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Sample records for nitrite sulfite oxalate

  1. An Evaluation of Alternatives to Nitrites and Sulfites to Inhibit the Growth of Salmonella enterica and Listeria monocytogenes in Meat Products.

    Science.gov (United States)

    Lamas, Alexandre; Miranda, José Manuel; Vázquez, Beatriz; Cepeda, Alberto; Franco, Carlos Manuel

    2016-10-31

    In recent years, the use of nitrites and sulfites as food preservatives has been a cause for concern due to the health problems that these additives can cause in humans. Natural products have been studied as an alternative, but most of them have hardly been applied in the food industry for technological and economic reasons. In this sense, organic salts such as sodium acetate are a good alternative due to their affordability. Thus, this study evaluated the capacity of sodium nitrite, sodium sulfite, a sodium acetate product (TQI C-6000), and chitosan to inhibit two important foodborne pathogens, Salmonella enterica and Listeria monocytogenes . The MIC of each chemical was in vitro evaluated and their antibacterial action was subsequently checked in situ using minced meat as a food model. MIC values of sodium nitrite (10,000 mg/L) and sodium sulfite (50,000 mg/L) for Salmonella enterica were higher than the values allowed by legislation (450 mg/L for sulfites and 150 mg/L for nitrites). Additionally, the sodium acetate product caused the inhibition of Salmonella enterica and Listeria at a relative low quantity. The two foodborne pathogens were inhibited in the food model with 1% of the sodium acetate product. Additionally, there were no significant differences between sodium nitrite, sodium sulfite, and sodium acetate products in the inhibition of Salmonella enterica and Listeria monocytogenes in the food model. Thus, products based on sodium acetate can be an alternative to traditional preservatives in food products.

  2. An Evaluation of Alternatives to Nitrites and Sulfites to Inhibit the Growth of Salmonella enterica and Listeria monocytogenes in Meat Products

    Directory of Open Access Journals (Sweden)

    Alexandre Lamas

    2016-10-01

    Full Text Available In recent years, the use of nitrites and sulfites as food preservatives has been a cause for concern due to the health problems that these additives can cause in humans. Natural products have been studied as an alternative, but most of them have hardly been applied in the food industry for technological and economic reasons. In this sense, organic salts such as sodium acetate are a good alternative due to their affordability. Thus, this study evaluated the capacity of sodium nitrite, sodium sulfite, a sodium acetate product (TQI C-6000, and chitosan to inhibit two important foodborne pathogens, Salmonella enterica and Listeria monocytogenes. The MIC of each chemical was in vitro evaluated and their antibacterial action was subsequently checked in situ using minced meat as a food model. MIC values of sodium nitrite (10,000 mg/L and sodium sulfite (50,000 mg/L for Salmonella enterica were higher than the values allowed by legislation (450 mg/L for sulfites and 150 mg/L for nitrites. Additionally, the sodium acetate product caused the inhibition of Salmonella enterica and Listeria at a relative low quantity. The two foodborne pathogens were inhibited in the food model with 1% of the sodium acetate product. Additionally, there were no significant differences between sodium nitrite, sodium sulfite, and sodium acetate products in the inhibition of Salmonella enterica and Listeria monocytogenes in the food model. Thus, products based on sodium acetate can be an alternative to traditional preservatives in food products.

  3. Influence of the enzyme dissimilatory sulfite reductase on stable isotope fractionation during sulfate reduction

    Science.gov (United States)

    Mangalo, Muna; Einsiedl, Florian; Meckenstock, Rainer U.; Stichler, Willibald

    2008-03-01

    The stable isotopes of sulfate are often used as a tool to assess bacterial sulfate reduction on the macro scale. However, the mechanisms of stable isotope fractionation of sulfur and oxygen at the enzymatic level are not yet fully understood. In batch experiments with water enriched in 18O we investigated the effect of different nitrite concentrations on sulfur isotope fractionation by Desulfovibrio desulfuricans. With increasing nitrite concentrations, we found sulfur isotope enrichment factors ranging from -11.2 ± 1.8‰ to -22.5 ± 3.2‰. Furthermore, the δ18O values in the remaining sulfate increased from approximately 50-120‰ when 18O-enriched water was supplied. Since 18O-exchange with ambient water does not take place in sulfate, but rather in intermediates of the sulfate reduction pathway (e.g. SO32-), we suggest that nitrite affects the steady-state concentration and the extent of reoxidation of the metabolic intermediate sulfite to sulfate during sulfate reduction. Given that nitrite is known to inhibit the production of the enzyme dissimilatory sulfite reductase, our results suggest that the activity of the dissimilatory sulfite reductase regulates the kinetic isotope fractionation of sulfur and oxygen during bacterial sulfate reduction. Our novel results also imply that isotope fractionation during bacterial sulfate reduction strongly depends on the cell internal enzymatic regulation rather than on the physico-chemical features of the individual enzymes.

  4. Decomposition of oxalate precipitates by photochemical reaction

    International Nuclear Information System (INIS)

    Yoo, J.H.; Kim, E.H.

    1998-01-01

    A photo-radiation method was applied to decompose oxalate precipitates so that it can be dissolved into dilute nitric acid. This work has been studied as a part of partitioning of minor actinides. Minor actinides can be recovered from high-level wastes as oxalate precipitates, but they tend to be coprecipitated together with lanthanide oxalates. This requires another partitioning step for mutual separation of actinide and lanthanide groups. In this study, therefore, the photochemical decomposition mechanism of oxalates in the presence of nitric acid was elucidated by experimental work. The decomposition of oxalates was proved to be dominated by the reaction with hydroxyl radical generated from the nitric acid, rather than with nitrite ion also formed from nitrate ion. The decomposition rate of neodymium oxalate, which was chosen as a stand-in compound representing minor actinide and lanthanide oxalates, was found to be 0.003 M/hr at the conditions of 0.5 M HNO 3 and room temperature when a mercury lamp was used as a light source. (author)

  5. Final report on the safety assessment of sodium sulfite, potassium sulfite, ammonium sulfite, sodium bisulfite, ammonium bisulfite, sodium metabisulfite and potassium metabisulfite.

    Science.gov (United States)

    Nair, Bindu; Elmore, Amy R

    2003-01-01

    Sodium Sulfite, Ammonium Sulfite, Sodium Bisulfite, Potassium Bisulfite, Ammonium Bisulfite, Sodium Metabisulfite, and Potassium Metabisulfite are inorganic salts that function as reducing agents in cosmetic formulations. All except Sodium Metabisulfite also function as hair-waving/straightening agents. In addition, Sodium Sulfite, Potassium Sulfite, Sodium Bisulfite, and Sodium Metabisulfite function as antioxidants. Although Ammonium Sulfite is not in current use, the others are widely used in hair care products. Sulfites that enter mammals via ingestion, inhalation, or injection are metabolized by sulfite oxidase to sulfate. In oral-dose animal toxicity studies, hyperplastic changes in the gastric mucosa were the most common findings at high doses. Ammonium Sulfite aerosol had an acute LC(50) of >400 mg/m(3) in guinea pigs. A single exposure to low concentrations of a Sodium Sulfite fine aerosol produced dose-related changes in the lung capacity parameters of guinea pigs. A 3-day exposure of rats to a Sodium Sulfite fine aerosol produced mild pulmonary edema and irritation of the tracheal epithelium. Severe epithelial changes were observed in dogs exposed for 290 days to 1 mg/m(3) of a Sodium Metabisulfite fine aerosol. These fine aerosols contained fine respirable particle sizes that are not found in cosmetic aerosols or pump sprays. None of the cosmetic product types, however, in which these ingredients are used are aerosolized. Sodium Bisulfite (tested at 38%) and Sodium Metabisulfite (undiluted) were not irritants to rabbits following occlusive exposures. Sodium Metabisulfite (tested at 50%) was irritating to guinea pigs following repeated exposure. In rats, Sodium Sulfite heptahydrate at large doses (up to 3.3 g/kg) produced fetal toxicity but not teratogenicity. Sodium Bisulfite, Sodium Metabisulfite, and Potassium Metabisulfite were not teratogenic for mice, rats, hamsters, or rabbits at doses up to 160 mg/kg. Generally, Sodium Sulfite, Sodium

  6. Utilisation of sugarcane trash and other cellulosic wastes for production of oxalic acid

    Energy Technology Data Exchange (ETDEWEB)

    Mane, J D; Modak, H M; Ramaiah, N A; Jadhav, S J

    1988-01-01

    The nitric acid oxidation process was developed for the production of oxalic acid from sugarcane trash, groundnut shells, corn cobs and rice husks. Good yields of oxalic acid from the above raw materials were obtained under optimum conditions, with sugarcane trash as the preferable raw material. The absorption of waste nitrogen oxide gases in aqueous NaOH to get a valuable by-product, sodium nitrite, was also successful.

  7. Utilisation of sulfites by animals; Utilisation des sulfites par l'animal superieur

    Energy Technology Data Exchange (ETDEWEB)

    Fromageot, P; Chapeville, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    It studied the uptake of radioactive sulfates and sulfites in sulfinic cysteine acid, taurine and cystine in animal organism. The experiments are conducted on rabbits. The experimental procedures are described: one experiment is to sterilize intestines of the animal before to inject it radioactive sulfites or sulfates, the rabbit is sacrificed 28 hours after and its organs analysed. The other experiment is to inject radioactive sulfites or sulfates in an eviscerated rabbit and sacrificed it 30 minutes after. Sulfinic cysteine acid is mainly found in liver extracts after 30 minutes and only after injection of radioactive sulfites, whereas cystine is found after 28 hours in a majority of organ extracts. It showed that sulfur used for the synthesis of sulfinic cysteine acid comes from sulfites intake and that sulfinic cysteine acid is a precursor of taurine and cystine. (M.P.)

  8. Isolated sulfite oxidase deficiency.

    Science.gov (United States)

    Rupar, C A; Gillett, J; Gordon, B A; Ramsay, D A; Johnson, J L; Garrett, R M; Rajagopalan, K V; Jung, J H; Bacheyie, G S; Sellers, A R

    1996-12-01

    Isolated sulfite oxidase (SO) deficiency is an autosomal recessively inherited inborn error of sulfur metabolism. In this report of a ninth patient the clinical history, laboratory results, neuropathological findings and a mutation in the sulfite oxidase gene are described. The data from this patient and previously published patients with isolated sulfite oxidase deficiency and molybdenum cofactor deficiency are summarized to characterize this rare disorder. The patient presented neonatally with intractable seizures and did not progress developmentally beyond the neonatal stage. Dislocated lenses were apparent at 2 months. There was increased urine excretion of sulfite and S-sulfocysteine and a decreased concentration of plasma cystine. A lactic acidemia was present for 6 months. Liver sulfite oxidase activity was not detectable but xanthine dehydrogenase activity was normal. The boy died of respiratory failure at 32 months. Neuropathological findings of cortical necrosis and extensive cavitating leukoencephalopathy were reminiscent of those seen in severe perinatal asphyxia suggesting an etiology of energy deficiency. A point mutation that resulted in a truncated protein missing the molybdenum-binding site has been identified.

  9. Utilisation of sulfites by animals

    International Nuclear Information System (INIS)

    Fromageot, P.; Chapeville, F.

    1955-01-01

    It studied the uptake of radioactive sulfates and sulfites in sulfinic cysteine acid, taurine and cystine in animal organism. The experiments are conducted on rabbits. The experimental procedures are described: one experiment is to sterilize intestines of the animal before to inject it radioactive sulfites or sulfates, the rabbit is sacrificed 28 hours after and its organs analysed. The other experiment is to inject radioactive sulfites or sulfates in an eviscerated rabbit and sacrificed it 30 minutes after. Sulfinic cysteine acid is mainly found in liver extracts after 30 minutes and only after injection of radioactive sulfites, whereas cystine is found after 28 hours in a majority of organ extracts. It showed that sulfur used for the synthesis of sulfinic cysteine acid comes from sulfites intake and that sulfinic cysteine acid is a precursor of taurine and cystine. (M.P.)

  10. Inhibition of polyphenoloxidase by sulfite

    International Nuclear Information System (INIS)

    Sayavedra-Soto, L.A.; Montgomery, M.W.

    1986-01-01

    When polyphenoloxidase (PPO) was exposed to sulfite prior to substrate addition, inhibition was irreversible. Trials to regenerate PPO activity, using extensive dialysis, column chromatography, and addition of copper salts were not successful. Increased concentrations of sulfite and pH levels less than 5 enhanced the inhibition of PPO by sulfite. At pH 4, concentrations greater than 0.04 mg/mL completely inhibited 1000 units of PPO activity almost instantaneously. This suggested that the HSO 3 - molecule was the main component in the sulfite system inhibiting PPO. Column chromatography, extensive dialysis, and gel electrophoresis did not demonstrate 35 SO 2 bound to purified pear PPO protein. Formation of extra protein bands of sulfite inhibited purified pear PPO fractions on gel electrophoresis was demonstrated. This and other evidence suggested that the major mode of direct irreversible inhibition of PPO was modification of the protein structure, with retention of its molecular unity

  11. Sulfite oxidase biosensors based on tetrathiafulvalene modified screen-printed carbon electrodes for sulfite determination in wine.

    Science.gov (United States)

    Molinero-Abad, Begoña; Alonso-Lomillo, M Asunción; Domínguez-Renedo, Olga; Arcos-Martínez, M Julia

    2014-02-17

    Screen-printed carbon electrodes have been modified with tetrathiafulvalene and sulfite oxidase enzyme for the sensitive and selective detection of sulfite. Amperometric experimental conditions were optimized taking into account the importance of quantifying sulfite in wine samples and the inherent complexity of these samples, particularly red wine. The biosensor responds to sulfite giving a cathodic current (at +200 mV vs screen-printed Ag/AgCl electrode and pH 6) in a wide concentration range, with a capability of detection of 6 μM (α=β=0.05) at 60°C. The method has been applied to the determination of sulfite in white and red samples, with averages recoveries of 101.5% to 101.8%, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Some effects of sulfite on photosynthesis in lichens

    Energy Technology Data Exchange (ETDEWEB)

    Hill, D J

    1974-01-01

    Details of the effect of sulfite H/sup 14/CO/sub 3//sup -/ fixation in the light were studied. The reduction of fixation by sulfite was rapid, taking place within 30 min of contact with the lichen. Parmelia physodes recovered in 24 h from almost total reduction of fixation caused by I h treatment with 0.4 mM sulfite but Usnea sp. did not. Studies with (/sup -35/S)sulfite indicated that sulfite was taken up nonlinearly with time and that it was bound to protein. Algae isolated from Usnea sp., Parmelia physodes and Lecanora conizaeoides were similar in their response to sulfite, although the intact lichen L. conizaeoides is known to be more resistant L. Conizaeoides did not seem to be resistant to sulfite by causing rapid oxidation of sulfite to sulfate. There was no marked effect of temperature on the concentration of sulfite required to reduce fixation in Usnea sp.

  13. Ion chromatographic determination of sulfites in foods.

    Science.gov (United States)

    Anderson, C; Warner, C R; Daniels, D H; Padgett, K L

    1986-01-01

    Ion chromatography (IC) is shown to be a promising technique for the determination of sulfites (SO2, SO2/3-) in foods. Results of a 10 min flash distillation and 10 min IC determination compare favorably with the results from the conventional Monier-Williams method for total sulfite in a variety of food matrices. The IC technique also provides a wealth of additional information, such as (1) sulfite and sulfate (oxidized sulfite) content of the spiking or treatment solution, (2) residual sulfite applied to the food after oxidation losses in the treatment process, (3) free sulfite in foods, and (4) total sulfite in foods. As a further check on the Monier-Williams method, the sulfate content of the trapping solution can be determined by IC. Because the IC technique traps the liberated SO2 in a non-oxidizing rather than an oxidizing medium, it is considered free from interfering sulfides and organic sulfur-containing groups which can give false positives in the Monier-Williams method. IC thus offers a high speed, more sensitive, and cost-effective alternative to conventional techniques for the determination of sulfite in foods.

  14. Sulfite oxidase activity of cytochrome c: Role of hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Murugesan Velayutham

    2016-03-01

    Full Text Available In humans, sulfite is generated endogenously by the metabolism of sulfur containing amino acids such as methionine and cysteine. Sulfite is also formed from exposure to sulfur dioxide, one of the major environmental pollutants. Sulfite is used as an antioxidant and preservative in dried fruits, vegetables, and beverages such as wine. Sulfite is also used as a stabilizer in many drugs. Sulfite toxicity has been associated with allergic reactions characterized by sulfite sensitivity, asthma, and anaphylactic shock. Sulfite is also toxic to neurons and cardiovascular cells. Recent studies suggest that the cytotoxicity of sulfite is mediated by free radicals; however, molecular mechanisms involved in sulfite toxicity are not fully understood. Cytochrome c (cyt c is known to participate in mitochondrial respiration and has antioxidant and peroxidase activities. Studies were performed to understand the related mechanism of oxidation of sulfite and radical generation by ferric cytochrome c (Fe3+cyt c in the absence and presence of H2O2. Electron paramagnetic resonance (EPR spin trapping studies using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO were performed with sulfite, Fe3+cyt c, and H2O2. An EPR spectrum corresponding to the sulfite radical adducts of DMPO (DMPO-SO3- was obtained. The amount of DMPO-SO3- formed from the oxidation of sulfite by the Fe3+cyt c increased with sulfite concentration. In addition, the amount of DMPO-SO3- formed by the peroxidase activity of Fe3+cyt c also increased with sulfite and H2O2 concentration. From these results, we propose a mechanism in which the Fe3+cyt c and its peroxidase activity oxidizes sulfite to sulfite radical. Our results suggest that Fe3+cyt c could have a novel role in the deleterious effects of sulfite in biological systems due to increased production of sulfite radical. It also shows that the increased production of sulfite radical may be responsible for neurotoxicity and some of the injuries which

  15. Risk analysis of sulfites used as food additives in China.

    Science.gov (United States)

    Zhang, Jian Bo; Zhang, Hong; Wang, Hua Li; Zhang, Ji Yue; Luo, Peng Jie; Zhu, Lei; Wang, Zhu Tian

    2014-02-01

    This study was to analyze the risk of sulfites in food consumed by the Chinese people and assess the health protection capability of maximum-permitted level (MPL) of sulfites in GB 2760-2011. Sulfites as food additives are overused or abused in many food categories. When the MPL in GB 2760-2011 was used as sulfites content in food, the intake of sulfites in most surveyed populations was lower than the acceptable daily intake (ADI). Excess intake of sulfites was found in all the surveyed groups when a high percentile of sulfites in food was in taken. Moreover, children aged 1-6 years are at a high risk to intake excess sulfites. The primary cause for the excess intake of sulfites in Chinese people is the overuse and abuse of sulfites by the food industry. The current MPL of sulfites in GB 2760-2011 protects the health of most populations. Copyright © 2014 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  16. Macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid

    International Nuclear Information System (INIS)

    Lidong, Wang; Yongliang, Ma; Wendi, Zhang; Qiangwei, Li; Yi, Zhao; Zhanchao, Zhang

    2013-01-01

    Graphical abstract: Ascorbic acid is used as an inhibitor to retard the oxidation rate of magnesium sulfite. It shows that the oxidation rate would decrease greatly with the rise of initial ascorbic acid concentration, which provides a useful reference for sulfite recovery in magnesia desulfurization. -- Highlights: • We studied the kinetics of magnesium sulfite oxidation inhibited by ascorbic acid. • The oxidation process was simulated by a three-phase model and proved by HPLC–MS. • We calculated the kinetic parameters of intrinsic oxidation of magnesium sulfite. -- Abstract: Magnesia flue gas desulfurization is a promising process for small to medium scale industrial coal-fired boilers in order to reduce sulfur dioxide emissions, in which oxidation control of magnesium sulfite is of great importance for the recycling of products. Effects of four inhibitors were compared by kinetic experiments indicating that ascorbic acid is the best additive, which retards the oxidation process of magnesium sulfite in trace presence. The macrokinetics of magnesium sulfite oxidation inhibited by ascorbic acid were studied. Effects of the factors, including ascorbic acid concentration, magnesium sulfite concentration, oxygen partial pressure, pH, and temperature, were investigated in a stirred reactor with bubbling. The results show that the reaction rate is −0.55 order in ascorbic acid, 0.77 in oxygen partial pressure, and zero in magnesium sulfite concentration, respectively. The apparent activation energy is 88.0 kJ mol −1 . Integrated with the kinetic model, it is concluded that the oxidation rate of magnesium sulfite inhibited by ascorbic acid is controlled by the intrinsic chemical reaction. The result provides a useful reference for sulfite recovery in magnesia desulfurization

  17. Evaluation of oxalate decarboxylase and oxalate oxidase for industrial applications.

    Science.gov (United States)

    Cassland, Pierre; Sjöde, Anders; Winestrand, Sandra; Jönsson, Leif J; Nilvebrant, Nils-Olof

    2010-05-01

    Increased recirculation of process water has given rise to problems with formation of calcium oxalate incrusts (scaling) in the pulp and paper industry and in forest biorefineries. The potential in using oxalate decarboxylase from Aspergillus niger for oxalic acid removal in industrial bleaching plant filtrates containing oxalic acid was examined and compared with barley oxalate oxidase. Ten different filtrates from chemical pulping were selected for the evaluation. Oxalate decarboxylase degraded oxalic acid faster than oxalate oxidase in eight of the filtrates, while oxalate oxidase performed better in one filtrate. One of the filtrates inhibited both enzymes. The potential inhibitory effect of selected compounds on the enzymatic activity was tested. Oxalate decarboxylase was more sensitive than oxalate oxidase to hydrogen peroxide. Oxalate decarboxylase was not as sensitive to chlorate and chlorite as oxalate oxidase. Up to 4 mM chlorate ions, the highest concentration tested, had no inhibitory effect on oxalate decarboxylase. Analysis of the filtrates suggests that high concentrations of chlorate present in some of the filtrates were responsible for the higher sensitivity of oxalate oxidase in these filtrates. Oxalate decarboxylase was thus a better choice than oxalate oxidase for treatment of filtrates from chlorine dioxide bleaching.

  18. Effect of sulfite treatment on total antioxidant capacity, total oxidant status, lipid hydroperoxide, and total free sulfydryl groups contents in normal and sulfite oxidase-deficient rat plasma.

    Science.gov (United States)

    Herken, Emine Nur; Kocamaz, Erdogan; Erel, Ozcan; Celik, Hakim; Kucukatay, Vural

    2009-08-01

    Sulfites, which are commonly used as preservatives, are continuously formed in the body during the metabolism of sulfur-containing amino acids. Sulfite oxidase (SOX) is an essential enzyme in the pathway of the oxidative degradation of sulfite to sulfate protecting cells from sulfite toxicity. This article investigated the effect of sulfite on total antioxidant capacity (TAC), total oxidant status, lipid hydroperoxide (LOOH), and total free sulfydryl groups (-SH) levels in normal and SOX-deficient male albino rat plasma. For this purpose, rats were divided into four groups: control, sulfite-treated, SOX-deficient, and sulfite-treated SOX-deficient groups. SOX deficiency was established by feeding rats a low molybdenum diet and adding to their drinking water 200 ppm tungsten. Sulfite (70 mg/kg) was administered to the animals via their drinking water. SOX deficiency together with sulfite treatment caused a significant increase in the plasma LOOH and total oxidant status levels. -SH content of rat plasma significantly decreased by both sulfite treatment and SOX deficiency compared to the control. There was also a significant decrease in plasma TAC level by sulfite treatment. In conclusion, sulfite treatment affects the antioxidant/oxidant balance of the plasma cells of the rats toward oxidants in SOX-deficient groups.

  19. The role of extended Fe4S4 cluster ligands in mediating sulfite reductase hemoprotein activity.

    Science.gov (United States)

    Cepeda, Marisa R; McGarry, Lauren; Pennington, Joseph M; Krzystek, J; Elizabeth Stroupe, M

    2018-05-28

    The siroheme-containing subunit from the multimeric hemoflavoprotein NADPH-dependent sulfite reductase (SiR/SiRHP) catalyzes the six electron-reduction of SO 3 2- to S 2- . Siroheme is an iron-containing isobacteriochlorin that is found in sulfite and homologous siroheme-containing nitrite reductases. Siroheme does not work alone but is covalently coupled to a Fe 4 S 4 cluster through one of the cluster's ligands. One long-standing hypothesis predicted from this observation is that the environment of one iron-containing cofactor influences the properties of the other. We tested this hypothesis by identifying three amino acids (F437, M444, and T477) that interact with the Fe 4 S 4 cluster and probing the effect of altering them to alanine on the function and structure of the resulting enzymes by use of activity assays, X-ray crystallographic analysis, and EPR spectroscopy. We showed that F437 and M444 gate access for electron transfer to the siroheme-cluster assembly and the direct hydrogen bond between T477 and one of the cluster sulfides is important for determining the geometry of the siroheme active site. Copyright © 2018. Published by Elsevier B.V.

  20. Sulfite-oxido-reductase is involved in the oxidation of sulfite in Desulfocapsa sulfoexigens during disproportionation of thiosulfate and elemental sulfur.

    Science.gov (United States)

    Frederiksen, Trine-Maria; Finster, Kai

    2003-06-01

    The enzymatic pathways of elemental sulfur and thiosulfate disproportionation were investigated using cell-free extract of Desulfocapsa sulfoexigens. Sulfite was observed to be an intermediate in the metabolism of both compounds. Two distinct pathways for the oxidation of sulfite have been identified. One pathway involves APS reductase and ATP sulfurylase and can be described as the reversion of the initial steps of the dissimilatory sulfate reduction pathway. The second pathway is the direct oxidation of sulfite to sulfate by sulfite oxidoreductase. This enzyme has not been reported from sulfate reducers before. Thiosulfate reductase, which cleaves thiosulfate into sulfite and sulfide, was only present in cell-free extract from thiosulfate disproportionating cultures. We propose that this enzyme catalyzes the first step in thiosulfate disproportionation. The initial step in sulfur disproportionation was not identified. Dissimilatory sulfite reductase was present in sulfur and thiosulfate disproportionating cultures. The metabolic function of this enzyme in relation to elemental sulfur or thiosulfate disproportionation was not identified. The presence of the uncouplers HQNO and CCCP in growing cultures had negative effects on both thiosulfate and sulfur disproportionation. CCCP totally inhibited sulfur disproportionation and reduced thiosulfate disproportionation by 80% compared to an unamended control. HQNO reduced thiosulfate disproportionation by 80% and sulfur disproportionation by 90%.

  1. Oxidation of ammonium sulfite in aqueous solutions using ozone technology

    Science.gov (United States)

    Li, Yue; Shang, Kefeng; Lu, Na; Li, Jie; Wu, Yan

    2013-03-01

    How to deal with unstable ammonium sulfite, the byproduct of flue gas desulfuration by ammonia absorption methods, has been a difficult problem in recent years. Oxidation of ammonium sulfite in aqueous solutions using ozone produced by a surface discharge system was investigated in the paper. The oxidation efficiency of ammonium sulfite by ozone and traditional air aeration were compared, and the factors including ozone concentration, gas flow rate, initial concentration of ammonium sulfite solution and reaction temperature were discussed. The results show that the oxidation efficiency of ammonium sulfite by ozone technology reached nearly 100% under the optimum conditions, which had a significant increase compared with that by air aeration.

  2. Estimation of the oxalate content of foods and daily oxalate intake

    Science.gov (United States)

    Holmes, R. P.; Kennedy, M.

    2000-01-01

    BACKGROUND: The amount of oxalate ingested may be an important risk factor in the development of idiopathic calcium oxalate nephrolithiasis. Reliable food tables listing the oxalate content of foods are currently not available. The aim of this research was to develop an accurate and reliable method to measure the food content of oxalate. METHODS: Capillary electrophoresis (CE) and ion chromatography (IC) were compared as direct techniques for the estimation of the oxalate content of foods. Foods were thoroughly homogenized in acid, heat extracted, and clarified by centrifugation and filtration before dilution in water for analysis. Five individuals consuming self-selected diets maintained food records for three days to determine their mean daily oxalate intakes. RESULTS: Both techniques were capable of adequately measuring the oxalate in foods with a significant oxalate content. With foods of very low oxalate content (choice over IC for estimating the oxalate content of foods with a medium (>10 mg/100 g) to high oxalate content due to a faster analysis time and lower running costs, whereas IC may be better suited for the analysis of foods with a low oxalate content. Accurate estimates of the oxalate content of foods should permit the role of dietary oxalate in urinary oxalate excretion and stone formation to be clarified. Other factors, apart from the amount of oxalate ingested, appear to exert a major influence over the amount of oxalate excreted in the urine.

  3. Role of cellular oxalate in oxalate clearance of patients with calcium oxalate monohydrate stone formation and normal controls.

    Science.gov (United States)

    Oehlschläger, Sven; Fuessel, Susanne; Meye, Axel; Herrmann, Jana; Froehner, Michael; Albrecht, Steffen; Wirth, Manfred P

    2009-03-01

    To examine the cellular, plasma, and urinary oxalate and erythrocyte oxalate flux in patients with calcium oxalate monohydrate (COM) stone formation vs normal controls. Pathologic oxalate clearance in humans is mostly integrated in calcium oxalate stone formation. An underlying cause of deficient oxalate clearance could be defective transmembrane oxalate transport, which, in many tissues, is regulated by an anion exchanger (SLC26). We studied 2 groups: 40 normal controls and 41 patients with COM stone formation. Red blood cells were divided for cellular oxalate measurement and for resuspension in a buffered solution (pH 7.40); 0.1 mmol/L oxalate was added. The supernatant was measured for oxalate immediately and 1 hour after incubation. The plasma and urinary oxalate were analyzed in parallel. The mean cellular oxalate concentrations were significantly greater in the normal controls (5.25 +/- 0.47 micromol/L) than in those with COM stone formation (2.36 +/- 0.28 micromol/L; P stone formation (0.31 +/- 0.02 mmol/L) than in the controls (0.24 +/- 0.02 mmol/L; P r = 0.49-0.63; P r = -0.29-0.41; P r = -0.30; P r = 0.25; P stone formation. Our data implicate the presence of a cellular oxalate buffer to stabilize plasma and urinary oxalate concentrations in normal controls.

  4. Plasma oxalic acid and calcium levels in oxalate poisoning

    Science.gov (United States)

    Zarembski, P. M.; Hodgkinson, A.

    1967-01-01

    Observations are reported on five cases of suicide or attempted suicide by poisoning with oxalic acid or ethylene glycol. Elevated oxalic acid levels were observed in the plasma, stomach contents, and a number of tissues. Raised oxalic acid levels in plasma were associated with reduced total and ultrafilterable calcium levels. It is suggested that the reduction in plasma total calcium level is due mainly to the deposition of calcium oxalate in the soft tissues, but inhibition of the parathyroid glands may be a contributory factor. Microscopic examination of various tissues indicated that oxalic acid is deposited in the tissues in two forms: (1) crystalline calcium oxalate dihydrate in the kidney and (2) a non-crystalline complex of calcium oxalate and lipid in liver and other tissues. PMID:5602563

  5. The effect of ingested sulfite on visual evoked potentials, lipid peroxidation, and antioxidant status of brain in normal and sulfite oxidase-deficient aged rats.

    Science.gov (United States)

    Ozsoy, Ozlem; Aras, Sinem; Ozkan, Ayse; Parlak, Hande; Aslan, Mutay; Yargicoglu, Piraye; Agar, Aysel

    2016-07-01

    Sulfite, commonly used as a preservative in foods, beverages, and pharmaceuticals, is a very reactive and potentially toxic molecule which is detoxified by sulfite oxidase (SOX). Changes induced by aging may be exacerbated by exogenous chemicals like sulfite. The aim of this study was to investigate the effects of ingested sulfite on visual evoked potentials (VEPs) and brain antioxidant statuses by measuring superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities. Brain lipid oxidation status was also determined via thiobarbituric acid reactive substances (TBARS) in normal- and SOX-deficient aged rats. Rats do not mimic the sulfite responses seen in humans because of their relatively high SOX activity level. Therefore this study used SOX-deficient rats since they are more appropriate models for studying sulfite toxicity. Forty male Wistar rats aged 24 months were randomly assigned to four groups: control (C), sulfite (S), SOX-deficient (D) and SOX-deficient + sulfite (DS). SOX deficiency was established by feeding rats with low molybdenum (Mo) diet and adding 200 ppm tungsten (W) to their drinking water. Sulfite in the form of sodium metabisulfite (25 mg kg(-1) day(-1)) was given by gavage. Treatment continued for 6 weeks. At the end of the experimental period, flash VEPs were recorded. Hepatic SOX activity was measured to confirm SOX deficiency. SOX-deficient rats had an approximately 10-fold decrease in hepatic SOX activity compared with the normal rats. The activity of SOX in deficient rats was thus in the range of humans. There was no significant difference between control and treated groups in either latence or amplitude of VEP components. Brain SOD, CAT, and GPx activities and brain TBARS levels were similar in all experimental groups compared with the control group. Our results indicate that exogenous administration of sulfite does not affect VEP components and the antioxidant/oxidant status of aged rat brains. © The Author

  6. Spent sulfite liquor developments

    Energy Technology Data Exchange (ETDEWEB)

    Black, H H

    1958-01-01

    A review of methods of utilizing spent sulfite liquor, including evaporation and burning, fermentation to produce yeast or alcohol, production of vanillin and lignosulfonates, and use as a roadbinder.

  7. Reduction of sulfate to sulfite by the tobacco leaf

    International Nuclear Information System (INIS)

    Fromageot, P.; Perez-Milan, H.

    1959-01-01

    It is shown that whole tobacco leaf reduces [ 35 SI] sulfate to [ 35 SI] sulfite. The amount and the specific radioactivity of the labelled sulfite recovered indicate that daylight plays an essential part in this process, which is a rapid one. Its quantitative analysis is, however, rendered difficult by oxidation of sulfite to sulfate, which is catalysed by the tissues utilised. Reprint of a paper published in Biochimica et Biophysica Acta, vol. 32, 1959, p. 457-464 [fr

  8. LITERATURE REVIEW FOR OXALATE OXIDATION PROCESSES AND PLUTONIUM OXALATE SOLUBILITY

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C.

    2012-02-03

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign. H Canyon plans to commence conversion of plutonium metal to low-fired plutonium oxide in 2012 for eventual use in the Mixed Oxide Fuel (MOX) Facility. The flowsheet includes sequential operations of metal dissolution, ion exchange, elution, oxalate precipitation, filtration, and calcination. All processes beyond dissolution will occur in HB-Line. The filtration step produces an aqueous filtrate that may have as much as 4 M nitric acid and 0.15 M oxalate. The oxalate needs to be removed from the stream to prevent possible downstream precipitation of residual plutonium when the solution is processed in H Canyon. In addition, sending the oxalate to the waste tank farm is undesirable. This report addresses the processing options for destroying the oxalate in existing H Canyon equipment.

  9. Origin of Urinary Oxalate

    Science.gov (United States)

    Holmes, Ross P.; Knight, John; Assimos, Dean G.

    2007-04-01

    Urinary oxalate is mostly derived from the absorption of ingested oxalate and endogenous synthesis. The breakdown of vitamin C may also contribute small amounts to the urinary oxalate pool. The amount of oxalate absorbed is influenced by the oxalate content of the diet, the concentrations of divalent cations in the gut, the presence of oxalate-degrading organisms, transport characteristics of the intestinal epithelium, and other factors associated with the intestinal environment. Knowledge of pathways associated with endogenous oxalate synthesis is limited. Urinary oxalate excretion can be modified using strategies that limit dietary oxalate absorption and the ingestion of oxalogenic substrates such as hydroxyproline.

  10. 21 CFR 130.9 - Sulfites in standardized food.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Sulfites in standardized food. 130.9 Section 130.9 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION FOOD STANDARDS: GENERAL General Provisions § 130.9 Sulfites in standardized food...

  11. Value-Added Products from FGD Sulfite-Rich Scrubber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Vivak Malhotra

    2010-01-31

    According to the American Coal Ash Association, about 29.25 million tons of flue gas desulfurization (FGD) byproducts were produced in the USA in 2003. Out of 29.25 million tons, 17.35 million tons were sulfite-rich scrubber materials. At present, unlike its cousin FGD gypsum, the prospect for effective utilization of sulfite-rich scrubber materials is not bright. In fact, almost 16.9 million tons are leftover every year. In our pursuit to mitigate the liability of sulfite-rich FGD scrubber materials' disposal, we are attempting to develop value-added products that can commercially compete. More specifically, for this Innovative Concept Phase I project, we have the following objectives: to characterize the sulfite-rich scrubber material for toxic metals; to optimize the co-blending and processing of scrubber material and natural byproducts; to formulate and develop structural composites from sulfite-rich scrubber material; and to evaluate the composites' mechanical properties and compare them with current products on the market. After successfully demonstrating the viability of our research, a more comprehensive approach will be proposed to take these value-added materials to fruition.

  12. Neptunium (IV) oxalate solubility

    International Nuclear Information System (INIS)

    Luerkens, D.W.

    1983-07-01

    The equilibrium solubility of neptunium (IV) oxalate in nitric/oxalic acid solutions was determined at 22 0 C, 45 0 C, and 60 0 C. The concentrations of nitric/oxalic acid solutions represented a wide range of free oxalate ion concentration. A mathematical solubility model was developed which is based on the formation of the known complexes of neptunium (IV) oxalate. the solubility model uses a simplified concentration parameter which is proportional to the free oxalate ion concentration. The solubility model can be used to estimate the equilibrium solubility of neptunium (IV) oxalate over a wide range of oxalic and nitric acid concentrations at each temperature

  13. Hygroscopic properties of oxalic acid and atmospherically relevant oxalates

    Science.gov (United States)

    Ma, Qingxin; He, Hong; Liu, Chang

    2013-04-01

    Oxalic acid and oxalates represent an important fraction of atmospheric organic aerosols, however, little knowledge about the hygroscopic behavior of these particles is known. In this study, the hygroscopic behavior of oxalic acid and atmospherically relevant oxalates (H2C2O4, (NH4)2C2O4, CaC2O4, and FeC2O4) were studied by Raman spectrometry and vapor sorption analyzer. Under ambient relative humidity (RH) of 10-90%, oxalic acid and these oxalates hardly deliquesce and exhibit low hygroscopicity, however, transformation between anhydrous and hydrated particles was observed during the humidifying and dehumidifying processes. During the water adsorption process, conversion of anhydrous H2C2O4, (NH4)2C2O4, CaC2O4, and FeC2O4 to their hydrated particles (i.e., H2C2O4·2H2O, (NH4)2C2O4·H2O, CaC2O4·H2O, and FeC2O4·2H2O) occurred at about 20% RH, 55% RH, 10% RH, and 75% RH, respectively. Uptake of water on hydrated Ca-oxalate and Fe-oxalate particles can be described by a multilayer adsorption isotherm. During the dehumidifying process, dehydration of H2C2O4·2H2O and (NH4)2C2O4·H2O occurred at 5% RH while CaC2O4·H2O and FeC2O4·2H2O did not undergo dehydration. These results implied that hydrated particles represent the most stable state of oxalic acid and oxalates in the atmosphere. In addition, the assignments of Raman shift bands in the range of 1610-1650 cm-1 were discussed according to the hygroscopic behavior measurement results.

  14. Literature review for oxalate oxidation processes and plutonium oxalate solubility

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-01

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign.

  15. Sulfite induces release of lipid mediators by alveolar macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Beck-Speier, I.; Dayal, N.; Maier, L. [GSF - National Research Center for Environment and Health, Neuherberg (Germany). Inst. for Inhalation Biology; Denzlinger, C. [Tuebingen Univ. (Germany). Dept. II, Medical Clinic; Haberl, C. [Tuebingen Univ. (Germany). Dept. III, Medical Clinic

    1998-03-01

    Air pollutants are supposed to modulate physiological responses of alveolar macrophages (AM). This study was addressed to the question whether at neutral pH sulfur(IV) species in comparison to sulfur(VI) species cause AM to release proinflammatory mediators and which pathways are involved in their generation. Supernatants obtained from canine AM treated with sulfite (0.1 mM to 2 mM) enhanced the respiratory burst of canine neutrophils, measured by lucigenin-dependent chemiluminescence, whereas supernatants derived from AM treated with sulfate (1 mM) did not. The neutrophil-stimulating activity released by sulfite-treated AM consisted of platelet-activating factor (PAF) and leukotriene B{sub 4} (LTB{sub 4}) as shown by desensitization of the platelet-activating factor (PAF) and leukotriene B{sub 4} (LTB{sub 4}) as shown by desensitization of the corresponding receptors. Inhibitors of phospholipase A{sub 2} substantially suppressed release of neutrophil-stimulating activity by sulfite-treated AM. Inhibition of 5-lipoxygenase in sulfite-treated AM also reduced neutrophil-stimulating activity, while inhibition of cyclooxygenase had no effect. In conclusion, sulfite induces AM to release lipid mediators via phospholipase A{sub 2}- and 5-lipoxygenase-dependent pathways. These mediators activate neutrophils via the receptors for PAF and LTB{sub 4}. (orig.)

  16. Further Studies on Oxalic Acid Biosynthesis in Oxalate-accumulating Plants 1

    Science.gov (United States)

    Nuss, Richard F.; Loewus, Frank A.

    1978-01-01

    l-Ascorbic acid functions as a precursor of oxalic acid in several oxalate-accumulating plants. The present study extends this observation to include Rumex crispus L. (curly dock), Amaranthus retroflexus L. (red root pigweed), Chenopodium album L. (lamb's-quarters), Beta vulgaris L. (sugar beet), Halogeton glomeratus M. Bieb. (halogeton), and Rheum rhabarbarum L. (rhubarb). Several species with low oxalate content are also examined. When l-[1-14C]ascorbic acid is supplied to young seedlings of R. crispus or H. glomeratus, a major portion of the 14C is released over a 24-hour period as 14CO2 and only a small portion is recovered as [14C]oxalate, unlike cuttings from 2- or 4-month-old plants which retain a large part of the 14C as [14C]oxalic acid and release very little 14CO2. Support for an intermediate role of oxalate in the release of 14CO2 from l-[1-14C]ascorbic acid is seen in the rapid release of 14CO2 by R. crispus and H. glomeratus seedlings labeled with [14C]oxalic acid. The common origin of oxalic acid carbon in the C1 and C2 fragment from l-ascorbic acid is demonstrated by comparison of 14C content of oxalic acid in several oxalate-accumulators after cuttings or seedlings are supplied equal amounts of l-[1-14C]- or l-[UL-14C]ascorbic acid. Theoretically, l-[1-14C]ascorbic acid will produce labeled oxalic acid containing three times as much 14C as l-[UL-14C]ascorbic acid when equal amounts of label are provided. Experimentally, a ratio of 2.7 ± 0.5 is obtained in duplicate experiments with six different species. PMID:16660342

  17. Electrolytic destruction of oxalate ions in plutonium oxalate supernatant

    International Nuclear Information System (INIS)

    Michael, K.M.; Talnikar, S.G.; Jambunathan, U.; Kapoor, S.C.; Ramanujam, A.; Venkataraman, N.

    1996-01-01

    A simple and efficient electrolytic method is described for the destruction of the oxalate ions present in plutonium oxalate supernatant. Using platinum electrode and very little KMnO 4 , in situ generation of Mn 3+ ions is achieved which in turn destroys the oxalate. The use of lower current density helps in achieving maximum current efficiency. The end point is easily detectable by the pink colour of permanganate. By reversing the current, this slight excess of permanganate can be destroyed, thus avoiding the use of hydrogen peroxide. By this simple electrolytic method, the corrosive oxalate ion is completely destroyed and the salt content of the waste solution is considerably reduced. (author). 4 refs., 1 fig., 6 tabs

  18. Destruction of oxalate by reaction with hydrogen peroxide. [Hydrazine oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Mailen, J.C.; Tallent, O.K.; Arwood, P.C.

    1981-09-01

    The destruction of oxalate by oxidation to carbon dioxide using hydrogen peroxide was studied as an alternative method for the disposal of oxalate in connection with the possible use of an aqueous hydrazine oxalate solution as a scrubbing agent for solvent cleanup in processes for the recovery of uranium, plutonium, and thorium by solvent extraction. The rate of oxidation of oxalate by hydrogen peroxide in acid solution at the reflux temperature was adequate for process application; reaction half-times at 100/sup 0/C were less than one hour when the hydrogen peroxide concentration was greater than 0.5 M. The reaction was first order with respect to both the oxalate and hydrogen peroxide concentrations and had an activation energy of 58.7 kJ/g-mol. The rate increased with the hydrogen ion concentration as (H/sup +/)/sup 0/ /sup 3/ but was not significantly affected by the presence of 100 ppM of uranium or copper in solution. In the near-neutral hydrazine oxalate solutions, the reaction of either component with hydrogen peroxide was too slow for process application.

  19. Boletus edulis Nitrite Reductase Reduces Nitrite Content of Pickles and Mitigates Intoxication in Nitrite-intoxicated Mice.

    Science.gov (United States)

    Zhang, Weiwei; Tian, Guoting; Feng, Shanshan; Wong, Jack Ho; Zhao, Yongchang; Chen, Xiao; Wang, Hexiang; Ng, Tzi Bun

    2015-10-08

    Pickles are popular in China and exhibits health-promoting effects. However, nitrite produced during fermentation adversely affects health due to formation of methemoglobin and conversion to carcinogenic nitrosamine. Fruiting bodies of the mushroom Boletus edulis were capable of inhibiting nitrite production during pickle fermentation. A 90-kDa nitrite reductase (NiR), demonstrating peptide sequence homology to fungal nitrite reductase, was isolated from B. edulis fruiting bodies. The optimum temperature and pH of the enzyme was 45 °C and 6.8, respectively. B. edulis NiR was capable of prolonging the lifespan of nitrite-intoxicated mice, indicating that it had the action of an antidote. The enzyme could also eliminate nitrite from blood after intragastric administration of sodium nitrite, and after packaging into capsule, this nitrite-eliminating activity could persist for at least 120 minutes thus avoiding immediate gastric degradation. B. edulis NiR represents the first nitrite reductase purified from mushrooms and may facilitate subsequent applications.

  20. Comparative study of sulfite pretreatments for robust enzymatic saccharification of corn cob residue

    Directory of Open Access Journals (Sweden)

    Bu Lingxi

    2012-12-01

    Full Text Available Abstract Background Corn cob residue (CCR is a kind of waste lignocellulosic material with enormous potential for bioethanol production. The moderated sulphite processes were used to enhance the hydrophily of the material by sulfonation and hydrolysis. The composition, FT-IR spectra, and conductometric titrations of the pretreated materials were measured to characterize variations of the CCR in different sulfite pretreated environments. And the objective of this study is to compare the saccharification rate and yield of the samples caused by these variations. Results It was found that the lignin in the CCR (43.2% had reduced to 37.8%, 38.0%, 35.9%, and 35.5% after the sulfite pretreatment in neutral, acidic, alkaline, and ethanol environments, respectively. The sulfite pretreatments enhanced the glucose yield of the CCR. Moreover, the ethanol sulfite sample had the highest glucose yield (81.2%, based on the cellulose in the treated sample among the saccharification samples, which was over 10% higher than that of the raw material (70.6%. More sulfonic groups and weak acid groups were produced during the sulfite pretreatments. Meanwhile, the ethanol sulfite treated sample had the highest sulfonic group (0.103 mmol/g and weak acid groups (1.85 mmol/g in all sulfite treated samples. In FT-IR spectra, the variation of bands at 1168 and 1190 cm-1 confirmed lignin sulfonation during sulfite pretreatment. The disappearance of the band at 1458 cm-1 implied the methoxyl on lignin had been removed during the sulfite pretreatments. Conclusions It can be concluded that the lignin in the CCR can be degraded and sulfonated during the sulfite pretreatments. The pretreatments improve the hydrophility of the samples because of the increase in sulfonic group and weak acid groups, which enhances the glucose yield of the material. The ethanol sulfite pretreatment is the best method for lignin removal and with the highest glucose yield.

  1. Fabrication of a sulfite biosensor by the use of conducting polymer

    International Nuclear Information System (INIS)

    Hosseini, M.; Bahmani, B; Moztarzadeh, F.; Rabiee, M.

    2008-01-01

    In this research, an enzyme modified electrode has been produced during the electro polymerization of aniline through incorporation of Sulfite oxidase into a conducting polymer. Then the bioelectrochemical response of resulted sulfite biosensor was investigated at different experimental conditions. Study of the stability of the resulted sulfite biosensor revealed that formation of a passive film on the aluminum surface causes improved stability of the electro active films formed on the electrode surface. The bioelectrochemical response of the enzyme-modified electrode as a sulfite biosensor was investigated at different experimental conditions. The optimum p H and temperature were 8.5 and 35 d eg C , respectively. The apparent Michaelis-Menten constant and the activation energy of the enzyme catalyzed reaction were calculated

  2. Dependence of nitrite oxidation on nitrite and oxygen in low-oxygen seawater

    Science.gov (United States)

    Sun, Xin; Ji, Qixing; Jayakumar, Amal; Ward, Bess B.

    2017-08-01

    Nitrite oxidation is an essential step in transformations of fixed nitrogen. The physiology of nitrite oxidizing bacteria (NOB) implies that the rates of nitrite oxidation should be controlled by concentration of their substrate, nitrite, and the terminal electron acceptor, oxygen. The sensitivities of nitrite oxidation to oxygen and nitrite concentrations were investigated using 15N tracer incubations in the Eastern Tropical North Pacific. Nitrite stimulated nitrite oxidation under low in situ nitrite conditions, following Michaelis-Menten kinetics, indicating that nitrite was the limiting substrate. The nitrite half-saturation constant (Ks = 0.254 ± 0.161 μM) was 1-3 orders of magnitude lower than in cultivated NOB, indicating higher affinity of marine NOB for nitrite. The highest rates of nitrite oxidation were measured in the oxygen depleted zone (ODZ), and were partially inhibited by additions of oxygen. This oxygen sensitivity suggests that ODZ specialist NOB, adapted to low-oxygen conditions, are responsible for apparently anaerobic nitrite oxidation.

  3. Recovery of plutonium from oxalate bearing solutions using a mixture of CMPO and TBP

    International Nuclear Information System (INIS)

    Mathur, J.N.; Murali, M.S.; Rizvi, G.H.; Iyer, R.H.; Badheka, L.P.; Banerji, A.; Michael, K.M.; Kapoor, S.C.; Dhumwad, R.K.

    1993-01-01

    A simple and efficient procedure has been developed to quantitatively recover Pu from oxalate bearing solutions using a mixture of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and TBP in dodecane. Pu(IV) in the range of 6.9 to 34.6 mg/1 was quantitatively extracted into 0.2 M CMPO+ 1.2 M TBP in dodecane from an aqueous solution containing 3.0 M HNO 3 and 0.1 M H 2 C 2 O 4 . At such low concentrations of Pu, the distribution ratio (D) did not change but the increase in oxalic acid concentration drastically reduced these values. The variation in HNO 3 concentration at a fixed concentration of 0.2 M CMPO + 1.2 M TBP has shown a dramatic increase in the D values, being 0.3 at 1.0 M and > 10 4 at 7.5 M. The extraction was almost quantitative even at the aqueous to organic ratio of 10:1. Plutonium could be quantitatively recovered (i) by stripping with 0.5 M acetic acid and (ii) by coprecipitating it directly from the organic phase with 0.3 M oxalic acid + 0.3 M calcium nitrate + sodium nitrite. ∼ 92% of the Pu was found in the precipitate and ∼7% in the supernatant. Using this procedure Pu, in a concentrated form (∼50 times), could be recovered from the oxalate bearing solutions without recourse to the destruction of oxalate ion. The slope of 2 from the nitrate ion as well as CMPO variation experiments suggest the species in the organic phase to be PuC 2 O 4 (NO 3 ) 2 .2CMPO. The absorption spectral study of Pu(IV) confirmed the above species in the organic phase. (author). 19 refs., 5 figs., 9 tabs

  4. On the americium oxalate solubility

    International Nuclear Information System (INIS)

    Zakolupin, S.A.; Korablin, Eh.V.

    1977-01-01

    The americium oxalate solubility at different nitric (0.0-1 M) and oxalic (0.0-0.4 M) acid concentrations was investigated in the temperature range from 14 to 60 deg C. The dependence of americium oxalate solubility on the oxalic acid concentration was determined. Increasing oxalic acid concentration was found to reduce the americium oxalate solubility. The dependence of americium oxalate solubility on the oxalic acid concentration was noted to be a minimum at low acidity (0.1-0.3 M nitric acid). This is most likely due to Am(C 2 O 4 ) + , Am(C 2 O 4 ) 2 - and Am(C 2 O 4 ) 3 3- complex ion formation which have different unstability constants. On the basis of the data obtained, a preliminary estimate was carried out for the product of americium oxalate solubility in nitric acid medium (10 -29 -10 -31 ) and of the one in water (6.4x10 -20 )

  5. Value-Added Products From FGD Sulfite-Rich Scrubber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Vivak M. Malhotra

    2006-09-30

    Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber materials are produced every year in the USA. In fact, at present, the production of wet sulfite-rich scrubber cake outstrips the production of wet sulfate-rich scrubber cake by about 6 million tons per year. However, most of the utilization focus has centered on FGD gypsum. Therefore, we have recently initiated research on developing new strategies for the economical, but environmentally-sound, utilization of sulfite-rich scrubber material. In this exploratory project (Phase I), we attempted to ascertain whether it is feasible to develop reconstituted wood replacement products from sulfite-rich scrubber material. In pursuit of this goal, we characterized two different wet sulfite-rich scrubber materials, obtained from two power plants burning Midwestern coal, for their suitability for the development of value-added products. The overall strategy adopted was to fabricate composites where the largest ingredient was scrubber material with additional crop materials as additives. Our results suggested that it may be feasible to develop composites with flexural strength as high as 40 MPa (5800 psi) without the addition of external polymers. We also attempted to develop load-bearing composites from scrubber material, natural fibers, and phenolic polymer. The polymer-to-solid ratio was limited to {le} 0.4. The formulated composites showed flexural strengths as high as 73 MPa (10,585 psi). We plan to harness the research outcomes from Phase I to develop parameters required to upscale our value-added products in Phase II.

  6. Reaction of hydrazine hydrate with oxalic acid: synthesis and crystal structure of dihydrazinium oxalate

    OpenAIRE

    Selvakumar, Rajendran; Premkumar, Thathan; Manivannan, Vadivelu; Saravanan, Kaliannan; Govindarajan, Subbiah

    2014-01-01

    The reaction of oxalic acid with hydrazine hydrate (in appropriate mole ratio) forms the dihydrazinium oxalate under specific experimental condition. The title compound is a molecular salt containing two discrete hydrazinium cations and an oxalate anion. The oxalate anion is perfectly planar and there is a crystallographic centre of symmetry in the middle of the C-C bond. The C-O bond distances are almost equal indicating the presence of resonance in the oxalate ion. The crystal packing is st...

  7. Effects of waterborne nitrite on hematological parameters and stress indicators in olive flounders, Paralichthys olivaceus, raised in bio-floc and seawater.

    Science.gov (United States)

    Kim, Jun-Hwan; Kim, Jin-Young; Lim, Lok-Ji; Kim, Su Kyoung; Choi, Hye Sung; Hur, Young Baek

    2018-06-11

    Juvenile olive flounders, Paralichthys olivaceus (mean weight 2.69 ± 0.31 g), were raised in bio-floc and seawater for six months, these P. olivaceus (mean weight 280.1 ± 10.5 g, mean length 28.37 ± 2.3 cm) were exposed to different concentrations of waterborne nitrite (0, 25, 50, 100, and 200 mg NO 2 - /L) for 7 days. None of the P. olivaceus individuals exposed to bio-floc and seawater containing waterborne nitrite concentrations of 200 mg/L for 7 days survived. Hematological parameters (hemoglobin and hematocrit) were significantly reduced by nitrite exposure. Regarding plasma components, the concentrations of glucose, glutamic oxalate transaminase (GOT), and glutamic pyruvate transaminase (GPT) increased significantly in response to nitrite exposure, whereas cholesterol concentrations significantly decreased. Stress indicators, including concentrations of plasma glucose, cortisol, and liver and gill concentrations of heat shock protein 70 (HSP70) were significantly increased by nitrite exposure. The results of the study indicate that nitrite exposure affected the hematological parameters and stress indicators of P. olivaceus raised in bio-floc and seawater, and these changes were more prominent in the P. olivaceus raised in seawater than those raised in bio-floc. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Copper(I) in fogwater: Determination and interactions with sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Hanbin Xue; Reutlinger, M.; Sigg, L.; Stumm, W. (Swiss Federal Inst. of Tech., Duebendorf (Switzerland)); Lurdes S. Goncalves, M. de (Inst. Superior Tecnico, Lisbon (Portugal))

    1991-10-01

    The copper(I)/(II) redox system was examined in fogwater with respect to the occurrence of Cu(I), the role of sulfite as a reductant of Cu(II) and as a complexing ligand, and the speciation of Cu(I) and Cu(II). Copper(I) was measured in fogwater by the bathocuproine method, which was evaluated for the conditions typically encountered in atmospheric water droplets. Concentrations of Cu(I) in the range 0.1-1 {mu}M were found, which represented between 4 and > 90% of the total copper in these samples. In experiments using concentration ranges of copper and S(IV) close to that of fogwater, the reduction of copper(II) to copper(I) by sulfite was shown to be pH-dependent and to occur rapidly at pH > 6. Calculations of the equilibrium complexation of Cu(I) and Cu(II) under fogwater conditions show that complexes of Cu(I) with sulfite predominate, while for Cu(II) oxalato complexes are important. Sulfite plays an important role as a ligand for Cu(I) in fogwater; Cu(I) may be produced by various reduction reactions, e.g., by organic compounds, and appears to be oxidized only slowly in the presence of S(IV).

  9. Inhibition of tyrosinase-mediated enzymatic browning by sulfite and natural alternatives

    NARCIS (Netherlands)

    Kuijpers, T.F.M.; Vincken, J.P.

    2013-01-01

    Although sulfite is widely used to counteract enzymatic browning, its mechanism has remained largely unknown. We describe a double inhibitory mechanism of sulfite on enzymatic browning, affecting both the enzymatic oxidation of phenols into o‑quinones, as well as the non‑enzymatic

  10. Thorium oxalate solubility and morphology

    International Nuclear Information System (INIS)

    Monson, P.R. Jr.; Hall, R.

    1981-10-01

    Thorium was used as a stand-in for studying the solubility and precipitation of neptunium and plutonium oxalates. Thorium oxalate solubility was determined over a range of 0.001 to 10.0 in the concentration parameter [H 2 C 2 O 4 ]/[HNO 3 ] 2 . Morphology of thorium oxide made from the oxalate precipitates was characterized by scanning electron microscopy. The different morphologies found for oxalate-lean and oxalate-rich precipitations were in agreement with predictions based on precipitation theory

  11. Utilization of spent sulfite liquor carbohydrates

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, A J; Whitmore, L M; Boggs, Jr, L A

    1959-01-01

    Possible utilization of the sugars in spent sulfite liquor in the manufacture of ethanol, torula food yeast, and other fermentation products, and in the production of sugar derivatives, such as the diacetone derivatives, is discussed.

  12. Dissolution of oxalate precipitate and destruction of oxalate ion by hydrogen peroxide in nitric acid solution

    International Nuclear Information System (INIS)

    Kim, Eung-Ho; Chung, Dong-Yong; Park, Jin-Ho; Yoo, Jae-Hyung

    2000-01-01

    This study aims at developing an oxalate precipitation process, which is applicable to a partitioning of long-lived radionuclides from the high-level radioactive liquid waste. In order to achieve this, a study for decomposition-reaction of oxalic acid by hydrogen peroxide was first carried out. The decomposition rates of H 2 O 2 and oxalic acid increased with an increase of nitric acid concentration, and especially those decomposition rates steeply increased at more than 2 M HNO 3 . Based on this result, the decomposition kinetics of H 2 O 2 and oxalic acid were suggested in this work. Then, the dissolution of oxalate precipitate and the destruction of oxalate ion in the solution were examined. Oxalate precipitates were prepared by adding oxalic acid into a simulated radioactive waste containing 8 metallic elements. The precipitates obtained thereby were dissolved in various nitric acid concentrations and reacted with H 2 O 2 at 90degC. When the oxalates were completely dissolved, most of the oxalates were decomposed by adding H 2 O 2 , but in a slurry state the decomposition yield of the oxalate decreased with an increase of the slurry density in the solution. Such phenomenon was considered to be due to a catalytic decomposition of H 2 O 2 on a solid surface of oxalate and the decomposition mechanism was explained by a charge transfer from a surface of oxalate solid to H 2 O 2 , producing OH radicals which can destruct H 2 O 2 explosively. Accordingly, the experimental condition for the decomposition of the oxalate precipitates was found to be most favorable at 3 M HNO 3 under the initial concentrations of 0.2 M oxalate and 1 M H 2 O 2 . At 3M HNO 3 , oxalate precipitates could be safely and completely dissolved, and almost decomposed. Additionally, it was observed that the presence of ferric ion in the solution largely affects the decomposition rate of H 2 O 2 . This could be explained by a chain reaction of hydrogen peroxide with ferric ion in the solution

  13. Potentiometric sulfite biosensor based on entrapment of sulfite oxidase in a polypyrrole film on a platinum electrode modified with platinum nanoparticles

    International Nuclear Information System (INIS)

    Adeloju, Samuel B.; Hussain, Shahid

    2016-01-01

    The surface of a platinum electrode has been modified with platinum nanoparticles (PtNPs) and the enzyme sulfite oxidase (SOx), was entrapped on its surface in an ultrathin polypyrrole (PPy) film. The PtNPs, with a diameter of 30-40 nm, were deposited on the Pt electrode by cycling the electrode potential 20 times from -200 to 200 mV at a sweep rate of 50 mV.s"-"1. Morphological evidence of the successful incorporation of SOx and the presence of PtNPs were obtained by scanning electron microscopy. Also, the electrochemical behavior of the PtNPs/PPy-SOx film was examined by cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy and potentiometry. Under optimized conditions, the biosensor achieved a sensitivity of 57.5 mV.decade"-"1, a linear response that extends from 0.75 to 65 μM of sulfite, a detection limit of 12.4 nM, and a response time of 3-5 s. The biosensor was successfully applied to the determination of sulfite in wine and beer samples. (author)

  14. Vibrational studies in aqueous solutions. Part II. The acid oxalate ion and oxalic acid

    Science.gov (United States)

    Shippey, T. A.

    1980-08-01

    Assignments for oxalic acid in solution are re-examined. A detailed assignment of the IR and Raman spectra of the acid oxalate ion is presented for the first time. Raman spectroscopy is used to study the first ionization of oxalic acid.

  15. Uranyl Oxalate Solubility

    Energy Technology Data Exchange (ETDEWEB)

    Leturcq, G.; Costenoble, S.; Grandjean, S. [CEA Marcoule DEN/DRCP/SCPS/LCA - BP17171 - 30207 Bagnols sur Ceze cedex (France)

    2008-07-01

    The solubility of uranyl oxalate was determined at ambient temperature by precipitation in oxalic-nitric solutions, using an initial uranyl concentration of 0.1 mol/L. Oxalic concentration varied from 0.075 to 0.3 mol/L while nitric concentration ranged between 0.75 and 3 mol/L. Dissolution tests, using complementary oxalic-nitric media, were carried out for 550 hours in order to study the kinetic to reach thermodynamic equilibrium. Similar solubility values were reached by dissolution and precipitation. Using the results, it was possible to draw the solubility surface versus oxalic and nitric concentrations and to determine both the apparent solubility constant of UO{sub 2}C{sub 2}O{sub 4}, 3H{sub 2}O (Ks) and the apparent formation constant of the first uranyl-oxalate complex UO{sub 2}C{sub 2}O{sub 4} (log {beta}1), for ionic strengths varying between 1 and 3 mol/L. Ks and log {beta}1 values were found to vary from 1.9 10{sup -8} to 9.2 10{sup -9} and from 5.95 to 6.06, respectively, when ionic strength varied from 1 to 3 mol/L. A second model may fit our data obtained at an ionic strength of 3 mol/L suggesting as reported by Moskvin et al. (1959) that no complexes are formed for [H{sup +}] at 3 M. The Ks value would then be 1.3 10{sup -8}. (authors)

  16. Genetics Home Reference: isolated sulfite oxidase deficiency

    Science.gov (United States)

    ... and Management Resources (1 link) GeneReview: Isolated Sulfite Oxidase Deficiency General Information from MedlinePlus (5 links) Diagnostic Tests Drug Therapy Genetic Counseling Palliative Care Surgery and ...

  17. Effect of Sulfites on Antioxidant Activity, Total Polyphenols, and Flavonoid Measurements in White Wine.

    Science.gov (United States)

    Nardini, Mirella; Garaguso, Ivana

    2018-03-09

    Polyphenols content and antioxidant activity are directly related to the quality of wine. Wine also contains sulfites, which are added during the winemaking process. The present study aimed to evaluate the effects of sulfites on the assays commonly used to measure the antioxidant activity and polyphenols and flavonoids content of white wines. The effects of sulfites were explored both in the standard assays and in white wine. The addition of sulfites (at 1-10 μg) in the standard assays resulted in a significant, positive interference in the Folin-Ciocalteu's assay used for polyphenols measurements and in both the Ferric Reducing Antioxidant Power and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation decolorization assays, which were used for antioxidant activity evaluation. A negative interference of sulfites (at 1-20 μg) was observed for the colorimetric aluminium-chloride flavonoids assay. The addition of sulfites to organic white wines (at 25-200 mg/L wine) clearly resulted in a significant overestimation of antioxidant activity and polyphenols content, and in an underestimation of flavonoids concentration. To overcome sulfite interferences, white wines were treated with cross-linked polyvinylpyrrolidone. The total polyphenols content and antioxidant activity measurements obtained after polyvinylpyrrolidone treatment were significantly lower than those obtained in the untreated wines. Flavonoids were expected to be higher after polyvinylpyrrolidone treatment, but were instead found to be lower than for untreated wines, suggesting that in addition to sulfites, other non-phenolic reducing compounds were present in white wine and interfered with the flavonoid assay. In view of our results, we advise that a purification procedure should be applied in order to evaluate the quality of white wine.

  18. Oxalate metal complexes in aerosol particles: implications for the hygroscopicity of oxalate-containing particles

    Directory of Open Access Journals (Sweden)

    T. Furukawa

    2011-05-01

    Full Text Available Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to weaken the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA play an important role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is an important component of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca and zinc (Zn in aerosols collected at Tsukuba in Japan. Size-fractionated aerosol samples were collected for this purpose using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm were present as Ca and Zn oxalate complexes, respectively. Oxalic acid is hygroscopic and can thus increase the CCN activity of aerosol particles, while complexes with various polyvalent metal ions such as Ca and Zn are not hygroscopic, which cannot contribute to the increase of the CCN activity of aerosols. Based on the concentrations of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not always increase the hygroscopicity of aerosols in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is advisable that the cooling effect of organic aerosols should be estimated by including the

  19. Variation in oxalate and oxalate decarboxylase production by six species of brown and white rot fungi

    DEFF Research Database (Denmark)

    Hastrup, Anne Christine Steenkjær; Oliver, Jason; Howell, Caitlin

      Oxalic acid (C2O4H2), the strongest of the organic acids is produced by both brown and white rot decay fungi and has been connected to various aspects of brown- and white rot decay including the Fenton reaction (Green and Highley, 1997; Munir et al.,2001). Oxalic acid is secreted into the wood...... cell lumen where it quickly dissociates into hydrogen ions and oxalate, resulting in a pH decrease of the environment, and oxalate-cation complexes. Generally, brown rot fungi accumulate larger quantities of oxalic acid in the wood than white rot fungi. The amount of oxalic acid has been shown to vary...... of formic acid and CO2 (Makela et al., 2002). So far only a few species of brown rot fungi have been shown to accumulate this enzyme (Micales, 1995, Howell and Jellison, 2006).   The purpose of this study was to investigate the variation in the levels of soluble oxalate and total oxalate, in correlation...

  20. Sulfite-induced protein radical formation in LPS aerosol-challenged mice: Implications for sulfite sensitivity in human lung disease

    Directory of Open Access Journals (Sweden)

    Ashutosh Kumar

    2018-05-01

    Full Text Available Exposure to (bisulfite (HSO3– and sulfite (SO32– has been shown to induce a wide range of adverse reactions in sensitive individuals. Studies have shown that peroxidase-catalyzed oxidation of (bisulfite leads to formation of several reactive free radicals, such as sulfur trioxide anion (.SO3–, peroxymonosulfate (–O3SOO., and especially the sulfate (SO4. – anion radicals. One such peroxidase in neutrophils is myeloperoxidase (MPO, which has been shown to form protein radicals. Although formation of (bisulfite-derived protein radicals is documented in isolated neutrophils, its involvement and role in in vivo inflammatory processes, has not been demonstrated. Therefore, we aimed to investigate (bisulfite-derived protein radical formation and its mechanism in LPS aerosol-challenged mice, a model of non-atopic asthma. Using immuno-spin trapping to detect protein radical formation, we show that, in the presence of (bisulfite, neutrophils present in bronchoalveolar lavage and in the lung parenchyma exhibit, MPO-catalyzed oxidation of MPO to a protein radical. The absence of radical formation in LPS-challenged MPO- or NADPH oxidase-knockout mice indicates that sulfite-derived radical formation is dependent on both MPO and NADPH oxidase activity. In addition to its oxidation by the MPO-catalyzed pathway, (bisulfite is efficiently detoxified to sulfate by the sulfite oxidase (SOX pathway, which forms sulfate in a two-electron oxidation reaction. Since SOX activity in rodents is much higher than in humans, to better model sulfite toxicity in humans, we induced SOX deficiency in mice by feeding them a low molybdenum diet with tungstate. We found that mice treated with the SOX deficiency diet prior to exposure to (bisulfite had much higher protein radical formation than mice with normal SOX activity. Altogether, these results demonstrate the role of MPO and NADPH oxidase in (bisulfite-derived protein radical formation and show the involvement of

  1. High variability of the heterogeneous ice nucleation potential of oxalic acid dihydrate and sodium oxalate

    Directory of Open Access Journals (Sweden)

    R. Wagner

    2010-08-01

    Full Text Available The heterogeneous ice nucleation potential of airborne oxalic acid dihydrate and sodium oxalate particles in the deposition and condensation mode has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 244 and 228 K. Previous laboratory studies have highlighted the particular role of oxalic acid dihydrate as the only species amongst a variety of other investigated dicarboxylic acids to be capable of acting as a heterogeneous ice nucleus in both the deposition and immersion mode. We could confirm a high deposition mode ice activity for 0.03 to 0.8 μm sized oxalic acid dihydrate particles that were either formed by nucleation from a gaseous oxalic acid/air mixture or by rapid crystallisation of highly supersaturated aqueous oxalic acid solution droplets. The critical saturation ratio with respect to ice required for deposition nucleation was found to be less than 1.1 and the size-dependent ice-active fraction of the aerosol population was in the range from 0.1 to 22%. In contrast, oxalic acid dihydrate particles that had crystallised from less supersaturated solution droplets and had been allowed to slowly grow in a supersaturated environment from still unfrozen oxalic acid solution droplets over a time period of several hours were found to be much poorer heterogeneous ice nuclei. We speculate that under these conditions a crystal surface structure with less-active sites for the initiation of ice nucleation was generated. Such particles partially proved to be almost ice-inactive in both the deposition and condensation mode. At times, the heterogeneous ice nucleation ability of oxalic acid dihydrate significantly changed when the particles had been processed in preceding cloud droplet activation steps. Such behaviour was also observed for the second investigated species, namely sodium oxalate. Our experiments address the atmospheric scenario

  2. High variability of the heterogeneous ice nucleation potential of oxalic acid dihydrate and sodium oxalate

    Science.gov (United States)

    Wagner, R.; Möhler, O.; Saathoff, H.; Schnaiter, M.; Leisner, T.

    2010-08-01

    The heterogeneous ice nucleation potential of airborne oxalic acid dihydrate and sodium oxalate particles in the deposition and condensation mode has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 244 and 228 K. Previous laboratory studies have highlighted the particular role of oxalic acid dihydrate as the only species amongst a variety of other investigated dicarboxylic acids to be capable of acting as a heterogeneous ice nucleus in both the deposition and immersion mode. We could confirm a high deposition mode ice activity for 0.03 to 0.8 μm sized oxalic acid dihydrate particles that were either formed by nucleation from a gaseous oxalic acid/air mixture or by rapid crystallisation of highly supersaturated aqueous oxalic acid solution droplets. The critical saturation ratio with respect to ice required for deposition nucleation was found to be less than 1.1 and the size-dependent ice-active fraction of the aerosol population was in the range from 0.1 to 22%. In contrast, oxalic acid dihydrate particles that had crystallised from less supersaturated solution droplets and had been allowed to slowly grow in a supersaturated environment from still unfrozen oxalic acid solution droplets over a time period of several hours were found to be much poorer heterogeneous ice nuclei. We speculate that under these conditions a crystal surface structure with less-active sites for the initiation of ice nucleation was generated. Such particles partially proved to be almost ice-inactive in both the deposition and condensation mode. At times, the heterogeneous ice nucleation ability of oxalic acid dihydrate significantly changed when the particles had been processed in preceding cloud droplet activation steps. Such behaviour was also observed for the second investigated species, namely sodium oxalate. Our experiments address the atmospheric scenario that coating layers

  3. Sulphite metabolism; Metabolisme du sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Fromageot, P; Chapeville, F [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Although the formation of sulphite by micro-organisms was observed as early as 1914 by Neuberg, it was only in 1932 that Nightingale showed it to be present inside cells, in the case of tomato leaf stalks, its formation being due to the reaction: SO{sub 3}H{sup -} + (S{sub 2}O{sub 3}){sub 2}{sup --} {yields} S{sub 2}O{sub 3}{sup --} + O{sub 3}S{sub 2}O{sub 3}{sup --}. The presence of the thiosulphate formed was shown by the high refractive index of its barium salt. Today we have a certain amount of data concerning the formation and use of sulphite in the living cell, even through the knowledge is still incomplete. In this article we will describe and discuss the facts which are known, with particular reference to the oxidation of sulphite. (author) [French] Si la formation de sulfite par des micro-organismes a ete observee des 1914 par Neuberg, sa presence a l'interieur des cellules a ete demontree pour la premiere fois par Nightingale en 1932, dans des tiges et des feuilles de tomates, par la reaction: SO{sub 3}H{sup -} + (S{sub 2}O{sub 3}){sub 2}{sup --} {yields} S{sub 2}O{sub 3}{sup --} + O{sub 3}S{sub 2}O{sub 3}{sup --}. Le thiosulfate forme etait mis en evidence par l'indice de refraction eleve de son sel de baryum. Aujourd'hui on possede un certain nombre de donnees, cependant encore tres incompletes, sur la formation du sulfite et son utilisation par la cellule vivante. Dans cet expose nous decrirons et discuterons quelques-unes de ces acquisitions, tout particulierement celles relatives a l'oxydation du sulfite. (auteur)

  4. Avoiding total reduced sulfur (TRS) emissions from sodium sulfite pulping recovery processes

    International Nuclear Information System (INIS)

    Norman, J.C.; Sell, N.J.; Ciriacks, J.C.

