasifier unit is operated by College of Engineering staff and students, under the direct technical supervision of qualified Utilities plant staff. The Green Power Initiative also includes a substantial, innovative educational component. In addition to an onsite, graduate-level research program in biomass fuels, the investigators have integrated undergraduate and graduate level teaching – through classroom studies and experiential learning – and applied research into a biomass-based, university-scale, functioning power plant. University of Iowa is unique in that it currently has multiple renewable energy technologies deployed, including significant biomass combustion (oat hulls) at its Main Power Plant and a new reciprocating engine based renewable district energy system. This project complements and supports the national energy policy and State of Iowa initiatives in ethanol and biodiesel. Byproducts of ethanol and biodiesel processes (distiller grains) as well as industry residues (oat hulls, wood chips, construction and demolition

  9. MONTANA PALLADIUM RESEARCH INITIATIVE

    SciTech Connect

    Peters, John; McCloskey, Jay; Douglas, Trevor; Young, Mark; Snyder, Stuart; Gurney, Brian

    2012-05-09

    Project Objective: The overarching objective of the Montana Palladium Research Initiative is to perform scientific research on the properties and uses of palladium in the context of the U.S. Department of Energy's Hydrogen, Fuel Cells and Infrastructure Technologies Program. The purpose of the research will be to explore possible palladium as an alternative to platinum in hydrogen-economy applications. To achieve this objective, the Initiatives activities will focus on several cutting-edge research approaches across a range of disciplines, including metallurgy, biomimetics, instrumentation development, and systems analysis. Background: Platinum-group elements (PGEs) play significant roles in processing hydrogen, an element that shows high potential to address this need in the U.S. and the world for inexpensive, reliable, clean energy. Platinum, however, is a very expensive component of current and planned systems, so less-expensive alternatives that have similar physical properties are being sought. To this end, several tasks have been defined under the rubric of the Montana Palladium Research Iniative. This broad swath of activities will allow progress on several fronts. The membrane-related activities of Task 1 employs state-of-the-art and leading-edge technologies to develop new, ceramic-substrate metallic membranes for the production of high-purity hydrogen, and develop techniques for the production of thin, defect-free platinum group element catalytic membranes for energy production and pollution control. The biomimetic work in Task 2 explores the use of substrate-attached hydrogen-producing enzymes and the encapsulation of palladium in virion-based protein coats to determine their utility for distributed hydrogen production. Task 3 work involves developing laser-induced breakdown spectroscopy (LIBS) as a real-time, in situ diagnostic technique to characterize PGEs nanoparticles for process monitoring and control. The systems engineering work in task 4 will

  10. Breckinridge Project, initial effort

    SciTech Connect

    1982-01-01

    Report IV, Volume 5, provides descriptions, data, and drawings pertaining to Cryogenic Hydrogen Purification (Plant 8), Sour Water Treating (Plant 9), and the Sulfur Plant (Plant 10). Cryogenic Hydrogen Purification (Plant 8) purifies the purge gas stream from the Gas Plant (Plant 7, described in Report IV, Volume 4) to a 93% purity hydrogen product. Sour Water Treating (Plant 9) removes free ammonia and acid gases from sour water and separates them to recover a high quality anhydrous ammonia product. The Sulfur Plant (Plant 10) recovers, as a saleable liquid product, approximately 95% of the sulfur in feed streams from the Gas Plant (Plant 7, described in Report IV, Volume 4), Sour Water Treating (Plant 9), Gasification and Purification (Plant 12, described in Report IV, Volume 6), and Stack Gas Scrubbing (Plant 35, described in Report V, Volume 3). The following information is included for each of the three plants described in this volume: a description of the plant's process design, including the utility balance, catalysts and chemicals usage, and a process flow diagram; an equipment list, including item numbers and descriptions; data sheets and sketches for major plant components; and pertinent engineering drawings. An appendix contains: an overall site plan showing the locations of all plants; and the symbols and legend for the piping and instrument diagrams included in this volume.

  11. Effect of plasma homocysteine level and urinary monomethylarsonic acid on the risk of arsenic-associated carotid atherosclerosis

    SciTech Connect

    Wu, M.-M.; Chiou, H.-Y. . E-mail: hychiou@tmu.edu.tw; Hsueh, Y.-M.; Hong, C.-T.; Su, C.-L.; Chang, S.-F.; Huang, W.-L.; Wang, H.-T.; Wang, Y.-H.; Hsieh, Y.-C.; Chen, C.-J.

    2006-10-01

    Arsenic-contaminated well water has been shown to increase the risk of atherosclerosis. Because of involving S-adenosylmethionine, homocysteine may modify the risk by interfering with the biomethylation of ingested arsenic. In this study, we assessed the effect of plasma homocysteine level and urinary monomethylarsonic acid (MMA{sup V}) on the risk of atherosclerosis associated with arsenic. In total, 163 patients with carotid atherosclerosis and 163 controls were studied. Lifetime cumulative arsenic exposure from well water for study subjects was measured as index of arsenic exposure. Homocysteine level was determined by high-performance liquid chromatography (HPLC). Proportion of MMA{sup V} (MMA%) was calculated by dividing with total arsenic species in urine, including arsenite, arsenate, MMA{sup V}, and dimethylarsinic acid (DMA{sup V}). Results of multiple linear regression analysis show a positive correlation of plasma homocysteine levels to the cumulative arsenic exposure after controlling for atherosclerosis status and nutritional factors (P < 0.05). This correlation, however, did not change substantially the effect of arsenic exposure on the risk of atherosclerosis as analyzed in a subsequent logistic regression model. Logistic regression analyses also show that elevated plasma homocysteine levels did not confer an independent risk for developing atherosclerosis in the study population. However, the risk of having atherosclerosis was increased to 5.4-fold (95% CI, 2.0-15.0) for the study subjects with high MMA% ({>=}16.5%) and high homocysteine levels ({>=}12.7 {mu}mol/l) as compared to those with low MMA% (<9.9%) and low homocysteine levels (<12.7 {mu}mol/l). Elevated homocysteinemia may exacerbate the formation of atherosclerosis related to arsenic exposure in individuals with high levels of MMA% in urine.

  12. A biological indicator of inorganic arsenic exposure using the sum of urinary inorganic arsenic and monomethylarsonic acid concentrations

    PubMed Central

    Hata, Akihisa; Kurosawa, Hidetoshi; Endo, Yoko; Yamanaka, Kenzo; Fujitani, Noboru; Endo, Ginji

    2016-01-01

    Objectives: The sum of urinary inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) concentrations is used for the biological monitoring of occupational iAs exposure. Although DMA is a major metabolite of iAs, it is an inadequate index because high DMA levels are present in urine after seafood consumption. We estimated the urinary iAs+MMA concentration corresponding to iAs exposure. Methods: We used data from two arsenic speciation analyses of urine samples from 330 Bangladeshi with oral iAs exposure and 172 Japanese workers without occupational iAs exposure using high-performance liquid chromatography with inductively coupled plasma mass spectrometry. Results: iAs, MMA, and DMA, but not arsenobetaine (AsBe), were detected in the urine of the Bangladeshi subjects. The correlation between iAs+MMA+DMA and iAs+MMA was obtained as log (iAs+MMA) = 1.038 log (iAs+MMA+DMA) -0.658. Using the regression formula, the iAs+MMA value was calculated as 2.15 and 7.5 μg As/l, corresponding to 3 and 10 μg As/m3 of exposures, respectively. In the urine of the Japanese workers, arsenic was mostly excreted as AsBe. We used the 95th percentile of iAs+MMA (12.6 μg As/l) as the background value. The sum of the calculated and background values can be used as a biological indicator of iAs exposure. Conclusion: We propose 14.8 and 20.1 μg As/l of urinary iAs+MMA as the biological indicators of 3 and 10 μg As/m3 iAs exposure, respectively. PMID:27010090

  13. Acid rain

    SciTech Connect

    White, J.C. )

    1988-01-01

    This book presents the proceedings of the third annual conference sponsored by the Acid Rain Information Clearinghouse (ARIC). Topics covered include: Legal aspects of the source-receptor relationship: an energy perspective; Scientific uncertainty, agency inaction, and the courts; and Acid rain: the emerging legal framework.

  14. Acid rain

    SciTech Connect

    Elsworth, S.

    1985-01-01

    This book was written in a concise and readable style for the lay public. It's purpose was to make the public aware of the damage caused by acid rain and to mobilize public opinion to favor the elimination of the causes of acid rain.

  15. 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.

  16. Asparagusic acid.

    PubMed

    Mitchell, Stephen C; Waring, Rosemary H

    2014-01-01

    Asparagusic acid (1,2-dithiolane-4-carboxylic acid) is a simple sulphur-containing 5-membered heterocyclic compound that appears unique to asparagus, though other dithiolane derivatives have been identified in non-food species. This molecule, apparently innocuous toxicologically to man, is the most probable culprit responsible for the curious excretion of odorous urine following asparagus ingestion. The presence of the two adjacent sulphur atoms leads to an enhanced chemical reactivity, endowing it with biological properties including the ability to substitute potentially for α-lipoic acid in α-keto-acid oxidation systems. This brief review collects the scattered data available in the literature concerning asparagusic acid and highlights its properties, intermediary metabolism and exploratory applications.

