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Sample records for calcium perchlorates

  1. Thermodynamics of the complexation of ciprofloxacin with calcium and magnesium perchlorate

    International Nuclear Information System (INIS)

    Highlights: → The thermodynamics of the reactions of ciprofloxacin (CIP) with Ca(ClO4)2 and Mg(ClO4)2 were investigated by conductometric titration. → The reactions of CIP with each ion produce two ionic complexes with the formulas M(CIP)2+ and M(CIP)22+. → The change in enthalpy and entropy were negative which indicate that the complexation is driven by the enthalpy change. - Abstract: The thermodynamics of the reactions of ciprofloxacin (CIP) with calcium perchlorate (Ca(ClO4)2) and magnesium perchlorate (Mg(ClO4)2) have been investigated in water-methanol solvent using conductometric titration. The reactions of CIP with each ion produce two ionic complexes with the general formulas M(CIP)2+ and M(CIP)22+. The stability constants K1 and K2 at 25 oC for the complexes formed from the reaction with Ca(ClO4)2 were 8.84 x 104 and 3.62 x 104, respectively. For the reaction with Mg(ClO4)2K1 and K2 were 1.72 x 105 and 2.50 x 103, respectively. The enthalpy (ΔH1, ΔH2, ΔH12) and entropy (ΔS1, ΔS2, ΔS12) of complexation reactions were determined from the temperature dependence of the complexation constants. The reactions of CIP with both ions are accompanied by a decrease in entropy (ΔS12 = -468.12 and -478.89 J/K mol for complexation with Ca(ClO4)2 and Mg(ClO4)2, respectively) and enthalpy (ΔH12 = -193.09 and -192.01 kJ/mol for complexation with Ca(ClO4)2 and Mg(ClO4)2, respectively), which indicate that the reactions are driven by the enthalpy change.

  2. Thermodynamics of the complexation of ciprofloxacin with calcium and magnesium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Al-Mustafa, Jamil, E-mail: malkawi@just.edu.jo [Department of Applied Chemistry, Faculty of Arts and Sciences, Jordan University of Science and Technology, P.O. Box 3030, Irbid (Jordan); Taha, Ziyad A. [Department of Applied Chemistry, Faculty of Arts and Sciences, Jordan University of Science and Technology, P.O. Box 3030, Irbid (Jordan)

    2011-07-10

    Highlights: {yields} The thermodynamics of the reactions of ciprofloxacin (CIP) with Ca(ClO{sub 4}){sub 2} and Mg(ClO{sub 4}){sub 2} were investigated by conductometric titration. {yields} The reactions of CIP with each ion produce two ionic complexes with the formulas M(CIP){sup 2+} and M(CIP){sub 2}{sup 2+}. {yields} The change in enthalpy and entropy were negative which indicate that the complexation is driven by the enthalpy change. - Abstract: The thermodynamics of the reactions of ciprofloxacin (CIP) with calcium perchlorate (Ca(ClO{sub 4}){sub 2}) and magnesium perchlorate (Mg(ClO{sub 4}){sub 2}) have been investigated in water-methanol solvent using conductometric titration. The reactions of CIP with each ion produce two ionic complexes with the general formulas M(CIP){sup 2+} and M(CIP){sub 2}{sup 2+}. The stability constants K{sub 1} and K{sub 2} at 25 {sup o}C for the complexes formed from the reaction with Ca(ClO{sub 4}){sub 2} were 8.84 x 10{sup 4} and 3.62 x 10{sup 4}, respectively. For the reaction with Mg(ClO{sub 4}){sub 2}K{sub 1} and K{sub 2} were 1.72 x 10{sup 5} and 2.50 x 10{sup 3}, respectively. The enthalpy ({Delta}H{sub 1}, {Delta}H{sub 2}, {Delta}H{sub 12}) and entropy ({Delta}S{sub 1}, {Delta}S{sub 2}, {Delta}S{sub 12}) of complexation reactions were determined from the temperature dependence of the complexation constants. The reactions of CIP with both ions are accompanied by a decrease in entropy ({Delta}S{sub 12} = -468.12 and -478.89 J/K mol for complexation with Ca(ClO{sub 4}){sub 2} and Mg(ClO{sub 4}){sub 2}, respectively) and enthalpy ({Delta}H{sub 12} = -193.09 and -192.01 kJ/mol for complexation with Ca(ClO{sub 4}){sub 2} and Mg(ClO{sub 4}){sub 2}, respectively), which indicate that the reactions are driven by the enthalpy change.

  3. Perchlorate in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Martinelango, P. Kalyani [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States); Tian Kang [Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX 79409 (United States); Dasgupta, Purnendu K. [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States)]. E-mail: Sandyd@ttu.edu

    2006-05-10

    There has been no reliable published data on the presence of perchlorate in seawater. Seaweeds are among the most important plant life in the ocean and are good sources of iodine and have been widely used as food and nutritional supplement. Perchlorate is known to inhibit the transport of iodide by the sodium iodide symporter (NIS), present e.g., in the thyroid and mammary glands. With perchlorate being increasingly detected in drinking water, milk and various other foods, increasing the iodide intake through inexpensive natural supplements may be an attractive solution for maintaining iodine assimilation. We report here measurable concentrations of perchlorate in several samples of seawater (detectable in about half the samples analyzed). We also report the iodide and perchlorate concentrations of 11 different species of seaweed and the corresponding bioconcentration factors (BCF) for perchlorate and iodide, relative to the seawater from which they were harvested. All seaweed samples came from the same region, off the coast of Northeastern Maine. Concentrations of iodide and perchlorate in four seawater samples collected from the region near harvest time were 30 {+-} 11 and 0.16 {+-} 0.084 {mu}g l{sup -1}, respectively. Concentrations of both iodide and perchlorate varied over a wide range for different seaweed species; iodide ranging from 16 to 3134 mg kg{sup -1} and perchlorate from 0.077 to 3.2 mg kg{sup -1}. The Laminaria species had the highest iodide concentration; Laminaria digitata is the seaweed species most commonly used in the kelp tablets sold in health food stores. Our sample of L. digitata contained 3134 {+-} 15 mg iodide/kg dry weight. The BCF varied widely for different species, with Laminaria species concentrating iodide preferentially over perchlorate. The iodide BCF (BCF{sub i}) to perchlorate BCF (BCF{sub p}) quotient ranged from 0.66 to 53; L. digitata and L. saccarina having a BCF{sub i}/BCF{sub p} value of 45 and 53, respectively, far

  4. Breastfed infants metabolize perchlorate.

    Science.gov (United States)

    Shelor, C Phillip; Kirk, Andrea B; Dasgupta, Purnendu K; Kroll, Martina; Campbell, Catrina A; Choudhary, Pankaj K

    2012-05-01

    Bifidobacteria are the dominant intestinal bacteria in breastfed infants. It is known that they can reduce nitrate. Although no direct experiments have been conducted until now, inferred pathways for Bifidobacterium bifidum include perchlorate reduction via perchlorate reductase. We show that when commercially available strains of bifidobacteria are cultured in milk, spiked with perchlorate, perchlorate is consumed. We studied 13 breastfed infant-mother pairs who provided 43 milk samples and 39 infant urine samples, and 5 formula-fed infant-mother pairs who provided 21 formula samples and 21 infant urine samples. Using iodine as a conservative tracer, we determined the average urinary iodine (UI) to milk iodine (MI) concentration ratio to be 2.87 for the breastfed infants. For the same samples, the corresponding perchlorate concentration ratio was 1.37 (difference significant, p perchlorate is lost. For the formula fed infant group the same ratios were 1.20 and 1.58; the difference was not significant (p = 0.68). However, the small number of subjects in the latter group makes it more difficult to conclude definitively whether perchlorate reduction does or does not occur. PMID:22497505

  5. Bioelectrical Perchlorate Remediation

    Science.gov (United States)

    Thrash, C.; Achenbach, L. A.; Coates, J. D.

    2007-12-01

    Several bioreactor designs are currently available for the ex-situ biological attenuation of perchlorate- contaminated waters and recently, some of these reactor designs were conditionally approved by the California Department of Health Services for application in the treatment of perchlorate contaminated drinking water. However, all of these systems are dependent on the continual addition of a chemical electron donor to sustain microbial activity and are always subject to biofouling and downstream water quality issues. In addition, residual labile electron donor in the reactor effluent can stimulate microbial growth in water distribution systems and contribute to the formation of potentially toxic trihalomethanes during disinfection by chlorination. As part of our ongoing studies into microbial perchlorate reduction we investigated the ability of dissimilatory perchlorate reducing bacteria (DPRB) to metabolize perchlorate using a negatively charged electrode (cathode) in the working chamber of a bioelectrical reactor (BER) as the primary electron donor. In this instance the DPRB use the electrons on the electrode surface either directly or indirectly in the form of electrolytically produced H2 as a source of reducing equivalents for nitrate and perchlorate reduction. As part of this investigation our fed-batch studies showed that DPRB could use electrons from a graphite cathode poised at -500mV (vs. Ag/AgCl) for the reduction of perchlorate and nitrate. We isolated a novel organism, Dechlorospirillum strain VDY, from the cathode surface after 70 days operation which readily reduced 100 mg.L-1 perchlorate in a mediatorless batch bioelectrical reactor (BER) in 6 days. Continuous up-flow BERs (UFBERs) seeded with active cultures of strain VDY continuously treated waters containing 100 mg.L-1 perchlorate with almost 100% efficiency throughout their operation achieving a non-optimized volumetric loading of 60 mg.L-1 reactor volume.day-1. The same UFBERs also treated

  6. Sensitivity and adaptability of methanogens to perchlorates: Implications for life on Mars

    Science.gov (United States)

    Kral, Timothy A.; Goodhart, Timothy H.; Harpool, Joshua D.; Hearnsberger, Christopher E.; McCracken, Graham L.; McSpadden, Stanley W.

    2016-01-01

    In 2008, the Mars Phoenix Lander discovered perchlorate at its landing site, and in 2012, the Curiosity rover confirmed the presence of perchlorate on Mars. The research reported here was designed to determine if certain methanogens could grow in the presence of three different perchlorate salt solutions. The methanogens tested were Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum and Methanococcus maripaludis. Media were prepared containing 0%, 0.5%, 1.0%, 2%, 5% and 10% wt/vol magnesium perchlorate, sodium perchlorate, or calcium perchlorate. Organisms were inoculated into their respective media followed by incubation at each organism's growth temperature. Methane production, commonly used to measure methanogen growth, was measured by gas chromatography of headspace gas samples. Methane concentrations varied with species and perchlorate salt tested. However, all four methanogens produced substantial levels of methane in the presence of up to 1.0% perchlorate, but not higher. The standard procedure for growing methanogens typically includes sodium sulfide, a reducing agent, to reduce residual molecular oxygen. However, the sodium sulfide may have been reducing the perchlorate, thus allowing for growth of the methanogens. To investigate this possibility, experiments were conducted where stainless steel nails were used instead of sodium sulfide as the reducing agent. Prior to the addition of perchlorate and inoculation, the nails were removed from the liquid medium. Just as in the prior experiments, the methanogens produced methane at comparable levels to those seen with sodium sulfide as the reductant, indicating that sodium sulfide did not reduce the perchlorate to any significant extent. Additionally, cells metabolizing in 1% perchlorate were transferred to 2%, cells metabolizing in 2% were transferred to 5%, and finally cells metabolizing in 5% were transferred to 10%. All four species produced methane at 2% and 5%, but not 10

  7. Isotopic mapping of groundwater perchlorate plumes.

    Science.gov (United States)

    Sturchio, Neil C; Hoaglund, John R; Marroquin, Roy J; Beloso, Abelardo D; Heraty, Linnea J; Bortz, Sarah E; Patterson, Thomas L

    2012-01-01

    Analyses of stable isotope ratios of chlorine and oxygen in perchlorate can, in some cases, be used for mapping and source identification of groundwater perchlorate plumes. This is demonstrated here for large, intersecting perchlorate plumes in groundwater from a region having extensive groundwater perchlorate contamination and a large population dependent on groundwater resources. The region contains both synthetic perchlorate derived from rocket fuel manufacturing and testing activities and agricultural perchlorate derived predominantly from imported Chilean (Atacama) nitrate fertilizer, along with a likely component of indigenous natural background perchlorate from local wet and dry atmospheric deposition. Most samples within each plume reflect either a predominantly synthetic or a predominantly agricultural perchlorate source and there is apparently a minor contribution from the indigenous natural background perchlorate. The existence of isotopically distinct perchlorate plumes in this area is consistent with other lines of evidence, including groundwater levels and flow paths as well as the historical land use and areal distribution of potential perchlorate sources. PMID:21352209

  8. 2-(Benzenesulfonamidopyridinium perchlorate

    Directory of Open Access Journals (Sweden)

    Xun Li

    2009-06-01

    Full Text Available In the title compound, C11H11N2O2S+·ClO4−, the dihedral angle between the benzene and pyridinium rings is 87.33 (10°. An intramolecular N—H...O interaction, with an S=O-bonded O atom as receptor, occurs in the cation. In the crystal structure, ion pairs occur, being linked by strong N—H...O hydrogen bonds. The perchlorate anion plays a further role in the molecular packing by accepting several weak C—H...O interactions.

  9. Effect of nitrate on microbial perchlorate reduction

    Science.gov (United States)

    Sun, Y.; Coates, J. D.

    2007-12-01

    Over the last decade perchlorate has been recognized as an important emerging water contaminant that poses a significant public health threat. Because of its chemical stability, low ionic charge density, and significant water solubility microbial remediation has been identified as the most feasible method for its in situ attenuation. Our previous studies have demonstrated that dissimilatory perchlorate reducing bacteria (DPRB) capable of the respiratory reduction of perchlorate into innocuous chloride are ubiquitous in soil and sedimentary environments. As part of their metabolism these organisms reduce perchlorate to chlorite which is subsequently dismutated into chloride and molecular oxygen. These initial steps are mediated by the perchlorate reductase and chlorite dismutase enzymes respectively. Previously we found that the activity of these organisms is dependent on the presence of molybdenum and is inhibited by the presence of oxygen and to different extents nitrate. However, to date, there is little understanding of the mechanisms involved in the regulation of perchlorate reduction by oxygen and nitrate. As a continuation of our studies into the factors that control DPRB activity we investigated these regulatory mechanisms in more detail as a model organism, Dechloromonas aromatica strain RCB, transitions from aerobic metabolism through nitrate reduction to perchlorate reduction. In series of growth transition studies where both nitrate and perchlorate were present, preference for nitrate to perchlorate was observed regardless of the nitrate to perchlorate ratio. Even when the organism was pre-grown anaerobically in perchlorate, nitrate was reduced prior to perchlorate. Using non-growth washed cell suspension, perchlorate- grown D. aromatica was capable of reducing both perchlorate and nitrate concomitantly suggesting the preferentially utilization of nitrate was not a result of enzyme functionality. To elucidate the mechanism for preferential utilization of

  10. Peptide biomarkers as evidence of perchlorate biodegradation.

    Science.gov (United States)

    Bansal, Reema; Crawford, Ronald L; Paszczynski, Andrzej J

    2011-02-01

    Perchlorate is a known health hazard for humans, fish, and other species. Therefore, it is important to assess the response of an ecosystem exposed to perchlorate contamination. The data reported here show that a liquid chromatography-mass spectrometry-based proteomics approach for the detection of perchlorate-reducing enzymes can be used to measure the ability of microorganisms to degrade perchlorate, including determining the current perchlorate degradation status. Signature peptides derived from chlorite dismutase (CD) and perchlorate reductase can be used as biomarkers of perchlorate presence and biodegradation. Four peptides each derived from CD and perchlorate reductase subunit A (PcrA) and seven peptides derived from perchlorate reductase subunit B (PcrB) were identified as signature biomarkers for perchlorate degradation, as these sequences are conserved in the majority of the pure and mixed perchlorate-degrading microbial cultures examined. However, chlorite dismutase signature biomarker peptides from Dechloromonas agitata CKB were found to be different from those in other cultures used and should also be included with selected CD biomarkers. The combination of these peptides derived from the two enzymes represents a promising perchlorate presence/biodegradation biomarker system. The biomarker peptides were detected at perchlorate concentrations as low as 0.1 mM and at different time points both in pure cultures and within perchlorate-reducing environmental enrichment consortia. The peptide biomarkers were also detected in the simultaneous presence of perchlorate and an alternate electron acceptor, nitrate. We believe that this technique can be useful for monitoring bioremediation processes for other anthropogenic environmental contaminants with known metabolic pathways. PMID:21115710

  11. Organic carbon biostimulates rapid rhizodegradation of perchlorate.

    Science.gov (United States)

    Yifru, Dawit D; Nzengung, Valentine A

    2008-12-01

    Previous hydroponics and field studies identified phytodegradation and rhizodegradation as the two main mechanisms by which plants metabolize perchlorate. Plant uptake and phytodegradation of perchlorate is a slower and undesired process that poses ecological risks resulting from phytoaccumulation of some fraction of the perchlorate. Meanwhile, rhizodegradation is a more rapid and favored process involving perchlorate-degrading bacteria utilizing dissolved organic carbon (DOC) as a carbon and energy (electron) source to rapidly degrade perchlorate to innocuous chloride. In the present study, rhizodegradation of perchlorate by willow trees (Salix nigra) was biostimulated using electron sources obtained from natural and artificial carbon sources. In bioreactors provided with carbon sources as 500 mg/L DOC, 25 to 40 mg/L of initial perchlorate concentrations were removed to below the ion chromatography method detection limit of 2 microg/L in approximately 9 d. For planted controls provided with no electron donors, the time required for the complete removal of the same doses of perchlorate was up to 70 d. Enhancement of rhizodegradation by organic carbon reduced the phytoaccumulated fraction of perchlorate by an order of magnitude from approximately 430 to 20 mg/kg. The implication of the present study is that the high fraction uptake and phytoaccumulation of perchlorate in agricultural products and the recycling of perchlorate into the ecosystem can be significantly curtailed by supplying electron donors derived from organic carbon sources to the root zone of plants. PMID:18593217

  12. Perchlorate Removal in groundwater by perchlorate reductases from the perchlorate respiring bacterium, perc1ace

    OpenAIRE

    Frankenberger, William

    2003-01-01

    [Note: See PDF for correct symbols.] Perchlorate (ClO4-) is an important energetic component of solid rocket fuel. The major source of ClO4- pollution is the military, space program and supporting industries. ClO4- is recalcitrant in the environment and is potentially toxic. The California Department of Health Services adopted an action level of 4 ppb for perchlorate in potable water. Microorganisms that reduce ClO4- to chloride and molecular oxygen have been isolated. For designing an effici...