    1990-01-01

    This paper reports that one of the current trends in paper-making with cellulose pulping is the use of high-yield processes. With yields greater than 65%, these processes include mechanical pulps (groundwood and thermomechanical pulps or TMP), and semichemical types (chemi-TMP or CTMP). Groundwood and TMP make up about 10% of North American pulp production. Semichemical pulp makes up about 7% and is mostly used for corrugating medium. High-yield pulping for linerboard, particularly using the alkaline sulfite process, is also likely to be used in the future. High-yield pulping is based primarily on the sulfite process using mostly sodium-based chemicals. A disadvantage of this process is the unavailability of a recovery system for the inorganic pulping chemicals. Generally, mills have not accepted any particular recovery system for this process. For this and other reasons, sulfite processes constitute only 3-4% of the total North American pulp production. If high-yield processes continue to increase in popularity, a sodium sulfite chemical recovery system will be needed. A number of chemical recovery systems have been developed in the past 30 years for sodium-based sulfite pulping processes, with most of the mills successfully using this process located in Scandinavia

  5. Metabolic Conversion of l-Ascorbic Acid to Oxalic Acid in Oxalate-accumulating Plants 1

    Science.gov (United States)

    Yang, Joan C.; Loewus, Frank A.

    1975-01-01

    l-Ascorbic acid-1-14C and its oxidation product, dehydro-l-ascorbic acid, produced labeled oxalic acid in oxalate-accumulating plants such as spinach seedlings (Spinacia oleracea) and the detached leaves of woodsorrel (Oxalis stricta and O. oregana), shamrock (Oxalis adenopylla), and begonia (Begonia evansiana). In O. oregana, conversion occurred equally well in the presence or absence of light. This relationship between l-ascorbic acid metabolism and oxalic acid formation must be given careful consideration in attempts to explain oxalic accumulation in plants. PMID:16659288

  6. Role of pH on the acute toxicity of sulfite in water. [Carassius auratus; Leistes reticulatus

    Energy Technology Data Exchange (ETDEWEB)

    Sano, H.

    1976-01-01

    The toxicity of sulfite to fish decreases with increasing pH value, because the HSO/sub 3//sup -/ ion is more toxic than the SO/sub 3//sup 2 -/ ion. An effective sulfite concentration S/sub eff/ which is proportional to the toxicity on fish is expressed by the following equation: S/sub eff/ = (HSO/sub 3//sup -/) + f(SO/sub 3//sup 2 -/), where f is a coefficient which expresses the change of toxicity of sulfite depending on the pH of the water, and varies for each species of fish. For goldfish, owing to the very small toxic contribution of SO/sub 3//sup 2 -/ ion (f = 0.07), the pH dependence of the toxicity of sulfite on pH was so strong that sulfite seemed almost non-toxic in basic solution. However, f for guppy is somewhat larger (f = 0.20) so that the toxicity of sulfite weakly depends on the pH value of water.

  7. Nitrite, nitrite alternatives, and the control of Clostridium botulinum in cured meats.

    Science.gov (United States)

    Pierson, M D; Smoot, L A

    1982-01-01

    Historically, nitrite has been a component of meat-curing additives for several centuries. In recent years the safety of nitrite as an additive in cured meats has been questioned mainly because of the possible formation of carcinogenic nitrosamines. Nitrite has many important functions in meat curing including its role in color development, flavor, antioxidant properties, and antimicrobial activity. The inhibition of Clostridium botulinum growth and toxin production is an especially important antimicrobial property of nitrite. This review discusses the effects of processing, curing ingredients (especially nitrite), and storage of cured meats in relation to the control of C. botulinum. If nitrite is eliminated from cured meats or the level of usage decreased, then alternatives for the antibotulinal function of nitrite need to be considered. Several potential alternatives including sorbates, parabens, and biological acidulants are discussed.

  8. Analytical Study of Oxalates Coprecipitation

    Directory of Open Access Journals (Sweden)

    Liana MARTA

    2003-03-01

    Full Text Available The paper deals with the establishing of the oxalates coprecipitation conditions in view of the synthesis of superconducting systems. A systematic analytical study of the oxalates precipitation conditions has been performed, for obtaining superconducting materials, in the Bi Sr-Ca-Cu-O system. For this purpose, the formulae of the precipitates solubility as a function of pH and oxalate excess were established. The possible formation of hydroxo-complexes and soluble oxalato-complexes was taken into account. A BASIC program was used for tracing the precipitation curves. The curves of the solubility versus pH for different oxalate excess have plotted for the four oxalates, using a logaritmic scale. The optimal conditions for the quantitative oxalate coprecipitation have been deduced from the diagrams. The theoretical curves were confirmed by experimental results. From the precursors obtained by this method, the BSCCO superconducting phases were obtained by an appropriate thermal treatment. The formation of the superconducting phases was identified by X-ray diffraction analysis.

  9. Oxalate: Effect on calcium absorbability

    International Nuclear Information System (INIS)

    Heaney, R.P.; Weaver, C.M.

    1989-01-01

    Absorption of calcium from intrinsically labeled Ca oxalate was measured in 18 normal women and compared with absorption of Ca from milk in these same subjects, both when the test substances were ingested in separate meals and when ingested together. Fractional Ca absorption from oxalate averaged 0.100 +/- 0.043 when ingested alone and 0.140 +/- 0.063 when ingested together with milk. Absorption was, as expected, substantially lower than absorption from milk (0.358 +/- 0.113). Nevertheless Ca oxalate absorbability in these women was higher than we had previously found for spinach Ca. When milk and Ca oxalate were ingested together, there was no interference of oxalate in milk Ca absorption and no evidence of tracer exchange between the two labeled Ca species

  10. The bioavailability of oxalate from Oca (Oxalis tuberosa).

    Science.gov (United States)

    Albihn, P B; Savage, G P

    2001-08-01

    It is believed that soluble oxalate has higher bioavailability than insoluble oxalate. Oca (Oxalis tuberosa) is moderately high in oxalate and contains oxalate in soluble form only. We estimated the bioavailability of oxalate in oca based on the urinary excretion of oxalate after oxalate loading with oca to estimate the bioavailability of oxalate in oca. We also clarified whether bioavailability differs in various oxalate loads from the same food source and studied the effect of an additional calcium source on the bioavailability of oxalate from oca. Four men and 4 women ingested 50, 100 and 150 gm. oca as well as 100 gm. oca with 100 gm. sour cream. Oxalate was measured in a 6-hour urine sample from each volunteer. The mean bioavailability of oxalate from oca plus or minus standard deviation was 1.44% +/- 1.31% during the 6-hour period after intake. There was no significant difference in oxalate bioavailability among oxalate intake levels in this study, although oca consumption with sour cream significantly decreased the uptake of oxalate (p oca appears to be similar to that in spinach. However, bioavailability varies among individuals and depends on other constituents of a combined meal.

  11. Calcium oxalate stone and gout.

    Science.gov (United States)

    Marickar, Y M Fazil

    2009-12-01

    Gout is well known to be produced by increased uric acid level in blood. The objective of this paper is to assess the relationship between gout and calcium oxalate stone formation in the humans. 48 patients with combination of gout and calcium oxalate stone problem were included. The biochemical values of this group were compared with 38 randomly selected uric acid stone patients with gout, 43 stone patients with gout alone, 100 calcium oxalate stone patients without gout and 30 controls, making a total of 259 patients. Various biochemical parameters, namely serum calcium, phosphorus and uric acid and 24-h urine calcium, phosphorus, uric acid, oxalate, citrate and magnesium were analysed. ANOVA and Duncan's multiple-range tests were performed to assess statistical significance of the variations. The promoters of stone formation, namely serum calcium (P stone patients and gouty calcium oxalate stone patients compared to the non-gouty patients and controls. Urine oxalate (P stones patients. The inhibitor urine citrate (P stone gouty patients, followed by the gouty uric acid stone formers and gouty calcium oxalate stone patients. The high values of promoters, namely uric acid and calcium in the gouty stone patients indicate the tendency for urinary stone formation in the gouty stone patients. There is probably a correlation between gout and calcium oxalate urinary stone. We presume this mechanism is achieved through the uric acid metabolism. The findings point to the summation effect of metabolic changes in development of stone disease.

  12. Case studies on sugar production from underutilized woody biomass using sulfite chemistry

    Science.gov (United States)

    J.Y. Zhu; M. Subhosh Chandra; Roland Gleisner; William Gilles; Johnway Gao; Gevan Marrs; Dwight Anderson; John Sessions

    2015-01-01

    We examined two case studies to demonstrate the advantages of sulfite chemistry for pretreating underutilized woody biomass to produce sugars through enzymatic saccharification. In the first case study, we evaluated knot rejects from a magnesium-basedsulfite mill for direct enzymatic sugar production.We found that the sulfite mill rejects are an excellent feedstock for...

  13. The anti-browning agent sulfite inactivates Agaricus bisporus tyrosinase through covalent modification of the copper-B site

    NARCIS (Netherlands)

    Kuijpers, T.F.M.; Gruppen, H.; Sforza, S.; Berkel, van W.J.H.; Vincken, J.P.

    2013-01-01

    Sulfite salts are widely used as antibrowning agents in food processing. Nevertheless, the exact mechanism by which sulfite prevents enzymatic browning has remained unknown. Here, we show that sodium hydrogen sulfite (NaHSO3 ) irreversibly blocks the active site of tyrosinase from the edible

  14. Decomposition of oxalate precipitates by photochemical reaction

    International Nuclear Information System (INIS)

    Jae-Hyung Yoo; Eung-Ho Kim

    1999-01-01

    A photo-radiation method was applied to decompose oxalate precipitates so that it can be dissolved into dilute nitric acid. This work has been studied as a part of partitioning of minor actinides. Minor actinides can be recovered from high-level wastes as oxalate precipitates, but they tend to be coprecipitated together with lanthanide oxalates. This requires another partitioning step for mutual separation of actinide and lanthanide groups. In this study, therefore, some experimental work of photochemical decomposition of oxalate was carried out to prove its feasibility as a step of partitioning process. The decomposition of oxalic acid in the presence of nitric acid was performed in advance in order to understand the mechanistic behaviour of oxalate destruction, and then the decomposition of neodymium oxalate, which was chosen as a stand-in compound representing minor actinide and lanthanide oxalates, was examined. The decomposition rate of neodymium oxalate was found as 0.003 mole/hr at the conditions of 0.5 M HNO 3 and room temperature when a mercury lamp was used as a light source. (author)

  15. In vivo oxalate degradation by liposome encapsulated oxalate oxidase in rat model of hyperoxaluria

    Directory of Open Access Journals (Sweden)

    Tulika Dahiya

    2013-01-01

    Interpretation & conclusions: EMA-oxalate oxidase encapsulated liposome caused oxalate degradation in experimental hyperoxaluria indicating that the enzyme could be used as a therapeutic agent in hyperoxaluria leading to urinary stones.

  16. Recovery Ce from Ce - TBP Used Oxalic Acid

    International Nuclear Information System (INIS)

    Purwani, MV; Subagiono, R.; Suyanti

    2007-01-01

    Recovery or stripping Ce from Ce - TBP product of monazite sand used oxalic acid. Ce - TBP as organic phase and oxalic acid as aqueous phase and as strong precipitant compound to precipitate metal element. The stripping product as Ce - oxalic precipitate. The influence parameter were percentage of oxalic acid, volume ratio of Ce-TBP with oxalic acid, time and rate of stripping. At stripping of 25 ml Ce - TBP used oxalic acid, the optimum condition were achieve at using 5% oxalic acid, volume ratio of Ce - TBP : 5% oxalic acid = 1 : 1, time of stripping 7.5 minute and rate of stripping 150 rpm. At the optimum condition was obtained the recovery efficiency was 100%. (author)

  17. Study of oxalic acid effect on equilibrium and kinetics of isotopic exchange between penta- and hexavalent neptunium in nitric acid solutions

    International Nuclear Information System (INIS)

    Nikitenko, S.I.; Ionnikova, N.I.

    1989-01-01

    Spectrophotometry at 25 deg C and ionic force μ=1.0 mol/l (KNO 3 +HNO 3 ) was used to show that at HNO 3 concentration 0.1-1.0 mol/l H 2 C 2 O 4 introduction to nitric acid solutions of Np 5+ in the presence of nitrite-ion resulted in the shift of equilibrium between Np 5+ and Np 6+ to the side of Np 6+ accumulation. The presence of H 2 C 2 O 4 at HNO 3 concentration > 1.0 mol/l doesn't affect the equilibrium position. The values of nominal equilibrium constant at different HNO 3 and H 2 C 2 O 4 concentrations were calculated. It was found that isotope exchange ( 239 Np/ 237 Np) between Np 5+ and Np 6+ in oxalate solutions proceeded more slowly than in oxalate absence. Rate constants of isotope exchange calculated at 9 deg C, μ=1.0 mol/l (KNO 3 ), H 2 C 2 O 4 concentration 0.01 mol/l and pH=2.2 and 3.5 are equal to 0.49x10 3 and 0.67x10 2 l/mol·min respectively. Mechanism of isotope exchange including electron transport between Np 5+ and Np 6+ oxalate complexes is suggested

  18. High variability of the heterogeneous ice nucleation potential of oxalic acid dihydrate and sodium oxalate

    OpenAIRE

    R. Wagner; O. Möhler; H. Saathoff; M. Schnaiter; T. Leisner

    2010-01-01

    The heterogeneous ice nucleation potential of airborne oxalic acid dihydrate and sodium oxalate particles in the deposition and condensation mode has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 244 and 228 K. Previous laboratory studies have highlighted the particular role of oxalic acid dihydrate as the only species amongst a variety of other investigated dicarboxylic acids to ...

  19. The comparability of oxalate excretion and oxalate:creatinine ratio in the investigation of primary hyperoxaluria: review of data from a referral centre.

    Science.gov (United States)

    Clifford-Mobley, Oliver; Tims, Christopher; Rumsby, Gill

    2015-01-01

    Urine oxalate measurement is an important investigation in the evaluation of renal stone disease. Primary hyperoxaluria (PH) is a rare inherited metabolic disease characterised by persistently elevated urine oxalate, but the diagnosis may be missed in adults until renal failure has developed. Urine oxalate results were reviewed to compare oxalate:creatinine ratio and oxalate excretion, and to estimate the potential numbers of undiagnosed PH. Urine oxalate results from August 2011 to April 2013 were reviewed. Oxalate excretion and oxalate:creatinine ratio were evaluated for 24 h collections and ratio alone for spot urine samples. Oxalate:creatinine ratio and oxalate excretion were moderately correlated (R=0.63) in 24-h urine collections from patients aged 18 years and above. Sex-related differences were found requiring implementation of male and female reference ranges for oxalate:creatinine ratio. Of samples with both ratio and excretion above the reference range, 7% came from patients with confirmed PH. There were 24 patients with grossly elevated urine oxalate who had not been evaluated for PH. Oxalate:creatinine ratio and oxalate excretion were discordant in many patients, which is likely to be a result of intra-individual variation in creatinine output and imprecision in the collection itself. Some PH patients had urine oxalate within the reference range on occasion, and therefore it is not possible to exclude PH on the finding of a single normal result. A significant number of individuals had urine oxalate results well above the reference range who potentially have undiagnosed PH and are consequently at risk of renal failure. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  20. Nitrate decreases xanthine oxidoreductase-mediated nitrite reductase activity and attenuates vascular and blood pressure responses to nitrite.

    Science.gov (United States)

    Damacena-Angelis, Célio; Oliveira-Paula, Gustavo H; Pinheiro, Lucas C; Crevelin, Eduardo J; Portella, Rafael L; Moraes, Luiz Alberto B; Tanus-Santos, Jose E

    2017-08-01

    Nitrite and nitrate restore deficient endogenous nitric oxide (NO) production as they are converted back to NO, and therefore complement the classic enzymatic NO synthesis. Circulating nitrate and nitrite must cross membrane barriers to produce their effects and increased nitrate concentrations may attenuate the nitrite influx into cells, decreasing NO generation from nitrite. Moreover, xanthine oxidoreductase (XOR) mediates NO formation from nitrite and nitrate. However, no study has examined whether nitrate attenuates XOR-mediated NO generation from nitrite. We hypothesized that nitrate attenuates the vascular and blood pressure responses to nitrite either by interfering with nitrite influx into vascular tissue, or by competing with nitrite for XOR, thus inhibiting XOR-mediated NO generation. We used two independent vascular function assays in rats (aortic ring preparations and isolated mesenteric arterial bed perfusion) to examine the effects of sodium nitrate on the concentration-dependent responses to sodium nitrite. Both assays showed that nitrate attenuated the vascular responses to nitrite. Conversely, the aortic responses to the NO donor DETANONOate were not affected by sodium nitrate. Further confirming these results, we found that nitrate attenuated the acute blood pressure lowering effects of increasing doses of nitrite infused intravenously in freely moving rats. The possibility that nitrate could compete with nitrite and decrease nitrite influx into cells was tested by measuring the accumulation of nitrogen-15-labeled nitrite ( 15 N-nitrite) by aortic rings using ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS). Nitrate exerted no effect on aortic accumulation of 15 N-nitrite. Next, we used chemiluminescence-based NO detection to examine whether nitrate attenuates XOR-mediated nitrite reductase activity. Nitrate significantly shifted the Michaelis Menten saturation curve to the right, with a 3-fold increase in the

  1. Assessment of dietary exposure in the French population to 13 selected food colours, preservatives, antioxidants, stabilizers, emulsifiers and sweeteners.

    Science.gov (United States)

    Bemrah, Nawel; Leblanc, Jean-Charles; Volatier, Jean-Luc

    2008-01-01

    The results of French intake estimates for 13 food additives prioritized by the methods proposed in the 2001 Report from the European Commission on Dietary Food Additive Intake in the European Union are reported. These 13 additives were selected using the first and second tiers of the three-tier approach. The first tier was based on theoretical food consumption data and the maximum permitted level of additives. The second tier used real individual food consumption data and the maximum permitted level of additives for the substances which exceeded the acceptable daily intakes (ADI) in the first tier. In the third tier reported in this study, intake estimates were calculated for the 13 additives (colours, preservatives, antioxidants, stabilizers, emulsifiers and sweeteners) according to two modelling assumptions corresponding to two different food habit scenarios (assumption 1: consumers consume foods that may or may not contain food additives, and assumption 2: consumers always consume foods that contain additives) when possible. In this approach, real individual food consumption data and the occurrence/use-level of food additives reported by the food industry were used. Overall, the results of the intake estimates are reassuring for the majority of additives studied since the risk of exceeding the ADI was low, except for nitrites, sulfites and annatto, whose ADIs were exceeded by either children or adult consumers or by both populations under one and/or two modelling assumptions. Under the first assumption, the ADI is exceeded for high consumers among adults for nitrites and sulfites (155 and 118.4%, respectively) and among children for nitrites (275%). Under the second assumption, the average nitrites dietary exposure in children exceeds the ADI (146.7%). For high consumers, adults exceed the nitrite and sulfite ADIs (223 and 156.4%, respectively) and children exceed the nitrite, annatto and sulfite ADIs (416.7, 124.6 and 130.6%, respectively).

  2. Hydroxyproline Metabolism and Oxalate Synthesis in Primary Hyperoxaluria.

    Science.gov (United States)

    Fargue, Sonia; Milliner, Dawn S; Knight, John; Olson, Julie B; Lowther, W Todd; Holmes, Ross P

    2018-06-01

    Background Endogenous oxalate synthesis contributes to calcium oxalate stone disease and is markedly increased in the inherited primary hyperoxaluria (PH) disorders. The incomplete knowledge regarding oxalate synthesis complicates discovery of new treatments. Hydroxyproline (Hyp) metabolism results in the formation of oxalate and glycolate. However, the relative contribution of Hyp metabolism to endogenous oxalate and glycolate synthesis is not known. Methods To define this contribution, we performed primed, continuous, intravenous infusions of the stable isotope [ 15 N, 13 C 5 ]-Hyp in nine healthy subjects and 19 individuals with PH and quantified the levels of urinary 13 C 2 -oxalate and 13 C 2 -glycolate formed using ion chromatography coupled to mass detection. Results The total urinary oxalate-to-creatinine ratio during the infusion was 73.1, 70.8, 47.0, and 10.6 mg oxalate/g creatinine in subjects with PH1, PH2, and PH3 and controls, respectively. Hyp metabolism accounted for 12.8, 32.9, and 14.8 mg oxalate/g creatinine in subjects with PH1, PH2, and PH3, respectively, compared with 1.6 mg oxalate/g creatinine in controls. The contribution of Hyp to urinary oxalate was 15% in controls and 18%, 47%, and 33% in subjects with PH1, PH2, and PH3, respectively. The contribution of Hyp to urinary glycolate was 57% in controls, 30% in subjects with PH1, and synthesis in individuals with PH2 and PH3. In patients with PH1, who have the highest urinary excretion of oxalate, the major sources of oxalate remain to be identified. Copyright © 2018 by the American Society of Nephrology.

  3. Co-precipitation of plutonium(IV) and americium(III) from nitric acid-oxalic acid solutions with bismuth oxalate

    International Nuclear Information System (INIS)

    Pius, I.C.; Noronha, D.M.; Chaudhury, Satyajeet

    2017-01-01

    Co-precipitation of plutonium and americium from nitric acid-oxalic acid solutions with bismuth oxalate has been investigated for the removal of these long lived α-active nuclides from waste solutions. Effect of concentration of bismuth and oxalic acid on the co-precipitation of Pu(IV) from 3 M HNO_3 has been investigated. Similar experiments were also carried out from 3.75 M HNO_3 on co-precipitation of Am(III) to optimize the conditions of precipitation. Strong co-precipitation of Pu(IV) and Am(III) with bismuth oxalate indicate feasibility of treatment of plutonium and americium bearing waste solutions. (author)

  4. Oxalates in oca (New Zealand yam) (Oxalis tuberosa Mol.).

    Science.gov (United States)

    Ross, A B; Savage, G P; Martin, R J; Vanhanen, L

    1999-12-01

    Oca (Oxalis tuberosa Mol.) or New Zealand yam, in common with other members of this genus, contains oxalate, an antinutritive factor. Twelve South American and two New Zealand cultivars of oca were analyzed for total and soluble oxalate contents of the tubers. The range of total oxalate levels was 92-221 mg/100 g of fresh weight. Levels of soluble and total oxalate extracted from the tubers were not significantly different, suggesting that no calcium oxalate is formed in the tubers. The oxalate concentrations obtained in this study for oca suggest that previously reported values are too low and that oca is a moderately high oxalate-containing food. This is the first report of a tuber crop containing moderate to high levels of soluble oxalates in the tubers and no insoluble oxalates.

  5. Isolation of oxalic acid tolerating fungi and decipherization of its potential to control Sclerotinia sclerotiorum through oxalate oxidase like protein.

    Science.gov (United States)

    Yadav, Shivani; Srivastava, Alok K; Singh, Dhanajay P; Arora, Dilip K

    2012-11-01

    Oxalic acid plays major role in the pathogenesis by Sclerotinia sclerotiorum; it lowers the pH of nearby environment and creates the favorable condition for the infection. In this study we examined the degradation of oxalic acid through oxalate oxidase and biocontrol of Sclerotinia sclerotiorum. A survey was conducted to collect the rhizospheric soil samples from Indo-Gangetic Plains of India to isolate the efficient fungal strains able to tolerate oxalic acid. A total of 120 fungal strains were isolated from root adhering soils of different vegetable crops. Out of 120 strains a total of 80 isolates were able to grow at 10 mM of oxalic acid whereas only 15 isolates were grow at 50 mM of oxalic acid concentration. Then we examined the antagonistic activity of the 15 isolates against Sclerotinia sclerotiorum. These strains potentially inhibit the growth of the test pathogen. A total of three potential strains and two standard cultures of fungi were tested for the oxalate oxidase activity. Strains S7 showed the maximum degradation of oxalic acid (23 %) after 60 min of incubation with fungal extract having oxalate oxidase activity. Microscopic observation and ITS (internally transcribed spacers) sequencing categorized the potential fungal strains into the Aspergillus, Fusarium and Trichoderma. Trichoderma sp. are well studied biocontrol agent and interestingly we also found the oxalate oxidase type activity in these strains which further strengthens the potentiality of these biocontrol agents.

  6. Amperometric Determination of Sulfite by Gas Diffusion- Sequential Injection with Boron-Doped Diamond Electrode

    Directory of Open Access Journals (Sweden)

    Orawon Chailapakul

    2008-03-01

    Full Text Available A gas diffusion sequential injection system with amperometric detection using aboron-doped diamond electrode was developed for the determination of sulfite. A gasdiffusion unit (GDU was used to prevent interference from sample matrices for theelectrochemical measurement. The sample was mixed with an acid solution to generategaseous sulfur dioxide prior to its passage through the donor channel of the GDU. Thesulfur dioxide diffused through the PTFE hydrophobic membrane into a carrier solution of 0.1 M phosphate buffer (pH 8/0.1% sodium dodecyl sulfate in the acceptor channel of theGDU and turned to sulfite. Then the sulfite was carried to the electrochemical flow cell anddetected directly by amperometry using the boron-doped diamond electrode at 0.95 V(versus Ag/AgCl. Sodium dodecyl sulfate was added to the carrier solution to preventelectrode fouling. This method was applicable in the concentration range of 0.2-20 mgSO32−/L and a detection limit (S/N = 3 of 0.05 mg SO32−/L was achieved. This method wassuccessfully applied to the determination of sulfite in wines and the analytical resultsagreed well with those obtained by iodimetric titration. The relative standard deviations forthe analysis of sulfite in wines were in the range of 1.0-4.1 %. The sampling frequency was65 h−1.

  7. Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II oxalate precursor layers

    Directory of Open Access Journals (Sweden)

    Kai Rückriem

    2016-06-01

    Full Text Available Copper(II oxalate grown on carboxy-terminated self-assembled monolayers (SAM using a step-by-step approach was used as precursor for the electron-induced synthesis of surface-supported copper nanoparticles. The precursor material was deposited by dipping the surfaces alternately in ethanolic solutions of copper(II acetate and oxalic acid with intermediate thorough rinsing steps. The deposition of copper(II oxalate and the efficient electron-induced removal of the oxalate ions was monitored by reflection absorption infrared spectroscopy (RAIRS. Helium ion microscopy (HIM reveals the formation of spherical nanoparticles with well-defined size and X-ray photoelectron spectroscopy (XPS confirms their metallic nature. Continued irradiation after depletion of oxalate does not lead to further particle growth giving evidence that nanoparticle formation is primarily controlled by the available amount of precursor.

  8. (Dimethylphosphorylmethanaminium hydrogen oxalate–oxalic acid (2/1

    Directory of Open Access Journals (Sweden)

    Sebastian Bialek

    2014-03-01

    Full Text Available The reaction of (dimethylphosphorylmethanamine (dpma with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4−·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-molecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16° whereas the oxalic acid molecule shows a significantly smaller bend angle (∼7°. In the crystal, the components are connected by strong O—H...O and much weaker N—H...O hydrogen bonds, leading to the formation of layers extending parallel to (001. The structure was refined from a racemically twinned crystal with twin components in an approximate 1:1 ratio.

  9. Mixing state of oxalic acid containing particles in the rural area of Pearl River Delta, China: implications for the formation mechanism of oxalic acid

    Directory of Open Access Journals (Sweden)

    C. Cheng

    2017-08-01

    Full Text Available The formation of oxalic acid and its mixing state in atmospheric particulate matter (PM were studied using a single-particle aerosol mass spectrometer (SPAMS in the summer and winter of 2014 in Heshan, a supersite in the rural area of the Pearl River Delta (PRD region in China. Oxalic-acid-containing particles accounted for 2.5 and 2.7 % in total detected ambient particles in summer and winter, respectively. Oxalic acid was measured in particles classified as elemental carbon (EC, organic carbon (OC, elemental and organic carbon (ECOC, biomass burning (BB, heavy metal (HM, secondary (Sec, sodium-potassium (NaK, and dust. Oxalic acid was found predominantly mixing with sulfate and nitrate during the whole sampling period, likely due to aqueous-phase reactions. In summer, oxalic-acid-containing particle number and ozone concentration followed a very similar trend, which may reflect the significant contribution of photochemical reactions to oxalic acid formation. The HM particles were the most abundant oxalic acid particles in summer and the diurnal variations in peak area of iron and oxalic acid show opposite trends, which suggests a possible loss of oxalic acid through the photolysis of iron oxalato-complexes during the strong photochemical activity period. In wintertime, carbonaceous particles contained a substantial amount of oxalic acid as well as abundant carbon clusters and BB markers. The general existence of nitric acid in oxalic-acid-containing particles indicates an acidic environment during the formation process of oxalic acid. The peak areas of nitrate, sulfate and oxalic had similar temporal change in the carbonaceous type oxalic acid particles, and the organosulfate-containing oxalic acid particles correlated well with total oxalic acid particles during the haze episode, which suggests that the formation of oxalic acid is closely associated with the oxidation of organic precursors in the aqueous phase.

  10. Dietary Nitrite: from menace to marvel

    Directory of Open Access Journals (Sweden)

    Nathan S. Bryan

    2016-11-01

    Full Text Available The health benefits of nitrite are now indisputable when administered in a clinical setting for specific diseases. Currently, most published reports identify the production of nitric oxide (NO as the mechanism of action for nitrite. Basic science, in addition to clinical studies, demonstrate that nitrite and/or nitrate cannot restore NO homeostasis as an endothelium independent source of NO that may be a redundant system for endogenous NO production. Nitrate must first be reduced to nitrite by oral commensal bacteria; nitrite can then be further reduced to NO along the physiological oxygen gradient. But despite decades of rigorous research on sodium nitrate’s safety and efficacy as a curing agent, sodium nitrite is still regarded by many as a toxic undesirable food additive. However, research within the biomedical science community has revealed enormous therapeutic benefits of nitrite which are being developed as novel therapies for conditions associated with nitric oxide insufficiency. Thus, this review will highlight the fundamental biochemistry of nitrite in human physiology and provide evidence that nitrite be considered an essential nutrient. Foods or diets enriched with nitrite can have profound positive health benefits.

  11. Dating oxalate minerals in rock surface deposits

    International Nuclear Information System (INIS)

    Watchman, A.

    2001-01-01

    Oxalate minerals are found associated with rocks, mineral coatings, micro-organisms, plants and animals. They are important in archaeology because they have been found intimately associated with organic binders in prehistoric paints. Oxalate minerals also accumulate in the coatings on rock shelter walls and fallen ceiling slabs where they form the natural backing supports for painting and opaque laminates covering engravings. Though the relationship between anthropogenic activity in a rock shelter and oxalate formation is often uncertain, the radiocarbon age of the oxalate may provide the only means for determining the antiquity of a rock painting or engraving. This paper examines the history of dating oxalate minerals at archaeological sites and provides insights into achieving reliable age estimates. (author). 37 refs., 1 fig., 2 tabs

  12. Cerium oxalate precipitation

    International Nuclear Information System (INIS)

    Chang, T.P.

    1987-02-01

    Cerium, a nonradioactive, common stand-in for plutonium in development work, has been used to simulate several plutonium precipitation processes at the Savannah River Laboratory. There are similarities between the plutonium trifluoride and the cerium oxalate precipitations in particle size and extent of plating, but not particle morphology. The equilibrium solubility, precipitation kinetics, particle size, extent of plating, and dissolution characteristics of cerium oxalate have been investigated. Interpretations of particle size and plating based on precipitation kinetics (i.e., nucleation and crystal growth) are presented. 16 refs., 7 figs., 6 tabs

  13. Pathology and Epidemiology of Oxalate Nephrosis in Cheetahs.

    Science.gov (United States)

    Mitchell, Emily P; Church, Molly E; Nemser, Sarah M; Yakes, Betsy Jean; Evans, Eric R; Reimschuessel, Renate; Lemberger, Karin; Thompson, Peter N; Terio, Karen A

    2017-11-01

    To investigate cases of acute oxalate nephrosis without evidence of ethylene glycol exposure, archived data and tissues from cheetahs ( Acinonyx jubatus) from North America ( n = 297), southern Africa ( n = 257), and France ( n = 40) were evaluated. Renal and gastrointestinal tract lesions were characterized in a subset of animals with ( n = 100) and without ( n = 165) oxalate crystals at death. Crystals were confirmed as calcium oxalate by Raman spectroscopy in 45 of 47 cheetahs tested. Crystals were present in cheetahs from 3.7 months to 15.9 years old. Cheetahs younger than 1.5 years were less likely to have oxalates than older cheetahs ( P = .034), but young cheetahs with oxalates had more oxalate crystals than older cheetahs ( P Cheetahs with oxalate crystals were more likely to have renal amyloidosis, interstitial nephritis, or colitis and less likely to have glomerular loop thickening or gastritis than those without oxalates. Crystal number was positively associated with renal tubular necrosis ( P ≤ .001), regeneration ( P = .015), and casts ( P ≤ .001) but inversely associated with glomerulosclerosis, renal amyloidosis, and interstitial nephritis. Crystal number was unrelated to the presence or absence of colitis and was lower in southern African than American and European animals ( P = .01). This study found no evidence that coexisting chronic renal disease (amyloidosis, interstitial nephritis, or glomerulosclerosis), veno-occlusive disease, gastritis, or enterocolitis contributed significantly to oxalate nephrosis. Oxalate-related renal disease should be considered as a potential cause of acute renal failure, especially in young captive cheetahs. The role of location, diet, stress, and genetic predisposition in the pathogenesis of oxalate nephrosis in cheetahs warrants further study.

  14. Precipitation of plutonium oxalate from homogeneous solutions

    International Nuclear Information System (INIS)

    Rao, V.K.; Pius, I.C.; Subbarao, M.; Chinnusamy, A.; Natarajan, P.R.

    1986-01-01

    A method for the precipitation of plutonium(IV) oxalate from homogeneous solutions using diethyl oxalate is reported. The precipitate obtained is crystalline and easily filterable with yields in the range of 92-98% for precipitations involving a few mg to g quantities of plutonium. Decontamination factors for common impurities such as U(VI), Am(III) and Fe(III) were determined. TGA and chemical analysis of the compound indicate its composition as Pu(Csub(2)Osub(4))sub(2).6Hsub(2)O. Data are obtained on the solubility of the oxalate in nitric acid and in mixtures of nitric acid and oxalic acid of varying concentrations. Green PuOsub(2) obtained by calcination of the oxalate has specifications within the recommended values for trace foreign substances such as chlorine, fluorine, carbon and nitrogen. (author)

  15. Update on probiotics for the treatment of calcium oxalate stones

    Directory of Open Access Journals (Sweden)

    Di ZHANG

    2016-09-01

    Full Text Available Urolithiasis is one of the common diseases in urinary system, among which calcium oxalate stone is the most common one with a high recurrence rate. An important pathological factor for the formation of calcium oxalate stone is the increased absorption of oxalate from intestine, which leads to a high urine oxalate concentration. Intestinal bacteria known to be able to degrade oxalate includes Oxalobacter formigenes, Enterococcus faecalis, Escherichia coli, Eubacterium lentum, Providencia rettgeri, Lactobacillus and Bifidobacterium species, etc. Among those, Oxalobacter formigenes is the first oxalate-degrading obligate anaerobe found in human, while the rest are just conditioned bacteria with the function to degrade intestinal oxalate. There are three kinds of enzymes in Oxalobacter formigenes involved in the metabolism of oxalate, namely oxalate-formate antiporter (OxlT, formyl-CoA transferase (Frc and oxalyl-CoA decarboxylase (Oxc. Animal experiments have verified that Oxalobacter formigenes could reduce intestinal oxalate absorption by promoting the secretion of oxalate and degradation as well, thus decrease the excretion of urine oxalate. The present review will focus on the research progress of probiotics treatment for the calcium oxalate stones so as to provide reference for further research and development. DOI: 10.11855/j.issn.0577-7402.2016.08.16

  16. Isolation of nitrite-degrading strains from Douchi and their application to degrade high nitrite in Jiangshui.

    Science.gov (United States)

    Guo, Xing; Liu, Bianfang; Gao, Lina; Zhou, Yuan; Shan, Yuanyuan; Lü, Xin

    2018-06-01

    Excessive nitrite in food is potentially harmful to human health because of its carcinogenic effects caused by nitroso-dervivatives. Douchi, which widely distributed throughout the country, is a traditional solid fermented soybean food with low nitrite content. In this study, bacterias which can degrade nitrite were isolated from Douchi and identified according to 16S rDNA sequence. Acinetobacter guillouiae, Acinetobacter bereziniae, Bacillus subtilis, Bacillus tequilensis, Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus aryabhattai and Bacillus methylotrophicus were selected. It was shown that all strains have nitrite degradation capability, in which 99.41 % nitrite can be degraded by Bacillus subtilis NDS1. The enzyme activities of these strains were determined at 24 h and 48 h, which corresponded to their nitrite degradation rates. The strains were firstly tried to inoculate in Jiangshui, which is a kind of traditional fermented vegetable in northwest China and often has high nitrite content. It was found that Bacillus subtilis NDS1, Bacillus tequilensis NDS3, Acinetobacter bereziniae NDS4, Bacillus subtilis NDS6, Bacillus subtilis NDS12 can degrade nitrite in Jiangshui more quickly, among which Acinetobacter bereziniae NDS4 degraded almost all nitrite in 48 h while it took 180 h for control. These results indicated that the selected strains have potential to become nitrite degradition agent in food. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  17. Advanced Oxidation: Oxalate Decomposition Testing With Ozone

    International Nuclear Information System (INIS)

    Ketusky, E.; Subramanian, K.

    2012-01-01

    At the Savannah River Site (SRS), oxalic acid is currently considered the preferred agent for chemically cleaning the large underground Liquid Radioactive Waste Tanks. It is applied only in the final stages of emptying a tank when generally less than 5,000 kg of waste solids remain, and slurrying based removal methods are no-longer effective. The use of oxalic acid is preferred because of its combined dissolution and chelating properties, as well as the fact that corrosion to the carbon steel tank walls can be controlled. Although oxalic acid is the preferred agent, there are significant potential downstream impacts. Impacts include: (1) Degraded evaporator operation; (2) Resultant oxalate precipitates taking away critically needed operating volume; and (3) Eventual creation of significant volumes of additional feed to salt processing. As an alternative to dealing with the downstream impacts, oxalate decomposition using variations of ozone based Advanced Oxidation Process (AOP) were investigated. In general AOPs use ozone or peroxide and a catalyst to create hydroxyl radicals. Hydroxyl radicals have among the highest oxidation potentials, and are commonly used to decompose organics. Although oxalate is considered among the most difficult organic to decompose, the ability of hydroxyl radicals to decompose oxalate is considered to be well demonstrated. In addition, as AOPs are considered to be 'green' their use enables any net chemical additions to the waste to be minimized. In order to test the ability to decompose the oxalate and determine the decomposition rates, a test rig was designed, where 10 vol% ozone would be educted into a spent oxalic acid decomposition loop, with the loop maintained at 70 C and recirculated at 40L/min. Each of the spent oxalic acid streams would be created from three oxalic acid strikes of an F-area simulant (i.e., Purex = high Fe/Al concentration) and H-area simulant (i.e., H area modified Purex = high Al/Fe concentration) after nearing

  18. ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E.; Subramanian, K.

    2012-02-29

    At the Savannah River Site (SRS), oxalic acid is currently considered the preferred agent for chemically cleaning the large underground Liquid Radioactive Waste Tanks. It is applied only in the final stages of emptying a tank when generally less than 5,000 kg of waste solids remain, and slurrying based removal methods are no-longer effective. The use of oxalic acid is preferred because of its combined dissolution and chelating properties, as well as the fact that corrosion to the carbon steel tank walls can be controlled. Although oxalic acid is the preferred agent, there are significant potential downstream impacts. Impacts include: (1) Degraded evaporator operation; (2) Resultant oxalate precipitates taking away critically needed operating volume; and (3) Eventual creation of significant volumes of additional feed to salt processing. As an alternative to dealing with the downstream impacts, oxalate decomposition using variations of ozone based Advanced Oxidation Process (AOP) were investigated. In general AOPs use ozone or peroxide and a catalyst to create hydroxyl radicals. Hydroxyl radicals have among the highest oxidation potentials, and are commonly used to decompose organics. Although oxalate is considered among the most difficult organic to decompose, the ability of hydroxyl radicals to decompose oxalate is considered to be well demonstrated. In addition, as AOPs are considered to be 'green' their use enables any net chemical additions to the waste to be minimized. In order to test the ability to decompose the oxalate and determine the decomposition rates, a test rig was designed, where 10 vol% ozone would be educted into a spent oxalic acid decomposition loop, with the loop maintained at 70 C and recirculated at 40L/min. Each of the spent oxalic acid streams would be created from three oxalic acid strikes of an F-area simulant (i.e., Purex = high Fe/Al concentration) and H-area simulant (i.e., H area modified Purex = high Al/Fe concentration

  19. Highly improved electrocatalytic behavior of sulfite at carbon ionic liquid electrode: Application to the analysis of some real samples

    International Nuclear Information System (INIS)

    Safavi, Afsaneh; Maleki, Norouz; Momeni, Safieh; Tajabadi, Fariba

    2008-01-01

    The electrocatalytic oxidation of sulfite was investigated at carbon ionic liquid electrode (CILE). This electrode is a very good alternative to previously described electrodes because the electrocatalytic effect is achieved without any electrode modification. Comparative experiments were carried out using carbon paste electrode (CPE) and glassy carbon electrode (GCE). At CILE, highly reproducible and well-defined cyclic voltammograms were obtained for sulfite with a peak potential of 0.55 V vs. Ag/AgCl. Sulfite oxidation at CILE does not result in deactivation of the electrode surface. The kinetic parameters for this irreversible heterogeneous electron transfer process were determined. Under optimal experimental conditions, the peak current response increased linearly with sulfite concentration over the range of 6-1000 μM. The detection limit of the method was 4 μM. The method was applied to the determination of sulfite in mineral water, grape juice and non-alcoholic beer samples

  20. Intramuscular Cobinamide Sulfite in a Rabbit Model of Sub-Lethal Cyanide Toxicity

    Science.gov (United States)

    Brenner, Matthew; Kim, Jae G.; Mahon, Sari B.; Lee, Jangwoen; Kreuter, Kelly A.; Blackledge, William; Mukai, David; Patterson, Steve; Mohammad, Othman; Sharma, Vijay S.; Boss, Gerry R.

    2009-01-01

    Objective To determine the ability of an intramuscular cobinamide sulfite injection to rapidly reverse the physiologic effects of cyanide toxicity. Background Exposure to cyanide in fires and industrial exposures and intentional cyanide poisoning by terrorists leading to mass casualties is an ongoing threat. Current treatments for cyanide poisoning must be administered intravenously, and no rapid treatment methods are available for mass casualty cyanide exposures. Cobinamide is a cobalamin (vitamin B12) analog with an extraordinarily high affinity for cyanide that is more water-soluble than cobalamin. We investigated the use of intramuscular cobinamide sulfite to reverse cyanide toxicity induced physiologic changes in a sublethal cyanide exposure animal model. Methods New Zealand white rabbits were given 10 mg sodium cyanide intravenously over 60 minutes. Quantitative diffuse optical spectroscopy and continuous wave near infrared spectroscopy monitoring of tissue oxy- and deoxyhemoglobin concentrations were performed concurrently with blood cyanide level measurements and cobinamide levels. Immediately after completion of the cyanide infusion, the rabbits were injected intramuscularly with cobinamide sulfite (n=6) or inactive vehicle (controls, n=5). Results Intramuscular administration led to rapid mobilization of cobinamide and was extremely effective at reversing the physiologic effects of cyanide on oxyhemoglobin and deoxyhemoglobin extraction. Recovery time to 63% of their baseline values in the central nervous system was in a mean of 1032 minutes in the control group and 9 minutes in the cobinamide group with a difference of 1023 minutes (95% confidence interval [CI] 116, 1874 minutes). In muscle tissue, recovery times were 76 and 24 minutes with a difference of 52 minutes (95% CI 7, 98min). Red blood cell cyanide levels returned towards normal significantly faster in cobinamide sulfite-treated animals than in control animals. Conclusions Intramuscular

  1. 3.2.1. Synthesis, crystal and molecular structure of catena-(bis(µ1-oxalic acid-µ3-hydrogen oxalate-di-aqua-sodium(I.

    Directory of Open Access Journals (Sweden)

    Olga Kovalchukova*, Sergey Aldoshin, Andrey Utenyshev, Konstantin Bogenko, Valeriy Tkachev

    2015-07-01

    Full Text Available The crystal and molecular structure of catena-(bis(µ- oxalic acid-µ-hydrogen oxalate-di-aqua-sodium(I was detected by X-Ray analysis. The compound crystallizes in the triclinic space group P-1, with a(Å 6.2378(12; b(Å 7,1115(14; c(Å 10.489(2; α(° 94.65(3; β(° 100.12(3; γ(° 97.78(3. The sodium cation in the title compound is eight coordinated and forms a square antiprism. It is surrounded by two molecules of oxalic acid, one hydrogen oxalate anion and one water molecule. Both oxalic acid and hydrogen oxalate anion act as polydentate bridging ligands. Centrosymmetric sodium cations are bounded by hydrogen oxalate anions through a system of H bonds involving the molecules of oxalic acid. In the lattice, the 3D structure stabilized by H bonds is formed.

  2. Direct transformation of calcium sulfite to {alpha}-calcium sulfate hemihydrate in a concentrated Ca-Mg-Mn chloride solution under atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Baohong Guan; Hailu Fu; Jie Yu; Guangming Jiang; Bao Kong; Zhongbiao Wu [Zhejiang University, Hangzhou (China). Department of Environmental Engineering

    2011-01-15

    Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber sludge have been generated by coal burning power plants. Utilization of the sulfite-rich sludge for preparing {alpha}-calcium sulfate hemihydrate ({alpha}-HH), an important kind of cementitious material, is of particular interest to electric utilities and environmental preservation. In the experiment, calcium sulfite hemihydrate was directly transformed to {alpha}-HH without the occurrence of calcium sulfate dihydrate (DH). The transformation was performed in a concentrated CaCl{sub 2} solution containing Mg{sup 2+} and Mn{sup 2+} at 95{sup o}C, atmospheric pressure and low pH. The oxidation of calcium sulfite and the subsequent crystallization of {alpha}-HH constitute the whole conversion, during which the oxidation turns out to be the rate controlling step. Solid solution comprised of calcium sulfite hemihydrate and calcium sulfate was found to coexist with {alpha}-HH in the suspension. Calcium sulfate increases and calcium sulfite decreases spontaneously until the solid solution disappears. Thus, it is a potential alternative to utilize sulfite-rich FGD scrubber sludge for the direct preparation of {alpha}-HH. 36 refs., 10 figs., 1 tab.

  3. Simple flow injection for determination of sulfite by amperometric detection using glassy carbon electrode modified with carbon nanotubes-PDDA-gold nanoparticles.

    Science.gov (United States)

    Amatatongchai, Maliwan; Sroysee, Wongduan; Chairam, Sanoe; Nacapricha, Duangjai

    2015-02-01

    A new approach is presented for sensitive and selective measurement of sulfite (SO3(2-)) in beverages based on a simple flow injection system with amperometric detection. In this work, the sulfite sensor was a glassy carbon electrode modified with multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-gold nanoparticles composites (CNTs-PDDA-AuNPs/GC). Electrochemical oxidation of sulfite with this electrode was first studied in 0.1M phosphate buffer (pH 7.0) using cyclic voltammetry. The results indicated that the CNTs-PDDA-AuNPs/GC electrode possesses electrocatalytic activity for the oxidation of sulfite with high sensitivity and selectivity. Sulfite was quantified using amperometric measurement with the new sensor at +0.4V vs Ag/AgCl in conjunction with flow injection. The linear working range for the quantitation of sulfite was 2-200 mg L(-1) (r(2)=0.998) with a detection limit of 0.03 mg L(-1) (3σ of blank) and an estimated precision of 1.5%.The proposed method was successfully applied to the determination of sulfite in fruit juices and wines with a sample throughput of 23 samples per hour. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Some aspects of sulphite metabolism in plants; Quelques aspects du metabolisme du sulfite chez les vegetaux

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Milan, Hernan

    1958-05-15

    As sulphite appears to be an intermediate substance in the degradation of sulphur-containing amino acids, and has an important metabolic role, notably for plants, this research thesis aims at comparing transformations which may occur for a same chemical compound (the sulphite) in various organisms belonging to different species or kingdoms. More particularly, the author studied the formation of sulphite in vegetal tissues, and the oxidisation of sulphite into sulfate within these tissues. In vitro experiments have been performed with oat, while in vivo experiments have been performed on tobacco plants [French] Le sulfite apparait comme une substance intermediaire de la degradation des acides amines soufres. Son role dans la biosynthese de certains d'entre eux, problematique chez les mammiferes, est certain chez les oiseaux, qui, a cet egard, se comportent comme des autotrophes partiels, puisqu'ils reduisent le sulfate en sulfite. On s'apercoit ainsi qu'un degre d'evolution moindre confere au sulfite une importance metabolique plus grande. On peut s'attendre a trouver chez les vegetaux un role encore accru pour le sulfite. Le present travail entre dans ce cadre d'etudes comparees des transformations que peut subir un meme type de compose chimique: le sulfite, dans divers organismes appartenant a des especes ou a des regnes differents. Les donnees acquises exposees ici auront trait aux deux points suivants: I - La formation du sulfite dans les tissus vegetaux, II - L'oxydation dans ces tissus, du sulfite en sulfate. L'avoine nous a servi comme materiel de depart pour les experiences faites in vitro. Cette plante presente en effet l'avantage de se bien cultiver en toutes saisons, de se broyer facilement, et d'etre depourvue au maximum de mucilages, de resines, substances genantes pour l'analyse ulterieure. Les essais faits in vivo, ont mis en oeuvre des plants de tabac, qui permettent une nutrition par le petiole ou par la tige particulierement aisee.

  5. Total and soluble oxalate content of some Indian spices.

    Science.gov (United States)

    Ghosh Das, Sumana; Savage, G P

    2012-06-01

    Spices, such as cinnamon, cloves, cardamom, garlic, ginger, cumin, coriander and turmeric are used all over the world as flavouring and colouring ingredients in Indian foods. Previous studies have shown that spices contain variable amounts of total oxalates but there are few reports of soluble oxalate contents. In this study, the total, soluble and insoluble oxalate contents of ten different spices commonly used in Indian cuisine were measured. Total oxalate content ranged from 194 (nutmeg) to 4,014 (green cardamom) mg/100 g DM, while the soluble oxalate contents ranged from 41 (nutmeg) to 3,977 (green cardamom) mg/100 g DM. Overall, the percentage of soluble oxalate content of the spices ranged from 4.7 to 99.1% of the total oxalate content which suggests that some spices present no risk to people liable to kidney stone formation, while other spices can supply significant amounts of soluble oxalates and therefore should be used in moderation.

  6. Studies in the solubility of Pu(III) oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Hasilkar, S P; Khedekar, N B; Chander, K; Jadhav, V; Jain, H C [Bhabha Atomic Research Centre, Bombay (India). Fuel Reprocessing Div.

    1994-11-01

    Studies have been carried out on the solubility of Pu(III) oxalate by precipitation of Pu(III) oxalate from varying concentrations of HNO[sub 3]/HCl (0.5-2.0M) solutions and also by equilibrating freshly prepared Pu(III) oxalate with solutions containing varying concentrations of HNO[sub 3]/HCl, oxalic acid and ascorbic acid. Pu(III) solutions in HNO[sub 3] and HCl media were prepared by reduction of Pu(IV) with ascorbic acid. 0.01-0.10M ascorbic acid concentration in the aqueous solution was maintained as holding reductant. The solubility of Pu(III) oxalate was found to be a minimum in 0.5M-1M HNO[sub 3]/HCl solutions containing 0.05M ascorbic acid and 0.2M excess oxalic acid in the supernatant. (author) 6 refs.; 6 tabs.

  7. Atmospheric production of oxalic acid/oxalate and nitric acid/nitrate in the Tampa Bay airshed: Parallel pathways

    Science.gov (United States)

    Martinelango, P. Kalyani; Dasgupta, Purnendu K.; Al-Horr, Rida S.

    Oxalic acid is the dominant dicarboxylic acid (DCA), and it constitutes up to 50% of total atmospheric DCAs, especially in non-urban and marine atmospheres. A significant amount of particulate H 2Ox/oxalate (Ox) occurred in the coarse particle fraction of a dichotomous sampler, the ratio of oxalate concentrations in the PM 10 to PM 2.5 fractions ranged from 1 to 2, with mean±sd being 1.4±0.2. These results suggest that oxalate does not solely originate in the gas phase and condense into particles. Gaseous H 2Ox concentrations are much lower than particulate Ox concentrations and are well correlated with HNO 3, HCHO, and O 3, supporting a photochemical origin. Of special relevance to the Bay Region Atmospheric Chemistry Experiment (BRACE) is the extent of nitrogen deposition in the Tampa Bay estuary. Hydroxyl radical is primarily responsible for the conversion of NO 2 to HNO 3, the latter being much more easily deposited. Hydroxyl radical is also responsible for the aqueous phase formation of oxalic acid from alkenes. Hence, we propose that an estimate of rad OH can be obtained from H 2Ox/Ox production rate and we accordingly show that the product of total oxalate concentration and NO 2 concentration approximately predicts the total nitrate concentration during the same period.

  8. Pseudomonas fluorescens ATCC 13525 Containing an Artificial Oxalate Operon and Vitreoscilla Hemoglobin Secretes Oxalic Acid and Solubilizes Rock Phosphate in Acidic Alfisols

    Science.gov (United States)

    Archana, G.; Naresh Kumar, G.

    2014-01-01

    Oxalate secretion was achieved in Pseudomonas fluorescens ATCC 13525 by incorporation of genes encoding Aspergillus niger oxaloacetate acetyl hydrolase (oah), Fomitopsis plaustris oxalate transporter (FpOAR) and Vitreoscilla hemoglobin (vgb) in various combinations. Pf (pKCN2) transformant containing oah alone accumulated 19 mM oxalic acid intracellularly but secreted 1.2 mM. However, in the presence of an artificial oxalate operon containing oah and FpOAR genes in plasmid pKCN4, Pf (pKCN4) secreted 13.6 mM oxalate in the medium while 3.6 mM remained inside. This transformant solubilized 509 μM of phosphorus from rock phosphate in alfisol which is 4.5 fold higher than the Pf (pKCN2) transformant. Genomic integrants of P. fluorescens (Pf int1 and Pf int2) containing artificial oxalate operon (plac-FpOAR-oah) and artificial oxalate gene cluster (plac-FpOAR-oah, vgb, egfp) secreted 4.8 mM and 5.4 mM oxalic acid, released 329 μM and 351 μM P, respectively, in alfisol. The integrants showed enhanced root colonization, improved growth and increased P content of Vigna radiata plants. This study demonstrates oxalic acid secretion in P. fluorescens by incorporation of an artificial operon constituted of genes for oxalate synthesis and transport, which imparts mineral phosphate solubilizing ability to the organism leading to enhanced growth and P content of V. radiata in alfisol soil. PMID:24705024

  9. Pseudomonas fluorescens ATCC 13525 containing an artificial oxalate operon and Vitreoscilla hemoglobin secretes oxalic acid and solubilizes rock phosphate in acidic alfisols.

    Directory of Open Access Journals (Sweden)

    Kavita Yadav

    Full Text Available Oxalate secretion was achieved in Pseudomonas fluorescens ATCC 13525 by incorporation of genes encoding Aspergillus niger oxaloacetate acetyl hydrolase (oah, Fomitopsis plaustris oxalate transporter (FpOAR and Vitreoscilla hemoglobin (vgb in various combinations. Pf (pKCN2 transformant containing oah alone accumulated 19 mM oxalic acid intracellularly but secreted 1.2 mM. However, in the presence of an artificial oxalate operon containing oah and FpOAR genes in plasmid pKCN4, Pf (pKCN4 secreted 13.6 mM oxalate in the medium while 3.6 mM remained inside. This transformant solubilized 509 μM of phosphorus from rock phosphate in alfisol which is 4.5 fold higher than the Pf (pKCN2 transformant. Genomic integrants of P. fluorescens (Pf int1 and Pf int2 containing artificial oxalate operon (plac-FpOAR-oah and artificial oxalate gene cluster (plac-FpOAR-oah, vgb, egfp secreted 4.8 mM and 5.4 mM oxalic acid, released 329 μM and 351 μM P, respectively, in alfisol. The integrants showed enhanced root colonization, improved growth and increased P content of Vigna radiata plants. This study demonstrates oxalic acid secretion in P. fluorescens by incorporation of an artificial operon constituted of genes for oxalate synthesis and transport, which imparts mineral phosphate solubilizing ability to the organism leading to enhanced growth and P content of V. radiata in alfisol soil.

  10. Effect of sulfite and fluoride on carbon dioxide uptake by mosses in the light

    Energy Technology Data Exchange (ETDEWEB)

    Inglis, F.; Hill, D.J.

    1974-01-01

    Four mosses, Bryum argenteum, Grimmia pulvinata, Hypnum cupressiforme and Tortula muralis were exposed to sulfite, and their uptake of radioactive bicarbonate measured. About 50% reduction in /sup 14/C uptake was caused by 0.01-0.1 mM sulfite. The effect of pH indicated that SO/sub 2/ (or H/sub 2/SO/sub 3/) was the active molecular species. Fluoride had little effect on /sup 14/C uptake.

  11. The roles of polycarboxylates in Cr(VI)/sulfite reaction system: Involvement of reactive oxygen species and intramolecular electron transfer

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Bo, E-mail: bjiang86upc@163.com [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong (China); School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033 (China); Wang, Xianli; Liu, Yukun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong (China); Wang, Zhaohui [College of Environmental Science and Engineering, Donghua University, Shanghai 201620 (China); Southern Cross GeoScience, Southern Cross University, Lismore, NSW 2480 (Australia); Zheng, Jingtang, E-mail: jtzheng03@163.com [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong (China); Wu, Mingbo, E-mail: wumb@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, Shandong (China)

    2016-03-05

    Highlights: • The formations of SO{sub 4}·{sup −} and OH·, involve in Cr(VI) reduction induced by S(IV). • Affinity of polycarboxylate to Cr(VI) accelerates Cr(VI) reduction rate. • Polycarboxylates can act as electron donors for Cr(VI) reduction retrenching S(IV). • Only oxalate can enhance the formations of SO{sub 4}·{sup −} and OH· in Cr(VI)/S(IV) system. - Abstract: In this study, the effects of polycarboxylates on both Cr(VI) reduction and S(IV) consumption in Cr(VI)/S(IV) system was investigated in acidic solution. Under aerobic condition, the productions of reactive oxygen species (ROS), i.e., SO{sub 4}·{sup −} and OH·, have been confirmed in S(IV) reducing Cr(VI) process by using electron spin resonance and fluorescence spectrum techniques, leading to the excess consumption of S(IV). However, when polycarboxylates (oxalic, citric, malic and tartaric acid) were present in Cr(VI)/S(IV) system, the affinity of polycarboxylates to CrSO{sub 6}{sup 2−} can greatly promote the reduction of Cr(VI) via expanding the coordination of Cr(VI) species from tetrahedron to hexahedron. Besides, as alternatives to S(IV), these polycarboxylates can also act as electron donors for Cr(VI) reduction via intramolecular electron transfer reaction, which is dependent on the energies of the highest occupied molecular orbital of these polycarboxylates. Notably, the variant electron donating capacity of these polycarboxylates resulted in different yield of ROS and therefore the oxidation efficiencies of other pollutants, e.g., rhodamine B and As(III). Generally, this study does not only shed light on the mechanism of S(IV) reducing Cr(VI) process mediated by polycarboxylates, but also provides an escalated, cost-effective and green strategy for the remediation of Cr(VI) using sulfite as a reductant.

  12. Time-dependent depletion of nitrite in pork/beef and chicken meat products and its effect on nitrite intake estimation

    Science.gov (United States)

    Merino, Leonardo; Darnerud, Per Ola; Toldrá, Fidel; Ilbäck, Nils-Gunnar

    2016-01-01

    ABSTRACT The food additive nitrite (E249, E250) is commonly used in meat curing as a food preservation method. Because of potential negative health effects of nitrite, its use is strictly regulated. In an earlier study we have shown that the calculated intake of nitrite in children can exceed the acceptable daily intake (ADI) when conversion from dietary nitrate to nitrite is included. This study examined time-dependent changes in nitrite levels in four Swedish meat products frequently eaten by children: pork/beef sausage, liver paté and two types of chicken sausage, and how the production process, storage and also boiling (e.g., simmering in salted water) and frying affect the initial added nitrite level. The results showed a steep decrease in nitrite level between the point of addition to the product and the first sampling of the product 24 h later. After this time, residual nitrite levels continued to decrease, but much more slowly, until the recommended use-by date. Interestingly, this continuing decrease in nitrite was much smaller in the chicken products than in the pork/beef products. In a pilot study on pork/beef sausage, we found no effects of boiling on residual nitrite levels, but frying decreased nitrite levels by 50%. In scenarios of time-dependent depletion of nitrite using the data obtained for sausages to represent all cured meat products and including conversion from dietary nitrate, calculated nitrite intake in 4-year-old children generally exceeded the ADI. Moreover, the actual intake of nitrite from cured meat is dependent on the type of meat source, with a higher residual nitrite levels in chicken products compared with pork/beef products. This may result in increased nitrite exposure among consumers shifting their consumption pattern of processed meats from red to white meat products. PMID:26743589

  13. Chemical composition and utilization of Hungarian spent sulfite liquor

    Energy Technology Data Exchange (ETDEWEB)

    Toth, B

    1968-01-01

    A review on the composition of Hungarian spent sulfite liquor and on its possible utilization, e.g., for the manufacturing of vanillin, yeast protein, or ethanol, as well as its direct utilization as a plasticizer for cement, additive for insecticides, or in adhesives.

  14. Oxalic acid decreases calcium absorption in rats

    International Nuclear Information System (INIS)

    Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.

    1987-01-01

    Calcium absorption from salts and foods intrinsically labeled with 45 Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO 3 and CaCl 2 than from CaC 2 O 4 (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach

  15. Synthesis and structural characterization of actinide oxalate compounds

    International Nuclear Information System (INIS)

    Tamain, C.

    2011-01-01

    Oxalic acid is a well-known reagent to recover actinides thanks to the very low solubility of An(IV) and An(III) oxalate compounds in acidic solution. Therefore, considering mixed-oxide fuel or considering minor actinides incorporation in ceramic fuel materials for transmutation, oxalic co-conversion is convenient to synthesize mixed oxalate compounds, precursors of oxide solid solutions. As the existing oxalate single crystal syntheses are not adaptable to the actinide-oxalate chemistry or to their manipulation constrains in gloves box, several original crystal growth methods were developed. They were first validate and optimized on lanthanides and uranium before the application to transuranium elements. The advanced investigations allow to better understand the syntheses and to define optimized chemical conditions to promote crystal growth. These new crystal growth methods were then applied to a large number of mixed An1(IV)-An2(III) or An1(IV)-An2(IV) systems and lead to the formation of the first original mixed An1(IV)-An2(III) and An1(IV)-An2(IV) oxalate single crystals. Finally thanks to the first thorough structural characterizations of these compounds, single crystal X-ray diffraction, EXAFS or micro-RAMAN, the particularly weak oxalate-actinide compounds structural database is enriched, which is essential for future studied nuclear fuel cycles. (author) [fr

  16. Oxalate Content of Taro Leaves Grown in Central Vietnam

    Science.gov (United States)

    Du Thanh, Hang; Phan Vu, Hai; Vu Van, Hai; Le Duc, Ngoan; Le Minh, Tuan; Savage, Geoffrey

    2017-01-01

    Leaves were harvested from four different cultivars of Colocasia esculenta and three cultivars of Alocasia odora that were growing on nine different farms in central Vietnam. The total, soluble and insoluble oxalate contents of the leaves were extracted and measured using HPLC chromatography. Total calcium determinations were also carried out on the same samples. The total oxalate content of the leaves ranged from 433.8 to 856.1 mg/100 g wet matter (WM) while the soluble oxalate ranged from 147.8 to 339.7 mg/100 g WM. The proportion of soluble oxalate ranged from 28% to 41% (overall mean 35%) of the total oxalate content of the leaves. The equivalent insoluble oxalate proportion ranged from 59% to 72% of the total (overall mean 65%). There was little difference between the Colocasia esculenta and Alocasia odora taro cultivars, although the total oxalate content was significantly higher in Alocasia odora cultivars. The overall mean total calcium content was 279.5 mg/100 WM and the percentage of insoluble calcium bound as calcium oxalate ranged from 31.7% to 57.3% of the total calcium content (overall mean 47.1%). The oxalate content in taro leaves is a major factor to consider when different cultivars of taro are recommended for human or animal consumption. PMID:28231080

  17. Short communication: Urinary oxalate and calcium excretion by dogs and cats diagnosed with calcium oxalate urolithiasis

    NARCIS (Netherlands)

    Dijcker, J.C.; Kummeling, A.; Hagen-Plantinga, E.A.; Hendriks, W.H.

    2012-01-01

    Introduction Urine concentrations of oxalate and calcium play an important role in calcium oxalate (CaOx) urolith formation in dogs and cats, with high excretions of both substances increasing the chance of CaOx urolithiasis. In 17 CaOx-forming dogs, urine calcium:creatinine ratio (Ca:Cr) was found

  18. Oxalate quantification in hemodialysate to assess dialysis adequacy for primary hyperoxaluria.

    Science.gov (United States)

    Tang, Xiaojing; Voskoboev, Nikolay V; Wannarka, Stacie L; Olson, Julie B; Milliner, Dawn S; Lieske, John C

    2014-01-01

    Patients with primary hyperoxaluria (PH) overproduce oxalate which is eliminated via the kidneys. If end-stage kidney disease develops they are at high risk for systemic oxalosis, unless adequate oxalate is removed during hemodialysis (HD) to equal or exceed ongoing oxalate production. The purpose of this study was to validate a method to measure oxalate removal in this unique group of dialysis patients. Fourteen stable patients with a confirmed diagnosis of PH on HD were included in the study. Oxalate was measured serially in hemodialysate and plasma samples in order to calculate rates of oxalate removal. HD regimens were adjusted according to a given patient's historical oxalate production, amount of oxalate removal at dialysis, residual renal clearance of oxalate, and plasma oxalate levels. After a typical session of HD, plasma oxalate was reduced by 78.4 ± 7.7%. Eight patients performed HD 6 times/week, 2 patients 5 times/week, and 3 patients 3 times/week. Combined oxalate removal by HD and the kidneys was sufficient to match or exceed endogenous oxalate production. After a median period of 9 months, pre-dialysis plasma oxalate was significantly lower than initially (75.1 ± 33.4 vs. 54.8 ± 46.6 mmol/l, p = 0.02). This methodology can be used to individualize the dialysis prescription of PH patients to prevent oxalosis during the time they are maintained on HD and to reduce risk of oxalate injury to a transplanted kidney.

  19. Acute oxalate nephropathy caused by ethylene glycol poisoning

    Directory of Open Access Journals (Sweden)

    Jung Woong Seo

    2012-12-01

    Full Text Available Ethylene glycol (EG is a sweet-tasting, odorless organic solvent found in many agents, such as anti-freeze. EG is composed of four organic acids: glycoaldehyde, glycolic acid, glyoxylic acid and oxalic acid in vivo. These metabolites are cellular toxins that can cause cardio-pulmonary failure, life-threatening metabolic acidosis, central nervous system depression, and kidney injury. Oxalic acid is the end product of EG, which can precipitate to crystals of calcium oxalate monohydrate in the tubular lumen and has been linked to acute kidney injury. We report a case of EG-induced oxalate nephropathy, with the diagnosis confirmed by kidney biopsy, which showed acute tubular injury of the kidneys with extensive intracellular and intraluminal calcium oxalate monohydrate crystal depositions.

  20. Oxalate Content of the Herb Good-King-Henry, Blitum Bonus-Henricus

    Directory of Open Access Journals (Sweden)

    Wanying Li

    2015-05-01

    Full Text Available The total, soluble and insoluble oxalate contents of the leaves, stems and buds of Good-King-Henry (Blitum Bonus-Henricus were extracted and measured using HPLC chromatography. The large, mature leaves contained 42% more total oxalate than in the small leaves and the soluble oxalate content of the large leaves was 33% higher than the smaller leaves. Cooking the mixed leaves, stems and buds in boiling water for two minutes significantly (p < 0.05 reduced the total oxalate when compared to the raw plant parts. Pesto sauce made from mixed leaves contained 257 mg total oxalate/100 g fresh weight; this was largely made up of insoluble oxalates (85% of the total oxalate content. Soup made from mixed leaves contained lower levels of total oxalates (44.26 ± 0.49 mg total oxalate/100 g fresh weight and insoluble oxalate made up 49% of the oxalate contents. The levels of oxalates in the Good-King-Henry leaves were high, suggesting that the leaves should be consumed occasionally as a delicacy because of their unique taste rather than as a significant part of the diet. However, the products made from Good-King-Henry leaves indicated that larger amounts could be consumed as the oxalate levels were reduced by dilution and processing.

  1. Kinetics and mechanism of oxidation of super-reduced cobalamin and cobinamide species by thiosulfate, sulfite and dithionite.

    Science.gov (United States)

    Dereven'kov, Ilia A; Salnikov, Denis S; Makarov, Sergei V; Boss, Gerry R; Koifman, Oskar I

    2013-11-21

    We studied the kinetics of reactions of cob(I)alamin and cob(I)inamide with thiosulfate, sulfite, and dithionite by UV-Visible (UV-Vis) and stopped-flow spectroscopy. We found that the two Co(I) species were oxidized by these sulfur-containing compounds to Co(II) forms: oxidation by excess thiosulfate leads to penta-coordinate complexes and oxidation by excess sulfite or dithionite leads to hexa-coordinate Co(II)-SO2(-) complexes. The net scheme involves transfer of three electrons in the case of oxidation by thiosulfate and one electron for oxidation by sulfite and dithionite. On the basis of kinetic data, the nature of the reactive oxidants was suggested, i.e., HS2O3(-) (for oxidation by thiosulfate), S2O5(2-), HSO3(-), and aquated SO2 (for oxidation by sulfite), and S2O4(2-) and SO2(-) (for oxidation by dithionite). No difference was observed in kinetics with cob(i)alamin or cob(i)inamide as reductants.

  2. Comparison of Oxidation Kinetics of Nitrite-Oxidizing Bacteria: Nitrite Availability as a Key Factor in Niche Differentiation

    Science.gov (United States)

    Nowka, Boris; Daims, Holger

    2014-01-01

    Nitrification has an immense impact on nitrogen cycling in natural ecosystems and in wastewater treatment plants. Mathematical models function as tools to capture the complexity of these biological systems, but kinetic parameters especially of nitrite-oxidizing bacteria (NOB) are lacking because of a limited number of pure cultures until recently. In this study, we compared the nitrite oxidation kinetics of six pure cultures and one enrichment culture representing three genera of NOB (Nitrobacter, Nitrospira, Nitrotoga). With half-saturation constants (Km) between 9 and 27 μM nitrite, Nitrospira bacteria are adapted to live under significant substrate limitation. Nitrobacter showed a wide range of lower substrate affinities, with Km values between 49 and 544 μM nitrite. However, the advantage of Nitrobacter emerged under excess nitrite supply, sustaining high maximum specific activities (Vmax) of 64 to 164 μmol nitrite/mg protein/h, contrary to the lower activities of Nitrospira of 18 to 48 μmol nitrite/mg protein/h. The Vmax (26 μmol nitrite/mg protein/h) and Km (58 μM nitrite) of “Candidatus Nitrotoga arctica” measured at a low temperature of 17°C suggest that Nitrotoga can advantageously compete with other NOB, especially in cold habitats. The kinetic parameters determined represent improved basis values for nitrifying models and will support predictions of community structure and nitrification rates in natural and engineered ecosystems. PMID:25398863

  3. Oxalate Content of Taro Leaves Grown in Central Vietnam

    Directory of Open Access Journals (Sweden)

    Hang Du Thanh

    2017-01-01

    Full Text Available Leaves were harvested from four different cultivars of Colocasia esculenta and three cultivars of Alocasia odora that were growing on nine different farms in central Vietnam. The total, soluble and insoluble oxalate contents of the leaves were extracted and measured using HPLC chromatography. Total calcium determinations were also carried out on the same samples. The total oxalate content of the leaves ranged from 433.8 to 856.1 mg/100 g wet matter (WM while the soluble oxalate ranged from 147.8 to 339.7 mg/100 g WM. The proportion of soluble oxalate ranged from 28% to 41% (overall mean 35% of the total oxalate content of the leaves. The equivalent insoluble oxalate proportion ranged from 59% to 72% of the total (overall mean 65%. There was little difference between the Colocasia esculenta and Alocasia odora taro cultivars, although the total oxalate content was significantly higher in Alocasia odora cultivars. The overall mean total calcium content was 279.5 mg/100 WM and the percentage of insoluble calcium bound as calcium oxalate ranged from 31.7% to 57.3% of the total calcium content (overall mean 47.1%. The oxalate content in taro leaves is a major factor to consider when different cultivars of taro are recommended for human or animal consumption.