  17. Scientific Component Technology Initiative

    SciTech Connect

    Kohn, S; Bosl, B; Dahlgren, T; Kumfert, G; Smith, S

    2003-02-07

    The laboratory has invested a significant amount of resources towards the development of high-performance scientific simulation software, including numerical libraries, visualization, steering, software frameworks, and physics packages. Unfortunately, because this software was not designed for interoperability and re-use, it is often difficult to share these sophisticated software packages among applications due to differences in implementation language, programming style, or calling interfaces. This LDRD Strategic Initiative investigated and developed software component technology for high-performance parallel scientific computing to address problems of complexity, re-use, and interoperability for laboratory software. Component technology is an extension of scripting and object-oriented software development techniques that specifically focuses on the needs of software interoperability. Component approaches based on CORBA, COM, and Java technologies are widely used in industry; however, they do not support massively parallel applications in science and engineering. Our research focused on the unique requirements of scientific computing on ASCI-class machines, such as fast in-process connections among components, language interoperability for scientific languages, and data distribution support for massively parallel SPMD components.

  18. TFTR initial operations

    SciTech Connect

    Young, K.M.; Bell, M.; Blanchard, W.R.; Bretz, N.; Cecchi, J.; Coonrod, J.; Davis, S.; Dylla, H.F.; Efthimion, P.C.; Fonck, R.

    1983-11-01

    The Tokamak Fusion Test Reactor (TFTR) has operated since December 1982 with ohmically heated plasmas. Routine operation with feedback control of plasma current, position, and density has been obtained for plasmas with I/sub p/ approx. = 800 kA, a = 68 cm, R = 250 cm, and B/sub t/ = 27 kG. A maximum plasma current of 1 MA was achieved with q approx. = 2.5. Energy confinement times of approx. 150 msec were measured for hydrogen and deuterium plasmas with anti n/sub e/ approx. = 2 x 10/sup 13/ cm/sup -3/, T/sub e/ (0) approx. = 1.5 keV, T/sub i/ (0) approx. = 1.5 keV, and Z/sub eff/ approx. = 3. The preliminary results suggest a size-cubed scaling from PLT and are consistent with Alcator C scaling where tau approx. nR/sup 2/a. Initial measurements of plasma disruption characteristics indicate current decay rates of approx. 800 kA in 8 ms which is within the TFTR design requirement of 3 MA in 3 ms.

  19. ALOS-2 initial results

    NASA Astrophysics Data System (ADS)

    Kankaku, Yukihiro; Suzuki, Shinichi; Shimada, Masanobu

    2015-10-01

    The Advanced Land Observing Satellite-2 (ALOS-2) was launched from Tanegashima Space Center by H-IIA rocket successfully on 24th May 2014. ALOS-2 carries the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) as the state-of-the-art L-band SAR system which succeeds to PALSAR onboard ALOS. PALSAR-2 uses almost whole bandwidth allocated for L-band active sensor of Earth Exploration Satellites Service specified by the Radio Regulation in order to realize the high resolution observation, and also, it transmits more than 6 kW power for lower Noise Equivalent Sigma Zero using 180 TRMs driven by Gallium Nitride (GaN) amplifier which is the first use in space. Furthermore, because ALOS-2 carries the SAR system only, PALSAR-2 antenna can be mounted under the satellite body. It enables to observe right-/left-looking observation by satellite maneuvering. And the high accuracy orbit control to maintain the satellite within 500 m radius tube against the reference orbit enables high coherence for the InSAR processing. Using these new technologies, ALOS-2 has been operating to fulfill the mission requirements such as disaster monitoring and so on. This document introduces the initial result of ALOS-2 from the first year operation.

  20. Urban Environment Initiative

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Urban Environment Initiative (UEI), has been established as part of a Cooperative Agreement with the National Aeronautics and Space Administration (NASA). The UEI is part of NASA's overall High Performance Computing and Communications (HPCC) and the Information Infrastructure Technology Applications (IITA) programs. The goal of the UEI is to provide public access to Earth Science information and promote its use with a focus on the environment of urban areas. This goal will be accomplished through collaborative efforts of the UEI team with both community-based and local/regional governmental organizations. The UEI team is comprised of four organizations representing private industry, NASA, and universities: Prime Technologies Service Corporation, NASA's Minority University Space Interdisciplinary Network (MU-SPIN) California State University, at Los Angeles, and Central State University (Wilberforce, OH). "Urban Environment" refers to the web of environmental, economic, and social factors that combine to create the urban world in which we live. Examples of these factors are population distribution, neighborhood demographic profiles, economic resources, business activities, location and concentration of environmental hazards and various pollutants, proximity and level of urban services, which form the basis of the urban environment and ultimately affect our lives and experiences. The use of Geographic Information Systems (GIS) and remote sensing allows data to be visualized in the forms of maps and spatial images. The use of these tools allow analysis of information about urban environments. Also included are descriptions of the four query types which will assist in understanding the maps.

  1. Moon-Mars Initiative

    NASA Astrophysics Data System (ADS)

    2005-06-01

    On 27 May, the AGU Council unanimously adopted a position statement on NASA's strategic plan released in February 2005:: "A New Age of Exploration: NASA's Direction for 2005 and Beyond". This strategy incorporates U.S. President Bush's vision for manned space flight to Moon and Mars as described in "A Renewed Spirit of Discovery: The President's Vision for U.S. Space Exploration" announced in January 2004. The statement was drafted by a panel chaired by Eric Barron of Penn State University. AGU calls for the U.S. Administration, Congress, and NASA to continue their commitment to innovative Earth and space science programs. This commitment has placed the U.S. in an international leadership position. It enables environmental stewardship, promotes economic vitality, engages the next generation of scientists and engineers, protects life and property, and fosters exploration. It is, however, threatened by new financial demands placed on NASA by the return to human space flight using the space shuttle, finishing the space station, and launching the Moon-Mars initiative.

  2. Urban Environment Initiative

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Urban Environment Initiative (UEI), has been established as part of a Cooperative Agreement with the National Aeronautics and Space Administration (NASA). The UEI is part of NASA's overall High Performance Computing and Communications (HPCC) and the Information Infrastructure Technology Applications (IITA) programs. The goal of the UEI is to provide public access to Earth Science information and promote its use with a focus on the environment of urban areas. This goal will be accomplished through collaborative efforts of the UEI team with both community-based and local/regional governmental organizations. The UEI team is comprised of four organizations representing private industry, NASA, and universities: Prime Technologies Service Corporation, NASA's Minority University Space Interdisciplinary Network (MU-SPIN) California State University, at Los Angeles, and Central State University (Wilberforce, OH). "Urban Environment" refers to the web of environmental, economic, and social factors that combine to create the urban world in which we live. Examples of these factors are population distribution, neighborhood demographic profiles, economic resources, business activities, location and concentration of environmental hazards and various pollutants, proximity and level of urban services, which form the basis of the urban environment and ultimately affect our lives and experiences. The use of Geographic Information Systems (GIS) and remote sensing allows data to be visualized in the forms of maps and spatial images. The use of these tools allow analysis of information about urban environments. Also included are descriptions of the four query types which will assist in understanding the maps.

  3. Initiation of preterm labor.

    PubMed

    Pawelec, Małgorzata; Pałczyński, Bogusław; Krzemieniewska, Joanna; Karmowski, Mikołaj; Koryś, Jerzy; Lątkowski, Krzysztof; Karmowski, Andrzej

    2013-01-01

    Preterm births are still a major problem in obstetrics. It is estimated that preterm births occur in about 12% of all pregnancies. Due to advances in medical technology and better care of fetuses and premature babies, the preterm mortality rate has been falling (as recently as 1995 the survival rate in the US for premature infants born at 34 weeks amounted to only a fraction of the corresponding rate for those born after 37 weeks). In the US in 2005, preterm births cost society approximately $26 billion, and medical care for premature babies cost more than $51 billion. Only the richest countries can afford such costly medical care. That is why it is not only the individual aspects but also the social aspects that are important when studying preterm birth mechanisms and ways of preventing them. The existing research indicates that both spontaneous mature birth and preterm birth begin and proceed in a similar manner. This is confirmed by the similar involvement in both processes of corticotropin-releasing hormone, urocortin, extracellular stress protein HSP70 (amniotic fluid heat shock protein), prostaglandins, proinflammatory cytokines or glucocorticosteroids. Apparently, at the beginning of either a preterm birth or a term birth, there is a stimulus that ends the development of the fetus or initiates birth. This stimulus works via feedback through placental hormones and through substances present in the fetal membranes, ultimately leading to functional progesterone withdrawal (FPW), thus leaving the uterus sensitive to contractive factors.

  4. The PBRN Initiative

    PubMed Central

    Curro, F.A.; Vena, D.; Naftolin, F.; Terracio, L.; Thompson, V.P.

    2012-01-01

    The NIDCR-supported Practice-based Research Network initiative presents dentistry with an unprecedented opportunity by providing a pathway for modifying and advancing the profession. It encourages practitioner participation in the transfer of science into practice for the improvement of patient care. PBRNs vary in infrastructure and design, and sustaining themselves in the long term may involve clinical trial validation by regulatory agencies. This paper discusses the PBRN concept in general and uses the New York University College of Dentistry’s Practitioners Engaged in Applied Research and Learning (PEARL) Network as a model to improve patient outcomes. The PEARL Network is structured to ensure generalizability of results, data integrity, and to provide an infrastructure in which scientists can address clinical practitioner research interests. PEARL evaluates new technologies, conducts comparative effectiveness research, participates in multidisciplinary clinical studies, helps evaluate alternative models of healthcare, educates and trains future clinical faculty for academic positions, expands continuing education to include “benchmarking” as a form of continuous feedback to practitioners, adds value to dental schools’ educational programs, and collaborates with the oral health care and pharmaceutical industries and medical PBRNs to advance the dental profession and further the integration of dental research and practice into contemporary healthcare (NCT00867997, NCT01268605). PMID:22699662

  5. DNA DAMAGE INDUCED BY METHYLATED TRIVALENT ARSENICALS IS MEDIATED BY REACTIVE OXYGEN SPECIES

    EPA Science Inventory

    Abstract
    Arsenic is a human carcinogen; however, the mechanisms of arsenic's induction of carcinogenic effects have not been identified clearly. We have shown previously that monomethylarsonous acid (MMAIII) and dimethylarsinous acid (DMAIII ) are genotoxic and can damage supe...