  13. PERCHLORATE PHYTOREMEDIATION USING HARDWOOD TREES AND VASCULAR PLANTS

    Science.gov (United States)

    Perchlorate has contaminated water and soils at several locations in the United States. Perchlorate iswater soluble, exceedingly mobile in aqueous systems, and can persist for many decades under typical ground and surface water conditions. Perchlorate is of concern because of...

  14. Perchlorate in the San Antonio Segment of the Edwards Aquifer, Texas

    Science.gov (United States)

    Fahlquist, L.; Rajagapolan, S.; Jackson, W. A.

    2007-12-01

    Perchlorate has been detected in drinking-water supplies and can have adverse health effects on humans by disrupting thyroid function. Perchlorate and other constituents were analyzed from ground-water samples that were collected in 2004-06 from 99 wells completed in the San Antonio segment of the Edwards aquifer as part of the U.S. Geological Survey National Water-Quality Assessment Program. The fractured karstic carbonate Edwards aquifer, declared a sole-source aquifer by the U.S. Environmental Protection Agency, supplies nearly one-half million acre-feet per year for drinking water and other uses. Wells were located in a variety of land-use settings that included rangeland, agriculture, and urban; well types included domestic, public, and observation. Perchlorate was detected in 98 percent of the samples, and concentrations ranged from less than 0.05 to 3 micrograms per liter (μg/L). Five samples contained concentrations greater than 1 μg/L and were from wells in the urban northern San Antonio area. The results from three samples that contained perchlorate at concentrations greater than 2 μg/L are anomalous. Chloride concentration ranged from 5.6 to 69 milligrams per liter, typical for freshwater in the Edwards aquifer. No significant (r2 greater than 0.7) correlations were observed when perchlorate concentrations were correlated with depth to water, total depth of well, or concentrations of bicarbonate, nitrate, phosphate, sulfate, bromide, chloride, fluoride, calcium, magnesium, potassium, sodium, strontium, and dissolved solids. Tritium concentrations ranged from 1.2 to 2.9 tritium units in 31 of the 99 samples and indicate at least some fraction of modern water (post-atmospheric nuclear tests). No correlation between apparent tritium age and perchlorate concentration was observed, a possible indication that anthropogenic influences are not affecting observed perchlorate concentrations. The molar ratio of chloride to perchlorate ranged from 17,000 to 320

  15. PHYTOREMEDIATION OF PERCHLORATE BY TOBACCO PLANTS

    Science.gov (United States)

    Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in the plant tissues. The objective of this research was to determine the effectiveness of tobacco plants in phytoremediation, a technology that employs plants to degrade,...

  16. Peptide Biomarkers as Evidence of Perchlorate Biodegradation▿ †

    OpenAIRE

    Bansal, Reema; Crawford, Ronald L.; Paszczynski, Andrzej J.

    2010-01-01

    Perchlorate is a known health hazard for humans, fish, and other species. Therefore, it is important to assess the response of an ecosystem exposed to perchlorate contamination. The data reported here show that a liquid chromatography-mass spectrometry-based proteomics approach for the detection of perchlorate-reducing enzymes can be used to measure the ability of microorganisms to degrade perchlorate, including determining the current perchlorate degradation status. Signature peptides derive...

  17. Perchlorate reduction by microbes inhabiting oil reservoirs

    Science.gov (United States)

    Liebensteiner, Martin; Stams, Alfons; Lomans, Bart

    2014-05-01

    Microbial perchlorate and chlorate reduction is a unique type of anaerobic respiration as during reduction of (per)chlorate chlorite is formed, which is then split into chloride and molecular oxygen. In recent years it was demonstrated that (per)chlorate-reducing bacteria may employ oxygenase-dependent pathways for the degradation of aromatic and aliphatic hydrocarbons. These findings suggested that (per)chlorate may be used as oxygen-releasing compound in anoxic environments that contain hydrocarbons, such as polluted soil sites and oil reservoirs. We started to study perchlorate reduction by microbes possibly inhabiting oil reservoirs. One of the organisms studied was Archaeoglobus fulgidus. This extremely thermophilic archaeon is known as a major contributor to souring in hot oil reservoirs. A. fulgidus turned out to be able to use perchlorate as terminal electron acceptor for growth with lactate (Liebensteiner et al 2013). Genome based physiological experiments indicated that A. fulgidus possesses a novel perchlorate reduction pathway. Perchlorate is first reduced to chlorite, but chlorite is not split into chloride and molecular oxygen as occurs in bacteria. Rather, chlorite reacts chemically with sulfide, forming oxidized sulfur compounds, which are reduced to sulfide in the electron transport chain by the archaeon. The dependence of perchlorate reduction on sulfur compounds could be shown. The implications of our findings as novel strategy for microbiological enhanced oil recovery and for souring mitigation are discussed. Liebensteiner MG, Pinkse MWH, Schaap PJ, Stams AJM and Lomans BP (2013) Archaeal (per)chlorate reduction at high temperature, a matter of abiotic-biotic reactions. Science 340: 85-87

  18. Electric conductivity of gel-polymeric electrolytes with Ca, Mg and Zn perchlorate salts

    OpenAIRE

    NIKOLA CVJETICANIN; SLAVKO MENTUS

    1999-01-01

    The gel-polymeric electrolytes were prepared with calcium, magnesium and zinc perchlorates dissolved in propylene carbonate together with poly (acrylo nitrile) or poly(methyl methacrylate) as a solution immobilizing polymers. The electric conductivity of these electrolytes was examined in the dependence of temperature and solvent content, at a constant salt-to-polymer concentration ratio. The electrolyte compositions were outlined having the conductivity close to 10-3 S cm-1. It was demonstra...

  19. A Colorimetric Bioassay for Perchlorate

    Science.gov (United States)

    Heinnickel, M. L.; Smith, S.; Coates, J. D.

    2007-12-01

    Recognition of perchlorate (ClO4-) as a widespread contaminant across the United States and its potential adverse affects towards human health has motivated the EPA to place ClO4- on its contaminant candidate list for drinking water supplies. While a federal MCL has not yet been set, a recommended public health goal of 1 ppb (μg.L-1) was established by the US EPA in 2002. To date, methods of detection require use of sensitive ion chromatographic equipment that are expensive, time consuming, and require highly trained personnel for use. Our studies are focused on the development of a highly sensitive, simple, and robust colorimetric bioassay based on the primary enzyme involved in microbial ClO4- reduction, the perchlorate reductase (Pcr). A previously published assay used reduced methyl viologen (MV, the dye is reduced with sodium hydrosulfite) as an electron donor to demonstrate Pcr activity. The assay directly correlates the amount of MV oxidized with the amount of ClO4- reduced by assuming a transfer of four electrons. To test this assumption, we compared actual concentrations of MV oxidized to ClO4- reduced in this assay. ClO4- concentrations were determined using a Dionex ICS-500 ion chromatography system, while MV concentrations were determined using a standard curve generated at 578 nm. Comparisons between the two revealed that twelve molecules of MV were oxidized for each molecule of ClO4- reduced. The oxidation of these additional eight MV molecules is explained by the interaction of the dye with chlorite (the product of the Pcr reaction) and other contaminants that could be present in the enzyme prep. This unsettling result indicated this assay would be problematic for the detection of ClO4- in soil, which has many chemicals that could react with MV. To improve upon this assay, we have tried to reduce ClO4- using less reactive dyes and reductants. The reductants ascorbic acid, NADH, and dithiothreitol drive Pcr catalyzed ClO4- reduction, however, they

  20. The Microbiology of Perchlorate in the Environment

    Science.gov (United States)

    Coates, J. D.

    2007-12-01

    In the last decade perchlorate has been identified as an important groundwater component that poses potential health threat. Although primarily sourced anthropogenically, many recent studies have identified significant natural pools throughout the US and the natural mechanisms of its synthesis remain a mystery. As such, the true perchlorate concentrations naturally present in the environment are still unknown making its regulation problematic. Because of its solubility and non-reactivity the fate and transport of perchlorate in the environment is primarily a function of microbial activity. In the last seven years more than forty specialized perchlorate respiring organisms have been identified and characterized. These dissimilatory perchlorate reducing bacteria (DPRB) are metabolically diverse and environmental populations tend to be dominated by two primary genotypes, the Dechloromonas and the Azospira species. As such, the majority of our understanding of this metabolism is based on these organisms. These organisms are readily found in soil and sedimentary environments and often associate with the rhizosphere. Recent research has demonstrated an accumulation of these organisms along plant roots suggesting their catabolism of root exudates and molecular studies has demonstrated their existence as endophytic infections of the stem and leaves of actively growing Brachypodium grass plants although their exact role under these conditions is unknown. These microorganisms are generally not nutritionally fastidious and vitamin supplementation is unnecessary for growth although molybdenum is a required trace element for perchlorate reduction. The Dechloromonas and Azospira species generally grow optimally at pH values near neutrality in freshwater environments. Even so, recent field studies have shown that related deep-branching members of these genera often predominate in sites of adverse pH or salinity with some species being capable of growth and perchlorate respiration

  1. Silver(I) imidazole perchlorate

    International Nuclear Information System (INIS)

    The crystal structure of silver(I) imidazole perchlorate reveals the presence of a planar (Ag+)6 cluster, in which three radiating pairs of Ag+ ions 3.051(1) A apart are disposed on the corners of an equilateral triangle, the inner Ag+ ions being 3.493(1) A apart. Each silver ion carries two linearly co-ordinated imidazole ligands, the whole unit has 32 (D3) symmetry. Exposure to 60Co γ-rays at 77 K results in electron addition to a group of three equivalent silver atoms. The 109Ag, 107Ag, and 14N hyperfine coupling constants show that the total 5s character of the unpaired electron is only ca. 0.55, and delocalisation onto six equivalent nitrogen ligands accounts for ca. 0.25. Low g values suggest that the remaining spin density is in 5p orbitals on silver. There is no indication of delocalisation onto the remaining three Ag+ ions in the cluster. Possible reasons for this selectivity are discussed. The electron-loss centre appears to be a normal Ag2+ complex. It is suggested that marked distortion results in the hole being trapped on one silver rather than being delocalised. (author)

  2. Perchlorate in The Great Lakes: Isotopic Composition and Origin

    OpenAIRE

    Poghosyan, Armen; Sturchio, Neil C.; Morrison, Candice G.; Beloso, Abelardo D., Jr.; Guan, Yunbin; Eiler, John M.; Jackson, W. Andrew; Hatzinger, Paul B.

    2014-01-01

    Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (δ^(18)O, Δ^(17)O) and chlorine (δ^(37)Cl) along with the abundance of the radioactive isotope ^(36)Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0....

  3. Identification, Characterization, and Classification of Genes Encoding Perchlorate Reductase

    OpenAIRE

    Bender, Kelly S.; Shang, Ching; Chakraborty, Romy; Belchik, Sara M.; Coates, John D.; Achenbach, Laurie A.

    2005-01-01

    The reduction of perchlorate to chlorite, the first enzymatic step in the bacterial reduction of perchlorate, is catalyzed by perchlorate reductase. The genes encoding perchlorate reductase (pcrABCD) in two Dechloromonas species were characterized. Sequence analysis of the pcrAB gene products revealed similarity to α- and β-subunits of microbial nitrate reductase, selenate reductase, dimethyl sulfide dehydrogenase, ethylbenzene dehydrogenase, and chlorate reductase, all of which are type II m...

  4. Environmental biotechnology and microbiology of (per)chlorate reducing bacteria

    NARCIS (Netherlands)

    Mehboob, F.; Schraa, G.; Stams, A.J.M.

    2011-01-01

    Perchlorates are the salts derived from perchloric acid (HClO4). They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders and are used extensively within the pyrotechnics industry, and ammonium perchlorate is also

  5. Quantitative Detection of Perchlorate-Reducing Bacteria by Real-Time PCR Targeting the Perchlorate Reductase Gene▿

    OpenAIRE

    Nozawa-Inoue, Mamie; Jien, Mercy; Hamilton, Nicholas S.; Stewart, Valley; Scow, Kate M.; Hristova, Krassimira R.

    2008-01-01

    A quantitative real-time PCR assay targeting the pcrA gene, encoding the catalytic subunit of perchlorate reductase, detected pcrA genes from perchlorate-reducing bacteria in three different genera and from soil microbial communities. Partial pcrA sequences indicated differences in the composition of perchlorate-reducing bacterial communities following exposure to different electron donors.

  6. Quantitative detection of perchlorate-reducing bacteria by real-time PCR targeting the perchlorate reductase gene.

    Science.gov (United States)

    Nozawa-Inoue, Mamie; Jien, Mercy; Hamilton, Nicholas S; Stewart, Valley; Scow, Kate M; Hristova, Krassimira R

    2008-03-01

    A quantitative real-time PCR assay targeting the pcrA gene, encoding the catalytic subunit of perchlorate reductase, detected pcrA genes from perchlorate-reducing bacteria in three different genera and from soil microbial communities. Partial pcrA sequences indicated differences in the composition of perchlorate-reducing bacterial communities following exposure to different electron donors. PMID:18245250

  7. Perchlorate levels in soil and waters from the Atacama Desert.

    Science.gov (United States)

    Calderón, R; Palma, P; Parker, D; Molina, M; Godoy, F A; Escudey, M

    2014-02-01

    Perchlorate is an anion that originates as a contaminant in ground and surface waters. The presence of perchlorate in soil and water samples from northern Chile (Atacama Desert) was investigated by ion chromatography-electrospray mass spectrometry. Results indicated that perchlorate was found in five of seven soils (cultivated and uncultivated) ranging from 290 ± 1 to 2,565 ± 2 μg/kg. The greatest concentration of perchlorate was detected in Humberstone soil (2,565 ± 2 μg/kg) associated with nitrate deposits. Perchlorate levels in Chilean soils are greater than those reported for uncultivated soils in the United States. Perchlorate was also found in superficial running water ranging from 744 ± 0.01 to 1,480 ± 0.02 μg/L. Perchlorate water concentration is 30-60 times greater than levels established by the United States Environmental Protection Agency (24.5 μg/L) for drinking. PMID:24165784

  8. Atmospheric origins of perchlorate on Mars and in the Atacama

    Science.gov (United States)

    Catling, D. C.; Claire, M. W.; Zahnle, K. J.; Quinn, R. C.; Clark, B. C.; Hecht, M. H.; Kounaves, S.

    2010-01-01

    Isotopic studies indicate that natural perchlorate is produced on Earth in arid environments by the oxidation of chlorine species through pathways involving ozone or its photochemical products. With this analogy, we propose that the arid environment on Mars may have given rise to perchlorate through the action of atmospheric oxidants. A variety of hypothetical pathways can be proposed including photochemical reactions, electrostatic discharge, and gas-solid reactions. Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site, we made a preliminary study of the means to produce Atacama perchlorate to help shed light on the origin of Martian perchlorate. We investigated gas phase pathways using a 1-D photochemical model. We found that perchlorate can be produced in sufficient quantities to explain the abundance of perchlorate in the Atacama from a proposed gas phase oxidation of chlorine volatiles to perchloric acid. The feasibility of gas phase production for the Atacama provides justification for future investigations of gas phase photochemistry as a possible source for Martian perchlorate.