  4. Urinary oxalate to creatinine ratios in healthy Turkish schoolchildren.

    Science.gov (United States)

    Dursun, Ismail; Çelik, İlknur; Poyrazoglu, Hakan M; Köse, Kader; Tanrıkulu, Esen; Sahin, Habibe; Yılmaz, Kenan; Öztürk, Ahmet; Yel, Sibel; Gündüz, Zübeyde; Düşünsel, Ruhan

    2017-11-01

    we aimed to establish reference values for urinary oxalate to creatinine ratios in healthy children aged 6-15 years and to investigate the relationship between their nutritional habits and oxalate excretion. Random urine specimens from 953 healthy children aged 6-15 years were obtained and analyzed for oxalate and creatinine. Additionally, a 24-h dietary recall form was prepared and given to them. The ingredient composition of the diet was calculated. The children were divided into three groups according to age: Group I (69 years, n = 353), Group II (10-12 years, n = 335), and Group III (13-15 years, n = 265). The 95th percentile of the oxalate to creatinine ratio for subjects aged 6-9, 10-12, and 13-15 years were 0.048, 0.042, and 0.042 mg/mg, respectively. The oxalate to creatinine ratio was significantly higher in Group 1 than in Group 2 and Group 3. Urinary oxalate excretion was positively correlated with increased protein intake and negatively correlated with age. A significant positive correlation was determined between urinary oxalate excretion and the proline, serine, protein, and glycine content of diet. Dietary proline intake showed a positive correlation with the urine oxalate to creatinine ratio and was found to be an independent predictor for urinary oxalate. These data lend support to the idea that every country should have its own normal reference values to determine the underlying metabolic risk factor for kidney stone disease since regional variation in the dietary intake of proteins and other nutrients can affect normal urinary excretion of oxalate.

  5. Preparation, Characterization, and Selectivity Study of Mixed-Valence Sulfites

    Science.gov (United States)

    Silva, Luciana A.; de Andrade, Jailson B.

    2010-01-01

    A project involving the synthesis of an isomorphic double sulfite series and characterization by classical inorganic chemical analyses is described. The project is performed by upper-level undergraduate students in the laboratory. This compound series is suitable for examining several chemical concepts and analytical techniques in inorganic…

  6. Experimental Study of Leaching and Penetration of Nitrite ions in Nitrite-type Repair Materials on the Surface of Concrete

    Directory of Open Access Journals (Sweden)

    Masumi Inoue

    2017-01-01

    Full Text Available This study aimed to clarify the leaching properties of nitrite ions in nitrite-type repair materials exposed to rainfall. Repaired concrete specimens were prepared for leaching tests using a lithium nitrite solution, and the amounts of leaching and penetration of nitrite ions were measured under simulated rainfall. The results demonstrated that the amount of leaching could be controlled by using polymer cement paste and mortar surface coatings containing lithium nitrite solution, and by using polymer cement mortar surface coatings following direct lithium nitrite solution coatings. Furthermore, the amount of nitrite ion leaching in all cases was lower than the discharge standard value established by the water pollution control law.

  7. Sinorhizobium meliloti sigma factors RpoE1 and RpoE4 are activated in stationary phase in response to sulfite.

    Directory of Open Access Journals (Sweden)

    Bénédicte Bastiat

    Full Text Available Rhizobia are soil bacteria able to establish a nitrogen-fixing symbiosis with legume plants. Both in soil and in planta, rhizobia spend non-growing periods resembling the stationary phase of in vitro-cultured bacteria. The primary objective of this work was to better characterize gene regulation in this biologically relevant growth stage in Sinorhizobium meliloti. By a tap-tag/mass spectrometry approach, we identified five sigma factors co-purifying with the RNA polymerase in stationary phase: the general stress response regulator RpoE2, the heat shock sigma factor RpoH2, and three extra-cytoplasmic function sigma factors (RpoE1, RpoE3 and RpoE4 belonging to the poorly characterized ECF26 subgroup. We then showed that RpoE1 and RpoE4 i are activated upon metabolism of sulfite-generating compounds (thiosulfate and taurine, ii display overlapping regulatory activities, iii govern a dedicated sulfite response by controlling expression of the sulfite dehydrogenase SorT, iv are activated in stationary phase, likely as a result of endogenous sulfite generation during bacterial growth. We showed that SorT is required for optimal growth of S. meliloti in the presence of sulfite, suggesting that the response governed by RpoE1 and RpoE4 may be advantageous for bacteria in stationary phase either by providing a sulfite detoxification function or by contributing to energy production through sulfite respiration. This paper therefore reports the first characterization of ECF26 sigma factors, the first description of sigma factors involved in control of sulphur metabolism, and the first indication that endogenous sulfite may act as a signal for regulation of gene expression upon entry of bacteria in stationary phase.

  8. The electrochemical oxidation of sulfite on gold: UV-Vis reflectance spectroscopy at a rotating disk electrode

    International Nuclear Information System (INIS)

    Tolmachev, Yuriy V.; Scherson, Daniel A.

    2004-01-01

    Certain aspects of the electrochemical oxidation of sulfite in buffered, mildly acidic aqueous solutions (pH 5.23) have been examined using in situ near normal incidence UV-Vis reflectance spectroscopy (NNI-UVRS) at a Au rotating disk electrode (RDE). The dependence of the limiting current, i lim , on the rotation rate of the RDE was found to display classical Levich behavior up to potentials well within the range in which Au forms a surface oxide in the neat (sulfite-free) supporting electrolyte. However, simultaneous in situ NNI-UVRS measurements performed at λ=500 nm during sulfite oxidation failed to show any evidence for the presence of oxide on the Au surface within that entire potential range. Polarization of the Au RDE at more positive potentials led to a sudden drop in i lim , ca. an order of magnitude, which correlated with an abrupt decrease in the intensity of the reflected light, consistent with formation of (one or more forms of) Au oxide on the surface. On the basis of these and other observations a model has been proposed in which sulfite reacts chemically with adsorbed oxygen on the surface (oxygen atom transfer) in the region that precedes partial inhibition. As the potential is increased, adsorbed oxygen undergoes Au-O place exchange forming two-dimensional nuclei on the surface, which undergo rapid (autocatalytic) growth, covering an area large enough to block significantly sulfite oxidation

  9. Pseudomonas fluorescens ATCC 13525 Containing an Artificial Oxalate Operon and Vitreoscilla Hemoglobin Secretes Oxalic Acid and Solubilizes Rock Phosphate in Acidic Alfisols

    OpenAIRE

    Yadav, Kavita; Kumar, Chanchal; Archana, G.; Naresh Kumar, G.

    2014-01-01

    Oxalate secretion was achieved in Pseudomonas fluorescens ATCC 13525 by incorporation of genes encoding Aspergillus niger oxaloacetate acetyl hydrolase (oah), Fomitopsis plaustris oxalate transporter (FpOAR) and Vitreoscilla hemoglobin (vgb) in various combinations. Pf (pKCN2) transformant containing oah alone accumulated 19 mM oxalic acid intracellularly but secreted 1.2 mM. However, in the presence of an artificial oxalate operon containing oah and FpOAR genes in plasmid pKCN4, Pf (pKCN4) s...

  10. Nitrite-dependent vasodilation is facilitated by hypoxia and is independent of known NO-generating nitrite reductase activities

    DEFF Research Database (Denmark)

    Fago, Angela; Dalsgaard, Thomas; Fago, Angela

    2007-01-01

    is largely intrinsic to the vessel and that under hypoxia physiological nitrite concentrations are sufficient to induce NO-mediated vasodilation independently of the nitrite reductase activities investigated here. Possible reaction mechanisms for nitrite vasoactivity, including formation of S...

  11. Chemical by-products from spent sulfite liquors

    Energy Technology Data Exchange (ETDEWEB)

    Whitmore, Jr, L M; Wiley, A J

    1958-01-01

    Current practices for recovering sugars, lignosulfonates, ethanol and feed yeast and product uses are reviewed. A process for separating sugars is described in which the sulfite liquor is spray dried and refluxed with acetone containing a concentrated H/sub 2/SO/sub 4/ catalyst, and the di-acetone sugar derivatives are filtered or centrifuged from the acetone insolubles. Recovery of guaiacyl and syringyl derivatives from the lignosulfonate portion of the liquor is discussed.

  12. Nitrite disrupts multiple physiological functions in aquatic animals

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2003-01-01

    be inhibited, while changes in ammonia and urea levels and excretion rates reflect an influence of nitrite on nitrogen metabolism. Detoxification of nitrite occurs via endogenous oxidation to nitrate, and elimination of nitrite takes place both via gills and urine. The susceptibility to nitrite varies between...... nitrite-induced vasodilation (possibly via nitric oxide generated from nitrite) that is countered by increased cardiac pumping to re-establish blood pressure. Nitrite can form and/or mimic nitric oxide and thereby interfere with processes regulated by this local hormone. Steroid hormone synthesis may...

  13. Addition of calcium compounds to reduce soluble oxalate in a high oxalate food system.

    Science.gov (United States)

    Bong, Wen-Chun; Vanhanen, Leo P; Savage, Geoffrey P

    2017-04-15

    Spinach (Spinacia oleracea L.) is often used as a base vegetable to make green juices that are promoted as healthy dietary alternatives. Spinach is known to contain significant amounts of oxalates, which are toxic and, if consumed regularly, can lead to the development of kidney stones. This research investigates adding 50-500mg increments of calcium carbonate, calcium chloride, calcium citrate and calcium sulphate to 100g of raw homogenates of spinach to determine whether calcium would combine with the soluble oxalate present in the spinach. Calcium chloride was the most effective additive while calcium carbonate was the least effective. The formation of insoluble oxalate after incubation at 25°C for 30min is a simple practical step that can be incorporated into the juicing process. This would make the juice considerably safer to consume on a regular basis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Oxidation of ammonium sulfite by a multi-needle-to-plate gas phase pulsed corona discharge reactor

    Science.gov (United States)

    Ren, Hua; Lu, Na; Shang, Kefeng; Li, Jie; Wu, Yan

    2013-03-01

    The oxidation of ammonium sulfite in the ammonia-based flue gas desulfurization (FGD) process was investigated in a multi-needle-to-plate gas phase pulsed corona discharge reactor in this paper. The effect of several parameters, including capacitance and peak pulse voltage of discharge system, electrode gap and bubbling gas flow rate on the oxidation rate of ammonium sulfite was reviewed. The oxidation rate of ammonium sulfite could reach 47.2% at the capacitance, the peak pulse voltage, electrode gap and bubbling gas flow rate equal to 2 nF, -24.6 k V, 35 mm and 4 L min-1 within treatment time of 40 min The experimental results indicate that the gas phase pulsed discharge system with a multi-needle-to-plate electrode can oxide the ammonium sulfite. The oxidation rate increased with the applied capacitance and peak pulse voltage and decreased with the electrode gap. As the bubbling gas flow rate increased, the oxidation rate increased first and then tended to reach a stationary value. These results would be important for the process optimization of the (NH4)2SO3 to (NH4)2SO4 oxidation.

  15. 4-Methoxybenzamidinium hydrogen oxalate monohydrate

    Directory of Open Access Journals (Sweden)

    Simona Irrera

    2012-12-01

    Full Text Available The title hydrated salt, C8H11N2O+·C2HO4−·H2O, was synthesized by a reaction of 4-methoxybenzamidine (4-amidinoanisole and oxalic acid in water solution. In the cation, the amidinium group forms a dihedral angle of 15.60 (6° with the mean plane of the benzene ring. In the crystal, each amidinium unit is bound to three acetate anions and one water molecule by six distinct N—H...O hydrogen bonds. The ion pairs of the asymmetric unit are joined by two N—H...O hydrogen bonds into ionic dimers in which the carbonyl O atom of the semi-oxalate anion acts as a bifurcated acceptor, thus generating an R12(6 motif. These subunits are then joined through the remaining N—H...O hydrogen bonds to adjacent semi-oxalate anions into linear tetrameric chains running approximately along the b axis. The structure is stabilized by N—H...O and O—H...O intermolecular hydrogen bonds. The water molecule plays an important role in the cohesion and the stability of the crystal structure being involved in three hydrogen bonds connecting two semi-oxalate anions as donor and a benzamidinium cation as acceptor.

  16. Determination of free sulfites (SO3-2) in dried fruits processed with sulfur dioxide by ion chromatography through anion exchange column and conductivity detection.

    Science.gov (United States)

    Liao, Benjamin S; Sram, Jacqueline C; Files, Darin J

    2013-01-01

    A simple and effective anion ion chromatography (IC) method with anion exchange column and conductivity detector has been developed to determine free sulfites (SO3-2) in dried fruits processed with sulfur dioxide. No oxidation agent, such as hydrogen peroxide, is used to convert sulfites to sulfates for IC analysis. In addition, no stabilizing agent, such as formaldehyde, fructose or EDTA, is required during the sample extraction. This method uses aqueous 0.2 N NaOH as the solvent for standard preparation and sample extraction. The sulfites, either prepared from standard sodium sulfite powder or extracted from food samples, are presumed to be unbound SO3-2 in aqueous 0.2 N NaOH (pH > 13), because the bound sulfites in the sample matrix are released at pH > 10. In this study, sulfites in the standard solutions were stable at room temperature (i.e., 15-25 degrees C) for up to 12 days. The lowest standard of the linear calibration curve is set at 1.59 microg/mL SO3-2 (equivalent to 6.36 microg/g sample with no dilution) for analysis of processed dried fruits that would contain high levels (>1000 microg/g) of sulfites. As a consequence, this method typically requires significant dilution of the sample extract. Samples are prepared with a simple procedure of sample compositing, extraction with aqueous 0.2 N NaOH, centrifugation, dilution as needed, and filtration prior to IC. The sulfites in these sample extracts are stable at room temperature for up to 20 h. Using anion IC, the sulfites are eluted under isocratic conditions with 10 mM aqueous sodium carbonate solution as the mobile phase passing through an anion exchange column. The sulfites are easily separated, with an analysis run time of 18 min, regardless of the dried fruit matrix. Recoveries from samples spiked with sodium sulfites were demonstrated to be between 81 and 105% for five different fruit matrixes (apricot, golden grape, white peach, fig, and mango). Overall, this method is simple to perform and

  17. Acute oxalate nephropathy after ingestion of star fruit.

    Science.gov (United States)

    Chen, C L; Fang, H C; Chou, K J; Wang, J S; Chung, H M

    2001-02-01

    Acute oxalate nephropathy associated with ingestion of star fruit (carambola) has not been reported before. We report the first two cases. These patients developed nausea, vomiting, abdominal pain, and backache within hours of ingesting large quantities of sour carambola juice; then acute renal failure followed. Both patients needed hemodialysis for oliguric acute renal failure, and pathologic examinations showed typical changes of acute oxalate nephropathy. The renal function recovered 4 weeks later without specific treatment. Sour carambola juice is a popular beverage in Taiwan. The popularity of star fruit juice is not compatible with the rare discovery of star fruit-associated acute oxalate nephropathy. Commercial carambola juice usually is prepared by pickling and dilution processes that reduce oxalate content markedly, whereas pure fresh juice or mild diluted postpickled juice for traditional remedies, as used in our cases, contain high quantities of oxalate. An empty stomach and dehydrated state may pose an additional risk for development of renal injury. To avoid acute oxalate nephropathy, pure sour carambola juice or mild diluted postpickled juice should not be consumed in large amounts, especially on an empty stomach or in a dehydrated state.

  18. Efficiency of population-dependent sulfite against Brettanomyces bruxellensis in red wine.

    Science.gov (United States)

    Longin, Cédric; Degueurce, Claudine; Julliat, Frédérique; Guilloux-Benatier, Michèle; Rousseaux, Sandrine; Alexandre, Hervé

    2016-11-01

    Brettanomyces bruxellensis is considered as a spoilage yeast encountered mainly in red wine. It is able to reduce vinylphenols from phenolic acids to ethylphenols. These volatiles are responsible for the phenolic "Brett character" described as animal, farm, horse sweat and animal leather odors. Other molecules are responsible for organoleptic deviations described as "mousiness taint". SO 2 is the product most often used by winemakers to prevent B. bruxellensis growth. Usually, the recommended molecular dose of SO 2 (active SO 2 , mSO 2 ) is highly variable, from 0.3 to 0.8mg/L. But these doses do not take into account differences of strain resistance to sulfites or population levels. Moreover, SO 2 is known as a chemical stressor inducing a viable but nonculturable (VBNC) state of B. bruxellensis. These cells, which are non-detectable by plate counting, can lead to new contamination when the amount of sulfite decreases over time. Consequently, we first assessed the effect of SO 2 levels in red wine on two strains with phenotypically different sulfite resistances. Then, we studied the relationship between amounts of SO 2 (0, 0.5, 0.9 and 1.1mg/L active SO 2 ) and population levels (10 3 , 10 4 and 10 5 cells/mL) in red wine. Yeasts were enumerated by both plate counting and flow cytometry over time using viability dye. Our results showed different SO 2 resistances according to the strain used. A relationship between yeast population level and SO 2 resistance was demonstrated: the higher the yeast concentration, the lower the efficiency of SO 2 . Under certain conditions, the VBNC state of B. bruxellensis was highlighted in red wine. Yeasts in this VBNC state did not produce 4-EP. Moreover, cells became culturable again over time. All these results provide new information enabling better management of sulfite addition during wine aging. Copyright © 2016. Published by Elsevier Ltd.

  19. Radiation preservation of low nitrite bacon

    International Nuclear Information System (INIS)

    Singh, H.

    1988-01-01

    Sodium nitrite, a key ingredient of the mix used to cure bacon and other meats, promotes and fixes bacon's characteristic pink color, inhibits lipid peroxidation and prevents growth of micro-organisms, particularly Clostridium botulinum spores. Unfortunately, nitrite leads to the formation of carcinogenic nitrosamines in bacon. This has led to a search for alternatives to the use of nitrite. Irradiation with reduced level of nitrite is a promising alternative. Radurization of bacon containing 20 to 40 mg/kg of nitrite in evacuated packages, irradiated and stored at 4 0 C, gives a product with good organoleptic qualities and extended shelf life of > 90 days, as opposed to ∼ 30 days for the conventionally treated bacon. Radappertization of bacon containing 20 mg/kg of nitrite at a dose of about 30 kGy, irradiated at temperature of -20 0 or lower in evacuated packages, results in a product that is shelf stable at room temperature for months to years. It has organoleptic qualities comparable to commercial bacon in terms of color, flavor, odor and texture. Irradiation also reduces the nitrite and preformed nitrosamines present in bacon. Various aspects of preservation of bacon are reviewed in this report with emphasis on radiation processing. (author)

  20. Molecular Basis for Enzymatic Sulfite Oxidation -- HOW THREE CONSERVED ACTIVE SITE RESIDUES SHAPE ENZYME ACTIVITY

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Susan; Rapson, Trevor; Johnson-Winters, Kayunta; Astashkin, Andrei; Enemark, John; Kappler, Ulrike

    2008-11-10

    Sulfite dehydrogenases (SDHs) catalyze the oxidation and detoxification of sulfite to sulfate, a reaction critical to all forms of life. Sulfite-oxidizing enzymes contain three conserved active site amino acids (Arg-55, His-57, and Tyr-236) that are crucial for catalytic competency. Here we have studied the kinetic and structural effects of two novel and one previously reported substitution (R55M, H57A, Y236F) in these residues on SDH catalysis. Both Arg-55 and His-57 were found to have key roles in substrate binding. An R55M substitution increased Km(sulfite)(app) by 2-3 orders of magnitude, whereas His-57 was required for maintaining a high substrate affinity at low pH when the imidazole ring is fully protonated. This effect may be mediated by interactions of His-57 with Arg-55 that stabilize the position of the Arg-55 side chain or, alternatively, may reflect changes in the protonation state of sulfite. Unlike what is seen for SDHWT and SDHY236F, the catalytic turnover rates of SDHR55M and SDHH57A are relatively insensitive to pH (~;;60 and 200 s-1, respectively). On the structural level, striking kinetic effects appeared to correlate with disorder (in SDHH57A and SDHY236F) or absence of Arg-55 (SDHR55M), suggesting that Arg-55 and the hydrogen bonding interactions it engages in are crucial for substrate binding and catalysis. The structure of SDHR55M has sulfate bound at the active site, a fact that coincides with a significant increase in the inhibitory effect of sulfate in SDHR55M. Thus, Arg-55 also appears to be involved in enabling discrimination between the substrate and product in SDH.

  1. OXALATE MASS BALANCE DURING CHEMICAL CLEANING IN TANK 6F

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M.; Fink, S.

    2011-07-22

    The Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRR personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 6F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate. Some conclusions from this work are: (1) Approximately 65% of the oxalate added as oxalic acid was removed with the decanted liquid. (2) Approximately 1% of the oxalate (added to the tank as oxalic acid) formed precipitates with compounds such as nickel, manganese, sodium, and iron (II), and was dissolved with nitric acid. (3) As much as 30% of the oxalate may have decomposed forming carbon dioxide. The balance does not fully account for all the oxalate added. The offset represents the combined uncertainty in the analyses and sampling.

  2. Oxalic acid has an additional, detoxifying function in Sclerotinia sclerotiorum pathogenesis.

    Directory of Open Access Journals (Sweden)

    Annerose Heller

    Full Text Available The mechanism of the diseases caused by the necrotroph plant pathogen Sclerotinia sclerotiorum is not well understood. To investigate the role of oxalic acid during infection high resolution, light-, scanning-, transmission electron microscopy and various histochemical staining methods were used. Our inoculation method allowed us to follow degradation of host plant tissue around single hyphae and to observe the reaction of host cells in direct contact with single invading hyphae. After penetration the outer epidermal cell wall matrix appeared degraded around subcuticular hyphae (12-24 hpi. Calcium oxalate crystals were detected in advanced (36-48 hpi and late (72 hpi infection stages, but not in early stages. In early infection stages, surprisingly, no toxic effect of oxalic acid eventually secreted by S. sclerotiorum was observed. As oxalic acid is a common metabolite in plants, we propose that attacked host cells are able to metabolize oxalic acid in the early infection stage and translocate it to their vacuoles where it is stored as calcium oxalate. The effects, observed on healthy tissue upon external application of oxalic acid to non-infected, living tissue and cell wall degradation of dead host cells starting at the inner side of the walls support this idea. The results indicate that oxalic acid concentrations in the early stage of infection stay below the toxic level. In plant and fungi oxalic acid/calcium oxalate plays an important role in calcium regulation. Oxalic acid likely could quench calcium ions released during cell wall breakdown to protect growing hyphae from toxic calcium concentrations in the infection area. As calcium antimonate-precipitates were found in vesicles of young hyphae, we propose that calcium is translocated to the older parts of hyphae and detoxified by building non-toxic, stable oxalate crystals. We propose an infection model where oxalic acid plays a detoxifying role in late infection stages.

  3. Growth of strontium oxalate crystals in agar–agar gel

    Indian Academy of Sciences (India)

    Growth of strontium oxalate crystals in agar–agar gel. P V DALAL. ∗ and K B SARAF. Postgraduate Department of Physics, Pratap College, Amalner 425 401, India. MS received 16 March 2008; revised 5 April 2010. Abstract. Single crystals of strontium oxalate have been grown by using strontium chloride and oxalic acid in.

  4. Calcium oxalate contribution to calcium cycling in forests of contrasting nutrient status

    Science.gov (United States)

    Dauer, Jenny M.; Perakis, Steven S.

    2014-01-01

    Calcium oxalate (Ca oxalate) is an insoluble biomineral that forms in plants and fungi, and occurs in soils across many types of ecosystems. Assessing how Ca oxalate may shape ecosystem Ca cycling requires information on the distribution of Ca oxalate among plant biomass, detritus, and mineral soil, and how it varies with ecosystem Ca status. We compared two Douglas-fir forests of contrasting ecosystem Ca availability, and found that Ca oxalate was partitioned similarly among plant biomass, detritus and mineral soil major ecosystem compartments at both sites, and total pools of Ca oxalate were greater in the high-Ca forest. However, the proportional importance of Ca oxalate was greater in the low-Ca than high-Ca forest (18% versus 4% of actively cycling ecosystem Ca, respectively). And calcium oxalate in mineral soil, which is of particular interest as a potential long-term Ca reservoir, was a larger portion of total available Ca (exchangeable Ca plus Ca oxalate Ca) in the low-Ca site than the high-Ca site (9% versus 1% of available soil Ca, respectively). Calcium oxalate was the dominant form of Ca returned from plants to soil as leaf litterfall at the high-Ca site, yet calcium oxalate disappeared rapidly from decomposing litter (0.28 yr−1 or faster) at both sites. We conclude that accumulation of Ca oxalate in forest ecosystems appears most closely related to overall Ca supply for live biomass pools, and that the accumulation of Ca oxalate in forest floor and mineral soil is limited by rapid microbial degradation of putatively unavailable Ca oxalate.

  5. An electrochemical approach: Switching Structures of rare earth metal Praseodymium hexacyanoferrate and its application to sulfite sensor in Red Wine

    International Nuclear Information System (INIS)

    Devadas, Balamurugan; Sivakumar, Mani; Chen, Shen Ming; Cheemalapati, Srikanth

    2015-01-01

    Graphical abstract: Nucleation and growth of PrHCF and its application to sulfite oxidation in wine samples. - Highlights: • Electrochemical synthesis of PrHCF. • Switching structures of PrHCF. • Sulfite electrochemical sensor. • Wide linear range and low limit of detection. • Real sample application. - Abstract: Herein, we report a shape-controlled preparation of Praseodymium hexacyanoferrate (PrHCF) using a simple electrochemical technique. The electrochemically fabricated PrHCF modified glassy carbon electrodes (GCE) shows an excellent electrocatalytic activity towards sulfite oxidation. The morphology of PrHCF particles were controlled by carefully changing various synthesis conditions including electrochemical technique (cyclic voltammetry, amperometry and chemical), cations in the supporting electrolyte (K + , Na + , Li + and H + ), deposition cycles, molar ratio of precursors, and applied potential (-.2,0 and 0.2 V). The morphologies of the PrHCF was elucidated using scanning electron microscopy (SEM). The as-synthesized PrHCF was characterized using X-ray diffraction pattern (XRD), Infra-red (IR) and energy dispersive X-ray spectroscopy (EDX). The electrochemical oxidation of sulfite on PrHCF modified GCE was investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The sensitivity of the as-developed sulfite sensor was determined to be 0.036 μA μM −1 cm −2 . The low limit of detection was determined to be 2.15 μM. The real time application of PrHCF modified GCE was confirmed through the determination of sulfite from red wine and tap water samples

  6. Radiolysis of titanium potassium oxalate in aqueous solution. [. gamma. rays

    Energy Technology Data Exchange (ETDEWEB)

    Bundo, Y; Ono, I [Industrial Research Inst. of Kanagawa Prefecture, Yokohama (Japan); Ogawa, T

    1975-01-01

    The dissolution state of titanium potassium oxalate in aqueous solution is different according to the pH. The yellowish brown titanium complex produced by the reaction of titanium potassium oxalate and hydrogen peroxide seems to be different in its structure according to the pH. Considering these points, gamma-ray irradiation was carried out on the sample by dissolving titanium potassium oxalate in purified water under the conditions of oxygen saturation and nitrogen saturation, and the relation between irradiation dose and the production of titanium complex was determined. On the basis of the experimental result, the mechanism of forming hydrogen peroxide was presumed. The radiation source used was 2,000 Ci of /sup 60/Co. For photometric analysis, a 139 type photoelectric spectrophotometer of Hitachi Ltd. was used. From the experimental results, in neutral water, titanium potassium oxalate exists in the state that two oxalic acid ions are coordinated to titanyl ion, while in case of the pH lowered by the addition of sulfuric acid, it can exist in the state that one oxalic acid ion is coordinated to titanyl ion. The yield of hydrogen peroxide produced by irradiating titanium potassium oxalate aqueous solution with gamma-ray is the sum of the molecular product from water and the radiolysis product from titanium potassium oxalate.

  7. Surface analysis of transition metal oxalates: Damage aspects

    Energy Technology Data Exchange (ETDEWEB)

    Chenakin, S.P., E-mail: chenakin@imp.kiev.ua [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Institute of Metal Physics, Nat. Acad. Sci. of Ukraine, Akad. Vernadsky Blvd. 36, 03680 Kiev (Ukraine); Szukiewicz, R. [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Barbosa, R.; Kruse, N. [Université Libre de Bruxelles (ULB), Chimie-Physique des Matériaux, B-1050 Bruxelles (Belgium); Voiland School of Chemical Engineering and Bioengineering, Washington State University, 155 Wegner Hall, Pullman, WA 99164-6515 (United States)

    2016-05-15

    Highlights: • Gas evolution from the Mn, Co, Ni and Cu oxalate hydrates in vacuum, during exposure to X-rays and after termination of X-ray irradiation is studied. • A comparative study of the damage caused by X-rays in NiC{sub 2}O{sub 4} and CuC{sub 2}O{sub 4} is carried out. • Effect of Ar{sup +} bombardment on the structure and composition of CoC{sub 2}O{sub 4} is studied. - Abstract: The behavior of transition metal oxalates in vacuum, under X-ray irradiation and low-energy Ar{sup +} ion bombardment was studied. A comparative mass-spectrometric analysis was carried out of gas evolution from the surface of Mn, Co, Ni and Cu oxalate hydrates in vacuum, during exposure to X-rays and after termination of X-ray irradiation. The rates of H{sub 2}O and CO{sub 2} liberation from the oxalates were found to be in an inverse correlation with the temperatures of dehydration and decomposition, respectively. X-ray photoelectron spectroscopy (XPS) was employed to study the X-ray induced damage in NiC{sub 2}O{sub 4} and CuC{sub 2}O{sub 4} by measuring the various XP spectral characteristics and surface composition of the oxalates as a function of time of exposure to X-rays. It was shown that Cu oxalate underwent a significantly faster degradation than Ni oxalate and demonstrated a high degree of X-ray induced reduction from the Cu{sup 2+} to the Cu{sup 1+} chemical state. 500 eV Ar{sup +} sputter cleaning of CoC{sub 2}O{sub 4} for 10 min was found to cause a strong transformation of the oxalate structure which manifested itself in an appreciable alteration of the XP core-level and valence band spectra. The analysis of changes in stoichiometry and comparison of XP spectra of bombarded oxalate with respective spectra of a reference carbonate CoCO{sub 3} implied that the bombardment-induced decomposition of CoC{sub 2}O{sub 4} gave rise to the formation of CoO-like and disordered CoCO{sub 3}-like phases.

  8. Improved glycerol production from cane molasses by the sulfite process with vacuum or continuous carbon dioxide sparging during fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, G.P.; Naik, S.C.; Lashkari, B.Z.

    1985-01-01

    The conventional sulfite process for glycerol production from molasses using Saccharomyces cerevisiae var. Hansen was modified to obtain product concentrations of up to 230 g/l and productivity of 15 g/l.d by fermenting under vacuum (80 mm) or with continuous sparging of CO2 (0.4 vvm). Under these conditions the requirement of sulfite for optimum production of glycerol was reduced by two thirds (20 g/l), the ethanol concentration in the medium was kept below 30 g/l and the competence of yeast cells to ferment was conserved throughout the fermentation period for up to 20 days. In addition to the above, the rate of incorporation of sulfite had a significant effect on glucose fermentation and glycerol yields. There was an optimal relationship between glycerol yields and the molar ratio of sulfite to glucose consumed, which for cane molasses was 0.67. This ratio was characteristic of the medium composition.

  9. Improved glycerol production from cane molasses by the sulfite process with vacuum or continuous carbon dioxide sparging during fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, G.P.; Naik, S.C.; Lashkari, B.Z.

    1985-01-01

    The conventional sulfite process for glycerol production from molasses using Saccharomyces cerevisiae var. Hansen was modified to obtain product concentrations of up to 230 g/l and productivity of 15 g/l x d by fermenting under vacuum (80 mm) or with continuous sparging of CO/sub 2/ (0.4 vvm). Under these conditions the requirement of sulfite for optimum production of glycerol was reduced by two thirds (20 g/l), the ethanol concentration in the medium was kept below 30 g/l and the competence of yeast cells to ferment was conserved throughout the fermentation period for up to 20 days. In addition to the above, the rate of incorporation of sulfite had a significant effect on glucose fermentation and glycerol yields. There was an optimal relationship between glycerol yields and the molar ratio of sulfite to glucose consumed, which for cane molasses was 0.67. This ratio was characteristic of the medium composition. 10 references, 4 figures, 3 tables.

  10. Effect of heat treatment on the structure of incorporated oxalate species and photoluminescent properties of porous alumina films formed in oxalic acid

    Science.gov (United States)

    Vrublevsky, I.; Jagminas, A.; Hemeltjen, S.; Goedel, W. A.

    2008-09-01

    The present work focuses on the use of IR spectroscopy and photoluminescence spectral measurements for studying the treatment temperature effect on the compositional and luminescent properties of oxalic acid alumina films. In line with the recent researches we have also found that heat treatment of porous alumina films formed in oxalic acid leads to considerable changes in their photoluminescence properties: upon annealing the intensity of photoluminescence (PL) increases reaching a maximum at the temperature of around 500 °C and then decreases. IR spectra of as-grown and heat-treated films have proved that PL emission in the anodic alumina films is related with the state of 'structural' oxalate species incorporated in the oxide lattice. These results allowed us to conclude that PL behavior of oxalic acid alumina films can be explained through the concept of variations in the bonding molecular orbitals of incorporated oxalate species including σ- and π-bonds.

  11. Nitrite survival and nitrous oxide production of denitrifying phosphorus removal sludges in long-term nitrite/nitrate-fed sequencing batch reactors.

    Science.gov (United States)

    Wang, Yayi; Zhou, Shuai; Ye, Liu; Wang, Hong; Stephenson, Tom; Jiang, Xuxin

    2014-12-15

    Nitrite-based phosphorus (P) removal could be useful for innovative biological P removal systems where energy and carbon savings are a priority. However, using nitrite for denitrification may cause nitrous oxide (N2O) accumulation and emissions. A denitrifying nitrite-fed P removal system [Formula: see text] was successfully set up in a sequencing batch reactor (SBR) and was run for 210 days. The maximum pulse addition of nitrite to [Formula: see text] was 11 mg NO2(-)-N/L in the bulk, and a total of 34 mg NO2(-)-N/L of nitrite was added over three additions. Fluorescent in situ hybridization results indicated that the P-accumulating organisms (PAOs) abundance was 75 ± 1.1% in [Formula: see text] , approximately 13.6% higher than that in a parallel P removal SBR using nitrate [Formula: see text] . Type II Accumulibacter (PAOII) (unable to use nitrate as an electron acceptor) was the main PAOs species in [Formula: see text] , contributing 72% to total PAOs. Compared with [Formula: see text] , [Formula: see text] biomass had enhanced nitrite/free nitrous acid (FNA) endurance, as demonstrated by its higher nitrite denitrification and P uptake rates. N2O accumulated temporarily in [Formula: see text] after each pulse of nitrite. Peak N2O concentrations in the bulk for [Formula: see text] were generally 6-11 times higher than that in [Formula: see text] ; these accumulations were rapidly denitrified to nitrogen gases. N2O concentration increased rapidly in nitrate-cultivated biomass when 5 or 10 mg NO2(-)-N/L per pulse was added. Whereas, N2O accumulation did not occur in nitrite-cultivated biomass until up to 30 mg NO2(-)-N/L per pulse was added. Long-term acclimation to nitrite and pulse addition of nitrite in [Formula: see text] reduced the risk of nitrite accumulation, and mitigated N2O accumulation and emissions from denitrifying P removal by nitrite. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. New indium selenite-oxalate and indium oxalate with two- and three-dimensional structures

    International Nuclear Information System (INIS)

    Cao Junjun; Li Guodong; Chen Jiesheng

    2009-01-01

    Two new indium(III) compounds with extended structures, [In 2 (SeO 3 ) 2 (C 2 O 4 )(H 2 O) 2 ].2H 2 O (I) and [NH 3 (CH 2 ) 2 NH 3 ][In(C 2 O 4 ) 2 ] 2 .5H 2 O (II), have been prepared under mild hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. Compound I crystallizes in the triclinic system, space group P-1, with a=5.2596(11) A, b=6.8649(14) A, c=9.3289(19) A, α=101.78(3) o , β=102.03(3) o , γ=104.52(3) o , while compound II crystallizes in the orthorhombic system, space group Fdd2, with a=15.856(3) A, b=31.183(6) A, c=8.6688(17) A. In compound I, indium-selenite chains are bridged by oxalate units to form two-dimensional (2D) In 2 (SeO 3 ) 2 C 2 O 4 layers, separated by non-coordinating water molecules. In compound II, the indium atoms are connected through the oxalate units to generate a 3D open framework containing cross-linked 12- and 8-membered channels. - Graphical abstract: Two new indium(III) compounds have been hydrothermally synthesized and structurally characterized. In I, the indium-selenite chains are bridged by oxalate units to form 2D In 2 (SeO 3 ) 2 C 2 O 4 layers. In II, the indium atoms are connected through the oxalate units to generate a 3D open framework containing cross-linked 12- and 8-membered ring channels

  13. Generation of PHB from Spent Sulfite Liquor Using Halophilic Microorganisms.

    Science.gov (United States)

    Weissgram, Michaela; Gstöttner, Janina; Lorantfy, Bettina; Tenhaken, Raimund; Herwig, Christoph; Weber, Hedda K

    2015-06-08

    Halophilic microorganisms thrive at elevated concentrations of sodium chloride up to saturation and are capable of growing on a wide variety of carbon sources like various organic acids, hexose and also pentose sugars. Hence, the biotechnological application of these microorganisms can cover many aspects, such as the treatment of hypersaline waste streams of different origin. Due to the fact that the high osmotic pressure of hypersaline environments reduces the risk of contamination, the capacity for cost-effective non-sterile cultivation can make extreme halophilic microorganisms potentially valuable organisms for biotechnological applications. In this contribution, the stepwise use of screening approaches, employing design of experiment (DoE) on model media and subsequently using industrial waste as substrate have been implemented to investigate the applicability of halophiles to generate PHB from the industrial waste stream spent sulfite liquor (SSL). The production of PHB on model media as well as dilutions of industrial substrate in a complex medium has been screened for by fluorescence microscopy using Nile Blue staining. Screening was used to investigate the ability of halophilic microorganisms to withstand the inhibiting substances of the waste stream without negatively affecting PHB production. It could be shown that neither single inhibiting substances nor a mixture thereof inhibited growth in the investigated range, hence, leaving the question on the inhibiting mechanisms open. However, it could be demonstrated that some haloarchaea and halophilic bacteria are able to produce PHB when cultivated on 3.3% w/w dry matter spent sulfite liquor, whereas H. halophila was even able to thrive on 6.6% w/w dry matter spent sulfite liquor and still produce PHB.

  14. Neurotoxic effects of carambola in rats: the role of oxalate.

    Science.gov (United States)

    Chen, Chien-Liang; Chou, Kang-Ju; Wang, Jyh-Seng; Yeh, Jeng-Hsien; Fang, Hua-Chang; Chung, Hsiao-Min

    2002-05-01

    Carambola (star fruit) has been reported to contain neurotoxins that cause convulsions, hiccups, or death in uremic patients, and prolong barbiturate-induced sleeping time in rats. The constituent responsible for these effects remains uncertain. Carambola contains a large quantity of oxalate, which can induce depression of cerebral function and seizures. This study was conducted to investigate the role of oxalate in carambola toxicity in rats. The effects on barbiturate-induced sleeping time and death caused by intraperitoneal administration of carambola juice were observed in Sprague-Dawley rats. To obtain a dose-dependent response curve and evaluate the lethal dose, rats were treated with serial amounts of pure carambola juice diluted with normal saline in a volume of 1:1. To test the role of oxalate in the neurotoxic effect of carambola, either 5.33 g/kg carambola after oxalate removal or 5.33 g/kg of pure carambola juice diluted with normal saline were administered intraperitoneally, while the control group was given normal saline before pentobarbital injection. The effects of carambola and oxalate-removed carambola on barbiturate-induced sleeping time were compared with those of saline. To assess the lethal effect of oxalate in carambola, we gave rats chemical oxalate at comparable concentrations to the oxalate content of carambola. Carambola juice administration prolonged barbiturate-induced sleeping time in a dose-dependent manner. The sleeping time of rats that received normal saline and 1.33 g/kg, 2.67 g/kg, 5.33 g/kg, and 10.67 g/kg of carambola juice were 66 +/- 16.6, 93.7 +/- 13.4, 113.3 +/- 11.4, 117.5 +/- 29.0, and 172.5 +/- 38.8 minutes, respectively. The three higher-dose groups had longer sleeping times than controls (p carambola juice. Four of eight rats in the 10.67-g/kg group and all rats in the 21.33 g/kg and chemical oxalate groups died after seizure. Lethal doses of carambola juice were rendered harmless by the oxalate removal procedure

  15. 3.2.1. Synthesis, crystal and molecular structure of catena-(bis(µ1-oxalic acid)-µ3-hydrogen oxalate-di-aqua-sodium(I)).

    OpenAIRE

    Olga Kovalchukova*, Sergey Aldoshin, Andrey Utenyshev, Konstantin Bogenko, Valeriy Tkachev

    2015-01-01

    The crystal and molecular structure of catena-(bis(µ- oxalic acid)-µ-hydrogen oxalate-di-aqua-sodium(I)) was detected by X-Ray analysis. The compound crystallizes in the triclinic space group P-1, with a(Å) 6.2378(12); b(Å) 7,1115(14); c(Å) 10.489(2); α(°) 94.65(3); β(°) 100.12(3); γ(°) 97.78(3). The sodium cation in the title compound is eight coordinated and forms a square antiprism. It is surrounded by two molecules of oxalic acid, one hydrogen oxalate anion and one water molecule. Both ox...

  16. Effect of Dry Red Grape Pomace as a Nitrite Substitute on the Microbiological and Physicochemical Properties and Residual Nitrite of Dry-cured Sausage

    Directory of Open Access Journals (Sweden)

    Fatemeh Riazi

    2016-07-01

    Full Text Available Background and Objectives: Sodium nitrite and potassium nitrite have been traditionally used for inhibition of Clostridium botulinum and also as an agent to stabilize the color of meat products; however, usage of these additives at high levels could lead to toxicity and cancer originating from the formation of nitrosamines. Nowadays, application of natural preservatives in order to reduce the nitrite content in meat products is increasing. Thus, we used dry red grape pomace (DRGP as a natural alternative to sodium nitrite. Materials and Methods: The effect of two levels of DRGP (1 and 2% on the proximate composition, microbial counts, pH values and residual nitrite level of the samples formulated with two levels of sodium nitrite (30 and 60 mg/kg, as well as the comparison of these sausages with the blank (nitrite-free  and control (full nitrite added samples on the 1rst, 10th, 20th and 30th days of storage at 3-5 °C were evaluated. Results: The results showed that all chemical compositions were in the ranges reported by other researchers, and nitrite was very effective in preventing the microbial growth. Also about 50 % of the ingoing nitrite could be analyzed in the samples after processing. Moreover, the residual nitrite level declined both during the storage of sausage and after the addition of DRGP. Conclusions: The use of DRGP in combination with nitrite for sausages was more effective in keeping the quality and safety of the refrigerated consumer products as indicated by the lower nitrite levels, microbial count and similar composition as compared to the samples treated with nitrite and without nitrite. Keywords: Dry red grape pomace (DRGP, Sausage, Nitrite, Microbial count

  17. Determination of Nitrite in Whole Blood by High-Performance Liquid Chromatography with Electrochemical Detection and a Case of Nitrite Poisoning.

    Science.gov (United States)

    Yan, Hui; Zhuo, Xiangyi; Shen, Baohua; Xiang, Ping; Shen, Min

    2016-01-01

    Although nitrite is widely used in meat processing, it is a major toxicity hazard to children and is responsible for the blue-baby syndrome. A simple and effective method to determine nitrite in whole blood has been devised using ion chromatography with suppressed conductivity detection. The blood sample was deproteinized by adding acetonitrile and purified with mini-cartridges to remove hydrophobic compounds, chloride ions, and metal ions. An aliquot of the filtrate was injected onto the ion chromatography. The retention time for nitrite was 13.8 min and the detection limit of nitrite in whole blood was 0.4 μmol/L. The calibration curve was linear (r(2) = 0.9999) over the concentration working range. The blood nitrite concentration of a victim who attempted suicide by ingesting sodium nitrite powder was determined using the present method. The basal levels for nitrite in human blood was determined with 7.1 ± 0.9 μmol/L (n = 12). © 2015 American Academy of Forensic Sciences.

  18. Effective Electrochemistry of Human Sulfite Oxidase Immobilized on Quantum-Dots-Modified Indium Tin Oxide Electrode.

    Science.gov (United States)

    Zeng, Ting; Leimkühler, Silke; Koetz, Joachim; Wollenberger, Ulla

    2015-09-30

    The bioelectrocatalytic sulfite oxidation by human sulfite oxidase (hSO) on indium tin oxide (ITO) is reported, which is facilitated by functionalizing of the electrode surface with polyethylenimine (PEI)-entrapped CdS nanoparticles and enzyme. hSO was assembled onto the electrode with a high surface loading of electroactive enzyme. In the presence of sulfite but without additional mediators, a high bioelectrocatalytic current was generated. Reference experiments with only PEI showed direct electron transfer and catalytic activity of hSO, but these were less pronounced. The application of the polyelectrolyte-entrapped quantum dots (QDs) on ITO electrodes provides a compatible surface for enzyme binding with promotion of electron transfer. Variations of the buffer solution conditions, e.g., ionic strength, pH, viscosity, and the effect of oxygen, were studied in order to understand intramolecular and heterogeneous electron transfer from hSO to the electrode. The results are consistent with a model derived for the enzyme by using flash photolysis in solution and spectroelectrochemistry and molecular dynamic simulations of hSO on monolayer-modified gold electrodes. Moreover, for the first time a photoelectrochemical electrode involving immobilized hSO is demonstrated where photoexcitation of the CdS/hSO-modified electrode lead to an enhanced generation of bioelectrocatalytic currents upon sulfite addition. Oxidation starts already at the redox potential of the electron transfer domain of hSO and is greatly increased by application of a small overpotential to the CdS/hSO-modified ITO.

  19. Oxalic acid biosynthesis and oxalacetate acetylhydrolase activity in Streptomyces cattleya

    International Nuclear Information System (INIS)

    Houck, D.R.; Inamine, E.

    1987-01-01

    In addition to producing the antibiotic thienamycin, Streptomyces cattleya accumulates large amounts of oxalic acid during the course of a fermentation. Washed cell suspensions were utilized to determine the specific incorporation of carbon-14 into oxalate from a number of labeled organic and amino acids. L-[U- 14 C]aspartate proved to be the best precursor, whereas only a small percentage of label from [1,5- 14 C]citrate was found in oxalate. Cell-free extracts catalyzed the formation of [ 14 C]oxalate and [ 14 C]acetate from L-[U- 14 C]aspartate. When L-[4- 14 C]aspartate was the substrate only [ 14 C]acetate was formed. The cell-free extracts were found to contain oxalacetate acetylhydrolase, the enzyme that catalyzes the hydrolysis of oxalacetate to oxalate and acetate. The enzyme is constitutive and is analogous to enzymes in fungi that produce oxalate from oxalacetate. Properties of the crude enzyme were examined

  20. A manganese sulfite with extended metal-oxygen-metal bonds exhibiting hydrogen uptake

    International Nuclear Information System (INIS)

    Rao, K. Prabhakara; Govindaraj, A.; Rao, C.N.R.

    2007-01-01

    A manganese sulfite of the formula Mn 5 (OH) 4 (SO 3 ) 3 .2H 2 O, I{a=7.5759(7) A, b=8.4749(8) A, c=10.852(1) A, β=100.732(2) o , Z=2, space group=P2 1 /m (no. 11), R 1 =0.0399 and wR 2 =0.1121 [for R indexes I>2σ(I)]}, comprising Mn 3 O 14 units and extended Mn-O-Mn bonds along the three dimensions has been synthesized under hydrothermal conditions. It has narrow channels along the b-axis and exhibits hydrogen storage of 2.1 wt% at 300 K and 134 bar. - Graphical abstract: A three-dimensional manganese sulfite with one-dimensional channels showing selective hydrogen absorption has been synthesized and characterized

  1. Enhancing expression of SSU1 genes in Saccharomyces uvarum leads to an increase in sulfite tolerance and a transcriptome profile change.

    Science.gov (United States)

    Liu, X Z; Sang, M; Zhang, X A; Zhang, T K; Zhang, H Y; He, X; Li, S X; Sun, X D; Zhang, Z M

    2017-05-01

    Saccharomyces uvarum is a good wine yeast species that may have great potential for the future. However, sulfur tolerance of most S. uvarum strains is very poor. In addition there is still little information about the SSU1 gene of S. uvarum, which encodes a putative transporter conferring sulfite tolerance. In order to analyze the function of the SSU1 gene, two expression vectors that contained different SSU1 genes were constructed and transferred into a sulfite-tolerant S. uvarum strain, A9. Then sulfite tolerance, SO2 production, and PCR, sequencing, RT-qPCR and transcriptome analyses were used to access the function of the S. uvarum SSU1 gene. Our results illustrated that enhancing expression of the SSU1 gene can promote sulfite resistance in S. uvarum, and an insertion fragment ahead of the additional SSU1 gene, as seen in some alleles, could affect the expression of other genes and the sulfite tolerance level of S. uvarum. This is the first report on enhancing the expression of the SSU1 gene of S. uvarum. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Isolation and some characteristics of anaerobic oxalate-degrading bacteria from the rumen.

    OpenAIRE

    Dawson, K A; Allison, M J; Hartman, P A

    1980-01-01

    Obligately anaerobic oxalate-degrading bacteria were isolated from an enriched population of rumen bacteria in an oxalate-containing medium that had been depleted of other readily metabolized substrates. These organisms, which are the first reported anaerobic oxalate degraders isolated from the rumen, were gram negative, nonmotile rods. They grew in a medium containing sodium oxalate, yeast extract, cysteine, and minerals. The only substrate that supported growth was oxalate. Growth was direc...

  3. Microbial growth on oxalate by a route not involving glyoxylate carboligase

    Science.gov (United States)

    Blackmore, Maureen A.; Quayle, J. R.

    1970-01-01

    1. The metabolism of oxalate by the pink-pigmented organisms, Pseudomonas AM1, Pseudomonas AM2, Protaminobacter ruber and Pseudomonas extorquens has been compared with that of the non-pigmented Pseudomonas oxalaticus. 2. During growth on oxalate, all the organisms contain oxalyl-CoA decarboxylase, formate dehydrogenase and oxalyl-CoA reductase. This is consistent with oxidation of oxalate to carbon dioxide taking place via oxalyl-CoA, formyl-CoA and formate as intermediates, and also reduction of oxalate to glyoxylate taking place via oxalyl-CoA. 3. The pink-pigmented organisms, when grown on oxalate, contain l-serine–glyoxylate aminotransferase and hydroxypyruvate reductase but do not contain glyoxylate carboligase. The converse of this obtains in oxalate-grown Ps. oxalaticus. This indicates that, in contrast with Ps. oxalaticus, synthesis of C3 compounds from oxalate by the pink-pigmented organisms occurs by a variant of the `serine pathway' used by Pseudomonas AM1 during growth on C1 compounds. 4. Evidence in favour of this scheme is provided by the finding that a mutant of Pseudomonas AM1 that lacks hydroxypyruvate reductase is not able to grow on oxalate. PMID:5472155

  4. Spectroscopic properties of Pr -doped erbium oxalate crystals

    Indian Academy of Sciences (India)

    Spectroscopic properties of praseodymium ions-doped erbium oxalate ... solution with specific gravity 1.04 g/cm3 was mixed homogeneously with 0.5 M oxalic ... of concentrated nitric acid were transferred carefully and gently through the wall ...

  5. Kinetic and structural studies reveal a unique binding mode of sulfite to the nickel center in urease.

    Science.gov (United States)

    Mazzei, Luca; Cianci, Michele; Benini, Stefano; Bertini, Leonardo; Musiani, Francesco; Ciurli, Stefano

    2016-01-01

    Urease is the most efficient enzyme known to date, and catalyzes the hydrolysis of urea using two Ni(II) ions in the active site. Urease is a virulence factor in several human pathogens, while causing severe environmental and agronomic problems. Sporosarcina pasteurii urease has been used extensively in the structural characterization of the enzyme. Sodium sulfite has been widely used as a preservative in urease solutions to prevent oxygen-induced oxidation, but its role as an inhibitor has also been suggested. In the present study, isothermal titration microcalorimetry was used to establish sulfite as a competitive inhibitor for S. pasteurii urease, with an inhibition constant of 0.19mM at pH7. The structure of the urease-sulfite complex, determined at 1.65Å resolution, shows the inhibitor bound to the dinuclear Ni(II) center of urease in a tridentate mode involving bonds between the two Ni(II) ions in the active site and all three oxygen atoms of the inhibitor, supporting the observed competitive inhibition kinetics. This coordination mode of sulfite has never been observed, either in proteins or in small molecule complexes, and could inspire synthetic coordination chemists as well as biochemists to develop urease inhibitors based on this chemical moiety. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. 40 CFR 721.4740 - Alkali metal nitrites.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in the...

  7. Interaction of Celestine Concentrate and Reagent Grade SrSO4 with Oxalate Solutions

    Directory of Open Access Journals (Sweden)

    Abdullah Obut

    2012-12-01

    Full Text Available The interaction of reagent grade strontium sulphate and celestine concentrate with aqueous solutions of oxalic acid, sodiumoxalate and ammonium oxalate for the production of strontium carbonate were investigated for different oxalate compound:SrSO4 moleratios and reaction times using x-ray diffraction analysis and dissolution tests. Under the same experimental conditions, it was foundthat aqueous oxalic acid and sodium oxalate solutions had no or little effect on reagent grade strontium sulphate or celestineconcentrate, but aqueous ammonium oxalate solution converted them into strontium oxalate hydrate. Strontium carbonate was obtainedat conversion ratios of 74.7% for the celestine concentrate and 84.6 % for the reagent grade strontium sulphate by the decompositionof the obtained strontium oxalate hydrate at 600 °C under air atmosphere.

  8. Effect of the kinetics of ammonium and nitrite oxidation on nitritation success or failure for different biofilm reactor geometries

    DEFF Research Database (Denmark)

    Lackner, Susanne; Smets, Barth F.

    2012-01-01

    was on the influence of key biokinetic parameters (maximum specific growth rates, oxygen and nitrogen affinity constants of AOB (ammonium oxidizing bacteria) and NOB (nitrite oxidizing bacteria)) and their ratios on nitritation efficiency in these geometries. This exhaustive simulation study revealed that nitritation...... strongly depends on the chosen kinetic parameters of AOB and NOB. The maximum specific growth rates (μmax,AOB and μmax,NOB) had the strongest impact on nitritation efficiency (NE). In comparison, the counter-diffusion geometry yielded more parameter combinations (27.5%) that resulted in high NE than the co...

  9. Methanol as electron donor for thermophilic biological sulfate and sulfite reduction

    NARCIS (Netherlands)

    Weijma, J.

    2000-01-01

    Sulfur oxyanions (e.g. sulfate, sulfite) can be removed from aqueous waste- and process streams by biological reduction with a suitable electron donor to sulfide, followed by partial chemical or biological oxidation of sulfide to elemental sulfur. The aim of the research described in this

  10. Influence of additives on the structure and microstructure of lanthanides and actinides oxalates

    International Nuclear Information System (INIS)

    Haidon, Blaise; Vitart, Anne-Lise; Rivenet, Murielle; Arab-Chapelet, Benedicte; Roussel, Pascal; Delahaye, Thibaud; Grandjean, Stephane; Abraham, Francis

    2015-07-01

    Oxalic conversion is a well-known process in the nuclear industry where it is used for precipitating plutonium as an oxalate thereafter calcinated into an oxide. As there is a strong relationship between the morphology of the oxalate precursor and that of the resulting oxide, it is of interest to control the oxalate structure and microstructure during the precipitation step. The influence of additives on the precipitation of neodymium (III) oxalates, non-radioactive analogs of actinides (III) oxalates, was explored. With the use of nitrilotri-methylphosphonic acid (NTMP), the structure and microstructure of the neodymium oxalates are different from that obtained without additive. (authors)

  11. Nitrite in feed: From Animal health to human health

    Energy Technology Data Exchange (ETDEWEB)

    Cockburn, Andrew [Institute for Research on Environment and Sustainability, Devonshire Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE17RU (United Kingdom); Brambilla, Gianfranco [Istituto Superiore di Sanità, Toxicological chemistry unit, Viale Regina Elena 299, 00161 Rome (Italy); Fernández, Maria-Luisa [Departamento de Medio Ambiente, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Ministerio de Ciencia e Innovación, Carretera de la Coruña, 28040 Madrid (Spain); Arcella, Davide [Unit on Data Collection and Exposure, European Food Safety Authority, Largo N. Palli 5/A43100 Parma (Italy); Bordajandi, Luisa R. [Unit on Contaminants in the Food chain, European Food Safety Authority, Largo N. Palli 5/A, 43100 Parma (Italy); Cottrill, Bruce [Policy Delivery Group, Animal Health and Welfare, ADAS, Wolverhampton (United Kingdom); Peteghem, Carlos van [University of Gent, Harelbekestraat 72, 9000 Gent (Belgium); Dorne, Jean-Lou, E-mail: jean-lou.dorne@efsa.europa.eu [Unit on Contaminants in the Food chain, European Food Safety Authority, Largo N. Palli 5/A, 43100 Parma (Italy)

    2013-08-01

    Nitrite is widely consumed from the diet by animals and humans. However the largest contribution to exposure results from the in vivo conversion of exogenously derived nitrate to nitrite. Because of its potential to cause to methaemoglobin (MetHb) formation at excessive levels of intake, nitrite is regulated in feed and water as an undesirable substance. Forages and contaminated water have been shown to contain high levels of nitrate and represent the largest contributor to nitrite exposure for food-producing animals. Interspecies differences in sensitivity to nitrite intoxication principally result from physiological and anatomical differences in nitrite handling. In the case of livestock both pigs and cattle are relatively susceptible. With pigs this is due to a combination of low levels of bacterial nitrite reductase and hence potential to reduce nitrite to ammonia as well as reduced capacity to detoxify MetHb back to haemoglobin (Hb) due to intrinsically low levels of MetHb reductase. In cattle the sensitivity is due to the potential for high dietary intake and high levels of rumen conversion of nitrate to nitrite, and an adaptable gut flora which at normal loadings shunts nitrite to ammonia for biosynthesis. However when this escape mechanism gets overloaded, nitrite builds up and can enter the blood stream resulting in methemoglobinemia. Looking at livestock case histories reported in the literature no-observed-effect levels of 3.3 mg/kg body weight (b.w.) per day for nitrite in pigs and cattle were estimated and related to the total daily nitrite intake that would result from complete feed at the EU maximum permissible level. This resulted in margins of safety of 9-fold and 5-fold for pigs and cattle, respectively. Recognising that the bulkiness of animal feed limits their consumption, these margins in conjunction with good agricultural practise were considered satisfactory for the protection of livestock health. A human health risk assessment was also

  12. Nitrite in feed: From Animal health to human health

    International Nuclear Information System (INIS)

    Cockburn, Andrew; Brambilla, Gianfranco; Fernández, Maria-Luisa; Arcella, Davide; Bordajandi, Luisa R.; Cottrill, Bruce; Peteghem, Carlos van; Dorne, Jean-Lou

    2013-01-01

    Nitrite is widely consumed from the diet by animals and humans. However the largest contribution to exposure results from the in vivo conversion of exogenously derived nitrate to nitrite. Because of its potential to cause to methaemoglobin (MetHb) formation at excessive levels of intake, nitrite is regulated in feed and water as an undesirable substance. Forages and contaminated water have been shown to contain high levels of nitrate and represent the largest contributor to nitrite exposure for food-producing animals. Interspecies differences in sensitivity to nitrite intoxication principally result from physiological and anatomical differences in nitrite handling. In the case of livestock both pigs and cattle are relatively susceptible. With pigs this is due to a combination of low levels of bacterial nitrite reductase and hence potential to reduce nitrite to ammonia as well as reduced capacity to detoxify MetHb back to haemoglobin (Hb) due to intrinsically low levels of MetHb reductase. In cattle the sensitivity is due to the potential for high dietary intake and high levels of rumen conversion of nitrate to nitrite, and an adaptable gut flora which at normal loadings shunts nitrite to ammonia for biosynthesis. However when this escape mechanism gets overloaded, nitrite builds up and can enter the blood stream resulting in methemoglobinemia. Looking at livestock case histories reported in the literature no-observed-effect levels of 3.3 mg/kg body weight (b.w.) per day for nitrite in pigs and cattle were estimated and related to the total daily nitrite intake that would result from complete feed at the EU maximum permissible level. This resulted in margins of safety of 9-fold and 5-fold for pigs and cattle, respectively. Recognising that the bulkiness of animal feed limits their consumption, these margins in conjunction with good agricultural practise were considered satisfactory for the protection of livestock health. A human health risk assessment was also

  13. Oxaloacetate hydrolase, the C-C bond lyase of oxalate secreting fungi

    NARCIS (Netherlands)

    Han, Y.; Joosten, H.J.; Niu, W.; Zhao, Z.; Mariano, P.S.; McCalman, M.; Kan, van J.; Schaap, P.J.; Dunaway-Mariano, D.

    2007-01-01

    Oxalate secretion by fungi is known to be associated with fungal pathogenesis. In addition, oxalate toxicity is a concern for the commercial application of fungi in the food and drug industries. Although oxalate is generated through several different biochemical pathways, oxaloacetate

  14. Use of nitrite inhalants ("poppers") among American youth.

    Science.gov (United States)

    Wu, Li-Tzy; Schlenger, William E; Ringwalt, Chris L

    2005-07-01

    We examined the patterns and correlates of nitrite inhalant use among adolescents aged 12 to 17 years. Study data were drawn from the 2000 and 2001 National Household Surveys on Drug Abuse. Logistic regression was used to identify the characteristics associated with nitrite inhalant use. Among adolescents aged 12 to 17 years, 1.5% reported any lifetime use of nitrite inhalants. The prevalence of lifetime nitrite inhalant use increased to 12% and 14% among adolescents who were dependent on alcohol and any drug in the past year, respectively. Many nitrite inhalant users used at least three other types of inhalants (68%) and also met the criteria for alcohol (33%) and drug (35%) abuse or dependence. Increased odds of nitrite inhalant use were associated with residing in nonmetropolitan areas, recent utilization of mental health services, delinquent behaviors, past year alcohol and drug abuse and dependence, and multi-drug use. Adolescents who had used nitrite inhalants at least once in their lifetime tend to engage in delinquent activities and report co-occurring multiple drug abuse and mental health problems in the past year.

  15. Mutagenesis breeding research of Lactobacillus brevis of nitrite reduction

    Directory of Open Access Journals (Sweden)

    LI Zeli

    2015-10-01

    Full Text Available The pollution of nitrite in food became one of the focus of food safety issues,the use of biotechnology methods degrading nitrite became hotspot.The primitive strain was Lactobacillus brevis C2,preserved in our laboratory,had the ability to degrade nitrite,through composite mutagenesis of 15 W,254 nm,20 cm ultraviolet mutagenesis (UV for 120 s and 0.8% diethyl sulfate(DES in 37℃ mutation for 40 min,after screening,we successfully obtained high efficient strain of nitrite degradation,named UV6-DS2,relative to the starting strain,under the condition of 400 mg/L nitrite,after 12 h degradation,nitrite degradation rate increased from 92.8% to 97.8%,to explore its application in food was able to effectively reduce concentration of nitrite in food.

  16. Evidence for a cytoplasmic pathway of oxalate biosynthesis in Aspergillus niger

    International Nuclear Information System (INIS)

    Kubicek, C.P.; Schreferl-Kunar, G.; Woehrer, W.; Roehr, M.

    1988-01-01

    Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of P/sub i/ and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added 14 CO 2 was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle

  17. Decontamination effectiveness of mixtures of citric acid, oxalic acid and EDTA

    International Nuclear Information System (INIS)

    Speranzini, R.A.

    1990-01-01

    An experimental study of the decontamination effectiveness of citric acid, oxalic acid and EDTA mixtures was conducted to assess whether oxalic acid could be removed from decontamination solutions to minimize corrosion. In loop experiments, radioactive specimens from two boiling water reactors and one pressurized water reactor were suspended in solutions of single acids or in mixtures of reagents at total reagent concentrations of less than 0.1 wt% under conditions similar to those used to decontaminate reactor systems. Rate constants for dissolution of oxides and decontamination factors were measured. Based on the results, it was concluded that under certain conditions, oxalic acid was the most effective reagent for the dissolution of oxides. It was also found, however, that conditions under which effective dissolution occurred in solutions of oxalic acid and/or citric acid were difficult to define and control. EDTA was found to be an effective reagent for dissolution of oxides such that rates of dissolution in EDTA containing solutions at 117 degrees Celsius were comparable to rates in oxalic acid containing solutions. At 90 degrees Celsius, EDTA acted synergistically with oxalic acid such that the rate of dissolution of oxides in citric-acid/oxalic-acid/EDTA solutions was higher than in citric-acid/EDTA solutions. The rates of dissolution of oxides were significantly reduced when 60 mg/kg of ferric ion was added to the citric-acid/oxalic-acid, citric-acid/EDTA and citric-acid/oxalic-acid/EDTA solutions. It was concluded that effective decontaminations of BWR and PWR systems could be achieved with mixtures of citric acid and EDTA

  18. Nitrite uptake by nitrogen-depleted wheat seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, W A; Johnson, R E; Volk, R J

    1974-01-01

    Intact, 14-day-old nitrogen-depleted wheat (Triticum vulgare cv. Blueboy) seedlings were exposed to solutions of 0.5 mM KNO/sub 2/, 0.05 mM CaSO/sub 4/ and 1 mM sodium 2-(N-morpholino)-ethanesulfonate, pH 6.1. Nitrite uptake was determined from depletion of the ambient solution or from incorporation of /sup 15/N in the tissue. An initial nitrite uptake shoulder was followed by a relatively slow uptake rate which subsequently increased to a substantially greater rate. This accelerated phase was maintained through 24 h. Nitrite accumulated to a slight extent in the root tissues during the first few hours but declined to low values when the accelerated rate was fully developed, indicating an increase in nitrite reductase activity paralleling the increase in nitrite uptake capacity. About 50% of the nitrogen absorbed as nitrite was translocated to the shoots by 9 to 12 h. Development of the accelerated nitrite uptake rate was restricted in excised roots, in intact plants kept in darkness, by 400 ..mu..g puromycin ml/sup -1/ and by 1 mM L-ethionine. When puromycin and L-ethionine were added after the accelerated phase had been initiated, their effects were not as detrimental as when they were added at first exposure to KNO/sub 2/. The two inhibitors restricted translocation more than uptake. The data indicate an involvement of protein synthesis and a requirement for movement of a substance from shoots to roots for maximal development of the accelerated nitrite uptake phase. A requirement for protein synthesis in the transport of soluble organic nitrogen from roots to shoots is also suggested.

  19. Dietary nitrates, nitrites, and cardiovascular disease.

    Science.gov (United States)

    Hord, Norman G

    2011-12-01

    Dietary nitrate (NO(3)), nitrite (NO(2)), and arginine can serve as sources for production of NO(x) (a diverse group of metabolites including nitric oxide, nitrosothiols, and nitroalkenes) via ultraviolet light exposure to skin, mammalian nitrate/nitrite reductases in tissues, and nitric oxide synthase enzymes, respectively. NO(x) are responsible for the hypotensive, antiplatelet, and cytoprotective effects of dietary nitrates and nitrites. Current regulatory limits on nitrate intakes, based on concerns regarding potential risk of carcinogenicity and methemoglobinemia, are exceeded by normal daily intakes of single foods, such as soya milk and spinach, as well as by some recommended dietary patterns such as the Dietary Approaches to Stop Hypertension diet. This review includes a call for regulatory bodies to consider all available data on the beneficial physiologic roles of nitrate and nitrite in order to derive rational bases for dietary recommendations.

  20. Radiation-induced radical ions in calcium sulfite

    Science.gov (United States)

    Bogushevich, S. E.

    2006-07-01

    We have used EPR to study the effect of γ radiation on calcium sulfite. We have observed and identified the radiation-induced radical ions SO 2 - (iso) with g = 2.0055 and SO 2 - (orth-1) with g1 = 2.0093, g2 = 2.0051, g3 = 2.0020, identical to the initial and thermally induced SO 2 - respectively, SO 3 - (iso) with g = 2.0031 and SO 3 - (axial) with g⊥ = 2.0040, g∥ = 2.0023, identical to mechanically induced SO 3 - . We have established the participation of radiation-induced radical ions SO 3 - in formation of post-radiation SO 2 - .

  1. Platelet inhibition by nitrite is dependent on erythrocytes and deoxygenation.

    Directory of Open Access Journals (Sweden)

    Sirada Srihirun

    Full Text Available Nitrite is a nitric oxide (NO metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet activity was investigated.Platelet aggregation was studied in platelet-rich plasma (PRP and PRP+erythrocytes by turbidimetric and impedance aggregometry, respectively. In PRP, DEANONOate inhibited platelet aggregation induced by ADP while nitrite had no effect on platelets. In PRP+erythrocytes, the inhibitory effect of DEANONOate on platelets decreased whereas nitrite at physiologic concentration (0.1 µM inhibited platelet aggregation and ATP release. The effect of nitrite+erythrocytes on platelets was abrogated by C-PTIO (a membrane-impermeable NO scavenger, suggesting an NO-mediated action. Furthermore, deoxygenation enhanced the effect of nitrite as observed from a decrease of P-selectin expression and increase of the cGMP levels in platelets. The ADP-induced platelet aggregation in whole blood showed inverse correlations with the nitrite levels in whole blood and erythrocytes.Nitrite alone at physiological levels has no effect on platelets in plasma. Nitrite in the presence of erythrocytes inhibits platelets through its reduction to NO, which is promoted by deoxygenation. Nitrite may have role in modulating platelet activity in the circulation, especially during hypoxia.

  2. A comparison of organic and inorganic nitrates/nitrites.

    Science.gov (United States)

    Omar, Sami A; Artime, Esther; Webb, Andrew J

    2012-05-15

    Although both organic and inorganic nitrates/nitrites mediate their principal effects via nitric oxide, there are many important differences. Inorganic nitrate and nitrite have simple ionic structures and are produced endogenously and are present in the diet, whereas their organic counterparts are far more complex, and, with the exception of ethyl nitrite, are all medicinally synthesised products. These chemical differences underlie the differences in pharmacokinetic properties allowing for different modalities of administration, particularly of organic nitrates, due to the differences in their bioavailability and metabolic profiles. Whilst the enterosalivary circulation is a key pathway for orally ingested inorganic nitrate, preventing an abrupt effect or toxic levels of nitrite and prolonging the effects, this is not used by organic nitrates. The pharmacodynamic differences are even greater; while organic nitrates have potent acute effects causing vasodilation, inorganic nitrite's effects are more subtle and dependent on certain conditions. However, in chronic use, organic nitrates are considerably limited by the development of tolerance and endothelial dysfunction, whereas inorganic nitrate/nitrite may compensate for diminished endothelial function, and tolerance has not been reported. Also, while inorganic nitrate/nitrite has important cytoprotective effects against ischaemia-reperfusion injury, continuous use of organic nitrates may increase injury. While there are concerns that inorganic nitrate/nitrite may induce carcinogenesis, direct evidence of this in humans is lacking. While organic nitrates may continue to dominate the therapeutic arena, this may well change with the increasing recognition of their limitations, and ongoing discovery of beneficial effects and specific advantages of inorganic nitrate/nitrite. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. MRP-1 and BCRP Promote the Externalization of Phosphatidylserine in Oxalate-treated Renal Epithelial Cells: Implications for Calcium Oxalate Urolithiasis.