  6. Evaluation of urinary speciated arsenic in NHANES: Issues in interpretation in the context of potential inorganic arsenic exposure

    EPA Science Inventory

    Urinary dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) are among the commonly used biomarkers for inorganic arsenic (iAs) exposure, but may also arise from seafood consumption and organoarsenical pesticide applications. We examined speciated urinary arsenic data from...

  7. Evaluation of urinary speciated arsenic in NHANES: Issues in interpretation in the context of potential inorganic arsenic exposure

    EPA Science Inventory

    Urinary dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) are among the commonly used biomarkers for inorganic arsenic (iAs) exposure, but may also arise from seafood consumption and organoarsenical pesticide applications. We examined speciated urinary arsenic data from...

  8. SPECIATION OF ARSENIC COMPOUNDS IN DRINKING WATER BY CAPILLARY ELECTROPHORESIS WITH HYDRODYNAMICALLY MODIFIED ELECTROOSMOTIC FLOW DETECTED THROUGH HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS...

    EPA Science Inventory

    Capillary electrophoresis (CE) was used to speciate four environmentally significant, toxic forms of arsenic: arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid. Hydride generation (HG) was used to convert the species into their respective hydrides. The hydride s...

  9. SPECIATION OF ARSENIC COMPOUNDS IN DRINKING WATER BY CAPILLARY ELECTROPHORESIS WITH HYDRODYNAMICALLY MODIFIED ELECTROOSMOTIC FLOW DETECTED THROUGH HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS..

    EPA Science Inventory

    Capillary electrophoresis (CE) was used to speciate four environmentally significant, toxic forms of arsenic: arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid. Hydride generation (HG) was used to convert the species into their respective hydrides. The hydride ...

  10. SPECIATION OF ARSENIC COMPOUNDS IN DRINKING WATER BY CAPILLARY ELECTROPHORESIS WITH HYDRODYNAMICALLY MODIFIED ELECTROOSMOTIC FLOW DETECTED THROUGH HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS..

    EPA Science Inventory

    Capillary electrophoresis (CE) was used to speciate four environmentally significant, toxic forms of arsenic: arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid. Hydride generation (HG) was used to convert the species into their respective hydrides. The hydride ...

  11. SPECIATION OF ARSENIC COMPOUNDS IN DRINKING WATER BY CAPILLARY ELECTROPHORESIS WITH HYDRODYNAMICALLY MODIFIED ELECTROOSMOTIC FLOW DETECTED THROUGH HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS...

    EPA Science Inventory

    Capillary electrophoresis (CE) was used to speciate four environmentally significant, toxic forms of arsenic: arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid. Hydride generation (HG) was used to convert the species into their respective hydrides. The hydride s...

  12. DNA DAMAGE INDUCED BY METHYLATED TRIVALENT ARSENICALS IS MEDIATED BY REACTIVE OXYGEN SPECIES

    EPA Science Inventory

    Abstract
    Arsenic is a human carcinogen; however, the mechanisms of arsenic's induction of carcinogenic effects have not been identified clearly. We have shown previously that monomethylarsonous acid (MMAIII) and dimethylarsinous acid (DMAIII ) are genotoxic and can damage supe...

  13. Distinct Effects of Sorbic Acid and Acetic Acid on the Electrophysiology and Metabolism of Bacillus subtilis

    PubMed Central

    van Beilen, J. W. A.; Teixeira de Mattos, M. J.; Hellingwerf, K. J.

    2014-01-01

    Sorbic acid and acetic acid are among the weak organic acid preservatives most commonly used to improve the microbiological stability of foods. They have similar pKa values, but sorbic acid is a far more potent preservative. Weak organic acids are most effective at low pH. Under these circumstances, they are assumed to diffuse across the membrane as neutral undissociated acids. We show here that the level of initial intracellular acidification depends on the concentration of undissociated acid and less on the nature of the acid. Recovery of the internal pH depends on the presence of an energy source, but acidification of the cytosol causes a decrease in glucose flux. Furthermore, sorbic acid is a more potent uncoupler of the membrane potential than acetic acid. Together these effects may also slow the rate of ATP synthesis significantly and may thus (partially) explain sorbic acid's effectiveness. PMID:25038097

  14. Distinct effects of sorbic acid and acetic acid on the electrophysiology and metabolism of Bacillus subtilis.

    PubMed

    van Beilen, J W A; Teixeira de Mattos, M J; Hellingwerf, K J; Brul, S

    2014-10-01

    Sorbic acid and acetic acid are among the weak organic acid preservatives most commonly used to improve the microbiological stability of foods. They have similar pKa values, but sorbic acid is a far more potent preservative. Weak organic acids are most effective at low pH. Under these circumstances, they are assumed to diffuse across the membrane as neutral undissociated acids. We show here that the level of initial intracellular acidification depends on the concentration of undissociated acid and less on the nature of the acid. Recovery of the internal pH depends on the presence of an energy source, but acidification of the cytosol causes a decrease in glucose flux. Furthermore, sorbic acid is a more potent uncoupler of the membrane potential than acetic acid. Together these effects may also slow the rate of ATP synthesis significantly and may thus (partially) explain sorbic acid's effectiveness.

  15. Initial Cladding Condition

    SciTech Connect

    E. Siegmann

    2000-08-22

    The purpose of this analysis is to describe the condition of commercial Zircaloy clad fuel as it is received at the Yucca Mountain Project (YMP) site. Most commercial nuclear fuel is encased in Zircaloy cladding. This analysis is developed to describe cladding degradation from the expected failure modes. This includes reactor operation impacts including incipient failures, potential degradation after reactor operation during spent fuel storage in pool and dry storage and impacts due to transportation. Degradation modes include cladding creep, and delayed hydride cracking during dry storage and transportation. Mechanical stresses from fuel handling and transportation vibrations are also included. This Analysis and Model Report (AMR) does not address any potential damage to assemblies that might occur at the YMP surface facilities. Ranges and uncertainties have been defined. This analysis will be the initial boundary condition for the analysis of cladding degradation inside the repository. In accordance with AP-2.13Q, ''Technical Product Development Planning'', a work plan (CRWMS M&O 2000c) was developed, issued, and utilized in the preparation of this document. There are constraints, caveats and limitations to this analysis. This cladding degradation analysis is based on commercial Pressurized Water Reactor (PWR) fuel with Zircaloy cladding but is applicable to Boiling Water Reactor (BWR) fuel. Reactor operating experience for both PWRs and BWRs is used to establish fuel reliability from reactor operation. It is limited to fuel exposed to normal operation and anticipated operational occurrences (i.e. events which are anticipated to occur within a reactor lifetime), and not to fuel that has been exposed to severe accidents. Fuel burnup projections have been limited to the current commercial reactor licensing environment with restrictions on fuel enrichment, oxide coating thickness and rod plenum pressures. The information provided in this analysis will be used in

  16. Incidentalomas: initial management.

    PubMed

    Hitzeman, Nathan; Cotton, Erin

    2014-12-01

    Incidentalomas are increasingly common findings on radiologic studies, causing worry for physicians and patients. Physicians should consider the risk of discovering incidentalomas when contemplating imaging. Patients may assume that incidentalomas are cancer, and may not be aware of the radiation risks associated with repeat imaging. Once incidentalomas are detected, appropriate management is dependent on an informed patient's wishes and the clinical situation. Guidelines are provided for the initial management of eight incidentalomas (pituitary, thyroid, pulmonary, hepatic, pancreatic, adrenal, renal, and ovarian). Patients presenting with pituitary incidentalomas should undergo pituitary-specific magnetic resonance imaging if the lesion is 1 cm or larger, or if it abuts the optic chiasm. Thyroid incidentalomas are ubiquitous, but nodules larger than 1 to 2 cm are of greater concern. Worrisome pulmonary incidentalomas are those larger than 8 mm or those with irregular borders, eccentric calcifications, or low density. However, current guidelines recommend that even pulmonary incidentalomas as small as 4 mm be followed. Solid hepatic incidentalomas 5 mm or larger should be monitored closely, and multiphasic scanning is helpful. Pancreatic cystic neoplasms have malignant potential, and surgery is recommended for pancreatic cysts larger than 3 cm with suspicious features. Adrenal lesions larger than 4 cm are usually biopsied. The Bosniak classification is a well-accepted means of triaging renal incidentalomas. Lesions at category IIF or greater require serial monitoring or surgery. Benign or probably benign ovarian cysts 3 cm or smaller in premenopausal women or 1 cm or smaller in postmenopausal women do not require follow-up. Ovarian cysts with thickened walls or septa, or solid components with blood flow, should be managed closely.

  17. Breckinridge Project, initial effort

    SciTech Connect

    1982-01-01

    This report presents an overview of the Breckinridge Project and summarizes the results achieved during the development phase of the project performed under a Cooperative Agreement with the United States Department of Energy. The Breckinridge Project provides for the design, construction and operation of a 50,000 barrel per day coal liquefaction facility in Breckinridge County, Kentucky. The development of the basic technology used in the Breckinridge Project dates back to the late 1950's and the invention by Hydrocarbon Research, Inc., (HRI) of the ebullated-bed reactor and the H-OIL process. The H-COAL process is based on the H-OIL technology. This coal liquefaction process produces clean low-sulfur petroleum substitutes suitable for most types of hydrocarbon-based fuel and chemical uses regardless of the sulfur content of the coal. A large H-COAL Pilot Plant in operation at Catlettsburg, Kentucky, is converting 220 tons of coal per day into 600 barrels of distillate products by catalytic hydrogenation. The estimated capital cost of the commercial facility is $3.17 billion, and the associated out-of-pocket operating cost is $18 per barrel, both in January 1981 dollars. Financial analysis shows the project to be an attractive investment under certain leveraged conditions which are possible through the assistance of the Synthetic Fuels Corporation. Ashland Synthetic Fuels, Inc. is currently working with the Synthetic Fuels Corporation and potential partners to develop financing for the commercial venture. Critical permits are being obtained and an Environmental Impact Statement is being prepared pursuant to initiating site preparation in early 1983. Commercial operations are expected to start up in early 1988.