  9. Plant-mediated transformation of perchlorate into chloride

    Energy Technology Data Exchange (ETDEWEB)

    Nzengung, V.A.; Wang, C. [Univ. of Georgia, Athens, GA (United States). Dept. of Geology; Harvey, G. [AEM, Wright Patterson AFB, OH (United States)

    1999-05-01

    The decontamination of perchlorate-contaminated water by woody plants was investigated in sand and hydroponic bioreactors. Willow trees were found to be the most favorable woody plants with phraetophytic characteristics in comparative screen tests with eastern cottonwoods and Eucalyptus cineria. Willows decontaminated aqueous solutions dosed with 10--100 mg/.L of perchlorate to below the method detection limit of 2 {micro}g/L. Two phytoprocesses were identified as important in the remediation of perchlorate-contaminated water: (1) uptake and phytodegradation of perchlorate in the tree branches and leaves and (2) rhizodegradation. Exposure of rooted willow trees to perchlorate-dosed media stimulated rhizodegradation. Homogeneous degradation studies using media from the root zone of dosed willow trees confirmed that rhizosphere-associated microorganisms mediated the degradation of perchlorate to chloride. Experiments conducted with varying ranges of nitrate concentrations clearly indicated that high nitrate concentrations interfered with rhizodegradation of perchlorate. This study provides evidence that the efficacy of phytoremediation of perchlorate-contaminated environments may depend on the concentration of competing terminal electron acceptors, such as nitrate, and the nitrogen source of the nutrient solution., Since perchlorate does not volatilize from water readily, a perchlorate remediation scheme may involve an intensively cultivated plantation of trees with phraetophytic characteristics and irrigation with the contaminated water.

  10. Perchlorate induced low temperature carbonate decomposition in the Mars Phoenix Thermal and Evolved Gas Analyzer (TEGA)

    Science.gov (United States)

    Cannon, K. M.; Sutter, B.; Ming, D. W.; Boynton, W. V.; Quinn, R.

    2012-07-01

    Simulated Thermal Evolved Gas Analyzer (TEGA) analyses have shown that a CO2 release detected between 400°C and 680°C by the Phoenix Lander's TEGA instrument may have been caused by a reaction between calcium carbonate and hydrated magnesium perchlorate. In our experiments a CO2 release beginning at 385 ± 12°C was attributed to calcite reacting with water vapor and HCl gas from the dehydration and thermal decomposition of Mg-perchlorate. The release of CO2 is consistent with the TEGA detection of CO2 released between 400 and 680°C, with the amount of CO2 increasing linearly with added perchlorate. X-ray diffraction (XRD) experiments confirmed CaCl2 formation from the reaction between calcite and HCl. These results have important implications for the Mars Science Laboratory (MSL) Curiosity rover. Heating soils may cause inorganic release of CO2; therefore, detection of organic fragments, not CO2 alone, should be used as definitive evidence for organics in Martian soils.

  11. Perchlorate Exposure and Thyroid Function in Ammonium Perchlorate Workers in Yicheng, China

    Directory of Open Access Journals (Sweden)

    Hongxia Chen

    2014-05-01

    Full Text Available The impact of low level dust on the thyroid function of workers chronically exposed to ammonium perchlorate (AP is uncertain and controversial. The aim of this study was to examine whether workers in China with long-term (>3 years occupational exposure to low levels of AP dust had affected thyroid homeostasis. Mean occupational exposures to AP dust ranged from 0.43 to 1.17 mg/m3. Geometric means of post-shift urinary perchlorate levels were 20.5 µg/L for those exposed and 12.8 µg/L for the controls. No significant differences were found for thyroid function parameters of FT3, FT4, or log TSH or for TPO prevalence or thyroglobulin levels. Additionally, no differences in findings were observed for complete blood count (CBC, serum biochemical profile, or pulmonary function test. Median urinary iodine levels of 172 and 184 µg/L showed that the workers had sufficient iodine intake. This study found no effect on thyroid function from long term, low-level documented exposure to ammonium perchlorate. It is the first study to report both thyroid status parameters and urinary perchlorate, a biomarker of internal perchlorate exposure, in occupationally exposed workers in China.

  12. ACCUMULATION OF PERCHLORATE IN TOBACCO PLANTS: DEVELOPMENT OF A PLANT KINETIC MODEL

    Science.gov (United States)

    Previous studies have shown that tobacco plants are tolerant of perchlorate and will accumulate perchlorate in plant tissues. This research determined the uptake, translocation, and accumulation of perchlorate in tobacco plants. Three hydroponics growth studies were completed u...

  13. Different Strategies for Biological Remediation of Perchlorate Contaminated Groundwater

    OpenAIRE

    Wang, Yue

    2012-01-01

    Perchlorate (ClO4-) has gained attention recently due to its interference with thyroid gland function. In infants and unborn children, inadequate thyroid hormone production can cause mental retardation and thyroid tumors. Since new perchlorate standards will be proposed in 2013, and if a stricter standard is imposed, cost effective technologies will be in high demand. The overall objective of this research was to evaluate two perchlorate bioremediation strategies using indigenous soil bact...

  14. Perchlorate and nitrate in leafy vegetables of North America.

    Science.gov (United States)

    Sanchez, C A; Crump, K S; Krieger, R I; Khandaker, N R; Gibbs, J P

    2005-12-15

    In previous studies trace levels of perchlorate were found in lettuce (Lactuca sativa L.) irrigated with Colorado River water, which is contaminated with low levels of perchlorate from aerospace and defense related industries. In this paper, we report the results of a survey conducted across North America to evaluate the occurrence of perchlorate in leafy vegetables produced outside the lower Colorado River region, and evaluate the relative iodide uptake inhibition potential to perchlorate and nitrate in these leafy vegetables. Conventionally and organically produced lettuce and other leafy vegetable samples were collected from production fields and farmers' markets in the central and coastal valleys of California, New Mexico, Colorado, Michigan, Ohio, New York, Quebec, and New Jersey. Results show that 16% of the conventionally produced samples and 32% of the organically produced samples had quantifiable levels of perchlorate using ion chromatography. Estimated perchlorate exposure from organically produced leafy vegetables was approximately 2 times that of conventional produce, but generally less than 10% of the reference dose recommended by the National Academy of Sciences. Furthermore, the iodide uptake inhibition potential of perchlorate was less than 1% of that of the nitrate present. These data are consistent with those of other reported perchlorate survey work with lettuce, bottled water, breast milk, dairy milk, and human urine, and suggest a wide national presence of perchlorate. PMID:16475313

  15. Atmospheric Production of Perchlorate on Earth and Mars

    Science.gov (United States)

    Claire, M.; Catling, D. C.; Zahnle, K. J.

    2009-12-01

    Natural production and preservation of perchlorate on Earth occurs only in arid environments. Isotopic evidence suggests a strong role for atmospheric oxidation of chlorine species via pathways including ozone or its photochemical derivatives. As the Martian atmosphere is both oxidizing and drier than the driest places on Earth, we propose an atmospheric origin for the Martian perchlorates measured by NASA's Phoenix Lander. A variety of hypothetical formation pathways can be proposed including atmospheric photochemical reactions, electrostatic discharge, and gas-solid reactions. Here, we investigate gas phase formation pathways using a 1-D photochemical model (Catling et al. 2009, accepted by JGR). Because perchlorate-rich deposits in the Atacama desert are closest in abundance to perchlorate measured at NASA's Phoenix Lander site, we start with a study of the means to produce Atacama perchlorate. We found that perchlorate can be produced in sufficient quantities to explain the abundance of perchlorate in the Atacama from a proposed gas phase oxidation of chlorine volatiles to perchloric acid. These results are sensitive to estimated reaction rates for ClO3 species. The feasibility of gas phase production for the Atacama provides justification for further investigations of gas phase photochemistry as a possible source for Martian perchlorate. In addition to the Atacama results, we will present a preliminary study incorporating chlorine chemistry into an existing Martian photochemical model (Zahnle et al. JGR 2008).

  16. Interaction of perchlorate and trichloroethene bioreductions in mixed anaerobic culture.

    Science.gov (United States)

    Wen, Li-Lian; Yang, Qiang; Zhang, Zhao-Xin; Yi, Yang-Yi; Tang, Youneng; Zhao, He-Ping

    2016-11-15

    This work evaluated the interaction of perchlorate and trichloroethene (TCE), two common co-contaminants in groundwater, during bioreduction in serum bottles containing synthetic mineral salts media and microbial consortia. TCE at concentrations up to 0.3mM did not significantly affect perchlorate reduction; however, perchlorate concentrations higher than 0.1mM made the reduction of TCE significantly slower. Perchlorate primarily inhibited the reduction of vinyl chloride (VC, a daughter product of TCE) to ethene. Mechanistic analysis showed that the inhibition was mainly because perchlorate reduction is thermodynamically more favorable than reduction of TCE and its daughter products and not because of toxicity due to accumulation of dissolved oxygen produced during perchlorate reduction. As the initial perchlorate concentration increased from 0 to 600mg/L in a set of serum bottles, the relative abundance of Rhodocyclaceae (a putatively perchlorate-reducing genus) increased from 6.3 to 80.6%, while the relative abundance of Dehalococcoides, the only known genus that is able to reduce TCE all the way to ethene, significantly decreased. Similarly, the relative abundance of Proteobacteria (a phylum to which most known perchlorate-reducing bacteria belong) increased from 22% to almost 80%. PMID:27449607

  17. Perchlorate in the Great Lakes: isotopic composition and origin.

    Science.gov (United States)

    Poghosyan, Armen; Sturchio, Neil C; Morrison, Candice G; Beloso, Abelardo D; Guan, Yunbin; Eiler, John M; Jackson, W Andrew; Hatzinger, Paul B

    2014-10-01

    Perchlorate is a persistent and mobile contaminant in the environment with both natural and anthropogenic sources. Stable isotope ratios of oxygen (δ(18)O, Δ(17)O) and chlorine (δ(37)Cl) along with the abundance of the radioactive isotope (36)Cl were used to trace perchlorate sources and behavior in the Laurentian Great Lakes. These lakes were selected for study as a likely repository of recent atmospheric perchlorate deposition. Perchlorate concentrations in the Great Lakes range from 0.05 to 0.13 μg per liter. δ(37)Cl values of perchlorate from the Great Lakes range from +3.0‰ (Lake Ontario) to +4.0‰ (Lake Superior), whereas δ(18)O values range from -4.1‰ (Lake Superior) to +4.0‰ (Lake Erie). Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ(17)O values (+1.6‰ to +2.7‰) divided into two distinct groups: Lake Superior (+2.7‰) and the other four lakes (∼+1.7‰). The stable isotopic results indicate that perchlorate in the Great Lakes is dominantly of natural origin, having isotopic composition resembling that measured for indigenous perchlorate from preindustrial groundwaters of the western USA. The (36)Cl/Cl ratio of perchlorate varies widely from 7.4 × 10(-12) (Lake Ontario) to 6.7 × 10(-11) (Lake Superior). These (36)ClO4(-) abundances are consistent with an atmospheric origin of perchlorate in the Great Lakes. The relatively high (36)ClO4(-) abundances in the larger lakes (Lakes Superior and Michigan) could be explained by the presence of (36)Cl-enriched perchlorate deposited during the period of elevated atmospheric (36)Cl activity following thermonuclear bomb tests in the Pacific Ocean. PMID:25171443

  18. High ozone increases soil perchlorate but does not affect foliar perchlorate content

    Science.gov (United States)

    Ozone (O3) is implicated in the natural source inventory of perchlorate (ClO4-), a hydrophilic salt that migrates to ground water and interferes with uptake of iodide in mammals, including humans. Tropospheric O3 is elevated in many areas. We previously showed (Grantz et al., 2013; Environmental Pol...

  19. PERCHLORATE IDENTIFICATION IN FERTILIZERS AND ACCUMULATION IN LETTUCE SEEDLINGS

    Science.gov (United States)

    Perchlorate has contaminated groundwater, drinking water and soils at several locations in the U.S. The primary source of contamination at sites that have been investigated to date seems to be from industrial and military operations that use Perchlorate as an oxidizing agent. How...

  20. Thermal decomposition of ammonium perchlorate during gamma-ray irradiation

    International Nuclear Information System (INIS)

    To assess radiation damage effects in propellants, pyrotechnics, and similar materials, thermal decomposition measurements were made on ammonium perchlorate powders and crystals during gamma-ray irradiation. Gas evolution studies were made on single crystals and powders of ammonium perchlorate, both at room temperature and at 2270C. The results are discussed. (U.S.)

  1. Bioremediation Potential of Perchlorate Contaminated Deep Vadose Zone

    Science.gov (United States)

    Gal, H.; Ronen, Z.; Weisbrod, N.; Dahan, O.; Nativ, R.

    2007-12-01

    Widespread perchlorate contamination was found in the vadose zone near a plant that manufactures ammonium perchlorate above the coastal aquifer of Israel in Ramat Hasharon. As part of the plant's operations, untreated industrial wastewater was disposed of for over 30 years in unlined wastewater ponds and nearby washes, causing contamination of the unsaturated zone (up to 2200 mg kg-1 sediment at a depth of 20 m) and the groundwater below it (up to 300 mg L-1). In this study, we examined the potential for microbial metabolism of perchlorate reduction in the contaminated deep vadose zone profile by native microbial communities. Microbial reduction of perchlorate was found in three of the four sediment samples taken from different depths. The sediments taken from 1 m (shallowest) and 35 m (deepest- close to the water table) showed the fastest degradation rates, while the sediment taken from 15 m showed the slowest rate. No perchlorate reduction was observed in the sediment taken from 20 m, where perchlorate concentrations were highest. These results were correlated to the viable microorganism counts in the profile. In experiments in which the effect of nitrate was examined, the lag time for perchlorate degradation was found to be inversely correlated to the initial nitrate concentration, while the perchlorate-reduction rates were faster in treatments with higher initial nitrate concentrations. We found no perchlorate degradation as long as nitrate was present in the system: perchlorate reduction was initiated only after all of the nitrate had been reduced. Nitrate-reduction rates were correlated to the initial nitrate concentrations and no lag period was observed. Nitrite was temporarily accumulated during nitrate reduction and was totally reduced, like nitrate, after 4 days. Count of viable microbial communities as well as PCR analysis of the chlorite dismutase gene in the native microbial population exposed to high concentrations of perchlorate (10,000-20,000 mg L-1

  2. Experimental chlorine stable isotope fractionation of perchlorate respiring bacteria

    Science.gov (United States)

    Ader, M.; Coleman, M.; Coates, J.; Chaudhuri, S.

    2006-12-01

    Perchlorate natural occurrences on earth are very limited and seem restricted to extremely arid environments such as nitrate deposits of the Atacama Desert of northern Chile, where perchlorate contents can reach 0.1 to 1%. Anthropogenically sourced perchlorate however is extensively used as a major component of explosives and rocket fuels. Careless disposal of these highly soluble and very stable perchlorates locally led to the contamination of drinking water, now recognised as posing a significant health threat. Recent studies have demonstrated that some microorganisms are able to completely reduce perchlorate to innocuous chloride, and offer a great potential for the bioremediation of contaminated waters. Provided that the isotopic fractionation associated with this reduction is significant, the measurement of the chloride isotopic composition of contaminated water is a powerful tool for monitoring the progress of in-situ remediation. We report here, the characterisation of the isotopic fractionation associated with perchlorate reduction performed by Dechlorosoma suillum strain PS during 3 culture experiments performed in a batch fermentor (anoxic, 37°°C, pH =7). The basal medium contained acetate as the electron donor and perchlorate as the electron acceptor. When possible, chloride salts were replaced by sulphate salts so as to lower the initial chloride content. The paired chlorine isotopic compositions of chloride and perchlorate in solutions sampled throughout the experiment were measured using the method described in Ader et al. 2001. The fractionation between chloride and perchlorate was calculated independently for each sample, using on the one hand the chloride content and isotopic composition and on the other hand the perchlorate content and isotopic composition. The results show that the fractionation is constant within error throughout the experiment for the 3 experiments with a weighted mean of -14.94±0.14‰. This value is much lower than the

  3. Proteomic detection of proteins involved in perchlorate and chlorate metabolism.

    Science.gov (United States)

    Bansal, Reema; Deobald, Lee A; Crawford, Ronald L; Paszczynski, Andrzej J

    2009-09-01

    Mass spectrometry and a time-course cell lysis method were used to study proteins involved in perchlorate and chlorate metabolism in pure bacterial cultures and environmental samples. The bacterial cultures used included Dechlorosoma sp. KJ, Dechloromonas hortensis, Pseudomonas chloritidismutans ASK-1, and Pseudomonas stutzeri. The environmental samples included an anaerobic sludge enrichment culture from a sewage treatment plant, a sample of a biomass-covered activated carbon matrix from a bioreactor used for treating perchlorate-contaminated drinking water, and a waste water effluent sample from a paper mill. The approach focused on detection of perchlorate (and chlorate) reductase and chlorite dismutase proteins, which are the two central enzymes in the perchlorate (or chlorate) reduction pathways. In addition, acetate-metabolizing enzymes in pure bacterial samples and housekeeping proteins from perchlorate (or chlorate)-reducing microorganisms in environmental samples were also identified. PMID:19199051

  4. Thermal decomposition of beryllium perchlorate tetrahydrate

    International Nuclear Information System (INIS)

    Thermal decomposition of Be(ClO4)2x4H2O was studied by the differential flow technique in the helium stream. The kinetics was followed by an exchange reaction of the perchloric acid appearing by the decomposition with potassium carbonate. The rate of CO2 liberation in this process was recorded by a heat conductivity detector. The exchange reaction yielding CO2 is quantitative, it is not the limiting one and it does not distort the kinetics of the process of perchlorate decomposition. The solid products of decomposition were studied by infrared and NMR spectroscopy, roentgenography, thermography and chemical analysis. A mechanism suggested for the decomposition involves intermediate formation of hydroxyperchlorate: Be(ClO4)2x4H2O → Be(OH)ClO4+HClO4+3H2O; Be(OH)ClO4 → BeO+HClO4. Decomposition is accompained by melting of the sample. The mechanism of decomposition is hydrolytic. At room temperature the hydroxyperchlorate is a thick syrup-like compound crystallizing after long storing

  5. Perchlorates as Powerful Catalysts in Many Important Organic Transformations

    Institute of Scientific and Technical Information of China (English)

    G. Bartoli; L. Sambri; M. Locatelli

    2005-01-01

    @@ 1Introduction For long times, metallic perchlorates have been considered dangerous compounds[1] in that they function as explosives and as incontrollable oxidizers. Therefore, the fear of the great hazard connected with their manufacture and uses had prevented an extensive use both in research laboratories and in industrial processes[2].However, recently it has been cleared that this bad reputation is due to the mistaken association of metallic perchlorates with the oxidizing potential of perchloric acid and the pyrotechnic performances of NH4ClO4.