    Science.gov (United States)

    Li, YiFu; Yu, ShiLiang; Gan, XiuGuo; Zhang, Ze; Wang, Yan; Wang, YingWei; An, RuiHua

    2017-09-01

    To investigate the possible involvement of multidrug resistance-associated protein 1 (MRP-1) and breast cancer resistance protein (BCRP) in the oxalate-induced redistribution of phosphatidylserine (PS) in renal epithelial cell membranes. A western blot analysis was used to examine the MRP-1 and BCRP expression levels. Surface-expressed PS was detected by the annexin V-binding assay. The cell-permeable fluorogenic probe 2,7-dichlorofluorescein diacetate was used to measure the intracellular reactive oxygen species (ROS) level. A rat model of hyperoxaluria was obtained using 0.5% ethylene glycol and 1.0% ammonium chloride. In addition, certain animals received verapamil (50 mg/kg body weight), which is a common inhibitor of MRP-1 and BCRP. The degree of nephrolithiasis was assessed histomorphometrically using sections stained by Pizzolato method and by measuring the calcium oxalate crystal content in the renal tissue. Oxalate produced a concentration-dependent increase in the synthesis of MRP-1 and BCRP. Treatment with MK571 and Ko143 (MRP-1- and BCRP-specific inhibitors, respectively) significantly attenuated the oxalate-induced PS externalization. Adding the antioxidant N-acetyl-l-cysteine significantly reduced MRP-1 and BCRP expression. In vivo, markedly decreased nephrocalcinosis was observed compared with that in the rat model of hyperoxaluria without verapamil treatment. Oxalate induces the upregulation of MRP-1 and BCRP, which act as phospholipid floppases causing PS externalization in the renal epithelial cell membrane. The process is mediated by intracellular ROS production. The ROS-mediated increase in the synthesis of MRP-1 and BCRP can play an important role in hyperoxaluria-promoted calcium oxalate urolithiasis by facilitating phosphatidylserine redistribution in renal epithelial cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Putative Aspergillus niger-induced oxalate nephrosis in sheep : clinical communication

    Directory of Open Access Journals (Sweden)

    C.J. Botha

    2009-05-01

    Full Text Available A sheep farmer provided a maize-based brewer's grain (mieliemaroek and bales of Eragrostis curvula hay to ewes and their lambs, kept on zero-grazing in pens. The 'mieliemaroek' was visibly mouldy. After 14 days in the feedlot, clinical signs, including generalised weakness, ataxia of the hind limbs, tremors and recumbency, were noticed. Six ewes died within a period of 7 days. A post mortem examination was performed on 1 ewe. The carcass appeared to be cachectic with mild effusions into the body cavities; mild lung congestion and pallor of the kidneys were observed. Microscopical evaluation revealed nephrosis and birefringent oxalate crystals in the renal tubules when viewed under polarised light. A provisional diagnosis of oxalate nephrosis with subsequent kidney failure was made. Amongst other fungi, Aspergillus niger was isolated from 'mieliemaroek' samples submitted for fungal culture and identification. As A. niger is known to synthesise oxalates, a qualitative screen to detect oxalic acid in the mieliemaroek and purified A. niger isolates was performed using high-performance liquid chromatography (HPLC. Oxalic acid was detected, which supported a diagnosis of soluble oxalate-induced nephropathy.

  5. Evidence for a cytoplasmic pathway of oxalate biosynthesis in Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Kubicek, C.P.; Schreferl-Kunar, G.; Woehrer, W.; Roehr, M.

    1988-03-01

    Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of P/sub i/ and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added /sup 14/CO/sub 2/ was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle.

  6. Morphological control of strontium oxalate particles by PSMA-mediated precipitation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Yu Jiaguo [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)]. E-mail: jiaguoyu@yahoo.com; Tang Hua [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Cheng Bei [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

    2005-05-15

    In this paper, strontium oxalate particles with different morphologies could be easily obtained by a precipitation reaction of sodium oxalate with strontium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA). The as-prepared products were characterized with scanning electron microscopy and X-ray diffraction. The effects of pH, aging time and concentration of PSMA on the phase structures and morphologies of the as-prepared strontium oxalate particles were investigated and discussed. The results showed that strontium oxalate particles with various morphologies, such as, bi-pyramids, rods, peanuts, and spherical particles, etc., could be obtained by varying the experimental conditions. PSMA promoted the formation of strontium oxalate dihydrate (SOD) phase. Suitable pH values (pH 7 and 8) favor the formation of the peanut-shaped SrC{sub 2}O{sub 4} particles. This research may provide new insight into the control of morphologies and phase structures of strontium oxalate particles and the biomimetic synthesis of novel inorganic materials.

  7. The metabolic and ecological interactions of oxalate-degrading bacteria in the Mammalian gut.

    Science.gov (United States)

    Miller, Aaron W; Dearing, Denise

    2013-12-06

    Oxalate-degrading bacteria comprise a functional group of microorganisms, commonly found in the gastrointestinal tract of mammals. Oxalate is a plant secondary compound (PSC) widely produced by all major taxa of plants and as a terminal metabolite by the mammalian liver. As a toxin, oxalate can have a significant impact on the health of mammals, including humans. Mammals do not have the enzymes required to metabolize oxalate and rely on their gut microbiota for this function. Thus, significant metabolic interactions between the mammalian host and a complex gut microbiota maintain the balance of oxalate in the body. Over a dozen species of gut bacteria are now known to degrade oxalate. This review focuses on the host-microbe and microbe-microbe interactions that regulate the degradation of oxalate by the gut microbiota. We discuss the pathways of oxalate throughout the body and the mammalian gut as a series of differentiated ecosystems that facilitate oxalate degradation. We also explore the mechanisms and functions of microbial oxalate degradation along with the implications for the ecological and evolutionary interactions within the microbiota and for mammalian hosts. Throughout, we consider questions that remain, as well as recent technological advances that can be employed to answer them.

  8. Removal of sulfite liquor from digesters with partially diluted liquor

    Energy Technology Data Exchange (ETDEWEB)

    Leshchenko, I G; Sykol, V P

    1957-01-01

    The yield of reducing sugars was raised from 189 to 224 kg/ton of pulp by displacing the cooking liquor with diluted liquor. As the pressure during blow-off dropped to 3.5-3.0 atmosphere, weak sulfite liquor was added at the rate 120 cu m/hr. After 5-10 minutes the liquor was pumped from the digester to the ethanol plant.

  9. Biorefinery lignosulfonates from sulfite-pretreated softwoods as dispersant for graphite

    Science.gov (United States)

    Yanlin Qin; Lixuan Yu; Ruchun Wu; Dongjie Yang; Xueqing Qiu; Junyong Zhu

    2016-01-01

    Two biorefinery lignosulfonates (LSs), Ca-LS-DF and Na-LS-LP were, respectively, isolated from pilot-scale sulfite-pretreated spent liquor of lodgepole pine and fermentation residue of Douglas-fir harvest forest residue. The molecular weights of Na-LS-LP and Ca-LS-DF were approximately 9 000 and 11 000 Da, respectively. The two LSs were applied as dispersant for...

  10. Differential uptake and metabolism of nitrite in normoxic and hypoxic goldfish

    DEFF Research Database (Denmark)

    Jensen, Frank Bo; Hansen, Marie N.

    2011-01-01

    extracellular and intracellular compartments, revealing nitrosative stress with extensive nitros(yl)ation of thiols, amines and heme groups. The degree of nitrosative stress correlated with nitrite load. Nitrate levels increased in all compartments, reflecting that a significant fraction of the nitrite taken up...... was converted to non-toxic nitrate. The generation of methemoglobin and nitrosylhemoglobin (assessed by spectral deconvolution) was more pronounced during normoxic nitrite exposure than during hypoxic nitrite exposure, in agreement with the higher nitrite load in normoxic fish. However, at any given nitrite......Nitrite is a physiological important nitric oxide donor at low concentrations but becomes toxic at high concentrations, as develops in freshwater fish exposed to environmental nitrite. We hypothesized that nitrite uptake across the gills differs between normoxic and hypoxic fish and that nitrite...

  11. Two-stage precipitation of neptunium (IV) oxalate

    International Nuclear Information System (INIS)

    Luerkens, D.W.

    1983-07-01

    Neptunium (IV) oxalate was precipitated using a two-stage precipitation system. A series of precipitation experiments was used to identify the significant process variables affecting precipitate characteristics. Process variables tested were input concentrations, solubility conditions in the first stage precipitator, precipitation temperatures, and residence time in the first stage precipitator. A procedure has been demonstrated that produces neptunium (IV) oxalate particles that filter well and readily calcine to the oxide

  12. Preparation, characterization and catalytic effects of copper oxalate nanocrystals

    International Nuclear Information System (INIS)

    Singh, Gurdip; Kapoor, Inder Pal Singh; Dubey, Reena; Srivastava, Pratibha

    2012-01-01

    Graphical abstract: Prepared copper oxalate nanocrystals were characterized by FE-SEM and bright field TEM micrographs. Its catalytic activity was evaluated on the thermal decomposition of ammonium perchlorate using TG and TG-DSC techniques. Highlights: ► Preparation of nanocrystals (∼9.0 nm) of copper oxalate using Cu(NO 3 ) 2 ·2H 2 O, oxalic acid and acetone under thermal conditions. ► Method is simple and novel. ► Characterization using XRD, SEM, TEM, HRTEM and ED pattern. ► Catalytic activity of copper oxalate nanocrystals on AP thermal decomposition using thermal techniques (TG, TG-DSC and ignition delay). ► Kinetics of thermal decomposition of AP + CONs using isoconversional and model fitting kinetic approaches. - Abstract: Recent work has described the preparation and characterization of copper oxalate nanocrystals (CONs). It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and electron diffraction pattern (ED). The catalytic activity of CONs on the thermal decomposition of ammonium perchlorate (AP) and composite solid propellants (CSPs) has been done by thermogravimetry (TG), differential scanning calorimetry (DSC) and ignition delay measurements. Burning rate of CSPs was also found to be enhanced in presence of copper oxalate nanocrystals. Kinetics of thermal decomposition of AP with and without CONs has also been investigated. The model free (isoconversional) and model-fitting kinetic approaches have been applied to data for isothermal TG decomposition.

  13. Intermediates detected by visible spectroscopy during the reaction of nitrite with deoxyhemoglobin: the effect of nitrite concentration and diphosphoglycerate.

    Science.gov (United States)

    Nagababu, Enika; Ramasamy, Somasundaram; Rifkind, Joseph M

    2007-10-16

    The reaction of nitrite with deoxyhemoglobin (deoxyHb) results in the reduction of nitrite to NO, which binds unreacted deoxyHb forming Fe(II)-nitrosylhemoglobin (Hb(II)NO). The tight binding of NO to deoxyHb is, however, inconsistent with reports implicating this reaction with hypoxic vasodilation. This dilemma is resolved by the demonstration that metastable intermediates are formed in the course of the reaction of nitrite with deoxyHb. The level of intermediates is quantitated by the excess deoxyHb consumed over the concentrations of the final products formed. The dominant intermediate has a spectrum that does not correspond to that of Hb(III)NO formed when NO reacts with methemoglobin (MetHb), but is similar to metHb resulting in the spectroscopic determinations of elevated levels of metHb. It is a delocalized species involving the heme iron, the NO, and perhaps the beta-93 thiol. The putative role for red cell reacted nitrite on vasodilation is associated with reactions involving the intermediate. (1) The intermediate is less stable with a 10-fold excess of nitrite and is not detected with a 100-fold excess of nitrite. This observation is attributed to the reaction of nitrite with the intermediate producing N2O3. (2) The release of NO quantitated by the formation of Hb(II)NO is regulated by changes in the distal heme pocket as shown by the 4.5-fold decrease in the rate constant in the presence of 2,3-diphosphoglycerate. The regulated release of NO or N2O3 as well as the formation of the S-nitroso derivative of hemoglobin, which has also been reported to be formed from the intermediates generated during nitrite reduction, should be associated with any hypoxic vasodilation attributed to the RBC.

  14. Features of atopic dermatitis in children with oxalic acid dysmetabolism

    Directory of Open Access Journals (Sweden)

    T.V. Stoieva

    2018-03-01

    Full Text Available The article presents the features of atopic dermatitis in children with concomitant metabolic disturbances of oxalic acid. The influence of metabolic shifts was evaluated by clinical presentation, morphofunctional parameters of the skin and the features of oxalic acid metabolites excretion. In this study, a high incidence of dysmetabolic changes was identified, their significance was determined by the involvement of different systems for oxalic acid products excretion. The increased concentration of oxalate in the urine and in the exhaled air condensate had irritant effect and is associated with the hereditary metabolic disorders, early manifestation of atopy symptoms and the intensity of skin itching, with moderate increase of immunoglobulin E level.

  15. Novel Inorganic Coordination Polymers Based on Cadmium Oxalates

    Science.gov (United States)

    Prasad, P. A.; Neeraj, S.; Vaidhyanathan, R.; Natarajan, Srinivasan

    2002-06-01

    Three new cadmium oxalate coordination polymers, I-III, with extended layered structures have been synthesized in the presence of imidazole. While I was prepared by the reaction between imidazolium oxalate and Cd, II and III were synthesized from their constituents using hydrothermal methods. [Cd(C2O4)(C3N2H4)]∞ (I): monoclinic, space group P21/c (no. 14), a=8.7093(1) Å, b=9.9477(3) Å, c=8.4352 Å, β=93.796(1)°, Z=4; [Cd(C2O4)2(C3N2H4)3(H2O)]∞ (II): monoclinic, space group P21/c (no. 14), a=7.8614(2) Å, b=14.9332(3) Å, c=15.9153(4) Å β=94.587(1)°, Z=4; [Cd(C2O4)2(C3N2H4)3(H2O)]∞ (III): monoclinic, space group P21/c (no. 14), a=11.844(2) Å, b=9.066(1) Å, c=18.583(2) Å, β=103.84(2)°, Z=4. While the structure of I is made from CdO5N distorted octahedra linked with oxalate, II and III are built-up from CdO6N, CdO5N2 distorted pentagonal bi-pyramids connected to oxalate units. The framework formulas of II and III are identical and their structures closely related. In all the cases, the networking between the Cd-O/N polyhedra and oxalates give rise to layered architectures with the amine molecules pointing in a direction perpendicular to the layers (in the inter-lamellar region). The difference in the linkages between the oxalates and the Cd atoms in I-III, produces unusual Cd-O-Cd one-dimensional chains, which have been observed for the first time.

  16. Respiration of Nitrate and Nitrite.

    Science.gov (United States)

    Cole, Jeffrey A; Richardson, David J

    2008-09-01

    Nitrate reduction to ammonia via nitrite occurs widely as an anabolic process through which bacteria, archaea, and plants can assimilate nitrate into cellular biomass. Escherichia coli and related enteric bacteria can couple the eight-electron reduction of nitrate to ammonium to growth by coupling the nitrate and nitrite reductases involved to energy-conserving respiratory electron transport systems. In global terms, the respiratory reduction of nitrate to ammonium dominates nitrate and nitrite reduction in many electron-rich environments such as anoxic marine sediments and sulfide-rich thermal vents, the human gastrointestinal tract, and the bodies of warm-blooded animals. This review reviews the regulation and enzymology of this process in E. coli and, where relevant detail is available, also in Salmonella and draws comparisons with and implications for the process in other bacteria where it is pertinent to do so. Fatty acids may be present in high levels in many of the natural environments of E. coli and Salmonella in which oxygen is limited but nitrate is available to support respiration. In E. coli, nitrate reduction in the periplasm involves the products of two seven-gene operons, napFDAGHBC, encoding the periplasmic nitrate reductase, and nrfABCDEFG, encoding the periplasmic nitrite reductase. No bacterium has yet been shown to couple a periplasmic nitrate reductase solely to the cytoplasmic nitrite reductase NirB. The cytoplasmic pathway for nitrate reduction to ammonia is restricted almost exclusively to a few groups of facultative anaerobic bacteria that encounter high concentrations of environmental nitrate.

  17. The role of nitrite in nitric oxide homeostasis

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2009-01-01

    Nitrite is endogenously produced as an oxidative metabolite of nitric oxide, but it also functions as a NO donor that can be activated by a number of cellular proteins under hypoxic conditions. This article discusses the physiological role of nitrite and nitrite-derived NO in blood flow regulation...... mechanisms. Nitrite reduction to NO provides cytoprotection in tissues during ischemia-reperfusion events by inhibiting mitochondrial respiration and limiting reactive oxygen species. It is argued that the study of hypoxia-tolerant lower vertebrates and diving mammals may help evaluate mechanisms and a full...

  18. Total, Soluble and Insoluble Oxalate Contents of Ripe Green and Golden Kiwifruit.

    Science.gov (United States)

    Nguyễn, Hà Vũ Hồng; Savage, Geoffrey P

    2013-03-05

    Three bulk samples of two different cultivars of kiwifruit, green ( Actinidia deliciosa L . ) and golden ( Actinidia chinensis L . ) were bought ripe, ready to eat from a local market. The aim of the study was to determine the oxalate composition of each of the three fractions of kiwifruit, namely skin, pulp and seeds. The pulp consisted of 90.4% of the edible portion of the two cultivars while the skin and seeds made up a mean of 8.0% and 1.6% respectively. Total oxalate was extracted with 2.0 M HCL at 21 °C for 15 min and soluble oxalates extracted at 21 °C in water for 15 min from each fraction. The total and soluble oxalate compositions of each fraction were determined using ion exchange HPLC chromatography. The pulp of golden kiwifruit contained lower amounts of total oxalates (15.7 vs. 19.3 mg/100 g FW) and higher amounts of soluble oxalates (8.5 vs. 7.6 mg/100 g FW) when compared to the green cultivar. The skin of the green cultivar contained lower levels of insoluble oxalates (36.9 vs. 43.6 mg/100 g FW), while the seeds of the green cultivar contained higher levels of insoluble oxalates 106.7 vs. 84.7 mg/100 g FW.

  19. A random-sequential mechanism for nitrite binding and active site reduction in copper-containing nitrite reductase

    NARCIS (Netherlands)

    Wijma, HJ; Jeuken, LJC; Verbeet, MP; Armstrong, FA; Canters, GW

    2006-01-01

    The homotrimeric copper-containing nitrite reductase ( NiR) contains one type-1 and one type-2 copper center per monomer. Electrons enter through the type-1 site and are shuttled to the type-2 site where nitrite is reduced to nitric oxide. To investigate the catalytic mechanism of NiR the effects of

  20. Urinary oxalate excretion, as determined by isotope dilution and indirect colorimetry

    International Nuclear Information System (INIS)

    Prenen, J.A.C.; Boer, P.; Leersum, L. van; Oldenburg, S.J.; Endeman, H.J.

    1983-01-01

    A simple and reliable method for the determination of urinary oxalate excretion is described. Urinary oxalate is precipitated with calcium chloride, and the oxalate content of the precipitate is measured by an indirect colorimetric method developed by Neas and Guyon in 1972. For single urine samples, a correction is made for the incompleteness of the precipitation of calcium oxalate by isotope dilution. The range of normal values (5% limits) determined in 52 normal subjects was 0.121-0.325 mmol.24 h - 1 .m - 2 for a 1-day collection period and 0.145-0.301 mmol. 24 h - 1 .m - 2 for a 3-day collection period. The within-assay CV of a control urine with a low oxalate concentration was 9% (n=7) and the between-assay CV for the same control urine was 12% (n=6). When the values obtained for oxalate excretion were normalized to body surface area, there was no significant difference between males and females; the main source of variation was the intra-individual variation. (Auth.)

  1. Availability of calcium from chemically pure potassium oxalate to the buffalo (Bubalus bubalis)

    International Nuclear Information System (INIS)

    Singh, Sudarshan; Sareen, V.K.; Marwah, S.R.; Sharma, K.C.; Bhatia, I.S.

    1978-01-01

    Three experiments were conducted to determine the true dige'stibility of calcium in the buffalo calves fed chemically pure potassium oxalate. In each experiments 6 calves were divided into two groups, viz. control and oxalate-fed. The control group was given basal ration consisting of wheat straw, mustard-cake and maize grains. The oxalate-fed group was fed the basal ration supplemented with 60, 100 and 140 g potassium oxalate per day in experiments 1,2, and 3 respectively. The percent true digestibility of calcium was 51.7 and 52.5 in experiment 1, 60.5 and 44.1 in experiment 2, and 59.3 and 44.1 in experiment 3 in the control and oxalate-fed groups respectively. In all the experiments the oxalate was completely broken down in the rumen. The volume of water intake and urine excretion was more in the oxalate-fed groups. The daily alkali output in the urine in terms of N-acid was 0.7 and 1.3 in experiment 1, 1.5 and 2.5 in experiment 2, and 2.1 and 3.8 in experiment 3 in control and oxalate-fed groups respectively. The daily bicarbonate concentration in the urine (in g) was 26.5 and 53.4 in experiment 1, 83.2 and 146.2 in experiment 2, and 132.6 and 222.8 in experiment 3 in control and oxalate-fed groups respectively. Likewise the excretion of oxalate in the urine was more in oxalate-fed groups. On the basis of the results obtained, the reason for the somewhat low true digestibility of calcium in the calves consuming more than 60 g of potassium oxalate/day are discussed. Isotope-dilution technique using 45 CaCl 2 was employed in the study. (auth.)

  2. Hydrothermal synthesis of uranyl squarates and squarate-oxalates: hydrolysis trends and in situ oxalate formation.

    Science.gov (United States)

    Rowland, Clare E; Cahill, Christopher L

    2010-07-19

    We report the synthesis of two uranyl squarates and two mixed-ligand uranyl squarate-oxalates from aqueous solutions under hydrothermal conditions. These products exhibit a range of uranyl building units from squarates with monomers in (UO(2))(2)(C(4)O(4))(5).6NH(4).4H(2)O (1; a = 16.731(17) A, b = 7.280(8) A, c = 15.872(16) A, beta = 113.294(16) degrees , monoclinic, P2(1)/c) and chains in (UO(2))(2)(OH)(2)(H(2)O)(2)(C(4)O(4)) (2; a = 12.909(5) A, b = 8.400(3) A, c = 10.322(4) A, beta = 100.056(7) degrees , monoclinic, C2/c) to two squarate-oxalate polymorphs with dimers in (UO(2))(2)(OH)(C(4)O(4))(C(2)O(4)).NH(4).H(2)O (3; a = 9.0601(7) A, b = 15.7299(12) A, c = 10.5108(8) A, beta = 106.394(1) degrees , monoclinic, P2(1)/n; and 4; a = 8.4469(6) A, b = 7.7589(5) A, c = 10.5257(7) A, beta = 105.696(1) degrees , monoclinic, P2(1)/m). The dominance at low pH of monomeric species and the increasing occurrence of oligomeric species with increasing pH suggests that uranyl hydrolysis, mUO(2)(2+) + nH(2)O right harpoon over left harpoon [(UO(2))(m)(OH)(n)](2m-n) + nH(+), has a significant role in the identity of the inorganic building unit. Additional factors that influence product assembly include in situ hydrolysis of squaric acid to oxalic acid, dynamic metal to ligand concentration, and additional binding modes resulting from the introduction of oxalate anions. These points and the effects of uranyl hydrolysis with changing pH are discussed in the context of the compounds presented herein.

  3. Unusual calcium oxalate crystals in ethylene glycol poisoning.

    Science.gov (United States)

    Godolphin, W; Meagher, E P; Sanders, H D; Frohlich, J

    1980-06-01

    A patient poisoned with ethylene glycol exhibited the symptoms of (1) hysteria, (2) metabolic acidosis with both a large anion gap and osmolal gap, and (3) crystalluria. However, the shape of the urinary crystals was prismatic and resembled hippurate rather than the expected dipyramidal calcium oxalate dihydrate. X-ray crystallography positively identified them as calcium oxalate monohydrate.

  4. Crystallization of calcium oxalate in minimally diluted urine

    Science.gov (United States)

    Bretherton, T.; Rodgers, A.

    1998-09-01

    Crystallization of calcium oxalate was studied in minimally diluted (92%) urine using a mixed suspension mixed product crystallizer in series with a Malvern particle sizer. The crystallization was initiated by constant flow of aqueous sodium oxalate and urine into the reaction vessel via two independent feed lines. Because the Malvern cell was in series with the reaction vessel, noninvasive measurement of particle sizes could be effected. In addition, aliquots of the mixed suspension were withdrawn and transferred to a Coulter counter for crystal counting and sizing. Steady-state particle size distributions were used to determine nucleation and growth kinetics while scanning electron microscopy was used to examine deposited crystals. Two sets of experiments were performed. In the first, the effect of the concentration of the exogenous sodium oxalate was investigated while in the second, the effect of temperature was studied. Calcium oxalate nucleation and growth rates were found to be dependent on supersaturation levels inside the crystallizer. However, while growth rate increased with increasing temperature, nucleation rates decreased. The favored phases were the trihydrate at 18°C, the dihydrate at 38° and the monohydrate at 58°C. The results of both experiments are in agreement with those obtained in other studies that have been conducted in synthetic and in maximally diluted urine and which have employed invasive crystal counting and sizing techniques. As such, the present study lends confidence to the models of urinary calcium oxalate crystallization processes which currently prevail in the literature.

  5. Protective role of curcumin against sulfite-induced structural changes in rats' medial prefrontal cortex.

    Science.gov (United States)

    Noorafshan, Ali; Asadi-Golshan, Reza; Abdollahifar, Mohammad-Amin; Karbalay-Doust, Saied

    2015-08-01

    Sodium metabisulfite as a food preservative can affect the central nervous system. Curcumin, the main ingredient of turmeric has neuroprotective activity. This study was designed to evaluate the effects of sulfite and curcumin on the medial prefrontal cortex (mPFC) using stereological methods. Thirty rats were randomly divided into five groups. The rats in groups I-V received distilled water, olive oil, curcumin (100 mg/kg/day), sodium metabisulfite (25 mg/kg/day), and sulfite + curcumin, respectively, for 8 weeks. The brains were subjected to the stereological methods. Cavalieri and optical disector techniques were used to estimate the total volume of mPFC and the number of neurons and glial cells. Intersections counting were applied on the thick vertical uniform random sections to estimate the dendrites length, and classify the spines. Non-parametric tests were used to analyze the data. The mean mPFC volume, neurons number, glia number, dendritic length, and total spines per neuron were 3.7 mm(3), 365,000, 180,000, 1820 µm, and 1700 in distilled water group, respectively. A reduction was observed in the volume of mPFC (∼8%), number of neurons (∼15%), and number of glia (∼14%) in mPFC of the sulfite group compared to the control groups (P curcumin had a protective role against the changes in the rats.

  6. Heterogeneous nucleation of calcium oxalate on native oxide surfaces

    International Nuclear Information System (INIS)

    Song, L.; Pattillo, M.J.; Graff, G.L.; Campbell, A.A.; Bunker, B.C.

    1994-04-01

    The aqueous deposition of calcium oxalate onto colloidal oxides has been studied as a model system for understanding heterogeneous nucleation processes of importance in biomimetic synthesis of ceramic thin films. Calcium oxalate nucleation has been monitored by measuring induction times for nucleation using Constant Composition techniques and by measuring nucleation densities on extended oxide surfaces using an atomic force microscope. Results show that the dependence of calcium oxalate nucleation on solution supersaturation fits the functional form predicted by classical nucleation theories. Anionic surfaces appear to promote nucleation better than cationic surfaces, lowering the effective energy barrier to heterogeneous nucleation

  7. KINETICS OF POLYMERIZATION OF METHYL METHACRYLATE INITIATED BY COPPER POLYPROPYLENE-BASED POLYAMIDOXIME-SODIUM SULFITE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    WU Jinyuan; YANG Yiguang; YANG Chaoxiong

    1992-01-01

    The aqueous polymerization of methyl methacrylate initiated by copper polypropylene-based polyamidoxime ( PPAO - Cu ) - sodium sulfite system was investigated . The overall rate of polymerization (Rp) is Rp=9.7 × 1012 e-21, 200/RT [MMA]0.88 [ Na2 SO 3 ]0.50 The length of the induction period (τ) is inversely proportional to the concentration of sodium sulfite and independent of the amount of polymer supported copper and the concentration of monomer. It could be expressed as follows:1τ=1.2× 1012e-15,600/RT[ Na2SO3] =KτRi The polymerization is initiated by a primary radical generated from the redox reaction rather than induced by "coordination-proton transfer" mechanism.

  8. Total, Soluble and Insoluble Oxalate Contents of Ripe Green and Golden Kiwifruit

    Directory of Open Access Journals (Sweden)

    Hà Vũ Hồng Nguyễn

    2013-03-01

    Full Text Available Three bulk samples of two different cultivars of kiwifruit, green (Actinidia deliciosa L. and golden (Actinidia chinensis L. were bought ripe, ready to eat from a local market. The aim of the study was to determine the oxalate composition of each of the three fractions of kiwifruit, namely skin, pulp and seeds. The pulp consisted of 90.4% of the edible portion of the two cultivars while the skin and seeds made up a mean of 8.0% and 1.6% respectively. Total oxalate was extracted with 2.0 M HCL at 21 °C for 15 min and soluble oxalates extracted at 21 °C in water for 15 min from each fraction. The total and soluble oxalate compositions of each fraction were determined using ion exchange HPLC chromatography. The pulp of golden kiwifruit contained lower amounts of total oxalates (15.7 vs. 19.3 mg/100 g FW and higher amounts of soluble oxalates (8.5 vs. 7.6 mg/100 g FW when compared to the green cultivar. The skin of the green cultivar contained lower levels of insoluble oxalates (36.9 vs. 43.6 mg/100 g FW, while the seeds of the green cultivar contained higher levels of insoluble oxalates 106.7 vs. 84.7 mg/100 g FW.

  9. Correlation between oxalic acid production and copper tolerance in Wolfiporia cocos

    Science.gov (United States)

    C. A. Clausen; Frederick Green; B. M. Woodward; J. W. Evans; R. C. DeGroot

    2000-01-01

    The increased interest in copper-based wood preservatives has hastened the need for understanding why some fungi are able to attack copper-treated wood. Due in part to accumulation of oxalic acid by brown-rot fungi and visualization of copper oxalate crystals in wood decayed by known copper-tolerant decay fungi, oxalic acid has been implicated in copper tolerance by...

  10. Stable-isotope dilution GC-MS approach for nitrite quantification in human whole blood, erythrocytes, and plasma using pentafluorobenzyl bromide derivatization: nitrite distribution in human blood.

    Science.gov (United States)

    Schwarz, Alexandra; Modun, Darko; Heusser, Karsten; Tank, Jens; Gutzki, Frank-Mathias; Mitschke, Anja; Jordan, Jens; Tsikas, Dimitrios

    2011-05-15

    Previously, we reported on the usefulness of pentafluorobenzyl bromide (PFB-Br) for the simultaneous derivatization and quantitative determination of nitrite and nitrate in various biological fluids by GC-MS using their (15)N-labelled analogues as internal standards. As nitrite may be distributed unevenly in plasma and blood cells, its quantification in whole blood rather than in plasma or serum may be the most appropriate approach to determine nitrite concentration in the circulation. So far, GC-MS methods based on PFB-Br derivatization failed to measure nitrite in whole blood and erythrocytes because of rapid nitrite loss by oxidation and other unknown reactions during derivatization. The present article reports optimized and validated procedures for sample preparation and nitrite derivatization which allow for reliable quantification of nitrite in human whole blood and erythrocytes. Essential measures for stabilizing nitrite in these samples include sample cooling (0-4°C), hemoglobin (Hb) removal by precipitation with acetone and short derivatization of the Hb-free supernatant (5 min, 50°C). Potassium ferricyanide (K(3)Fe(CN)(6)) is useful in preventing Hb-caused nitrite loss, however, this chemical is not absolutely required in the present method. Our results show that accurate GC-MS quantification of nitrite as PFB derivative is feasible virtually in every biological matrix with similar accuracy and precision. In EDTA-anticoagulated venous blood of 10 healthy young volunteers, endogenous nitrite concentration was measured to be 486±280 nM in whole blood, 672±496 nM in plasma (C(P)), and 620±350 nM in erythrocytes (C(E)). The C(E)-to-C(P) ratio was 0.993±0.188 indicating almost even distribution of endogenous nitrite between plasma and erythrocytes. By contrast, the major fraction of nitrite added to whole blood remained in plasma. The present GC-MS method is useful to investigate distribution and metabolism of endogenous and exogenous nitrite in blood

  11. Nitrates, Nitrites, and Health. Bulletin 750.

    Science.gov (United States)

    Deeb, Barbara S.; Sloan, Kenneth W.

    This review is intended to assess available literature in order to define the range of nitrate/nitrite effects on animals. Though the literature deals primarily with livestock and experimental animals, much of the contemporary research is concerned with human nitrite intoxication. Thus, the effects on man are discussed where appropriate. Some of…

  12. Effects of Juice Processing on Oxalate Contents in Carambola Juice Products.

    Science.gov (United States)

    Huynh, Nha K; Nguyen, Ha V H

    2017-09-01

    Effects of processing methods including pressing, enzyme-assisted extraction, lactic acid fermentation by Lactobacillus acidophilus, and alcohol fermentation by Saccharomyces cerevisiae on total and soluble oxalate contents of carambola juices were studied. In comparison with pressing, the use of enzyme increased juice yields (15.89-17.29%), but resulted in higher total oxalate (1.60-1.73 times) and soluble oxalate contents (1.16-1.49 times). In addition, extension of enzyme incubation periods led to an increase in soluble oxalate contents in the products (p carambola juices. These results suggested that carambola juice products should only be consumed moderately, and that alcohol fermentation could be a potential method to reduce oxalate contents in foods in order to prevent the risks of forming kidney stones.

  13. Reaction of Hydrazine Hydrate with Oxalic Acid: Synthesis and ...

    African Journals Online (AJOL)

    NICO

    2013-11-28

    Nov 28, 2013 ... The title compound is a molecular salt containing two discrete hydrazinium cations and an oxalate anion. The oxalate ... RESEARCH ARTICLE ... Scheme and reaction showing the simple experimental procedure for the preparation of .... 7 A.I. Vogel, A Text Book of Quantitative Inorganic Analysis, 4th edn.,.

  14. Studies on the decomposition of oxalic acid by nitric acid in presence of catalysts

    International Nuclear Information System (INIS)

    Noronha, D.M.; Pius, I.C.; Chaudhury, S.

    2015-01-01

    Impure Plutonium oxalate generated from the recovery of plutonium from waste solutions may require further purification via anion exchange. Conventionally, plutonium oxalate is converted to oxide in a furnace and the oxide is dissolved in Conc. HNO 3 containing HF and purified by anion exchange route. Studies initiated on the decomposition of oxalic acid with Conc. HNO 3 to facilitate direct dissolution of plutonium oxalate and quantitative destruction of oxalate are discussed in this paper. (author)

  15. Optimization of precipitation conditions of thorium oxalate precipitate

    International Nuclear Information System (INIS)

    Pazukhin, Eh.M.; Smirnova, E.A.; Krivokhatskij, A.S.; Pazukhina, Yu.L.; Kiselev, P.P.

    1986-01-01

    Thorium precipitation in the form of difficultly soluble oxalate has been investigated. The equation binding the concentration of metal with the nitric acid in the initial solution and quantity of a precipitator necessary for minimization of desired product losses is derived. The graphical solution of this equation for a case, when the oxalic acid with 0.78 mol/l concentration is the precipitator, is presented

  16. Modification of membrane sulfhydryl groups in bacteriostatic action of nitrite

    International Nuclear Information System (INIS)

    Buchman, G.W. III; Hansen, J.N.

    1987-01-01

    The mechanism by which nitrite inhibits outgrowing spores of bacillus cereus T was examined by using techniques developed earlier for nitrite analogs. The morphological stage of inhibition, cooperativity effects, effect of pH on inhibition, kinetics of protection against tritiated iodoacetate incorporation into membrane sulfhydryl groups, and protection against the bacteriocidal effect of carboxymethylation of iodoacetate indicate that nitrite acts as a membrane-directed sulfhydryl agent. The mechanism by which nitrite modifies the chemical reactivity of the sulfhyrdyl group could be either direct covalent modification or inactivation through communication with another modified membrane component. Profiles of pH effects suggest that the active agent is the protonated form of nitrite. The nitrite concentrations which modify membrane sulfhydryl activity coincide with those which have a bacteriostatic effect. These results are consistent with membrane sulfhydryl modification as a component of the mechanism of nitrite-induced bacteriostasis in this aerobic sporeformer

  17. Fluorometric determination of nitrite with 4-hydroxycoumarin

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, T.; Arai, Y.; Takitani, S.

    1986-12-01

    A simple, sensitive, and reproducible fluorometric method for determination of nitrite has been developed. This method is based on the nitrosation of 4-hydroxycoumarin in acidic medium and subsequent reduction to 3-amino-4-hydroxy-coumarin, which is fluorescent in alkaline medium. The fluorescence intensity is proportional to the nitrite concentration in the range of 3 ng/mL to 1 ..mu..g/mL in the sample solution, with a relative standard deviation of 0.5% (50 ng/mL). The method has been applied to the determination of nitrite in saliva.

  18. Impact of Clean-Label Antimicrobials and Nitrite Derived from Natural Sources on the Outgrowth of Clostridium perfringens during Cooling of Deli-Style Turkey Breast.

    Science.gov (United States)

    King, Amanda M; Glass, Kathleen A; Milkowski, Andrew L; Sindelar, Jeffrey J

    2015-05-01

    Organic acids and sodium nitrite have long been shown to provide antimicrobial activity during chilling of cured meat products. However, neither purified organic acids nor NaNO2 is permitted in products labeled natural and both are generally avoided in clean-label formulations; efficacy of their replacement is not well understood. Natural and clean-label antimicrobial alternatives were evaluated in both uncured and in alternative cured (a process that uses natural sources of nitrite) deli-style turkey breast to determine inhibition of Clostridium perfringens outgrowth during 15 h of chilling. Ten treatments of ground turkey breast (76% moisture, 1.2% salt) included a control and four antimicrobials: 1.0% tropical fruit extract, 0.7% dried vinegar, 1.0% cultured sugar-vinegar blend, and 2.0% lemon-vinegar blend. Each treatment was formulated without (uncured) and with nitrite (PCN; 50 ppm of NaNO2 from cultured celery juice powder). Treatments were inoculated with C. perfringens spores (three-strain mixture) to yield 2.5 log CFU/g. Individual 50-g portions were vacuum packaged, cooked to 71.1°C, and chilled from 54.4 to 26.7°C in 5 h and from 26.7 to 7.2°C in an additional 10 h. Triplicate samples were assayed for growth of C. perfringens at predetermined intervals by plating on tryptose-sulfite-cycloserine agar. Uncured control and PCN-only treatments allowed for 4.6- and 4.2-log increases at 15 h, respectively, and although all antimicrobial treatments allowed less outgrowth than uncured and PCN, the degree of inhibition varied. The 1.0% fruit extract and 1.0% cultured sugar-vinegar blend were effective at controlling populations at or below initial levels, whether or not PCN was included. Without PCN, 0.7% dried vinegar and 2.0% lemon-vinegar blend allowed for 2.0- and 2.5-log increases, respectively, and ∼1.5-log increases with PCN. Results suggest using clean-label antimicrobials can provide for safe cooling following the study parameters, and greater

  19. Aspects of calcium oxalate crystallization: theory, in vitro studies, and in vivo implementation.

    Science.gov (United States)

    Rodgers, A

    1999-11-01

    There are three main approaches to urolithiasis research: theory, basic science, and clinical implementation. Although each approach has yielded meaningful results, there does not appear to be complete synergy between them. This article examines these approaches as they pertain to urinary calcium oxalate crystallization processes. Theoretical calculations were performed to examine the role of oxalate concentration on calcium oxalate supersaturation. The effects of magnesium, citrate, and combinations thereof on calcium oxalate crystallization kinetics were examined in a mixed suspension, mixed product removal crystallizer. Finally, male volunteers were given supplements of calcium alone and binary combinations of calcium, magnesium, and citrate to investigate their effects on the urinary supersaturation of calcium oxalate. Calculations showed that oxalate is 23 times more potent than calcium in its effect on the supersaturation of calcium oxalate. In the in vitro experiments, magnesium and citrate reduced the growth and nucleation kinetics as well as the supersaturation. In combination, these two components were more effective than the individual components in reducing the growth rate and the supersaturation. All of the supplements favorably altered the kinetic and thermodynamic risk factors. Calcium was the most effective in reducing the urinary excretion of oxalate. Articulation of these three approaches is essential for the meaningful investigation and understanding of urolithiasis.

  20. Nebulization of the acidified sodium nitrite formulation attenuates acute hypoxic pulmonary vasoconstriction

    Directory of Open Access Journals (Sweden)

    Surber Mark W

    2010-06-01

    Full Text Available Abstract Background Generalized hypoxic pulmonary vasoconstriction (HPV occurring during exposure to hypoxia is a detrimental process resulting in an increase in lung vascular resistance. Nebulization of sodium nitrite has been shown to inhibit HPV. The aim of this project was to investigate and compare the effects of nebulization of nitrite and different formulations of acidified sodium nitrite on acute HPV. Methods Ex vivo isolated rabbit lungs perfused with erythrocytes in Krebs-Henseleit buffer (adjusted to 10% hematocrit and in vivo anesthetized catheterized rabbits were challenged with periods of hypoxic ventilation alternating with periods of normoxic ventilation. After baseline hypoxic challenges, vehicle, sodium nitrite or acidified sodium nitrite was delivered via nebulization. In the ex vivo model, pulmonary arterial pressure and nitric oxide concentrations in exhaled gas were monitored. Nitrite and nitrite/nitrate were measured in samples of perfusion buffer. Pulmonary arterial pressure, systemic arterial pressure, cardiac output and blood gases were monitored in the in vivo model. Results In the ex vivo model, nitrite nebulization attenuated HPV and increased nitric oxide concentrations in exhaled gas and nitrite concentrations in the perfusate. The acidified forms of sodium nitrite induced higher levels of nitric oxide in exhaled gas and had longer vasodilating effects compared to nitrite alone. All nitrite formulations increased concentrations of circulating nitrite to the same degree. In the in vivo model, inhaled nitrite inhibited HPV, while pulmonary arterial pressure, cardiac output and blood gases were not affected. All nitrite formulations had similar potency to inhibit HPV. The tested concentration of appeared tolerable. Conclusion Nitrite alone and in acidified forms effectively and similarly attenuates HPV. However, acidified nitrite formulations induce a more pronounced increase in nitric oxide exhalation.

  1. Sulfites and the wine metabolome.

    Science.gov (United States)

    Roullier-Gall, Chloé; Hemmler, Daniel; Gonsior, Michael; Li, Yan; Nikolantonaki, Maria; Aron, Alissa; Coelho, Christian; Gougeon, Régis D; Schmitt-Kopplin, Philippe

    2017-12-15

    In a context of societal concern about food preservation, the reduction of sulfite input plays a major role in the wine industry. To improve the understanding of the chemistry involved in the SO 2 protection, a series of bottle aged Chardonnay wines made from the same must, but with different concentrations of SO 2 added at pressing were analyzed by ultrahigh resolution mass spectrometry (FT-ICR-MS) and excitation emission matrix fluorescence (EEMF). Metabolic fingerprints from FT-ICR-MS data could discriminate wines according to the added concentration to the must but they also revealed chemistry-related differences according to the type of stopper, providing a wine metabolomics picture of the impact of distinct stopping strategies. Spearman rank correlation was applied to link the statistically modeled EEMF components (parallel factor analysis (PARAFAC)) and the exact mass information from FT-ICR-MS, and thus revealing the extent of sulfur-containing compounds which could show some correlation with fluorescence fingerprints. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Preparation of High-purity Indium Oxalate Salt from Indium Scrap by Organic Acids

    International Nuclear Information System (INIS)

    Koo, Su-Jin; Ju, Chang-Sik

    2013-01-01

    Effect of organic acid on the preparation of indium-oxalate salt from indium scraps generated from ITO glass manufacturing process was studied. Effects of parameters, such as type and concentration of organic acids, pH of reactant, temperature, reaction time on indium-oxalate salt preparation were examined. The impurity removal efficiency was similar for both oxalic acid and citric acid, but citric acid did not make organic acid salt with indium. The optimum conditions were 1.5 M oxalic acid, pH 7, 80 .deg. C, and 6 hours. On the other hand, the recoveries increased with pH, but the purity decreased. The indium-oxalate salt purity prepared by two cycles was 99.995% (4N5). The indium-oxalate salt could be converted to indium oxide and indium metal by substitution reaction and calcination

  3. Using sulfite chemistry for robust bioconversion of Douglas-fir forest residue to bioethanol at high titer and lignosulfonate: A pilot-scale evaluation

    Science.gov (United States)

    J.Y. Zhu; M. Subhosh Chandra; Feng Gu; Roland Gleisner; J.Y. Zhu; John Sessions; Gevan Marrs; Johnway Gao; Dwight Anderson

    2015-01-01

    This study demonstrated at the pilot-scale (50 kg) use of Douglas-fir forest harvest residue, an underutilized forest biomass, for the production of high titer and high yield bioethanol using sulfite chemistry without solid–liquor separation and detoxification. Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses (SPORL) was directly applied to the...

  4. Wu-Ling-San formula prophylaxis against recurrent calcium oxalate ...

    African Journals Online (AJOL)

    Wu-Ling-San (WLS) formula has been proved to prevent calcium oxalate nephrolithiasis both in vitro and in vivo. This is the first prospective, randomized and placebo-controlled clinical trial of WLS in calcium oxalate nephrolithiasis prevention. All patients who enrolled were asked to drink enough fluid to urinate at least 2 L ...

  5. Synthesis of unsymmetrical dimethylhydrazine oxalate from rejected liquid rocket propellant

    Science.gov (United States)

    Mu, Xiaogang; Yang, Jingjing; Zhang, Youzhi

    2018-02-01

    The rejected liquid propellant unsymmetrical dimethylhydrazine (UDMH) was converted to UDMH oxalate, which has commercial value. The UDMH oxalate structure and stability were investigated by the Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and ultraviolet-visible spectrophotometric analysis. The results indicate that UDMH oxalate has good thermal and aqueous solution stability, a melting point of 144 °C, an initial decomposition temperature of 180 °C, and a peak wavelength of UV in aqueous solution at λ = 204 nm. This disposal method of rejected UDMH is highly efficient and environmentally safe.

  6. Oxalate Encapsulation in Aqueous Medium by Tripodal Urea ...

    Indian Academy of Sciences (India)

    1H-NMR titration studies: All 1H-NMR titration experiments for L1 and L2 were conducted on a Bruker 300 MHz spectrometer at 298 K respectively. Potassium oxalate dihydrate (K2C2O4.2H2O) was used to prepare the stock solution of anion in DMSO-d6:D2O (1:1.1) solvent system. Lower solubility of potassium oxalate in ...

  7. [Nitrates and nitrites in meat products--nitrosamines precursors].

    Science.gov (United States)

    Avasilcăi, Liliana; Cuciureanu, Rodica

    2011-01-01

    To determine the content in nitrates and nitrites and the formation of two nitrosamines (N-nitrosodimethylamine--NDMA, and N-nitrosodiethylaamine--NDEA) in samples of chicken ham, dry Banat salami, dry French salami, traditional Romania sausages, and pork pastrami. Nitrites were determined by spectrophotometry with Peter-Griess reagent, and nitrates by the same method after reduction to nitrites with cadmium powder. High performance liquid chromatography with UV detection was used to determine nitrosamines. The initial concentration of nitrates, nitrites, NDMA and NDEA in the samples ranged as follows: 14.10-60.40 mg NO3/kg, 2.70-26.70 mg NO2/kg, from non-detectable to 0.90 microg NDMA/kg, and from non-detectable to 0.27 microg NDEA/kg, respectively. After 28 days the concentrations were: 3.24-17.1 mg NO3/kg, 0.04 -1.87 mg NO2/kg, 0.8-29 microg NDMA/kg, and 11.6-61.9 microg NDEA/kg, respectively. The decreased nitrate and nitrite and increased NDMA and NDEA concentrations prove that in food products nitrosamines are formed due to residual nitrite during their preservation. The determination of nitrasamines revealed levels much above the admitted maximal concentration for these food products.

  8. Plasma biochemistry and urinalysis variables of koalas (Phascolarctos cinereus) with and without oxalate nephrosis.

    Science.gov (United States)

    Speight, K Natasha; Haynes, Julie I; Boardman, Wayne; Breed, William G; Taggart, David A; Rich, Brian; Woolford, Lucy

    2014-06-01

    Oxalate nephrosis is a highly prevalent disease in the Mount Lofty Ranges koala population in South Australia, but associated clinicopathologic findings remain undescribed. The aims of this study were to determine plasma biochemical and urinalysis variables, particularly for renal function and urinary crystal morphology and composition, in koalas with oxalate nephrosis. Blood and urine samples from Mount Lofty Ranges koalas with oxalate nephrosis were compared with those unaffected by renal oxalate crystal deposition from Mount Lofty and Kangaroo Island, South Australia and Moggill, Queensland. Plasma and urine biochemistry variables were analyzed using a Cobas Bio analyzer, and urinary oxalate by high-performance liquid chromatography. Urinary crystal composition was determined by infrared spectroscopy and energy dispersive X-ray analysis. Azotemia (urea > 6.6 mmol/L, creatinine > 150 μmol/L) was found in 93% of koalas with oxalate nephrosis (n = 15). All azotemic animals had renal insufficiency (urine specific gravity [USG] < 1.035), and in 83%, USG was < 1.030. Koalas with oxalate nephrosis were hyperoxaluric compared with Queensland koalas (P < .01). Urinary crystals from koalas with oxalate nephrosis had atypical morphology and were composed of calcium oxalate. Mount Lofty Ranges koalas unaffected by renal oxalate crystal deposition had renal insufficiency (43%), although only 14% had USG < 1.030 (n = 7). Unaffected Mount Lofty Ranges and Kangaroo Island koalas were hyperoxaluric compared with Queensland koalas (P < .01). Koalas with oxalate nephrosis from the Mount Lofty Ranges had renal insufficiency, hyperoxaluria, and pathognomonic urinary crystals. The findings of this study will aid veterinary diagnosis of this disease. © 2014 American Society for Veterinary Clinical Pathology and European Society for Veterinary Clinical Pathology.

  9. Monitoring nitrite and nitrate residues in frankfurters during processing and storage.

    Science.gov (United States)

    Pérez-Rodríguez, M L; Bosch-Bosch, N; Garciá-Mata, M

    1996-09-01

    Frankfurter-type sausages were prepared in a pilot plant with different concentrations of NaNO(2) (75, 125 or 250 ppm) combined or not with 200 ppm KNO(3). A meat system, free of curing agents, was also used as control. Nitrite and nitrate levels were tested in various processing steps and over 120 days storage at 3 °C of the vacuum-packaged frankfurters. Little influence of the originally added nitrite level on the amount of nitrate formed was observed. Important losses of nitrite and nitrate were due to cooking. Thereafter about 50% of the nitrite added initially remained in this form in all samples (39, 59 and 146 ppm, respectively) and between 10 and 15% as nitrate. When only nitrate was initially added, formation of nitrite after cooking was observed (maximum level 43 ppm NaNO(2)). Formulations prepared with both nitrate and nitrite showed no significant differences (p nitrite or nitrate counterparts. A good correlation among nitrite and nitrate levels and storage time was showed by multiple linear regression analysis. It is concluded that the use of nitrate in combination with nitrite in cooked meat products seems to have little technological significance and adds to the total body burden of nitrite.

  10. NDA technique for the assay of wet plutonium oxalate

    International Nuclear Information System (INIS)

    Marshall, R.S.; Canada, T.R.

    1980-01-01

    A method has been developed to quantitatively measure batches of wet plutonium oxalate. The method is based on a count of coincidence neutrons to which a correction is applied for the effects of neutron moderation by water. A therma-neutron coincidence counter (TNC) with two concentric rings of 3 He detectors provides the signal needed for the water correction. The signal is the ratio of neutron counts between the detector rings that changes with the percent of water in plutonium oxalate. To evaluate the measurement technique, 26 batches of plutonium oxalate were measured in an in-line TNC. The evaluation showed the measurements to be essentially unbiased and precise to 2.2%

  11. Interaction Studies of Dilute Aqueous Oxalic Acid

    Directory of Open Access Journals (Sweden)

    Kiran Kandpal

    2007-01-01

    Full Text Available Molecular conductance λm, relative viscosity and density of oxalicacid at different concentration in dilute aqueous solution were measured at 293 K.The conductance data were used to calculate the value association constant.Viscosity and density data were used to calculate the A and B coefficient ofJone-Dole equation and apparent molar volume respectively. The viscosityresults were utilized for the applicability of Modified Jone-Dole equation andStaurdinger equations. Mono oxalate anion acts, as structure maker and thesolute-solvent interaction were present in the dilute aqueous oxalic acid.

  12. Neurotoxicity induced by alkyl nitrites: Impairment in learning/memory and motor coordination.

    Science.gov (United States)

    Cha, Hye Jin; Kim, Yun Ji; Jeon, Seo Young; Kim, Young-Hoon; Shin, Jisoon; Yun, Jaesuk; Han, Kyoungmoon; Park, Hye-Kyung; Kim, Hyung Soo

    2016-04-21

    Although alkyl nitrites are used as recreational drugs, there is only little research data regarding their effects on the central nervous system including their neurotoxicity. This study investigated the neurotoxicity of three representative alkyl nitrites (isobutyl nitrite, isoamyl nitrite, and butyl nitrite), and whether it affected learning/memory function and motor coordination in rodents. Morris water maze test was performed in mice after administrating the mice with varying doses of the substances in two different injection schedules of memory acquisition and memory retention. A rota-rod test was then performed in rats. All tested alkyl nitrites lowered the rodents' capacity for learning and memory, as assessed by both the acquisition and retention tests. The results of the rota-rod test showed that isobutyl nitrite in particular impaired motor coordination in chronically treated rats. The mice chronically injected with isoamyl nitrite also showed impaired function, while butyl nitrite had no significant effect. The results of the water maze test suggest that alkyl nitrites may impair learning and memory. Additionally, isoamyl nitrite affected the rodents' motor coordination ability. Collectively, our findings suggest that alkyl nitrites may induce neurotoxicity, especially on the aspect of learning and memory function. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. 9 CFR 319.2 - Products and nitrates and nitrites.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Products and nitrates and nitrites... and nitrates and nitrites. Any product, such as frankfurters and corned beef, for which there is a standard in this part and to which nitrate or nitrite is permitted or required to be added, may be prepared...

  14. Dynamic process model of a plutonium oxalate precipitator. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Miller, C.L.; Hammelman, J.E.; Borgonovi, G.M.

    1977-11-01

    In support of LLL material safeguards program, a dynamic process model was developed which simulates the performance of a plutonium (IV) oxalate precipitator. The plutonium oxalate precipitator is a component in the plutonium oxalate process for making plutonium oxide powder from plutonium nitrate. The model is based on state-of-the-art crystallization descriptive equations, the parameters of which are quantified through the use of batch experimental data. The dynamic model predicts performance very similar to general Hanford oxalate process experience. The utilization of such a process model in an actual plant operation could promote both process control and material safeguards control by serving as a baseline predictor which could give early warning of process upsets or material diversion. The model has been incorporated into a FORTRAN computer program and is also compatible with the DYNSYS 2 computer code which is being used at LLL for process modeling efforts.

  15. Dynamic process model of a plutonium oxalate precipitator. Final report

    International Nuclear Information System (INIS)

    Miller, C.L.; Hammelman, J.E.; Borgonovi, G.M.

    1977-11-01

    In support of LLL material safeguards program, a dynamic process model was developed which simulates the performance of a plutonium (IV) oxalate precipitator. The plutonium oxalate precipitator is a component in the plutonium oxalate process for making plutonium oxide powder from plutonium nitrate. The model is based on state-of-the-art crystallization descriptive equations, the parameters of which are quantified through the use of batch experimental data. The dynamic model predicts performance very similar to general Hanford oxalate process experience. The utilization of such a process model in an actual plant operation could promote both process control and material safeguards control by serving as a baseline predictor which could give early warning of process upsets or material diversion. The model has been incorporated into a FORTRAN computer program and is also compatible with the DYNSYS 2 computer code which is being used at LLL for process modeling efforts

  16. Characterization of oxalate-based 237NpO2 powder

    International Nuclear Information System (INIS)

    Rankin, D.T.; Burney, G.A.; Smith, P.K.; Sisson, R.D.

    1976-01-01

    238 Pu, a radioisotope heat source, is produced by irradiating reactor targets containing 237 NpO 2 . The neptunium oxide is obtained by precipitating and calcining 237 Np(IV) oxalate. The effects of oxalate precipitation parameters on particle morphology and size distribution of 237 NpO 2 powder were established to provide process controls for fabricating reactor targets

  17. THE SPECTROPHOTOMETRIC DETERMINATION OF NITRITES WITH N,N-DIETHYLANILINE

    Directory of Open Access Journals (Sweden)

    O. S. Pogrebnyak

    2015-11-01

    Full Text Available A new spectrophotometric method for nitrite determination was proposed. The method is based on the measurement of absorbance of the N,N-diethylaniline nitrosation product at 475 nm in the hydrochloric acid medium. The optimum concentrations and the influence of various conditions on the determination sensitivity have been determined. The detection limit (blank + 3s for nitrite is 0.98 mg∙L–1 where sis the standard deviation of blank estimation. The linearity range of the calibration graph was over 1.0–100 mg∙L–1 of  nitrite (sr≤ 0.029, n = 8. The metrological characteristics of the procedure were checked by means of method of additives on the control samples and natural waters. The relative error did not exceed 0.06 for nitrite determination on the control samples. The effect of foreign ions in nitrite determination of 1,0∙10−3 mol∙L–1 has been studied. The proposed procedure is simple  and suitable for nitrite determination in various objects.

  18. Interactions of nitrite with catalase: Enzyme activity and reaction kinetics studies.

    Science.gov (United States)

    Krych-Madej, Justyna; Gebicka, Lidia

    2017-06-01

    Catalase, a heme enzyme, which catalyzes decomposition of hydrogen peroxide to water and molecular oxygen, is one of the main enzymes of the antioxidant defense system of the cell. Nitrite, used as a food preservative has long been regarded as a harmful compound due to its ability to form carcinogenic nitrosamines. Recently, much evidence has been presented that nitrite plays a protective role as a nitric oxide donor under hypoxic conditions. In this work the effect of nitrite on the catalytic reactions of catalase was studied. Catalase was inhibited by nitrite, and this process was pH-dependent. IC 50 values varied from about 1μM at pH5.0 to about 150μM of nitrite at pH7.4. The presence of chloride significantly enhanced nitrite-induced catalase inhibition, in agreement with earlier observations. The kinetics of the reactions of nitrite with ferric catalase, its redox intermediate, Compound I, and catalase inactive form, Compound II, was also studied. Possible mechanisms of nitrite-induced catalase inhibition are analyzed and the biological consequences of the reactions of catalase with nitrite are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Total salivary nitrates and nitrites in oral health and periodontal disease.

    Science.gov (United States)

    Sánchez, Gabriel A; Miozza, Valeria A; Delgado, Alejandra; Busch, Lucila

    2014-01-30

    It is well known that nitrites are increased in saliva from patients with periodontal disease. In the oral cavity, nitrites may derive partly from the reduction of nitrates by oral bacteria. Nitrates have been reported as a defence-related mechanism. Thus, the aim of the present study was to determine the salivary levels of total nitrate and nitrite and their relationship, in unstimulated and stimulated saliva from periodontal healthy subjects, and from patients with chronic periodontal disease. Nitrates and nitrites were determined in saliva from thirty healthy subjects and forty-four patients with periodontal disease. A significant increase in salivary nitrates and nitrites was observed. Nitrates and nitrites concentration was related to clinical attachment level (CAL). A positive and significant Pearson's correlation was found between salivary total nitrates and nitrites. Periodontal treatment induced clinical improvement and decreased nitrates and nitrites. It is concluded that salivary nitrates and nitrites increase, in patients with periodontal disease, could be related to defence mechanisms. The possibility that the salivary glands respond to oral infectious diseases by increasing nitrate secretion should be explored further. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Ultrastructural and biochemical studies on formation of calcium oxalate in plants

    International Nuclear Information System (INIS)

    Abdelmottaleb, A.M.

    1989-01-01

    Plant calcium oxalate crystals occur within cells called crystal idioblasts. Important aspects of this calcification phenomenon have not been characterized. This dissertation examines some of the aspects of this ubiquitous type of calcification including (1) characterization of ultrastructural features of developing crystal idioblasts, (2) determination of the relationship of specialized ultrastructural features of the idioblasts to transport of compounds and mechanisms of crystal deposition, and (3) the biochemical relationship between ascorbic acid metabolism and production of oxalic acid used for crystal formation. Structural and cytochemical studies revealed that crystal idioblasts have dense cytoplasm, modified plastids, enlarged nuclei, extensive endoplasmic reticulum, numerous dictyosomes and vesicles, and a bundle of raphide crystals in their vacuoles. A mechanism for Ca transport and crystal precipitation is proposed, based on these results. There is a strong and dynamic relationship between Ca concentration and oxalic acid produced for crystal formation, where increasing Ca level in the growth medium lead to increased total and insoluble oxalate in the plant. Calmodulin antagonists reduced oxalic acid production

  1. Sodium nitrite: the "cure" for nitric oxide insufficiency.

    Science.gov (United States)

    Parthasarathy, Deepa K; Bryan, Nathan S

    2012-11-01

    This process of "curing" food is a long practice that dates back thousands of years long before refrigeration or food safety regulations. Today food safety and mass manufacturing are dependent upon safe and effective means to cure and preserve foods including meats. Nitrite remains the most effective curing agent to prevent food spoilage and bacterial contamination. Despite decades of rigorous research on its safety and efficacy as a curing agent, it is still regarded by many as a toxic undesirable food additive. However, research within the biomedical science community has revealed enormous therapeutic benefits of nitrite that is currently being developed as novel therapies for conditions associated with nitric oxide (NO) insufficiency. Much of the same biochemistry that has been understood for decades in the meat industry has been rediscovered in human physiology. This review will highlight the fundamental biochemistry of nitrite in human physiology and highlight the risk benefit evaluation surrounding nitrite in food and meat products. Foods or diets enriched with nitrite can have profound positive health benefits. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Consensus structures of the Mo(v) sites of sulfite-oxidizing enzymes derived from variable frequency pulsed EPR spectroscopy, isotopic labelling and DFT calculations.

    Science.gov (United States)

    Enemark, John H

    2017-10-10

    Sulfite-oxidizing enzymes from eukaryotes and prokaryotes have five-coordinate distorted square-pyramidal coordination about the molybdenum atom. The paramagnetic Mo(v) state is easily generated, and over the years four distinct CW EPR spectra have been identified, depending upon enzyme source and the reaction conditions, namely high and low pH (hpH and lpH), phosphate inhibited (P i ) and sulfite (or blocked). Extensive studies of these paramagnetic forms of sulfite-oxidizing enzymes using variable frequency pulsed electron spin echo (ESE) spectroscopy, isotopic labeling and density functional theory (DFT) calculations have led to the consensus structures that are described here. Errors in some of the previously proposed structures are corrected.

  3. Influence of turkey meat on residual nitrite in cured meat products.

    Science.gov (United States)

    Kilic, B; Cassens, R G; Borchert, L L

    2001-02-01

    A response surface experimental design was employed to estimate residual nitrite level at various initial nitrite concentrations, percent turkey meat in the formula, and heat quantity (F) values using a typical wiener as the test system. Pork and mechanically separated turkey were used as the meat ingredients. Residual nitrite and pH were measured at day 1, 7 days, 14 days, and 49 days after processing. Protein, fat, salt, moisture, and CIE (L*a*b*) color values were also determined. Results showed that the effect of turkey meat on residual nitrite level was significant (P meat in the formula resulted in lower residual nitrite levels at a fixed pH. The residual nitrite level was initially proportional to initial nitrite concentration, but it became a nonsignificant factor during longer storage time. Differences in heat quantity had a significant effect (P nitrite level initially. Greater heat quantity decreased residual nitrite level in finished cured meat products at a fixed pH. However, this effect became nonsignificant during longer storage. Reduction of residual nitrite in wieners because of turkey meat addition at a fixed pH was due to characteristics of the turkey tissue, but the mechanism of action remains unknown. It was also established that commercial wieners had a higher pH if poultry meat was included in the formulation.

  4. Corrosion and impedance studies on magnesium alloy in oxalate solution

    International Nuclear Information System (INIS)

    Fekry, A.M.; Tammam, Riham H.

    2011-01-01

    Highlights: → Corrosion behavior of AZ91E alloy was investigated in 0.1 M Na 2 C 2 O 4 containing different additives as Br - , Cl - or Silicate. → The corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na 2 C 2 O 4 ). This was confirmed by scanning electron microscope (SEM) observations. → For the other added ions Br - or Cl - , the corrosion rate is higher than the blank. - Abstract: Corrosion behavior of AZ91E alloy was investigated in oxalate solution using potentiodynamic polarization and electrochemical impedance measurements (EIS). The effect of oxalate concentration was studied, where the corrosion rate increases with increasing oxalate concentration. The effect of added ions (Br - , Cl - or SiO 3 2- ) on the electrochemical behavior of magnesium alloy in 0.1 M Na 2 C 2 O 4 solution at 298 K, was investigated. It was found that the corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na 2 C 2 O 4 ). This was confirmed by scanning electron microscope (SEM) observations. However, for the other added ions Br - or Cl - , the corrosion rate is higher than the blank.

  5. Oxalate complexation in dissolved carbide systems

    International Nuclear Information System (INIS)

    Choppin, G.R.; Bokelund, H.; Valkiers, S.

    1983-01-01

    It has been shown that the oxalic acid produced in the dissolution of mixed uranium, plutonium carbides in nitric acid can account for the problems of incomplete uranium and plutonium extraction on the Purex process. Moreover, it was demonstrated that other identified products such as benzene polycarboxylic acids are either too insoluble or insufficiently complexing to be of concern. The stability constants for oxalate complexing of UO 2 +2 and Pu +4 ions (as UO 2 (C 2 O 4 ), Pu(C 2 O 4 ) 2+ and Pu(C 2 O 4 ) 2 , respectively) were measured in nitrate solutions of 4.0 molar ionic strength (0-4 M HNO 3 ) by extraction of these species with TBP. (orig.)

  6. Excessive nitrite affects zebrafish valvulogenesis through yielding too much NO signaling.

    Directory of Open Access Journals (Sweden)

    Junbo Li

    Full Text Available Sodium nitrite, a common food additive, exists widely not only in the environment but also in our body. Excessive nitrite causes toxicological effects on human health; however, whether it affects vertebrate heart valve development remains unknown. In vertebrates, developmental defects of cardiac valves usually lead to congenital heart disease. To understand the toxic effects of nitrite on valvulogenesis, we exposed zebrafish embryos with different concentrations of sodium nitrite. Our results showed that sodium nitrite caused developmental defects of zebrafish heart dose dependently. It affected zebrafish heart development starting from 36 hpf (hour post fertilization when heart initiates looping process. Comprehensive analysis on the embryos at 24 hpf and 48 hpf showed that excessive nitrite did not affect blood circulation, vascular network, myocardium and endocardium development. But development of endocardial cells in atrioventricular canal (AVC of the embryos at 48 hpf was disrupted by too much nitrite, leading to defective formation of primitive valve leaflets at 76 hpf. Consistently, excessive nitrite diminished expressions of valve progenitor markers including bmp4, has2, vcana and notch1b at 48 hpf. Furthermore, 3', 5'-cyclic guanosine monophosphate (cGMP, downstream of nitric oxide (NO signaling, was increased its level significantly in the embryos exposed with excessive nitrite and microinjection of soluble guanylate cyclase inhibitor ODQ (1H-[1], [2], [4]Oxadiazolo[4,3-a] quinoxalin-1-one, an antagonist of NO signaling, into nitrite-exposed embryos could partly rescue the cardiac valve malformation. Taken together, our results show that excessive nitrite affects early valve leaflet formation by producing too much NO signaling.

  7. Studies on removal of plutonium from oxalic acid containing hydrochloric acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ghadse, D R; Noronha, D M; Joshi, A R [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Solution containing hydrochloric acid, oxalic acid and considerable quantities of plutonium may be generated while recycling of scrap produced during the metallic fuel fabrication. Plutonium from such waste is normally recovered by anion exchange method after the destruction of oxalic acid using suitable oxidising agent. Solvent extraction and ion exchange methods are being explored in this laboratory for recovery of Pu from oxalic acid containing HCl solutions without prior destruction of oxalic acid. This paper describes the results on the determination of distribution ratios for extraction of Pu(IV) from hydrochloric acid using Aliquot-336 or HDEHP under varying experimental conditions. (author). 5 refs., 5 tabs.

  8. Influence of nutrition on feline calcium oxalate urolithiasis with emphasis on endogenous oxalate synthesis

    NARCIS (Netherlands)

    Dijcker, J.C.; Plantinga, E.A.; Baal, van J.; Hendriks, W.H.

    2011-01-01

    The prevalence of calcium oxalate (CaOx) uroliths detected in cats with lower urinary tract disease has shown a sharp increase over the last decades with a concomitant reciprocal decrease in the occurrence of struvite (magnesium ammonium phosphate) uroliths. CaOx stone-preventative diets are

  9. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    Directory of Open Access Journals (Sweden)

    G. Cailleau

    2011-07-01

    Full Text Available An African oxalogenic tree, the iroko tree (Milicia excelsa, has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the acidic conditions in these types of soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from field to microscopic scales. In the first centimeters of the soil profile, decaying of the organic matter allows the release of whewellite crystals, mainly due to the action of termites and saprophytic fungi. In addition, a concomitant flux of carbonate formed in wood tissues contributes to the carbonate flux and is identified as a direct consequence of wood feeding by termites. Nevertheless, calcite biomineralization of the tree is not a consequence of in situ oxalate consumption, but rather related to the oxalate oxidation inside the upper part of the soil. The consequence of this oxidation is the presence of carbonate ions in the soil solution pumped through the roots, leading to preferential mineralization of the roots and the trunk base. An ideal scenario for the iroko biomineralization and soil carbonate accumulation starts with oxalatization: as the iroko tree grows, the organic matter flux to the soil constitutes the litter, and an oxalate pool is formed on the forest ground. Then, wood rotting agents (mainly termites, saprophytic fungi, and bacteria release significant amounts of oxalate crystals from decaying plant tissues. In addition, some of these agents are themselves producers of oxalate (e.g. fungi. Both processes contribute to a soil pool of "available" oxalate crystals. Oxalate consumption by oxalotrophic bacteria can then start. Carbonate and calcium ions present in the soil solution represent the end products of the oxalate

  10. Nitrate and nitrite in biology, nutrition and therapeutics

    Science.gov (United States)

    Lundberg, Jon O.; Gladwin, Mark T.; Ahluwalia, Amrita; Benjamin, Nigel; Bryan, Nathan S.; Butler, Anthony; Cabrales, Pedro; Fago, Angela; Feelisch, Martin; Ford, Peter C.; Freeman, Bruce A.; Frenneau, Michael; Friedman, Joel; Kelm, Malte; Kevil, Christopher G.; Kim-Shapiro, Daniel B.; Kozlov, Andrey V.; Lancaster, Jack R.; Lefer, David J.; McColl, Kenneth; McCurry, Kenneth; Patel, Rakesh; Petersson, Joel; Rassaf, Tienush; Reutov, Valentin P.; Richter-Addo, George B.; Schechter, Alan; Shiva, Sruti; Tsuchiya, Koichiro; van Faassen, Ernst E.; Webb, Andrew J.; Zuckerbraun, Brian S.; Zweier, Jay L.; Weitzberg, Eddie

    2014-01-01

    Inorganic nitrate and nitrite from endogenous or dietary sources are metabolized in vivo to nitric oxide (NO) and other bioactive nitrogen oxides. The nitrate-nitrite-NO pathway is emerging as an important mediator of blood flow regulation, cell signaling, energetics and tissue responses to hypoxia. The latest advances in our understanding of the biochemistry, physiology and therapeutics of nitrate, nitrite and NO were discussed during a recent two-day meeting at the Nobel Forum, Karolinska Institutet in Stockholm. PMID:19915529

  11. Anoxic sulfide biooxidation using nitrite as electron acceptor

    International Nuclear Information System (INIS)

    Mahmood, Qaisar; Zheng Ping; Cai Jing; Wu Donglei; Hu, Baolan; Li Jinye

    2007-01-01

    Biotechnology can be used to assess the well being of ecosystems, transform pollutants into benign substances, generate biodegradable materials from renewable sources, and develop environmentally safe manufacturing and disposal processes. Simultaneous elimination of sulfide and nitrite from synthetic wastewaters was investigated using a bioreactor. A laboratory scale anoxic sulfide-oxidizing (ASO) reactor was operated for 135 days to evaluate the potential for volumetric loading rates, effect of hydraulic retention time (HRT) and substrate concentration on the process performance. The maximal sulfide and nitrite removal rates were achieved to be 13.82 and 16.311 kg/(m 3 day), respectively, at 0.10 day HRT. The process can endure high sulfide concentrations, as the sulfide removal percentage always remained higher than 88.97% with influent concentration up to 1920 mg/L. Incomplete sulfide oxidation took place due to lower consumed nitrite to sulfide ratios of 0.93. It also tolerated high nitrite concentration up to 2265.25 mg/L. The potential achieved by decreasing HRT at fixed substrate concentration is higher than that by increasing substrate concentration at fixed HRT. The process can bear short HRT of 0.10 day but careful operation is needed. Nitrite conversion was more sensitive to HRT than sulfide conversion when HRT was decreased from 1.50 to 0.08 day. Stoichiometric analyses and results of batch experiments show that major part of sulfide (89-90%) was reduced by nitrite while some autooxidation (10-11%) was resulted from presence of small quantities of dissolved oxygen in the influent wastewater. There was ammonia amassing in considerably high amounts in the bioreactor when the influent nitrite concentration reached above 2265.25 mg/L. High ammonia concentrations (200-550 mg/L) in the bioreactor contributed towards the overall inhibition of the process. Present biotechnology exhibits practical value with a high potential for simultaneous removal of nitrite

  12. Oxalate Mass Balance During Chemical Cleaning in Tank 5F

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M.; Fink, S.