  18. Glennan Microsystems Initiative

    NASA Technical Reports Server (NTRS)

    Brillson, Leonard J.

    2002-01-01

    During the 2001-2002 award period, we performed research on Pt/Ti/bare 6H-SiC and bare 4H-SiC interfaces in order to identify their electronic properties as a function of surface preparation. The overall aim of this work is to optimize the electronic properties of metal contacts to SiC as well as the active SiC material itself as a function of surface preparation and subsequent processing. Initially, this work has involved identifying bare surface, subsurface, and metal induced gap states at the metal-SiC contact and correlating energies and densities of deep levels with Schottky barrier heights. We used low energy electron-excited nanoluminescence (LEEN) spectroscopy, X-ray photoemission spectroscopy (XPS), and Secondary Ion Mass Spectrometry (SIMS) in order to correlate electronic states and energy bands with chemical composition, bonding, and crystal structure. A major development has been the discovery of polytype transformations that occur in 4H-SiC under standard microelectronic process conditions used to fabricate SiC devices. Our results are consistent with the stacking fault generation, defect formation, and consequent degradation of SiC recently reported for state-of-the-art ABB commercial diodes under localized electrical stress. Our results highlight the importance of -optimizing process conditions and material properties - anneal times, temperatures and doping to control such structural changes within epitaxial SiC layers. Thus far, we have established threshold times and temperatures beyond which 4H-SiC exhibits 3C-SiC transformation bands for a subset of dopant concentrations and process conditions. On the basis of this temperature time behavior, we have been able to establish an activation energy of approximately 2.5 eV for polytype transformation and dislocation motion. Work continues to establish the fundamental mechanisms underlying the polytype changes and its dependence on material parameters.

  19. Initial Radionuclide Inventories

    SciTech Connect

    H. Miller

    2004-09-19

    The purpose of this analysis is to provide an initial radionuclide inventory (in grams per waste package) and associated uncertainty distributions for use in the Total System Performance Assessment for the License Application (TSPA-LA) in support of the license application for the repository at Yucca Mountain, Nevada. This document is intended for use in postclosure analysis only. Bounding waste stream information and data were collected that capture probable limits. For commercially generated waste, this analysis considers alternative waste stream projections to bound the characteristics of wastes likely to be encountered using arrival scenarios that potentially impact the commercial spent nuclear fuel (CSNF) waste stream. For TSPA-LA, this radionuclide inventory analysis considers U.S. Department of Energy (DOE) high-level radioactive waste (DHLW) glass and two types of spent nuclear fuel (SNF): CSNF and DOE-owned (DSNF). These wastes are placed in two groups of waste packages: the CSNF waste package and the codisposal waste package (CDSP), which are designated to contain DHLW glass and DSNF, or DHLW glass only. The radionuclide inventory for naval SNF is provided separately in the classified ''Naval Nuclear Propulsion Program Technical Support Document'' for the License Application. As noted previously, the radionuclide inventory data presented here is intended only for TSPA-LA postclosure calculations. It is not applicable to preclosure safety calculations. Safe storage, transportation, and ultimate disposal of these wastes require safety analyses to support the design and licensing of repository equipment and facilities. These analyses will require radionuclide inventories to represent the radioactive source term that must be accommodated during handling, storage and disposition of these wastes. This analysis uses the best available information to identify the radionuclide inventory that is expected at the last year of last emplacement, currently identified as

  20. Sustainable Forest Bioenergy Initiative

    SciTech Connect

    Breger, Dwayne; Rizzo, Rob

    2011-09-20

    In the state’s Electricity Restructuring Act of 1998, the Commonwealth of Massachusetts recognized the opportunity and strategic benefits to diversifying its electric generation capacity with renewable energy. Through this legislation, the Commonwealth established one of the nation’s first Renewable Energy Portfolio Standard (RPS) programs, mandating the increasing use of renewable resources in its energy mix. Bioenergy, meeting low emissions and advanced technology standards, was recognized as an eligible renewable energy technology. Stimulated by the state’s RPS program, several project development groups have been looking seriously at building large woody biomass generation units in western Massachusetts to utilize the woody biomass resource. As a direct result of this development, numerous stakeholders have raised concerns and have prompted the state to take a leadership position in pursuing a science based analysis of biomass impacts on forest and carbon emissions, and proceed through a rulemaking process to establish prudent policy to support biomass development which can contribute to the state’s carbon reduction commitments and maintain safeguards for forest sustainability. The Massachusetts Sustainable Forest Bioenergy Initiative (SFBI) was funded by the Department of Energy and started by the Department of Energy Resources before these contentious biomass issues were fully raised in the state, and continued throughout the substantive periods of this policy development. Thereby, while SFBI maintained its focus on the initially proposed Scope of Work, some aspects of this scope were expanded or realigned to meet the needs for groundbreaking research and policy development being advanced by DOER. SFBI provided DOER and the Commonwealth with a foundation of state specific information on biomass technology and the biomass industry and markets, the most comprehensive biomass fuel supply assessment for the region, the economic development impact

  1. Acid fog

    SciTech Connect

    Hileman, B.

    1983-03-01

    Fog in areas of southern California previously thought to be pollution-free has been shown to have a pH as low as 1.69. It has been found to be most acidic after smoggy days, suggesting that it forms on the aerosol associated with the previously exiting smog. Studies on Whiteface Mountain in the Adirondacks show that fog water is often 10 times as acidic as rainwater. As a result of their studies, California plans to spend $4 million on acid deposition research in the coming year. (JMT)

  2. The national geomagnetic initiative

    NASA Astrophysics Data System (ADS)

    The Earth's magnetic field, through its variability over a spectrum of spatial and temporal scales, contains fundamental information on the solid Earth and geospace environment (the latter comprising the atmosphere, ionosphere, and magnetosphere). Integrated studies of the geomagnetic field have the potential to address a wide range of important processes in the deep mantle and core, asthenosphere, lithosphere, oceans, and the solar-terrestrial environment. These studies have direct applications to important societal problems, including resource assessment and exploration, natural hazard mitigation, safe navigation, and the maintenance and survivability of communications and power systems on the ground and in space. Studies of the Earth's magnetic field are supported by a variety of federal and state agencies as well as by private industry. Both basic and applied research is presently supported by several federal agencies, including the National Science Foundation (NSF), U.S. Geological Survey (USGS), U.S. Department of Energy (DOE), National Oceanic and Atmospheric Administration (NOAA), National Aeronautics and Space Administration (NASA), and U.S. Department of Defense (DOD) (through the Navy, Air Force, and Defense Mapping Agency). Although each agency has a unique, well-defined mission in geomagnetic studies, many areas of interest overlap. For example, NASA, the Navy, and USGS collaborate closely in the development of main field reference models. NASA, NSF, and the Air Force collaborate in space physics. These interagency linkages need to be strengthened. Over the past decade, new opportunities for fundamental advances in geomagnetic research have emerged as a result of three factors: well-posed, first-order scientific questions; increased interrelation of research activities dealing with geomagnetic phenomena; and recent developments in technology. These new opportunities can be exploited through a national geomagnetic initiative to define objectives and

  3. The national geomagnetic initiative

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Earth's magnetic field, through its variability over a spectrum of spatial and temporal scales, contains fundamental information on the solid Earth and geospace environment (the latter comprising the atmosphere, ionosphere, and magnetosphere). Integrated studies of the geomagnetic field have the potential to address a wide range of important processes in the deep mantle and core, asthenosphere, lithosphere, oceans, and the solar-terrestrial environment. These studies have direct applications to important societal problems, including resource assessment and exploration, natural hazard mitigation, safe navigation, and the maintenance and survivability of communications and power systems on the ground and in space. Studies of the Earth's magnetic field are supported by a variety of federal and state agencies as well as by private industry. Both basic and applied research is presently supported by several federal agencies, including the National Science Foundation (NSF), U.S. Geological Survey (USGS), U.S. Department of Energy (DOE), National Oceanic and Atmospheric Administration (NOAA), National Aeronautics and Space Administration (NASA), and U.S. Department of Defense (DOD) (through the Navy, Air Force, and Defense Mapping Agency). Although each agency has a unique, well-defined mission in geomagnetic studies, many areas of interest overlap. For example, NASA, the Navy, and USGS collaborate closely in the development of main field reference models. NASA, NSF, and the Air Force collaborate in space physics. These interagency linkages need to be strengthened. Over the past decade, new opportunities for fundamental advances in geomagnetic research have emerged as a result of three factors: well-posed, first-order scientific questions; increased interrelation of research activities dealing with geomagnetic phenomena; and recent developments in technology. These new opportunities can be exploited through a national geomagnetic initiative to define objectives and

  4. 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)

  5. Folic Acid

    MedlinePlus

    ... folic acid can hide signs that you lack vitamin B12, which can cause nerve damage. 10 Do I ... Rosenberg, I.H., et al. (2007). Folate and vitamin B12 status in relation to anemia, macrocytosis and cognitive ...

  6. Tranexamic Acid

    MedlinePlus

    ... is used to treat heavy bleeding during the menstrual cycle (monthly periods) in women. Tranexamic acid is in ... tablets for more than 5 days in a menstrual cycle or take more than 6 tablets in a ...