  6. Effects of Perchlorate on Organic Molecules under Simulated Mars Conditions

    Science.gov (United States)

    Carrier, B. L.; Kounaves, S. P.

    2014-12-01

    Perchlorate (ClO4-) was discovered in the northern polar region of Mars by the Mars Phoenix Lander in 2008 and has also been recently detected by the Curiosity Rover in Gale Crater [1,2]. Perchlorate has also been shown to be formed under current Mars conditions via the oxidation of mineral chlorides, further supporting the theory that perchlorate is present globally on Mars [3]. The discovery of perchlorate on Mars has raised important questions about the effects of perchlorate on the survival and detection of organic molecules. Although it has been shown that pyrolysis in the presence of perchlorate results in the alteration or destruction of organic molecules [4], few studies have been conducted on the potential effects of perchlorate on organic molecules under martian surface conditions. Although perchlorate is typically inert under Mars-typical temperatures [5], perchlorate does absorb high energy UV radiation, and has been shown to decompose to form reactive oxychlorine species such as chlorite (ClO2-) when exposed to martian conditions including UV or ionizing radiation [6,7]. Here we investigate the effects of perchlorate on the organic molecules tryptophan, benzoic acid and mellitic acid in order to determine how perchlorate may alter these compounds under Mars conditions. Experiments are performed in a Mars Simulation Chamber (MSC) capable of reproducing the temperature, pressure, atmospheric composition and UV flux found on Mars. Soil simulants are prepared consisting of SiO2 and each organic, as well as varying concentrations of perchlorate salts, and exposed in the MSC. Subsequent to exposure in the MSC samples are leached and the leachate analyzed by HPLC and LC-MS to determine the degree of degradation of the original organic and the identity of any potential decomposition products formed by oxidation or chlorination. References: [1] Kounaves et al., J. Geophys. Res. Planets, Vol. 115, p. E00E10, 2010 [2] Glavin et al., J. Geophys. Res. Planets, Vol

  7. Simultaneous removal of perchlorate and energetic compounds in munitions wastewater by zero-valent iron and perchlorate-respiring bacteria.

    Science.gov (United States)

    Ahn, Se Chang; Hubbard, Brian; Cha, Daniel K; Kim, Byung J

    2014-01-01

    Ammonium perchlorate is one of the main constituents in Army's insensitive melt-pour explosive, PAX-21 in addition to RDX and 2,4-dinitroanisole (DNAN). The objective of this study is to develop an innovative treatment process to remove both perchlorate and energetic compounds simultaneously from PAX-21 production wastewater. It was hypothesized that the pretreatment of PAX-21 wastewater with zero-valent iron (ZVI) would convert energetic compounds to products that are more amenable for biological oxidation and that these products serve as electron donors for perchlorate-reducing bacteria. Results of batch ZVI reduction experiments showed that DNAN was completely reduced to 2,4-diaminoanisole and RDX was completely reduced to formaldehyde. Anaerobic batch biodegradation experiments showed that perchlorate (30 mg L(-1)) in ZVI-treated PAX-21 wastewater was decreased to an undetectable level after 5 days. Batch biodegradation experiments also confirmed that formaldehyde in ZVI-treated wastewater was the primary electron donor for perchlorate-respiring bacteria. The integrated iron-anaerobic bioreactor system was effective in completely removing energetic compounds and perchlorate from the PAX-21 wastewater without adding an exogenous electron donor. This study demonstrated that ZVI pretreatment not only removed energetic compounds, but also transformed energetic compounds to products that can serve as the source of electrons for perchlorate-respiring bacteria. PMID:24410688

  8. The NAS Perchlorate Review: Adverse Effects?

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Richard B.; Corley, Richard; Cowan, Linda; Utiger, Robert D.

    2005-11-01

    To the editor: Drs. Ginsberg and Rice argue that the reference dose for perchlorate of 0.0007 mg/kg per day recommended by the National Academies’ Committee to Assess the Health Implications of Perchlorate Ingestion is not adequately protective. As members of the committee, we disagree. Ginsberg and Rice base their conclusion on three points. The first involves the designation of the point of departure as a NOEL (no-observed-effect level) versus a LOAEL (lowest-observed-adverse- effect level). The committee chose as its point of departure a dose of perchlorate (0.007 mg/kg per day) that when given for 14 days to 7 normal subjects did not cause a significant decrease in the group mean thyroid iodide uptake (Greer et al. 2002). Accordingly, the committee considered it a NOEL. Ginsberg and Rice focus on the fact that only 7 subjects were given that dose, and they 1seem to say that attention should be paid only to the results in those subjects in whom there was a 1fall in thyroid iodide uptake, and that the results in those in whom there was no fall or an increase should be ignored. They consider the dose to be a LOAEL because of the fall in uptake in those few subjects. It is important to note that a statistically significant decrease of, for example, 5% or even 10%, would not be biologically important and, more important, would not be sustained. For example, in another study (Braverman et al. 2004), administration of 0.04 mg/kg per day to normal subjects for 6 months had no effect on thyroid iodide uptake when measured at 3 and 6 months, and no effect on serum thyroid hormone or thyrotropin concentrations measured monthly (inspection of Figure 5A in the paper by Greer et al. suggests that this dose would inhibit thyroid iodide uptake by about 25% if measured at 2 weeks). The second issue involves database uncertainty. In clinical studies, perchlorate has been administered prospectively to 68 normal subjects for 2 weeks to 6 months. In one study (Brabant et al. 1992

  9. Behavioral response of dissimilatory perchlorate-reducing bacteria to different electron acceptors.

    Science.gov (United States)

    Sun, Yvonne; Gustavson, Ruth L; Ali, Nadia; Weber, Karrie A; Westphal, Lacey L; Coates, John D

    2009-10-01

    The response behavior of three dissimilatory perchlorate-reducing bacteria to different electron acceptors (nitrate, chlorate, and perchlorate) was investigated with two different assays. The observed response was species-specific, dependent on the prior growth conditions, and was inhibited by oxygen. We observed attraction toward nitrate when Dechloromonas aromatica strain RCB and Azospira suillum strain PS were grown with nitrate. When D. aromatica and Dechloromonas agitata strain CKB were grown with perchlorate, both responded to nitrate, chlorate, and perchlorate. When A. suillum was grown with perchlorate, the organism responded to chlorate and perchlorate but not nitrate. A gene replacement mutant in the perchlorate reductase subunit (pcrA) of D. aromatica resulted in a loss of the attraction response toward perchlorate but had no impact on the nitrate response. Washed-cell suspension studies revealed that the perchlorate grown cells of D. aromatica reduced both perchlorate and nitrate, while A. suillum cells reduced perchlorate only. Based on these observations, energy taxis was proposed as the underlying mechanism for the responses to (per)chlorate by D. aromatica. To the best of our knowledge, this study represents the first investigation of the response behavior of perchlorate-reducing bacteria to environmental stimuli. It clearly demonstrates attraction toward chlorine oxyanions and the unique ability of these organisms to distinguish structurally analogous compounds, nitrate, chlorate, and perchlorate and respond accordingly. PMID:19533120

  10. Perchlorate Reductase Is Distinguished by Active Site Aromatic Gate Residues.

    Science.gov (United States)

    Youngblut, Matthew D; Tsai, Chi-Lin; Clark, Iain C; Carlson, Hans K; Maglaqui, Adrian P; Gau-Pan, Phonchien S; Redford, Steven A; Wong, Alan; Tainer, John A; Coates, John D

    2016-04-22

    Perchlorate is an important ion on both Earth and Mars. Perchlorate reductase (PcrAB), a specialized member of the dimethylsulfoxide reductase superfamily, catalyzes the first step of microbial perchlorate respiration, but little is known about the biochemistry, specificity, structure, and mechanism of PcrAB. Here we characterize the biophysics and phylogeny of this enzyme and report the 1.86-Å resolution PcrAB complex crystal structure. Biochemical analysis revealed a relatively high perchlorate affinity (Km = 6 μm) and a characteristic substrate inhibition compared with the highly similar respiratory nitrate reductase NarGHI, which has a relatively much lower affinity for perchlorate (Km = 1.1 mm) and no substrate inhibition. Structural analysis of oxidized and reduced PcrAB with and without the substrate analog SeO3 (2-) bound to the active site identified key residues in the positively charged and funnel-shaped substrate access tunnel that gated substrate entrance and product release while trapping transiently produced chlorate. The structures suggest gating was associated with shifts of a Phe residue between open and closed conformations plus an Asp residue carboxylate shift between monodentate and bidentate coordination to the active site molybdenum atom. Taken together, structural and mutational analyses of gate residues suggest key roles of these gate residues for substrate entrance and product release. Our combined results provide the first detailed structural insight into the mechanism of biological perchlorate reduction, a critical component of the chlorine redox cycle on Earth. PMID:26940877

  11. Determination of Perchlorate in Bottled Water from Italy

    Directory of Open Access Journals (Sweden)

    Patrizia Iannece

    2013-06-01

    Full Text Available Perchlorate is regarded as an emerging persistent inorganic contaminant. It is widely known that perchlorate is an endocrine disruptor as it competitively inhibits iodide transport in the thyroid gland. As drinking water is the major source of human exposure to perchlorate, its occurrence in commercially available bottled waters purchased in different regions of Italy was investigated. Perchlorate was measured using the rapid, sensitive, and selective LC-ESI-MS/MS (liquid chromatography-electrospray tandem mass spectrometry method by multiple reaction monitoring (MRM of the transition 98.8→82.8, which corresponds to the loss of one oxygen atom in the perchlorate ion (ClO4−→ClO3−. The chlorine isotope ratio (35Cl/37Cl was used as a confirmation tool. The limit of quantification (LOQ for this method was 5 ng/L, and the recovery ranged from 94% to 108%. Perchlorate was detected in 44 of the 62 drinking waters tested, with concentrations ranging from <5 to 75 ng/L. These values are similar in magnitude to those reported in drinking water from the USA and do not pose an immediate health concern.

  12. Chemolithotrophic perchlorate reduction linked to the oxidation of elemental sulfur.

    Science.gov (United States)

    Ju, Xiumin; Field, Jim A; Sierra-Alvarez, Reyes; Salazar, Margarita; Bentley, Harold; Bentley, Richard

    2007-04-15

    Perchlorate (ClO(4)(-)) contamination of ground and surface water has been recently recognized as a widespread environmental problem. Biological methods offer promising perspectives of perchlorate remediation. Facultative anaerobic bacteria couple the oxidation of organic and inorganic electron-donating substrates to the reduction of perchlorate as a terminal electron acceptor, converting it completely to the benign end-product, chloride. Insoluble inorganic substrates are of interest for low maintenance bioreactor or permeable reactive barrier systems because they can provide a long-term supply of electron donor without generating organic residuals. The main objective of this research was to investigate the feasibility of utilizing elemental sulfur (S(0)) as an insoluble electron donor for the biological reduction of perchlorate. A chemolithotrophic enrichment culture derived from aerobic activated sludge was obtained which effectively coupled the oxidation of elemental sulfur to sulfate with the reduction of perchlorate to chloride and gained energy from the process for cell growth. The enrichment culture grew at a rate of 0.41 or 0.81 1/d in the absence and presence of added organic carbon for cell growth, respectively. The enrichment culture was also shown to carry out sulfur disproportionation to a limited extent as evidenced by the formation of sulfide and sulfate in the absence of added electron acceptor. When nitrate and perchlorate were added together, the two electron acceptors were removed simultaneously after an initial partial decrease in the nitrate concentration. PMID:17009322

  13. Oxidation of some disubstituted anisole derivatives with ceric perchlorate in perchloric acid solution

    International Nuclear Information System (INIS)

    The influence of concentration of particular reagents on the kinetics of Ce(IV) reduction by 2,6-dimethyl and 3,5-dimethyl-anisole as well as 2-methoxy-5-methyl- and 4-methoxy-2-methyl-aniline in perchloric acid solution was investigated, establishing the stoichiometry of these processes. Some intermediate products - macromolecular, derivatives of p-benzoquinone and 4,4'-diphenoquinone - were separated and identified. The effects of substituents and the conditions of performed oxidation processes on the kind and yields of the resultant products were considered. (author). 22 refs, 1 fig., 1 tab

  14. Perchlorate in The Great Lakes: Distribution, Isotopic Composition and Origin

    Science.gov (United States)

    Poghosyan, A.; Sturchio, N. C.; Jackson, W. A.; Guan, Y.; Eiler, J. M.; Hatzinger, P. B.

    2013-12-01

    Concentrations, stable chlorine and oxygen isotopic compositions, and 36Cl abundances of perchlorate were investigated in the five Laurentian Great Lakes. Samples were collected during monitoring cruises in 2007 and 2008 of the U.S. EPA's RV Lake Guardian and in 2010 at the water supply intake of Marquette, MI on the southern shore of Lake Superior. Concentrations of perchlorate were measured by IC/MS/MS at 24 locations, including one or two depth profiles in each lake. Mean concentrations (μg/L) are: Superior, 0.06 × 0.01; Michigan, 0.10 × 0.01; Huron, 0.11 × 0.01; Erie, 0.08 × 0.01, and Ontario, 0.09 × 0.01. Concentration vs. depth is nearly constant in each lake, indicating well-mixed conditions. Perchlorate was extracted from near-surface water by passing 15,000 to 80,000 L of water through 1-L cartridges containing Purolite A530E bifunctional anion-exchange resin. In the laboratory, perchlorate was eluted from the resin, purified, and precipitated as a >99% pure crystalline phase. Milligram amounts were recovered from each lake. Chlorine and oxygen isotopic analyses were performed at Caltech using the Cameca 7f-GEO SIMS instrument, following validation of the SIMS method with analyses of USGS-37 and USGS-38 isotopic reference materials. Results indicate a relatively narrow range in δ37Cl values (+2.9 to +3.9 ‰) and a wider range in δ18O values (-4.0 to +4.1 ‰), with a general geographic trend of increasing δ18O from west to east. Oxygen-17 was measured at UIC using dual-inlet IRMS of O2 produced by decomposition of KClO4. Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive Δ17O values (+1.6 ‰ to +2.7 ‰) divided into two distinct groups: Lake Superior (+2.7 ‰) and the other four lakes (~ +1.7 ‰). The isotopic data indicate that perchlorate is dominantly of natural origin, having stable isotopic compositions resembling those of perchlorate from pre-industrial groundwaters in the western USA. The 36Cl

  15. Perchlorate, iodine supplements, iodized salt and breast milk iodine content

    International Nuclear Information System (INIS)

    This study was undertaken to determine if increasing maternal iodine intake through single dose tablets will decrease breast milk concentrations of the iodine-uptake inhibitor, perchlorate, through competitive inhibition. We also sought to determine if the timing of supplementation influences the fraction of iodine excreted in milk versus urine and to compare the effectiveness of iodized salt as a means of providing iodine to breastfed infants. Thirteen women who did not use supplements, seven of whom used iodized salt and six of whom used non-iodized salt, submitted four milk samples and a 24-h urine collection daily for three days. Women repeated the sampling protocol for three more days during which ∼ 150 μg of iodine were taken in the evening and again for three days with morning supplementation. Samples were analyzed using isotope-dilution inductively-coupled plasma-mass spectrometry for iodine and isotope-dilution ion chromatography-tandem mass spectrometry for perchlorate. No statistically significant differences were observed in milk iodine or perchlorate concentrations during the two treatment periods. Estimated perchlorate intake was above the U.S. National Academy of Sciences suggested reference dose for most infants. Single daily dose iodine supplementation was not effective in decreasing milk perchlorate concentrations. Users of iodized salt had significantly higher iodine levels in milk than non-users. Iodized salt may be a more effective means of iodine supplementation than tablets. - Highlights: ► Estimated infant exposures to perchlorate were, on a μg/kg basis, ∼ 5 × higher than those of mothers. ► Daily supplements are less effective than iodized salt in providing iodine to lactating women. ► Low iodine and high perchlorate in milk may place infants at risk of iodine deficiency.