    2011-07-08

    The Savannah River Site (SRS) is preparing Tank 5F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRS personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 5F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate.

  13. A carbon nanotube/polyvanillin composite film as an electrocatalyst for the electrochemical oxidation of nitrite and its application as a nitrite sensor

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Dongyun [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences (China); Hu Chengguo [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences (China)], E-mail: cghu@whu.edu.cn; Peng Yanfen [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences (China); Hu Shengshui [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences (China)], E-mail: sshu@whu.edu.cn

    2009-08-30

    We report a simple method for the stable dispersion of multi-walled carbon nanotubes (MWNTs) in water by vanillin and controllable surface addition onto carbon fiber microelectrodes (CFE) via electropolymerization. We have characterized these polyvanillin-carbon nanotube (PVN-MWNT) composite films with techniques including scanning electron microscopy (SEM), infrared spectroscopy (IR) and voltammetry. These investigations showed that the films have a uniform porous nanostructure with a large surface area. This PVN-MWNT composite-modified CFE (PVN-MWNT/CFE) exhibited a sensitive response to the electrochemical oxidation of nitrite. Under optimal working conditions, the oxidation peak current of nitrite linearly increased with its concentration in the range of 0.2 {mu}M-3.1 mM, with the system exhibiting a lower detection limit of 50 nM (S/N = 3). We successfully applied the PVN-MWNT/CFE system to the determination of nitrite from lake water. The efficient recovery of nitrite indicated that this electrode was able to detect nitrite in real samples.

  14. Protection of metal artefacts with the formation of metal-oxalates complexes by Beauveria bassiana.

    Directory of Open Access Journals (Sweden)

    Edith eJoseph

    2012-01-01

    Full Text Available Several fungi present high tolerance to toxic metals and some are able to transform metals into metal-oxalate complexes. In this study, the ability of Beauveria bassiana to produce copper oxalates was evaluated in vitro. Growth performance was tested on various copper-containing media. B. bassiana proved highly resistant to copper, tolerating concentrations of up to 20 g.L-1, and precipitating copper oxalates on all media tested. Chromatographic analyses showed that this species produced oxalic acid as sole metal chelator. The production of metal-oxalates can be used in the restoration and conservation of archaeological and modern metal artefacts. The production of copper-oxalates was confirmed directly using metallic pieces (both archaeological and modern. The conversion of corrosion products into copper oxalates was demonstrated as well. In order to assess whether the capability of B. bassiana to produce metal-oxalates could be applied to other metals, iron and silver were tested as well. Iron appears to be directly sequestered in the wall of the fungal hyphae forming oxalates and probably goethite. However, the formation of a homogeneous layer on the object is not yet optimal. Silver nitrate was extracellularly reduced into nanoparticles of elemental silver by an unknown mechanism. The production of copper oxalates is immediately applicable for the conservation of copper-based artefacts. For iron and silver this is not yet the case. However, the vast ability of B. bassiana to transform toxic metals using different immobilization mechanisms seems to offer considerable possibilities for industrial applications, such as the bioremediation of contaminated soils or the green synthesis of chemicals.

  15. Probable functions of calcium oxalate crystals in different tissues of ...

    African Journals Online (AJOL)

    Representatives of seven major edible aroid accessions were screened for calcium oxalate using standard histochemical methods. All the accessions were noted to contain calcium oxalate in the forms of raphide bundles and intra-amylar crystals. The crystals were widely present in all parts of the plants including spongy ...

  16. Mutagenicity of some alkyl nitrites used as recreational drugs

    Energy Technology Data Exchange (ETDEWEB)

    Dunkel, V.C.; Cameron, T.P. (National Institute of Health, Bethesda (USA)); Rogers-Back, A.M.; Lawlor, T.E.; Harbell, J.W. (Microbiological Associates Inc., Rockville, MD (USA))

    1989-01-01

    When the AIDS epidemic was in its earliest stages, and prior to identification of HIV as the etiological factor, the use of volatile nitrites by the male homosexual community to enhance sexual activities appeared to have a significant role in this disease. Preliminary observations indicated that that portion of the male homosexual community which developed Kaposi's sarcoma were also heavy nitrite users. These nitrites had been demonstrated to be mutagenic in bacteria and thus it was postulated that they could be responsible for the appearance of the sarcoma. To evaluate further the genotoxic activity of these chemicals, six nitrites, including those most commonly used by homosexuals for sexual gratification, were selected for testing in the mouse lymphoma TK {plus minus} and Salmonell typhimurium mutagenicity assays. One chemical, n-amyl nitrite, was negative in the mouse lymphoma assay, while the other five chemicals, n-butyl, isobutyl, iso-amyl, sec-butyl, and n-propyl nitrite, were positive. All six compounds were positive in the Salmonella assay. The mutagenic and known toxic effects of these chemicals remain a concern because a large population of teenagers and young adults continue to abuse these substances.

  17. A Review of Nitrate and Nitrite Toxicity in Foods

    Directory of Open Access Journals (Sweden)

    Mir-Jamal Hosseini

    2016-03-01

    Full Text Available Agricultural advancement and population growth have prompted increases in food supplies, and higher crop yields have been made possible through the application of fertilizers. Large quantities of livestock and poultry on farms, along with the accumulation of biomass and agricultural residues, can cause contamination of ground water resources and other water sanitation concerns in both developing and developed countries. Nitrate is mainly used as a fertilizer in agriculture, and because of its high solubility in water, it can create biological problems in the environment. High usage of nitrite in the food industry as a preservative, flavor enhancer, antioxidant, and color stabilizing agent can cause human exposure to this toxic compound. Nitrite is 10 times as toxic as nitrate in humans. Nitrate is converted to nitrite and nitrosamine compounds in the human stomach, which can lead to bladder cancer. In this review, sources of nitrate and nitrite exposure were investigated. Furthermore, the review evaluates standard levels of nitrate and nitrite in different foods, and acceptable daily doses of these compounds in various countries. Finally, we discuss valid methods of nitrate and nitrite identification and removal in foods.

  18. (Di­methyl­phosphor­yl)methanaminium hydrogen oxalate–oxalic acid (2/1)

    OpenAIRE

    Bialek, Sebastian; Clemens, Rebecca; Reiss, Guido J.

    2014-01-01

    The reaction of (di­methyl­phosphor­yl)methanamine (dpma) with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4 −·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-mol­ecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16°) whereas the ox...

  19. Successful treatment of sodium oxalate induced urolithiasis with Helichrysum flowers.

    Science.gov (United States)

    Onaran, Metin; Orhan, Nilüfer; Farahvash, Amirali; Ekin, Hasya Nazlı; Kocabıyık, Murat; Gönül, İpek Işık; Şen, İlker; Aslan, Mustafa

    2016-06-20

    Helichrysum (Asteraceae) flowers, known as "altın otu, yayla çiçeği, kudama çiçeği" , are widely used to remove kidney stones and for their diuretic properties in Turkey. To determine the curative effect of infusions prepared from capitulums of Helichrysum graveolens (M. Bieb.) Sweet (HG) and H. stoechas ssp. barellieri (Ten.) Nyman (HS) on sodium oxalate induced kidney stones. Infusions prepared from the capitulums of HG and HS were tested for their curative effect on calcium oxalate deposition induced by sodium oxalate (70mg/kg i.p.). Following the injection of sodium oxalate for 5 days, plant extracts were administered to rats at two different doses. Potassium citrate was used as positive control. Water intake, urine volume, body, liver and kidney weights were measured; biochemical and hematological analyses were conducted on urine and blood samples. Additionally, histopathological examinations were done on kidney samples. H. stoechas extract showed prominent effect at 156mg/kg dose (stone formation score: 0.33), whereas number of kidney stones was maximum in sodium oxalate group (stone formation score: 2.33). The reduction in the uric acid and oxalate levels of urine samples and the elevation in the urine citrate levels are significant and promising in extract groups. Some hematological, biochemical and enzymatic markers are also ameliorated by the extracts. This is the first report on the curative effect of immortal flowers. Our preliminary study indicated that Helichrysum extracts may be used for treatment of urolithiasis and Helichrysum extracts are an alternative therapy to potassium citrate for patients suffering from kidney stones. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Synthesis and characterization of new oxalate ester-polymer composites for practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Petre, Razvan [Scientific Research Centre for CBRN Defense and Ecology, 225 Sos. Oltenitei, Bucharest 041309 (Romania); University POLITEHNICA of Bucharest, 149 Calea Victoriei, Bucharest 010072 (Romania); Zecheru, Teodora, E-mail: teodora.zecheru@yahoo.com [Scientific Research Centre for CBRN Defense and Ecology, 225 Sos. Oltenitei, Bucharest 041309 (Romania)

    2013-03-15

    The present study focused on the synthesis of high purity oxalate esters: bis(2,4,6-trichlorophenyl) oxalate (TCPO) and bis(2,4,5-trichloro-6-carbobutoxyphenyl) oxalate (TCCBPO), and further on their incorporation into potentially applicative polymer composites. The organic compounds were characterized through NMR and the composites obtained were evaluated for light capacity availability at room temperature and low temperatures. The concentrations of the peroxide, fluorescer, catalyst, and polymer additives were optimized. The chemiluminescent composites' performances were evaluated after 360 days and returned satisfactory results. - Highlights: Black-Right-Pointing-Pointer bis(2,4,6-Trichlorophenyl)-oxalate (TCPO) was synthesized. Black-Right-Pointing-Pointer bis(2,4,5-Trichloro-6-carbobutoxiphenyl)-oxalate (TCCBPO) was synthesized. Black-Right-Pointing-Pointer TCPO and TCCBPO-based composites were obtained. Black-Right-Pointing-Pointer The composites light emission was evaluated versus scotopic visual sensitivity. Black-Right-Pointing-Pointer The new compositions present superior performances within extensive emission time.

  1. Enhanced nitrogen availability in karst ecosystems by oxalic acid release in the rhizosphere

    Directory of Open Access Journals (Sweden)

    Fujing ePan

    2016-05-01

    Full Text Available In karst ecosystems, a high level of CaCO3 enhances the stabilization of soil organic matter (SOM and causes nitrogen (N and/or phosphorus (P limitation in plants. Oxalic acid has been suggested to be involved in the nutrient-acquisition strategy of plants because its addition can temporarily relieve nutrient limitation. Therefore, understanding how oxalic acid drives N availability may help support successful vegetation restoration in the karst ecosystems of southwest China. We tested a model suggested by Clarholm et al. (2015 where oxalate reacts with Ca bridges in SOM, thus exposing previously protected areas to enzymatic attacks in a way that releases N for local uptake. We studied the effects of oxalic acid, microbial biomass C (MBC, and β-1,4-N-acetylglucosaminidase (NAG on potential N mineralization rates in rhizosphere soils of four plant species (two shrubs and two trees in karst areas. The results showed that rhizosphere soils of shrubs grown on formerly deforested land had significantly lower oxalic acid concentrations and NAG activity than that of trees in a 200-year-old forest. The levels of MBC in rhizosphere soils of shrubs were significantly lower than those of trees in the growing season, but the measure of shrubs and trees were similar in the non-growing season; the potential N mineralization rates showed a reverse pattern. Positive relationships were found among oxalic acid, MBC, NAG activity, and potential N mineralization rates for both shrubs and trees. This indicated that oxalic acid, microbes, and NAG may enhance N availability for acquisition by plants. Path analysis showed that oxalic acid enhanced potential N mineralization rates indirectly through inducing microbes and NAG activities. We found that the exudation of oxalic acid clearly provides an important mechanism that allows plants to enhance nutrient acquisition in karst ecosystems.

  2. Enhanced Chemical Cleaning: Effectiveness Of The UV Lamp To Decompose Oxalates

    International Nuclear Information System (INIS)

    Ketusky, E.; Huff, T.; Sudduth, C.

    2010-01-01

    Enhanced Chemical Cleaning is a new process scheduled to begin cleaning Savannah River Site High Level Waste Tanks in 2012. It is an improvement over the current chemical cleaning method, in that it minimizes downstream impacts on the High Level Waste System. It is based on a state of the art scale removal process used on the secondary side of nuclear power plants, with modifications to accommodate the unique constraints created by the tanks. Both Enhanced Chemical Cleaning and the scale removal process are founded on dissolving metal oxides/hydroxides using oxalic acid, with subsequent oxalate decomposition via hydroxylation using ozone or peroxide, and UV light as a catalyst. A divergence Enhanced Chemical Cleaning has from nuclear power scale removal is the significantly increased solids concentration during oxalate decomposition. These solids can limit the ability of the UV light to create hydroxyl radicals, either by limiting the ability of the light to penetrate through the solution, or by increasing the fouling rate on the UV light. Both will decrease the overall catalytic effectiveness, thereby decreasing the concentration of formed hydroxyl radicals. The hydroxyl radicals are the driving force behind the oxalate decomposition. To understand the impact of increased solids, testing was performed using a medium pressure UV light inside an ozone supplied Oxalate Decomposition Reactor. Using a dissolved metal sludge simulant with an initial oxalate concentration greater than 12,000 ppm, and an initial pH of about 2.0, the spent acid solution was recirculated through the reactor, while the UV light was allowed to foul. For the first few hours, the oxalate decomposition rate was about 1,300 ppm/hour. After about 3 hours, enough time for the UV lamp to foul, the oxalate decomposition rate decreased to about 500 ppm/hour. The decomposition rate then remained roughly constant for the next 16 hours. Overall, testing showed that the oxalate destruction rate decreased

  3. Hydrothermal growth of cross-linked hyperbranched copper dendrites using copper oxalate complex

    Science.gov (United States)

    Truong, Quang Duc; Kakihana, Masato

    2012-06-01

    A facile and surfactant-free approach has been developed for the synthesis of cross-linked hyperbranched copper dendrites using copper oxalate complex as a precursor and oxalic acid as a reducing and structure-directing agent. The synthesized particles are composed of highly branched nanostructures with unusual cross-linked hierarchical networks. The formation of copper dendrites can be explained in view of both diffusion control and aggregation-based growth model accompanied by the chelation-assisted assembly. Oxalic acid was found to play dual roles as reducing and structure-directing agent based on the investigation results. The understanding on the crystal growth and the roles of oxalic acid provides clear insight into the formation mechanism of hyperbranched metal dendrites.

  4. Measurement of plutonium oxalate in thermal neutron coincidence counters

    International Nuclear Information System (INIS)

    Marshall, R.S.; Erkkila, B.H.

    1979-01-01

    A coincidence neutron counting method has been developed for assaying batches of plutonium oxalate. Using counting data from two concentric rings of 3 He detectors, corrections are made for the effects that water has on the coincidence neutron count rate. Batches of plutonium oxalate varying from 750 to 1000 g of plutonium and from 34 to 54% water are assayed with an average accuracy of +-3%

  5. Inhibition of crystallization of calcium oxalate by the extraction of Tamarix gallica L.

    Science.gov (United States)

    Bensatal, Ahmed; Ouahrani, M R

    2008-12-01

    The main objective is to study the inhibitor effect of acid fraction of the extract of Tamarix gallica L on the crystallization of calcium oxalate. The extract of Tamarix gallica L is very rich by acid compounds that are used as an inhibitor of nephrolithiasis (calcium oxalate). Our study of the calcium oxalate crystallization is based on the model of turbidimetry by means of a spectrophotometer. The calcium oxalate formation is induced by the addition of oxalate solutions of sodium and of calcium chloride. The addition of inhibitor with various concentrations enabled us to give information on the percentage of inhibition. The comparison between the turbidimetric slopes with and without inhibitor gives the effectiveness of inhibitor for the acid fraction. By comparing the photographs of with and without inhibitor, we concluded that the extract of Tamarix gallica L acts at the stage of growth. The acid fraction of the extract of Tamarix gallica L gives an activity remarkable in the formation of urinary lithiasis (calcium oxalate); this effectiveness is due to the presence of functions of acid.

  6. Growth and characterization of Sm3+ doped cerium oxalate single crystals

    Directory of Open Access Journals (Sweden)

    Minu Mary C

    2016-07-01

    Full Text Available Single crystals of Sm3+ doped cerium oxalate decahydrate were synthesized using single diffusion gel technique and the conditions influencing the size, morphology, nucleation density and quality of the crystals were optimized. Highly transparent single crystals of average size 3 mm × 2 mm × 1 mm with well-defined hexagonal morphology were grown during a time period of two weeks. X-ray powder diffraction analysis revealed that the grown crystals crystallize in the monoclinic system with space group P21/c as identical with the pure cerium oxalate. The various functional groups of the oxalate ligand and the water of crystallization were identified by Fourier transform infrared spectroscopy. The photoluminescence spectrum of the Sm3+ doped cerium oxalate indicated that the Sm3+ ions are optically active in the cerium oxalate matrix. The crystal has a strong and efficient orange red emission with a wavelength peak at 595 nm and hence can be effectively used for optical amplification. Microhardness measurements of the crystal revealed that they belong to the soft material category.

  7. Corrosion and impedance studies on magnesium alloy in oxalate solution

    Energy Technology Data Exchange (ETDEWEB)

    Fekry, A.M., E-mail: hham4@hotmail.com [Chemistry Department, Faculty of Science, Cairo University, Gamaa Street, Giza 12613 (Egypt); Tammam, Riham H. [Chemistry Department, Faculty of Science, Cairo University, Gamaa Street, Giza 12613 (Egypt)

    2011-06-15

    Highlights: > Corrosion behavior of AZ91E alloy was investigated in 0.1 M Na{sub 2}C{sub 2}O{sub 4} containing different additives as Br{sup -}, Cl{sup -} or Silicate. > The corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na{sub 2}C{sub 2}O{sub 4}). This was confirmed by scanning electron microscope (SEM) observations. > For the other added ions Br{sup -} or Cl{sup -}, the corrosion rate is higher than the blank. - Abstract: Corrosion behavior of AZ91E alloy was investigated in oxalate solution using potentiodynamic polarization and electrochemical impedance measurements (EIS). The effect of oxalate concentration was studied, where the corrosion rate increases with increasing oxalate concentration. The effect of added ions (Br{sup -}, Cl{sup -} or SiO{sub 3}{sup 2-}) on the electrochemical behavior of magnesium alloy in 0.1 M Na{sub 2}C{sub 2}O{sub 4} solution at 298 K, was investigated. It was found that the corrosion rate of 0.1 M oxalate solution containing silicate ion is lower than the blank (0.1 M Na{sub 2}C{sub 2}O{sub 4}). This was confirmed by scanning electron microscope (SEM) observations. However, for the other added ions Br{sup -} or Cl{sup -}, the corrosion rate is higher than the blank.

  8. Precipitation of plutonium (III) oxalate and calcination to plutonium oxide

    International Nuclear Information System (INIS)

    Esteban, A.; Orosco, E.H.; Cassaniti, P.; Greco, L.; Adelfang, P.

    1989-01-01

    The plutonium based fuel fabrication requires the conversion of the plutonium nitrate solution from nuclear fuel reprocessing into pure PuO2. The conversion method based on the precipitation of plutonium (III) oxalate and subsequent calcination has been studied in detail. In this procedure, plutonium (III) oxalate is precipitated, at room temperature, by the slow addition of 1M oxalic acid to the feed solution, containing from 5-100 g/l of plutonium in 1M nitric acid. Before precipitation, the plutonium is adjusted to trivalent state by addition of 1M ascorbic acid in the presence of an oxidation inhibitor such as hydrazine. Finally, the precipitate is calcinated at 700 deg C to obtain PuO2. A flowsheet is proposed in this paper including: a) A study about the conditions to adjust the plutonium valence. b) Solubility data of plutonium (III) oxalate and measurements of plutonium losses to the filtrate and wash solution. c) Characterization of the obtained products. Plutonium (III) oxalate has several potential advantages over similar conversion processes. These include: 1) Formation of small particle sizes powder with good pellets fabrication characteristics. 2) The process is rather insensitive to most process variables, except nitric acid concentration. 3) Ambient temperature operations. 4) The losses of plutonium to the filtrate are less than in other conversion processes. (Author) [es

  9. Flow injection analysis-flame atomic absorption spectrometry system for indirect determination of sulfite after on-line reduction of solid-phase manganese (IV) dioxide reactor.

    Science.gov (United States)

    Zare-Dorabei, Rouholah; Boroun, Shokoufeh; Noroozifar, Meissam

    2018-02-01

    A new and simple flow injection method followed by atomic absorption spectrometry was developed for indirect determination of sulfite. The proposed method is based on the oxidation of sulfite to sulphate ion using solid-phase manganese dioxide (30% W/W suspended on silica gel beads) reactor. MnO 2 will be reduced to Mn(II) by sample injection in to the column under acidic carrier stream of HNO 3 (pH 2) with flow rate of 3.5mLmin -1 at room temperature. Absorption measurement of Mn(II) which is proportional to the concentration of sulfite in the sample was carried out by atomic absorption spectrometry. The calibration curve was linear up to 25mgL -1 with a detection limit (DL) of 0.08mgL -1 for 400µL injection sample volume. The presented method is efficient toward sulfite determination in sugar and water samples with a relative standard deviation (RSD) less than 1.2% and a sampling rate of about 60h -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Arthritis associated with calcium oxalate crystals in an anephric patient treated with peritoneal dialysis

    International Nuclear Information System (INIS)

    Rosenthal, A.; Ryan, L.M.; McCarty, D.J.

    1988-01-01

    The authors report a case of calcium oxalate arthropathy in a woman undergoing intermittent peritoneal dialysis who was not receiving pharmacologic doses of ascorbic acid. She developed acute arthritis, with calcium oxalate crystals in Heberden's and Bouchard's nodes, a phenomenon previously described in gout. Intermittent peritoneal dialysis may be less efficient than hemodialysis in clearing oxalate, and physicians should now consider calcium oxalate-associated arthritis in patients undergoing peritoneal dialysis who are not receiving large doses of ascorbic acid

  11. Nitrates and Nitrites in the Treatment of Ischemic Cardiac Disease

    Science.gov (United States)

    Nossaman, Vaughn E.; Nossaman, Bobby D.; Kadowitz, Philip J.

    2010-01-01

    The organic nitrite, amyl of nitrite, was initially used as a therapeutic agent in the treatment of angina pectoris in 1867, but was replaced over a decade later by the organic nitrate, nitroglycerin (NTG), due to the ease of administration and longer duration of action. The administration of organic nitrate esters, such as NTG, continues to be used in the treatment of angina pectoris and heart failure during the birth of modern pharmacology. The clinical effectiveness is due to vasodilator activity in large veins and arteries through an as yet unidentified method of delivering nitric oxide (NO), or a NO-like compound to vascular smooth muscle cells. The major drawback with NTG administration is the rapid development of tolerance; and with amyl of nitrite, the duration and route of administration. Although amyl of nitrite are no longer used in the treatments of hypertension or ischemic heart disease, the nitrite anion has recently been discovered to possess novel pharmacologic actions such as modulating hypoxic vasodilation and providing cytoprotection in ischemia-reperfusion injury. Although the actions of these two similar chemical classes (nitrites and organic nitrates) have often been considered to be alike, we still do not understand their mechanism of action. However, the recent discovery that the nitrite anion, derived from either sodium nitrite or an intermediate NTG form, may act as a storage form for NO and provides support for investigating the use of these agents in the treatment of ischemic cardiovascular states. We review what is presently known about the use of nitrites and nitrates, the potential uses of these agents, and their mechanisms of action. PMID:20539102

  12. Dietary nitrate and nitrite: Benefits, risks, and evolving perceptions.

    Science.gov (United States)

    Bedale, Wendy; Sindelar, Jeffrey J; Milkowski, Andrew L

    2016-10-01

    Consumers have an illogical relationship with nitrite (and its precursor, nitrate) in food. Despite a long history of use, nitrite was nearly banned from use in foods in the 1970s due to health concerns related to the potential for carcinogenic nitrosamine formation. Changes in meat processing methods reduced those potential risks, and nitrite continued to be used in foods. Since then, two opposing movements continue to shape how consumers view dietary nitrate and nitrite. The discovery of the profound physiological importance of nitric oxide led to the realization that dietary nitrate contributes significantly to the nitrogen reservoir for nitric oxide formation. Numerous clinical studies have also demonstrated beneficial effects from dietary nitrate consumption, especially in vascular and metabolic health. However, the latest wave of consumer sentiment against food additives, the clean-label movement, has renewed consumer fear and avoidance of preservatives, including nitrite. Education is necessary but may not be sufficient to resolve this disconnect in consumer perception. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Methaemoglobinaemia due to amyl nitrite inhalation: a case report.

    Science.gov (United States)

    Machabert, R; Testud, F; Descotes, J

    1994-05-01

    Methaemoglobinaemia is a potential toxic effect of aliphatic nitrites which are increasingly abused by male homosexuals and drug addicts because of marked vasodilating properties ('poppers'). In most instances, severe complications were described following the ingestion of large quantities of amyl, butyl or isobutyl nitrites. A deficiency in NADH-dependent haemoglobin reductase in some patients has been noted. This is the first report of symptomatic methaemoglobinaemia following the inhalation of amyl nitrite.

  14. Mitochondria recycle nitrite back to the bioregulator nitric monoxide

    International Nuclear Information System (INIS)

    Nohl, H.; Staniek, K.; Sobhian, B.; Bahrami, S.; Redl, H.; Kozlov, A.V.

    2000-01-01

    Nitric monoxide (NO) exerts a great variety of physiological functions. L-Arginine supplies amino groups which are transformed to NO in various NO-synthase-active isoenzyme complexes. NO-synthesis is stimulated under various conditions increasing the tissue of stable NO-metabolites. The major oxidation product found is nitrite. Elevated nitrite levels were reported to exist in a variety of diseases including HIV, reperfusion injury and hypovolemic shock. Denitrifying bacteria such as Paracoccus denitrificans have a membrane bound set of cytochromes (cyt cd 1 , cyt bc) which were shown to be involved in nitrite reduction activities. Mammalian mitochondria have similar cytochromes which form part of the respiratory chain. Like in bacteria quinols are used as reductants of these types of cytochromes. The observation of one-e - divergence from this redox-couple to external dioxygen made us to study whether this site of the respiratory chain may also recycle nitrite back to its bioactive form NO. Thus, the aim of the present study was therefore to confirm the existence of a reductive pathway which reestablishes the existence of the bioregulator NO from its main metabolite NO 2 - . Our results show that respiring mitochondria readily reduce added nitrite to NO which was made visible by nitrosylation of deoxyhemoglobin. The adduct gives characteristic triplet-ESR-signals. Using inhibitors of the respiratory chain for chemical sequestration of respiratory segments we were able to identify the site where nitrite is reduced. The results confirm the ubiquinone/cyt bc 1 couple as the reductant site where nitrite is recycled. The high affinity of NO to the heme-iron of cytochrome oxidase will result in an impairment of mitochondrial energy-production. ''Nitrite tolerance'' of angina pectoris patients using NO-donors may be explained in that way. (author)

  15. Enzymatic oxalic acid regulation correlated with wood degradation in four brown-rot fungi

    Science.gov (United States)

    Anne Christine Steenkjær Hastrup; Frederick Green III; Patricia K. Lebow; Bo Jensen

    2012-01-01

    Oxalic acid is a key component in the initiation of brown-rot decay and it has been suggested that it plays multiple roles during the degradation process. Oxalic acid is accumulated to varying degrees among brown-rot fungi; however, details on active regulation are scarce. The accumulation of oxalic acid was measured in this study from wood degraded by the four brown-...

  16. (Di­methyl­phosphor­yl)methanaminium hydrogen oxalate–oxalic acid (2/1)

    Science.gov (United States)

    Bialek, Sebastian; Clemens, Rebecca; Reiss, Guido J.

    2014-01-01

    The reaction of (di­methyl­phosphor­yl)methanamine (dpma) with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4 −·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-mol­ecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16°) whereas the oxalic acid molecule shows a significantly smaller bend angle (∼7°). In the crystal, the components are connected by strong O—H⋯O and much weaker N—H⋯O hydrogen bonds, leading to the formation of layers extending parallel to (001). The structure was refined from a racemically twinned crystal with twin components in an approximate 1:1 ratio. PMID:24765013

  17. Estimation of nitrite in source-separated nitrified urine with UV spectrophotometry.

    Science.gov (United States)

    Mašić, Alma; Santos, Ana T L; Etter, Bastian; Udert, Kai M; Villez, Kris

    2015-11-15

    Monitoring of nitrite is essential for an immediate response and prevention of irreversible failure of decentralized biological urine nitrification reactors. Although a few sensors are available for nitrite measurement, none of them are suitable for applications in which both nitrite and nitrate are present in very high concentrations. Such is the case in collected source-separated urine, stabilized by nitrification for long-term storage. Ultraviolet (UV) spectrophotometry in combination with chemometrics is a promising option for monitoring of nitrite. In this study, an immersible in situ UV sensor is investigated for the first time so to establish a relationship between UV absorbance spectra and nitrite concentrations in nitrified urine. The study focuses on the effects of suspended particles and saturation on the absorbance spectra and the chemometric model performance. Detailed analysis indicates that suspended particles in nitrified urine have a negligible effect on nitrite estimation, concluding that sample filtration is not necessary as pretreatment. In contrast, saturation due to very high concentrations affects the model performance severely, suggesting dilution as an essential sample preparation step. However, this can also be mitigated by simple removal of the saturated, lower end of the UV absorbance spectra, and extraction of information from the secondary, weaker nitrite absorbance peak. This approach allows for estimation of nitrite with a simple chemometric model and without sample dilution. These results are promising for a practical application of the UV sensor as an in situ nitrite measurement in a urine nitrification reactor given the exceptional quality of the nitrite estimates in comparison to previous studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. A Novel Method for Fabricating Double Layers Porous Anodic Alumina in Phosphoric/Oxalic Acid Solution and Oxalic Acid Solution

    Directory of Open Access Journals (Sweden)

    Yanfang Xu

    2016-01-01

    Full Text Available A novel method for fabricating ordered double layers porous anodic alumina (DL-PAA with controllable nanopore size was presented. Highly ordered large pore layer with interpore distance of 480 nm was fabricated in phosphoric acid solution with oxalic acid addition at the potential of 195 V and the small pore layer was fabricated in oxalic acid solution at the potential from 60 to 100 V. Experimental results show that the thickness of large pore layer is linearly correlative with anodizing time, and pore diameter is linearly correlative with pore widening time. When the anodizing potential in oxalic acid solution was adjusted from 60 to 100 V, the small pore layers with continuously tunable interpore distance from 142 to 241 nm and pore density from 1.94×109 to 4.89×109 cm−2 were obtained. And the interpore distance and the pore density of small pore layers are closely correlative with the anodizing potential. The fabricated DL-PAA templates can be widely utilized for fabrication of ordered nanomaterials, such as superhydrophobic or gecko-inspired adhesive materials and metal or semiconductor nanowires.

  19. Nitrate and nitrite in biology, nutrition and therapeutics

    NARCIS (Netherlands)

    Lundberg, J.O.; van Faassen, E.E.H.; Gladwin, M.T.; Ahluwalia, A.; Benjamin, N.

    2009-01-01

    Inorganic nitrate and nitrite from endogenous or dietary sources are metabolized in vivo to nitric oxide (NO) and other bioactive nitrogen oxides. The nitrate-nitrite-NO pathway is emerging as an important mediator of blood flow regulation, cell signaling, energetics and tissue responses to hypoxia.

  20. Electrochemical oxidation of nitrite on nanodiamond powder electrode

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.H.; Zang, J.B.; Wang, Y.H.; Bian, L.Y. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2008-03-10

    Nanodiamond (ND) powder electrodes were fabricated and the electrochemical properties were investigated in the solution containing nitrite in this article. This electrode exhibits substantial catalytic ability toward the oxidation of nitrite anions. The electrochemical oxidation mechanism of nitrite on the ND powder electrode is discussed. The oxidation of NaNO{sub 2} is a two-electron transfer process. The electrode reaction rate constant k is estimated to be 2.013 x 10{sup -4} cm/s and (1 - {alpha})n{sub {alpha}} is 0.1643. The peak current increases linearly with the rising of the concentration of NaNO{sub 2}. (author)

  1. Physiology and interaction of nitrate and nitrite reduction in Staphylococcus carnosus.

    OpenAIRE

    Neubauer, H; Götz, F

    1996-01-01

    Staphylococcus carnosus reduces nitrate to ammonia in two steps. (i) Nitrate was taken up and reduced to nitrite, and nitrite was subsequently excreted. (ii) After depletion of nitrate, the accumulated nitrite was imported and reduced to ammonia, which again accumulated in the medium. The localization, energy gain, and induction of the nitrate and nitrite reductases in S. carnosus were characterized. Nitrate reductase seems to be a membrane-bound enzyme involved in respiratory energy conserva...

  2. Influence of oxalic acid on the dissolution kinetics of manganese oxide

    Science.gov (United States)

    Godunov, E. B.; Artamonova, I. V.; Gorichev, I. G.; Lainer, Yu. A.

    2012-11-01

    The kinetics and electrochemical processes of the dissolution of manganese oxides with various oxidation states in sulfuric acid solutions containing oxalate ion additives is studied under variable conditions (concentration, pH, temperature). The parameters favoring a higher degree of the dissolution of manganese oxides in acidic media are determined. The optimal conditions are found for the dissolution of manganese oxides in acidic media in the presence of oxalate ions. The mechanism proposed for the dissolution of manganese oxides in sulfuric acid solutions containing oxalic acid is based on the results of kinetic and electrochemical studies. The steps of the dissolution mechanism are discussed.

  3. ENHANCED CHEMICAL CLEANING: EFFECTIVENESS OF THE UV LAMP TO DECOMPOSE OXALATES

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E.; Huff, T.; Sudduth, C.

    2010-01-19

    Enhanced Chemical Cleaning is a new process scheduled to begin cleaning Savannah River Site High Level Waste Tanks in 2012. It is an improvement over the current chemical cleaning method, in that it minimizes downstream impacts on the High Level Waste System. It is based on a state of the art scale removal process used on the secondary side of nuclear power plants, with modifications to accommodate the unique constraints created by the tanks. Both Enhanced Chemical Cleaning and the scale removal process are founded on dissolving metal oxides/hydroxides using oxalic acid, with subsequent oxalate decomposition via hydroxylation using ozone or peroxide, and UV light as a catalyst. A divergence Enhanced Chemical Cleaning has from nuclear power scale removal is the significantly increased solids concentration during oxalate decomposition. These solids can limit the ability of the UV light to create hydroxyl radicals, either by limiting the ability of the light to penetrate through the solution, or by increasing the fouling rate on the UV light. Both will decrease the overall catalytic effectiveness, thereby decreasing the concentration of formed hydroxyl radicals. The hydroxyl radicals are the driving force behind the oxalate decomposition. To understand the impact of increased solids, testing was performed using a medium pressure UV light inside an ozone supplied Oxalate Decomposition Reactor. Using a dissolved metal sludge simulant with an initial oxalate concentration greater than 12,000 ppm, and an initial pH of about 2.0, the spent acid solution was recirculated through the reactor, while the UV light was allowed to foul. For the first few hours, the oxalate decomposition rate was about 1,300 ppm/hour. After about 3 hours, enough time for the UV lamp to foul, the oxalate decomposition rate decreased to about 500 ppm/hour. The decomposition rate then remained roughly constant for the next 16 hours. Overall, testing showed that the oxalate destruction rate decreased

  4. Nitrates and nitrites intoxications’ management

    Directory of Open Access Journals (Sweden)

    Alexandra Trif

    2007-12-01

    Full Text Available The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers, circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride, factors that determine high nitrates accumulation in fodders despite optimal fertilization (factors related to the plants, soil, clime, harvest methods, storage, agrotechnical measures, nitrates/nitrites toxicity (over 45 ppm nitrates in drinking water, over 0.5 g nitrate/100 g D.M fodder/diet, the factors that influence nitrates/nitrites toxicity ( species, age, rate of feeding, diet balance especially energetically, pathological effects and symptoms (irritation and congestions on digestive tract, resulting diarrhoea, transformation of hemoglobin into methemoglobin determining severe respiratory insufficiency, vascular collapse, low blood pressure inthe acute nitrates intoxication; hypotiroidism, hypovitaminosis A, reproductive disturbances(abortion, low rate of fertility, dead born offspring, diarrhoea and/or respiratory insufficiency in new born e.g. calves, immunosuppression, decrease of milk production in chronic intoxication. There were presented some suggestions concerning management practices to limit nitrate intoxication (analyze of nitrates/nitrites in water and fodders, good management of the situation of risk ,e .g. dilution of the diet with low nitrate content fodders, feeding with balanced diet in energy, protein, minerals and vitamins, accommodation to high nitrate level diet, avoid grazing one week after a frost period, avoid feeding chop green fodders stored a couple of days, monitoring of health status of animals fed with fodders containing nitrates at risk level, a.o..

  5. Controls of nitrite oxidation in ammonia-removing biological air filters

    DEFF Research Database (Denmark)

    Juhler, Susanne; Ottosen, Lars Ditlev Mørck; Nielsen, Lars Peter

    2008-01-01

    in accumulation of nitrate rather than nitrite and a significant decline in pH. As a consequence, ammonia is removed more efficiently, but heterotrophic oxidation of odorous compounds might be inhibited.  To identify the controlling mechanisms of nitrite oxidation, full-scale biological air filters were...... activity resulting in a lowered pH and thus a decreased FA concentration, promoting further growth of NOB. Yet, in some cases a situation with a nitrate-to-nitrite ratio of 1 and moderate pH remained stable even under varying air load and water supply, suggesting that additional mechanisms were involved......In biological air filters ammonia is removed due to the action of Ammonia Oxidizing Bacteria (AOB) resulting in nitrite accumulation exceeding 100 mM. Among filters treating exhaust air from pig facilities successful establishment of Nitrite Oxidizing Bacteria (NOB) sometimes occurs, resulting...

  6. Metabolic fates and effects of nitrite in brown trout under normoxic and hypoxic conditions: blood and tissue nitrite metabolism and interactions with branchial NOS, Na+/K+-ATPase and hsp70 expression

    DEFF Research Database (Denmark)

    Jensen, Frank Bo; Gerber, Lucie; Hansen, Marie Niemann

    2015-01-01

    were higher in hypoxia than normoxia, suggesting increased NOS activity. Nitrite exposure strongly elevated nitrite concentrations in plasma, erythrocytes, heart tissue and white muscle, which was associated with an extensive metabolism of nitrite to nitrate and to iron-nitrosylated and S......Nitrite secures essential nitric oxide (NO) bioavailability in hypoxia at low endogenous concentrations, whereas it becomes toxic at high concentrations. We exposed brown trout to normoxic and hypoxic water in the absence and presence of added ambient nitrite to decipher the cellular metabolism...... and effects of nitrite at basal and elevated concentrations under different oxygen regimes. We also tested hypotheses concerning the influence of nitrite on branchial nitric oxide synthase (NOS), Na+/K+-ATPase (nka) and heat shock protein (hsp70) mRNA expression. Basal plasma and erythrocyte nitrite levels...

  7. Precipitation stripping of neodymium from carboxylate extractant with aqueous oxalic acid solutions

    International Nuclear Information System (INIS)

    Konishi, Yasuhiro; Asai, Satoru; Murai, Tetuya

    1993-01-01

    This paper describes a precipitation stripping method in which neodymium ions are stripped from carboxylate extractant in organic solvent and simultaneously precipitated with aqueous oxalic acid solution. For the single-stage process, a quantitative criterion for precipitating oxalate powders was derived theoretically, and stripping experiments were done under the precipitation conditions. The resultant precipitates were neodymium oxalate, which is completely free from contamination by the carboxylate extractant and the organic solvent. The overall rate of stripping was controlled by the transfer of neodymium carboxylate in the organic solution, indicating that the presence of oxalic acid in the aqueous phase has no effect on the stripping rate. These findings demonstrate the feasibility of combining the conventional stripping and precipitation stages in a solvent extraction process for separation and purification of rare earths

  8. Methanol as electron donor for thermophilic biological sulfate and sulfite reduction

    OpenAIRE

    Weijma, J.

    2000-01-01

    Sulfur oxyanions (e.g. sulfate, sulfite) can be removed from aqueous waste- and process streams by biological reduction with a suitable electron donor to sulfide, followed by partial chemical or biological oxidation of sulfide to elemental sulfur. The aim of the research described in this thesis was to make this biological process more broadly applicable for desulfurization of flue-gases and ground- and wastewaters by using the cheap chemical methanol as electron donor for the reduct...

  9. [Evaluation of nitrites and nitrates food intake in the students' group].

    Science.gov (United States)

    Wawrzyniak, Agata; Hamułka, Jadwiga; Pankowska, Iwona

    2010-01-01

    The aim of study was to determine the intake of nitrites and nitrates in daily food rations of the students' group in 2008 using 3-day dietary food records method and literature mean values of nitrates and nitrites in food products. Intakes of these compounds were calculated and compared to acceptable daily intake (ADI). The average intake of nitrites was 1.7 mg NaNO2/per person/day (28.0% of ADI), nitrates 77.3 mg NaNO3/per person/day that means 25.4% of ADI. The largest nitrites food intake was noticed for meat products supplied 56.5% of nitrites and cereals (20%). Whereas vegetables and their products supplied 76.1% of nitrates: potatoes 17.1%, cabbage 15.5%, beetroots 13.7%. Calculated nitrites intake for men was 2.4 higher than for women. There were no significant differences of nitrates intake between men and women groups.

  10. Effect of Dry Red Grape Pomace as a Nitrite Substitute on the Microbiological and Physicochemical Properties and Residual Nitrite of Dry-cured Sausage

    OpenAIRE

    Fatemeh Riazi; Fariba Zeynali; Ebrahim Hoseini; Homa Behmadi

    2016-01-01

    Background and Objectives: Sodium nitrite and potassium nitrite have been traditionally used for inhibition of Clostridium botulinum and also as an agent to stabilize the color of meat products; however, usage of these additives at high levels could lead to toxicity and cancer originating from the formation of nitrosamines. Nowadays, application of natural preservatives in order to reduce the nitrite content in meat products is increasing. Thus, we used dry red grape pomace (DRGP) as a natura...

  11. Structural diversity of the lanthanide oxalates: Condensation of neodymium oxygen polyhedra under hydrothermal conditions

    International Nuclear Information System (INIS)

    Mer, A.; Rivenet, M.; Abraham, F.; De Almeida, L.; Grandjean, S.

    2013-01-01

    New neodymium hydroxo-oxalate and oxalate [Nd 6 (H 2 O) 6 (C 2 O 4 ) 7 (OH) 4 ].4H 2 O (1) and [Nd 2 (H 2 O) 4 (C 2 O 4 ) 3 ].2H 2 O (2) were synthesized by hydrothermal reaction at 150 C between neodymium nitrate and oxalic acid solutions at pH = 10-11 obtained by adding various monoamines. The structures were determined from single-crystal X-ray diffraction data. The two compounds crystallize in the monoclinic system with space group P21/c and a = 17.4384 (11), b = 8.1717 (5), c = 12.9929 (7), β = 94.66 (1) degrees, V = 1845.38 (19) (Angstroms) 3 , Z = 2 for 1 and a = 9.8249 (2) Angstroms, b = 8.2487 (2) Angstroms, c = 10.1911 (3) Angstroms, β = 99.09 (1), V = 815.53 (4) (Angstroms) 3 , Z = 2 for 2. Full matrix least-squares refinement yielded R1 = 0.0365 and 0.0267 for 6033 and 3382 independent reflections for 1 and 2 respectively. In 2, the three-dimensional neodymium oxalate arrangement results from dimeric units of edge shared NdO 9 polyhedra connected through oxalate ions acting as bis-bidentate. In 1, the neodymium atoms are connected through μ2-OH and μ3-OH ions to form a hexa-nuclear inorganic core [Nd 6 (OH) 4 (H 2 O) 6 ] with an un-precedently reported geometry leading to a hexa-nuclear polyhedra block. The blocks are connected through an O-O bridge involving two oxygen atoms of two oxalate ions to build a centipede-like ribbon. The ribbons are further connected through oxalate ions to form a three dimensional neodymium oxalate arrangement. In 1, oxalates adopt four distinct bridging modes of coordination, μ2, μ3, μ4 and μ5. (authors)

  12. Removal of plutonium from nitric acid-oxalic acid solutions using anion exchange method

    International Nuclear Information System (INIS)

    Kasar, U.M.; Pawar, S.M.; Joshi, A.R.

    1999-01-01

    An anion exchange method using Amberlyst A-26 (MP) resin was developed for removal of Pu from nitric acid-oxalic acid solutions without destroying oxalate. The method consists of sorption of Pu(IV) on Amberlyst A-26, a macroporous anion exchange resin, from nitric acid-oxalic acid medium in the presence of Al(NO 3 ) 3 . Pu(IV) breakthrough capacity of Amberlyst A-26 using synthetic feed solution was determined. (author)

  13. In-cloud oxalate formation in the global troposphere: a 3-D modeling study

    Directory of Open Access Journals (Sweden)

    S. Myriokefalitakis

    2011-06-01

    Full Text Available Organic acids attract increasing attention as contributors to atmospheric acidity, secondary organic aerosol mass and aerosol hygroscopicity. Oxalic acid is globally the most abundant dicarboxylic acid, formed via chemical oxidation of gas-phase precursors in the aqueous phase of aerosols and droplets. Its lifecycle and atmospheric global distribution remain highly uncertain and are the focus of this study. The first global spatial and temporal distribution of oxalate, simulated using a state-of-the-art aqueous-phase chemical scheme embedded within the global 3-dimensional chemistry/transport model TM4-ECPL, is here presented. The model accounts for comprehensive gas-phase chemistry and its coupling with major aerosol constituents (including secondary organic aerosol. Model results are consistent with ambient observations of oxalate at rural and remote locations (slope = 1.16 ± 0.14, r2 = 0.36, N = 114 and suggest that aqueous-phase chemistry contributes significantly to the global atmospheric burden of secondary organic aerosol. In TM4-ECPL most oxalate is formed in-cloud and less than 5 % is produced in aerosol water. About 62 % of the oxalate is removed via wet deposition, 30 % by in-cloud reaction with hydroxyl radical, 4 % by in-cloud reaction with nitrate radical and 4 % by dry deposition. The in-cloud global oxalate net chemical production is calculated to be about 21–37 Tg yr−1 with almost 79 % originating from biogenic hydrocarbons, mainly isoprene. This condensed phase net source of oxalate in conjunction with a global mean turnover time against deposition of about 5 days, maintain oxalate's global tropospheric burden of 0.2–0.3 Tg, i.e. 0.05–0.1 Tg-C that is about 5–9 % of model-calculated water soluble organic carbon burden.

  14. Spectrofluorometric and Molecular Modeling Studies on Binding of Nitrite Ion with Bovine Hemoglobin: Effect of Nitrite Ion on Amino Acid Residues

    Science.gov (United States)

    Madrakian, T.; Bagheri, H.; Afkhami, A.

    2015-05-01

    The interaction between nitrite ion and bovine hemoglobin was investigated by a spectrofluorometric technique. The experimental results indicated that the interaction causes a static quenching of the fluorescence of bovine hemoglobin, that the binding reaction is spontaneous, and that H-bonding interactions play a major role in binding of this ion to bovine hemoglobin. The formation constant for this interaction was calculated. Based on Förster's theory of nonradiative energy transfer, the binding distance between this ion and bovine hemoglobin was determined. Furthermore, the interaction of nitrite ion with tyrosine and tryptophan was investigated with synchronous fluorescence. There was no significant shift of the maximum emission wavelength with interactions of the mentioned ion with bovine hemoglobin, which implies that interaction of nitrite ion with bovine hemoglobin does not affect the microenvironment around the tryptophan and tyrosine residues. Furthermore, the effect of nitrite ion on amino acid residues of bovine hemoglobin was studied by a molecular docking technique.

  15. The Reaction of Oxy Hemoglobin with Nitrite

    DEFF Research Database (Denmark)

    Hathazi, Denisa; Scurtu, Florina; Bischin, Cristina

    2018-01-01

    The autocatalytic reaction between nitrite and the oxy form of globins involves free radicals. For myoglobin (Mb), an initial binding of nitrite to the iron-coordinated oxygen molecule was proposed; the resulting ferrous-peroxynitrate species was not detected, but its decay product, the high...... to a simple kinetic model involving a transient met-aqua form, in contrast to the ferryl detected in the case of Mb in a similar reaction sequence. These data are in line with a previous observation of a transient accumulation of ferryl Hb under auto-catalytic conditions at much lower concentrations......-peroxynitrate. Density functional theory (DFT) calculations support this latter assignment. The reaction allows for differentiating between the reactivities of various chemically modified hemoglobins, including candidates for blood substitutes. Polymerization of hemoglobin slows the nitrite-induced oxidation, in sharp...

  16. Determination of nitrite, nitrate and total nitrogen in vegetable samples

    Directory of Open Access Journals (Sweden)

    Manas Kanti Deb

    2007-04-01

    Full Text Available Yellow diazonium cation formed by reaction of nitrite with 6-amino-1-naphthol-3-sulphonic acid is coupled with β-naphthol in strong alkaline medium to yield a pink coloured azo dye. The azo-dyes shows absorption maximum at 510 nm with molar absorptivity of 2.5 ×104 M-1 cm-1. The dye product obeys Beer's law (correlation coefficient = 0.997, in terms of nitrite concentration, up to 2.7 μg NO2 mL-1. The above colour reaction system has been applied successfully for the determination of nitrite, nitrate and total nitrogen in vegetable samples. Unreduced samples give direct measure for nitrite whilst reduction of samples by copperized-cadmium column gives total nitrogen content and their difference shows nitrate content in the samples. Variety of vegetables have been tested for their N-content (NO2-/NO3-/total-N with % RSD ranging between 1.5 to 2.5 % for nitrite determination. The effects of foreign ions in the determination of the nitrite, nitrate, and total nitrogen have been studied. Statistical comparison of the results with those of reported method shows good agreement and indicates no significant difference in precision.

  17. Nitrites and nitrates in the human diet: Carcinogens or beneficial hypotensive agents?

    Science.gov (United States)

    Butler, Anthony

    2015-06-05

    The presence of nitrite in the human diet was thought to constitute a hazard as secondary nitrosamines are known to cause gastric cancers. Recent publications on the physiology of serum nitrite have been consulted. Nitrite is added to some foodstuffs as an antibotulinum agent. The epidemiological evidence that nitrite causes gastric ulcers is weak. On the other hand, evidence that the presence of nitrite in serum lowers blood pressure is strong. This allows us to explain why a Tang dynasty treatment for angina, given in a Dunhuang medical manuscript, can be successful. The presence of nitrite in food is free of danger and a diet high in nitrate is beneficial to the health. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Determination of Food Oxalates Using Silica–Titania Xerogel Modified with Eriochrome Cyanine R

    Directory of Open Access Journals (Sweden)

    Maria A. Morosanova

    2018-03-01

    Full Text Available The interaction of silica–titania xerogel with triphenylmethane dyes (pyrocatechol violet, chrome azurol S, eriochrome cyanine R has been investigated to create a new sensor material for solid phase spectrophotometric determination of food oxalates. The complex forming reaction between xerogel incorporated titanium(IV and triphenylmethane dyes has been studied; half-reaction periods, complex composition, equilibrium constants, and xerogel sorption capacity have been calculated for each dye. Eriochrome cyanine R (ECR is characterized by the shortest half-reaction period, the smallest equilibrium constant, and the greatest capacity; it has been chosen for the sensor material construction because titanium(IV-ECR complex is formed faster and can be destroyed easier than other studied complexes. The interaction of this sensor material with oxalates has been described: the presence of oxalates causes sensor material discoloration and the absorbance is used as analytical signal. The analytical range is 35–900 mg/L (LOD 10.5 mg/L, n = 7. High concentrations of interfering inorganic anions, organic acids, and sucrose did not affect oxalate determination. Proposed solid phase spectrophotometric procedure has been successfully applied for the determination of oxalates in food samples (sorrel, spinach, parsley, ginger, and black pepper and the results are in good agreement with HPLC oxalate determination.

  19. Nitrite enhances liver graft protection against cold ischemia ...

    African Journals Online (AJOL)

    Amani Cherif-Sayadi

    2017-03-30

    Mar 30, 2017 ... cold ischemia reperfusion injury through a NOS ... oxidation and lipid peroxidation remained at low levels in both nitrite-treated groups when ... liver graft preservation [15]. ... nitrite activity is dependent on NO production but .... LiversT rat (n = 6) were flushed and preserved in IGL-1 solution ..... The nitrate-.

  20. Effects of potassium oxalate on knoop hardness of etch-and-rinse adhesives.

    Science.gov (United States)

    Silva, S M A; Malacarne-Zanon, J; Carvalho, R M; Alves, M C; De Goes, M F; Anido-Anido, A; Carrilho, M R

    2012-01-01

    The objective of this study was to determine whether the hardness of etch-and-rinse adhesives may be affected by the pretreatment of acid-etched dentin with potassium oxalate desensitizer. Unerupted human third molars were cut into crown segments by removing the occlusal enamel and roots. The pulp chamber of these crown segments was connected to a syringe barrel filled with phosphate-buffered saline so that the moisture of dentin was maintained during the bonding procedures. Three etch-and-rinse adhesives-two two-step systems (Adper Single Bond 2 [SB], One-Step [OS]) and one three-step system (Adper Scotchbond Multi-Purpose [MP])-were applied to acid-etched dentin that had been treated (experimental groups) or not (control groups) with potassium oxalate (BisBlock). The Knoop hardness (KHN) of adhesives was taken at different sites of the outer surface of the adhesive-bonded dentin. The KHN of the three tested adhesives applied to acid-etched dentin treated with potassium oxalate was significantly lower than that exhibited by the respective controls (not treated with oxalate; padhesive, the treatment with potassium oxalate reduced the adhesives' KHN (psystem exhibiting the lowest KHN compared with the MP and SB systems.

  1. Effect of animal and vegetable protein intake on oxalate excretion in idiopathic calcium stone disease.

    Science.gov (United States)

    Marangella, M; Bianco, O; Martini, C; Petrarulo, M; Vitale, C; Linari, F

    1989-04-01

    Oxalate excretion was measured in healthy subjects and idiopathic calcium stone-formers on dietary regimens which differed in the type and amount of protein allowed; 24-h urine collections were obtained from 41 practising vegetarians and 40 normal persons on a free, mixed, "mediterranean" diet. Twenty idiopathic calcium stone-formers were also studied while on two low calcium, low oxalate diets which differed in that animal protein was high in one and restricted in the other. Vegetarians had higher urinary oxalate levels than controls and although the calcium levels were markedly lower, urinary saturation with calcium/oxalate was significantly higher. This mild hypercalciuria was interpreted as being secondary to both a higher intake and increased fractional intestinal absorption of oxalate. Changing calcium stone-formers from a high to a low animal protein intake produced a significant decrease in calcium excretion but there was no variation in urinary oxalate. As a result, the decrease in calcium oxalate saturation was only marginal and not significant. It was concluded that dietary animal protein has a minimal effect on oxalate excretion. Mild hyperoxaluria of idiopathic calcium stone disease is likely to be intestinal in origin. Calcium stone-formers should be advised to avoid an excess of animal protein but the risks of a vegetable-rich diet should also be borne in mind.

  2. Oxalic acid biosynthesis is encoded by an operon in Burkholderia glumae

    Science.gov (United States)

    Although the biosynthesis of oxalic acid is known to occur in a number of bacteria, the mechanism(s) regulating its production remains largely unknown. To date, there is no report on the identification of an oxalic acid biosynthetic pathway gene from bacteria. In an attempt to identify such a gene...

  3. Electrochemical detection of nitrite based on the polythionine/carbon nanotube modified electrode

    International Nuclear Information System (INIS)

    Deng, Chunyan; Chen, Jinzhuo; Nie, Zhou; Yang, Minghui; Si, Shihui

    2012-01-01

    In this paper, thionine was electro-polymerized onto the surface of carbon nanotube (CNT)-modified glassy carbon (GC) to fabricate the polythionine (PTH)/CNT/GC electrode. It was found that the electro-reduction current of nitrite was enhanced greatly at the PTH/CNT/GC electrode. It may be demonstrated that PTH was used as a mediator for electrocatalytic reduction of nitrite, and CNTs as an excellent nanomaterial can improve the electron transfer between the electrode and nitrite. Therefore, based on the synergic effect of PTH and CNTs, the PTH/CNT/GC electrode was employed to detect nitrite, and the high sensitivity of 5.81 μA mM −1 , and the detection limit of 1.4 × 10 −6 M were obtained. Besides, the modified electrode showed an inherent stability, fast response time, and good anti-interference ability. These suggested that the PTH/CNT/GC electrode was favorable and reliable for the detection of nitrite. - Highlights: ► Polythionine (PTH) was used as a mediator for electrocatalytic reduction of nitrite. ► Carbon nanotubes (CNTs) improve electron transfer between the electrode and nitrite. ► The PTH/CNT/glassy carbon electrode showed excellent nitrite detection performance.

  4. Viscosities of oxalic acid and its salts in water and binary aqueous ...

    Indian Academy of Sciences (India)

    Unknown

    Viscosities; oxalic acid and its salts; water + THF mixtures; structure-breakers. 1. Introduction ... has found its application in the organic syntheses as manifested from ... water. In other words, these results indicate that oxalic acid and its salts mix ...

  5. Nitrite reduction and methanogenesis in a single-stage UASB reactor.

    Science.gov (United States)

    Borges, L I; López-Vazquez, C M; García, H; van Lier, J B

    2015-01-01

    In this study, nitrite reduction and methanogenesis in a single-stage upflow anaerobic sludge blanket (UASB) reactor was investigated, using high-strength synthetic domestic wastewater as substrate. To assess long-term effects and evaluate the mechanisms that allow successful nitrite reduction and methanogenesis in a single-stage UASB, sludge was exposed to relatively high nitrite loading rates (315 ± 13 mgNO(2)(-)-N/(l.d)), using a chemical oxygen demand (COD) to nitrogen ratio of 18 gCOD/gNO(2)(-)-N, and an organic loading rate of 5.4 ± 0.2 gCOD/(l.d). In parallel, the effects of sludge morphology on methanogenesis inhibition were studied by performing short-term batch activity tests at different COD/NO(2)(-)-N ratios with anaerobic sludge samples. In long-term tests, denitrification was practically complete and COD removal efficiency did not change significantly after nitrite addition. Furthermore, methane production only decreased by 13%, agreeing with the reducing equivalents requirement for complete NO(2)(-) reduction to N₂. Apparently, the spatial separation of denitrification and methanogenesis zones inside the UASB reactor allowed nitrite reduction and methanogenesis to occur at the same moment. Batch tests showed that granules seem to protect methanogens from nitrite inhibition, probably due to transport limitations. Combined COD and N removal via nitrite in a single-stage UASB reactor could be a feasible technology to treat high-strength domestic wastewater.

  6. Carbon-Fiber Nitrite Microsensor for In Situ Biofilm Monitoring

    Science.gov (United States)

    During nitrification, nitrite is produced as an intermediate when ammonia is oxidized to nitrate. It is well established that nitrifying biofilm are involved in nitrification episodes in chloraminated drinking water distribution systems with nitrite accumulation occurring during ...

  7. On the mechanism of sulfite activation of chloroplast thylakoid ATPase and the relation of ADP tightly bound at a catalytic site to the binding change mechanism

    International Nuclear Information System (INIS)

    Du, Z.; Boyer, P.D.

    1990-01-01

    Washed chloroplast thylakoid membranes upon exposure to [ 3 H]ADP retain in tightly bound [ 3 H]ADP on a catalytic site of the ATP synthase. The presence of sufficient endogenous or added Mg 2+ results in an enzyme with essentially no ATPase activity. Sulfite activates the ATPase, and many molecules of ATP per synthase can be hydrolyzed before most of the bound [ 3 H]ADP is released, a result interpreted as indicating that the ADP is not bound at a site participating in catalysis by the sulfite-activated enzyme. The authors present evidence that this is not the case. The Mg 2+ - and ADP-inhibited enzyme when exposed to MgATP and 20-100 mM sulfite shows a lag of about 1 min at 22 degree C and of about 15 s at 37 degree C before reaching the same steady-state rate as attained with light-activated ATPase that has not been inhibited by Mg 2+ and ADP. The lag is not eliminated if the enzyme is exposed to sulfite prior to MgATP addition, indicating that ATPase turnover is necessary for the activation. The release of most of the bound [ 3 H]ADP parallels the onset of ATPase activity, although some [ 3 H]ADP is not released even with prolonged catalytic turnover and may be on poorly active or inactive enzyme or at noncatalytic sites. The results are consistent with most of the tightly bound [ 3 H]ADP being at a catalytic site and being replaced as this Mg 2+ - and ADP-inhibited site regains equivalent participation with other catalytic sites on the activated enzyme. The sulfite activation can be explained by sulfite combination at a P i binding site of the enzyme-ADP-Mg 2+ complex to give a form more readily activated by ATP binding at an alternative site

  8. Mechanism of anodic oxidation of molybdenum and tungsten in nitrate-nitrite melts

    International Nuclear Information System (INIS)

    Yurkinskij, V.P.; Firsova, E.G.; Morachevskij, A.G.

    1987-01-01

    The mechanism of anode oxidation of tungsten and molybdenum in NaNO 3 -KNO 3 (50 mass %) nitrate-nitrite melts with NaNO 2 -KNO 2 (0.5-50 mass %) addition and in NaNO 2 -KNO 2 (35 mole %) nitrite melt in the 516-580 K temperature range is studied. It is supposed that the process of anode dissloving of the mentioned metals in nitrite melt and nitrate-nitrite mixtures is two-electron. Formation of oxide passivating film is possible under electrolysis on the anode surface, the film is then dissolved in nitrate-nitrite melt with formation of molybdates or tungstates

  9. Effect of processing and cooking on total and soluble oxalate content in frozen root vegetables prepared for consumption

    Directory of Open Access Journals (Sweden)

    Z. LISIEWSKA

    2008-12-01

    Full Text Available The oxalate content of beetroot, carrot, celeriac and parsnip after freezing by traditional and modified methods (the latter resulting in a convenience food product, and after the preparation of frozen products for consumption was evaluated. The highest content of total and soluble oxalates (105 and 82 mg 100 g-1 fresh matter was found in beetroot. The lowest proportion (55% of soluble oxalates was noted in celeriac; this proportion was higher in the remaining vegetables, being broadly similar for each of them. Blanching brought about a significant decrease in total and soluble oxalates in fresh vegetables. Cooking resulted in a higher loss of oxalates. The level of oxalates in products prepared for consumption directly after freezing approximated that before freezing. Compared with the content before freezing, vegetables prepared for consumption by cooking after frozen storage contained less oxalates, except for total oxalates in parsnip and soluble oxalates in beetroot and celeriac. The highest ratio of oxalates to calcium was found in raw beetroot; it was two times lower in raw carrot; five times lower in raw celeriac; and eight times lower in raw parsnip. These ratios were lower after technological and culinary processing. The percentage of oxalate bound calcium depended on the species; this parameter was not significantly affected by the procedures applied. The true retention of oxalates according to Judprasong et al. (2006 was lower than retention calculated taking its content in 100 g fresh matter into account.;

  10. The effects of copper proximity on oxalate production in Fibroporia radiculosa

    Science.gov (United States)

    Katie M. Jenkins; Carol A. Clausen; Frederick Green III

    2014-01-01

    Copper remains a key component used in wood preservatives available today. However, the observed tolerance of several critical wood rotting organisms continues to be problematic. Tolerance to copper has been linked to the production and accumulation of oxalate, which precipitates copper into insoluble copper-oxalate crystals, thus inactivating copper ions. The purpose...

  11. Tetraphenylphosphonium hydrogen oxalate

    Directory of Open Access Journals (Sweden)

    Philip A. W. Dean

    2008-01-01

    Full Text Available In the title compound, C24H20P+·C2HO4−, two symmetry-independent ion pairs are present. The cations aggregate into puckered sheets via zigzag infinite chains of sixfold phenyl embraces and parallel fourfold phenyl embraces, while the anions form hydrogen-bonded chains between the sheets of cations. In the two independent oxalate anions, the angles between the normals to the two least-squares carboxylate COO planes are unusually large, viz. 72.5 (1 and 82.1 (1°.

  12. Nanoscale observations of the effect of citrate on calcium oxalate precipitation on calcite surfaces.

    Science.gov (United States)

    Burgos-Cara, Alejandro; Ruiz-Agudo, Encarnacion; Putnis, Christine V.

    2016-04-01

    Calcium oxalate (CaC2O4ṡxH2O) minerals are naturally occurring minerals found in fossils, plants, kidney stones and is a by-product in some processes such as paper, food and beverage production [1,2]. In particular, calcium oxalate monohydrate phase (COM) also known as whewellite (CaC2O4ṡH2O), is the most frequently reported mineral phase found in urinary and kidney stones together with phosphates. Organic additives are well known to play a key role in the formation of minerals in both biotic and abiotic systems, either facilitating their precipitation or hindering it. In this regard, recent studies have provided direct evidence demonstrating that citrate species could enhance dissolution of COM and inhibit their precipitation. [3,4] The present work aims at evauate the influence of pH, citrate and oxalic acid concentrations in calcium oxalate precipitation on calcite surfaces (Island Spar, Chihuahua, Mexico) through in-situ nanoscale observation using in situ atomic force microscopy (AFM, Multimode, Bruker) in flow-through experiments. Changes in calcium oxalate morphologies and precipitated phases were observed, as well as the inhibitory effect of citrate on calcium oxalate precipitation, which also lead to stabilization an the amorphous calcium oxalate phase. [1] K.D. Demadis, M. Öner, Inhibitory effects of "green"additives on the crystal growth of sparingly soluble salts, in: J.T. Pearlman (Ed.), Green Chemistry Research Trends, Nova Science Publishers Inc., New York, 2009, pp. 265-287. [2] M. Masár, M. Zuborová, D. Kaniansky, B. Stanislawski, Determination of oxalate in beer by zone electrophoresis on a chip with conductivity detection, J. Sep. Sci. 26 (2003) 647-652. [3] Chutipongtanate S, Chaiyarit S, Thongboonkerd V. Citrate, not phosphate, can dissolve calcium oxalate monohydrate crystals and detach these crystals from renal tubular cells. Eur J Pharmacol 2012;689:219-25. [4] Weaver ML, Qiu SR, Hoyer JR, Casey WH, Nancollas GH, De Yoreo JJ

  13. Adaptable coordination of U(IV) in the 2D-(4,4) uranium oxalate network: From 8 to 10 coordinations in the uranium (IV) oxalate hydrates

    International Nuclear Information System (INIS)

    Duvieubourg-Garela, L.; Vigier, N.; Abraham, F.; Grandjean, S.

    2008-01-01

    Crystals of uranium (IV) oxalate hydrates, U(C 2 O 4 ) 2 .6H 2 O (1) and U(C 2 O 4 ) 2 .2H 2 O (2), were obtained by hydrothermal methods using two different U(IV) precursors, U 3 O 8 oxide and nitric U(IV) solution in presence of hydrazine to avoid oxidation of U(IV) into uranyl ion. Growth of crystals of solvated monohydrated uranium (IV) oxalate, U(C 2 O 4 ) 2 .H 2 O.(dma) (3), dma=dimethylamine, was achieved by slow diffusion of U(IV) into a gel containing oxalate ions. The three structures are built on a bi-dimensional complex polymer of U(IV) atoms connected through bis-bidentate oxalate ions forming [U(C 2 O 4 )] 4 pseudo-squares. The flexibility of this supramolecular arrangement allows modifications of the coordination number of the U(IV) atom which, starting from 8 in 1 increases to 9 in 3 and, finally increases, to 10 in 2. The coordination polyhedron changes from a distorted cube, formed by eight oxygen atoms of four oxalate ions, in 1, to a mono-capped square anti-prism in 3 and, finally, to a di-capped square anti-prism in 2, resulting from rotation of the oxalate ions and addition of one and two water oxygen atoms in the coordination of U(IV). In 1, the space between the ∞ 2 [U(C 2 O 4 ) 2 ] planar layers is occupied by non-coordinated water molecules; in 2, the space between the staggered ∞ 2 [U(C 2 O 4 ) 2 .2H 2 O] layers is empty, finally in 3, the solvate molecules occupy the interlayer space between corrugated ∞ 2 [U(C 2 O 4 ) 2 .H 2 O] sheets. The thermal decomposition of U(C 2 O 4 ) 2 .6H 2 O under air and argon atmospheres gives U 3 O 8 and UO 2 , respectively. - Graphical abstract: The adaptable environment of U(IV) in U(IV) oxalates: from eight cubic coordination in U(C 2 O 4 ) 2 .6H 2 O (a) completed by water oxygens to nine in [U(C 2 O 4 ) 2 .H 2 O](C 2 NH 5 ) (b) and ten coordination in U(C 2 O 4 ) 2 .2H 2 O (c)

  14. Kinetics and efficiency of the hydrated electron-induced dehalogenation by the sulfite/UV process.

    Science.gov (United States)

    Li, Xuchun; Fang, Jingyun; Liu, Guifang; Zhang, Shujuan; Pan, Bingcai; Ma, Jun

    2014-10-01

    Hydrated electron (e(aq)(-)), which is listed among the most reactive reducing species, has great potential for removal and detoxification of recalcitrant contaminants. Here we provided quantitative insight into the availability and conversion of e(aq)(-) in a newly developed sulfite/UV process. Using monochloroacetic acid as a simple e(aq)(-)-probe, the e(aq)(-)-induced dehalogenation kinetics in synthetic and surface water was well predicted by the developed models. The models interpreted the complex roles of pH and S(IV), and also revealed the positive effects of UV intensity and temperature quantitatively. Impacts of humic acid, ferrous ion, carbonate/bicarbonate, and surface water matrix were also examined. Despite the retardation of dehalogenation by electron scavengers, the process was effective even in surface water. Efficiency of the process was discussed, and the optimization approaches were proposed. This study is believed to better understand the e(aq)(-)-induced dehalogenation by the sulfite/UV process in a quantitative manner, which is very important for its potential application in water treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. The production of (14C) oxalate during the metabolism of (14C) carbohydrates in isolated rat hepatocytes.

    Science.gov (United States)

    Rofe, A M; James, H M; Bais, R; Edwards, J B; Conyers, R A

    1980-04-01

    Oxalate (14C) was produced during the metabolism of (U-14C) carbohydrates in hepatocytes isolated from normal rats. At 10 mM, the order of oxalate production was fructose > glycerol > xylitol > sorbitol greater than or equal to glucose in the ratio 10 : 4 : 3 : 1 : 1. This difference between oxalate production from fructose and glucose was reflected in their rates of utilisation, glucose being poorly metabolised in hepatocytes from fasted rats. Fructose was rapidly metabolised, producing glucose, lactate and pyruvate as the major metabolites. Glycerol, xylitol and sorbitol were metabolised at half the rate of fructose, the major metabolites being glucose, lactate and glycerophosphate. The marked similarity in the pattern of intermediary metabolites produced by these polyols was not, however, reflected in the rates of oxalate production. Hepatic polyol metabolism resulted in high levels of cytosolic NADH, as indicated by elevated lactate : pyruvate and glycerophosphate : dihydroxyacetone phosphate ratios. The artificial electron acceptor, phenazine methosulphate (PMS) stimulated oxalate production from the polyols, particularly xylitol. In the presence of PMS, the order of oxalate production was fructose greater than or equal to xylitol > glycerol > sorbitol in the ratio 10 : 10 : 6 : 2. The production of glucose, lactate and pyruvate from the polyols was also stimulated by PMS, whereas the general metabolism of fructose, including oxalate production, was little affected. Oxalate (14C) was produced from (1-14C), (2-14C) and (6-14C) but not (3,4-14C) glucose in hepatocytes isolated from non-fasted, pyridoxine-deficient rats. Whilst this labelling pattern is consistent with oxalate being produced by a number of pathways, it is suggested that metabolism via hydroxypyruvate is a major route for oxalate production from various carbohydrates, with perhaps the exception of xylitol, which appears to have an alternative mechanism for oxalate production. The observation that

  16. Green Alternatives to Nitrates and Nitrites in Meat-based Products-A Review.

    Science.gov (United States)

    Gassara, Fatma; Kouassi, Anne Patricia; Brar, Satinder Kaur; Belkacemi, Khaled

    2016-10-02

    Several food additives are added in food for their preservation to maintain the freshness of food (antioxidants) or to slow down or stop the growth of microorganisms (preservative agents). Nitrites and nitrates are used as preservative agents in meat. Nitrites give a smoked taste, a pinkish color in the meat and protect the consumers against the risk of bacterial deterioration. Their addition is however very limited as, in high dose, it can have risks on human health and the environment. Nitrites may also combine with secondary or tertiary amines to form N-nitroso derivatives. Certain N-nitroso compounds have been shown to produce cancers in a wide range of laboratory animals. Thus, alternatives of nitrates and nitrites are the object of numerous research studies. Alternatives, such as the addition of vitamins, fruits, chemicals products, natural products containing nitrite or spices, which have similar properties of nitrites, are in evaluation. In fact, spices are considered to have several organoleptic and anti-microbial properties which would be interesting to study. Several spices and combinations of spices are being progressively evaluated. This review discusses the sources of nitrites and nitrates, their use as additives in food products, their physicochemical properties, their negatives effects and the use of alternatives of nitrites and nitrates in preserving meat products.