  7. 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)

  8. Results of the International Validation of the in vivo rodent alkaline comet assay for the detection of genotoxic carcinogens: Individual data for 1,2-dibromoethane, p-anisidine, and o-anthranilic acid in the 2nd step of the 4th phase Validation Study under the JaCVAM initiative.

    PubMed

    Takasawa, Hironao; Takashima, Rie; Narumi, Kazunori; Kawasako, Kazufumi; Hattori, Akiko; Kawabata, Masayoshi; Hamada, Shuichi

    2015-07-01

    As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative International Validation Study of an in vivo rat alkaline comet assay, we examined 1,2-dibromoethane (DBE), p-anisidine (ASD), and o-anthranilic acid (ANT) to investigate the effectiveness of the comet assay in detecting genotoxic carcinogens. Each of the three test chemicals was administered to 5 male Sprague-Dawley rats per group by oral gavage at 48, 24, and 3h before specimen preparation. Single cells were collected from the liver and glandular stomach at 3h after the final dosing, and the specimens prepared from these two organs were subjected to electrophoresis under alkaline conditions (pH>13). The percentage of DNA intensity in the comet tail was then assessed using an image analysis system. A micronucleus (MN) assay was also conducted using these three test chemicals with the bone marrow (BM) cells collected from the same animals simultaneously used in the comet assay, i.e., combination study of the comet assay and BM MN assay. A genotoxic (Ames positive) rodent carcinogen, DBE gave a positive result in the comet assay in the present study, while a genotoxic (Ames positive) non-carcinogen, ASD and a non-genotoxic (Ames negative) non-carcinogen, ANT showed negative results in the comet assay. All three chemicals produced negative results in the BM MN assay. While the comet assay findings in the present study were consistent with those obtained from the rodent carcinogenicity studies for the three test chemicals, we consider the positive result in the comet assay for DBE to be particularly meaningful, given that this chemical produced a negative result in the BM MN assay. Therefore, the combination study of the comet assay and BM MN assay is a useful method to detect genotoxic carcinogens that are undetectable with the BM MN assay alone. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. 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.).

  10. The Chlorate-Iodine-Nitrous Acid Clock Reaction

    PubMed Central

    Sant'Anna, Rafaela T. P.; Faria, Roberto B.

    2014-01-01

    A new clock reaction based on chlorate, iodine and nitrous acid is presented. The induction period of this new clock reaction decreases when the initial concentrations of chlorate, nitrous acid and perchloric acid increase, but it is independent on the initial iodine concentration. The proposed mechanism is based on the LLKE autocatalytic mechanism for the chlorite-iodide reaction and the initial reaction between chlorate and nitrous acid to produce nitrate and chlorite. This new clock reaction opens the possibility for a new family of oscillating reactions containing chlorate or nitrous acid, which in both cases has not been observed until now. PMID:25313803

  11. The chlorate-iodine-nitrous acid clock reaction.

    PubMed

    Sant'Anna, Rafaela T P; Faria, Roberto B

    2014-01-01

    A new clock reaction based on chlorate, iodine and nitrous acid is presented. The induction period of this new clock reaction decreases when the initial concentrations of chlorate, nitrous acid and perchloric acid increase, but it is independent on the initial iodine concentration. The proposed mechanism is based on the LLKE autocatalytic mechanism for the chlorite-iodide reaction and the initial reaction between chlorate and nitrous acid to produce nitrate and chlorite. This new clock reaction opens the possibility for a new family of oscillating reactions containing chlorate or nitrous acid, which in both cases has not been observed until now.

  12. Bioeconomy Initiative at MBI International

    SciTech Connect

    Kleff, Susanne, Ph.D.

    2011-11-30

    Di-carboxylic acids have the potential to replace petrochemicals used in the polymer industry (Werpy and Petersen, 2004). MBI developed a process for the production of succinic acid using a proprietary organism. During this work MBI assessed the feasibility to produce other carboxylic acids either using A. succinogenes or other organisms. The development of recombinant A. succinogenes strain derivatives for a mono-carboxylic acid through over-expression of enzymatic activities was successful. Fermentations achieved titers of 58 g/L for this organic acid. Recombinant strains that produced the same acid, but a different stereoisomer, reached titers of 10 g/L. Attempts to increase the titers for this isomer as well as other organic acids were unsuccessful. MBI is looking for commercial partners to pursue the development of recombinant A. succinogenes strains for the production of other organic acids. Attempts to develop recombinant strains of A. succinogenes for fumaric acid production through introduction of various antisense RNA constructs were unsuccessful. Alternative suitable organisms were evaluated and Rhizopus oryzae, a natural fumaric acid producer with potential for process improvements, was selected. A novel fermentation and one-step recovery process was developed that allowed capture of IP, produced titers of >80 g/L with a productivity of 1.8 g/L-h and 57% (g/g glucose) yield. The process was scaled to 2000 L pilot scale. The economic analysis projected a production cost of 72 c/lb. Recycling and re-use of the base was demonstrated and incorporated into the process. The ability of the organism to produce fumaric acid from other carbon sources and biomass hydrolysate was demonstrated. The production of other organic acids was evaluated and techno-economic de-risking roadmap documents were prepared.

  13. Acidification and Acid Rain

    NASA Astrophysics Data System (ADS)

    Norton, S. A.; Veselã½, J.

    2003-12-01

    endangers the existing biota. Concerns about acid (or acidic) rain in its modern sense were publicized by the Swedish soil scientist Svante Odén (1968). He argued, initially in the Swedish press, that long-term increases in the atmospheric deposition of acid could lower the pH of surface waters, cause a decline in fish stocks, deplete soils of nutrients, and accelerate damage to materials. By the 1970s, acidification of surface waters was reported in many countries in Europe as well as in North America. The late twentieth-century rush to understand the impact of acid rain was driven by: (i) reports of damaged or threatened freshwater fisheries and (ii) damaged forests. Perhaps the earliest linkage between acidic surface water and damage to fish was made by Dahl (1921) in southern Norway. There, spring runoff was sufficiently acidic to kill trout. It was not until the 1970s that a strong link was established between depressed pH, mobilization of aluminum from soil, and fish status ( Schofield and Trojnar,1980). The relationship between acidification of soils and forest health started with hypotheses in the 1960s and has slowly developed. Acid rain enhances the availability of some nutrients (e.g., nitrogen), and may either enhance or diminish the availability of others (e.g., calcium, magnesium, potassium, and phosphorus). Damage to anthropogenic structures, human health, and visibility have also raised concerns. The history of these early developments was summarized by Cowling (1982). Since the 1970s, sulfur and nitrogen emissions to the atmosphere have been reduced by 50-85% and 0-30%, respectively, both in North America and Europe. The emission reductions have occurred as a consequence of knowledge gained and economic factors. While recovery of water quality is underway in some areas, problems of acidification persist, and are now complicated by the effects of climate change ( Schindler, 1997).

  14. Enantioenrichment in sublimed amino acid mixtures.

    PubMed

    Viedma, Cristóbal; Ortiz, José E; de Torres, Trinidad; Cintas, Pedro

    2012-04-14

    A real amplification of an initial enantiomeric excess can be detected when two amino acids are sublimed at high temperature, even if one of the components is a racemic compound that does not convert into a conglomerate by sublimation.

  15. Florida Hydrogen Initiative

    SciTech Connect

    Block, David L

    2013-06-30

    The Florida Hydrogen Initiative (FHI) was a research, development and demonstration hydrogen and fuel cell program. The FHI program objectives were to develop Florida?s hydrogen and fuel cell infrastructure and to assist DOE in its hydrogen and fuel cell activities The FHI program funded 12 RD&D projects as follows: Hydrogen Refueling Infrastructure and Rental Car Strategies -- L. Lines, Rollins College This project analyzes strategies for Florida's early stage adaptation of hydrogen-powered public transportation. In particular, the report investigates urban and statewide network of refueling stations and the feasibility of establishing a hydrogen rental-car fleet based in Orlando. Methanol Fuel Cell Vehicle Charging Station at Florida Atlantic University ? M. Fuchs, EnerFuel, Inc. The project objectives were to design, and demonstrate a 10 kWnet proton exchange membrane fuel cell stationary power plant operating on methanol, to achieve an electrical energy efficiency of 32% and to demonstrate transient response time of less than 3 milliseconds. Assessment of Public Understanding of the Hydrogen Economy Through Science Center Exhibits, J. Newman, Orlando Science Center The project objective was to design and build an interactive Science Center exhibit called: ?H2Now: the Great Hydrogen Xchange?. On-site Reformation of Diesel Fuel for Hydrogen Fueling Station Applications ? A. Raissi, Florida Solar Energy Center This project developed an on-demand forecourt hydrogen production technology by catalytically converting high-sulfur hydrocarbon fuels to an essentially sulfur-free gas. The removal of sulfur from reformate is critical since most catalysts used for the steam reformation have limited sulfur tolerance. Chemochromic Hydrogen Leak Detectors for Safety Monitoring ? N. Mohajeri and N. Muradov, Florida Solar Energy Center This project developed and demonstrated a cost-effective and highly selective chemochromic (visual) hydrogen leak detector for safety monitoring

  16. Nitrated fatty acids: Synthesis and measurement

    PubMed Central

    Woodcock, Steven R.; Bonacci, Gustavo; Gelhaus, Stacy L.; Schopfer, Francisco J.