  16. Perchlorate, iodine supplements, iodized salt and breast milk iodine content

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, Andrea B. [Department of Epidemiology, School of Public Health, University of North Texas Health Sciences Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107 (United States); Kroll, Martina; Dyke, Jason V.; Ohira, Shin-Ichi; Dias, Rukshan A.; Dasgupta, Purnendu K. [Department of Chemistry and Biochemistry, 700 Planetarium Place, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2012-03-15

    This study was undertaken to determine if increasing maternal iodine intake through single dose tablets will decrease breast milk concentrations of the iodine-uptake inhibitor, perchlorate, through competitive inhibition. We also sought to determine if the timing of supplementation influences the fraction of iodine excreted in milk versus urine and to compare the effectiveness of iodized salt as a means of providing iodine to breastfed infants. Thirteen women who did not use supplements, seven of whom used iodized salt and six of whom used non-iodized salt, submitted four milk samples and a 24-h urine collection daily for three days. Women repeated the sampling protocol for three more days during which {approx} 150 {mu}g of iodine were taken in the evening and again for three days with morning supplementation. Samples were analyzed using isotope-dilution inductively-coupled plasma-mass spectrometry for iodine and isotope-dilution ion chromatography-tandem mass spectrometry for perchlorate. No statistically significant differences were observed in milk iodine or perchlorate concentrations during the two treatment periods. Estimated perchlorate intake was above the U.S. National Academy of Sciences suggested reference dose for most infants. Single daily dose iodine supplementation was not effective in decreasing milk perchlorate concentrations. Users of iodized salt had significantly higher iodine levels in milk than non-users. Iodized salt may be a more effective means of iodine supplementation than tablets. - Highlights: Black-Right-Pointing-Pointer Estimated infant exposures to perchlorate were, on a {mu}g/kg basis, {approx} 5 Multiplication-Sign higher than those of mothers. Black-Right-Pointing-Pointer Daily supplements are less effective than iodized salt in providing iodine to lactating women. Black-Right-Pointing-Pointer Low iodine and high perchlorate in milk may place infants at risk of iodine deficiency.

  17. Calcium - urine

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003603.htm Calcium - urine To use the sharing features on this ... enable JavaScript. This test measures the amount of calcium in urine. All cells need calcium in order ...

  18. Calcium supplements

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  19. Calcium Oscillations

    OpenAIRE

    Dupont, Geneviève; Combettes, Laurent; Bird, Gary S.; Putney, James W.

    2011-01-01

    Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlyin...

  20. The Investigation of Chlorate and Perchlorate/Saponite Mixtures as a Possible Source of Oxygen and Chlorine Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater

    Science.gov (United States)

    Clark, J.; Sutter, B.; Min, D. W.; Mahaffy, P.

    2016-01-01

    The Sample Analysis at Mars (SAM) instrument on board the Curiosity Rover has detected O2 and HCl gas releases from all analyzed Gale Crater sediments, which are attributed to the presence of perchlorates and/or chlorates in martian sediment. Previous SAM analog laboratory analyses found that most pure perchlorates and chlorates release O2 and HCl at different temperatures than those observed in the SAM data. Subsequent studies examined the effects of perchlorate and chlorate mixtures with Gale Crater analog iron phases, which are known to catalyze oxychlorine decomposition. Several mixtures produced O2 releases at similar temperatures as Gale Crater materials, but most of these mixtures did not produce significant HCl releases comparable to those detected by the SAM instrument. In order to better explain the Gale Crater HCl releases, perchlorates and chlorates were mixed with Gale Crater analog saponite, which is found at abundances from 8 to 20 wt % in the John Klein and Cumberland drill samples. Mixtures of chlorates or perchlorates with calcium-saponite or ferrian-saponite were heated to 1000 deg C in a Labsys EVO differential scanning calorimeter/mass spectrometer configured to operate similarly to the SAM oven/quadrupole mass spectrometer system. Our results demonstrate that all chlorate and perchlorate mixtures produce significant HCl releases below 1000 deg C as well as depressed oxygen peak release temperatures when mixed with saponite. The type of saponite (calcium or ferrian saponite) did not affect the evolved gas results significantly. Saponite/Mg-perchlorate mixtures produced two HCl releases similar to the Cumberland drilled sample. Mg-chlorate mixed with saponite produced HCl releases similar to the Big Sky drilled sample in an eolian sandstone. A mixture of Ca-perchlorate and saponite produced HCl and oxygen releases similar to the Buckskin mudstone drilled sample and the Gobabeb 2 eolian dune material. Ca-chlorate mixed with saponite produced both

  1. Developmental exposure to perchlorate alters synaptic transmission in hippocampus of the adult rat: in vivo studies.

    Science.gov (United States)

    Perchlorate, a contaminant found in food and water supplies throughout the USA, blocks iodine uptake into the thyroid gland to reduce circulating levels of thyroid hormone. Neurological function accompanying developmental exposure to perchlorate was evaluated in the present study...

  2. Chlorine isotopic composition of perchlorate in human urine as a means of distinguishing among exposure sources.

    Science.gov (United States)

    Poghosyan, Armen; Morel-Espinosa, Maria; Valentin-Blasini, Liza; Blount, Benjamin C; Ferreccio, Catterina; Steinmaus, Craig M; Sturchio, Neil C

    2016-05-01

    Perchlorate (ClO4(-)) is a ubiquitous environmental contaminant with high human exposure potential. Natural perchlorate forms in the atmosphere from where it deposits onto the surface of Earth, whereas synthetic perchlorate is manufactured as an oxidant for industrial, aerospace, and military applications. Perchlorate exposure can potentially cause adverse health effects in humans by interfering with the production of thyroid hormones through competitively blocking iodide uptake. To control and reduce perchlorate exposure, the contributions of different sources of perchlorate exposure need to be quantified. Thus, we demonstrate a novel approach for determining the contribution of different perchlorate exposure sources by quantifying stable and radioactive chlorine isotopes of perchlorate extracted from composite urine samples from two distinct populations: one in Atlanta, USA and one in Taltal, Chile (Atacama region). Urinary perchlorate from the Atlanta region resembles indigenous natural perchlorate from the western USA (δ(37)Cl=+4.1±1.0‰; (36)Cl/Cl=1 811 (±136) × 10(-15)), and urinary perchlorate from the Taltal, Chile region is similar to natural perchlorate in nitrate salt deposits from the Atacama Desert of northern Chile (δ(37)Cl=-11.0±1.0‰; (36)Cl/Cl=254 (±40) × 10(-15)). Neither urinary perchlorate resembled the isotopic pattern found in synthetic perchlorate. These results indicate that natural perchlorate of regional provenance is the dominant exposure source for the two sample populations, and that chlorine isotope ratios provide a robust tool for elucidating perchlorate exposure pathways. PMID:25805252

  3. Aluminum-based drinking-water treatment residuals: A novel sorbent for perchlorate removal

    International Nuclear Information System (INIS)

    Perchlorate contamination of aquifers and drinking-water supplies has led to stringent regulations in several states to reduce perchlorate concentrations in water at acceptable levels for human consumption. Several perchlorate treatment technologies exist, but there is significant cost associated with their use, and the majority of them are unable to degrade perchlorate to innocuous chloride. We propose the use of a novel sorbent for perchlorate, i.e. an aluminum-based drinking-water treatment residual (Al-WTR), which is a by-product of the drinking-water treatment process. Perchlorate sorption isotherms (23 ± 1 oC) showed that the greatest amount (65%) of perchlorate removed by the Al-WTR was observed with the lowest initial perchlorate load (10 mg L-1) after only 2 h of contact time. Increasing the contact time to 24 h, perchlorate removal increased from 65 to 76%. A significant correlation was observed between the amounts of perchlorate removed with evolved chloride in solution, suggesting degradation of perchlorate to chloride. - Drinking-water treatment residuals are a low-cost sorbent for perchlorate

  4. Interaction between perchlorate and iodine in the metamorphosis of Hyla versicolor

    Science.gov (United States)

    Sparling, D.W.; Harvey, G.; Nzengung, V.

    2003-01-01

    Perchlorate (ClO4-) is a water-soluble, inorganic anion that is often combined with ammonium, potassium or other cations for use in industry and agriculture. Ammonium perchlorate, for example, is a potent oxidizer and is used in various military applications including rocket fuel. It has also been found in an historically widely used fertilizer, Chilean nitrate and in other fertilizers. It has been found in ground and surface waters of over 30 states and is considered a human health risk. Because of its similar atomic radius and volume, perchlorate competes with iodide for thyroid uptake and storage and thereby inhibits production of thyroid hormones. Amphibians may be particularly affected by perchlorate because they rely on the thyroid for metamorphosis. This study exposed early larval Hyla versicolor to concentrations of perchlorate ranging from 2.2 to 50 ppm to determine the effects of perchlorate on a native amphibian. In addition, three controls, 0 perchlorate, 0 perchlorate with 0.10 ppm iodide (C + I) and 50 ppm perchlorate + 0.10 ppm iodide (50 + I) were tested. Mortality (metamorphosis. The estimated EC50 for total inhibition of metamorphosis at 70 days of treatment was 3.63 ppm. There was no evidence of inhibition of development with the 50 + I, C + I, or controls, indicating that the presence of small concentrations of iodide could counter the effects of perchlorate. When tadpoles that had been inhibited by perchlorate were subsequently treated with iodide, development through prometamorphosis progressed but mortality was very high.

  5. Competitive microbial reduction of perchlorate and nitrate with a cathode directly serving as the electron donor

    International Nuclear Information System (INIS)

    Microbial reduction of perchlorate with an electrode as the electron donor represents an emerging technology for remediation of perchlorate contamination; it is important to know how perchlorate reduction behaves when nitrate, a co-contaminant of perchlorate is present. We reported that electrons derived from the electrode can be directly transferred to the bacteria with perchlorate or nitrate as the sole electron acceptor. The presence of nitrate, even at the 0.07 mM level, can slow reduction of perchlorate (0.70 mM) as a poised potential of -0.50 V (vs. SCE) was applied to the inoculated cathode. Increasing the concentration of nitrate resulted in a noticeable inhibitory effect on perchlorate reduction. When the nitrate concentration was 2.10 mM, reduction of 0.70 mM perchlorate was totally inhibited. Bacterial community analyses based on 16S rDNA gene analysis with denaturing gradient gel electrophoresis (DGGE) revealed that most of the bacteria newly enriched on the nitrate and/or perchlorate biocathodes were the known electrochemically active denitrifiers, which possibly prefer to reduce nitrate over perchlorate. These results show that nitrate is a more favorable electron acceptor than perchlorate in the bioelectrochemical system where the cathode directly serves as the electron donor

  6. Effect of nitrate, acetate and hydrogen on native perchlorate-reducing microbial communities and their activity in vadose soil

    OpenAIRE

    Nozawa-Inoue, Mamie; Jien, Mercy; Yang, Kun; Dennis E. Rolston; Hristova, Krassimira R.; Scow, Kate M.

    2011-01-01

    Effect of nitrate, acetate and hydrogen on native perchlorate-reducing bacteria (PRB) was examined by conducting microcosm tests using vadose soil collected from a perchlorate-contaminated site. The rate of perchlorate reduction was enhanced by hydrogen amendment and inhibited by acetate amendment, compared to unamendment. Nitrate was reduced before perchlorate in all amendments. In hydrogen-amended and unamended soils, nitrate delayed perchlorate reduction, suggesting the PRB preferentially ...

  7. Branched polymeric media: Perchlorate-selective resins from hyperbranched polyethyleneimine

    KAUST Repository

    Chen, Dennis P.

    2012-10-02

    Perchlorate (ClO4 -) is a persistent contaminant found in drinking groundwater sources in the United States. Ion exchange (IX) with selective and disposable resins based on cross-linked styrene divinylbenzene (STY-DVB) beads is currently the most commonly utilized process for removing low concentrations of ClO4 - (10-100 ppb) from contaminated drinking water sources. However, due to the low exchange capacity of perchlorate-selective STY-DVB resins (∼0.5-0.8 eq/L), the overall cost becomes prohibitive when treating groundwater with higher concentration of ClO4 - (e.g., 100-1000 ppb). In this article, we describe a new perchlorate-selective resin with high exchange capacity. This new resin was prepared by alkylation of branched polyethyleneimine (PEI) beads obtained from an inverse suspension polymerization process. Batch and column studies show that our new PEI resin with mixed hexyl/ethyl quaternary ammonium chloride exchange sites can selectively extract trace amounts of ClO4 - from a makeup groundwater (to below detection limit) in the presence of competing ions. In addition, this resin has a strong-base exchange capacity of 1.4 eq/L, which is 1.75-2.33 times larger than those of commercial perchlorate-selective STY-DVB resins. The overall results of our studies suggest that branched PEI beads provide versatile and promising building blocks for the preparation of perchlorate-selective resins with high exchange capacity. © 2012 American Chemical Society.

  8. Sample processing method for the determination of perchlorate in milk

    International Nuclear Information System (INIS)

    In recent years, many different water sources and foods have been reported to contain perchlorate. Studies indicate that significant levels of perchlorate are present in both human and dairy milk. The determination of perchlorate in milk is particularly important due to its potential health impact on infants and children. As for many other biological samples, sample preparation is more time consuming than the analysis itself. The concurrent presence of large amounts of fats, proteins, carbohydrates, etc., demands some initial cleanup; otherwise the separation column lifetime and the limit of detection are both greatly compromised. Reported milk processing methods require the addition of chemicals such as ethanol, acetic acid or acetonitrile. Reagent addition is undesirable in trace analysis. We report here an essentially reagent-free sample preparation method for the determination of perchlorate in milk. Milk samples are spiked with isotopically labeled perchlorate and centrifuged to remove lipids. The resulting liquid is placed in a disposable centrifugal ultrafilter device with a molecular weight cutoff of 10 kDa, and centrifuged. Approximately 5-10 ml of clear liquid, ready for analysis, is obtained from a 20 ml milk sample. Both bovine and human milk samples have been successfully processed and analyzed by ion chromatography-mass spectrometry (IC-MS). Standard addition experiments show good recoveries. The repeatability of the analytical result for the same sample in multiple sample cleanup runs ranged from 3 to 6% R.S.D. This processing technique has also been successfully applied for the determination of iodide and thiocyanate in milk

  9. Perchlorate exposure in lactating women in an urban community in New Jersey

    International Nuclear Information System (INIS)

    Perchlorate is most widely known as a solid oxidant for missile and rocket propulsion systems although it is also present as a trace contaminant in some fertilizers. It has been detected in drinking water, fruits, and vegetables throughout New Jersey and most of the United States. At sufficiently high doses, perchlorate interferes with the uptake of iodine into the thyroid and may interfere with the development of the skeletal system and the central nervous system of infants. Therefore, it is important to quantify perchlorate in breast milk to understand potential perchlorate exposure in infants. In this study we measured perchlorate in breast milk, urine, and drinking water collected from 106 lactating mothers from Central New Jersey. Each subject was asked to provide three sets of samples over a 3-month period. The average ± SD perchlorate level in drinking water, breast milk, and urine was 0.168 ± 0.132 ng/mL (n = 253), 6.80 ± 8.76 ng/mL (n = 276), and 3.19 ± 3.64 ng/mL (3.51 ± 6.79 μg/g creatinine) (n = 273), respectively. Urinary perchlorate levels were lower than reference range values for women of reproductive age (5.16 ± 11.33 μg/g creatinine, p = 0.03), likely because of perchlorate secretion in breast milk. Drinking water perchlorate levels were ≤ 1.05 ng/mL and were not positively correlated with either breast milk or urine perchlorate levels. These findings together suggest that drinking water was not the most important perchlorate exposure source for these women. Creatinine-adjusted urine perchlorate levels were strongly correlated with breast milk perchlorate levels (r = 0.626, p = < 0.0005). Breast milk perchlorate levels in this study are consistent with widespread perchlorate exposure in lactating women and thus infants. This suggests that breast milk may be a source of exposure to perchlorate in infants. - Research Highlights: → The general population, including infants, is exposed to perchlorate. → Breast milk is a significant

  10. Inhibition of perchlorate reduction by nitrate in a fixed biofilm reactor

    International Nuclear Information System (INIS)

    Perchlorate and nitrate were reduced simultaneously in fixed biofilm reactors. Reduction of 1000 μg L-1 perchlorate decreased slightly with the addition of 10-16 mg L-1 NO3-N when excess acetate was supplied while denitrification was complete. When influent acetate was reduced by 50% to well below the stoichiometric requirement, perchlorate reduction decreased by 70% while denitrification decreased by only 20%, suggesting that competition for electrons by nitrate was a factor in inhibition. Reduction of nitrate was favored over perchlorate, even though reactor biofilm had been enriched under perchlorate-reducing conditions for 10 months. When excess acetate was restored, perchlorate and nitrate returned to initial levels. The average most probable numbers of perchlorate- and nitrate-reducing bacteria during excess substrate operation were not significantly different and ranged between 2.0 x 105 and 7.9 x 105 cells cm-2 media surface area. The effect of nitrate on chloride generation by suspensions of perchlorate-reducing populations was studied using a chloride ion probe. The rate of reduction of 2 mM perchlorate decreased by 30% in the presence of 2 mM nitrate when excess acetate was added. When acetate was limited, perchlorate reduction decreased by 70% in the presence of equi-molar nitrate

  11. Detection of Perchlorate Anion on Functionalized Silver Colloids Using Surface-Enhanced Raman Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Tio, J.; Wang, W.; Gu, B.