  17. Acute oxalate nephropathy due to ′Averrhoa bilimbi′ fruit juice ingestion

    Directory of Open Access Journals (Sweden)

    G Bakul

    2013-01-01

    Full Text Available Irumban puli (Averrhoa bilimbi is commonly used as a traditional remedy in the state of Kerala. Freshly made concentrated juice has a very high oxalic acid content and consumption carries a high risk of developing acute renal failure (ARF by deposition of calcium oxalate crystals in renal tubules. Acute oxalate nephropathy (AON due to secondary oxalosis after consumption of Irumban puli juice is uncommon. AON due to A. bilimbi has not been reported before. We present a series of ten patients from five hospitals in the State of Kerala who developed ARF after intake of I. puli fruit juice. Seven patients needed hemodialysis whereas the other three improved with conservative management.

  18. Nutrition and oxalate metabolism in cats

    NARCIS (Netherlands)

    Dijcker, J.C.

    2013-01-01

    Over the past 30 years, a progressive increase in calcium oxalate (CaOx) urolith prevalence is reported in cats and dogs diagnosed with urolithiasis. This increase in prevalence appears to have occurred since dietary modifications were introduced to address magnesium ammonium phosphate urolithiasis.

  19. Characterization of calcium oxalate biominerals in Pereskia species (Cactaceae).

    Science.gov (United States)

    Monje, Paula V; Baran, Enrique J

    2009-01-01

    Calcium oxalate druses were isolated from the stems and leaves of six Pereskioideae family members and investigated by infrared spectroscopy, showing that in all samples the biomineral was present in the form of whewellite, CaC2O4 x H2O. As Pereskia is thought to represent the "ancestral" condition of the leafless stem-succulent cacti, these results suggest that the biomineralization of calcium oxalate in Cactaceae represents a primitive characteristic of the group and also support a close genetic relationship between Pereskia and Opuntia.

  20. Crystal structure of dimethylammonium hydrogen oxalate hemi(oxalic acid

    Directory of Open Access Journals (Sweden)

    Waly Diallo

    2015-05-01

    Full Text Available Single crystals of the title salt, Me2NH2+·HC2O4−·0.5H2C2O4, were isolated as a side product from the reaction involving Me2NH, H2C2O4 and Sn(n-Bu3Cl in a 1:2 ratio in methanol or by the reaction of the (Me2NH22C2O4 salt and Sn(CH33Cl in a 2:1 ratio in ethanol. The asymmetric unit comprises a dimethylammonium cation (Me2NH2+, an hydrogenoxalate anion (HC2O4−, and half a molecule of oxalic acid (H2C2O4 situated about an inversion center. From a supramolecular point of view, the three components interact together via hydrogen bonding. The Me2NH2+ cations and the HC2O4− anions are in close proximity through bifurcated N—H...(O,O hydrogen bonds, while the HC2O4− anions are organized into infinite chains via O—H...O hydrogen bonds, propagating along the a-axis direction. In addition, the oxalic acid (H2C2O4 molecules play the role of connectors between these chains. Both the carbonyl and hydroxyl groups of each diacid are involved in four intermolecular interactions with two Me2NH2+ and two HC2O4− ions of four distinct polymeric chains, via two N—H...O and two O—H...O hydrogen bonds, respectively. The resulting molecular assembly can be viewed as a two-dimensional bilayer-like arrangement lying parallel to (010, and reinforced by a C—H...O hydrogen bond.

  1. Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid.

    Directory of Open Access Journals (Sweden)

    Ja Yeong Jang

    Full Text Available Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS. Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10% and oxalic acid-WP8 (ai 8%, were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate. These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease.

  2. Modelling nitrite dynamics and associated feedback processes in the Benguela oxygen minimum zone

    Science.gov (United States)

    Mashifane, T. B.; Vichi, M.; Waldron, H. N.; Machu, E.; Garçonc, V.

    2016-08-01

    Understanding nitrite dynamics in oxygen minimum zones (OMZs) is a challenge as it represents an intermediary nitrogen species with a short turnover time. Nitrite is also reduced to nitrogen in OMZs, preventing its accumulation. This creates difficulties in detecting nitrite with colorimetric methods as concentrations may occur below detection limits in some regions. Nitrite concentrations are key to understanding intermediate nitrogen processes and their implication for nitrogen loss in OMZs. A coupled physical-biogeochemical model is applied in the Benguela OMZ to study nitrite dynamics and its associated feedback processes. Simulated results show occurrence of primary and secondary nitrite maxima in the Benguela shelf waters. The primary nitrite maxima in the Benguela are attributed to nitrification and nitrate assimilation as they occur in association with the nitracline. Secondary nitrite maxima accumulate in the Angola-Benguela Front (ABF) OMZ and are attributed to denitrification. The secondary nitrite maxima are consumed by anaerobic ammonium oxidation (anammox) off Walvis Bay. Nitrite maxima are restricted to the shelf off Walvis Bay and advected offshore in the ABF region. Interchanges between the poleward South Atlantic Central Water (SACW) and the equatorward, well-aerated Eastern South Atlantic Central Water (ESACW) drive the seasonality of nitrogen processes in the Benguela. Subsequent nitrite reduction in the Benguela OMZ leads to nitrous oxide production, with high concentrations occurring in the ABF region as a result of nitrification and denitrification. Off Walvis Bay, nitrous oxide production is low since nitrite is consumed by anammox. Nitrous oxide production occurs in thermocline, intermediate and deeper water masses in the ABF region. High N fluxes in the Benguela are attributed to nitrification as compared to anammox and denitrification. Results from this study demonstrate the role of intermediate nitrogen species in nitrogen feedback

  3. Complexation of Am(III) by oxalate in NaClO4 media

    International Nuclear Information System (INIS)

    Choppin, G.R.; Chen, J.F.

    1995-01-01

    The complexation of Am(III) by oxalate has been investigated in solutions of NaClO 4 up to 9.0 M ionic strength at 25 degrees C. The dissociation constants of oxalic acid were determined by potentiometric titration, while the stability constants of the Am(III)-oxalate complexation were measured by the solvent extraction technique. A thermodynamic model was constructed to predict the apparent equilibrium constants at different ionic strengths by applying the Pitzer equation using parameters for the Na + -HOx - , Na + -Ox - , AmOx + -ClO 4 - , and Na + -Am(Ox) 2 - interactions obtained by fitting the data

  4. A new method for the analysis of soluble and insoluble oxalate in pulp and paper matrices

    CSIR Research Space (South Africa)

    Sithole, Bruce

    2013-11-01

    Full Text Available A novel method has been developed for determining soluble and insoluble forms of oxalate in pulp and paper samples by ion chromatography. Methanesulphonic acid is used to dissolve insoluble oxalate, and total oxalate is then determined by ion...

  5. Hafnium(IV) complexation with oxalate at variable temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Friend, Mitchell T.; Wall, Nathalie A. [Washington State Univ., Pullmanm, WA (United States). Dept. of Chemistry

    2017-08-01

    Appropriate management of fission products in the reprocessing of spent nuclear fuel (SNF) is crucial in developing advanced reprocessing schemes. The addition of aqueous phase complexing agents can prevent the co-extraction of these fission products. A solvent extraction technique was used to study the complexation of Hf(IV) - an analog to fission product Zr(IV) - with oxalate at 15, 25, and 35 C in 1 M HClO{sub 4} utilizing a {sup 175+181}Hf radiotracer. The mechanism of the solvent extraction system of 10{sup -5} M Hf(IV) in 1 M HClO{sub 4} to thenoyltrifluoroacetone (TTA) in toluene demonstrated a 4{sup th}-power dependence in both TTA and H{sup +}, with Hf(TTA){sub 4} the only extractable species. The equilibrium constant for the extraction of Hf(TTA){sub 4} was determined to be log K{sub ex}=7.67±0.07 (25±1 C, 1 M HClO{sub 4}). The addition of oxalate to the aqueous phase decreased the distribution ratio, indicating aqueous Hf(IV)-oxalate complex formation. Polynomial fits to the distribution data identified the formation of Hf(ox){sup 2+} and Hf(ox){sub 2(aq)} and their stability constants were measured at 15, 25, and 35 C in 1 M HClO{sub 4}. van't Hoff analysis was used to calculate Δ{sub r}G, Δ{sub r}H, and Δ{sub r}S for these species. Stability constants were observed to increase at higher temperature, an indication that Hf(IV)-oxalate complexation is endothermic and driven by entropy.

  6. Calcium extraction from brine water and seawater using oxalic acid

    Science.gov (United States)

    Natasha, Nadia Chrisayu; Lalasari, Latifa Hanum

    2017-01-01

    Calcium can be extracted not only from rocks but also from natural liquor such as seawater and brine water. In order to extract the calcium from seawater and brine water, oxalic acid was used in this research. Effect of variations of the volume of the oxalic acid at a constant concentration in seawater and brine water to produce calcium was investigated. The concentration of oxalic acid was 100 g/l and the variations of its volume were 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml. The used seawater and brine water were firstly evaporated from 100 ml into 50 ml and then the oxalic acid was added into them with mixing to produce the calcium precipitates. The precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The SEM analysis showed that the precipitates from brine water were consisted of only calcium compound while from seawater sodium one was also found along with calcium compound. The XRD analysis showed that the calcium was present in the form of calcium oxalate for both seawater and brine water. The ICP-OES analysis of the filtrate from seawater precipitation showed that the its calcium content was decreased from 826.20 ppm to 0.04 ppm while from brine water, it decreased from 170.06 ppm to 1.96 ppm. These results showed that both seawater and brine water have the potential to be a raw material for calcium production.

  7. Crystal forms of the hydrogen oxalate salt of o-desmethylvenlafaxine.

    Science.gov (United States)

    Dichiarante, Elena; Curzi, Marco; Giaffreda, Stefano L; Grepioni, Fabrizia; Maini, Lucia; Braga, Dario

    2015-06-01

    To prepare new crystalline forms of the antidepressant o-desmethylvenlafaxine salt as potential new commercial forms and evaluate their physicochemical properties, in particular the dissolution rate. A new hydrogen oxalate salt of o-desmethylvenlafaxine hydrogen oxalate (ODV-OX) was synthesized, and a polymorph screening was performed using different solvents and crystallization conditions. Crystalline forms were characterized by a combination of solid-state techniques: X-ray powder diffraction, differential scanning calorimetry, thermogravimetric analysis, FT-IR spectroscopy and single crystal X-ray diffraction. The stability of all crystalline phases was tested under International Conference on Harmonisation (ICH) conditions (40°C and 75% Relative Humidity (RH)) for 1 week. Dissolution tests were performed on the hydrogen oxalate salt ODV-OX Form 1 and compared with dissolution test on the commercial form of the succinate salt of o-desmethylvenlafaxine. Five crystalline forms of ODV-OX were isolated, namely three hydrated forms (Form 1, Form 2, Form 3) and two anhydrous forms (Form 4 and Form 5). Comparative solubility tests on ODV-OX Form 1 and o-desmethylvenlafaxine succinate evidenced a significant increase in solubility for the hydrogen oxalate salt (142 g/l) with respect to the succinate salt (70 g/l). © 2015 Royal Pharmaceutical Society.

  8. Behaviour of Pu-IV with various ion exchangers in solutions containing nitric acid and oxalates

    International Nuclear Information System (INIS)

    Walter, E.; Ali, S.A.

    1982-02-01

    The distribution of Pu-IV on the ion exchangers Dowex 50W-X8, Dowex 1-X8 und Dowex Chelating Resin Al-X8 in the presence of various concentrations of nitric acid and oxalate were investigated. The results indicate that nitric acid and oxalic acid influence each other during complexation of Pu-IV with oxalate ions solutions containing nitric acid it is not possible to neglect the formation of Pu-IV nitrate complexes. The complex Pu(IV) (C 2 O 4 ) 3 2 - only is formed in solutions containing low nitric acid and high oxalic acid concentrations. The separation of Pu-IV in Dowex Chelating Resin from nitric acid solution in the presence of higher oxalate concentrations is possible, provided that the nitric acid concentration is lower than 0.25 molar [fr

  9. Effect of oxalic acid on the optical, thermal, dielectric and mechanical behaviour of ADP crystals

    International Nuclear Information System (INIS)

    Rajesh, P.; Ramasamy, P.

    2009-01-01

    The effect of the addition, over a concentration range from 1 to 5 mol%, of oxalic acid on the growth rate, optical transparency, hardness, dielectric behaviour, and SHG efficiency of ammonium dihydrogen phosphate single crystals grown by slow evaporation method has been investigated. UV-Vis studies show that the transparency of the oxalic acid added crystals decreased gradually. Thermal studies indicate that the decomposition temperatures of the crystal are decreased in oxalic acid added ADP crystals. It is observed from the dielectric measurements that the dielectric constant and dielectric loss increase with increase in temperature for all the crystals. Vicker's microhardness study reveals that the addition of higher concentration of oxalic acid decreases the hardness of the crystal. SHG efficiency of 1 mol% of oxalic acid is higher than the pure ADP.

  10. Two New Families of Lanthanide Mixed-Ligand Complexes, Oxalate-Carbonate and Oxalate-Formate: Synthesis and Structure of [Ce(H 2O)] 2(C 2O 4) 2(CO 3)·2.5 H 2O and Ce(C 2O 4)(HCO 2)

    Science.gov (United States)

    Romero, S.; Mosset, A.; Trombe, J. C.

    1996-12-01

    Two new families of lanthanide complexes associating the ligands oxalate and carbonate or oxalate and formate have been prepared under autogenous pressure at 200°C using a pseudo-hydrothermal method. The two families have been extended to some lanthanides ( Ln): oxalate-carbonate Ln= Ce, Pr, Nd, and Eu; oxalate-formate Ln= La, Ce, and Sm. The starting suspension contains either oxalate or a mixture of oxalate and oxalic acid. The structures have been solved for the element cerium. In both cases, the structure is built up from cerium atoms sharing all their oxygen atoms with oxalate and carbonate or oxalate and formate ligands, thus forming a three-dimensional network. The cerium polyhedra share either faces or edges or corners. The coordination scheme of the oxalate ligands is variable: bischelating, bischelating and monodentate, or bischelating and bismonodentate. The carbonate group acts as a bischelating and bismonodentate ligand while the formate group is chelating and monodentate. The characterization of these two original families by infrared spectra and thermal behavior is presented for some pure phases. A tentative explanation of the synthesis of these two phases will be emphasized.

  11. Low nitrous oxide production in intermittent-feed high performance nitritating reactors

    DEFF Research Database (Denmark)

    Su, Qingxian; Jensen, Malene M.; Smets, Barth F.

    Nitrous oxide (N2O) production from autotrophic nitrogen removal processes, especially nitritating systems, is of growing concern. N2O dynamics were characterized and N2O production factors were quantified in two lab-scale intermittent-feed nitritating SBRs. 93 ± 14% of the oxidized ammonium...... was converted to nitrite, with the average total net N2O production of 2.1 ± 0.7% of the ammonium oxidized. Operation with intermittent feeding appears an effective optimization approach to mitigate N2O emissions from nitritating systems. Net N2O production rates transiently increased with a rise in pH after...

  12. Characterization of wheat germin (oxalate oxidase) expressed by Pichia pastoris

    International Nuclear Information System (INIS)

    Pan, Heng-Yen; Whittaker, Mei M.; Bouveret, Romaric; Berna, Anne; Bernier, Francois; Whittaker, James W.

    2007-01-01

    High-level secretory expression of wheat (Triticum aestivum) germin/oxalate oxidase was achieved in Pichia pastoris fermentation cultures as an α-mating factor signal peptide fusion, based on the native wheat cDNA coding sequence. The oxalate oxidase activity of the recombinant enzyme is substantially increased (7-fold) by treatment with sodium periodate, followed by ascorbate reduction. Using these methods, approximately 1 g (4 x 10 4 U) of purified, activated enzyme was obtained following eight days of induction of a high density Pichia fermentation culture, demonstrating suitability for large-scale production of oxalate oxidase for biotechnological applications. Characterization of the recombinant protein shows that it is glycosylated, with N-linked glycan attached at Asn47. For potential biomedical applications, a nonglycosylated (S49A) variant was also prepared which retains essentially full enzyme activity, but exhibits altered protein-protein interactions

  13. EFFECTIVENESS OF USING DILUTE OXALIC ACID TO DISSOLVE HIGH LEVEL WASTE IRON BASED SLUDGE SIMULANT

    International Nuclear Information System (INIS)

    Ketusky, E

    2008-01-01

    At the Savannah River Site (SRS), near Aiken South Carolina, there is a crucial need to remove residual quantities of highly radioactive iron-based sludge from large select underground storage tanks (e.g., 19,000 liters of sludge per tank), in order to support tank closure. The use of oxalic acid is planned to dissolve the residual sludge, hence, helping in the removal. Based on rigorous testing, primarily using 4 and 8 wt% oxalic acid solutions, it was concluded that the more concentrated the acid, the greater the amount of residual sludge that would be dissolved; hence, a baseline technology on using 8 wt% oxalic acid was developed. In stark contrast to the baseline technology, reports from other industries suggest that the dissolution will most effectively occur at 1 wt% oxalic acid (i.e., maintaining the pH near 2). The driver for using less oxalic acid is that less (i.e., moles) would decrease the severity of the downstream impacts (i.e., required oxalate solids removal efforts). To determine the initial feasibility of using 1 wt% acid to dissolve > 90% of the sludge solids, about 19,000 liters of representative sludge was modeled using about 530,000 liters of 0 to 8 wt% oxalic acid solutions. With the chemical thermodynamic equilibrium based software results showing that 1 wt% oxalic acid could theoretically work, simulant dissolution testing was initiated. For the dissolution testing, existing simulant was obtained, and an approximate 20 liter test rig was built. Multiple batch dissolutions of both wet and air-dried simulant were performed. Overall, the testing showed that dilute oxalic acid dissolved a greater fraction of the stimulant and resulted in a significantly larger acid effectiveness (i.e., grams of sludge dissolved/mole of acid) than the baseline technology. With the potential effectiveness confirmed via simulant testing, additional testing, including radioactive sludge testing, is planned

  14. NITRITE AND NITRATE DETERMINATIONS IN PLASMA - A CRITICAL-EVALUATION

    NARCIS (Netherlands)

    MOSHAGE, H; KOK, B; HUIZENGA, [No Value; JANSEN, PLM

    Plasma nitrite and nitrate determinations are increasingly being used in clinical chemistry as markers for the activity of nitric oxide synthase and the production of nitric oxide radicals. However, a systematic evaluation of the determination of nitrite and nitrate in plasma has not been performed.

  15. Nitrite and nitrate determinations in plasma: a critical evaluation

    NARCIS (Netherlands)

    Moshage, H.; Kok, B.; Huizenga, J. R.; Jansen, P. L.

    1995-01-01

    Plasma nitrite and nitrate determinations are increasingly being used in clinical chemistry as markers for the activity of nitric oxide synthase and the production of nitric oxide radicals. However, a systematic evaluation of the determination of nitrite and nitrate in plasma has not been performed.

  16. Intercomparison of the measurements of oxalic acid in aerosols by gas chromatography and ion chromatography

    Science.gov (United States)

    Kawamura, Kimitaka; Barrie, Leonard A.; Toom-Sauntry, Desiree

    2010-12-01

    Oxalate, the anion of oxalic acid, is one of the most abundant measurable organic species in atmospheric aerosols. Traditionally, this bifunctional species has been measured by gas chromatography (GC) after derivatization to butyl ester and by ion chromatography (IC) without derivatization. However, there are few published comparisons of the two techniques. Here, we report the results of an intercomparison study for the measurement of oxalic acid in Arctic aerosols (oxalic acid by GC ranged from 6.5-59.1 ng m -3 (av. 26.0 ng m -3, median 26.2 ng m -3) whereas those by IC ranged from 6.6-52.1 ng m -3 (av. 26.6 ng m -3, median 25.4 ng m -3). They showed a good correlation ( r = 0.84) with a slope of 0.96. Thus, observations of oxalate obtained by GC employing dibutyl esters are almost equal to those by IC. Because the accuracy of oxalic acid by GC method largely depends on the method used, it is important to strictly examine the recovery in each study.

  17. Role of blood and vascular smooth muscle in the vasoactivity of nitrite

    Science.gov (United States)

    Liu, Taiming; Schroeder, Hobe J.; Barcelo, Lisa; Bragg, Shannon L.; Terry, Michael H.; Wilson, Sean M.; Power, Gordon G.

    2014-01-01

    Recent evidence from humans and rats indicates that nitrite is a vasodilator under hypoxic conditions by reacting with metal-containing proteins to produce nitric oxide (NO). We tested the hypothesis that near-physiological concentrations of nitrite would produce vasodilation in a hypoxia- and concentration-dependent manner in the hind limb of sheep. Anesthetized sheep were instrumented to measure arterial blood pressure and femoral blood flows continuously in both hind limbs. Nitrite was infused into one femoral artery to raise the nitrite concentration in the femoral vein by 10 to 15-fold while the sheep breathed 50%, 14% or 12% oxygen in inspired air. In contrast to reports in humans and rats, the nitrite infusion had no measurable effect on mean femoral blood flows or vascular conductances, regardless of inspired O2 levels. In vitro experiments showed no significant difference in the release of NO from nitrite in sheep and human red blood cells. Further experiments demonstrated nitrite is converted to NO in rat artery homogenates faster than sheep arteries, and that this source of NO production is attenuated in the presence of a heme oxidizer. Finally, western blots indicate that concentrations of the heme-containing protein cytoglobin, but not myoglobin, are markedly lower in sheep arteries compared with rats. Overall, the results demonstrate that nitrite is not a physiological vasodilator in sheep. This is likely due to a lack of conversion of nitrite to NO within the vascular smooth muscle, perhaps due to deficient amounts of the heme-containing protein cytoglobin. PMID:25108012

  18. Effect of sodium nitrite on toxin production by Clostridium botulinum in bacon.

    Science.gov (United States)

    Christiansen, L N; Tompkin, R B; Shaparis, A B; Kueper, T V; Johnston, R W; Kautter, D A; Kolari, O J

    1974-04-01

    Pork bellies were formulated to 0, 30, 60, 120, 170, or 340 mug of nitrite per g of meat and inoculated with Clostridium botulinum via pickle or after processing and slicing. Processed bacon was stored at 7 or 27 C and assayed for nitrite, nitrate, and botulinal toxin at different intervals. Nitrite levels declined during processing and storage. The rate of decrease was more rapid at 27 than at 7 C. Although not added to the system, nitrate was detected in samples during processing and storage at 7 and 27 C. The amount of nitrate found was related to formulated nitrite levels. No toxin was found in samples incubated at 7 C throughout the 84-day test period. At 27 C, via pickle, inoculated samples with low inoculum (210 C. botulinum per g before processing and 52 per g after processing) became toxic if formulated with 120 mug of nitrite per g of meat or less. Toxin was not detected in bacon formulated with 170 or 340 mug of nitrite per g of meat under these same conditions. Toxin was detected at all formulated nitrite levels in bacon inoculated via the pickle with 19,000 C. botulinum per g (4,300 per g after processing) and in samples inoculated after slicing. However, increased levels of formulated nitrite decreased the probability of botulinal toxin formation in bacon inoculated by both methods.

  19. Evidence of a natural marine source of oxalic acid and a possible link to glyoxal

    Science.gov (United States)

    Rinaldi, Matteo; Decesari, Stefano; Carbone, Claudio; Finessi, Emanuela; Fuzzi, Sandro; Ceburnis, Darius; O'Dowd, Colin D.; Sciare, Jean; Burrows, John P.; Vrekoussis, Mihalis; Ervens, Barbara; Tsigaridis, Kostas; Facchini, Maria Cristina

    2011-08-01

    This paper presents results supporting the existence of a natural source of oxalic acid over the oceans. Oxalate was detected in "clean-sector" marine aerosol samples at Mace Head (Ireland) (53°20'N, 9°54'W) during 2006, and at Amsterdam Island (37°48'S, 77°34'E) from 2003 to 2007, in concentrations ranging from 2.7 to 39 ng m-3 and from 0.31 to 17 ng m-3, respectively. The oxalate concentration showed a clear seasonal trend at both sites, with maxima in spring-summer and minima in fall-winter, being consistent with other marine biogenic aerosol components (e.g., methanesulfonic acid, non-sea-salt sulfate, and aliphatic amines). The observed oxalate was distributed along the whole aerosol size spectrum, with both a submicrometer and a supermicrometer mode, unlike the dominant submicrometer mode encountered in many polluted environments. Given its mass size distribution, the results suggest that over remote oceanic regions oxalate is produced through a combination of different formation processes. It is proposed that the cloud-mediated oxidation of gaseous glyoxal, recently detected over remote oceanic regions, may be an important source of submicrometer oxalate in the marine boundary layer. Supporting this hypothesis, satellite-retrieved glyoxal column concentrations over the two sampling sites exhibited the same seasonal concentration trend of oxalate. Furthermore, chemical box model simulations showed that the observed submicrometer oxalate concentrations were consistent with the in-cloud oxidation of typical marine air glyoxal mixing ratios, as retrieved by satellite measurements, at both sites.

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

    Science.gov (United States)

    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 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 complex Al 2(OH) 2(C 2O 4) 44- to exist in a

  1. NITRITE REDUCTASE ACTIVITY OF NON-SYMBIOTIC HEMOGLOBINS FROM ARABIDOPSIS THALIANA†

    Science.gov (United States)

    Tiso, Mauro; Tejero, Jesús; Kenney, Claire; Frizzell, Sheila; Gladwin, Mark T.

    2013-01-01

    Plant non-symbiotic hemoglobins possess hexa-coordinate heme geometry similar to the heme protein neuroglobin. We recently discovered that deoxygenated neuroglobin converts nitrite to nitric oxide (NO), an important signaling molecule involved in many processes in plants. We sought to determine whether Arabidopsis thaliana non-symbiotic hemoglobins class 1 and 2 (AHb1 and AHb2) might function as nitrite reductases. We found that the reaction of nitrite with deoxygenated AHb1 and AHb2 generates NO gas and iron-nitrosyl-hemoglobin species. The bimolecular rate constants for nitrite reduction to NO are 19.8 ± 3.2 and 4.9 ± 0.2 M−1s−1, at pH = 7.4 and 25°C, respectively. We determined the pH dependence of these bimolecular rate constants and found a linear correlation with the concentration of protons, indicating the requirement for one proton in the reaction. Release of free NO gas during reaction in anoxic and hypoxic (2% oxygen) conditions was confirmed by chemiluminescence detection. These results demonstrate that deoxygenated AHb1 and AHb2 reduce nitrite to form NO via a mechanism analogous to that observed for hemoglobin, myoglobin and neuroglobin. Our findings suggest that during severe hypoxia and in the anaerobic plant roots, especially in water submerged species, non-symbiotic hemoglobins provide a viable pathway for NO generation via nitrite reduction. PMID:22620259

  2. Nitrite as a stimulus for ammonia-starved Nitrosomonas europaea

    NARCIS (Netherlands)

    Laanbroek, H.J.; Bär-Gilissen, M.J.; Hoogveld, H.L.

    2002-01-01

    Ammonia-starved cells of Nitrosomonas europaea are able to preserve a high level of ammonia-oxidizing activity in the absence of ammonium. However, when the nitrite-oxidizing cells that form part of the natural nitrifying community do not keep pace with the ammonia-oxidizing cells, nitrite

  3. Uranyl oxalate hydrates: structures and IR spectra

    International Nuclear Information System (INIS)

    Giesting, P.A.; Porter, N.J.; Burns, P.C.

    2006-01-01

    The novel compound (UO 2 ) 2 C 2 O 4 (OH) 2 (H 2 O) 2 (UrOx2A) and the previously studied compound UO 2 C 2 O 4 (H 2 O) 3 (UrOx3) have been synthesized by mild hydrothermal methods. Single crystal diffraction data collected at 125 K using MoK α radiation and a CCD-based area detector were used to solve and refine the crystal structures by full-matrix least-squares techniques to agreement indices (UrOx2A, UrOx3) wR 2 = 0.037, 0.049 for all data, and R1 0.015, 0.024 calculated for 1285, 2194 unique reflections respectively. The compound UrOx2A is triclinic, space group P1, Z = 1, a = 5.5353(4), b 6.0866(4), c = 7.7686(6) Aa, α = 85.6410(10) , β = 89.7740(10) , γ = 82.5090(10) , V = 258.74(3) Aa 3 . The compound UrOx3 is monoclinic, space group P2 1 /c, Z = 4, a = 5.5921(4), b = 16.9931(13), c = 9.3594(7) Aa, β = 99.5330(10) , V = 877.11(11) Aa 3 . The structures consist of chains of uranyl pentagonal bipyramids connected by oxalate groups and, in UrOx2A, hydroxyl groups; UrOx2A is also notable for its high (2:1) ratio of uranyl to oxalate groups, higher than any observed in other published structures of uranyl oxalates. The structure determined for UrOx3, previously studied by Jayadevan and Chackraburtty (1972); Mikhailov et al. (1999) is in agreement with the previous results; however, the increased precision of the present low-temperature structure refinement allows for the assignment of H atom positions based on the difference Fourier map of electron density. The infrared spectra of these two materials collected at room temperature are also presented and compared with previous work on uranyl oxalate systems. (orig.)

  4. Role of nitrite in the photochemical formation of radicals in the snow.

    Science.gov (United States)

    Jacobi, Hans-Werner; Kleffmann, Jörg; Villena, Guillermo; Wiesen, Peter; King, Martin; France, James; Anastasio, Cort; Staebler, Ralf

    2014-01-01

    Photochemical reactions in snow can have an important impact on the composition of the atmosphere over snow-covered areas as well as on the composition of the snow itself. One of the major photochemical processes is the photolysis of nitrate leading to the formation of volatile nitrogen compounds. We report nitrite concentrations determined together with nitrate and hydrogen peroxide in surface snow collected at the coastal site of Barrow, Alaska. The results demonstrate that nitrite likely plays a significant role as a precursor for reactive hydroxyl radicals as well as volatile nitrogen oxides in the snow. Pollution events leading to high concentrations of nitrous acid in the atmosphere contributed to an observed increase in nitrite in the surface snow layer during nighttime. Observed daytime nitrite concentrations are much higher than values predicted from steady-state concentrations based on photolysis of nitrate and nitrite indicating that we do not fully understand the production of nitrite and nitrous acid in snow. The discrepancy between observed and expected nitrite concentrations is probably due to a combination of factors, including an incomplete understanding of the reactive environment and chemical processes in snow, and a lack of consideration of the vertical structure of snow.

  5. an oxalate-peroxide complex used in the preparation of doped barium titanate

    NARCIS (Netherlands)

    van der Gijp, S.; Winnubst, Aloysius J.A.; Verweij, H.

    1998-01-01

    A method is described for the preparation of homogeneously doped barium titanate, which can be applied in non-linear dielectric elements. Ba and Ti salts are dissolved, mixed with hydrogen peroxide and added to a solution of ammonium oxalate, resulting in the formation of an insoluble peroxo-oxalate

  6. Characterization of metabolic network of oxalic acid biosynthesis through RNA seq data analysis of developing spikes of finger millet (Eleusine coracana): Deciphering the role of key genes involved in oxalate formation in relation to grain calcium accumulation.

    Science.gov (United States)

    Akbar, Naved; Gupta, Supriya; Tiwari, Apoorv; Singh, K P; Kumar, Anil

    2018-04-05

    In the present study, we identified seven major genes of oxalic acid biosynthesis pathway (SGAT, GGAT, ICL, GLO, MHAR, APO and OXO) from developing spike transcriptome of finger millet using rice as a reference. Sequence alignment of identified genes showed high similarity with their respective homolog in rice except for OXO and GLO. Transcript abundance (FPKM) reflects the higher accumulation of identified genes in GP-1 (low calcium genotype) as compared to GP-45 (high calcium genotype) which was further confirmed by qRT-PCR analysis, indicating differential oxalate formation in both genotypes. Determination of oxalic acid and tartaric acid content in developing spikes explain that higher oxalic acid content in GP-1 however, tartaric acid content was more in GP-45. Higher calcium content in GP-45 and lower oxalate accumulation may be due to the diversion of more ascorbic acid into tartaric acid and may correspond to less formation of calcium oxalate. Our results suggest that more than one pathway for oxalic acid biosynthesis might be present in finger millet with probable predominance of ascorbate-tartarate pathway rather than glyoxalate-oxalate conversion. Thus, finger millet can be use as an excellent model system for understanding more specific role of nutrients-antinutrients interactions, as evident from the present study. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Effect of different brewing times on soluble oxalate content of loose-packed black teas and tea bags.

    Science.gov (United States)

    Mahdavi, Reza; Lotfi Yagin, Neda; Liebman, Michael; Nikniaz, Zeinab

    2013-02-01

    Because of the postulated role of increased dietary oxalate intake in calcium oxalate stone formation, the effect of different brewing times on soluble oxalate contents of loose-packed black tea and tea bags was studied. The oxalate content of 25 different samples of loose-packed black teas after brewing at 5, 10, 15, 30, and 60 min and of ten brands of tea bags after infusion for 1, 2, 3, 4, and 5 min was measured by enzymatic assay. The oxalate concentration resulting from different brewing times ranged from 4.3 to 6.2 mg/240 ml for loose-packed black teas and from 2.7 to 4.8 mg/240 ml for tea bags. There was a stepwise increase in oxalate concentration associated with increased brewing times.

  8. Facile fabrication of cobalt oxalate nanostructures with superior specific capacitance and super-long cycling stability

    Science.gov (United States)

    Cheng, Guanhua; Si, Conghui; Zhang, Jie; Wang, Ying; Yang, Wanfeng; Dong, Chaoqun; Zhang, Zhonghua

    2016-04-01

    Transition metal oxalate materials have shown huge competitive advantages for applications in supercapacitors. Herein, nanostructured cobalt oxalate supported on cobalt foils has been facilely fabricated by anodization, and could directly serve as additive/binder-free electrodes for supercapacitors. The as-prepared cobalt oxalate electrodes present superior specific capacitance of 1269 F g-1 at the current density of 6 A g-1 in the galvanostatic charge/discharge test. Moreover, the retained capacitance is as high as 87.2% as the current density increases from 6 A g-1 to 30 A g-1. More importantly, the specific capacitance of cobalt oxalate retains 91.9% even after super-long cycling of 100,000 cycles. In addition, an asymmetric supercapacitor assembled with cobalt oxalate (positive electrode) and activated carbon (negative electrode) demonstrates excellent capacitive performance with high energy density and power density.

  9. Nitrite spray treatment to promote red color stability of vacuum packaged beef.

    Science.gov (United States)

    Song, Xiao; Cornforth, Daren; Whittier, Dick; Luo, Xin

    2015-01-01

    Sodium nitrite solutions were sprayed on select grade boneless rib (M. longissimus thoracis) and bottom round (mainly M. biceps femoris) steaks individually, to form bright red nitric oxide myoglobin (NO-Mb) in vacuum packages. Our objective was to determine the optimum level of nitrite in spray for stable raw steak redness, low or no residual nitrite, and low surface pinking (ham-like cured color) after cooking. Results showed that steaks sprayed with 100-350 ppm nitrite solutions had 3.0-3.6g weight gain and a calculated level of 1.3-5.3mg nitrite added/kg steak, but very low (color during 21 days of storage at 1°C (a*>10; chroma C*>16). Raw steak redness was less stable in round than rib. Visual scores for pinkness after cooking were low, indicating that cooked color at even the highest nitrite treatment (350 ppm) was acceptable. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Radiation preservation with reduced nitrites of bacon and other cured meats - a review

    International Nuclear Information System (INIS)

    Singh, H.

    1987-01-01

    The main problem caused by nitrite as a preservative is the formation of carcinogenic nitrosamines in bacon and other cured meats. This has led to a search for alternatives to the use of nitrite. Irradiation with reduced level of nitrite is a promising alternative to the use of current levels of nitrite. Radurization (radiation pasteurization) of bacon containing 20 to to 40 mg/kg of nitrite in evacuated packages, irradiated and stored at 4 degrees C, gives a product with good organoleptic qualities and extended shelf life of > 80 days vs. < days 30 days for the conventionally treated bacon. Radappertization (radiation sterilization) of bacon containing 20 mg/kg of nitrite at a dose of about 30 kGy, irradiated at -20 degrees or lower in evacuated packages, results in a product that is shelf stable for months to years at room temperature (∼ 25 degrees C). It has organoleptic properties comparable to commercial bacon in terms of color, flavor, odor and texture. Irradiation also reduces the nitrite and preformed nitrosamines present in bacon. Lower levels of nitrosamines are formed on cooking irradiated bacon containing presently used commercial levels of nitrite (120-150 mg/kg) and the levels of nitrosamines become negligible with 20 mg/kg of nitrite. Various aspects of preservation of bacon and other cured meats are reviewed in this report with emphasis on radiation processing. 357 refs

  11. Food sources of nitrates and nitrites: the physiologic context for potential health benefits.

    Science.gov (United States)

    Hord, Norman G; Tang, Yaoping; Bryan, Nathan S

    2009-07-01

    The presence of nitrates and nitrites in food is associated with an increased risk of gastrointestinal cancer and, in infants, methemoglobinemia. Despite the physiologic roles for nitrate and nitrite in vascular and immune function, consideration of food sources of nitrates and nitrites as healthful dietary components has received little attention. Approximately 80% of dietary nitrates are derived from vegetable consumption; sources of nitrites include vegetables, fruit, and processed meats. Nitrites are produced endogenously through the oxidation of nitric oxide and through a reduction of nitrate by commensal bacteria in the mouth and gastrointestinal tract. As such, the dietary provision of nitrates and nitrites from vegetables and fruit may contribute to the blood pressure-lowering effects of the Dietary Approaches to Stop Hypertension (DASH) diet. We quantified nitrate and nitrite concentrations by HPLC in a convenience sample of foods. Incorporating these values into 2 hypothetical dietary patterns that emphasize high-nitrate or low-nitrate vegetable and fruit choices based on the DASH diet, we found that nitrate concentrations in these 2 patterns vary from 174 to 1222 mg. The hypothetical high-nitrate DASH diet pattern exceeds the World Health Organization's Acceptable Daily Intake for nitrate by 550% for a 60-kg adult. These data call into question the rationale for recommendations to limit nitrate and nitrite consumption from plant foods; a comprehensive reevaluation of the health effects of food sources of nitrates and nitrites is appropriate. The strength of the evidence linking the consumption of nitrate- and nitrite-containing plant foods to beneficial health effects supports the consideration of these compounds as nutrients.

  12. Crosstalk between nitrite, myoglobin and reactive oxygen species to regulate vasodilation under hypoxia.

    Directory of Open Access Journals (Sweden)

    Matthias Totzeck

    Full Text Available The systemic response to decreasing oxygen levels is hypoxic vasodilation. While this mechanism has been known for more than a century, the underlying cellular events have remained incompletely understood. Nitrite signaling is critically involved in vessel relaxation under hypoxia. This can be attributed to the presence of myoglobin in the vessel wall together with other potential nitrite reductases, which generate nitric oxide, one of the most potent vasodilatory signaling molecules. Questions remain relating to the precise concentration of nitrite and the exact dose-response relations between nitrite and myoglobin under hypoxia. It is furthermore unclear whether regulatory mechanisms exist which balance this interaction. Nitrite tissue levels were similar across all species investigated. We then investigated the exact fractional myoglobin desaturation in an ex vivo approach when gassing with 1% oxygen. Within a short time frame myoglobin desaturated to 58±12%. Given that myoglobin significantly contributes to nitrite reduction under hypoxia, dose-response experiments using physiological to pharmacological nitrite concentrations were conducted. Along all concentrations, abrogation of myoglobin in mice impaired vasodilation. As reactive oxygen species may counteract the vasodilatory response, we used superoxide dismutase and its mimic tempol as well as catalase and ebselen to reduce the levels of reactive oxygen species during hypoxic vasodilation. Incubation of tempol in conjunction with catalase alone and catalase/ebselen increased the vasodilatory response to nitrite. Our study shows that modest hypoxia leads to a significant nitrite-dependent vessel relaxation. This requires the presence of vascular myoglobin for both physiological and pharmacological nitrite levels. Reactive oxygen species, in turn, modulate this vasodilation response.

  13. Investigation of composition and properties of some neptunium (5) oxalate compounds

    International Nuclear Information System (INIS)

    Zubarev, V.G.; Krot, N.N.

    1981-01-01

    A simple way of neptunium (5) oxalate synthesis is described and its composition is determined: (NpO 2 ) 2 C 2 O 4 xH 2 O. The compound is precipitated from solution during pouring together stoichiometric quantities of neptunium (5) nitrate and ammonium, sodium or potassium oxalate at pH=4-5. An explanation to unusual effect of solubility change with time of neptunium (5) monooxalate complexes and alkali metal or ammonium ion is found taking into account the slow formation of precipitate and low solubility of the compound obtained (0.62 g/l as to metal). Thermal decomposition of the compound is studied. At 180 deg C a water molecule is split off and at 260 deg C decomposition of neptunium oxalate starts. IR spectra and interplane distances (dsub(hkl)) of the compound crystal lattice are determined. New data on the synthesis and properties of complex neptunium (5) oxalates and monovalent cation in second sphere with the ratio ligand: metal=2:1 and 3:1 are presented. On the basis of results of IR spectroscopy and X-ray phase analyses a supposition is made on the existence of such complex compounds [ru

  14. Study on the Key Technology of High Purity Strontium Titanate Powder Synthesized from Oxalic Acid Co-sediment Precipitation

    Science.gov (United States)

    Bi, Xiaoguo; Dong, Yingnan; Li, Yingjie; Niu, Wei; Tang, Jian; Ding, Shuang; Li, Meiyang

    2017-09-01

    Oxalate coprecipitation is applied in this paper, high purity titanium tetrachloride, and after the purification of strontium chloride, match with a certain concentration of solution, oxalate and strontium chloride and titanium tetrachloride in 1.005:1.000 make strontium titanium mixture ratio, slowly under 60°C to join in oxalic acid solution, aging around 4 h, get oxygen titanium strontium oxalate (SrTiO(C2O4)2 • 4H2 ) precipitation, after washing, drying and other process made oxygen titanium strontium oxalate powder.

  15. Behaviors of nitrite in cured meat

    International Nuclear Information System (INIS)

    Miwa, Misao

    1980-01-01

    The behaviors of nitrite in cured meat were studied by means of 15 N on the basis of the gaseous 15 N volume from the added nitric acid. The myoglobin, 15 N-nitrite and ascorbate model systems showed a 15 N recovery rate of approximately 100%, but actual meat samples, treated similarly, showed a recovery rate ranging from 66 to 90%, with formation of an unidentified 15 N agent. The largest amount of this unidentified agent was obtained by reaction of the 0.05 M NaCl-soluble dialyzable fraction of meat with 15 N-nitrite. When the reaction product was isolated by Sephadex column chromatography, 15 N in the fraction, which was thought to be the agent, contained approximately 26% of the added 15 N, possessed no UV absorption, and was negative for a ninhydrin reagent. Of the NaCl soluble fraction, reaction in the acidic fraction produced the largest quantity of the unidentified 15 N compound (31% of the added 15 N). This compound was strongly acidic and consisted of 30.7% C, 6.6% H and 4.9% N on element analysis. It showed no mutagenicity against Salmonella by Ames Test. (Chiba, N.)

  16. Hydrothermal synthesis of two layered indium oxalates with 12-membered apertures

    International Nuclear Information System (INIS)

    Chen Zhenxia; Zhou Yaming; Weng Linhong; Zhang Haoyu; Zhao Dongyuan

    2003-01-01

    Two layered indium oxalates, In(C 2 O 4 ) 2.5 (C 3 N 2 H 12 )(H 2 O) 3 , I, and In(C 2 O 4 ) 1.5 (H 2 O) 3 , II, have been hydrothermally synthesized. In I, the linkage between indium and oxalate units gives rise to a sheet with a rectangular 12-membered aperture (six indium atoms and six oxalate units). Indium atom of II has an unusual pentagonal bipyramidal coordination arrangement. The connectivity between indium and oxalate units forms a neutral puckered layer with 12- (along a-axis) and eight-membered (along b-axis) apertures. Crystal data for these two indium oxalates are as follows: I, triclinic, space group: P-1 (No. 2), a=8.725(3) A, b=9.170(3) A, c=9.901(3) A, α=98.101(4) deg. , β=97.068(4) deg. , γ=102.403(4) deg. , V=756.3(4) A 3 , Z=2, M=463.0(5), ρ calc =2.042 g/cm 3 , R 1 =0.0377, wR 2 =0.0834. II, monoclinic, space group: P2 1 /c (No. 14), a=10.203(5) A, b=6.638(1) A, c=11.152(7) A, β=95.649(4) deg. , V=751.7(4)A 3 , Z=4, M=300.9(0), ρ calc =2.659 g/cm 3 , R 1 =0.0229, wR 2 =0.0488. TG analyses indicate the water molecules of I can be removed at 150 deg. C. The dehydrated product retains structural integrity

  17. On the mechanism of sulfite activation of chloroplast thylakoid ATPase and the relation of ADP tightly bound at a catalytic site to the binding change mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Du, Z.; Boyer, P.D. (Univ. of California, Los Angeles (USA))

    1990-01-16

    Washed chloroplast thylakoid membranes upon exposure to ({sup 3}H)ADP retain in tightly bound ({sup 3}H)ADP on a catalytic site of the ATP synthase. The presence of sufficient endogenous or added Mg{sup 2+} results in an enzyme with essentially no ATPase activity. Sulfite activates the ATPase, and many molecules of ATP per synthase can be hydrolyzed before most of the bound ({sup 3}H)ADP is released, a result interpreted as indicating that the ADP is not bound at a site participating in catalysis by the sulfite-activated enzyme. The authors present evidence that this is not the case. The Mg{sup 2+}- and ADP-inhibited enzyme when exposed to MgATP and 20-100 mM sulfite shows a lag of about 1 min at 22{degree}C and of about 15 s at 37{degree}C before reaching the same steady-state rate as attained with light-activated ATPase that has not been inhibited by Mg{sup 2+} and ADP. The lag is not eliminated if the enzyme is exposed to sulfite prior to MgATP addition, indicating that ATPase turnover is necessary for the activation. The release of most of the bound ({sup 3}H)ADP parallels the onset of ATPase activity, although some ({sup 3}H)ADP is not released even with prolonged catalytic turnover and may be on poorly active or inactive enzyme or at noncatalytic sites. The results are consistent with most of the tightly bound ({sup 3}H)ADP being at a catalytic site and being replaced as this Mg{sup 2+}- and ADP-inhibited site regains equivalent participation with other catalytic sites on the activated enzyme. The sulfite activation can be explained by sulfite combination at a P{sub i} binding site of the enzyme-ADP-Mg{sup 2+} complex to give a form more readily activated by ATP binding at an alternative site.

  18. Structures and reaction pathways of the molybdenum centres of sulfite-oxidizing enzymes by pulsed EPR spectroscopy.

    Science.gov (United States)

    Enemark, John H; Astashkin, Andrei V; Raitsimring, Arnold M

    2008-12-01

    SOEs (sulfite-oxidizing enzymes) are physiologically vital and occur in all forms of life. During the catalytic cycle, the five-co-ordinate square pyramidal oxo-molybdenum active site passes through the Mo(V) state, and intimate details of the structure can be obtained from variable frequency pulsed EPR spectroscopy through the hyperfine and nuclear quadrupole interactions of nearby magnetic nuclei. By employing variable spectrometer operational frequencies, it is possible to optimize the measurement conditions for difficult quadrupolar nuclei of interest (e.g. (17)O, (33)S, (35)Cl and (37)Cl) and to simplify the interpretation of the spectra. Isotopically labelled model Mo(V) compounds provide further insight into the electronic and geometric structures and chemical reactions of the enzymes. Recently, blocked forms of SOEs having co-ordinated sulfate, the reaction product, were detected using (33)S (I=3/2) labelling. This blocking of product release is a possible contributor to fatal human sulfite oxidase deficiency in young children.

  19. The use and control of nitrate and nitrite for the processing of meat products.

    Science.gov (United States)

    Honikel, Karl-Otto

    2008-01-01

    Nitrate and nitrite are used for the purpose of curing meat products. In most countries the use of both substances, usually added as potassium or sodium salts, is limited. Either the ingoing or the residual amounts are regulated by laws. The effective substance is nitrite acting primarily as an inhibitor for some microorganisms. Nitrite added to a batter of meat is partially oxidized to nitrate by sequestering oxygen - thus it acts as an antioxidant - a part of nitrite is bound to myoglobin, forming the heat stable NO-myoglobin, a part is bound to proteins or other substances in meat. Nitrate may be reduced to nitrite in raw meat products by microorganisms. As oxidation and reduction may occur the concentrations of nitrite plus nitrate in a product has to be controlled and measured especially if the residual amounts are regulated. This sum of both compounds is important for the human body. Intake of nitrate with food leads to its absorption over the digestive tract into the blood. In the oral cavity nitrate appears again where it is reduced to nitrite. With the saliva the nitrite is mixed with food, having the same effect as nitrite in a batter (inhibiting growth of some pathogenic microorganisms) and swallowed. In the stomach nitrite can eventually form carcinogenic nitrosamines in the acidic environment.

  20. Nitrite and nitrate concentrations and metabolism in breast milk, infant formula, and parenteral nutrition.

    Science.gov (United States)

    Jones, Jesica A; Ninnis, Janet R; Hopper, Andrew O; Ibrahim, Yomna; Merritt, T Allen; Wan, Kim-Wah; Power, Gordon G; Blood, Arlin B

    2014-09-01

    Dietary nitrate and nitrite are sources of gastric NO, which modulates blood flow, mucus production, and microbial flora. However, the intake and importance of these anions in infants is largely unknown. Nitrate and nitrite levels were measured in breast milk of mothers of preterm and term infants, infant formulas, and parenteral nutrition. Nitrite metabolism in breast milk was measured after freeze-thawing, at different temperatures, varying oxygen tensions, and after inhibition of potential nitrite-metabolizing enzymes. Nitrite concentrations averaged 0.07 ± 0.01 μM in milk of mothers of preterm infants, less than that of term infants (0.13 ± 0.02 μM) (P milk. Concentrations in parenteral nutrition were equivalent to or lower than those of breast milk. Freeze-thawing decreased nitrite concentration ~64%, falling with a half-life of 32 minutes at 37°C. The disappearance of nitrite was oxygen-dependent and prevented by ferricyanide and 3 inhibitors of lactoperoxidase. Nitrite concentrations in breast milk decrease with storage and freeze-thawing, a decline likely mediated by lactoperoxidase. Compared to adults, infants ingest relatively little nitrite and nitrate, which may be of importance in the modulation of blood flow and the bacterial flora of the infant GI tract, especially given the protective effects of swallowed nitrite. © 2013 American Society for Parenteral and Enteral Nutrition.

  1. Music stimuli lead to increased levels of nitrite in unstimulated mixed saliva.

    Science.gov (United States)

    Jin, Luyuan; Zhang, Mengbi; Xu, Junji; Xia, Dengsheng; Zhang, Chunmei; Wang, Jingsong; Wang, Songlin

    2018-06-15

    Concentration of salivary nitrate is approximately 10-fold to that of serum. Many circumstances such as acute stress could promote salivary nitrate secretion and nitrite formation. However, whether other conditions can also be used as regulators of salivary nitrate/nitrite has not yet been explored. The present study was designed to determine the influence of exposure to different music on the salivary flow rate and nitrate secretion and nitrite formation. Twenty-four undergraduate students (12 females and 12 males) were exposed to silence, rock music, classical music or white noise respectively on four consecutive mornings. The unstimulated salivary flow rate and stimulated salivary flow rate were measured. Salivary ionic (Na + , Ca 2+ Cl - , and PO 4 3- ) content and nitrate/nitrite levels were detected. The unstimulated salivary flow rate was significantly increased after classical music exposure compared to that after silence. Salivary nitrite levels were significantly higher upon classical music and white noise stimulation than those under silence in females. However, males were more sensitive only to white noise with regard to the nitrite increase. In conclusion, this study demonstrated that classical music stimulation promotes salivary nitrite formation and an increase in saliva volume was observed. These observations may play an important role in regulating oral function.

  2. Optimization of free ammonia concentration for nitrite accumulation in shortcut biological nitrogen removal process.

    Science.gov (United States)

    Chung, Jinwook; Shim, Hojae; Park, Seong-Jun; Kim, Seung-Jin; Bae, Wookeun

    2006-03-01

    A shortcut biological nitrogen removal (SBNR) utilizes the concept of a direct conversion of ammonium to nitrite and then to nitrogen gas. A successful SBNR requires accumulation of nitrite in the system and inhibition of the activity of nitrite oxidizers. A high concentration of free ammonia (FA) inhibits nitrite oxidizers, but unfortunately decreases the ammonium removal rate as well. Therefore, the optimal range of FA concentration is necessary not only to stabilize nitrite accumulation but also to achieve maximum ammonium removal. In order to derive such optimal FA concentrations, the specific substrate utilization rates of ammonium and nitrite oxidizers were measured. The optimal FA concentration range appeared to be 5-10 mg/L for the adapted sludge. The simulated results from the modified inhibition model expressed by FA and ammonium/nitrite concentrations were shown very similar to the experimental results.

  3. ROLE OF THE MICROFLORA IN DISTAL INTESTINAL TRACT BY MAINTAINING OXALATE HOMEOSTASIS

    Directory of Open Access Journals (Sweden)

    Osolodchenko T.P.

    2015-05-01

    Full Text Available Human intestinal microflora is part of the human body and performs numerous function. Considerable research interest is in the field of probiotics for the prevention of kidney stones, which is one of the most common urological diseases.Urolithiasis is one of the most common urological diseases. This is polyetiological disease congenital and acquired character with complex physical and chemical processes that occur not only in the urinary system, but also the whole body. None of the treatments does not guarantee full recovery of the patient and often leads to relapse. The open methods of removal stones yield news minimally invasive the technologys. Development of stone formation depends on the presence of many factors, metabolic disorders, chronic urinary tract infections, genetic disorders and more. Most have the following metabolic disorders as hypercalciuria, hiperurikuria, hipotsytraturia , hyperoxaluria and hipomahniuria. Among all types of urolithiasis kaltsiyoksalatnyy ranked first in the prevalence rate - about 75.0 - 85.0 % of cases. Dietary restriction by oxalates іs the unreliable method of preventing disease. Although there is evidence for the growth inhibition normobiocenosis representatives, which in turn enhances the absorption of salts of oxalic acid oxalate in the application of sodium , magnesium and cobalt in their intragastric administration. Recently published many papers on the impact on the level of oxalate intestinal microflora. The first publications appeared on the influence of gram-negative obligate anaerobes O. formigenes the concentration of oxalate in the urine. This anaerobic bacteria living in the colon, its prevalence - 46.0 % - 77.0 % of the adult population. O. formigenes reveals the symbiotic interaction with the human body by reducing absorption of oxalate in the intestinal cavity with subsequent decrease in their concentration in plasma and urine. O. formigenes has two key enzymes - oksalyl

  4. Quantifying the sources and sinks of nitrite in the oxygen minimum zone of the Eastern Tropical South Pacific

    Science.gov (United States)

    Ji, Qixing; Widner, Brittany; Jayakumar, Amal; Ward, Bess; Mulholland, Margaret

    2017-04-01

    In coastal upwelling regions, high surface productivity leads to high export and intense remineralization consuming oxygen. This, in combination with slow ventilation, creates oxygen minimum zones (OMZ) in eastern boundary regions of the ocean, such as the one off the Peruvian coast in the Eastern Tropical South Pacific. The OMZ is characterized by a layer of high nitrite concentration coinciding with water column anoxia. Sharp oxygen gradients are located above and below the anoxic layer (upper and lower oxyclines). Thus, the OMZ harbors diverse microbial metabolisms, several of which involve the production and consumption of nitrite. The sources of nitrite are ammonium oxidation and nitrate reduction. The sinks of nitrite include anaerobic ammonium oxidation (anammox), canonical denitrification and nitrite oxidation to nitrate. To quantify the sources and sinks of nitrite in the Peruvian OMZ, incubation experiments with 15N-labeled substrates (ammonium, nitrite and nitrate) were conducted on a research cruise in January 2015. The direct measurements of instantaneous nitrite production and consumption rates were compared with ambient nitrite concentrations to evaluate the turnover rate of nitrite in the OMZ. The distribution of nitrite in the water column showed a two-peak structure. A primary nitrite maximum (up to 0.5 μM) was located in the upper oxycline. A secondary nitrite maximum (up to 10 μM) was found in the anoxic layer. A nitrite concentration minimum occurred at the oxic-anoxic interface just below the upper oxycline. For the sources of nitrite, highest rates of ammonium oxidation and nitrate reduction were detected in the upper oxycline, where both nitrite and oxygen concentrations were low. Lower rates of nitrite production were detected within the layer of secondary nitrite maximum. For the sinks of nitrite, the rates of anammox, denitrification and nitrite oxidation were the highest just below the oxic-anoxic interface. Low nitrite consumption

  5. Nitrite Biosensing via Selective Enzymes—A Long but Promising Route

    Directory of Open Access Journals (Sweden)

    M. Gabriela Almeida

    2010-12-01

    Full Text Available The last decades have witnessed a steady increase of the social and political awareness for the need of monitoring and controlling environmental and industrial processes. In the case of nitrite ion, due to its potential toxicity for human health, the European Union has recently implemented a number of rules to restrict its level in drinking waters and food products. Although several analytical protocols have been proposed for nitrite quantification, none of them enable a reliable and quick analysis of complex samples. An alternative approach relies on the construction of biosensing devices using stable enzymes, with both high activity and specificity for nitrite. In this paper we review the current state-of-the-art in the field of electrochemical and optical biosensors using nitrite reducing enzymes as biorecognition elements and discuss the opportunities and challenges in this emerging market.

  6. Liquid waste processing from plutonium (III) oxalate precipitation

    International Nuclear Information System (INIS)

    Esteban, A.; Cassaniti, P.; Orosco, E.H.

    1990-01-01

    Plutonium (III) oxalate filtrates contain about 0.2M oxalic acid, 0.09M ascorbic acid, 0.05M hydrazine, 1M nitric acid and 20-100 mg/l of plutonium. The developed treatment of liquid wastes consist in two main steps: a) Distillation to reduce up to 10% of the initial volume and refluxing to destroy organic material. Then, the treated solution is suitable to adjust the plutonium at the tetravalent state by addition of hydrogen peroxide and the nitric molarity up to 8.6M. b) Recovery and purification of plutonium by anion exchange using two columns in series containing Dowex 1-X4 resin. With the proposed process, it is possible to transform 38 litres of filtrates with 40mg/l of Pu into 0.1 l of purified solution with 15-20g/l of Pu. This solution is suitable to be recycled in the Pu (III) oxalate precipitation process. This process has several potential advantages over similar liquid waste treatments. These include: 1) It does not increase the liquid volume. 2) It consumes only few reagents. 3) The operations involved are simple, requiring limited handling and they are feasible to automatization. 4) The Pu recovery factor is about 99%. (Author) [es

  7. Investigation on clean-up of Zr and HDBP in PUREX process with UDMH oxalate

    International Nuclear Information System (INIS)

    Zhang Youzhi; Wang Xuanjun; Li Zhengli; Liu Xiangxuan

    2007-01-01

    It is generally accepted that the interracial crud formation is related to the complex formation of Zr with degradation products of TBP, such as DBP and MBP, in PUREX process, especially in the first cycle. The crud seriously deteriorates the operation of extraction column and therefore must be properly cleared up. Various clear up methods were studied and those with salt-free washing agents were recently focused. In this paper a new scrubbing agent 1,1- dimethylhydrazine (UDMH) oxalate was proposed, the optimized experimental conditions were described, and the possible mechanism was discussed. The influence of different factors, including reaction temperature, UDMH oxalate concentration, organic-to-aqueous phase ratio, and free UDMH concentration, on the decontamination factors were examined with simulated Zr- and/or DBP-loaded solvents. The optical experimental parameters are found as follows: temperature 40-60 degree C, phase ratio V (o) /V (a) =1, concentration of UDMH oxalate solution 0.4-0.6 mol/L. Especialy some UDMH was added into the UDMH oxalate queues solution to make the concentration of free UDMH 0.2-0.3 mol/L. Under these conditions, the decontaminator factor of Zr from the corresponding simulated solvent with UDMH oxalate is up to 143, slightly higher than that with sodium carbonate. The decontamination factor of HDBP from the corresponding simulated solvent with UDMH oxalate is up to 100, similar to sodium carbonate. (authors)

  8. Sulfite induced autoxidation of Cu(II/tetra/ penta and hexaglycine complexes: spectrophotometric and rotating-ring-disk glassy carbon electrode studies and analytical potentialities

    Directory of Open Access Journals (Sweden)

    Alipázaga Maria V.

    2003-01-01

    Full Text Available The oxidation of Cu(II complexes with tetra, penta and hexaglycine in borate buffer aqueous solution, by dissolved oxygen is strongly accelerated by sulfite. The formation of Cu(III complexes with maximum absorbances at 250 nm (e = 9000 mol-1 L cm-1 and 365 nm (e = 7120 mol-1 L cm-1 was also characterized by using rotating ring-disk voltammetry, whose anodic and cathodic components were observed in voltammograms recorded in solutions containing Cu(II. Voltammograms, obtained at various rotation speeds, showed that the Cu(III species electrochemically generated is not stable over the entire time window of the experiment and in solutions containing tetraglycine the overall limiting current is controlled by the kinetics of an equilibrium involving Cu(II species.The calculated first order rate constant of the decomposition was 4.37x10-3 s-1. Electrochemical experiments carried out in Cu(II solutions after the addition of relatively small amounts of sulfite demonstrated that the Cu(III species formed in the chemical reaction is the same as the one collected at the ring electrode when Cu(II is oxidized at the disk electrode in ring-disk voltammetry. The concentration of Cu(III complexes is proportional to the amount of added sulfite and the results indicated that indirect analytical methods for sulfite may be developed by means of spectrophotometric or amperometric detection of the chemically generated product.

  9. Thiosulfate and Sulfite Distributions in Porewater of Marine-Sediments Related to Manganese, Iron, and Sulfur Geochemistry

    DEFF Research Database (Denmark)

    Thamdrup, B; Finster, Kai; Fossing, Henrik

    1994-01-01

    Depth distributions of thiosulfate (S2O32-) and sulfite (SO32-) were measured in the porewaters of a Danish salt marsh and subtidal marine sediments by HPLC analysis after derivatization with DTNP [2,2'-dithiobis(5-nitropyridine)]. The distributions were compared to the redox zonation as indicate...

  10. Role of nitrite, urate and pepsin in the gastroprotective effects of saliva

    Science.gov (United States)

    Rocha, Bárbara S.; Lundberg, Jon O; Radi, Rafael; Laranjinha, João

    2016-01-01

    Dietary nitrate is now recognized as an alternative substrate for nitric oxide (•NO) production in the gut. This novel pathway implies the sequential reduction of nitrate to nitrite, •NO and other bioactive nitrogen oxides but the physiological relevance of these oxidants has remained elusive. We have previously shown that dietary nitrite fuels an hitherto unrecognized nitrating pathway at acidic gastric pH, through which pepsinogen is nitrated in the gastric mucosa, yielding a less active form of pepsin in vitro. Here, we demonstrate that pepsin is nitrated in vivo and explore the functional impact of protein nitration by means of peptic ulcer development. Upon administration of pentagastrin and human nitrite-rich saliva or sodium nitrite to rats, nitrated pepsin was detected in the animal's stomach by immunoprecipitation. •NO was measured in the gastric headspace before and after nitrite instillation by chemiluminescence. At the end of each procedure, the stomach's lesions, ranging from gastric erosions to haemorrhagic ulcers, were scored. Nitrite increased gastric •NO by 200-fold (pstomach, preventing the progression of gastric ulcers. PMID:27156250

  11. Primary Nonfunction of Renal Allograft Secondary to Acute Oxalate Nephropathy

    Directory of Open Access Journals (Sweden)

    Ravi Parasuraman

    2011-01-01

    Full Text Available Primary nonfunction (PNF accounts for 0.6 to 8% of renal allograft failure, and the focus on causes of PNF has changed from rejection to other causes. Calcium oxalate (CaOx deposition is common in early allograft biopsies, and it contributes in moderate intensity to higher incidence of acute tubular necrosis and poor graft survival. A-49-year old male with ESRD secondary to polycystic kidney disease underwent extended criteria donor kidney transplantation. Posttransplant, patient developed delayed graft function (DGF, and the biopsy showed moderately intense CaOx deposition that persisted on subsequent biopsies for 16 weeks, eventually resulting in PNF. The serum oxalate level was 3 times more than normal at 85 μmol/L (normal <27 μmol/L. Allograft nephrectomy showed massive aggregates of CaOx crystal deposition in renal collecting system. In conclusion, acute oxalate nephropathy should be considered in the differential diagnosis of DGF since optimal management could change the outcome of the allograft.

  12. Improving the two-step remediation process for CCA-treated wood. Part I, Evaluating oxalic acid extraction

    Science.gov (United States)

    Carol Clausen

    2004-01-01

    In this study, three possible improvements to a remediation process for chromated-copper-arsenate (CCA) treated wood were evaluated. The process involves two steps: oxalic acid extraction of wood fiber followed by bacterial culture with Bacillus licheniformis CC01. The three potential improvements to the oxalic acid extraction step were (1) reusing oxalic acid for...

  13. The Relationship between Serum Oxalic Acid, Central Hemodynamic Parameters and Colonization by Oxalobacter formigenes in Hemodialysis Patients.

    Science.gov (United States)

    Gulhan, Baris; Turkmen, Kultigin; Aydin, Merve; Gunay, Murat; Cıkman, Aytekin; Kara, Murat

    2015-06-01

    Elevated pulse wave velocity (PWV) and central aortic blood pressures are independent predictors of increased cardiovascular morbidity and mortality in hemodialysis (HD) patients. Oxalic acid is a uremic retention molecule that is extensively studied in the pathogenesis of calcium oxalate stones. Oxalobacter formigenes, a member of the colon microbiota, has important roles in oxalate homeostasis. Data regarding the colonization by and the exact role of O. formigenes in the pathogenesis of oxalic acid metabolism in HD patients are scant. Hence, we aimed to determine the relationship between fecal O. formigenes colonization, serum oxalic acid and hemodynamic parameters in HD patients with regard to the colo-reno-cardiac axis. Fifty HD patients were enrolled in this study. PWV and central aortic systolic (cASBP) and diastolic blood pressures (cADBP) were measured with a Mobil-O-Graph (I.E.M. GmbH, Stolberg, Germany). Serum oxalic acid levels were assessed by ELISA, and fecal O. formigenes DNA levels were isolated and measured by real-time PCR. Isolation of fecal O. formigenes was found in only 2 HD patients. One of them had 113,609 copies/ml, the other one had 1,056 copies/ml. Serum oxalic acid levels were found to be positively correlated with PWV (r = 0.29, p = 0.03), cASBP (r = 0.33, p = 0.001) and cADBP (r = 0.42, p = 0.002) and negatively correlated with LDL (r = -0.30, p = 0.03). In multivariate linear regression analysis, PWV was independently predicted by oxalic acid, glucose and triglyceride. This is the first study that demonstrates the absence of O. formigenes as well as a relation between serum oxalic acid and cASBP, cADBP and PWV in HD patients. Replacement of O. formigenes with pre- and probiotics might decrease serum oxalic acid levels and improve cardiovascular outcomes in HD patients.

  14. Tetrakis(acetonitrilecopper(I hydrogen oxalate–oxalic acid–acetonitrile (1/0.5/0.5

    Directory of Open Access Journals (Sweden)

    A. Timothy Royappa

    2013-10-01

    Full Text Available In the title compound, [Cu(CH3CN4](C2HO4·0.5C2H2O4·0.5CH3CN, the CuI ion is coordinated by the N atoms of four acetonitrile ligands in a slightly distorted tetrahedral environment. The oxalic acid molecule lies across an inversion center. The acetonitrile solvent molecule is disordered across an inversion center and was refined with half occupancy. In the crystal, the hydrogen oxalate anions and oxalic acid molecules are linked via O—H...O hydrogen bonds, forming chains along [010].

  15. Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate ...

    African Journals Online (AJOL)

    Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate on the ... The test plant was sown in aluminium-polluted soil (conc. ... The perseverance of the test plant in the aluminium spiked soil is an indication of adaptation to the stress ...

  16. Ingested nitrate and nitrite and stomach cancer risk: an updated review.

    Science.gov (United States)

    Bryan, Nathan S; Alexander, Dominik D; Coughlin, James R; Milkowski, Andrew L; Boffetta, Paolo

    2012-10-01

    Nitrite and nitrate are naturally occurring molecules in vegetables and also added to cured and processed meats to delay spoilage and pathogenic bacteria growth. Research over the past 15 years has led to a paradigm change in our ideas about health effects of both nitrite and nitrate. Whereas, historically nitrite and nitrate were considered harmful food additives and listed as probable human carcinogens under conditions where endogenous nitrosation could take place, they are now considered by some as indispensible nutrients essential for cardiovascular health by promoting nitric oxide (NO) production. We provide an update to the literature and knowledge base concerning their safety. Most nitrite and nitrate exposure comes from naturally occurring and endogenous sources and part of the cell signaling effects of NO involve nitrosation. Nitrosation must now be considered broadly in terms of both S- and N-nitrosated species, since S-nitrosation is kinetically favored. Protein S-nitrosation is a significant part of the role of NO in cellular signal transduction and is involved in critical aspects of cardiovascular health. A critical review of the animal toxicology literature of nitrite indicates that in the absence of co-administration of a carcinogenic nitrosamine precursor, there is no evidence for carcinogenesis. Newly published prospective epidemiological cohort studies indicate that there is no association between estimated intake of nitrite and nitrate in the diet and stomach cancer. This new and growing body of evidence calls for a reconsideration of nitrite and nitrate safety. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Nitrite reductase activity and inhibition of H₂S biogenesis by human cystathionine ß-synthase.

    Directory of Open Access Journals (Sweden)

    Carmen Gherasim

    Full Text Available Nitrite was recognized as a potent vasodilator >130 years and has more recently emerged as an endogenous signaling molecule and modulator of gene expression. Understanding the molecular mechanisms that regulate nitrite metabolism is essential for its use as a potential diagnostic marker as well as therapeutic agent for cardiovascular diseases. In this study, we have identified human cystathionine ß-synthase (CBS as a new player in nitrite reduction with implications for the nitrite-dependent control of H₂S production. This novel activity of CBS exploits the catalytic property of its unusual heme cofactor to reduce nitrite and generate NO. Evidence for the possible physiological relevance of this reaction is provided by the formation of ferrous-nitrosyl (Fe(II-NO CBS in the presence of NADPH, the human diflavin methionine synthase reductase (MSR and nitrite. Formation of Fe(II-NO CBS via its nitrite reductase activity inhibits CBS, providing an avenue for regulating biogenesis of H₂S and cysteine, the limiting reagent for synthesis of glutathione, a major antioxidant. Our results also suggest a possible role for CBS in intracellular NO biogenesis particularly under hypoxic conditions. The participation of a regulatory heme cofactor in CBS in nitrite reduction is unexpected and expands the repertoire of proteins that can liberate NO from the intracellular nitrite pool. Our results reveal a potential molecular mechanism for cross-talk between nitrite, NO and H₂S biology.

  18. Amperometric Carbon Fiber Nitrite Microsensor for In Situ Biofilm Monitoring

    Science.gov (United States)

    A highly selective needle type solid state amperometric nitrite microsensor based on direct nitrite oxidation on carbon fiber was developed using a simplified fabrication method. The microsensor’s tip diameter was approximately 7 µm, providing a high spatial resolution of at lea...

  19. Overexpression of the Maize Sulfite Oxidase Increases Sulfate and GSH Levels and Enhances Drought Tolerance in Transgenic Tobacco

    Directory of Open Access Journals (Sweden)

    Zongliang Xia

    2018-03-01

    Full Text Available Sulfite oxidase (SO plays a pivotal role in sulfite metabolism. In our previous study, sulfite-oxidizing function of the SO from Zea mays (ZmSO was characterized. To date, the knowledge of ZmSO’s involvement in abiotic stress response is scarce. In this study, we aimed to investigate the role of ZmSO in drought stress. The transcript levels of ZmSO were relatively high in leaves and immature embryos of maize plants, and were up-regulated markedly by PEG-induced water stress. Overexpression of ZmSO improved drought tolerance in tobacco. ZmSO-overexpressing transgenic plants showed higher sulfate and glutathione (GSH levels but lower hydrogen peroxide (H2O2 and malondialdehyde (MDA contents under drought stress, indicating that ZmSO confers drought tolerance by enhancing GSH-dependent antioxidant system that scavenged ROS and reduced membrane injury. In addition, the transgenic plants exhibited more increased stomatal response than the wild-type (WT to water deficit. Interestingly, application of exogenous GSH effectively alleviated growth inhibition in both WT and transgenic plants under drought conditions. qPCR analysis revealed that the expression of several sulfur metabolism-related genes was significantly elevated in the ZmSO-overexpressing lines. Taken together, these results imply that ZmSO confers enhanced drought tolerance in transgenic tobacco plants possibly through affecting stomatal regulation, GSH-dependent antioxidant system, and sulfur metabolism-related gene expression. ZmSO could be exploited for developing drought-tolerant maize varieties in molecular breeding.

  20. The crystal structure of paramagnetic copper(ii) oxalate (CuC2O4):

    DEFF Research Database (Denmark)

    Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel

    2014-01-01

    Synthetic copper(ii) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(ii) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have...... the composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(ii) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar....... The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns...