    2012-01-01

    Nitrated fatty acids are the product of nitrogen dioxide reaction with unsaturated fatty acids. The discovery of peroxynitrite and peroxidase-induced nitration of biomolecules led to the initial reports of endogenous nitrated fatty acids. These species increase during ischemia reperfusion, but concentrations are often at or near the limits of detection. Here, we describe multiple methods for nitrated fatty acid synthesis, sample extraction from complex biological matrices, and a rigorous method of qualitative and quantitative detection of nitrated fatty acids by LC-MS. In addition, optimized instrument conditions and caveats regarding data interpretation are discussed. PMID:23200809

  17. Nitrated fatty acids: synthesis and measurement.

    PubMed

    Woodcock, Steven R; Bonacci, Gustavo; Gelhaus, Stacy L; Schopfer, Francisco J

    2013-06-01

    Nitrated fatty acids are the product of nitrogen dioxide reaction with unsaturated fatty acids. The discovery of peroxynitrite and peroxidase-induced nitration of biomolecules led to the initial reports of endogenous nitrated fatty acids. These species increase during ischemia/reperfusion, but concentrations are often at or near the limits of detection. Here, we describe multiple methods for nitrated fatty acid synthesis and sample extraction from complex biological matrices and a rigorous method of qualitative and quantitative detection of nitrated fatty acids by liquid chromatography-mass spectrometry. In addition, optimized instrument conditions and caveats regarding data interpretation are discussed.

  18. Brain amino acid sensing.

    PubMed

    Tsurugizawa, T; Uneyama, H; Torii, K

    2014-09-01

    The 20 different amino acids, in blood as well as in the brain, are strictly maintained at the same levels throughout the day, regardless of food intake. Gastric vagal afferents only respond to free glutamate and sugars, providing recognition of food intake and initiating digestion. Metabolic control of amino acid homeostasis and diet-induced thermogenesis is triggered by this glutamate signalling in the stomach through the gut-brain axis. Rats chronically fed high-sugar and high-fat diets do not develop obesity when a 1% (w/v) monosodium glutamate (MSG) solution is available in a choice paradigm. Deficiency of the essential amino acid lysine (Lys) induced a plasticity in rats in response to Lys. This result shows how the body is able to identify deficient nutrients to maintain homeostasis. This plastic effect is induced by activin A activity in the brain, particularly in certain neurons in the lateral hypothalamic area (LHA) which is the centre for amino acid homeostasis and appetite. These neurons respond to glutamate signalling in the oral cavity by which umami taste is perceived. They play a quantitative role in regulating ingestion of deficient nutrients, thereby leading to a healthier life. After recovery from malnutrition, rats prefer MSG solutions, which serve as biomarkers for protein nutrition. © 2014 John Wiley & Sons Ltd.

  19. Shock initiation of porous TATB

    SciTech Connect

    Anderson, A.B.; Ginsberg, M.J.; Seitz, W.L.; Wackerle, J.

    1981-01-01

    The planar shock initiation of 1.8-g/cm/sup 3/ TATB has been studied with embedded-Manganin pressure gauges and with the explosive wedge technique. A Lagrangian analysis and an assumed equation of state were used to determine reaction histories during the initiation process. Correlation of reaction rates to state variables has resulted in a shock-strength modified Arrhenius rate law. Numerical simulations employing the rate law have been performed for a number of initiation experiments on TATB.

  20. Acid Rain

    USGS Publications Warehouse

    Bricker, Owen P.; Rice, Karen C.

    1993-01-01

    Acid deposition, or acid rain as it is more commonly referred to, has become a widely publicized environmental issue in the U.S. over the past decade. The term usually conjures up images of fish kills, dying forests, "dead" lakes, and damage to monuments and other historic artifacts. The primary cause of acid deposition is emission of S02 and NOx to the atmosphere during the combustion of fossil fuels. Oxidation of these compounds in the atmosphere forms strong acids - H2SO4 and HNO3 - which are returned to the Earth in rain, snow, fog, cloud water, and as dry deposition.Although acid deposition has only recently been recognized as an environmental problem in the U.S., it is not a new phenomenon (Cogbill & Likens 1974). As early as the middle of the 17th century in England, the deleterious effects of industrial emissions on plants, animals, and humans, and the atmospheric transport of pollutants between England and France had become issues of concern (Evelyn 1661, Graunt 1662). It is interesting that well over three hundred years ago in England, recommendations were made to move industry outside of towns and build higher chimneys to spread the pollution into "distant parts." Increasing the height of smokestacks has helped alleviate local problems, but has exacerbated others. In the U.S. the height of the tallest smokestack has more than doubled, and the average height of smokestacks has tripled since the 1950s (Patrick et al 1981). This trend occurred in most industrialized nations during the 20th century and has had the effect of transforming acid rain from a local urban problem into a problem of global scale.

  1. Acid Rain

    USGS Publications Warehouse

    Bricker, Owen P.; Rice, Karen C.; Dietrich, W.E.; Sposito, Garrison

    1997-01-01

    Acid deposition, or acid rain as it is more commonly referred to, has become a widely publicized environmental issue in the U.S. over the past decade. The term usually conjures up images of fish kills, dying forests, "dead" lakes, and damage to monuments and other historic artifacts. The primary cause of acid deposition is emission of S02 and NOx to the atmosphere during the combustion of fossil fuels. Oxidation of these compounds in the atmosphere forms strong acids - H2SO4 and HNO3 - which are returned to the Earth in rain, snow, fog, cloud water, and as dry deposition.Although acid deposition has only recently been recognized as an environmental problem in the U.S., it is not a new phenomenon (Cogbill & Likens 1974). As early as the middle of the 17th century in England, the deleterious effects of industrial emissions on plants, animals, and humans, and the atmospheric transport of pollutants between England and France had become issues of concern (Evelyn 1661, Graunt 1662). It is interesting that well over three hundred years ago in England, recommendations were made to move industry outside of towns and build higher chimneys to spread the pollution into "distant parts." Increasing the height of smokestacks has helped alleviate local problems, but has exacerbated others. In the U.S. the height of the tallest smokestack has more than doubled, and the average height of smokestacks has tripled since the 1950s (Patrick et al 1981). This trend occurred in most industrialized nations during the 20th century and has had the effect of transforming acid rain from a local urban problem into a problem of global scale.

  2. Initiation into Adolescent Marijuana Use.

    ERIC Educational Resources Information Center

    Brook, Judith S.; And Others

    1980-01-01

    This longitudinal study examined the relationship of three domains (personality/attitudinal orientations, peer relationships, and family socialization factors) with initiation into adolescent marihuana use. (Author/DB)

  3. Initiation into Adolescent Marijuana Use.

    ERIC Educational Resources Information Center

    Brook, Judith S.; And Others

    1980-01-01

    This longitudinal study examined the relationship of three domains (personality/attitudinal orientations, peer relationships, and family socialization factors) with initiation into adolescent marihuana use. (Author/DB)

  4. Home initiation of parenteral nutrition.

    PubMed

    Newton, Alyce F; DeLegge, Mark H

    2007-02-01

    Parenteral nutrition (PN) has been successfully initiated in the home since the early 1990s. The American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) Standards for Specialized Nutrition Support: Home Care Patients, Safe Practices for Parenteral Nutrition, and Guidelines for the Use of Parenteral and Enteral Nutrition in Adult and Pediatric Patients do not contain specific information on the initiation of home PN (HPN). Peer-reviewed, published guidelines are necessary to provide safe and appropriate initiation of HPN. Certain patients should not have PN initiated in the home, such as those with organ failure, uncontrolled diabetes, or uncorrectable electrolyte abnormalities. Excellent candidates for initiation of HPN include patients who have failed enteral feedings, have gastrointestinal (GI) diseases without excessive GI losses, or those with an oncology diagnosis and inability to tube feed. One concern of initiation of HPN is the potential for refeeding syndrome. Refeeding syndrome can be prevented when patients are properly evaluated and managed before initiation of PN. Refeeding syndrome can be avoided by rehydration with fluid and electrolytes before initiation of HPN to normalize blood chemistry when necessary and by starting with a moderate-volume, low-carbohydrate HPN solution compounded with optimal potassium, phosphorus, and magnesium content, and slowly advanced to goal. The "start low and go slow" motto of nutrition support should continue to be followed, but more specific guidelines are needed to assist nutrition support clinicians with safe and appropriate initiation of HPN.

  5. Mechanism of the Initiation of the Cationic Polymerization of Styrenes by Silanes and Activated Covalent Esters

    DTIC Science & Technology

    1989-03-23

    the triflic acid formed by the hvdrolysis of trimethyl silyl triflate. Polmer end aroups do not contain silvl groups, polymnerization is stronglyv...Lewis acids but which are not active alone. Styrenes are also polymerized by mixtures of different acetates and acids 10 , 1 1. The resulting polymers...in different solvents and found that initiation occurs via traces of acids formed by hydrolysis of 1. Experimental Styrenes and solvents were purified

  6. Salicylic acids

    PubMed Central

    Hayat, Shamsul; Irfan, Mohd; Wani, Arif; Nasser, Alyemeni; Ahmad, Aqil

    2012-01-01

    Salicylic acid is well known phytohormone, emerging recently as a new paradigm of an array of manifestations of growth regulators. The area unleashed yet encompassed the applied agriculture sector to find the roles to strengthen the crops against plethora of abiotic and biotic stresses. The skipped part of integrated picture, however, was the evolutionary insight of salicylic acid to either allow or discard the microbial invasion depending upon various internal factors of two interactants under the prevailing external conditions. The metabolic status that allows the host invasion either as pathogenesis or symbiosis with possible intermediary stages in close systems has been tried to underpin here. PMID:22301975

  7. Molecular modeling of nucleic acid structure

    PubMed Central

    Galindo-Murillo, Rodrigo; Bergonzo, Christina

    2013-01-01

    This unit is the first in a series of four units covering the analysis of nucleic acid structure by molecular modeling. This unit provides an overview of computer simulation of nucleic acids. Topics include the static structure model, computational graphics and energy models, generation of an initial model, and characterization of the overall three-dimensional structure. PMID:18428873

  8. 40 CFR 96.71 - Initial certification and recertification procedures

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Monitoring and Reporting § 96.71 Initial certification and recertification procedures (a) The owner or operator of a NOX Budget unit that is subject to an Acid Rain...