    2005-01-01

    Perchlorate anion interferes with the uptake of iodide by the human thyroid gland and consequently disrupts the regulation of metabolism. Chronic exposure to high levels of perchlorate may lead to the formation of thyroid gland tumors. Although the Environmental Protection Agency (EPA) has not set a maximum contaminant level (MCL) for perchlorate, a draft drinking water range of 4-18 ppb based on 2 liter daily consumption of water has been established. The current EPA approved method for detecting perchlorate uses ion chromatography which has a detection limit of ~1ppb and involves lengthy analytical time in the laboratory. A unique combination of the surface-enhanced Raman scattering (SERS) effect and the bifunctional anion exchange resin’s high selectivity may provide an alternative way to detect perchlorate at such low concentrations and with high specificity. SERS, which uses laser excitation of adsorbed perchlorate anions on silver nanoparticles, has been shown to detect perchlorate anions at concentrations as low as 50 ppb. Normal micro-Raman analysis of perchlorate sorbed onto the resin beads has detected an even lower concentration of 10 ppb. In an effort to integrate these two effects, silver nanoparticles were coated with N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride, a functional group similar to that found on the resin bead, and subsequently inserted into different perchlorate concentration environments. This method has resulted in perchlorate detection down to ~10 ppb and a more consistent detection of perchlorate anion at ~50 ppb than that of earlier methods. As suggested by the direct insertion of functionalized silver colloids into perchlorate samples, this technique may potentially allow for the development of a probe using on-site Raman spectrometry to detect significantly low concentrations of perchlorate in situ rather than in the laboratory.

  12. Relative source contributions for perchlorate exposures in a lactating human cohort

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, Andrea B. [University of North Texas Health Sciences Center (United States); Dyke, Jason V. [University of Texas at Arlington (United States); Ohira, Shin-Ichi [Kumamoto University (Japan); Dasgupta, Purnendu K., E-mail: Dasgupta@uta.edu [University of Texas at Arlington (United States)

    2013-01-15

    Perchlorate is an iodine-uptake inhibitor and common contaminant of food and drinking water. Understanding the amount of perchlorate exposure occurring through non-water sources is essential for accurate estimates of human exposure levels, and establishment of drinking water limits for this pervasive contaminant. The study objective was to determine the amount of perchlorate intake derived from diet rather than water. Subjects provided drinking water samples, detailed fluid-intake records, 24 h urine collections and four milk samples for nine days. Samples were analyzed for perchlorate by isotope dilution ion chromatography–tandem mass spectrometry. Amounts of perchlorate derived from drinking water and dietary sources were calculated for each individual. Water of local origin was found to contribute a minor fraction of perchlorate intake. Estimated fraction intake from drinking water ranged from 0 to 36%. The mean and median dose of perchlorate derived from non-water sources by lactating women was 0.18 μg/kg/day (range: 0.06 to 0.36 μg/kg/day.) Lactating women consumed more fluid (mean 2.424 L/day) than has been assumed in recent risk assessments for perchlorate. The data reported here indicate that lactating women may be exposed to perchlorate through dietary sources at markedly higher levels than estimated previously. Exposures to perchlorate from non-water sources may be higher than recent estimates, including those used to develop drinking water standards. - Highlights: ► Residence in an area with perchlorate-contaminated water may be a poor predictor of exposure. ► Exposures to perchlorate from food are likely underestimated. ► The relative contributions for human perchlorate exposures should be weighted more heavily towards non-water sources.

  13. Relative source contributions for perchlorate exposures in a lactating human cohort

    International Nuclear Information System (INIS)

    Perchlorate is an iodine-uptake inhibitor and common contaminant of food and drinking water. Understanding the amount of perchlorate exposure occurring through non-water sources is essential for accurate estimates of human exposure levels, and establishment of drinking water limits for this pervasive contaminant. The study objective was to determine the amount of perchlorate intake derived from diet rather than water. Subjects provided drinking water samples, detailed fluid-intake records, 24 h urine collections and four milk samples for nine days. Samples were analyzed for perchlorate by isotope dilution ion chromatography–tandem mass spectrometry. Amounts of perchlorate derived from drinking water and dietary sources were calculated for each individual. Water of local origin was found to contribute a minor fraction of perchlorate intake. Estimated fraction intake from drinking water ranged from 0 to 36%. The mean and median dose of perchlorate derived from non-water sources by lactating women was 0.18 μg/kg/day (range: 0.06 to 0.36 μg/kg/day.) Lactating women consumed more fluid (mean 2.424 L/day) than has been assumed in recent risk assessments for perchlorate. The data reported here indicate that lactating women may be exposed to perchlorate through dietary sources at markedly higher levels than estimated previously. Exposures to perchlorate from non-water sources may be higher than recent estimates, including those used to develop drinking water standards. - Highlights: ► Residence in an area with perchlorate-contaminated water may be a poor predictor of exposure. ► Exposures to perchlorate from food are likely underestimated. ► The relative contributions for human perchlorate exposures should be weighted more heavily towards non-water sources

  14. Isotopic tracing of perchlorate sources in groundwater from Pomona, California

    International Nuclear Information System (INIS)

    Highlights: • Isotopic analysis of groundwater perchlorate can provide source identification. • Citrus cultivation in Pomona, CA caused perchlorate contamination of groundwater. • Hydrologic modeling and mass balance support interpretation of perchlorate source. - Abstract: The groundwater of Pomona, California, is contaminated with perchlorate (ClO4-). This water is treated to reduce the ClO4- concentration to less than 6 μg L−1 for compliance with California Department of Public Health drinking water regulations. A study of the isotopic composition of oxygen and chlorine in ClO4- has been conducted to determine the source of the contamination. Isotopic compositions were measured for ClO4- samples extracted from 14 wells, yielding ranges of δ18O values from −10.8‰ to −8.0‰, Δ17O values from +4.6‰ to +7.5‰, and δ37Cl values from −12.8‰ to −8.9‰. Evaluation of mixing proportions using published isotopic data for three ClO4- end-members (synthetic, Atacama, and indigenous natural ClO4-) indicates that contamination is dominantly (85–89%) Atacama ClO4- derived from past use of imported Chilean nitrate fertilizer in citrus cultivation. This interpretation is consistent with (1) aerial photography archives showing extensive citrus fields surrounding Pomona in the early- to mid-20th century, (2) mass-balance estimates for ClO4-, and (3) numerical hydrologic models yielding travel-times for ClO4- from fields to wells that are in the range of 15 to >100 years. The hydrologic models predict that ClO4- contamination of Pomona groundwater will persist for decades into the future

  15. 4-(2-Azaniumylethylpiperazin-1-ium bis(perchlorate

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Reisi

    2011-09-01

    Full Text Available In the title compound, C6H17N32+·2ClO4−, the piperazine ring adopts a chair conformation with the ethylammonium fragment occupying an equatorial position. In the crystal, the dications and perchlorate anions are linked through N—H...O hydrogen bonding and weak C—H...O hydrogen bonding into a three-dimensional supramolecular network.

  16. Genetic Factors That Might Lead to Different Responses in Individuals Exposed to Perchlorate

    OpenAIRE

    Scinicariello, Franco; Murray, H. Edward; Smith, Lester; Wilbur, Sharon; Fowler, Bruce A.

    2005-01-01

    Perchlorate has been detected in groundwater in many parts of the United States, and recent detection in vegetable and dairy food products indicates that contamination by perchlorate is more widespread than previously thought. Perchlorate is a competitive inhibitor of the sodium iodide symporter, the thyroid cell–surface protein responsible for transporting iodide from the plasma into the thyroid. An estimated 4.3% of the U.S. population is subclinically hypothyroid, and 6.9% of pregnant wome...

  17. Purification and Characterization of (Per)Chlorate Reductase from the Chlorate-Respiring Strain GR-1

    OpenAIRE

    Kengen, Servé W. M.; Rikken, Geoffrey B.; Hagen, Wilfred R.; van Ginkel, Cees G.; Stams, Alfons J. M.

    1999-01-01

    Strain GR-1 is one of several recently isolated bacterial species that are able to respire by using chlorate or perchlorate as the terminal electron acceptor. The organism performs a complete reduction of chlorate or perchlorate to chloride and oxygen, with the intermediate formation of chlorite. This study describes the purification and characterization of the key enzyme of the reductive pathway, the chlorate and perchlorate reductase. A single enzyme was found to catalyze both the chlorate-...

  18. Transposon and Deletion Mutagenesis of Genes Involved in Perchlorate Reduction in Azospira suillum PS

    OpenAIRE

    Melnyk, Ryan A.; Clark, Iain C.; Liao, Annette; Coates, John D.

    2013-01-01

    ABSTRACT Although much work on the biochemistry of the key enzymes of bacterial perchlorate reduction, chlorite dismutase, and perchlorate reductase has been published, understanding of the molecular mechanisms of this metabolism has been somewhat hampered by the lack of a clear model system amenable to genetic manipulation. Using transposon mutagenesis and clean deletions, genes important for perchlorate reduction in Azospira suillum PS have been identified both inside and outside the previo...

  19. Extraction of scandium ions by 1-alkyl-3-methyl-2-pyrazoline-5-ones from perchlorate solutions

    International Nuclear Information System (INIS)

    Extraction of acid and interphase distribution of 1-alkyl-3-methyl-2-pyrazoline-5-ones in the system water-chloroform-perchloric acid are studied. Reagents capable to extract scandium cations from subacid solutions in the presence of perchlorate ions. 1-Alkyl-3-methyl-2-pyrazoline-5-ones stratifies aqueous solutions of perchloric acid into two liquid phase. Scandium ions are concentrated in the lower phase having small volume

  20. Uranyl ion behaviour in perchloric media and its extraction by TBP CCl/sub 4/

    Energy Technology Data Exchange (ETDEWEB)

    Yahia, A. (Centre de Developpement des Materiaux, Commissariat aux Energies Nouvelles, Alger (Algeria)); Benali-Baitich, O. (Universite des Sciences et de la Technologie Houari Boumediene (USTHB), Institut de Chimie, Alger (Algeria))

    The behaviour of uranyl ion in aqueous solution of perchloric acid (O < Cub(HC104) < 13 mol.1/sup -1/) shows that for an acidity higher than 9 mol.1/sup -1/, there is formation of a monoperchlorato complex. The extraction of uranly perchlorate from aqueous perchloric solutions by TBP diluted CC1/sub 4/ as a function of uranium and perchloric acid concentrations enabled us on one hand, to concluded that UO/sub 2//sup + +/ is solvated by 2 TBP molecules, and on the other hand, to determine the composition of the coextracted HC1O/sub 4/ solvated species.

  1. Perchlorate in fish from a contaminated site in east-central Texas

    International Nuclear Information System (INIS)

    Perchlorate, a known thyroid endocrine disruptor, contaminates surface waters near military instillations where solid fuel rocket motors are manufactured or assembled. To assess potential perchlorate exposure to fish and the human population which may feed on them, fish were collected around the Naval Weapons Industrial Reserve Plant in McLennan County, TX, and analyzed for the presence of the perchlorate anion. The sampling sites included Lake Waco and Belton Lake, and several streams and rivers within their watersheds. The general tendency was that perchlorate was only found in a few species sampled, and perchlorate was not detected in every individual within these species. When detected in the fish, perchlorate tissue concentrations were greater than that in the water. This may be due to highly variable perchlorate concentrations in the water coupled with individual-level variation in elimination from the body, or to routes of exposure other than water. - In perchlorate-contaminated lakes and streams, perchlorate is detected infrequently in fish heads, fillets, and whole bodies, but may be detected more often depending on species and seasonal trends, and always at concentrations higher in the fish than in the water

  2. Containerized Wetland Bioreactor Evaluated for Perchlorate and Nitrate Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Dibley, V R; Krauter, P W

    2004-12-02

    The U.S. Department of Energy (DOE) and Lawrence Livermore Laboratory (LLNL) designed and constructed an innovative containerized wetlands (bioreactor) system that began operation in November 2000 to biologically degrade perchlorate and nitrate under relatively low-flow conditions at a remote location at Site 300 known as Building 854. Since initial start-up, the system has processed over 3,463,000 liters of ground water and treated over 38 grams of perchlorate and 148 kilograms of nitrate. Site 300 is operated by the University of California as a high-explosives and materials testing facility supporting nuclear weapons research. The 11-square mile site located in northern California was added to the NPL in 1990 primarily due to the presence of elevated concentrations of volatile organic compounds (VOCs) in ground water. At the urging of the regulatory agencies, perchlorate was looked for and detected in the ground water in 1999. VOCs, nitrate and perchlorate were released into the soil and ground water in the Building 854 area as the result of accidental leaks during stability testing of weapons or from waste discharge practices that are no longer permitted at Site 300. Design of the wetland bioreactors was based on earlier studies showing that indigenous chlorate-respiring bacteria could effectively degrade perchlorate into nontoxic concentrations of chlorate, chlorite, oxygen, and chloride. Studies also showed that the addition of organic carbon would enhance microbial denitrification. Early onsite testing showed acetic acid to be a more effective carbon source than dried leaf matter, dried algae, or milk replacement starter; a nutrient and carbon source used in a Department of Defense phytoremediation demonstration. No inocula were added to the system. Groundwater was allowed to circulate through the bioreactor for three weeks to acclimate the wetland plants and to build a biofilm from indigenous flora. Using solar energy, ground water is pumped into granular

  3. Perchlorate in the Hydrologic Cycle - An Overview of Sources and Occurrence

    Science.gov (United States)

    Stonestrom, D. A.; Jackson, W.; Mayer, K.; Orris, G. J.

    2007-12-01

    Perchlorate (ClO4-) in water and food is of concern due to deleterious health affects associated with hypothyroidism. The presence of widespread perchlorate in 0-to-28 ka-old pristine ground water of the Middle Rio Grande Basin (Plummer et al., 2006, ES&T, DOI:10.1021/es051739h), in ground water >1 mile from agricultural activities in the Southern High Plains (Rajagapolan et al., 2006, ES&T, DOI:10.1021/es052155i), and in unsaturated zones throughout the arid and semiarid southwestern United States (Rao et al., 2007, ES&T, DOI:10.1021/es062853i) clearly indicates that perchlorate is a non-exotic component of the hydrologic cycle, at least in dry environments. The natural system has been greatly perturbed in places by human activities. Most anthropogenic inputs are associated with the manufacture and use of explosives and rocket fuel, providing concentrated sources of excess perchlorate to the hydrologic cycle. Perchlorate-containing fertilizers and irrigation provide dispersed sources within and down-gradient from agricultural areas. Natural sources include photochemically mediated reactions involving ozone at the land surface and in the lower atmosphere. A growing body of work indicates that a small, but persistent, meteoric source acting over thousands of years can explain observed accumulations of unsaturated-zone perchlorate in arid regions. In addition to meteoric sources, oxyanions produced during volcanogenic processes can include appreciable amounts of natural perchlorate. Terrestrial plants take up perchlorate in soil water, with some species of xerophytic succulents concentrating the anion to high levels. Similarly, perchlorate in marine plants indicates that perchlorate is part of marine biochemical cycles. Perchlorate-bearing marine sediments of late Tertiary age suggest that perchlorate has been part of global geochemical cycles for millions of years and, furthermore, can be preserved in the subsurface despite the nearly ubiquitous presence of

  4. Physiological and Genetic Description of Dissimilatory Perchlorate Reduction by the Novel Marine Bacterium Arcobacter sp. Strain CAB

    OpenAIRE

    Carlström, Charlotte I.; Wang, Ouwei; Melnyk, Ryan A.; Bauer, Stefan; Lee, Joyce; Engelbrektson, Anna; Coates, John D.