  1. Oxalate content of different drinkable dilutions of tea infusions after different brewing times.

    Science.gov (United States)

    Lotfi Yagin, Neda; Mahdavi, Reza; Nikniaz, Zeinab

    2012-01-01

    The aims of this study were to determine the effect of different brewing times and diluting on oxalate content of loose-packed black teas consumed in Tabriz, Iran. The oxalate content of black teas after brewing for 5, 10, 15, 30, 60 minutes was measured in triplicate by enzymatic assay. In order to attain the most acceptable dilution of tea infusions, tea samples which were brewed for 15, 30 and 60 minutes were diluted two (120 ml), three (80 ml) and four (60 ml) times respectively. There was a stepwise increase in oxalate concentrations associated with increased brewing times (Pbrewing times, respectively. There were significant differences between the mean oxalate content of different dilutions after brewing for 15, 30 and 60 minutes (Pbrewing times and different dilution was below the recommended levels. Therefore, it seems that consumption of black tea several times per day would not pose significant health risk in kidney stone patients and susceptible individuals.

  2. Preliminary nitrite, nitrate and colour analysis of Malaysian edible bird’s nest

    Directory of Open Access Journals (Sweden)

    Meei Chien Quek

    2015-05-01

    Full Text Available The high nitrite content in edible bird’s nests is a major concern to the local swiftlet industry. It lowers the price of the edible bird’s nests and it brings severe health hazards to consumers and farmers. This research investigated the nitrite and nitrate contents of eight types of local edible bird’s nests by using ion chromatography system and evaluating its colour using the CIE system in L∗a∗b∗ parameters. The nitrite content obtained ranged from 5.7 μg/g for the house nests to 843.8 μg/g for the cave nests. The nitrate content for the house and cave nests was 98.2 μg/g and 36,999.4 μg/g, respectively. The cave nests with darker and redder colour had higher nitrite and nitrate contents than the brighter and more yellow house nests. This likely suggests that the nitrite and nitrate contents have correlations with edible bird’s nests colour. Correlations studies suggested that the nitrite content had high correlations with colour parameters, L∗a∗b∗ of edible bird’s nests at significant level of P < 0.10. These findings suggest that edible bird’s nests’ colour may be a useful indicator for measuring nitrite and nitrate contaminations.

  3. Competitive and Cooperative Effects during Nickel Adsorption to Iron Oxides in the Presence of Oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Elaine D. [Department of Earth and Planetary; Catalano, Jeffrey G. [Department of Earth and Planetary

    2017-08-09

    Iron oxides are ubiquitous in soils and sediments and play a critical role in the geochemical distribution of trace elements and heavy metals via adsorption and coprecipitation. The presence of organic acids may potentially alter how metals associate with iron oxide minerals through a series of cooperative or competitive processes: solution complexation, ternary surface complexation, and surface site competition. The macroscopic and molecular-scale effects of these processes were investigated for Ni adsorption to hematite and goethite at pH 7 in the presence of oxalate. The addition of this organic acid suppresses Ni uptake on both minerals. Aqueous speciation suggests that this is dominantly the result of oxalate complexing and solubilizing Ni. Comparison of the Ni surface coverage to the concentration of free (uncomplexed) Ni2+ in solution suggests that the oxalate also alters Ni adsorption affinity. EXAFS and ATR-FTIR spectroscopies indicate that these changes in binding affinity are due to the formation of Ni–oxalate ternary surface complexes. These observations demonstrate that competition between dissolved oxalate and the mineral surface for Ni overwhelms the enhancement in adsorption associated with ternary complexation. Oxalate thus largely enhances Ni mobility, thereby increasing micronutrient bioavailability and inhibiting contaminant sequestration.

  4. Experimental studies of methemoglobinemia due to percutaneous absorption of sodium nitrite.

    Science.gov (United States)

    Saito, T; Takeichi, S; Nakajima, Y; Yukawa, N; Osawa, M

    1997-01-01

    Methemoglobin formation caused by a liniment solution containing sodium nitrite (30 g/L and 140 g/L) was studied in rats with normal or abraded skin, by measuring the methemoglobin concentration before and after application of liniment solutions with differing nitrite concentration. Each liniment solution (120 microL) was applied. Methemoglobin was measured for 180 minutes using a hemoximeter. Simultaneously, arterial blood pressure and cutaneous blood flow was measured by laser Doppler flowmetry and a pressure transducer. After the application of each liniment solution to normal skin, the methemoglobin concentration was not significantly modified depending on the time after application. Application of liniment solution to abraded skin (140 g/L) resulted in a marked increase in methemoglobin concentration. A remarkable decrease in arterial blood pressure and subcutaneous blood flow were observed after application of liniment solution to abraded skin (140 g/L). Each of these findings are characteristic of nitrite and they imply the percutaneous absorption of nitrite. Regardless of the nitrite concentration, the methemoglobin concentration was consistently higher in abraded skin than in normal skin.

  5. Nitrogen removal and electricity production at a double-chamber microbial fuel cell with cathode nitrite denitrification.

    Science.gov (United States)

    Yu, Yangyang; Zhao, Jianqiang; Wang, Sha; Zhao, Huimin; Ding, Xiaoqian; Gao, Kun

    2017-12-01

    Double-chamber microbial fuel cell was applied to investigate the performance of the electricity production and nitrite denitrification through feeding nitrite into the cathode. Factors influencing denitrification performance and power production, such as external resistance, influent nitrite concentration and Nitrite Oxygen Bacteria inhibitors, were studied. The results show that when the concentration of nitrite nitrogen and external resistance were 100 mg L -1 and 10 Ω, respectively, the nitrite denitrification reached the best state. The NaN 3 can inhibit nitrite oxidation effectively; meanwhile, the nitrite denitrification with N 2 O as the final products was largely improved. The [Formula: see text] was reduced to [Formula: see text], causing the cathode denitrification coulombic efficiency to exceed 100%. In chemoautotrophic bio-nitrification, microorganisms may utilize H 2 O to oxidize nitrite under anaerobic conditions. Proteobacteria might play a major role in the process of denitrification in MFC.

  6. Relation between nitrate and nitrite food habits with lung cancer.

    Science.gov (United States)

    Karimzadeh, Laleh; Koohdani, Fariba; Siassi, Fereydoon; Mahmoudi, Mahmoud; Moslemi, Daryoush; Safari, Farid

    2012-01-01

    Nitrites, a probable human carcinogen, generate reactive nitrogen species that may cause damage to the lung. We evaluated the association between nutritional habits related to nitrite and nitrate intake and risk of lung cancer in Mazandaran, Northern Province of Iran. In this case-control study the two groups were matched for gender and age (+/- 5 years). A semi -quantitative food frequency questionnaire (FFQ) was used to collect dietary data about nutritional habits related to nitrate, nitrite, vitamins E and C intake, from 40 lung cancer cases and 40 control subjects admitted at Mazanaran hospitals. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of lung cancer using logistic regression. Mean score of nutritional habits in case group was significantly lower than that in control group (P less than or equal 0.001). We observed a positive association between animal sources of nitrate and nitrite intake (OR = 2.7, 95% CI: 0.13-0.96) and risk of lung cancer. Decreased risk of lung cancer was also observed with fruit intake (OR = 0.26, 95% CI: 1.3-11). Our results indicate a probable association between nutritional habits related to animal sources of nitrate and nitrite intake and the risk of lung cancer that requires to be confirmed by other studies.

  7. Isolation and characterization of mesophilic, oxalate-degrading Streptomyces from plant rhizosphere and forest soils

    Science.gov (United States)

    Sahin, Nurettin

    2004-10-01

    The present work was aimed at the isolation of additional new pure cultures of oxalate-degrading Streptomyces and its preliminary characterization for further work in the field of oxalate metabolism and taxonomic studies. Mesophilic, oxalate-degrading Streptomyces were enriched and isolated from plant rhizosphere and forest soil samples. Strains were examined for cultural, morphological (spore chain morphology, spore mass colour, diffusible and melanin pigment production), physiological (antibiosis, growth in the presence of inhibitory compounds, assimilation of organic acids and enzyme substrates) and chemotaxonomic characters (cellular lipid components and diagnostic cell-wall diamino acid). The taxonomic data obtained were analysed by using the simple matching (SSM) and Jaccard (SJ) coefficients, clustering was achieved using the UPGMA algorithm. All strains were able to utilize sodium-, potassium-, calcium- and ammonium-oxalate salts. Based on the results of numerical taxonomy, isolates were grouped into five cluster groups with a ≥70% SSM similarity level. Streptomyces rochei was the most common of the cluster groups, with a Willcox probability of P>0.8. Streptomyces antibioticus, S. anulatus, S. fulvissimus, S. halstedii and S. violaceusniger are newly reported as oxalate-utilizing Streptomyces.

  8. Shewanella oneidensis cytochrome c nitrite reductase (ccNiR) does not disproportionate hydroxylamine to ammonia and nitrite, despite a strongly favorable driving force.

    Science.gov (United States)

    Youngblut, Matthew; Pauly, Daniel J; Stein, Natalia; Walters, Daniel; Conrad, John A; Moran, Graham R; Bennett, Brian; Pacheco, A Andrew

    2014-04-08

    Cytochrome c nitrite reductase (ccNiR) from Shewanella oneidensis, which catalyzes the six-electron reduction of nitrite to ammonia in vivo, was shown to oxidize hydroxylamine in the presence of large quantities of this substrate, yielding nitrite as the sole free nitrogenous product. UV-visible stopped-flow and rapid-freeze-quench electron paramagnetic resonance data, along with product analysis, showed that the equilibrium between hydroxylamine and nitrite is fairly rapidly established in the presence of high initial concentrations of hydroxylamine, despite said equilibrium lying far to the left. By contrast, reduction of hydroxylamine to ammonia did not occur, even though disproportionation of hydroxylamine to yield both nitrite and ammonia is strongly thermodynamically favored. This suggests a kinetic barrier to the ccNiR-catalyzed reduction of hydroxylamine to ammonia. A mechanism for hydroxylamine reduction is proposed in which the hydroxide group is first protonated and released as water, leaving what is formally an NH2(+) moiety bound at the heme active site. This species could be a metastable intermediate or a transition state but in either case would exist only if it were stabilized by the donation of electrons from the ccNiR heme pool into the empty nitrogen p orbital. In this scenario, ccNiR does not catalyze disproportionation because the electron-donating hydroxylamine does not poise the enzyme at a sufficiently low potential to stabilize the putative dehydrated hydroxylamine; presumably, a stronger reductant is required for this.

  9. Color compensation in nitrite-reduced meat batters incorporating paprika or tomato paste.

    Science.gov (United States)

    Bázan-Lugo, Eduardo; García-Martínez, Ignacio; Alfaro-Rodríguez, Rosa Hayde; Totosaus, Alfonso

    2012-06-01

    Nitrite is a key ingredient the manufacture of meat products, forming a stable pink color characteristic of cured products, retarding the development of rancidity and off-odors and flavors during storage, and preventing microbial growth. The negative aspects of nitrite and the demands for healthy foods result in the need to reduce nitrite in cured meat products. Paprika or tomato has been employed as natural pigments in meat products. The objective of this work was to determine the effect of incorporating paprika powder or tomato paste on the texture, rancidity and instrumental and sensory color compensation in nitrite-reduced meat batters. Addition of tomato paste improved moisture content, resulting in harder but less cohesive samples as compared to control and paprika-containing meat batters. Color characteristics of reduced nitrite samples obtained higher a* red coloration (8.9 for paprika and 7.7-8.0 for tomato paste), as compared to control samples (5.65). Instrumental color was low in control samples, with high values for tomato paste and paprika samples. Nonetheless, tomato paste used to compensate color in nitrite-reduced meat batters was ranked closer to the control sample in sensory evaluation. Color characteristics-instrumental and sensory-in these kinds of meat products were enhanced by the addition of 2.5-3.0% of tomato paste, presenting results close to the non-reduced nitrite control. Similarly, antioxidant components of tomato paste or paprika reduced lipid oxidation. Nitrite reduction from 150 to 100 ppm could be achieved employing tomato paste as a natural pigment to improve color and texture. Copyright © 2011 Society of Chemical Industry.

  10. Internalization of Calcium Oxalate Calculi Developed in Narrow Cavities

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    Fèlix Grases

    2014-03-01

    Full Text Available We describe the case of a patient with calcium oxalate monohydrate and calcium oxalate dihydrate calculi occluded in cavities. All those calculi were located inside narrow cavities covered with a thin epithelium that permits their visualization. Urinary biochemical analysis showed high calciuria, not hypercalciuria, hypocitraturia, and a ratio [calcium]/[citrate] >0.33. The existence of cavities of very low urodynamic efficacy was decisive in the formation of such calculi. It is important to emphasize that we observed a thin epithelium covering such cavities, demonstrating that this epithelium may be formed after the development of the calculi through a re-epithelialization process.

  11. Nitrate Reduction to Nitrite, Nitric Oxide and Ammonia by Gut Bacteria under Physiological Conditions

    Science.gov (United States)

    Tiso, Mauro; Schechter, Alan N.

    2015-01-01

    The biological nitrogen cycle involves step-wise reduction of nitrogen oxides to ammonium salts and oxidation of ammonia back to nitrites and nitrates by plants and bacteria. Neither process has been thought to have relevance to mammalian physiology; however in recent years the salivary bacterial reduction of nitrate to nitrite has been recognized as an important metabolic conversion in humans. Several enteric bacteria have also shown the ability of catalytic reduction of nitrate to ammonia via nitrite during dissimilatory respiration; however, the importance of this pathway in bacterial species colonizing the human intestine has been little studied. We measured nitrite, nitric oxide (NO) and ammonia formation in cultures of Escherichia coli, Lactobacillus and Bifidobacterium species grown at different sodium nitrate concentrations and oxygen levels. We found that the presence of 5 mM nitrate provided a growth benefit and induced both nitrite and ammonia generation in E.coli and L.plantarum bacteria grown at oxygen concentrations compatible with the content in the gastrointestinal tract. Nitrite and ammonia accumulated in the growth medium when at least 2.5 mM nitrate was present. Time-course curves suggest that nitrate is first converted to nitrite and subsequently to ammonia. Strains of L.rhamnosus, L.acidophilus and B.longum infantis grown with nitrate produced minor changes in nitrite or ammonia levels in the cultures. However, when supplied with exogenous nitrite, NO gas was readily produced independently of added nitrate. Bacterial production of lactic acid causes medium acidification that in turn generates NO by non-enzymatic nitrite reduction. In contrast, nitrite was converted to NO by E.coli cultures even at neutral pH. We suggest that the bacterial nitrate reduction to ammonia, as well as the related NO formation in the gut, could be an important aspect of the overall mammalian nitrate/nitrite/NO metabolism and is yet another way in which the microbiome

  12. Nitrate reduction to nitrite, nitric oxide and ammonia by gut bacteria under physiological conditions.

    Directory of Open Access Journals (Sweden)

    Mauro Tiso

    Full Text Available The biological nitrogen cycle involves step-wise reduction of nitrogen oxides to ammonium salts and oxidation of ammonia back to nitrites and nitrates by plants and bacteria. Neither process has been thought to have relevance to mammalian physiology; however in recent years the salivary bacterial reduction of nitrate to nitrite has been recognized as an important metabolic conversion in humans. Several enteric bacteria have also shown the ability of catalytic reduction of nitrate to ammonia via nitrite during dissimilatory respiration; however, the importance of this pathway in bacterial species colonizing the human intestine has been little studied. We measured nitrite, nitric oxide (NO and ammonia formation in cultures of Escherichia coli, Lactobacillus and Bifidobacterium species grown at different sodium nitrate concentrations and oxygen levels. We found that the presence of 5 mM nitrate provided a growth benefit and induced both nitrite and ammonia generation in E.coli and L.plantarum bacteria grown at oxygen concentrations compatible with the content in the gastrointestinal tract. Nitrite and ammonia accumulated in the growth medium when at least 2.5 mM nitrate was present. Time-course curves suggest that nitrate is first converted to nitrite and subsequently to ammonia. Strains of L.rhamnosus, L.acidophilus and B.longum infantis grown with nitrate produced minor changes in nitrite or ammonia levels in the cultures. However, when supplied with exogenous nitrite, NO gas was readily produced independently of added nitrate. Bacterial production of lactic acid causes medium acidification that in turn generates NO by non-enzymatic nitrite reduction. In contrast, nitrite was converted to NO by E.coli cultures even at neutral pH. We suggest that the bacterial nitrate reduction to ammonia, as well as the related NO formation in the gut, could be an important aspect of the overall mammalian nitrate/nitrite/NO metabolism and is yet another way in

  13. Color Developing Capacity of Plasma-treated Water as a Source of Nitrite for Meat Curing.

    Science.gov (United States)

    Jung, Samooel; Kim, Hyun Joo; Park, Sanghoo; Yong, Hae In; Choe, Jun Ho; Jeon, Hee-Joon; Choe, Wonho; Jo, Cheorun

    2015-01-01

    The interaction of plasma with liquid generates nitrogen species including nitrite (NO(-) 2). Therefore, the color developing capacity of plasma-treated water (PTW) as a nitrite source for meat curing was investigated in this study. PTW, which is generated by surface dielectric barrier discharge in air, and the increase of plasma treatment time resulted in increase of nitrite concentration in PTW. The PTW used in this study contains 46 ppm nitrite after plasma treatment for 30 min. To evaluate the effect of PTW on the cured meat color, meat batters were prepared under three different conditions (control, non-cured meat batter; PTW, meat batter cured with PTW; Sodium nitrite, meat batter cured with sodium nitrite). The meat batters were vacuum-packaged and cooked in a water-bath at 80℃ for 30 min. The typical color of cured meat developed in cooked meat batter treated with sodium nitrite or PTW. The lightness (L*) and yellowness (b*) values were similar in all conditions, whereas, the redness (a*) values of cooked meat batter with PTW and sodium nitrite (pnitrite source in the curing process of meat without addition of other nitrite sources.

  14. Effect of Nitrite Inhibitor on the Macrocell Corrosion Behavior of Reinforcing Steel

    Directory of Open Access Journals (Sweden)

    Zhonglu Cao

    2015-01-01

    Full Text Available The effect of nitrite ions on the macrocell corrosion behavior of reinforcing steel embedded in cement mortar was investigated by comparing and analyzing the macrocell corrosion current, macrocell polarization ratios, and slopes of anodic and cathodic steels. Based on the experimental results, the relationship between macrocell potential difference and macrocell current density was analyzed, and the mechanism of macrocell corrosion affected by nitrite ions was proposed. The results indicated that nitrite ions had significant impact on the macrocell polarization ratios of cathode and anode. The presence of nitrite could reduce the macrocell current by decreasing the macrocell potential difference and increasing the macrocell polarization resistance of the anode.

  15. Acute, Sub-lethal Cyanide Poisoning in Mice is Ameliorated by Nitrite Alone: Complications Arising from Concomitant Administration of Nitrite and Thiosulfate as an Antidotal Combination

    Science.gov (United States)

    Cambal, Leah K.; Swanson, Megan R.; Yuan, Quan; Weitz, Andrew C.; Li, Hui-Hua; Pitt, Bruce R.; Pearce, Linda L.; Peterson, Jim

    2011-01-01

    Sodium nitrite alone is shown to ameliorate sub-lethal cyanide toxicity in mice when given from ~1 hour before until 20 minutes after the toxic dose as demonstrated by the recovery of righting ability. An optimum dose (12 mg/kg) was determined to significantly relieve cyanide toxicity (5.0 mg/kg) when administered to mice intraperitoneally. Nitrite so administered was shown to rapidly produce NO in the bloodsteam as judged by the dose dependent appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin. It is argued that antagonism of cyanide inhibition of cytochrome c oxidase by NO is the crucial antidotal activity rather than the methemoglobin-forming action of nitrite. Concomitant addition of sodium thiosulfate to nitrite-treated blood resulted in the detection of sulfidomethemoblobin by EPR spectroscopy. Sulfide is a product of thiosulfate hydrolysis and, like cyanide, is known to be a potent inhibitor of cytochrome c oxidase; the effects of the two inhibitors being essentially additive under standard assay conditions, rather than dominated by either one. The findings afford a plausible explanation for an observed detrimental effect in mice associated with the use of the standard nitrite-thiosulfate combination therapy at sub-lethal levels of cyanide intoxication. PMID:21534623

  16. Performance of denitrifying microbial fuel cell with biocathode over nitrite

    Directory of Open Access Journals (Sweden)

    Zhao eHuimin

    2016-03-01

    Full Text Available Microbial fuel cell (MFC with nitrite as an electron acceptor in cathode provided a new technology for nitrogen removal and electricity production simultaneously. The influences of influent nitrite concentration and external resistance on the performance of denitrifying MFC were investigated. The optimal effectiveness were obtained with the maximum total nitrogen (TN removal rate of 54.80±0.01 g m-3 d-1. It would be rather desirable for the TN removal than electricity generation at lower external resistance. Denaturing gradient gel electrophoresis suggested that Proteobacteria was the predominant phylum, accounting for 35.72%. Thiobacillus and Afipia might benefit to nitrite removal. The presence of nitrifying Devosia indicated that nitrite was oxidized to nitrate via a biochemical mechanism in the cathode. Ignavibacterium and Anaerolineaceae was found in the cathode as a heterotrophic bacterium with sodium acetate as substrate, which illustrated that sodium acetate in anode was likely permeated through proton exchange membrane to the cathode .

  17. Diminution of oxalate induced renal tubular epithelial cell injury and inhibition of calcium oxalate crystallization in vitro by aqueous extract of Tribulus terrestris.

    Science.gov (United States)

    Aggarwal, A; Tandon, S; Singla, S K; Tandon, C

    2010-01-01

    Recurrence and persistent side effects of present day treatment for urolithiasis restrict their use, so an alternate solution, using phytotherapy is being sought. The present study attempted to evaluate the antilithiatic properties of Tribulus terrestris commonly called as "gokhru" which is often used in ayurveda to treat various urinary diseases including urolithiasis. The activity of Tribulus terrestris was investigated on nucleation and the growth of the calcium oxalate (CaOx) crystals as well as on oxalate induced cell injury of NRK 52E renal epithelial cells. Tribulus terrestris extract exhibited a concentration dependent inhibition of nucleation and the growth of CaOx crystals. When NRK-52E cells were injured by exposure to oxalate for 72 h, Tribulus terrestris extract prevented the injury in a dose-dependent manner. On treatment with the different concentrations of the plant, the cell viability increased and lactate dehydrogenase release decreased in a concentration dependent manner. The current data suggests that Tribulus terrestris extract not only has a potential to inhibit nucleation and the growth of the CaOx crystals but also has a cytoprotective role. Our results indicate that it could be a potential candidate for phytotherapy against urolithiasis.

  18. Influencing the solubility of oxalates for the preparation of ceramic powders from mixed precipitates

    International Nuclear Information System (INIS)

    Krueger, C.; Fischer, S.; Fischer, St.; Chebani, M.Kh.

    1991-01-01

    Based on investigations of the solubility of oxalate with 140 Ba, 64 Cu and 59 Fe, techniques for quantitative oxalate coprecipitation were developed. Addition of organic solvents lowers the solubility and leads to a smaller particle size of products. (orig.) [de

  19. MONITORING KADAR NITRIT DAN NITRAT PADA AIR SUMUR DI DAERAH CATUR TUNGGAL YOGYAKARTA DENGAN METODE SPEKTROFOTOMETRI UV-VIS (Monitoring of Nitrite and Nitrate Content in Ground Water of Catur Tunggal Region of Yogyakarta by UV-VIS Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Setiowati Setiowati

    2016-07-01

    Full Text Available ABSTRAK Metode analisis nitrit dan nitrat perlu dikembangkan untuk memonitor kualitas air minum. Kualitas air sumur untuk parameter nitrit dan nitrat dipengaruhi oleh kondisi lingkungan dan kedalaman air sumur.Penelitian ini bertujuan menganalisis nitrit dan nitrat menggunakan asam p-aminobenzoat (PABA pada air sumur di daerah perkotaan Yogyakarta. Analisis nitrit didasarkan pada reaksi antara ion nitrit dengan PABA yang membentuk senyawa azo dengan panjang gelombang maksimum 546 nm. Kedalaman air sumur di daerah Catur Tunggal rata-rata > 10 m. Kadar nitrit dan nitrat pada air sumur adalah 0,05-0,09 dan 8,22-36,58 mg/L. Kadar nitrit dan nitrat tersebut memenuhi baku mutu dan aman untuk dikonsumsi. Konsentrasi nitrit dan nitrat pada air RO adalah 0,05 dan 2,72-59,57 mg/L. Kadar nitrit pada air RO tidak memenuhi baku mutu sedangkan kadar nitrat memenuhi baku mutu kecuali RO 5. ABSTRACT The method for analysis nitrite and nitrate had to developed to monitor the drinking water quality. The well water quality, especially for nitrite and nitrate were influenced by environmental conditions and depth of well. This study aims to analyze nitrite and nitrate using p-aminobenzoic acid (PABA in ground water at urban areas of Yogyakarta. The analysis was based on the reaction between nitrite ions with PABA which form azo compounds with a maximum wavelength of 546 nm. The depth of wells at Catur Tunggal were more than 10 m. Concentration of nitrite and nitrate in well water were 0.05 to 0.09 and 8.22 to 36.58 mg / L. The concentrations met the standard for drinking water quality and was safe for consumption. The concentration of nitrite and nitrate in reverse osmosis (RO water were 0.05 and 2.72 to 59.57 mg / L. The concentration of nitrite did not meet the standard for drinking water quality while the concentration of nitrate met the standard for drinking water quality except RO 5.

  20. A comparative study of nitrite reduction by synthetic and biogenic Fe(II-III) hydroxysalts green rusts: Evidence for hydroxyl-nitrite green rust formation as an intermediate reaction product.

    Science.gov (United States)

    Ona-Nguema, G.; Guerbois, D.; Morin, G.; Zhang, Y.; Noel, V.; Brest, J.

    2013-12-01

    The occurrence of high nitrite concentrations as a result of anthropogenic activities is an important water quality concern as it is highly toxic to human and fauna, and it is used as a nitrogen source for the assimilation process. The toxicity of nitrite is related to its transformation into carcinogenic N-nitroso compounds, which are suspected to be responsible for some gastric cancers, and to its ability to convert the hemoglobin to methaemoglobin what is then unable to fix oxygen and to transport it to the tissues, involving hypoxia and the blue-baby syndrome [1]. To reduce the adverse effect of nitrite on human health and on macroalgal blooms, any process enhancing the transformation of nitrite ions to nitrogen gas is of interest for the remediation of natural environments. To achieve this purpose the use of processes involving Fe(II)-containing minerals could be considered as one of the best options. Green-rusts are mixed Fe(II-III) layered double hydroxides commonly found in anoxic zones of natural environments such as sediments and hydromorphic soils. In such anoxic environments, green rust minerals play an important role in the biogeochemical redox cycling of iron and nitrogen, and can affect the speciation and mobility of many organic and inorganic contaminants. The present study investigates the reduction of nitrite by two synthetic and two biogenic green rusts. On the one hand, Fe(II-III) hydroxychloride and Fe(II-III) hydroxycarbonate green rusts were used as synthetic interlayer forms of GR, which are referred to as ';syn-GR(CO3)' and ';syn-GR(Cl)', respectively. On the other hand, the study was performed with biogenic Fe(II-III) hydroxycarbonate green rusts obtained from the bioreduction of two ferric precursors, either Fe(III)-oxyhydroxycarbonate or lepidocrocite; these biogenic green rusts are referred to as ';bio-GR(CO3)F' and ';bio-GR(CO3)L', respectively. For synthetic green rusts, results showed that the oxidation of both syn-GR(CO3) and syn

  1. Nitrite toxicity assessment in Danio rerio and Poecilia reticulata

    Directory of Open Access Journals (Sweden)

    Petra Doleželová

    2011-01-01

    Full Text Available Nitrite is a natural component of the nitrogen cycle in the environment. Although it usually occurs in low concentrations, elevated concentrations caused by effluents or affected nitrification process can lead to serious health deterioration of fish. Two aquarium fish zebrafish (Danio rerio and guppy (Poecilia reticulata are recommended to use as model organisms in toxicity tests. However, their sensitivity to nitrite can differ. The aim of this study was to define acute toxicity of nitrite by the semistatic method according to OECD No. 203 (Fish, Acute toxicity test. The series of 4 acute toxicity tests was performed, with 10 fish of both species used for each concentration and for the control. The 96hLC50 NO2- value for D. rerio and P. reticulata was 242.55 ± 15.79 mg·l-1 and 30.2 ± 8.74 mg·l-1, respectively. We have proved significant difference (p D. rerio and P. reticulata. The results showed different sensitivities to nitrites in tested fish species, which could be related to species-specific branchial chloride uptake mechanism. This is the first study on this fish species.

  2. Poppers: epidemiology and clinical management of inhaled nitrite abuse.

    Science.gov (United States)

    Romanelli, Frank; Smith, Kelly M; Thornton, Alice C; Pomeroy, Claire

    2004-01-01

    Commonly referred to as "poppers," inhaled nitrites have a long history of abuse. Poppers are rapid-onset, short-acting potent vasodilators that produce a rush characterized by warm sensations and feelings of dizziness. Poppers sometimes are used to facilitate anal intercourse because of their actions on the anal sphincter. Epidemiologically, the frequent use of nitrites by men who have sex with men has led some experts to implicate these chemicals in the pathogenesis of Kaposi's sarcoma and acquired immunodeficiency syndrome. Controlled clinical trials to examine this potential correlation have not been conducted, and the use of nitrites simply may be a marker for other high-risk behaviors such as unprotected sex. Although regulated in the United States, many nitrite compounds and isomers are sold at various venues including bars, bookstores, and over the Internet. Adverse effects associated with these products vary from mild allergic reactions to life-threatening methemoglobinemia. The potential for drug-drug interactions and a propensity toward unsafe sex also exist. Clinicians should be familiar with the populations most likely to abuse these agents and with the clinical effects and management guidelines for acute ingestions.

  3. Changes in plasma and urinary nitrite after birth in premature infants at risk for necrotizing enterocolitis

    Science.gov (United States)

    Pun, Priti; Jones, Jesica; Wolfe, Craig; Deming, Douglas D.; Power, Gordon G.; Blood, Arlin B.

    2016-01-01

    Background Plasma nitrite serves as a reservoir of nitric oxide (NO) bioactivity. Because nitrite ingestion is markedly lower in newborns than adults, we hypothesized plasma nitrite levels would be lower in newborns than in adults, and that infants diagnosed with necrotizing enterocolitis (NEC), a disease characterized by ischemia and bacterial invasion of intestinal walls, would have lower levels of circulating nitrite in the days prior to diagnosis. Methods Single blood and urine samples were collected from 9 term infants and 12 adults, 72 preterm infants every 5 d for 3 wk, and from 13 lambs before and after cord occlusion. Results Nitrite fell 50% relative to cord levels in the first day after birth; and within 15 min after cord occlusion in lambs. Urinary nitrite was higher in infants than adults. Plasma and urinary nitrite levels in infants who developed NEC were similar to those of preterm control infants on days 1 and 5, but significantly elevated at 15 and 20 d after birth. Conclusion Plasma nitrite falls dramatically at birth while newborn urinary nitrite levels are significantly greater than adults. Acute NEC is associated with elevated plasma and urinary nitrite levels. PMID:26539663

  4. The oxalic acid biosynthetic activity of Burkholderia mallei is encoded by a single locus

    Science.gov (United States)

    Although it is known that oxalic acid provides a selective advantage to the secreting microbe, our understanding of how this acid is biosynthesized remains incomplete. This study reports the identification, cloning, and partial characterization of the oxalic acid biosynthetic enzyme from the animal ...

  5. Electrodeposition of gold from formaldehyde-sulfite baths: bath stability and deposits characterization

    Directory of Open Access Journals (Sweden)

    Juliana L. Cardoso

    2011-01-01

    Full Text Available It was investigated Au(I-sulfite baths containing formaldehyde. As a result, high stability was achieved for baths containing formaldehyde concentration close to 10 mL L-1 with a lifetime superior to 600 days. On the other hand, cyclic voltammograms indicated that the increase of formaldehyde concentration in the bath promotes decreasing of the maximum cathodic current, so that, if the formaldehyde concentration is high, the surface areal concentration of gold will be low. Also, the lowest surface roughness was obtained for 10 mL L-1 of formaldehyde.

  6. Pathological features of oxalate nephrosis in a population of koalas (Phascolarctos cinereus) in South Australia.

    Science.gov (United States)

    Speight, K N; Boardman, W; Breed, W G; Taggart, D A; Woolford, L; Haynes, J I

    2013-03-01

    The wild and captive koala population of the Mt Lofty Ranges in South Australia has a high level of renal dysfunction in which crystals consistent with calcium oxalate have been observed in the kidneys. This study aimed to describe the pathological features of the renal disease in this population, confirm the composition of renal crystals as calcium oxalate, and determine whether any age or sex predispositions exist for this disease. A total of 51 koalas (28 wild rescues, 23 captive) were examined at necropsy, of which 28 (55%) were found to have gross and/or histological evidence of oxalate nephrosis. Histopathological features included intratubular and interstitial inflammation, tubule dilation, glomerular atrophy, tubule loss, and cortical fibrosis. Calcium oxalate crystals were demonstrated using a combination of polarization microscopy, alizarin red S staining, infrared spectroscopy, and energy-dispersive X-ray analysis with scanning electron microscopy. Uric acid and phosphate deposits were also shown to be present but were associated with minimal histopathological changes. No significant differences were found between the numbers of affected captive and wild rescued koalas; also, there were no sex or age predispositions identified, but it was found that oxalate nephrosis may affect koalas <2 years of age. The findings of this study suggest that oxalate nephrosis is a leading disease in this koala population. Possible causes of this disease are currently under investigation.

  7. Enzymatic mechanism of oxalate production in the TCA and glyoxylate pathways using various isolates of Antrodia radiculosa

    Science.gov (United States)

    K.M. Jenkins; S.V. Diehl; C.A. Clausen; F. Green

    2011-01-01

    Brown-rot fungi produce oxalate in large amounts; however, levels of accumulation and function vary by species. Copper-tolerant fungi, like Antrodia radiculosa, produce and accumulate high levels of oxalate in response to copper. Oxalate biosynthesis in copper-tolerant fungi has been linked to the glyoxylate and tricarboxylic acid (TCA) cycles. Within these two cycles...

  8. Hypoxia tolerance, nitric oxide, and nitrite: Lessons from extreme animals

    DEFF Research Database (Denmark)

    Fago, Angela; B. Jensen, Frank

    2015-01-01

    survival resides in concerted physiological responses, including strong metabolic depression, protection against oxidative damage and – in air breathing animals - redistribution of blood flow. Each of these responses is known to be tightly regulated by nitric oxide (NO) and during hypoxia by its metabolite...... nitrite. The aim of this review is to highlight recent work illustrating the widespread roles of NO and nitrite in the tolerance to extreme oxygen deprivation, in particular in the red-eared slider turtle and crucian carp, but also in diving marine mammals. The emerging picture underscores the importance...... of NO and nitrite signaling in the adaptive response to hypoxia in vertebrate animals....

  9. Role of xanthine oxidoreductase in the anti-thrombotic effects of nitrite in rats in vivo.

    Science.gov (United States)

    Kramkowski, K; Leszczynska, A; Przyborowski, K; Kaminski, T; Rykaczewska, U; Sitek, B; Zakrzewska, A; Proniewski, B; Smolenski, R T; Chabielska, E; Buczko, W; Chlopicki, S

    2016-01-01

    The mechanisms underlying nitrite-induced effects on thrombosis and hemostasis in vivo are not clear. The goal of the work described here was to investigate the role of xanthine oxidoreductase (XOR) in the anti-platelet and anti-thrombotic activities of nitrite in rats in vivo. Arterial thrombosis was induced electrically in rats with renovascular hypertension by partial ligation of the left renal artery. Sodium nitrite (NaNO2, 0.17 mmol/kg twice daily for 3 days, p.o) was administered with or without one of the XOR-inhibitors: allopurinol (ALLO) and febuxostat (FEB) (100 and 5 mg/kg, p.o., for 3 days). Nitrite treatment (0.17 mmol/kg), which was associated with a significant increase in NOHb, nitrite/nitrate plasma concentration, resulted in a substantial decrease in thrombus weight (TW) (0.48 ± 0.03 mg vs. vehicle [VEH] 0.88 ± 0.08 mg, p < 0.001) without a significant hypotensive effect. The anti-thrombotic effect of nitrite was partially reversed by FEB (TW = 0.63 ± 0.06 mg, p < 0.05 vs. nitrites), but not by ALLO (TW = 0.43 ± 0.02 mg). In turn, profound anti-platelet effect of nitrite measured ex vivo using collagen-induced whole-blood platelet aggregation (70.5 ± 7.1% vs. VEH 100 ± 4.5%, p < 0.05) and dynamic thromboxaneB2 generation was fully reversed by both XOR-inhibitors. In addition, nitrite decreased plasminogen activator inhibitor-1 concentration (0.47 ± 0.13 ng/ml vs. VEH 0.62 ± 0.04 ng/ml, p < 0.05) and FEB/ALLO reversed this effect. In vitro the anti-platelet effect of nitrite (1 mM) was reversed by FEB (0.1 mM) under hypoxia (0.5%O2) and normoxia (20%O2). Nitrite treatment had no effect on coagulation parameters. In conclusion, the nitrite-induced anti-platelet effect in rats in vivo is mediated by XOR, but XOR does not fully account for the anti-thrombotic effects of nitrite.

  10. Electrochemical Single‐Molecule AFM of the Redox Metalloenzyme Copper Nitrite Reductase in Action

    DEFF Research Database (Denmark)

    Hao, Xian; Zhang, Jingdong; Christensen, Hans Erik Mølager

    2012-01-01

    We studied the electrochemical behavior of the redox metalloenzyme copper nitrite reductase (CNiR, Achromobacter xylosoxidans) immobilized on a Au(111)‐electrode surface modified by a self‐assembled cysteamine molecular monolayer (SAM) using a combination of cyclic voltammetry and electrochemically......‐controlled atomic force microscopy (in situ AFM). The enzyme showed no voltammetric signals in the absence of nitrite substrate, whereas a strong reductive electrocatalytic signal appeared in the presence of nitrite. Such a pattern is common in protein film and monolayer voltammetry and points to conformational...... in the presence of nitrite. No change in size was observed in the absence of nitrite over the same potential range. The enzyme size variation is suggested to offer clues to the broadly observed substrate triggering in metalloenzyme monolayer voltammetry....

  11. Stability-indicating RP-HPLC method for the simultaneous determination of escitalopram oxalate and clonazepam.

    Science.gov (United States)

    Kakde, Rajendra B; Satone, Dinesh D; Gadapayale, Kamalesh K; Kakde, Megha G

    2013-07-01

    The objective of the current study was to develop a validated, specific stability-indicating reversed-phase liquid chromatographic (LC) method for the quantitative determination of escitalopram oxalate and clonazepam and their related substances in bulk drugs and pharmaceutical dosage forms in the presence of degradation products. Forced degradation studies were performed on the pure drugs of escitalopram oxalate and clonazepam, as per the stress conditions prescribed by the International Conference on Harmonization (ICH) using acid, base, oxidation, thermal stress and photolytic degradation to show the stability-indicating power of the method. Significant degradation was observed during acid and alkaline hydrolysis and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies. Good resolution between the peaks corresponded to the active pharmaceutical ingredients, escitalopram oxalate and clonazepam, and degradation products from the analyte were achieved on an ODS Hypersil C18 column (250 × 4.6 mm) using a mobile phase consisting of a mixture of acetonitrile-50 mM phosphate buffer + 10 mM triethylamine (70:30, v/v). The detection was conducted at 268 nm. The limit of detection and the limit of quantitation for escitalopram oxalate and clonazepam were established. The stress test solutions were assayed against the qualified working standards of escitalopram oxalate and clonazepam, which indicated that the developed LC method was stability-indicating. Validation of the developed LC method was conducted as per ICH requirements. The developed LC method was found to be suitable to check the quality of bulk samples of escitalopram oxalate and clonazepam.

  12. Iron(II) porphyrins induced conversion of nitrite into nitric oxide: A computational study.

    Science.gov (United States)

    Zhang, Ting Ting; Liu, Yong Dong; Zhong, Ru Gang

    2015-09-01

    Nitrite reduction to nitric oxide by heme proteins was reported as a protective mechanism to hypoxic injury in mammalian physiology. In this study, the pathways of nitrite reduction to nitric oxide mediated by iron(II) porphyrin (P) complexes, which were generally recognized as models for heme proteins, were investigated by using density functional theory (DFT). In view of two type isomers of combination of nitrite and Fe(II)(P), N-nitro- and O-nitrito-Fe(II)-porphyrin complexes, and two binding sites of proton to the different O atoms of nitrite moiety, four main pathways for the conversion of nitrite into nitric oxide mediated by iron(II) porphyrins were proposed. The results indicate that the pathway of N-bound Fe(II)(P)(NO2) isomer into Fe(III)(P)(NO) and water is similar to that of O-bound isomer into nitric oxide and Fe(III)(P)(OH) in both thermodynamical and dynamical aspects. Based on the initial computational studies of five-coordinate nitrite complexes, the conversion of nitrite into NO mediated by Fe(II)(P)(L) complexes with 14 kinds of proximal ligands was also investigated. Generally, the same conclusion that the pathways of N-bound isomers are similar to those of O-bound isomer was obtained for iron(II) porphyrin with ligands. Different effects of ligands on the reduction reactions were also found. It is notable that the negative proximal ligands can improve reactive abilities of N-nitro-iron(II) porphyrins in the conversion of nitrite into nitric oxide compared to neutral ligands. The findings will be helpful to expand our understanding of the mechanism of nitrite reduction to nitric oxide by iron(II) porphyrins. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Retention and leaching of nitrite by municipal solid waste incinerator bottom ash under the landfill circumstance.

    Science.gov (United States)

    Yao, Jun; Kong, Qingna; Zhu, Huayue; Long, Yuyang; Shen, Dongsheng

    2015-01-01

    The retention and leaching of nitrite by municipal solid waste incinerator (MSWI) bottom ash could affect its migration in the landfill. In this study, the effect of the dosage of MSWI bottom ash as well as the variation of the landfill environmental parameters including pH, anions and organic matter on the nitrite retention and leaching behavior was investigated by batch experiments. The highest removal percentage (73.0%) of nitrite was observed when the dosage of MSWI bottom ash was 10 g L(-1) in 2 mg L(-1) nitrite solution. Further increase of the dosage would retard the retention, as the nitrite leaching from MSWI bottom ash was enhanced. The optimum retention of nitrite was observed when the pH was 5.0, while the leaching of nitrite showed a consistent reduction with the increase of pH. Besides, the presence of Cl(-), SO4(2)(-) and acetic acid could enhance the leaching of nitrite and mitigate the retention process. However, the retention of nitrite was enhanced by PO4(3)(-), which was probably due to the formation of the apatite, an active material for the adsorption of the nitrite. These results suggested that MSWI bottom ash could affect the migration of nitrite in the landfill, which was related to the variation of the landfill circumstance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Tumor induction in rats by feeding aminopyrine or oxytetracycline with nitrite

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, H W; Luinsky, W

    1975-01-01

    Sprague-Dawley rats were given combinations of aminopyrine or oxytetracycline and sodium nitrite in drinking water. Of 30 animals receiving 0.1 percent (1,000 ppm) of aminopyrine and sodium nitrite for 30 weeks, 29 died with hemangioendothelial sarcomas of the liver. The same tumor caused death in 26 of 30 animals that received 0.025 percent (250 ppm) of both aminopyrine and sodium nitrite for 50 weeks. No animals in a control group of the same size that received 0.1 percent aminopyrine for 30 weeks developed this tumor, although one-half of them were still alive 2 years after the experiment was begun. After feeding a comparable dose (0.1 percent) of oxytetracycline and sodium nitrite for 60 weeks, liver tumors were present in 4 of 30 rats (3 hepatocellular tumors and 1 cholangioma). Since aminopyrine has been widely used for medicinal purposes in the human population, it is possible that many people have been exposed to a potent carcinogen (dimethylnitrosamine) by its formation in vivo. It is not certain whether the result of feeding oxytetracycline and sodium nitrite indicates significant carcinogenicity of this combination. (auth)

  15. Oxalate-metabolising genes of the white-rot fungus Dichomitus squalens are differentially induced on wood and at high proton concentration.

    Directory of Open Access Journals (Sweden)

    Miia R Mäkelä

    Full Text Available Oxalic acid is a prevalent fungal metabolite with versatile roles in growth and nutrition, including degradation of plant biomass. However, the toxicity of oxalic acid makes regulation of its intra- and extracellular concentration crucial. To increase the knowledge of fungal oxalate metabolism, a transcriptional level study on oxalate-catabolising genes was performed with an effective lignin-degrading white-rot fungus Dichomitus squalens, which has demonstrated particular abilities in production and degradation of oxalic acid. The expression of oxalic-acid decomposing oxalate decarboxylase (ODC and formic-acid decomposing formate dehydrogenase (FDH encoding genes was followed during the growth of D. squalens on its natural spruce wood substrate. The effect of high proton concentration on the regulation of the oxalate-catabolising genes was determined after addition of organic acid (oxalic acid and inorganic acid (hydrochloric acid to the liquid cultures of D. squalens. In order to evaluate the co-expression of oxalate-catabolising and manganese peroxidase (MnP encoding genes, the expression of one MnP encoding gene, mnp1, of D. squalens was also surveyed in the solid state and liquid cultures. Sequential action of ODC and FDH encoding genes was detected in the studied cultivations. The odc1, fdh2 and fdh3 genes of D. squalens showed constitutive expression, whereas ODC2 and FHD1 most likely are the main responsible enzymes for detoxification of high concentrations of oxalic and formic acids. The results also confirmed the central role of ODC1 when D. squalens grows on coniferous wood. Phylogenetic analysis revealed that fungal ODCs have evolved from at least two gene copies whereas FDHs have a single ancestral gene. As a conclusion, the multiplicity of oxalate-catabolising genes and their differential regulation on wood and in acid-amended cultures of D. squalens point to divergent physiological roles for the corresponding enzymes.

  16. Continuous plutonium(IV) oxalate precipitation, filtration, and calcination process. [From product streams from Redox, Purex, or Recuplex solvent extraction plants

    Energy Technology Data Exchange (ETDEWEB)

    Beede, R L

    1956-09-27

    A continuous plutonium (IV) oxalate precipitation, filtration, and calcination process has been developed. Continuous and batch decomposition of the oxalate in the filtrates has been demonstrated. The processes have been demonstrated in prototype equipment. Plutonium (IV) oxalate was precipitated continuously at room temperature by the concurrent addition of plutonium (IV) nitrate feed and oxalic acid into the pan of a modified rotary drum filter. The plutonium (IV) oxalate was calcined to plutonium dioxide, which could be readily hydrofluorinated. Continuous decomposition of the oxalate in synthetic plutonium (IV) oxalate filtrates containing plutonium (IV) oxalate solids was demonstrated using co-current flow in a U-shaped reactor. Feeds containing from 10 to 100 g/1 Pu, as plutonium (IV) nitrate, and 1.0 to 6.5 M HNO/sub 3/, respectively, can be processed. One molar oxalic acid is used as the precipitant. Temperatures of 20 to 35/sup 0/C for the precipitation and filtration are satisfactory. Plutonium (IV) oxalate can be calcined at 300 to 400/sup 0/C in a screw-type drier-calciner to plutonium dioxide and hydrofluorinated at 450 to 550/sup 0/C. Plutonium dioxide exceeding purity requirements has been produced in the prototype equipment. Advantages of continuous precipitation and filtration are: uniform plutonium (IV) oxalate, improved filtration characteristics, elimination of heating and cooling facilities, and higher capacities through a single unit. Advantages of the screw-type drier-calciner are the continuous production of an oxide satisfactory for feed for the proposed plant vibrating tube hydrofluorinator, and ease of coupling continuous precipitation and filtration to this proposed hydrofluorinator. Continuous decomposition of oxalate in filtrates offers advantages in decreasing filtrate storage requirements when coupled to a filtrate concentrator. (JGB)

  17. Nisin: a possible alternative or adjunct to nitrite in the preservation of meats.

    Science.gov (United States)

    Rayman, M K; Aris, B; Hurst, A

    1981-01-01

    Nisin at 75 ppm (75 microgram/g) was superior to 150 ppm of nitrite in inhibiting outgrowth of Clostridium sporogenes PA3679 spores in meat slurries, which had been heated to simulate the process used for cooked ham. The inhibitory activity of nisin decreased as the spore load or pH of the slurries increased. Unlike nitrite, inhibition by nisin was unaffected by high levels of iron either as a constituent of meats or when added as an iron salt. In slurries treated with 75 ppm of nisin, refrigerated storage for 56 days resulted in depletion of nisin to a level low enough to allow outgrowth within 3 to 10 days if the slurries were subsequently abused at 35 degrees C. In contrast, a combination of 40 ppm of nitrite and either 75 or 100 ppm of nisin almost completely inhibited outgrowth in these slurries. The nisin-nitrite combination appeared to have a synergistic effect, and the low concentration of nitrite was sufficient to preserve the color in meats similar to that of products cured with 150 ppm of nitrite. PMID:7195188

  18. Dramatic loss of comammox Nitrospira associated with long-term nitrite feeding

    DEFF Research Database (Denmark)

    Kinnunen, Marta; Palomo, Alejandro; Dechesne, Arnaud

    Until recently, nitrification was thought to be a strict two-step process where ammonia was first oxidized to nitrite by ammonia-oxidizing bacteria and/or archaea, and subsequently to nitrate by nitrite oxidizing bacteria (NOB). Recent studies in NOB metabolism, however, have revealed that certain......, with nitrite as the main energy source. Community assembly was monitored on well-established biofilms formed on the grains of rapid sand filter (RSF) for drinking water production. RSF sand was placed in laboratory scale column bioreactors and subjected to continuous feeding of tap water spiked with NO2- (1 mg...... sequences (100% similarity to uncultured Nitrospira sp. clone KC836101 (Pester et al., 2014)). These observations indicate different behavior of Nitrospira in the absence of ammonia and point to a possible competitive advantage of canonical Nitrospira in environments where nitrite is the sole nitrogen...

  19. Savannah River Site Tank Cleaning: Corrosion Rate For One Versus Eight Percent Oxalic Acid Solution

    International Nuclear Information System (INIS)

    Ketusky, E.; Subramanian, K.

    2011-01-01

    Until recently, the use of oxalic acid for chemically cleaning the Savannah River Site (SRS) radioactive waste tanks focused on using concentrated 4 and 8-wt% solutions. Recent testing and research on applicable dissolution mechanisms have concluded that under appropriate conditions, dilute solutions of oxalic acid (i.e., 1-wt%) may be more effective. Based on the need to maximize cleaning effectiveness, coupled with the need to minimize downstream impacts, SRS is now developing plans for using a 1-wt% oxalic acid solution. A technology gap associated with using a 1-wt% oxalic acid solution was a dearth of suitable corrosion data. Assuming oxalic acid's passivation of carbon steel was proportional to the free oxalate concentration, the general corrosion rate (CR) from a 1-wt% solution may not be bound by those from 8-wt%. Therefore, after developing the test strategy and plan, the corrosion testing was performed. Starting with the envisioned process specific baseline solvent, a 1-wt% oxalic acid solution, with sludge (limited to Purex type sludge-simulant for this initial effort) at 75 C and agitated, the corrosion rate (CR) was determined from the measured weight loss of the exposed coupon. Environmental variations tested were: (a) Inclusion of sludge in the test vessel or assuming a pure oxalic acid solution; (b) acid solution temperature maintained at 75 or 45 C; and (c) agitation of the acid solution or stagnant. Application of select electrochemical testing (EC) explored the impact of each variation on the passivation mechanisms and confirmed the CR. The 1-wt% results were then compared to those from the 8-wt%. The immersion coupons showed that the maximum time averaged CR for a 1-wt% solution with sludge was less than 25-mils/yr for all conditions. For an agitated 8-wt% solution with sludge, the maximum time averaged CR was about 30-mils/yr at 50 C, and 86-mils/yr at 75 C. Both the 1-wt% and the 8-wt% testing demonstrated that if the sludge was removed from

  20. Charge dynamics in conducting polyaniline–metal oxalate composites

    Indian Academy of Sciences (India)

    Unknown

    Polyaniline; metal oxalate composites; charge transport; mobile and fixed spins; VRH conduc- tion mechanism ... Al, Mn and Co on doping into Pani improve the poly- merization ... dopants on charge dynamics with EPR and other tech- niques.

  1. Low nitrous oxide production through nitrifier-denitrification in intermittent-feed high-rate nitritation reactors

    DEFF Research Database (Denmark)

    Su, Qingxian; Ma, Chun; Domingo-Felez, Carlos

    2017-01-01

    Nitrous oxide (N2O) production from autotrophic nitrogen conversion processes, especially nitritation systems, can be significant, requires understanding and calls for mitigation. In this study, the rates and pathways of N2O production were quantified in two lab-scale sequencing batch reactors...... to maintain high nitritation efficiency and high nitritation rates at 20-26 °C over a period of ∼300 days. Even at the high nitritation efficiencies, net N2O production was low (∼2% of the oxidized ammonium). Net N2O production rates transiently increased with a rise in pH after each feeding, suggesting...... operated with intermittent feeding and demonstrating long-term and high-rate nitritation. The resulting reactor biomass was highly enriched in ammonia-oxidizing bacteria, and converted ∼93 ± 14% of the oxidized ammonium to nitrite. The low DO set-point combined with intermittent feeding was sufficient...

  2. Organic oxalate as leachant and precipitant for the recovery of valuable metals from spent lithium-ion batteries

    International Nuclear Information System (INIS)

    Sun Liang; Qiu Keqiang

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► Vacuum pyrolysis as a pretreatment was used to separate cathode material from aluminum foils. ► Cobalt and lithium can be leached using oxalate while cobalt can be directly precipitated as cobalt oxalate. ► Cobalt and lithium can be separated efficiently from each other only in the oxalate leaching process. ► High reaction efficiency of LiCoO 2 was obtained with oxalate. - Abstract: Spent lithium-ion batteries containing lots of strategic resources such as cobalt and lithium are considered as an attractive secondary resource. In this work, an environmentally compatible process based on vacuum pyrolysis, oxalate leaching and precipitation is applied to recover cobalt and lithium from spent lithium-ion batteries. Oxalate is introduced as leaching reagent meanwhile as precipitant which leaches and precipitates cobalt from LiCoO 2 and CoO directly as CoC 2 O 4 ·2H 2 O with 1.0 M oxalate solution at 80 °C and solid/liquid ratio of 50 g L −1 for 120 min. The reaction efficiency of more than 98% of LiCoO 2 can be achieved and cobalt and lithium can also be separated efficiently during the hydrometallurgical process. The combined process is simple and adequate for the recovery of valuable metals from spent lithium-ion batteries.

  3. Substituting milk for apple juice does not increase kidney stone risk in most normocalciuric adults who form calcium oxalate stones.

    Science.gov (United States)

    Massey, L K; Kynast-Gales, S A

    1998-03-01

    Increasing intake of dietary calcium from less than 400 mg to 800 mg daily may decrease the absorption of dietary oxalate, which in turn would decrease urinary oxalate excretion. The effect of substituting milk for apple juice on urine composition and risk of calcium oxalate precipitability was studied. Twenty-one normocalciuric adults with a history of at least 1 calcium oxalate stone and urinary oxalate excretion exceeding 275 micromol/day on their self-selected diet. Randomized crossover trial. Each participant consumed two moderate-oxalate (2,011 micromol/day) study diets, which were identical except that one contained 360 mL milk and the other contained 540 mL apple juice as the beverage with meals. Four days free-living then 2 days in the metabolic unit of a university nutrition department. Tiselius risk index for calcium oxalate precipitability calculated from urine composition. Paired t tests. Twenty-four hour urinary oxalate excretion was 18% lower (Pjuice diet: 423 vs 514 micromol, respectively. Calcium excretion was 17% higher (Pjuice diet: 4.7 vs 3.9 mmol, respectively. Urinary magnesium and citrate excretion, volume, and Tiselius risk index did not differ between diets. Substituting 360 mL milk daily for apple juice with meals in a diet containing moderate amounts of dietary oxalate from whole grains, legumes, fruits, and vegetables does not increase the risk index of calcium oxalate precipitability in most normocalciuric adults who form stones.

  4. Dissolution of Simulated and Radioactive Savannah River Site High-Level Waste Sludges with Oxalic Acid & Citric Acid Solutions

    International Nuclear Information System (INIS)

    STALLINGS, MARY

    2004-01-01

    This report presents findings from tests investigating the dissolution of simulated and radioactive Savannah River Site sludges with 4 per cent oxalic acid and mixtures of oxalic and citric acid previously recommended by a Russian team from the Khlopin Radium Institute and the Mining and Chemical Combine (MCC). Testing also included characterization of the simulated and radioactive waste sludges. Testing results showed the following: Dissolution of simulated HM and PUREX sludges with oxalic and citric acid mixtures at SRTC confirmed general trends reported previously by Russian testing. Unlike the previous Russian testing six sequential contacts of a mixture of oxalic acid citric acids at a 2:1 ratio (v/w) of acid to sludge did not produce complete dissolution of simulated HM and PUREX sludges. We observed that increased sludge dissolution occurred at a higher acid to sludge ratio, 50:1 (v/w), compared to the recommended ratio of 2:1 (v/w). We observed much lower dissolution of aluminum in a simulated HM sludge by sodium hydroxide leaching. We attribute the low aluminum dissolution in caustic to the high fraction of boehmite present in the simulated sludge. Dissolution of HLW sludges with 4 per cent oxalic acid and oxalic/citric acid followed general trends observed with simulated sludges. The limited testing suggests that a mixture of oxalic and citric acids is more efficient for dissolving HM and PUREX sludges and provides a more homogeneous dissolution of HM sludge than oxalic acid alone. Dissolution of HLW sludges in oxalic and oxalic/citric acid mixtures produced residual sludge solids that measured at higher neutron poison to equivalent 235U weight ratios than that in the untreated sludge solids. This finding suggests that residual solids do not present an increased nuclear criticality safety risk. Generally the neutron poison to equivalent 235U weight ratios of the acid solutions containing dissolved sludge components are lower than those in the untreated

  5. Determining the biochemical properties of the Oxalate Biosynthetic Component (Obc)1 from Burkholderia mallei

    Science.gov (United States)

    Oxalic acid is produced by a variety of organisms ranging from simple microbes to complex animals. This acid has been proposed to fulfill various physiological and pathological functions which vary between organisms. In bacteria from the Burkholderia genus, oxalate secretion has been shown to be quo...

  6. Evaluation of soluble oxalates content in infusions of different kinds of tea and coffee available on the Polish market.

    Science.gov (United States)

    Rusinek, Elzbieta

    2012-01-01

    Tea and coffee are the potentially rich source of oxalic acid, which can act as a antinutrient. The aim of this study was to determine and evaluate the content of soluble oxalates in teas and coffees available on the Polish market. The green, red and black teas, and black natural ground and instant coffees were used for preparing the infusions. The manganometric method was used for the determination of the oxalates in the infusions. The mean oxalates content in the infusions from 3 g of black teas was 115.68 mg/100 cm3 and was higher as compared to red teas (101.91 mg/100 cm3) and green teas (87.64 mg/100 cm3). Disregarding the variety of analyzed teas, the largest oxalates content was in infusions of pure one-component tea--"Sir Roger" (164.82-174.22 mg/100 cm3), while the lowest oxalates content was noted in the tea containing the components from other plants ("Bio-Active" with grapefruit juice--reaching as low level as 39.00 mg/100 cm3). Instant coffees contained larger amount of oxalates than natural ground coffees. Irrespective of the kind of the tested coffees, the lowest oxalates content was found in the infusions from the following coffees: Tchibo Exclusive--19.62 mg/100 cm3, Gala ulubiona--37.32 mg/100 cm3, and Maxwell House--38.40 mg/100 cm3, while the highest oxalates content in instant coffee--Nescafe Espiro 51.80 mg/100 cm3. The results revealed a significant relation between phytochemical composition of analyzed teas and coffees and the level of soluble oxalates in infusions prepared from the tested products.

  7. Arabidopsis Root-Type Ferredoxin:NADP(H) Oxidoreductase 2 is Involved in Detoxification of Nitrite in Roots.

    Science.gov (United States)

    Hachiya, Takushi; Ueda, Nanae; Kitagawa, Munenori; Hanke, Guy; Suzuki, Akira; Hase, Toshiharu; Sakakibara, Hitoshi

    2016-11-01

    Ferredoxin:NADP(H) oxidoreductase (FNR) plays a key role in redox metabolism in plastids. Whereas leaf FNR (LFNR) is required for photosynthesis, root FNR (RFNR) is believed to provide electrons to ferredoxin (Fd)-dependent enzymes, including nitrite reductase (NiR) and Fd-glutamine-oxoglutarate aminotransferase (Fd-GOGAT) in non-photosynthetic conditions. In some herbal species, however, most nitrate reductase activity is located in photosynthetic organs, and ammonium in roots is assimilated mainly by Fd-independent NADH-GOGAT. Therefore, RFNR might have a limited impact on N assimilation in roots grown with nitrate or ammonium nitrogen sources. AtRFNR genes are rapidly induced by application of toxic nitrite. Thus, we tested the hypothesis that RFNR could contribute to nitrite reduction in roots by comparing Arabidopsis thaliana seedlings of the wild type with loss-of-function mutants of RFNR2 When these seedlings were grown under nitrate, nitrite or ammonium, only nitrite nutrition caused impaired growth and nitrite accumulation in roots of rfnr2 Supplementation of nitrite with nitrate or ammonium as N sources did not restore the root growth in rfnr2 Also, a scavenger for nitric oxide (NO) could not effectively rescue the growth impairment. Thus, nitrite toxicity, rather than N depletion or nitrite-dependent NO production, probably causes the rfnr2 root growth defect. Our results strongly suggest that RFNR2 has a major role in reduction of toxic nitrite in roots. A specific set of genes related to nitrite reduction and the supply of reducing power responded to nitrite concomitantly, suggesting that the products of these genes act co-operatively with RFNR2 to reduce nitrite in roots. © 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.

  8. Studies on Pu(IV)/(III)-oxalate precipitation from nitric acid containing high concentration of calcium and fluoride ions

    International Nuclear Information System (INIS)

    Kalsi, P.K.; Pawar, S.M.; Ghadse, D.R.; Joshi, A.R.; Ramakrishna, V.V.; Vaidya, V.N.; Venugopal, V.

    2003-01-01

    Plutonium (IV)/(III) oxalate precipitation from nitric acid solution, containing large amount of calcium and fluoride ions was investigated. It was observed that direct precipitation of Pu (IV) oxalate from nitric acid containing large amount of calcium and fluoride ions did not give good decontamination of Pu from calcium and fluoride impurities. However, incorporation of hydroxide precipitation using ammonium hydroxide prior to Pu (IV) oxalate precipitation results into PuO 2 with much less calcium and fluoride impurities. Whereas, good decontamination from calcium and fluoride impurities could be obtained by employing Pu (III) oxalate precipitation directly from nitric acid containing large amount of calcium and fluoride ions. A method was also developed to recover Pu from the oxalate waste containing calcium and fluoride ions. (author)

  9. A kinetic and ESR investigation of iron(II) oxalate oxidation by hydrogen peroxide and dioxygen as a source of hydroxyl radicals

    DEFF Research Database (Denmark)

    Park, J S; Wood, P M; Davies, Michael Jonathan

    1997-01-01

    The reaction of Fe(II) oxalate with hydrogen peroxide and dioxygen was studied for oxalate concentrations up to 20 mM and pH 2-5, under which conditions mono- and bis-oxalate complexes (Fe[II](ox) and Fe[II](ox)2[2-]) and uncomplexed Fe2+ must be considered. The reaction of Fe(II) oxalate...... with hydrogen peroxide (Fe2+ + H2O2 --> Fe3+ + .OH + OH-) was monitored in continuous flow by ESR with t-butanol as a radical trap. The reaction is much faster than for uncomplexed Fe2+ and a rate constant, k = 1 x 10(4) M(-1) s(-1) is deduced for Fe(II)(ox). The reaction of Fe(II) oxalate with dioxygen...... by oxalate. Further ESR studies with DMPO as spin trap reveal that reaction of Fe(II) oxalate with hydrogen peroxide can also lead to formation of the carboxylate radical anion (CO2-), an assignment confirmed by photolysis of Fe(II) oxalate in the presence of DMPO....

  10. Electrochemical Biosensor for Nitrite Based on Polyacrylic-Graphene Composite Film with Covalently Immobilized Hemoglobin

    Directory of Open Access Journals (Sweden)

    Raja Zaidatul Akhmar Raja Jamaluddin

    2018-04-01

    Full Text Available A new biosensor for the analysis of nitrite in food was developed based on hemoglobin (Hb covalently immobilized on the succinimide functionalized poly(n-butyl acrylate-graphene [poly(nBA-rGO] composite film deposited on a carbon-paste screen-printed electrode (SPE. The immobilized Hb on the poly(nBA-rGO conducting matrix exhibited electrocatalytic ability for the reduction of nitrite with significant enhancement in the reduction peak at −0.6 V versus Ag/AgCl reference electrode. Thus, direct determination of nitrite can be achieved by monitoring the cathodic peak current signal of the proposed polyacrylic-graphene hybrid film-based voltammetric nitrite biosensor. The nitrite biosensor exhibited a reproducible dynamic linear response range from 0.05–5 mg L−1 nitrite and a detection limit of 0.03 mg L−1. No significant interference was observed by potential interfering ions such as Ca2+, Na+, K+, NH4+, Mg2+, and NO3− ions. Analysis of nitrite in both raw and processed edible bird’s nest (EBN samples demonstrated recovery of close to 100%. The covalent immobilization of Hb on poly(nBA-rGO composite film has improved the performance of the electrochemical nitrite biosensor in terms of broader detection range, lower detection limit, and prolonged biosensor stability.

  11. Nitrogen-Doped Carbon Quantum Dots as Fluorescent Probes for Sensitive and Selective Detection of Nitrite

    Directory of Open Access Journals (Sweden)

    Zhibiao Feng

    2017-11-01

    Full Text Available Nitrites are the upstream precursors of the carcinogenic nitrosamines, which are widely found in the natural environment and many food products. It is important to develop a simple and sensitive sensor for detecting nitrites. In this work, a fluorescence probe based on nitrogen-doped carbon quantum dots (N-CQDs was developed for the sensitive and selective determination of nitrites. At pH 2, the fluorescence of N-CQDs can be selectively quenched by nitrite due to the fact N-nitroso compounds can be formed in the reaction of amide groups with nitrous acid, which results in fluorescence static quenching. Under optimal conditions, fluorescence intensity quenching upon addition of nitrite gives a satisfactory linear relationship covering the linear range of 0.2–20 μM, and the limit of detection (LOD is 40 nM. Moreover, this method has been successfully applied to the determination of nitrites in tap water, which indicates its great potential for monitoring of nitrites in environmental samples.

  12. The effect of environmental hypercapnia and size on nitrite toxicity in the striped catfish (Pangasianodon hypophthalmus)

    DEFF Research Database (Denmark)

    Hvas, Malthe; Damsgaard, Christian; Gam, Le Thi Hong

    2016-01-01

    Striped catfish (Pangasianodon hypophthalmus) are farmed intensively at high stocking densities in Vietnam where they are likely to encounter environmental hypercapnia as well as occasional high levels of aquatic nitrite. Nitrite competes with Cl- for uptake at the branchial HCO3-/Cl- exchanger, ...... the ambient concentration, while small fish did not. Small P. hypophthalmus instead had significantly higher plasma [nitrate], and haemoglobin concentrations, revealing greater capacity for detoxifying nitrite by oxidising it to nitrate.......Striped catfish (Pangasianodon hypophthalmus) are farmed intensively at high stocking densities in Vietnam where they are likely to encounter environmental hypercapnia as well as occasional high levels of aquatic nitrite. Nitrite competes with Cl- for uptake at the branchial HCO3-/Cl- exchanger...... to a reduced nitrite uptake. To assess the effect of hypercapnia on nitrite uptake, fish were cannulated in the dorsal aorta, allowing repeated blood sampling for measurements of haemoglobin derivatives, plasma ions and acid-base status during exposure to 0.9 mM nitrite alone and in combination with acute...

  13. Effect of luminal or circulating nitrite on colonic ion movement in the rat

    International Nuclear Information System (INIS)

    Radcliffe, B.C.; Nance, S.H.; Deakin, E.J.; Roediger, W.E.W.

    1987-01-01

    The disposition of intravenously or luminally administered nitrite across the colonic mucosa and its effect on ion movement into or from the colon was assessed in anesthetized Porton rats using the isolated colon instilled either with sodium chloride or sodium chloride with sodium butyrate. Ionic changes in the colon after intravenous injection of 10 μmol NaNO 2 were compared with those occurring after injection of 10 μmol NaCl. After intravenous administration of nitrite, both nitrite and nitrate appeared in the colonic instillate in a ratio of 1:1. Nitrite increased chloride absorption (110%) and bicarbonate production (20%) when 40 mM butyrate was included in the instillate. Net sodium absorption, measured in the whole colon, was unchanged. Intravenous nitrite had no effect on ionic movement in the absence of butyrate. When NaNO 2 was included luminally with the sodium chloride-butyrate instillate, bicarbonate production rate increased, but sodium and chloride absorption were unaffected. Nitrite concentration in the instillate decreased during the 40-min experimental period at a rate of 0.275 nmol·min -1 ·cm -2 and nitrate appeared at a rate of 0.037 nmol·min -1 ·cm -2 . The authors conclude that nitrite stimulates bicarbonate production in the colon, probably by stimulating the oxidation by butyrate, the main source of CO 2 generation by the colonic mucosa

  14. Fungi, bacteria and soil pH: the oxalate-carbonate pathway as a model for metabolic interaction.

    Science.gov (United States)

    Martin, Gaëtan; Guggiari, Matteo; Bravo, Daniel; Zopfi, Jakob; Cailleau, Guillaume; Aragno, Michel; Job, Daniel; Verrecchia, Eric; Junier, Pilar

    2012-11-01

    The oxalate-carbonate pathway involves the oxidation of calcium oxalate to low-magnesium calcite and represents a potential long-term terrestrial sink for atmospheric CO(2). In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria, fungi and calcium oxalate amendments was studied using microcosms. In a model system with sterile soil amended with laboratory cultures of oxalotrophic bacteria and fungi, the addition of calcium oxalate induced a distinct pH shift and led to the final precipitation of calcite. However, the simultaneous presence of bacteria and fungi was essential to drive this pH shift. Growth of both oxalotrophic bacteria and fungi was confirmed by qPCR on the frc (oxalotrophic bacteria) and 16S rRNA genes, and the quantification of ergosterol (active fungal biomass) respectively. The experiment was replicated in microcosms with non-sterilized soil. In this case, the bacterial and fungal contribution to oxalate degradation was evaluated by treatments with specific biocides (cycloheximide and bronopol). Results showed that the autochthonous microflora oxidized calcium oxalate and induced a significant soil alkalinization. Moreover, data confirmed the results from the model soil showing that bacteria are essentially responsible for the pH shift, but require the presence of fungi for their oxalotrophic activity. The combined results highlight that the interaction between bacteria and fungi is essential to drive metabolic processes in complex environments such as soil. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  15. Effect of Ethanolamines on Corrosion Inhibition of Ductile Cast Iron in Nitrite Containing Solutions

    International Nuclear Information System (INIS)

    Kim, K. T.; Kim, Y. S.; Chang, H. Y.; Lim, B. T.; Park, H. B.

    2016-01-01

    In this work, synergistic corrosion inhibition effect of nitrite and 3 kinds of ethanolamines on ductile cast iron using chemical and electrochemical methods was evaluated. This work attempts to clarify the synergistic effect of nitrite and ethanolamines. The effects of single addition of TEA, DEA, and MEA, and mixed addition of nitrite plus TEA, DEA or MEA on the corrosion inhibition of ductile cast iron in a tap water were evaluated. A huge amount of single addition of ethanolamine was needed. However, the synergistic effect by mixed addition was observed regardless of the combination of nitrite and triethanolamines, but their effects increased in a series of MEA + nitrite > DEA + nitrite > TEA + nitrite. This tendency of synergistic effect was attributed to the film properties and polar effect; TEA addition couldn't form the film showing high film resistance and semiconductive properties, but DEA or MEA could build the film having relatively high film resistance and n-type semiconductive properties. Moreover, it can be explained that this behaviour was closely related to electron attractive group within the ethanolamines, and thus corrosion inhibition power depends upon the number of the electron attractive group of MEA, DEA, and TEA.

  16. Effect of Ethanolamines on Corrosion Inhibition of Ductile Cast Iron in Nitrite Containing Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. T.; Kim, Y. S. [Andong National University, Andong (Korea, Republic of); Chang, H. Y.; Lim, B. T.; Park, H. B. [KEPCO Engineering and Construction Company, Gimcheon (Korea, Republic of)

    2016-08-15

    In this work, synergistic corrosion inhibition effect of nitrite and 3 kinds of ethanolamines on ductile cast iron using chemical and electrochemical methods was evaluated. This work attempts to clarify the synergistic effect of nitrite and ethanolamines. The effects of single addition of TEA, DEA, and MEA, and mixed addition of nitrite plus TEA, DEA or MEA on the corrosion inhibition of ductile cast iron in a tap water were evaluated. A huge amount of single addition of ethanolamine was needed. However, the synergistic effect by mixed addition was observed regardless of the combination of nitrite and triethanolamines, but their effects increased in a series of MEA + nitrite > DEA + nitrite > TEA + nitrite. This tendency of synergistic effect was attributed to the film properties and polar effect; TEA addition couldn't form the film showing high film resistance and semiconductive properties, but DEA or MEA could build the film having relatively high film resistance and n-type semiconductive properties. Moreover, it can be explained that this behaviour was closely related to electron attractive group within the ethanolamines, and thus corrosion inhibition power depends upon the number of the electron attractive group of MEA, DEA, and TEA.