  9. Acid rain

    SciTech Connect

    Not Available

    1984-06-01

    An overview is presented of acid rain and the problems it causes to the environment worldwide. The acidification of lakes and streams is having a dramatic effect on aquatic life. Aluminum, present in virtually all forest soils, leaches out readily under acid conditions and interferes with the gills of all fish, some more seriously than others. There is evidence of major damage to forests in European countries. In the US, the most severe forest damage appears to be in New England, New York's Adirondacks, and the central Appalachians. This small region is part of a larger area of the Northeast and Canada that appears to have more acid rainfall than the rest of the country. It is downwind from major coal burning states, which produce about one quarter of US SO/sub 2/ emissions and one sixth of nitrogen oxide emissions. Uncertainties exist over the causes of forest damage and more research is needed before advocating expensive programs to reduce rain acidity. The President's current budget seeks an expansion of research funds from the current $30 million per year to $120 million.

  10. Acrylic acid

    Integrated Risk Information System (IRIS)

    Acrylic acid ( CASRN 79 - 10 - 7 ) 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 Noncarcinogenic Eff

  11. Cacodylic acid

    Integrated Risk Information System (IRIS)

    Cacodylic acid ; CASRN 75 - 60 - 5 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 Noncarcinogenic Eff

  12. Trichloroacetic acid

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 09 / 003F www.epa.gov / iris TOXICOLOGICAL REVIEW OF TRICHLOROACETIC ACID ( CAS No . 76 - 03 - 9 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) September 2011 U.S . Environmental Protection Agency Washington , DC ii DISCLAIMER This document has

  13. Benzoic acid

    Integrated Risk Information System (IRIS)

    Benzoic acid ; CASRN 65 - 85 - 0 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 Noncarcinogenic Effec

  14. Formic acid

    Integrated Risk Information System (IRIS)

    Formic acid ; CASRN 64 - 18 - 6 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 Noncarcinogenic Effect

  15. Phosphoric acid

    Integrated Risk Information System (IRIS)

    Phosphoric acid ; CASRN 7664 - 38 - 2 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 Noncarcinogenic

  16. Selenious acid

    Integrated Risk Information System (IRIS)

    Selenious acid ; CASRN 7783 - 00 - 8 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 Noncarcinogenic E

  17. Dichloroacetic acid

    Integrated Risk Information System (IRIS)

    EPA 635 / R - 03 / 007 www.epa.gov / iris TOXICOLOGICAL REVIEW OF DICHLOROACETIC ACID ( CAS No . 79 - 43 - 6 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) August 2003 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been

  18. The Internet 2 Middleware Initiative.

    ERIC Educational Resources Information Center

    Simco, Greg

    2001-01-01

    Discussion of middleware focuses on the Internet 2 Middleware Initiative. Topics include a description of middleware as a layer of software in a distributed system; middleware characteristics, including transparency, portability, reliability, scalability, and interoperability; and the Internet 2 Middleware Initiative which is focused on research…

  19. Washington State's Student Achievement Initiative

    ERIC Educational Resources Information Center

    Pettitt, Maureen; Prince, David

    2010-01-01

    This article describes Washington State's Student Achievement Initiative, an accountability system implemented in 2005-06 that measures students' gains in college readiness, college credits earned, and degree or certificate completion. The goal of the initiative is to increase educational attainment by focusing on the critical momentum points…

  20. Career Technical Education Pathways Initiative

    ERIC Educational Resources Information Center

    California Community Colleges, Chancellor's Office, 2013

    2013-01-01

    California's education system--the largest in the United States--is an essential resource for ensuring strong economic growth in the state. The Career Technical Education Pathways Initiative (referred to as the Initiative in this report), which became law in 2005, brings together community colleges, K-12 school districts, employers, organized…

  1. Antibiotics trapping transcription initiation intermediates

    PubMed Central

    2011-01-01

    Promoter DNA melting, culminating in the loading of the single-stranded DNA template into the RNA polymerase active site, is a key step in transcription initiation. Recently, the first transcription inhibitors found to block distinct steps of promoter melting were characterized. Here, the impact of these studies is discussed with respect to the current models of transcription initiation. PMID:21468230

  2. Maine: Early Head Start Initiatives

    ERIC Educational Resources Information Center

    Center for Law and Social Policy, Inc. (CLASP), 2012

    2012-01-01

    Maine has two initiatives that build on Early Head Start (EHS). The first initiative, Fund for a Healthy Maine, has since 2001 provided tobacco settlement money to existing Head Start and EHS programs to expand the number of children who receive full-day, full-year services. Local programs have the option of using these funds for EHS, depending on…

  3. Two black hole initial data

    SciTech Connect

    Leski, Szymon

    2005-06-15

    The Misner initial data are a standard example of time-symmetric initial data with two apparent horizons. Compact formulae describing such data are presented in the cases of equal or nonequal masses (i.e. isometric or nonisometric horizons). The interaction energy in the 'Schwarzschild + test-particle' limit of the Misner data is analyzed.

  4. Amino acid transporters: roles in amino acid sensing and signalling in animal cells.

    PubMed Central

    Hyde, Russell; Taylor, Peter M; Hundal, Harinder S

    2003-01-01

    Amino acid availability regulates cellular physiology by modulating gene expression and signal transduction pathways. However, although the signalling intermediates between nutrient availability and altered gene expression have become increasingly well documented, how eukaryotic cells sense the presence of either a nutritionally rich or deprived medium is still uncertain. From recent studies it appears that the intracellular amino acid pool size is particularly important in regulating translational effectors, thus, regulated transport of amino acids across the plasma membrane represents a means by which the cellular response to amino acids could be controlled. Furthermore, evidence from studies with transportable amino acid analogues has demonstrated that flux through amino acid transporters may act as an initiator of nutritional signalling. This evidence, coupled with the substrate selectivity and sensitivity to nutrient availability classically associated with amino acid transporters, plus the recent discovery of transporter-associated signalling proteins, demonstrates a potential role for nutrient transporters as initiators of cellular nutrient signalling. Here, we review the evidence supporting the idea that distinct amino acid "receptors" function to detect and transmit certain nutrient stimuli in higher eukaryotes. In particular, we focus on the role that amino acid transporters may play in the sensing of amino acid levels, both directly as initiators of nutrient signalling and indirectly as regulators of external amino acid access to intracellular receptor/signalling mechanisms. PMID:12879880

  5. A Malic Acid Permease in Isolated Vacuoles of a Crassulacean Acid Metabolism Plant 1

    PubMed Central

    Buser-Suter, Christa; Wiemken, Andres; Matile, Philippe

    1982-01-01

    Vacuoles isolated from mesophyll protoplasts of the Crassulacean acid metabolism plant Bryophyllum daigremontianum take up [14C]l-malic acid from the medium. The initial rates of uptake show saturation kinetics (apparent Km about 1 millimolar). In competition experiments, the uptake rates of l-malic acid are greatly reduced in the presence of a surplus of d-malic and tartronic acid. A number of other acids are much less effective and aspartic and isocitric acid have virtually no effect. The uptake rate of malic acid is unchanged in the presence of ATP and the uncouplers dinitrophenol and carbonyl cyanide m-chlorophenyl hydrazone. When the vacuoles are isolated in the absence of bovine serum albumin or when 1 millimolar HgCl2 is added, they are inactive in transport but retain their malic acid pool. The existence of a specific permease which catalyzes an exchange diffusion of malic acid across the vacuolar membrane is postulated. Images PMID:16662228

  6. Azelaic acid.

    PubMed

    Nazzaro-Porro, M

    1987-12-01

    This review is an update on the literature accumulated over the past 10 years following the original observation that azelaic acid, a naturally occurring and nontoxic C9 dicarboxylic acid, possesses significant biologic properties and a potential as a therapeutic agent. These studies have shown that azelaic acid is a reversible inhibitor of tyrosinase and other oxidoreductases in vitro and that it inhibits mitochondrial respiration. It can also inhibit anaerobic glycolysis. Both in vitro and in vivo it has an antimicrobial effect on both aerobic and anaerobic (Propionibacterium acnes) microorganisms. In tissue culture it exerts a dose- and time-dependent cytotoxic effect on malignant melanocytes, associated with mitochondrial damage and inhibition of deoxyribonucleic acid (DNA) synthesis. Tumoral cell lines not containing tyrosinase are equally affected. Normal cells in culture exposed to the same concentrations of the diacid that are toxic for tumoral cells are in general not damaged. Radioactive azelaic acid has been shown to penetrate tumoral cells at a higher level than normal cells of the corresponding line. Topically applied (a 20% cream), it has been shown to be of therapeutic value in skin disorders of different etiologies. Its beneficial effect on various forms of acne (comedogenic, papulopustular, nodulocystic) has been clearly demonstrated. Particularly important is its action on abnormal melanocytes, which has led to the possibility of obtaining good results on melasma and highly durable therapeutic responses on lentigo maligna. It is also capable of causing regression of cutaneous malignant melanoma, but its role in melanoma therapy remains to be investigated.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Heat fluctuations and initial ensembles.