    2013-01-01

    ABSTRACT A novel dissimilatory perchlorate-reducing bacterium (DPRB), Arcobacter sp. strain CAB, was isolated from a marina in Berkeley, CA. Phylogenetically, this halophile was most closely related to Arcobacter defluvii strain SW30-2 and Arcobacter ellisii. With acetate as the electron donor, strain CAB completely reduced perchlorate (ClO4 −) or chlorate (ClO3 −) [collectively designated (per)chlorate] to innocuous chloride (Cl−), likely using the perchlorate reductase (Pcr) and chlorite di...

  5. Bifunctional lanthanum phosphate substrates as novel adsorbents and biocatalyst supports for perchlorate removal

    Energy Technology Data Exchange (ETDEWEB)

    Sankar, Sasidharan [Materials Science and Technology Division (India); Prajeesh, Gangadharan Puthiya Veetil; Anupama, Vijaya Nadaraja [Process Engineering and Environmental Technology Division, CSIR – National Institute for Interdisciplinary Science and Technology, Industrial Estate P.O., Thiruvananthapuram 695019 (India); Krishnakumar, Bhaskaran [Process Engineering and Environmental Technology Division, CSIR – National Institute for Interdisciplinary Science and Technology, Industrial Estate P.O., Thiruvananthapuram 695019 (India); Academy of Scientific and Industrial Research (AcSIR) (India); Hareesh, Padinhattayil [Materials Science and Technology Division (India); Nair, Balagopal N. [R and D Centre, Noritake Co. Ltd., Aichi (Japan); Warrier, Krishna Gopakumar [Materials Science and Technology Division (India); Academy of Scientific and Industrial Research (AcSIR) (India); Hareesh, Unnikrishnan Nair Saraswathy, E-mail: hareesh@niist.res.in [Materials Science and Technology Division (India); Academy of Scientific and Industrial Research (AcSIR) (India)

    2014-06-30

    Graphical abstract: Porous lanthanum phosphate substrates, obtained by an environmentally benign thermal gelation process, performed the role of dual functional sorbent facilitating perchlorate adsorption and bioremediation through the growth of perchlorate reducing microbial colonies. - Highlights: • Lanthanum phosphate monoliths as efficient perchlorate adsorbents. • And also as substrates for biofilm (perchlorate reducing bacteria) growth. • Environmentally benign thermal gelation process for substrate fabrication. • 98% adsorption efficiency for perchlorate concentrations up to 100 μg/L. • The regenerated monoliths show nearly 100% reusability. - Abstract: Porous lanthanum phosphate substrates, obtained by an environmentally benign colloidal forming process employing methyl cellulose, are reported here as excellent adsorbents of perchlorate with >98% efficiency and with 100% reusability. Additionally, the effectiveness of such substrates as biocatalyst supports that facilitate biofilm formation of perchlorate reducing microbes (Serratia marcescens NIIST 5) is also demonstrated for the first time. The adsorption of perchlorate ions is attributed to the pore structure of lanthanum phosphate substrate and the microbial attachment is primarily ascribed to its intrinsic hydrophobic property. Lanthanum phosphate thus emerges as a dual functional material that possesses an integrated adsorption/bioremediation property for the effective removal of ClO{sub 4}{sup −} which is an increasingly important environmental contaminant.

  6. Identification of a Perchlorate Reduction Genomic Island with Novel Regulatory and Metabolic Genes ▿

    OpenAIRE

    Melnyk, Ryan A.; Engelbrektson, Anna; Clark, Iain C.; Carlson, Hans K.; Byrne-Bailey, Kathy; Coates, John D.

    2011-01-01

    A comparative analysis of the genomes of four dissimilatory (per)chlorate-reducing bacteria has revealed a genomic island associated with perchlorate reduction. In addition to the characterized metabolic genes for perchlorate reductase and chlorite dismutase, the island contains multiple conserved uncharacterized genes possibly involved in electron transport and regulation.

  7. Identification of a perchlorate reduction genomic island with novel regulatory and metabolic genes.

    Science.gov (United States)

    Melnyk, Ryan A; Engelbrektson, Anna; Clark, Iain C; Carlson, Hans K; Byrne-Bailey, Kathy; Coates, John D

    2011-10-01

    A comparative analysis of the genomes of four dissimilatory (per)chlorate-reducing bacteria has revealed a genomic island associated with perchlorate reduction. In addition to the characterized metabolic genes for perchlorate reductase and chlorite dismutase, the island contains multiple conserved uncharacterized genes possibly involved in electron transport and regulation. PMID:21856823

  8. Bifunctional lanthanum phosphate substrates as novel adsorbents and biocatalyst supports for perchlorate removal

    International Nuclear Information System (INIS)

    Graphical abstract: Porous lanthanum phosphate substrates, obtained by an environmentally benign thermal gelation process, performed the role of dual functional sorbent facilitating perchlorate adsorption and bioremediation through the growth of perchlorate reducing microbial colonies. - Highlights: • Lanthanum phosphate monoliths as efficient perchlorate adsorbents. • And also as substrates for biofilm (perchlorate reducing bacteria) growth. • Environmentally benign thermal gelation process for substrate fabrication. • 98% adsorption efficiency for perchlorate concentrations up to 100 μg/L. • The regenerated monoliths show nearly 100% reusability. - Abstract: Porous lanthanum phosphate substrates, obtained by an environmentally benign colloidal forming process employing methyl cellulose, are reported here as excellent adsorbents of perchlorate with >98% efficiency and with 100% reusability. Additionally, the effectiveness of such substrates as biocatalyst supports that facilitate biofilm formation of perchlorate reducing microbes (Serratia marcescens NIIST 5) is also demonstrated for the first time. The adsorption of perchlorate ions is attributed to the pore structure of lanthanum phosphate substrate and the microbial attachment is primarily ascribed to its intrinsic hydrophobic property. Lanthanum phosphate thus emerges as a dual functional material that possesses an integrated adsorption/bioremediation property for the effective removal of ClO4− which is an increasingly important environmental contaminant

  9. Terbium nitrate luminescence quenching by eosin in he presence of lithium perchlorate in sulfolane solutions

    International Nuclear Information System (INIS)

    Quenching of terbium nitrate luminescence by anionic dye, eosin, in the presence of lithium perchlorate in sulfolane solutions was studied. Temperature dependence of terbium nitrate luminescence in sulfolane solutions in the presence of perchlorate anions were considered. The values of energy required for water molecular substitution in Tb3+ ion coordination sphere for solvent molecule in electrolyte solution were ascertained

  10. Archaeal (Per)Chlorate Reduction at High Temperature: An Interplay of Biotic and Abiotic Reactions

    NARCIS (Netherlands)

    Liebensteiner, M.; Pinkse, M.W.H.; Schaap, P.J.; Stams, A.J.M.; Lomans, B.P.

    2013-01-01

    Perchlorate and chlorate anions [(per)chlorate] exist in the environment from natural and anthropogenic sources, where they can serve as electron acceptors for bacteria. We performed growth experiments combined with genomic and proteomic analyses of the hyperthermophile Archaeoglobus fulgidus that s

  11. Monitoring of perchlorate in diverse foods and its estimated dietary exposure for Korea populations.

    Science.gov (United States)

    Lee, Ji-Woo; Oh, Sung-Hee; Oh, Jeong-Eun

    2012-12-01

    The perchlorate concentrations in various Korean food samples were monitored, and 663 samples belonging to 39 kinds of food were analyzed. The analysis results revealed that dairy products contain the highest average concentration of 6.34 μg/kg and high detection frequency of over 85%. Fruit and vegetables showed the next highest perchlorate concentration with an average of 6.17 μg/kg. Especially, with its average concentration of 39.9 μg/kg, spinach showed the highest perchlorate level among all target food samples studied. Tomato was followed by spinach, which showed a high perchlorate average concentration of 19.8 μg/kg, and over 7 μg/kg was detected in ham and sausage (avg. 7.31 μg/kg) and in instant noodles (avg. 7.58 μg/kg). Less than 2 μg/kg was detected in fishes, meats and beverages. The exposure dose of perchlorate in Korean by food intake was calculated on the basis of the analyzed perchlorate levels in this study. The daily perchlorate dose to which Korean adults are exposed is 0.04 μg/kg bw/day, which is lower than the RfD (0.7 μg/kg bw/day) value suggested by US NAS. This result indicates that Korean people's current exposure to perchlorate from domestic food consumption is evaluated as safe. PMID:23116718

  12. Photodimerization and photooxygenation of 9-vinylcarbazole catalyzed by titanium dioxide and magnesium perchlorate

    Institute of Scientific and Technical Information of China (English)

    Hajime; Maeda; Mio; Yamamoto; Hideyuki; Nakagawa; Kazuhiko; Mizuno

    2010-01-01

    Photoreaction of 9-vinylcarbazole in acetonitrile in the presence of titanium dioxide and a catalytic amount of magnesium perchlorate gave 3,6-di(9-carbazolyl)-1,2-dioxane as a photooxygenated product via photodimerization of 9-vinylcarbazole.The photoreaction proceeds via an electron transfer mechanism,where magnesium perchlorate accelerated formation of the photo-oxygenated product.

  13. CRYSTALLIZATION KINETICS OF AMMONIUM PERCHLORATE IN AN AGITATED VESSEL

    Directory of Open Access Journals (Sweden)

    Nahidh Kaseer

    2013-05-01

    Full Text Available 31Overall crystal growth kinetics for ammonium perchlorate in laboratory scale batch  agitated vessel crystallizer have been determined from batch experiments performed in an integral mode. The effects of temperature between 30-60ºC, seed size 0.07, 0.120 and 0.275 mm and stirrer speed 160, 340, and 480 rpm, on the kinetics of crystal growth were investigated. Two different methods, viz. polynomial fitting and initial derivative were used to predict the kinetics expression. In general both methods gave comparable results for growth kinetics estimation. The order of growth process is not more than two. The activation energy for crystal growth of ammonium perchlorate was determined and found  to be equal to 5.8 kJ/ mole.            Finally, the influence of the affecting parameters on the crystal growth rate gives general expression that had an obvious dependence of the growth rate on each variables of concern (temperature, seed size, and stirrer speed .The general overall growth rate expression had shown that super saturation is the most significant variable. While the positive dependence of the stirrer speed demonstrates the importance of the diffusional step in the growth rate model. Moreover, the positive dependence of the seed size demonstrate the importance of the surface integration  step in the growth rate model. All the studied variables tend to suggest that the growth rate characteristics  of ammonium perchlorate from aqueous solution commenced in a batch crystallizer are diffusion kinetic controlled process.

  14. (Dicyanamido)[tris(2-pyridylmethyl)amine]zinc(II) perchlorate

    OpenAIRE

    Shi Guo Zhang; Hong Yan Zhao; Hong Li

    2008-01-01

    In the title complex, [Zn(C2N3)(C18H18N4)]ClO4, the ZnII ion has a slightly distorted trigonal–bipyramidal ZnN5 coordination geometry. The crystal structure is stabilized by weak intermolecular C—H...O and C—H...N hydrogen bonds. In addition, there are relatively close contacts between the O atoms of the perchlorate anion and symmetry-related pyridine rings [O...Cg = 3.179 (3) and 3.236 (3) Å, where Cg is the centroid of a pyridine ring], and between t...

  15. CRYSTALLIZATION KINETICS OF AMMONIUM PERCHLORATE IN AN AGITATED VESSEL

    OpenAIRE

    Nahidh Kaseer; Rafi' J. Yaqub; Ahmed Khalid

    2013-01-01

    31Overall crystal growth kinetics for ammonium perchlorate in laboratory scale batch  agitated vessel crystallizer have been determined from batch experiments performed in an integral mode. The effects of temperature between 30-60ºC, seed size 0.07, 0.120 and 0.275 mm and stirrer speed 160, 340, and 480 rpm, on the kinetics of crystal growth were investigated. Two different methods, viz. polynomial fitting and initial derivative were used to predict the kinetics expression. In general both me...

  16. Prediction of Particle Size of Ammonium Perchlorate during Pulverisation

    Directory of Open Access Journals (Sweden)

    Sunil Jain

    2006-07-01

    Full Text Available Ammonium perchlorate has been pulverised by an impact mill (air classifier mill to studythe influence of different operating parameters, viz., effect of mill speed, classifier speed, feedrate, and damper opening (suction rate on the particle size. Further based on the differentgrinding parameters, an empirical equation has been developed and used for the prediction ofparticle size. The experimental results indicate that the values are very close to the predictedones. In addition, particle size distribution has also been studied by applying different modelequations and it has been found that Rosin-Rammler model is the most suitable model for thisoperation.

  17. Comparative DFT study of crystalline ammonium perchlorate and ammonium dinitramide.

    Science.gov (United States)

    Zhu, Weihua; Wei, Tao; Zhu, Wei; Xiao, Heming

    2008-05-22

    The electronic structure, vibrational properties, absorption spectra, and thermodynamic properties of crystalline ammonium perchlorate (AP) and ammonium dinitramide (ADN) have been comparatively studied using density functional theory in the local density approximation. The results shows that the p states for the two solids play a very important role in their chemical reaction. From the low frequency to high frequency region, ADN has more motion modes for the vibrational frequencies than AP. The absorption spectra of AP and ADN display a few, strong bands in the fundamental absorption region. The thermodynamic properties show that ADN is easier to decompose than AP as the temperature increases. PMID:18396853

  18. Specific heat and thermodynamic properties of the cesium perchlorate

    International Nuclear Information System (INIS)

    The cesium perchlorate specific heat has been measured in a vacuum adiabatic microcalorimeter in the 10-365 K range. On the basis of the data obtained the thermodynamic functions are calculated. Csub(p)sup(0) (298.15 K) = 110.4+-0.2 J/Kxmol; S0 (298.15 K)=175.9+-0.5 J/Kxmol; H0 (298.15 K) - H0(0)=22280+-50 J/mol; - [G0 (289.15 K) - H0(0)]/T = 101.2+-0.2 J/Kxmol

  19. Detoxification of PAX-21 ammunitions wastewater by zero-valent iron for microbial reduction of perchlorate.

    Science.gov (United States)

    Ahn, Se Chang; Cha, Daniel K; Kim, Byung J; Oh, Seok-Young

    2011-08-30

    US Army and the Department of Defense (DoD) facilities generate perchlorate (ClO(4)(-)) from munitions manufacturing and demilitarization processes. Ammonium perchlorate is one of the main constituents in Army's new main charge melt-pour energetic, PAX-21. In addition to ammonium perchlorate, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitroanisole (DNAN) are the major constituents of PAX-21. In order to evaluate microbial perchlorate reduction as a practical option for the treatment of perchlorate in PAX-21 wastewater, we conducted biodegradation experiments using glucose as the primary sources of electrons and carbon. Batch experiments showed that negligible perchlorate was removed in microbial reactors containing PAX-21 wastewater while control bottles containing seed bacteria and glucose rapidly and completely removed perchlorate. These results suggested that the constituents in PAX-21 wastewater may be toxic to perchlorate reducing bacteria. A series of batch toxicity test was conducted to identify the toxic constituents in PAX-21 and DNAN was identified as the primary toxicant responsible for inhibiting the activity of perchlorate reducing bacteria. It was hypothesized that pretreatment of PAX-21 by zero-valent iron granules will transform toxic constituents in PAX-21 wastewater to non-toxic products. We observed complete reduction of DNAN to 2,4-diaminoanisole (DAAN) and RDX to formaldehyde in abiotic iron reduction study. After a 3-day acclimation period, perchlorate in iron-treated PAX-21 wastewater was rapidly decreased to an undetectable level in 2 days. This result demonstrated that iron treatment not only removed energetic compounds but also eliminated the toxic constituents that inhibited the subsequent microbial process. PMID:21700387

  20. Characterization of Perchlorate in a New Frozen Human Urine Standard Reference Material

    Science.gov (United States)

    Yu, Lee L.; Jarrett, Jeffery M.; Davis, W. Clay; Kilpatrick, Eric L.; Oflaz, Rabia; Turk, Gregory C.; Leber, Dennis D.; Valentin, Liza; Morel-Espinosa, Maria; Blount, Benjamin C.