  17. The kinetics for ammonium and nitrite oxidation under the effect of hydroxylamine.

    Science.gov (United States)

    Wan, Xinyu; Xiao, Pengying; Zhang, Daijun; Lu, Peili; Yao, Zongbao; He, Qiang

    2016-01-01

    The kinetics for ammonium (NH4(+)) oxidation and nitrite (NO2(-)) oxidation under the effect of hydroxylamine (NH2OH) were studied by respirometry using the nitrifying sludge from a laboratory-scale sequencing batch reactor. Modified models were used to estimate kinetics parameters of ammonia and nitrite oxidation under the effect of hydroxylamine. An inhibition effect of hydroxylamine on the ammonia oxidation was observed under different hydroxylamine concentration levels. The self-inhibition coefficient of hydroxylamine oxidation and noncompetitive inhibition coefficient of hydroxylamine for nitrite oxidation was estimated by simulating exogenous oxygen-uptake rate profiles, respectively. The inhibitive effect of NH2OH on nitrite-oxidizing bacteria was stronger than on ammonia-oxidizing bacteria. This work could provide fundamental data for the kinetic investigation of the nitrification process.

  18. Amperometric detection of nitrite based on Dawson-type vanodotungstophosphate and carbon nanotubes

    International Nuclear Information System (INIS)

    Zhang, Di; Ma, Huiyuan; Chen, Yanyan; Pang, Haijun; Yu, Yan

    2013-01-01

    Graphical abstract: A composite film has been constructed by vanodotungstophosphate α 2 -K 7 P 2 VW 17 O 62 ·18H 2 O (P 2 W 17 V) and carbon nanotubes (CNTs) using the layer-by-layer self-assembly method. The incorporation of CNTs and P 2 W 17 V into the composite film endowed the modified electrode fast electron transfer rate and high electrocatalytic activity of toward nitrite oxidation. This nitrite sensor shows broad linear range, low detection limit, and high sensitivity and stability. Also it did not show any interference with other potential interfering species, and was successfully employed for determination of nitrite in real samples. -- Highlights: •A composite film was constructed by a vanodotungstophosphate and carbon nanotubes. •The composite film showed fast electron transfer rate and high electrocatalytic activity of toward nitrite oxidation. •The proposed sensor can amperometricially detect nitrite with high sensitivity and selectivity. -- Abstract: A nitrite sensor based on Dawson vanodotungstophosphates α 2 -K 7 P 2 VW 17 O 62 ·18H 2 O (P 2 W 17 V) and carbon nanotubes (CNTs) was prepared by electrostatic layer-by-layer self-assembly technique. The sensor {PEI/PSS/[PDDA/P 2 W 17 V-CNTs] n } was characterized by UV–vis spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectra (XPS). The electron transfer and sensing ability of this sensor were explored using cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) technology. The results show that the incorporation of CNTs and P 2 W 17 V into the composite film endowed the modified electrode with fast transfer rate and high electrocatalytic activity towards oxidation of nitrite. This nitrite sensor with 10 bilayers has a broad linear range of 5 × 10 −8 to 2.13 × 10 −3 M, a low detection limit of 0.0367 μM (S N −1 = 3), a high sensitivity of 0.35 mA mM −1 NO 2 − , an excellent anti-interference property in the

  19. Determination of water-soluble forms of oxalic and formic acids in soils by ion chromatography

    Science.gov (United States)

    Karicheva, E.; Guseva, N.; Kambalina, M.

    2016-03-01

    Carboxylic acids (CA) play an important role in the chemical composition origin of soils and migration of elements. The content of these acids and their salts is one of the important characteristics for agrochemical, ecological, ameliorative and hygienic assessment of soils. The aim of the article is to determine water-soluble forms of same carboxylic acids — (oxalic and formic acids) in soils by ion chromatography with gradient elution. For the separation and determination of water-soluble carboxylic acids we used reagent-free gradient elution ion-exchange chromatography ICS-2000 (Dionex, USA), the model solutions of oxalate and formate ions, and leachates from soils of the Kola Peninsula. The optimal gradient program was established for separation and detection of oxalate and formate ions in water solutions by ion chromatography. A stability indicating method was developed for the simultaneous determination of water-soluble organic acids in soils. The method has shown high detection limits such as 0.03 mg/L for oxalate ion and 0.02 mg/L for formate ion. High signal reproducibility was achieved in wide range of intensities which correspond to the following ion concentrations: from 0.04 mg/g to 10 mg/L (formate), from 0.1 mg/g to 25 mg/L (oxalate). The concentration of formate and oxalate ions in soil samples is from 0.04 to 0.9 mg/L and 0.45 to 17 mg/L respectively.

  20. Diminution of oxalate induced renal tubular epithelial cell injury and inhibition of calcium oxalate crystallization in vitro by aqueous extract of Tribulus terrestris

    Directory of Open Access Journals (Sweden)

    A. Aggarwal

    2010-08-01

    Full Text Available PURPOSE: Recurrence and persistent side effects of present day treatment for urolithiasis restrict their use, so an alternate solution, using phytotherapy is being sought. The present study attempted to evaluate the antilithiatic properties of Tribulus terrestris commonly called as “gokhru” which is often used in ayurveda to treat various urinary diseases including urolithiasis. MATERIALS AND METHODS: The activity of Tribulus terrestris was investigated on nucleation and the growth of the calcium oxalate (CaOx crystals as well as on oxalate induced cell injury of NRK 52E renal epithelial cells. RESULTS: Tribulus terrestris extract exhibited a concentration dependent inhibition of nucleation and the growth of CaOx crystals. When NRK-52E cells were injured by exposure to oxalate for 72 h, Tribulus terrestris extract prevented the injury in a dose-dependent manner. On treatment with the different concentrations of the plant, the cell viability increased and lactate dehydrogenase release decreased in a concentration dependent manner. CONCLUSION: The current data suggests that Tribulus terrestris extract not only has a potential to inhibit nucleation and the growth of the CaOx crystals but also has a cytoprotective role. Our results indicate that it could be a potential candidate for phytotherapy against urolithiasis.

  1. Circular patterns of calcium oxalate monohydrate induced by defective Langmuir-Blodgett film on quartz substrates

    Energy Technology Data Exchange (ETDEWEB)

    He Jieyu [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Ouyang Jianming [Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China)], E-mail: toyjm@jnu.edu.cn

    2009-01-01

    The defective Langmuir-Blodgett (LB) film of dipalmitoylphosphatidylcholine (DPPC) on quartz injured by potassium oxalate (K{sub 2}C{sub 2}O{sub 4}) was used as a model system to induce growth of calcium oxalate crystals. Atomic force microscopy (AFM) indicated that circular defective domains with a diameter of 1-200 {mu}m existed in the LB film. Scanning electron microscopy (SEM) showed circular patterns of aggregated calcium oxalate monohydrate (COM) crystallites were induced by these defective domains. It was ascribed to that the interaction between the negatively-charged oxalate ions and the phosphatidyl groups in DPPC headgroups makes the phospholipid molecules rearranged and exist in an out-of-order state in the LB film, especially at the boundaries of liquid-condensed (LC)/liquid-expanded (LE) phases, which provide much more nucleating sites for COM crystals.

  2. Can urinary nitrite results be used to conduct antimicrobial option for urinary tract infection in children?

    Science.gov (United States)

    Mahyar, Abolfazl; Ayazi, Parviz; Froozesh, Mahta; Daneshi-Kohan, Mohammad-Mahdi; Barikani, Ameneh

    2012-06-01

    This study was performed to determine the relationship between urinary nitrite results and bacterial resistance to antimicrobial drugs in urinary tract infection of children. In a cross-section study 119 children younger than 12 years with urinary tract infection were evaluated in Qazvin children's hospital. Patients were divided into negative and positive nitrite groups depending on urinary nitrite test result. Rates of antibiotic resistance in the two groups were compared. Sixty seven patients were in the negative nitrite group and 52 in the positive nitrite group. Resistance rates to ceftriaxone, trimethoprim sulfamethoxazole, ampicillin, gentamicin, amikacin, nalidixic acid, cephalothin and nitrofurantoin in the nitrite negative group were 7.5%, 31.3%, 50.7%, 11.9%, 9%, 3%, 14.9% and 11.9%, respectively. These values in the nitrite positive group were 21.2%, 28.8%, 63.5%, 7.7%, 5.8%, 1.9%, 9.6%, and 3.8%, respectively (P>0.05). This study showed that there is no correlation between urinary nitrite results and bacterial resistance to antimicrobial drugs. Therefore, it seems that physicians should not adjust antibiotic therapy for UTI based on nitrite results.

  3. Effects of dietary interventions on 24-hour urine parameters in patients with idiopathic recurrent calcium oxalate stones

    Directory of Open Access Journals (Sweden)

    Mustafa Kıraç

    2013-02-01

    Full Text Available The aim of this study is to investigate the effects of dietary factors on 24-hour urine parameters in patients with idiopathic recurrent calcium oxalate stones. A total of 108 of idiopathic recurrent calcium oxalate stones were included in the study. A 24-hour urinalysis was performed and metabolic abnormalities were measured for all of the patients. All of the patients were given specialized diets for their 24-hour urine abnormalities. At the end of first month, the same parameters were examined in another 24-hour urinalysis. Hyperoxaluria, hypernatruria, and hypercalciuria were found in 84 (77%, 43 (39.8%, and 38 (35.5% of the patients, respectively. The differences between the oxalate, sodium, volume, uric acid, and citrate parameters before and after the dietary intervention were significant (p < 0.05. The calcium parameters were not significantly different before and after the intervention. We found that oxalate, sodium, volume, uric acid, and citrate—but not calcium—abnormalities in patients with recurrent calcium oxalate stones can be corrected by diet. The metabolic profiles of idiopathic calcium oxalate stone patients should be evaluated and the appropriate dietary interventions should be implemented to decrease stone recurrence.

  4. Nitrite-Mediated Hypoxic Vasodilation Predicted from Mathematical Modeling and Quantified from in Vivo Studies in Rat Mesentery

    Directory of Open Access Journals (Sweden)

    Donald G. Buerk

    2017-12-01

    Full Text Available Nitric oxide (NO generated from nitrite through nitrite reductase activity in red blood cells has been proposed to play a major role in hypoxic vasodilation. However, we have previously predicted from mathematical modeling that much more NO can be derived from tissue nitrite reductase activity than from red blood cell nitrite reductase activity. Evidence in the literature suggests that tissue nitrite reductase activity is associated with xanthine oxidoreductase (XOR and/or aldehyde oxidoreductase (AOR. We investigated the role of XOR and AOR in nitrite-mediated vasodilation from computer simulations and from in vivo exteriorized rat mesentery experiments. Vasodilation responses to nitrite in the superfusion medium bathing the mesentery equilibrated with 5% O2 (normoxia or zero O2 (hypoxia at either normal or acidic pH were quantified. Experiments were also conducted following intraperitoneal (IP injection of nitrite before and after inhibiting XOR with allopurinol or inhibiting AOR with raloxifene. Computer simulations for NO and O2 transport using reaction parameters reported in the literature were also conducted to predict nitrite-dependent NO production from XOR and AOR activity as a function of nitrite concentration, PO2 and pH. Experimentally, the largest arteriolar responses were found with nitrite >10 mM in the superfusate, but no statistically significant differences were found with hypoxic and acidic conditions in the superfusate. Nitrite-mediated vasodilation with IP nitrite injections was reduced or abolished after inhibiting XOR with allopurinol (p < 0.001. Responses to IP nitrite before and after inhibiting AOR with raloxifene were not as consistent. Our mathematical model predicts that under certain conditions, XOR and AOR nitrite reductase activity in tissue can significantly elevate smooth muscle cell NO and can serve as a compensatory pathway when endothelial NO production is limited by hypoxic conditions. Our theoretical and

  5. The redox interplay between nitrite and nitric oxide: From the gut to the brain

    Directory of Open Access Journals (Sweden)

    Cassilda Pereira

    2013-01-01

    We here discuss the implications of the redox conversion of nitrite to ·NO in the gut, how nitrite-derived ·NO may signal from the digestive to the central nervous system, influencing brain function, as well as a putative ascorbate-driven nitrite/NO pathway occurring in the brain.

  6. Electrocatalytic reduction of nitrite using ferricyanide; Application for its simple and selective determination

    International Nuclear Information System (INIS)

    Ojani, Reza; Raoof, Jahan-Bakhsh; Zarei, Ebrahim

    2006-01-01

    The electrocatalytic reduction of nitrite has been studied by ferricyanide at the surface of carbon paste electrode. Cyclic voltammetry and chronoamperometry techniques were used to investigate the suitability of ferricyanide as a mediator for the electrocatalytic nitrite reduction in aqueous solution with various pH. Results showed that pH 0.00 is the most suitable for this purpose. In the optimum pH, the electrocatalytic ability about 700 mV can be seen and the homogeneous second-order rate constant (k s ) for nitrite coupled catalytically to ferricyanide was calculated 2.75 x 10 3 M -1 s -1 by Nicholson-Shain method. Also, electron transfer coefficients (α) for ferricyanide was determined by using various electrochemical approaches such as Tafel plot in the absence and presence of nitrite 0.556 and 0.760, respectively. The catalytic reduction peak current was linearly dependent on the nitrite concentration and the linearity range obtained was 5.00 x 10 -5 to 1.00 x 10 -3 M. Detection limit has been found to be 2.63 x 10 -5 M (2σ). This method has been applied as a selective, simple and precise method for determination of nitrite in real sample

  7. Nitrite oxidizing bacteria for water treatment in coastal aquaculture system

    Science.gov (United States)

    Noorak, S.; Rakkhiaw, S.; Limjirakhajornt, K.; Uppabullung, A.; Keawtawee, T.; Sangnoi, Y.

    2018-04-01

    This research aimed to isolate and characterize nitrite oxidizing bacteria and to study their capability for water quality improvement. Fourteen strains of bacteria with nitrite-oxidizing character were isolated after 21 days of enrichment in Pep-Beef-NOB medium contained NaNO2. Two strains, SF-1 and SF-5, showed highest nitrite removal rate for 42.42% and 37.2%, respectively. These strains were determined an efficiency of open-system wastewater treatment for 14 days. The results showed that control, SF-1 and SF-5 had remove ammonia from day 1 to day 6. At the end of the study, ammonia was removed by the control, SF-1 and SF-5 for 81.27%, 70.1% and 69.82%, respectively. Nitrite concentration was lowest at day 8 with removal rate of 98.73%, 98.3% and 97.24% from control, SF-1 and SF-5, respectively. However, nitrite concentration in control experiment was increased again at day 11 whereas in SF-1 and SF-5 were increased at day 13. Chemical Oxygen Demand (COD) was decreased by 77.78%, 73.50% and 78.63% in the control, SF-1 and SF-5, respectively. Biological Oxygen Demand (BOD) in the control, SF-1 and SF-5 were reduced by 85.92%, 79.53% and 82.09%, respectively. Based on 16S rRNA gene, SF-1 and SF-5 were identified as Bacillus vietnamensis and B. firmus, respectively.

  8. Evaluation of nitrite contamination in baby foods and infant formulas marketed in Turkey.

    Science.gov (United States)

    Erkekoglu, Pinar; Baydar, Terken

    2009-05-01

    Nitrites are responsible for methemoglobinemia, to which infants younger than 6 months are thought to be the most susceptible population. This study aimed to detect whether there was any nitrite contamination in infant formulas and baby foods marketed in Turkey and to estimate possible toxicological risks in this sensitive physiological period. For this purpose, the samples were randomly collected and divided into four groups: milk-based, cereal-based, vegetable-based, and fruit-based. An easy and reliable spectrophotometric method was used by modifying the Griess method. The average nitrite contamination was found to be 204.07+/-65.80 microg/g in 42 samples, with 1,073 microg/g maximum. According to the results, baby and infant formulas include various nitrite levels; nitrite contamination might come from several sources during manufacturing, and so extreme attention must be given throughout the manufacturing process of food for infants.

  9. Properties of aqueous nitrate and nitrite from x-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jacob W.; Lam, Royce K.; Saykally, Richard J., E-mail: saykally@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Shih, Orion [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Rizzuto, Anthony M. [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Prendergast, David [The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2015-08-28

    Nitrate and nitrite ions are of considerable interest, both for their widespread use in commercial and research contexts and because of their central role in the global nitrogen cycle. The chemistry of atmospheric aerosols, wherein nitrate is abundant, has been found to depend on the interfacial behavior of ionic species. The interfacial behavior of ions is determined largely by their hydration properties; consequently, the study of the hydration and interfacial behavior of nitrate and nitrite comprises a significant field of study. In this work, we describe the study of aqueous solutions of sodium nitrate and nitrite via X-ray absorption spectroscopy (XAS), interpreted in light of first-principles density functional theory electronic structure calculations. Experimental and calculated spectra of the nitrogen K-edge XA spectra of bulk solutions exhibit a large 3.7 eV shift between the XA spectra of nitrate and nitrite resulting from greater stabilization of the nitrogen 1s energy level in nitrate. A similar shift is not observed in the oxygen K-edge XA spectra of NO{sub 3}{sup −} and NO{sub 2}{sup −}. The hydration properties of nitrate and nitrite are found to be similar, with both anions exhibiting a similar propensity towards ion pairing.

  10. Enhancing nitrite inhibition of Clostridium botulinum with isoascorbate in perishable canned cured meat.

    Science.gov (United States)

    Tompkin, R B; Christiansen, L N; Shaparis, A B

    1978-01-01

    Addition of sodium isoascorbate to the formulation for perishable canned comminuted cured meat markedly enhanced the efficacy of nitrite against Clostridium botulinum. This effect was reproducible through a series of three tests. In one test it was found that the initial addition of 50 microgram of sodium nitrite per g plus isoascorbate was as effective as 156 microgram of sodium nitrite per g alone. PMID:341810

  11. Continuous fed-batch vacuum fermentation system for glycerol from molasses by the sulfite process

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, G.P.; Naik, S.C.

    1985-01-01

    A continuous fed-batch vacuum fermentation system has been described for the production of glycerol from cane molasses (and juice) by a conventional sulfite process. A glycerol concentration of 80 g/l was achieved with a productivity of 30 g/l/day at a dilution rate of 0.4/day which is twice that from a vacuum batch process (15 g/l/day) or four times that obtained without vacuum (8 g/l/day). 8 references.

  12. Bioavailability of sodium nitrite from an aqueous solution in healthy adults.

    NARCIS (Netherlands)

    Hunault, C.C.; van Velzen, A.G.; Sips, A.J.; Schothorst, R.C.; Meulenbelt, J.|info:eu-repo/dai/nl/079479227

    2009-01-01

    Nitrate intake in humans is high through intake of vegetables such as beets, lettuce, and spinach. Nitrate itself is a compound of low toxicity but its metabolite, nitrite, formed by bacteria in the oral cavity and gastrointestinal tract, has been suspected of potential carcinogenic effects. Nitrite

  13. Removal and recovery of nitrogen and sulfur oxides from gaseous mixtures containing them

    International Nuclear Information System (INIS)

    Cooper, H.B.H.

    1984-01-01

    A cyclic process for removing lower valence nitrogen oxides from gaseous mixtures includes treating the mixtures with an aqueous media including alkali metal carbonate and alkali metal bicarbonate and a preoxygen oxidant to form higher valence nitrogen oxides and to capture these oxides as alkali metal salts, expecially nitrites and nitrates, in a carbonate/bicarbonate-containing product aqueous media. Highly selective recovery of nitrates in high purity and yield may then follow, as by crystallization, with the carbonate and bicarbonate alkali metal salts strongly increasing the selectivity and yield of nitrates. The product nitrites are converted to nitrates by oxidation after lowering the product aqueous media pH to below about 9. A cyclic process for removing sulfur oxides from gas mixtures includes treating these mixtures includes treating these mixtures with aqueous media including alkali metal carbonate and alkali metal bicarbonate where the ratio of alkali metal to sulfur dioxide is not less than 2. The sulfur values may be recovered from the resulting carbonate/bicarbonate/-sulfite containing product aqueous media as alkali metal sulfate or sulfite salts which are removed by crystallization from the carbonate-containing product aqueous media. As with the nitrates, the carbonate/bicarbonate system strongly increases yield of sulfate or sulfite during crystallization. Where the gas mixtures include both sulfur dioxide and lower valence nitrogen oxides, the processes for removing lower valence nitrogen oxides and sulfur dioxide may be combined into a single removal/recovery system, or may be effected in sequence

  14. Ammonium and nitrite oxidation at nanomolar oxygen concentrations in oxygen minimum zone waters.

    Science.gov (United States)

    Bristow, Laura A; Dalsgaard, Tage; Tiano, Laura; Mills, Daniel B; Bertagnolli, Anthony D; Wright, Jody J; Hallam, Steven J; Ulloa, Osvaldo; Canfield, Donald E; Revsbech, Niels Peter; Thamdrup, Bo

    2016-09-20

    A major percentage of fixed nitrogen (N) loss in the oceans occurs within nitrite-rich oxygen minimum zones (OMZs) via denitrification and anammox. It remains unclear to what extent ammonium and nitrite oxidation co-occur, either supplying or competing for substrates involved in nitrogen loss in the OMZ core. Assessment of the oxygen (O2) sensitivity of these processes down to the O2 concentrations present in the OMZ core (Chile at manipulated O2 levels between 5 nmol⋅L(-1) and 20 μmol⋅L(-1) Rates of both processes were detectable in the low nanomolar range (5-33 nmol⋅L(-1) O2), but demonstrated a strong dependence on O2 concentrations with apparent half-saturation constants (Kms) of 333 ± 130 nmol⋅L(-1) O2 for ammonium oxidation and 778 ± 168 nmol⋅L(-1) O2 for nitrite oxidation assuming one-component Michaelis-Menten kinetics. Nitrite oxidation rates, however, were better described with a two-component Michaelis-Menten model, indicating a high-affinity component with a Km of just a few nanomolar. As the communities of ammonium and nitrite oxidizers were similar to other OMZs, these kinetics should apply across OMZ systems. The high O2 affinities imply that ammonium and nitrite oxidation can occur within the OMZ core whenever O2 is supplied, for example, by episodic intrusions. These processes therefore compete with anammox and denitrification for ammonium and nitrite, thereby exerting an important control over nitrogen loss.

  15. A novel heterogeneous system for sulfate radical generation through sulfite activation on a CoFe{sub 2}O{sub 4} nanocatalyst surface

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zizheng [School of Civil Engineering, Wuhan University, Wuhan, 430072 (China); Yang, Shaojie; Yuan, Yanan; Xu, Jing; Zhu, Yifan [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan, 430079 (China); Li, Jinjun, E-mail: ljj0410@163.com [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan, 430079 (China); Wu, Feng, E-mail: fengwu@whu.edu.cn [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan, 430079 (China)

    2017-02-15

    Highlights: • CoFe{sub 2}O{sub 4}−S(IV)−O{sub 2} system is proposed as a new system of sulfate radical based AOPs. • Alkaline pH favors the activation of sulfite on CoFe{sub 2}O{sub 4} surface to produce oxysulfur radicals. • Generation of Co−OH complexes on the surface of CoFe{sub 2}O{sub 4} is the main factor for sulfite activation. • Degradation of organic contaminants by CoFe{sub 2}O{sub 4}−S(IV)−O{sub 2} system were achieved. • Main intermediates and pathways for the degradation of metoprolol were identified. - Abstract: Heterogeneous catalytic activation is important for potential application of new sulfate-radical-based advanced oxidation process using sulfite as source of sulfate radical. We report herein a heterogeneous system for sulfite activation by CoFe{sub 2}O{sub 4} nanocatalyst for metoprolol removal. Factors that influence metoprolol removal were investigated, including pH and initial concentrations of components. The CoFe{sub 2}O{sub 4} nanocatalyst was characterized by X-ray diffractometry (XRD) and transmission electron microscopy (TEM), and the catalytic stability was tested by consecutive runs. Radicals generated in the CoFe{sub 2}O{sub 4}−S(IV)−O{sub 2} system were identified through radical quenching experiments and by electron spin resonance (ESR). The catalytic mechanism was elucidated further by X-ray photoelectron spectroscopy (XPS). The catalytic process was dependent on initial pH, and more than 80% of the metoprolol can be removed at pH 10.0 following the Langmubir-Hinshelwood equation. The generation of Co-OH complexes on the CoFe{sub 2}O{sub 4} surface was crucial for sulfite activation. SO{sub 4}{sup ·−} was verified to be the main oxidative species responsible for metoprolol degradation. Other organic pollutants, such as sulfanilamide, sulfasalazine, 2-nitroaniline, sulfapyridine, aniline, azo dye X-3B and 4-chloroaniline, could also be removed in this CoFe{sub 2}O{sub 4}−S(IV)−O{sub 2} system. The

  16. Inactivation of Yersinia enterocolitica by nitrite and nitrate in food.

    Science.gov (United States)

    de Giusti, M; de Vito, E

    1992-01-01

    The antimicrobial effects of sodium nitrite and sodium and potassium nitrate against Yersinia enterocolitica were investigated in solution and in treated pork meat. Potassium nitrate and sodium nitrate showed only feeble antimicrobial activity in cultures; no antimicrobial activity was detected with sodium nitrite. Conversely, all three salts displayed apparent antimicrobial activity in pork meat, possibly due to selective effects on competitive flora.

  17. SAFETY EVALUATION OF OXALIC ACID WASTE RETRIEVAL IN SINGLE SHELL TANK (SST) 241-C-106

    International Nuclear Information System (INIS)

    SHULTZ, M.V.

    2003-01-01

    This report documents the safety evaluation of the process of retrieving sludge waste from single-shell tank 241-C-106 using oxalic acid. The results of the HAZOP, safety evaluation, and control allocation/decision are part of the report. This safety evaluation considers the use of oxalic acid to recover residual waste in single-shell tank (SST) 241-C-106. This is an activity not addressed in the current tank farm safety basis. This evaluation has five specific purposes: (1) Identifying the key configuration and operating assumptions needed to evaluate oxalic acid dissolution in SST 241-C-106. (2) Documenting the hazardous conditions identified during the oxalic acid dissolution hazard and operability study (HAZOP). (3) Documenting the comparison of the HAZOP results to the hazardous conditions and associated analyzed accident currently included in the safety basis, as documented in HNF-SD-WM-TI-764, Hazard Analysis Database Report. (4) Documenting the evaluation of the oxalic acid dissolution activity with respect to: (A) Accident analyses described in HNF-SD-WM-SAR-067, Tank Farms Final Safety Analysis Report (FSAR), and (B) Controls specified in HNF-SD-WM-TSR-006, Tank Farms Technical Safety Requirements (TSR). (5) Documenting the process and results of control decisions as well as the applicability of preventive and/or mitigative controls to each oxalic acid addition hazardous condition. This safety evaluation is not intended to be a request to authorize the activity. Authorization issues are addressed by the unreviewed safety question (USQ) evaluation process. This report constitutes an accident analysis

  18. Two novel metal–organic coordination polymers based on diphosphonate and oxalate: Synthesis, structures and properties

    International Nuclear Information System (INIS)

    Niu, Qing-Jun; Zheng, Yue-Qing; Zhou, Lin-Xia; Zhu, Hong-Lin

    2015-01-01

    Two 2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonato and oxalic acid bridged coordination polymers (H 2 en)[Co 3 (H 2 zdn) 2 (ox)(H 2 O) 2 ] (1) and Cd 2 (H 2 zdn)(ox) 0.5 (H 2 O) (2) (2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonic acid=H 5 zdn; oxalic acid=H 2 ox) were synthesized under hydrothermal conditions and characterized by the infrared (IR), thermogravimetric analyses (TGA), elemental analyses (EA) and X-ray diffraction (XRD). Compound 1 is bridged by phosphonate anions to 1D chain, and further linked by oxalate anions to 2D layer. Compound 2 is bridged by O–P–O units of H 5 zdn to the layer, and then pillared by oxalate anions to generate 3D frameworks. Compound 1 shows anti-ferromagnetic behaviors analyzed with the temperature-dependent zero-field ac magnetic susceptibilities, while compound 2 exhibits an influence on the luminescent property. - Graphical abstract: Linked by oxalate, two zoledronate-based metal–organic frameworks are synthesized, which exhibits the different frameworks. Magnetism and luminescent properties have been studied. The weak antiferromagnetic coupling is conducted in 1. - Highlights: • Compound 1 and 2 are first linked by oxalate anion based on zoledronic acid. • Compound 1 generates a classic “dia Diamond” (6 6 ) topology. • Compound 2 exhibits a (4 4 ·6 2 )(4 4 ·6 6 ) topology. • Magnetism and luminescent properties of 1 and 2 have been studied, respectively

  19. Reduction of nitrate and nitrite salts under hydrothermal conditions

    International Nuclear Information System (INIS)

    Foy, B.R.; Dell'Orco, P.C.; Wilmanns, E.; McInroy, R.; Ely, J.; Robinson, J.M.; Buelow, S.J.

    1994-01-01

    The feasibility of reducing nitrate/nitrite salts under hydrothermal conditions for the treatment of aqueous mixed wastes stored in the underground tanks at the Department of Energy site at Hanford, Washington was studied. The reduction of nitrate and nitrite salts by reaction with EDTA using a tank waste simulant was examined at temperatures between 623K and 800K and pressures between 0.6 and 1.2 kbar. Continuous flow reactors were used to determine kinetics and products of reactions. All reactions were studied under pressures high enough to produce single phase conditions. The reactions are rapid, go to completion in less than a minute, and produce simple products, such as carbonate, nitrogen, and nitrous oxide gases. The experimental results demonstrate the ability of chemical reactions under hydrothermal conditions to reduce the nitrate and nitrite salts and destroy organic compounds in the waste mixtures

  20. In-situ nitrite analysis in high level waste tanks

    International Nuclear Information System (INIS)

    O'Rourke, P.E.; Prather, W.S.; Livingston, R.R.

    1992-01-01

    The Savannah River Site produces special nuclear materials used in the defense of the United States. Most of the processes at SRS are primarily chemical separations and purifications. In-situ chemical analyses help improve the safety, efficiency and quality of these operations. One area where in situ fiberoptic spectroscopy can have a great impact is the management of high level radioactive waste. High level radioactive waste at SRS is stored in more than 50 large waste tanks. The waste exists as a slurry of nitrate salts and metal hydroxides at pH's higher than 10. Sodium Nitrite is added to the tanks as a corrosion inhibitor. In-situ fiberoptic probes are being developed to measure the nitrate, nitrite and hydroxide concentrations in both liquid and solid fractions. Nitrite levels can be measured between 0.01M and 1M in a 1mm pathlength optical cell

  1. Color and oxidative stability of nitrite-free cured meat after gamma irradiation

    International Nuclear Information System (INIS)

    Shahidi, F.; Pegg, R.B.; Shamsuzzaman, K.

    1991-01-01

    The effects of 5 and 10 kGy irradiation on the color and oxidative stability of meats treated with nitrite or a nitrite-free curing system were investigated. The nitrite-free curing system consisted of the preformed cooked cured-meat pigment, sodium ascorbate and sodium tripolyphosphate with or without sodium acid pyrophosphate. Irradiation had no detrimental effects on the color or flavor of either cured samples. Polyphosphates had a beneficial effect on oxidative stability but had a slight detrimental effect on color stability of irradiated samples

  2. Computational and experimental studies on oxalic acid imprinted ...

    Indian Academy of Sciences (India)

    e-mail: rkkawadkar@chm.vnit.ac.in. MS received 13 ... vent or porogen to form a pre-polymerization complex, followed by .... tered off and the filtrate was analysed for oxalic acid by. UV/VIS ... The experimental binding data were fitted to the.

  3. Nitrate, Nitrite, and Ammonium Variability in Drinking Water Distribution Systems.

    Science.gov (United States)

    Schullehner, Jörg; Stayner, Leslie; Hansen, Birgitte

    2017-03-09

    Accurate assessments of exposure to nitrate in drinking water is a crucial part of epidemiological studies investigating long-term adverse human health effects. However, since drinking water nitrate measurements are usually collected for regulatory purposes, assumptions on (1) the intra-distribution system variability and (2) short-term (seasonal) concentration variability have to be made. We assess concentration variability in the distribution system of nitrate, nitrite, and ammonium, and seasonal variability in all Danish public waterworks from 2007 to 2016. Nitrate concentrations at the exit of the waterworks are highly correlated with nitrate concentrations within the distribution net or at the consumers' taps, while nitrite and ammonium concentrations are generally lower within the net compared with the exit of the waterworks due to nitrification. However, nitrification of nitrite and ammonium in the distribution systems only results in a relatively small increase in nitrate concentrations. No seasonal variation for nitrate, nitrite, or ammonium was observed. We conclude that nitrate measurements taken at the exit of the waterworks are suitable to calculate exposures for all consumers connected to that waterworks and that sampling frequencies in the national monitoring programme are sufficient to describe temporal variations in longitudinal studies.

  4. Nitrite and nitroso compounds can serve as specific catalase inhibitors.

    Science.gov (United States)

    Titov, Vladimir Yu; Osipov, Anatoly N

    2017-03-01

    We present evidence that nitrite and nitrosothiols, nitrosoamines and non-heme dinitrosyl iron complexes can reversibly inhibit catalase with equal effectiveness. Catalase activity was evaluated by the permanganatometric and calorimetric assays. This inhibition is not the result of chemical transformations of these compounds to a single inhibitor, as well as it is not the result of NO release from these substances (as NO traps have no effect on the extent of inhibition). It was found that chloride and bromide in concentration above 80 mM and thiocyanate in concentration above 20 μM enhance catalase inhibition by nitrite and the nitroso compounds more than 100 times. The inhibition degree in this case is comparable with that induced by azide. We propose that the direct catalase inhibitor is a positively charged NO-group. This group acquires a positive charge in the active center of enzyme by interaction of nitrite or nitroso compounds with some enzyme groups. Halides and thiocyanate protect the NO + group from hydration and thus increase its inhibition effect. It is probable that a comparatively low chloride concentration in many cells is the main factor to protect catalase from inhibition by nitrite and nitroso compounds.

  5. Kaleidoscopic Views in the Bone Marrow: Oxalate Crystals in a Patient Presenting with Bicytopenia

    Directory of Open Access Journals (Sweden)

    Yelda Dere

    2016-03-01

    Full Text Available Pancytopenia associated with BM infiltration of different deposits is a rare condition mostly associated with amyloidosis or the accumulation of iron. One of the rarest deposits in the BM is oxalate crystals due to hyperoxaluria [1,2,3]. Primary hyperoxaluria, a genetic disorder due to mutation in the alanine glyoxylate aminotransferase gene, located on chromosome 2q37.3 and resulting in the conversion of glyoxylate to oxalate, is characterized by increased production of oxalic acid because of the specific liver enzyme deficiency and generally presents with renal stones, renal or liver failure, and oxalosis [4]. Calcium oxalate may even be deposited into various tissues such as those of the retina, peripheral nerves, arterial media, and heart [4,5]. The medical history of nephrolithiasis at early ages, characteristic appearance of birefringent crystals forming rosettes in the BM, and the envelope-like forms in the BM aspirates seen in our case supported the diagnosis of primary hyperoxaluria, which is best confirmed by genetic studies and treated with liver transplantation because of the location of the abnormal enzymes in the hepatocytes.

  6. Morphological control of calcium oxalate particles in the presence of poly-(styrene-alt-maleic acid)

    International Nuclear Information System (INIS)

    Yu Jiaguo; Tang Hua; Cheng Bei; Zhao Xiujian

    2004-01-01

    Calcium oxalate (CaOx) particles exhibiting different shapes and phase structures were fabricated by a simple precipitation reaction of sodium oxalate with calcium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA) as a crystal modifier at room temperature. The as-obtained products were characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of reaction conditions including pH, [Ca 2+ ]/[C 2 O 4 2- ] ratio and concentration of PSMA and CaC 2 O 4 on the crystal forms and morphologies of the as-obtained calcium oxalate were investigated. The results show that various crystal morphologies of calcium oxalate, such as parallelograms, plates, spheres, bipyramids etc. can be obtained depending on the experimental conditions. Higher polymer concentration favors formation of the metastable calcium oxalate dihydrate (COD) crystals. Lower pH is beneficial to the formation of plate-like CaOx crystals. Especially, the monodispersed parallelogram-like CaOx crystals can be produced by PSMA as an additive at pH 2. PSMA may act as a good inhibitor for urolithiasis since it induces the formation of COD and reduces the particle size of CaOx. This research may provide new insight into the morphological control of CaOx particles and the prevention of urolithiasis

  7. Effect of Ethylenediaminetetraacetic Acid and Ammonium Oxalate ...

    African Journals Online (AJOL)

    ADOWIE PERE

    acid and ammonium oxalate on the prevalence of microorganisms and removal of aluminum in soil by bitter leaf plant (Vernonia ... highest accumulation of aluminium in the root (16.92mg/kg); however concentrations of aluminium in the roots were .... whereas the sulphate was 13.75mg/kg. Table 2: The total colony count of ...

  8. A Family Clustered Nitrite Intoxication Investigation in Gaoxin District, Suzhou, China, 2013.

    Science.gov (United States)

    Wang, Ruiping; Teng, Chengang; Zhang, Ning; Zhang, Jun; Conway, George

    2013-12-01

    In April, 2013, a Suzhou Hospital reported a nitrite intoxication patient in coma as well as 2 family members with the similar symptom 5 days ahead. We investigated the event to identify the cause, source and possible pollution ways of the contamination. We defined case as any person living in YSHY community who has cyanosis and with at least one of the following symptoms: dizziness, headache, fatigue, tachycardia, drowsiness, nausea, vomiting, abdominal pain or diar-rhea during April 15 to April 25, 2013. We searched for case by interviewing community residents and reviewing clinics' medical records; information was then retrospectively collected on the patient's food history, cooking procedures and food sources. We identified 3 nitrite intoxication cases, 1 male and 2 female from a family. The interval time between dinner and onset was mix asparagus' on April 17 and 'scrambled asparagus' on April 21 were suspected foods. Both suspected dishes had 'sugar' added, sourced from a clean-up of a neighboring rental house. Nitrite was detected in a vomitus sample, the 'sugar' and two leftover food samples. This family clustered nitrite intoxication was induced by using unidentified nitrite as sugar to cook dishes. We recommend sodium nitrite should be dyed with bright colors to avoid mistaking it for plain salt or sugar, health departments strengthen food hygiene propaganda to improve people's recognition of food safety, and to alert them the dangerous of eating unidentified or unknown source food.

  9. Enhanced Activity and Selectivity of Carbon Nanofiber Supported Pd Catalysts for Nitrite Reduction

    KAUST Repository

    Shuai, Danmeng; Choe, Jong Kwon; Shapley, John R.; Werth, Charles J.

    2012-01-01

    Pd-based catalyst treatment represents an emerging technology that shows promise to remove nitrate and nitrite from drinking water. In this work we use vapor-grown carbon nanofiber (CNF) supports in order to explore the effects of Pd nanoparticle size and interior versus exterior loading on nitrite reduction activity and selectivity (i.e., dinitrogen over ammonia production). Results show that nitrite reduction activity increases by 3.1-fold and selectivity decreases by 8.0-fold, with decreasing Pd nanoparticle size from 1.4 to 9.6 nm. Both activity and selectivity are not significantly influenced by Pd interior versus exterior CNF loading. Consequently, turnover frequencies (TOFs) among all CNF catalysts are similar, suggesting nitrite reduction is not sensitive to Pd location on CNFs nor Pd structure. CNF-based catalysts compare favorably to conventional Pd catalysts (i.e., Pd on activated carbon or alumina) with respect to nitrite reduction activity and selectivity, and they maintain activity over multiple reduction cycles. Hence, our results suggest new insights that an optimum Pd nanoparticle size on CNFs balances faster kinetics with lower ammonia production, that catalysts can be tailored at the nanoscale to improve catalytic performance for nitrite, and that CNFs hold promise as highly effective catalyst supports in drinking water treatment. © 2012 American Chemical Society.

  10. Enhanced Activity and Selectivity of Carbon Nanofiber Supported Pd Catalysts for Nitrite Reduction

    KAUST Repository

    Shuai, Danmeng

    2012-03-06

    Pd-based catalyst treatment represents an emerging technology that shows promise to remove nitrate and nitrite from drinking water. In this work we use vapor-grown carbon nanofiber (CNF) supports in order to explore the effects of Pd nanoparticle size and interior versus exterior loading on nitrite reduction activity and selectivity (i.e., dinitrogen over ammonia production). Results show that nitrite reduction activity increases by 3.1-fold and selectivity decreases by 8.0-fold, with decreasing Pd nanoparticle size from 1.4 to 9.6 nm. Both activity and selectivity are not significantly influenced by Pd interior versus exterior CNF loading. Consequently, turnover frequencies (TOFs) among all CNF catalysts are similar, suggesting nitrite reduction is not sensitive to Pd location on CNFs nor Pd structure. CNF-based catalysts compare favorably to conventional Pd catalysts (i.e., Pd on activated carbon or alumina) with respect to nitrite reduction activity and selectivity, and they maintain activity over multiple reduction cycles. Hence, our results suggest new insights that an optimum Pd nanoparticle size on CNFs balances faster kinetics with lower ammonia production, that catalysts can be tailored at the nanoscale to improve catalytic performance for nitrite, and that CNFs hold promise as highly effective catalyst supports in drinking water treatment. © 2012 American Chemical Society.

  11. Inhibition of phosphorylation and incorporation of thymidine in Duckweed (Lemna minor L. ) by sulfur dioxide and sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Braendle, R; Stoeckli, B; Erismann, K H

    1975-05-15

    As there appears to be no thymidine kinase in duckweed (Lemna minor L.), thymidine seems to be phosphorylated by a nucleoside phosphotransferase. Phosphorylation and incorporation are inhibited by sulfur compounds such as sulfur dioxide and sulfite. The data are discussed in relation to the physiological effect of the air pollutant (SO2) on plant life. 12 references, 2 tables.

  12. Effect of Electrolytes on the Adsorption of Nitrite and Nitrate from ...

    African Journals Online (AJOL)

    Nitrite and nitrate levels were quantitatively adsorbed to wood-derived activated carbon in aqueous system and the effects of electrolytes investigated in this study using batch sorption process. The data showed that nitrate adsorbed nearly 1.5 times higher than that of nitrite. The adsorption is adequately explained by ...

  13. Isolation of Ochrobactrum sp.QZ2 from sulfide and nitrite treatment system

    International Nuclear Information System (INIS)

    Mahmood, Qaisar; Hu Baolan; Cai Jing; Zheng Ping; Azim, Muhammad Rashid; Jilani, Ghulam; Islam, Ejazul

    2009-01-01

    A bacterial strain QZ2 was isolated from sludge of anoxic sulfide-oxidizing (ASO) reactor. Based on 16S rDNA sequence analysis and morphology, the isolate was identified as Ochrobactrum sp. QZ2. The strain was facultative chemolithotroph, able of using sulfide to reduce nitrite anaerobically. It produced either elemental sulfur or sulfate as the product of sulfide oxidation, depending on the initial sulfide and nitrite concentrations. The optimum growth pH and temperature for Ochrobactrum sp. QZ2 were found as 6.5-7.0 and 30 deg. C, respectively. The specific growth rate (μ) was found as 0.06 h -1 with a doubling time of 19.75 h; the growth seemed more sensitive to highly alkaline pH. Ochrobactrum sp. QZ2 catalyzed sulfide oxidation to sulfate was more sensitive to sulfide compared with nitrite as indicated by IC 50 values for sulfide and nitrite utilization implying that isolate was relatively more tolerant to nitrite. The comparison of physiology of Ochrobactrum sp. QZ2 with those of other known sulfide-oxidizing bacteria suggested that the present isolate resembled to Ochrobactrum anthropi in its denitrification ability.

  14. Isolation of thermophilic Desulfotomaculum strains with methanol and sulfite from solfataric mud pools, and characterization of Desulfotomaculum solfataficum sp nov

    NARCIS (Netherlands)

    Goorissen, H.P.; Boschker, H.T.S.; Stams, A.J.M.; Hansen, T.A.

    2003-01-01

    Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

  15. Isolation of thermophilic Desulfotomaculum strains with methanol and sulfite from solfataric mud pools, and characterization of Desulfotomaculum solfataficum sp nov

    NARCIS (Netherlands)

    Goorissen, HP; Boschker, HTS; Stams, AJM; Hansen, TA

    Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

  16. The use of atmospheric pressure plasma-treated water as a source of nitrite for emulsion-type sausage.

    Science.gov (United States)

    Jung, Samooel; Kim, Hyun Joo; Park, Sanghoo; In Yong, Hae; Choe, Jun Ho; Jeon, Hee-Joon; Choe, Wonho; Jo, Cheorun

    2015-10-01

    We investigated the possible use of atmospheric pressure plasma-treated water (PTW) as a nitrite source in curing process. Emulsion-type sausages were manufactured with PTW, celery powder containing nitrite, and synthetic sodium nitrite at a concentration of nitrite ion 70mgkg(-1). In terms of sausage quality, there were no noticeable effects of PTW on the total aerobic bacterial counts, color, and peroxide values of sausages compared with those of celery powder and sodium nitrite throughout 28days of storage at 4°C. Sausage with added PTW had lower concentrations of residual nitrite compared to those of added celery powder and sodium nitrite during the storage period (Pnitrite-treated sausages were not different, whereas the sausage with added celery powder received the lowest scores in taste and acceptability. From the results, it is concluded that PTW can be used as a nitrite source equivalent to a natural curing agent. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Neutralization of wastewater from nitrite passivation

    International Nuclear Information System (INIS)

    Pawlowski, L.; Mientki, B.; Wasag, H.

    1982-01-01

    A method for neutralization of wastewater formed in nitrite passivation has been presented. The method consists of introducing urea into wastewater and acidifying it with sulphuric acid. Wastewater is neutralized with lime. After clarification, wastewater can be drained outside the plant

  18. Preliminary nitrite, nitrate and colour analysis of Malaysian edible bird’s nest

    OpenAIRE

    Quek, Meei Chien; Chin, Nyuk Ling; Yusof, Yus Aniza; Tan, Sheau Wei; Law, Chung Lim

    2015-01-01

    The high nitrite content in edible bird’s nests is a major concern to the local swiftlet industry. It lowers the price of the edible bird’s nests and it brings severe health hazards to consumers and farmers. This research investigated the nitrite and nitrate contents of eight types of local edible bird’s nests by using ion chromatography system and evaluating its colour using the CIE system in L∗a∗b∗ parameters. The nitrite content obtained ranged from 5.7 μg/g for the house nests to 843.8 μg...

  19. Two novel metal-organic coordination polymers based on diphosphonate and oxalate: Synthesis, structures and properties

    Science.gov (United States)

    Niu, Qing-Jun; Zheng, Yue-Qing; Zhou, Lin-Xia; Zhu, Hong-Lin

    2015-07-01

    Two 2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonato and oxalic acid bridged coordination polymers (H2en)[Co3(H2zdn)2(ox)(H2O)2] (1) and Cd2(H2zdn)(ox)0.5(H2O) (2) (2-(1-imidazole)-1-hydroxyl-1,1'-ethylidenediphosphonic acid=H5zdn; oxalic acid=H2ox) were synthesized under hydrothermal conditions and characterized by the infrared (IR), thermogravimetric analyses (TGA), elemental analyses (EA) and X-ray diffraction (XRD). Compound 1 is bridged by phosphonate anions to 1D chain, and further linked by oxalate anions to 2D layer. Compound 2 is bridged by O-P-O units of H5zdn to the layer, and then pillared by oxalate anions to generate 3D frameworks. Compound 1 shows anti-ferromagnetic behaviors analyzed with the temperature-dependent zero-field ac magnetic susceptibilities, while compound 2 exhibits an influence on the luminescent property.

  20. Conductance and bulk vertical detachment energy of hydrated sulphate and oxalate dianions: a theoretical study

    Science.gov (United States)

    Pathak, Arup Kumar

    2014-06-01

    Analytical expressions have been derived for the vertical detachment energy (VDE) for hydrated sulphate (SO2 -4) and oxalate (C2O2 -4) dianions that can be used to calculate the same over a wide range of cluster sizes including the bulk from the knowledge of VDE for a finite number of stable clusters. The calculated bulk detachment energies are found to be very good in agreement (within 5%) with the available experimental results for both the systems. It is observed that two or more water molecules will be essential for the stability of sulphate and oxalate dianions against spontaneous electron loss and this is consistent with the experiment. We have, for the first time, provided a scheme to calculate the radius of the solvent berg for sulphate and oxalate dianions. The calculated conductivity values for the sulphate and oxalate dianions using Stokes-Einstein relation and the radius of solvent berg are found to be very good in agreement (within 4%) with the available experimental results.

  1. Electrochemical oxidation of sulfites by DWCNTs, MWCNTs, higher fullerenes and manganese

    Science.gov (United States)

    Uzun, Dzhamal; Pchelarov, George; Dimitrov, Ognian; Vassilev, Sasho; Obretenov, Willi; Petrov, Konstantin

    2018-03-01

    Different electrocatalysts were tested for oxidation of sulfites to sulfates, namely, manganese thin films deposited on fullerenes and carbon nanotubes. The results presented clearly show that electrodes containing HFs (higher fullerenes), DWCNTs (double-wall carbon nanotubes) and manganese acetate are effective catalysts in S/O2 fuel cells. HFs and DWCNTs have high catalytic activity and can be employed as standalone catalysts. Manganese was deposited on DWCNTs, HFs and fullerenes C60/C70 by a thermal process. The electrocatalysts were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical testing was carried out by plotting the E/V polarization curve. The polarization curves of the electrodes composed of pristine DWCNTs showed the lowest overpotentials.

  2. Combined effects of high hydrostatic pressure and sodium nitrite on color, water holding capacity and texture of frankfurter

    Science.gov (United States)

    Jonas, G.; Csehi, B.; Palotas, P.; Toth, A.; Kenesei, Gy; Pasztor-Huszar, K.; Friedrich, L.

    2017-10-01

    The aim of this study was to investigate the effect of sodium nitrite and high hydrostatic pressure on the color, water holding capacity (WHC) and texture characteristics of frankfurter. Three hundred, 450 and 600 MPa (5 minutes; 20 °C) and 50, 75, 100 and 125 ppm (calculated on weight of meat) sodium nitrite were applied. Parameters were measured right after the pressure treatment. Data were evaluated with two-way analysis of variance (p 0.05) with pressure levels and sodium nitrite amounts as factors. Nitrite reduction significantly increased lightness (L*) and resulted in decreased redness (a*) value. The pressure treatments decreased the lightness at all nitrite concentrations and did not significantly affect the red color of frankfurters. Fifty and 75 ppm nitrite and pressurization at 300 or 450 MPa improved the water holding property of frankfurter. The pressure treatment did not significantly affect the WHC but changing the nitrite amount had significant effect on it. Interactive effect occurred between pressure levels and nitrite concentrations for hardness. The pressure treatment increased and the nitrite reduction decreased hardness. Significant changes were found in cohesiveness at 450 and 600 MPa in frankfurters containing 50 and 75 ppm nitrite: pressure treatment at higher levels and nitrite reduction decreased the value of cohesiveness.

  3. Growth and physico chemical characterization of lanthanum neodymium oxalate single crystals

    International Nuclear Information System (INIS)

    Raju, K.S.; John, Varughese; Ittyachen, M.A.

    1998-01-01

    Single crystals of lanthanum neodymium oxalate (LNO) are grown in sodium meta silicate gels, by the diffusion of a mixture of aqueous solutions of lanthanum nitrate and neodymium nitrate into the test tube having the set gel containing oxalic acid. The bluish pink coloured tabular crystals of LNO having well defined hexagonal basal planes appear either as foggy or clear, the latter at the greater depths inside the gel. The coloration of LNO visually observed is evidenced in UV-visible spectrum, by the revelation of well pronounced characteristic peaks in the visible region (500-900 nm). X-ray diffraction (XRD) of powdered LNO is ordered, meaning crystalline in nature, besides its isostructurality with similarly grown lanthanum samarium oxalate crystals. The single crystallinity of LNO is established by its oscillation XRD pattern. Thermogravimetric analysis (TGA) and differential scanning colorimetry (DSC) support that LNO loses water of crystallization around 120 degC and CO and CO 2 around 350-450 degC, while the infrared absorption (IR) spectrum of LNO establishes the presence of oxalate (C 2 O 4 ) 2- ions. Energy dispersive x-ray analysis (EDAX) confirms the presence of La and Nd in the sample. X-ray photoelectron spectroscopic (XPS) studies of LNO establish the presence of La and Nd in their respective oxide states. An empirical structure for LNO has been proposed on the basis of these findings. The smokiness in the foggy LNO crystal has been attributed due to the gel inclusion during the growth process. (author)

  4. Colorimetric sensing of oxalate based on its inhibitory effect on the reaction of Fe (III) with curcumin nanoparticles

    Science.gov (United States)

    Pourreza, Nahid; Lotfizadeh, Neda; Golmohammadi, Hamed

    2018-03-01

    In this research, a new colorimetric method for the determination of oxalate using curcumin nanoparticles (CURNs) in the presence Fe (III) is introduced. The method is based on the inhibitory effect of oxalate ion on the reaction of (CURNs) with Fe (III) in acidic media. This reaction was monitored by measuring the increase in absorbance of CURNs-Fe3 + complex in the presence of oxalate ion at 427 nm. The effect of different parameters such as the pH of the sample solution, concentration of Fe (III), concentration of CURNs and the reaction time was examined and optimized. Under optimum experimental conditions, the absorption intensity was linear with the concentration of oxalate in the range of 0.15 to 1.70 μg mL- 1. The limit of detection (LOD) was 0.077 μg mL- 1 and the relative standard deviations (RSD) for 8 replicate measurements of 0.40 and 1.05 μg mL- 1 of oxalate were 4.20% and 2.74%, respectively. The developed method was successfully employed to the determination of oxalate in water, food and urine samples with satisfactory results.

  5. Oxalate-metabolising genes of the white-rot fungus Dichomitus squalens are differentially induced on wood and at high proton concentration

    NARCIS (Netherlands)

    Mäkelä, Miia R; Sietiö, Outi-Maaria; de Vries, Ronald P; Timonen, Sari; Hildén, Kristiina; van den Brink, J.

    2014-01-01

    Oxalic acid is a prevalent fungal metabolite with versatile roles in growth and nutrition, including degradation of plant biomass. However, the toxicity of oxalic acid makes regulation of its intra- and extracellular concentration crucial. To increase the knowledge of fungal oxalate metabolism, a

  6. Effect of Lagenaria siceraria fruit powder on sodium oxalate induced urolithiasis in Wistar rats

    Directory of Open Access Journals (Sweden)

    Rahul V Takawale

    2012-01-01

    Full Text Available Background: In spite of advances in the present practice of medicine, the formation and growth of calculi continues to trouble mankind, as there is no satisfactory drug to treat kidney stones. In India, many indigenous drugs are in use for the treatment of urinary calculus disease. Objective: The present study was intended to determine anti-urolithiatic effect of Lagenaria siceraria fruit powder (LSFP against sodium oxalate (NaOx induced urolithiasis in rats. Materials and Methods: Animals were grouped as Vehicle Group (received vehicle gum acacia 2% w/v 1 mL/kg/p.o., NaOx Group(Sodium oxalate 70 mg/kg,i.p., LSFP Group (500 mg/kg, p.o. LSFP suspended in gum acacia 2% + Sodium oxalate 70 mg/kg, Cystone Group (500 mg/kg, p.o. Cystone suspended in gum acacia 2% + Sodium oxalate 70 mg/kg. Result: The increased severity of microscopic calcium oxalate (CaOx crystals deposition along with increased concentration in the kidney was seen after 7 days of NaOx (70 mg/kg, i.p. pre-treatment. LSFP (500 mg/kg, p.o. and standard marketed formulation Cystone (500 mg/kg, p.o. caused a significant reversal of NaOx-induced changes in ion excretion and urinary CaOx concentration in 7 days treatment. Conclusion: From the results, it was concluded that LSFP showed beneficial effect against urolithiasis by decreasing CaOx excretion and preventing crystal deposition in the kidney tubules.

  7. Fasting urinary calcium-to-creatinine and oxalate-to-creatinine ratios in dogs with calcium oxalate urolithiasis and breed-matched controls.

    Science.gov (United States)

    Furrow, E; Patterson, E E; Armstrong, P J; Osborne, C A; Lulich, J P

    2015-01-01

    Hypercalciuria and hyperoxaluria are risk factors for calcium oxalate (CaOx) urolithiasis, but breed-specific reports of urinary metabolites and their relationship with stone status are lacking. To compare urinary metabolites (calcium and oxalate) and blood ionized calcium (iCa) concentrations between CaOx stone formers and breed-matched stone-free controls for the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. Forty-seven Miniature Schnauzers (23 cases and 24 controls), 27 Bichons Frise (14 cases and 13 controls), and 15 Shih Tzus (7 cases and 8 controls). Prospective study. Fasting spot urinary calcium-to-creatinine and oxalate-to-creatinine ratios (UCa/Cr and UOx/Cr, respectively) and blood iCa concentrations were measured and compared between cases and controls within and across breeds. Regression models were used to test the effect of patient and environmental factors on these variables. UCa/Cr was higher in cases than controls for each of the 3 breeds. In addition to stone status, being on a therapeutic food designed to prevent CaOx stone recurrence was associated with higher UCa/Cr. UOx/Cr did not differ between cases and controls for any of the breeds. Blood iCa was higher in cases than controls in the Miniature Schnauzer and Bichon Frise breeds and had a moderate correlation with UCa/Cr. Hypercalciuria is associated with CaOx stone status in the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. UOx/Cr did not correlate with stone status in these 3 breeds. These findings may influence breed-specific stone prevention recommendations. Copyright © 2015 by the American College of Veterinary Internal Medicine.

  8. Vanillin: Synthetic Flavoring from Spent Sulfite Liquor

    Science.gov (United States)

    Hocking, Martin B.

    1997-09-01

    Separation of the lignin component of wood from the cellulose presents an opportunity to access various interesting products from the lignin fragments. The lignin represents availability of a sizable renewable resource. Vanillin, or 3-methoxy-4-hydroxybenzaldehyde, is one of a series of related substituted aromatic flavor constituents, and represents one of the potentially profitable possibilities. Vanillin production from the lignin-containing waste liquor obtained from acid sulfite pulping of wood began in North America in the mid 1930's. By 1981 one plant at Thorold, Ontario produced 60% of the contemporary world supply of vanillin. The process also simultaneously decreased the organic loading of the aqueous waste streams of the pulping process. Today, however, whilst vanillin production from lignin is still practiced in Norway and a few other areas, all North American facilities using this process have closed, primarily for environmental reasons. New North American vanillin plants use petrochemical raw materials. An innovation is needed to help overcome the environmental problems of this process before vanillin production from lignin is likely to resume here. Current interest in the promotion of chemicals production from renewable raw materials reinforces the incentive to do this.

  9. Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

    International Nuclear Information System (INIS)

    Rudisill, T.S.

    1999-01-01

    Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitation process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the beta dec

  10. Energetics and kinetics of ferrocyanide and nitrate/nitrite reactions

    International Nuclear Information System (INIS)

    Scheele, R.D.; Burger, L.L.; Sell, R.L.

    1994-01-01

    During the 1950's, radiocesium scavenging at the Hanford site resulted in radioactive waste sludges containing ferrocyanide, nitrate, and nitrite. These waters are a concern since certain mixtures of ferrocyanide and nitrate and/or nitrite are known to explode when heated. The authors have used differential scanning calorimetry, thermogravimetric analysis, isothermal calorimetry and gravimetry, and accelerating rate calorimetry to measure the thermal behavior, the reaction enthalpies, and selected kinetic parameters for reactions between sodium nickel ferrocyanide, the suspected ferrocyanide form in Hanford wastes, and nitrate and/or nitrite. These studies indicate that the oxidation proceeds via multiple steps, the initial reaction begins near 200 degrees C, the initial step has a high activation energy (>200 kJ/mole-K), succeeding reaction steps have activation energies ranging from 90 to 160 kJ/mole-K, and that the oxidation yields about 50% of the theoretical heat of reaction for the most energetic reaction

  11. Spectrophotometric determination of nitrite in simulated Purex Process solutions

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, I.daC. de; Matsuda, H T; Araujo, B.F. de; Araujo, J.A. de

    1984-01-01

    A spectrophotometric method for nitrite determination in simulated Purex Process solutions is presented, utilizing the Griess reagent for the formation of the coloured azocompound with an absorption maximum at 525 nm. Molar absortivity was 36,262 and the sensitivity of the method 10/sup -6/M for nitrite. The calibration curve is linear in the range of 2 to 30..mu..g NO/sup -//sub 2//25 ml in cells of 1 cm optical path. The method can be used in the presence of uranium up to limits of an U/NO/sup -//sub 2/ ratio of 150. Test solutions were prepared to simulate composition and concentrations as obtained by irradiating standard fuel with a neutro flux of 3.2 x 10/sup 13/ n.s/sup -1/.cm/sup -2/, with a burn-up value of 33,000 Mwd/T and cooling time of two years. Nitrite determinations in these solutions were accurate within limits of 5%.

  12. Determination of five abused drugs in nitrite-adulterated urine by immunoassays and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Tsai, S C; ElSohly, M A; Dubrovsky, T; Twarowska, B; Towt, J; Salamone, S J

    1998-10-01

    The adulteration of urine specimens with nitrite ion hasseen shown to mask the gas chromatography-mass spectrometry (GC-MS) confirmation testing of marijuana use. This study was designed to further investigate the effect of nitrite adulteration on the detection of five commonly abused drugs by immunoassay screening and GC-MS analysis. The drugs tested are cocaine metabolite (benzoylecgonine), morphine, 11-nor-delta-tetrahydrocannabinol-9-carboxylic acid (THCCOOH), amphetamine, and phencyclidine. The immunoassays evaluated included the instrument-based Abuscreen ONLINE assays, the on-site Abuscreen ONTRAK assays, and the one-step ONTRAK TESTCUP-5 assay. Multianalyte standards containing various levels of drugs were used to test the influence of both potassium and sodium nitrite. In the ONLINE immunoassays, the presence of up to 1.0M nitrite in the multianalyte standards had no significant effect for benzoylecgonine, morphine, and phencyclidine assays. With a high concentration of nitrite, ONLINE became more sensitive for amphetamine (detected more drug than what was expected) and less sensitive for THCCOOH (detected less drug than what was expected). No effects of nitrite were observed on the results of the Abuscreen ONTRAK assays. Similarly, no effects were observed on the absolute qualitative results of the TESTCUP-5 when testing the nitrite-adulterated standards. However, the produced intensities of the signals that indicate the negative test results were slightly lowered in the THC and phencyclidine assays. The presence of 1.0M of nitrite did not show dramatic interference with the GC-MS analysis of benzoylecgonine, morphine, amphetamine, and phencyclidine. In contrast, nitrite ion significantly interfered with the detection of THCCOOH by GC-MS. The presence of 0.03M of nitrite ion resulted in significant loss in the recovery of THCCOOH and its internal standard by GC-MS. The problem of nitrite adulteration could be alleviated by sodium bisulfite treatment even

  13. Detection of nitrite based on fluorescent carbon dots by the hydrothermal method with folic acid

    Science.gov (United States)

    Lin, Haitao; Ding, Liyun; Zhang, Bingyu; Huang, Jun

    2018-05-01

    A fluorescent carbon dots probe for the detection of aqueous nitrite was fabricated by a one-pot hydrothermal method, and the transmission electron microscope, X-ray diffractometer, UV-Vis absorption spectrometer and fluorescence spectrophotometer were used to study the property of carbon dots. The fluorescent property of carbon dots influenced by the concentration of aqueous nitrite was studied. The interaction between the electron-donating functional groups and the electron-accepting nitrous acid could account for the quenching effect on carbon dots by adding aqueous nitrite. The products of the hydrolysis of aqueous nitrite performed a stronger quenching effect at lower pH. The relationship between the relative fluorescence intensity of carbon dots and the concentration of nitrite was described by the Stern-Volmer equation (I0/I - 1 = 0.046[Q]) with a fine linearity (R2 = 0.99). The carbon dots-based probe provides a convenient method for the detection of nitrite concentration.

  14. Haematological and ion regulatory effects of nitrite in the air-breathing snakehead fish Channa striata

    DEFF Research Database (Denmark)

    Lefevre, Sjannie; Jensen, Frank B.; Huong, Do T.T.

    2012-01-01

    M. Effects of sub-lethal exposures to nitrite (0 mM, 1.4 mM, and 3.0 mM) were determined during a 7-day exposure period. Plasma nitrite increased, but the internal concentration remained well below ambient levels. Extracellular nitrate rose by several mM, indicating that a large proportion of the nitrite...... taken up was converted to nitrate. Nitrite reacted with erythrocyte haemoglobin (Hb) causing methaemoglobin (metHb) to increase to 30% and nitrosylhaemoglobin (HbNO) to increase to 10% of total Hb. Both metHb and HbNO stabilised after 4 days, and functional Hb levels accordingly never fell below 60......The tolerance and effects of nitrite on ion balance and haematology were investigated in the striped snakehead, Channa striata Bloch 1793, which is an air-breathing fish with reduced gills of importance for aquaculture in South East Asia. C. striata was nitrite tolerant with a 96 h LC50 of 4.7 m...

  15. Effect of dentin pretreatment with potassium oxalate: analysis of microtensile bond strengths and morphologic aspects.

    Science.gov (United States)

    De Moraes Porto, Isabel Cristina Celerino; De Andrade, Ana Karina Maciel; Alves, Luiz Carlos; Braz, Rodivan

    2012-02-01

    An effective and stable bond is the most desirable characteristic of contemporary adhesive systems. The aim of this study was to evaluate the effect of potassium oxalate on dentin/resin bond strength. Dentin on the occlusal surface of human premolars was exposed and etched with 35% phosphoric acid, to receive 3% monohydrated potassium oxalate and the following adhesive systems: Scotchbond Multipurpose (SMO; 3M/ESPE) and Prime & Bond NT (PBO; Dentsply), followed by the application of resin composite (Z250; 3M/ESPE). The control groups (SM and PB) did not receive potassium oxalate application. The prepared teeth were kept in distilled water at 37°C for 24 h and 12 months. They were then cut longitudinally into sticks with a bond area of ∼0.8 mm(2) for submission to the microtensile bond strength test. The data were analyzed by two-factor ANOVA, Tamhane's paired comparisons, and the Student t-test (α = 0.05). The hybrid layer formed was observed by scanning electron microscopy (SEM). SEM analysis of the surfaces treated with PB revealed shorter resin tags associated with the application of potassium oxalate, whereas SM showed tags similar to those without potassium oxalate. A significant difference was shown between the two storage times for each of the protocols. There was a significant difference among SMO, SM, and PBO (24 h), as well as among SM, SMO, and PBO, and between PB and PBO (12 months). The application of potassium oxalate before conventional adhesive systems may result in alteration of the bond strength between dentin and resin composite, depending on the material. Copyright © 2011 Wiley Periodicals, Inc.

  16. Effects of reactive Mn(III)-oxalate complexes on structurally intact plant cell walls

    Science.gov (United States)

    Summering, J. A.; Keiluweit, M.; Goni, M. A.; Nico, P. S.; Kleber, M.

    2011-12-01

    Lignin components in the in plant litter are commonly assumed to have longer residence times in soil than many other compounds, which are supposedly, more easily degradable. The supposed resistance of lignin compounds to decomposition is generally attributed to the complex chain of biochemical steps required to create footholds in the non-porous structure of ligno-cellulose in cell walls. Interestingly, Mn(III) complexes have shown the ability to degrade ligno-cellulose. Mn(III) chelated by ligands such as oxalate are soluble oxidizers with a high affinity for lignin structures. Here we determined (i) the formation and decay kinetics of the Mn(III)-oxalate complexes in aqueous solution and (ii) the effects that these complexes have on intact ligno-cellulose. UV/vis spectroscopy and iodometric titrations confirmed the transient nature of Mn(III)-oxalate complexes with decay rates being in the order of hours. Zinnia elegans tracheary elements - a model ligno-cellulose substrate - were treated with Mn(III)-oxalate complexes in a newly developed flow-through reactor. Soluble decomposition products released during the treatment were analyzed by GC/MS and the degree of cell integrity was measured by cell counts, pre- and post-treatment counts indicate a decrease in intact Zinnia elegans as a result of Mn(III)-treatment. GC/MS results showed the release of a multitude of solubilized lignin breakdown products from plant cell walls. We conclude that Mn(III)-oxalate complexes have the ability to lyse intact plant cells and solubilize lignin. Lignin decomposition may thus be seen as resource dependent, with Mn(III) a powerful resource that should be abundant in terrestrial characterized by frequent redox fluctuations.

  17. Co-treatment with conjugated linoleic acid and nitrite protects against myocardial infarction

    Directory of Open Access Journals (Sweden)

    Natia Qipshidze-Kelm

    2014-01-01

    Full Text Available According to the CDC, the most common type of heart disease is coronary artery disease, which commonly leads to myocardial infarction (MI. Therapeutic approaches to lessen the resulting cardiovascular injury associated with MI are limited. Recently, MicroRNAs (miRNAs have been shown to act as negative regulators of gene expression by inhibiting mRNA translation and/or stimulating mRNA degradation. A single miRNA can modulate physiological or disease phenotypes by regulating whole functional systems. Importantly, miRNAs can regulate cardiac function, thereby modulating heart muscle contraction, heart growth and morphogenesis. MicroRNA-499 (miRNA-499 is a cardiac-specific miRNA that when elevated causes cardiomyocyte hypertrophy, in turn preventing cardiac dysfunction during MI. Previous studies revealed that combination treatment with conjugated linoleic acid (cLA and nitrite preserved cardiovascular function in mice. Therefore, it was hypothesized that cLA and nitrite may regulate miRNA-499, thus providing cardiac protection during MI. To test this hypothesis, 12-week old mice were treated with cLA (10 mg/kg/d-via osmotic mini-pump or cLA and nitrite (50 ppm-drinking water 3 days prior to MI (ligation of the left anterior descending artery. Echocardiography and pressure–volume (PV-loop analysis revealed that cLA and nitrite-treated MI mice had improved heart function (10 days following MI compared to untreated MI mice. Treatment with cLA and nitrite significantly induced levels of miRNA-499 compared to untreated MI mice. In addition, treatment with cLA and nitrite abolished MI-induced protein expression of p53 and dynamin-related protein-1 (DRP-1. Moreover, the antioxidant enzyme expression of heme oxygenase-1 (HO-1 was elevated in MI mice treated with cLA and nitrite compared to untreated MI mice. Confocal imaging on heart tissue confirmed expression the levels of HO-1 and p53. Taken together, these results suggest that therapeutic

  18. Ethanol production from non-detoxified whole slurry of sulfite-pretreated empty fruit bunches at a low cellulase loading

    Science.gov (United States)

    Jinlan Cheng; Shao-Yuan Leu; J.Y. Zhu; Thomas W. Jeffries

    2014-01-01

    Sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) was applied to an empty fruit bunches (EFB) for ethanol production. SPORL facilitated delignification through lignin sulfonation and dissolution of xylan to result in a highly digestible substrate. The pretreated whole slurry was enzymatically saccharified at a solids loading of 18% using a...

  19. Reactions of nitrite with hemoglobin measured by membrane inlet mass spectrometry

    Science.gov (United States)

    Tu, Chingkuang; Mikulski, Rose; Swenson, Erik R.; Silverman, David N.

    2010-01-01

    Membrane inlet mass spectrometry was used to observe nitric oxide in the well-studied reaction of nitrite with hemoglobin. The membrane inlet was submerged in the reaction solutions and measured NO in solution via its flux across a semipermeable membrane leading to the mass spectrometer detecting the mass-to-charge ratio m/z 30. This method measures NO directly in solution and is an alternate approach compared with methods that purge solutions to measure NO. Addition to deoxy-Hb(FeII) (near 38 µM heme concentration) of nitrite in a range of 80 µM to 16 mM showed no accumulation of either NO or N2O3 on a physiologically relevant time scale with a sensitivity near 1 nM. The addition of nitrite to oxy-Hb(FeII) and met-Hb(FeIII) did not accumulate free NO to appreciable extents. These observations show that for several minutes after mixing nitrite with hemoglogin, free NO does not accumulate to levels exceeding the equilibrium level of NO. The presence of cyanide ions did not alter the appearance of the data; however, the presence of 2 mM mercuric ions at the beginning of the experiment with deoxy-Hb(FeII) shortened the initial phase of NO accumulation and increased the maximal level of free, unbound NO by about twofold. These experiments appear consistent with no role of met-Hb(FeIII) in the generation of NO and an increase in nitrite reductase activity caused by the presumed binding of mercuric to cysteine residues. These results raise questions about the ability of reduction of nitrite mediated by deoxy-Hb(FeII) to play a role in vasodilation. PMID:18848984

  20. Thermodynamic analysis of stability in iron removal from kaolin by using oxalic acid

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    C. Ocampo-López

    2013-06-01

    Full Text Available The graphical representation of global stability for a system, or Pourbaix diagram, was constructed to perform a thermodynamic study of iron removal from kaolin using oxalic acid as an oxidant. To do this the free energies of formation of the oxalate complex of the system were calculated, and it was found that the more stable specie is Fe(C2O43-3, with a calculated free energy of formation of -3753.88 kcal/mol. Thermodynamic stability functions were estimated for the system as a function of pH and Eh known as potential of oxide reduction. It was built a global stability diagram for the removal system; it showed that the specie trioxalate Fe(C2O43-3 is the only oxalate in equilibrium with other compounds associated with the removal of iron in kaolin.