    PubMed

    Kim, Kwangmoo; Kwon, Chulan; Park, Hyunggyu

    2014-09-01

    Time-integrated quantities such as work and heat increase incessantly in time during nonequilibrium processes near steady states. In the long-time limit, the average values of work and heat become asymptotically equivalent to each other, since they only differ by a finite energy change in average. However, the fluctuation theorem (FT) for the heat is found not to hold with the equilibrium initial ensemble, while the FT for the work holds. This reveals an intriguing effect of everlasting initial memory stored in rare events. We revisit the problem of a Brownian particle in a harmonic potential dragged with a constant velocity, which is in contact with a thermal reservoir. The heat and work fluctuations are investigated with initial Boltzmann ensembles at temperatures generally different from the reservoir temperature. We find that, in the infinite-time limit, the FT for the work is fully recovered for arbitrary initial temperatures, while the heat fluctuations significantly deviate from the FT characteristics except for the infinite initial-temperature limit (a uniform initial ensemble). Furthermore, we succeed in calculating finite-time corrections to the heat and work distributions analytically, using the modified saddle point integral method recently developed by us. Interestingly, we find noncommutativity between the infinite-time limit and the infinite-initial-temperature limit for the probability distribution function (PDF) of the heat.

  8. Initiation of parturition in humans.

    PubMed

    Drover, J W; Casper, R F

    1983-02-15

    The mechanism by which parturition is initiated in humans is largely unknown. The placenta and fetal membranes appear to play the major role in the initiation of labour, and the fetus may influence the timing of labour. Clinical observations and experiments with animals have revealed that placental neuropeptides may be able to control steroid metabolism and trigger the onset of labour, while the fetus may be able to interact with such events to initiate parturition at an appropriate time. However, further study is needed to determine the role of placental releasing factors and glycoprotein hormones and their ability to control placental steroid metabolism.

  9. Thin-film optical initiator

    DOEpatents

    Erickson, Kenneth L.

    2001-01-01

    A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

  10. Carbonate acidizing

    SciTech Connect

    Daccord, G.; Touboul, E.; Lenormand, R.

    1989-02-01

    The authors present the first quantitative study and complete model of the wormholing phenomenon, leading to a means of predicting and optimizing carbonate acidizing treatments. Laboratory experiments on a gypsum model system and computer simulations show that for a given geometry, wormholes can be quantified by a unique parameter, their equivalent hydraulic length. The behavior of this quantifying parameter vs. all the system parameters is studied and allows the quantitative prediction of the efficiency of an acidizing treatment. This study highlights the fractal nature of the phenomenon, which is accounted for in the equations, and the strong effect of the sample geometry. Three types of etching can be obtained: compact, wormhole type, or homogeneous. The optimum conditions for achieving the best skin decrease correspond to the creation of wormholes and can then be defined in terms of fluid reactivity and injection rate.

  11. Tissue, Dosimetry, Metabolism and Excretion of Pentavalent and Trivalent Dimethylated Arsenic in Mice after Oral Administration

    EPA Science Inventory

    Dimethylarsinic acid (DMA(V)) is a rat bladder carcinogen and the major urinary metabolite of administered inorganic arsenic in most mammals. This study examined the disposition of pentavalent and trivalent dimethylated arsenic inmice after acute oral administration. Adult fema...

  12. Tissue, Dosimetry, Metabolism and Excretion of Pentavalent and Trivalent Dimethylated Arsenic in Mice after Oral Administration

    EPA Science Inventory

    Dimethylarsinic acid (DMA(V)) is a rat bladder carcinogen and the major urinary metabolite of administered inorganic arsenic in most mammals. This study examined the disposition of pentavalent and trivalent dimethylated arsenic inmice after acute oral administration. Adult fema...

  13. Gluconic acid production by Penicillium puberulum.

    PubMed

    Elnaghy, M A; Megalla, S E

    1975-01-01

    Twenty-five Penicillium species isolated from Egyptian soil were examined for their ability to produce gluconic acid in surface culture. Of the eight species capable of producing gluconic acid, Penicillium puberulum gave the maximum yield (91% gluconic acid from glucose after 7 days of fermentation with 3% CaCO3). Peptone was the best nitrogen source for acid fermentation and glucose was superior to sucrose. Addition of low concentrations of KH2PO4 and MgSO4 - 7 H2O stimulated acid production. An initial pH of 6.1 was most favourable for acid accumulation and addition of CaCO3 was necessary for maximum acid production.

  14. Hydroxycarboxylic acids and salts

    DOEpatents

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  15. Great Lakes Initiative (GLI) Clearinghouse

    EPA Pesticide Factsheets

    The Great Lakes Initiative Toxicity Clearinghouse is a central location for information on criteria, toxicity data, exposure parameters and other supporting documents used in developing water quality standards in the Great Lakes watershed.

  16. Green Power Partnership Program Initiatives

    EPA Pesticide Factsheets

    EPA's Green Power Partnership has a number of initiatives that focus on the collective green power efforts within specific sectors and renewable energy procurement strategies, which provide recognition opportunities for Partners and increase awareness.

  17. Universally conserved translation initiation factors.

    PubMed

    Kyrpides, N C; Woese, C R

    1998-01-06

    The process by which translation is initiated has long been considered similar in Bacteria and Eukarya but accomplished by a different unrelated set of factors in the two cases. This not only implies separate evolutionary histories for the two but also implies that at the universal ancestor stage, a translation initiation mechanism either did not exist or was of a different nature than the extant processes. We demonstrate herein that (i) the "analogous" translation initiation factors IF-1 and eIF-1A are actually related in sequence, (ii) the "eukaryotic" translation factor SUI1 is universal in distribution, and (iii) the eukaryotic/archaeal translation factor eIF-5A is homologous to the bacterial translation factor EF-P. Thus, the rudiments of translation initiation would seem to have been present in the universal ancestor stage. However, significant development and refinement subsequently occurred independently on both the bacterial lineage and on the archaeal/eukaryotic line.

  18. Discovery Performs Terminal Initiation Burn

    NASA Image and Video Library

    The terminal initiation burn, a left Orbital Maneuvering System engine firing that gave Discovery one last big push toward the space station, took place Feb. 26, 2011 at 10:33 a.m. The burn lasted ...

  19. Dynamics of organic and inorganic arsenic in the solution phase of an acidic fen in Germany

    NASA Astrophysics Data System (ADS)

    Huang, J.-H.; Matzner, E.

    2006-04-01

    Wetland soils play a key role for the transformation of heavy metals in forested watersheds, influencing their mobility, and ecotoxicity. Our goal was to investigate the mechanisms of release from solid to solution phase, the mobility, and the transformation of arsenic species in a fen soil. In methanol-water extracts, monomethylarsonic acid, dimethylarsinic acid, trimethylarsine oxide, arsenobetaine, and two unknown organic arsenic species were found with concentrations up to 14 ng As g -1 at the surface horizon. Arsenate is the dominant species at the 0-30 cm depth, whereas arsenite predominated at the 30-70 cm depth. Only up to 2.2% of total arsenic in fen was extractable with methanol-water. In porewaters, depth gradient spatial variation of arsenic species, pH, redox potentials, and the other chemical parameters along the profile was observed in June together with high proportion of organic arsenic species (up to 1.2 μg As L -1, 70% of total arsenic). Tetramethylarsonium ion and an unknown organic arsenic species were additionally detected in porewaters at deeper horizons. In comparison, the arsenic speciation in porewaters in April was homogeneous with depth and no organic arsenic species were found. Thus, the occurrence of microbial methylation of arsenic in fen was demonstrated for the first time. The 10 times elevated total arsenic concentrations in porewaters in June compared to April were accompanied by elevated concentrations of total iron, lower concentrations of sulfate and the presence of ammonium and phosphate. The low proportion of methanol-water extractable total arsenic suggests a generally low mobility of arsenic in fen soils. The release of arsenic from solid to solution phases in fen is dominantly controlled by dissolution of iron oxides, redox transformation, and methylation of arsenic, driven by microbial activity in the growing season. As a result, increased concentrations of total arsenic and potentially toxic arsenic species in fen

  20. Mitochondria are the main target organelle for trivalent monomethylarsonous acid (MMA(III))-induced cytotoxicity.

    PubMed

    Naranmandura, Hua; Xu, Shi; Sawata, Takashi; Hao, Wen Hui; Liu, Huan; Bu, Na; Ogra, Yasumitsu; Lou, Yi Jia; Suzuki, Noriyuki

    2011-07-18

    Excessive generation of reactive oxygen species (ROS) is considered to play an important role in arsenic-induced carcinogenicity in the liver, lungs, and urinary bladder. However, little is known about the mechanism of ROS-based carcinogenicity, including where the ROS are generated, and which arsenic species are the most effective ROS inducers. In order to better understand the mechanism of arsenic toxicity, rat liver RLC-16 cells were exposed to arsenite (iAs(III)) and its intermediate metabolites [i.e., monomethylarsonous acid (MMA(III)) and dimethylarsinous acid (DMA(III))]. MMA(III) (IC(50) = 1 μM) was found to be the most toxic form, followed by DMA(III) (IC(50) = 2 μM) and iAs(III) (IC(50) = 18 μM). Following exposure to MMA(III), ROS were found to be generated primarily in the mitochondria. DMA(III) exposure resulted in ROS generation in other organelles, while no ROS generation was seen following exposures to low levels of iAs(III). This suggests the mechanisms of induction of ROS are different among the three arsenicals. The effects of iAs(III), MMA(III), and DMA(III) on activities of complexes I-IV in the electron transport chain (ETC) of rat liver submitochondrial particles and on the stimulation of ROS production in intact mitochondria were also studied. Activities of complexes II and IV were significantly inhibited by MMA(III), but only the activity of complexes II was inhibited by DMA(III). Incubation with iAs(III) had no inhibitory effects on any of the four complexes. Generation of ROS in intact mitochondria was significantly increased following incubation with MMA(III), while low levels of ROS generation were observed following incubation with DMA(III). ROS was not produced in mitochondria following exposure to iAs(III). The mechanism underlying cell death is different among As(III), MMA(III), and DMA(III), with mitochondria being one of the primary target organelles for MMA(III)-induced cytotoxicity.