    2015-01-01

    Perchlorate, an inorganic anion, has recently been recognized as an environmental contaminant by the U.S. Environmental Protection Agency (EPA). Urine is the preferred matrix for assessment of human exposure to perchlorate. Although the measurement technique for perchlorate in urine was developed in 2005, the calibration and quality assurance aspects of the metrology infrastructure for perchlorate are still lacking in that there is no certified reference material (CRM) traceable to the International System of Units (SI). To meet the quality assurance needs in biomonitoring measurements of perchlorate and the related anions that affect thyroid health, the National Institute of Standards and Technology (NIST) in collaboration with the Centers for Disease Control and Prevention (CDC) developed Standard Reference Material (SRM) 3668 Mercury, Perchlorate, and Iodide in Frozen Human Urine. SRM 3668 consists of perchlorate, nitrate, thiocyanate, iodine, and mercury in urine at two levels that represent the 50th and 95th percentiles, respectively, of the concentrations (with some adjustments) in the U.S. population. It is the first CRM being certified for perchlorate. Measurements leading to the certification of perchlorate were made collaboratively at NIST and CDC using three methods based on liquid or ion chromatography tandem mass spectrometry (LC-MS/MS or IC-MS/MS). Potential sources of bias were analyzed and results were compared for the three methods. Perchlorate in SRM 3668 Level I urine was certified to be 2.70 μg L−1 ± 0.21 μg L−1, and for SRM 3668 Level II urine, the certified value is 13.47 μg L−1 ± 0.96 μg L−1. PMID:22850897

  1. Specific adsorption of perchlorate anions on Pt{hkl} single crystal electrodes.

    Science.gov (United States)

    Attard, Gary A; Brew, Ashley; Hunter, Katherine; Sharman, Jonathan; Wright, Edward

    2014-07-21

    The voltammetry of Pt{111}, Pt{100}, Pt{110} and Pt{311} single crystal electrodes as a function of perchloric acid concentration (0.05-2.00 M) has been studied in order to test the assertion made in recent reports by Watanabe et al. that perchlorate anions specifically adsorb on polycrystalline platinum. Such an assertion would have significant ramifications for our understanding of electrocatalytic processes at platinum surfaces since perchlorate anions at low pH have classically been assumed not to specifically adsorb. For Pt{111}, it is found that OHad and electrochemical oxide states are both perturbed significantly as perchloric acid concentration is increased. We suggest that this is due to specific adsorption of perchlorate anions competing with OHad for adsorption sites. The hydrogen underpotential deposition (H UPD) region of Pt{111} however remains unchanged although evidence for perchlorate anion decomposition to chloride on Pt{111} is reported. In contrast, for Pt{100} no variation in the onset of electrochemical oxide formation is found nor any shift in the potential of the OHad state which normally results from the action of specifically adsorbing anions. This suggests that perchlorate anions are non-specifically adsorbed on this plane although strong changes in all H UPD states are observed as perchloric acid concentration is increased. This manifests itself as a redistribution of charge from the H UPD state situated at more positive potential to the one at more negative potential. For Pt{110} and Pt{311}, marginal changes in the onset of electrochemical oxide formation are recorded, associated with specific adsorption of perchlorate. Specific adsorption of perchlorate anions on Pt{111} is deleterious to electrocatalytic activity in relation to the oxygen reduction reaction (ORR) as measured using a rotating disc electrode (RDE) in a hanging meniscus configuration. This study supports previous work suggesting that a large component of the ORR

  2. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  3. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha;

    2015-01-01

    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p<0.0001) or...

  4. Calcium Calculator

    Science.gov (United States)

    ... Latvia - Lebanon - Libya - Lithuania - Luxembourg - Macedonia, Republic of - Malaysia - Malta - Mexico - Moldova - Morocco - Netherlands - New Zealand - Nigeria - ... and Statistics Popular content Calcium content of common foods What is Osteoporosis? The Board Introduction to Bone ...

  5. Ion Chromatographic Determination of low level Perchlorate in Natural Waters

    International Nuclear Information System (INIS)

    Perchlorate (ClO4-) is a persistent contaminant of drinking-, surface-, and ground-water, and of soils. Possible contributions of ClO4- contamination are the military, the space program, and supporting industries and fertilizers. Perchlorate has long been known to have a negative effect on the thyroid gland. It has been added to the United States Environmental Protection Agency's (EPA) Contaminant candidate List (CCL) in 1998, so that ClO4 can be regulated at a concentration safe to humans. This paper describes the determination of trace level ClO4- in various matrices utilizing ion chromatographic method. The method utilizes a Dionex IonPac AS11 column with suppressed conductivity detection, 1500ul sample loop, and a 100 mN NaOH eluent at a flow rate of 1.0ml/min. These parameters allow a method detection limit (MDL) of 0.277ug/1 and a short retention time of 8 minutes. A quality control, proficiency testing samples from the EPA and a number of environmental samples from New York State (ground water) and California (ground and surface waters) were analyzed by this technique. Concentrations measured were in the range of 1.9-217 ug/1. No evidence of ClO4- was found in various commonly used fertilizers. (author)

  6. Extraction of scandium by benzoylantipyrine from chloride-perchlorate solutions

    International Nuclear Information System (INIS)

    Distribution of scandium complexes in case of extraction by benzoyl-4-antipyrine (BANT) in chloroform from aqueous chloride-perchlorate solutions, depending on extraction, perchlorate-ion and salting out agents concentration, was studied. It has been ascertained that scandium distribution factor is nearly 50 at NaClO4 and BANT concentrations equal to 2 and 0.1 mol/l respectively. Introduction of salting out agents (NaCl, CaCl2) and HCl at a constant content of NaClO4 (0.5 mol/l) increases noticeably scandium extraction. For 0.1 mol/l BANT solution in chloroform the extraction capacity in terms of scandium makes up 1.26 g/l. The optimal conditions for the element extraction have been found, the composition of the complex extracted has been ascertained (Sc:BANT:ClO4- = 1:3:3) and extraction mechanism has been suggested. Influence of interfering elements on scandium distribution factor was studied

  7. The relationship between perchlorate in drinking water and cord blood thyroid hormones: First experience from Iran

    Directory of Open Access Journals (Sweden)

    Ashraf Javidi

    2015-01-01

    Full Text Available Background: Considering the controversial information regarding the effects of perchlorate on thyroid function of high risk population as neonates, and given the high prevalence rate of thyroid disorders specially congenital hypothyroidism in our region, this study aims to investigate for the first time in Iran, the relationship between drinking groundwater perchlorate and cord blood thyroid hormones level in an industrial region. Methods: In this cross-sectional study, drinking groundwater perchlorate level of rural areas of Zarinshahr, Isfahan was measured. Simultaneously, cord blood level of thyroid hormones of neonates born in the studied region was measured. Thyroid function test of neonates in regions with low and high perchlorate level were compared. Results: In this study, 25 tap water samples were obtained for perchlorate measurement. Level of cord blood thyroid stimulating hormone (TSH, T4 and T3 of 25 neonates were measured. Mean (standard deviation of perchlorate, TSH, T4 and T3 was 3.59 (5.10 μg/l, 7.81 (4.14 mIU/m, 6.06 (0.85 mg/dl, and 63.46 (17.53 mg/dl, respectively. Mean levels of thyroid function tests were not different in low ( 0.05. Conclusions: Perchlorate did not appear to be related to thyroid function of neonates in the studied industrial region. It seems that iodine status of the regions, as well as other environmental contaminants and genetic background, could impact on its relation with thyroid function of neonates.

  8. A bioassay for the detection of perchlorate in the ppb range.

    Science.gov (United States)

    Heinnickel, Mark; Smith, Stephen C; Koo, Jonathan; O'Connor, Susan M; Coates, John D

    2011-04-01

    A bioassay for the determination of ppb (μg·L(-1)) concentrations of perchlorate has been developed and is described herein. The assay uses the enzyme perchlorate reductase (PR) from the perchlorate-reducing organism Dechloromonas agitata in purified and partially purified forms to detect perchlorate. The redox active dye phenazine methosulfate (PMS) is shown to efficiently shuttle electrons to PR from NADH. Perchlorate can be determined indirectly by monitoring NADH oxidization by PR. To lower the detection limit, we have shown that perchlorate can be concentrated on a solid-phase extraction (SPE) column that is pretreated with the cation decyltrimethylammonium bromide (DTAB). Perchlorate is eluted from these columns with a solution of 2 M NaCl and 200 mM morpholine propane sulfonic acid (MOPS, pH 12.5). By washing these columns with 15 mL of 2.5 mM DTAB and 15% acetone, contaminating ions, such as chlorate and nitrate, are removed without affecting the bioassay. Because of the effect of complex matrices on the SPE columns, the method of standard additions is used to analyze tap water and groundwater samples. The efficacy of the developed bioassay was demonstrated by analyzing samples from 2-17000 ppb in deionized lab water, tap water, and contaminated groundwater. PMID:21384912

  9. Microbial community analysis of perchlorate-reducing cultures growing on zero-valent iron

    International Nuclear Information System (INIS)

    Anaerobic microbial mixed cultures demonstrated its ability to completely remove perchlorate in the presence of zero-valent iron. In order to understand the major microbial reaction in the iron-supported culture, community analysis comprising of microbial fatty acids and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) techniques was performed for perchlorate reducing cultures. Analysis of fatty acid methyl esters (FAMEs) and subsequent principal component analysis (PCA) showed clear distinctions not only between iron-supported perchlorate reducing culture and seed bacteria, but also among perchlorate-reducing cultures receiving different electron donors. The DGGE pattern targeting the chlorite dismutase (cld) gene showed that iron-supported perchlorate reducing culture is similar to hydrogen-fed cultures as compared to acetate-fed culture. The phylogenetic tree suggested that the dominant microbial reaction may be a combination of the autotrophic and heterotrophic reduction of perchlorate. Both molecular and chemotaxonomic experimental results support further understanding in the function of zero-valent iron as an adequate electron source for enhancing the microbial perchlorate reduction in natural and engineered systems.

  10. Calcium pyrophosphate arthritis

    Science.gov (United States)

    Calcium pyrophosphate dihydrate deposition disease; CPPD disease; Acute CPPD arthritis; Pseudogout ... Calcium pyrophosphate arthritis is caused by the collection of salt called calcium pyrophosphate dihydrate (CPPD). The buildup ...

  11. Evidence for Perchlorates and the Origin of Chlorinated Hydrocarbons Detected by SAM at the Rocknest Aeolian Deposit in Gale Crater

    Science.gov (United States)

    Glavin, Daniel P.; Freissinet, Caroline; Miller, Kristen E.; Eigenbrode, Jennifer L.; Brunner, Anna E.; Buch, Arnaud; Sutter, Brad; Archer, P. Douglas, Jr.; Atreya, Sushil K.; Brinckerhoff, William B.; Cabane, Michel; Coll, Patrice; Conrad, Pamela G.; Coscia, David; Dworkin, Jason P.; Franz, Heather B.; Grotzinger, John P.; Leshin, Laurie A.; Martin, Mildred G.; McKay, Christopher; Ming, Douglas W.; Navarro-Gonzalez, Rafael; Pavlov, Alexander; Steele, Andrew; Summons, Roger E.; Szopa, Cyril; Teinturier, Samuel; Mahaffy, Paul R.

    2013-01-01

    A single scoop of the Rocknest aeolian deposit was sieved (less than 150 micrometers), and four separate sample portions, each with a mass of approximately 50 mg, were delivered to individual cups inside the Sample Analysis at Mars (SAM) instrument by the Mars Science Laboratory rover's sample acquisition system. The samples were analyzed separately by the SAM pyrolysis evolved gas and gas chromatograph mass spectrometer analysis modes. Several chlorinated hydrocarbons including chloromethane, dichloromethane, trichloromethane, a chloromethylpropene, and chlorobenzene were identified by SAM above background levels with abundances of approximately 0.01 to 2.3 nmol. The evolution of the chloromethanes observed during pyrolysis is coincident with the increase in O2 released from the Rocknest sample and the decomposition of a product of N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA), a chemical whose vapors were released from a derivatization cup inside SAM. The best candidate for the oxychlorine compounds in Rocknest is a hydrated calcium perchlorate (Ca(ClO4)2·nH2O), based on the temperature release of O2 that correlates with the release of the chlorinated hydrocarbons measured by SAM, although other chlorine-bearing phases are being considered. Laboratory analog experiments suggest that the reaction of Martian chlorine from perchlorate decomposition with terrestrial organic carbon from MTBSTFA during pyrolysis can explain the presence of three chloromethanes and a chloromethylpropene detected by SAM. Chlorobenzene may be attributed to reactions of Martian chlorine released during pyrolysis with terrestrial benzene or toluene derived from 2,6-diphenylphenylene oxide (Tenax) on the SAM hydrocarbon trap. At this time we do not have definitive evidence to support a nonterrestrial carbon source for these chlorinated hydrocarbons, nor do we exclude the possibility that future SAM analyses will reveal the presence of organic compounds native to the

  12. Genetic factors that might lead to different responses in individuals exposed to perchlorate.

    Science.gov (United States)

    Scinicariello, Franco; Murray, H Edward; Smith, Lester; Wilbur, Sharon; Fowler, Bruce A

    2005-11-01

    Perchlorate has been detected in groundwater in many parts of the United States, and recent detection in vegetable and dairy food products indicates that contamination by perchlorate is more widespread than previously thought. Perchlorate is a competitive inhibitor of the sodium iodide symporter, the thyroid cell-surface protein responsible for transporting iodide from the plasma into the thyroid. An estimated 4.3% of the U.S. population is subclinically hypothyroid, and 6.9% of pregnant women may have low iodine intake. Congenital hypothyroidism affects 1 in 3,000 to 1 in 4,000 infants, and 15% of these cases have been attributed to genetic defects. Our objective in this review is to identify genetic biomarkers that would help define subpopulations sensitive to environmental perchlorate exposure. We review the literature to identify genetic defects involved in the iodination process of the thyroid hormone synthesis, particularly defects in iodide transport from circulation into the thyroid cell, defects in iodide transport from the thyroid cell to the follicular lumen (Pendred syndrome), and defects of iodide organification. Furthermore, we summarize relevant studies of perchlorate in humans. Because of perchlorate inhibition of iodide uptake, it is biologically plausible that chronic ingestion of perchlorate through contaminated sources may cause some degree of iodine discharge in populations that are genetically susceptible to defects in the iodination process of the thyroid hormone synthesis, thus deteriorating their conditions. We conclude that future studies linking human disease and environmental perchlorate exposure should consider the genetic makeup of the participants, actual perchlorate exposure levels, and individual iodine intake/excretion levels. PMID:16263499

  13. Perchlorate Exposure Reduces Primordial Germ Cell Number in Female Threespine Stickleback

    Science.gov (United States)

    Petersen, Ann M.; Earp, Nathanial C.; Redmond, Mandy E.; Postlethwait, John H.; von Hippel, Frank A.; Buck, C. Loren; Cresko, William A.

    2016-01-01

    Perchlorate is a common aquatic contaminant that has long been known to affect thyroid function in vertebrates, including humans. More recently perchlorate has been shown to affect primordial sexual differentiation in the aquatic model fishes zebrafish and threespine stickleback, but the mechanism has been unclear. Stickleback exposed to perchlorate from fertilization have increased androgen levels in the embryo and disrupted reproductive morphologies as adults, suggesting that perchlorate could disrupt the earliest stages of primordial sexual differentiation when primordial germ cells (PGCs) begin to form the gonad. Female stickleback have three to four times the number of PGCs as males during the first weeks of development. We hypothesized that perchlorate exposure affects primordial sexual differentiation by reducing the number of germ cells in the gonad during an important window of stickleback sex determination at 14–18 days post fertilization (dpf). We tested this hypothesis by quantifying the number of PGCs at 16 dpf in control and 100 mg/L perchlorate-treated male and female stickleback. Perchlorate exposure from the time of fertilization resulted in significantly reduced PGC number only in genotypic females, suggesting that the masculinizing effects of perchlorate observed in adult stickleback may result from early changes to the number of PGCs at a time critical for sex determination. To our knowledge, this is the first evidence of a connection between an endocrine disruptor and reduction in PGC number prior to the first meiosis during sex determination. These findings suggest that a mode of action of perchlorate on adult reproductive phenotypes in vertebrates, including humans, such as altered fecundity and sex reversal or intersex gonads, may stem from early changes to germ cell development. PMID:27383240

  14. Perchlorate Exposure Reduces Primordial Germ Cell Number in Female Threespine Stickleback.

    Directory of Open Access Journals (Sweden)

    Ann M Petersen

    Full Text Available Perchlorate is a common aquatic contaminant that has long been known to affect thyroid function in vertebrates, including humans. More recently perchlorate has been shown to affect primordial sexual differentiation in the aquatic model fishes zebrafish and threespine stickleback, but the mechanism has been unclear. Stickleback exposed to perchlorate from fertilization have increased androgen levels in the embryo and disrupted reproductive morphologies as adults, suggesting that perchlorate could disrupt the earliest stages of primordial sexual differentiation when primordial germ cells (PGCs begin to form the gonad. Female stickleback have three to four times the number of PGCs as males during the first weeks of development. We hypothesized that perchlorate exposure affects primordial sexual differentiation by reducing the number of germ cells in the gonad during an important window of stickleback sex determination at 14-18 days post fertilization (dpf. We tested this hypothesis by quantifying the number of PGCs at 16 dpf in control and 100 mg/L perchlorate-treated male and female stickleback. Perchlorate exposure from the time of fertilization resulted in significantly reduced PGC number only in genotypic females, suggesting that the masculinizing effects of perchlorate observed in adult stickleback may result from early changes to the number of PGCs at a time critical for sex determination. To our knowledge, this is the first evidence of a connection between an endocrine disruptor and reduction in PGC number prior to the first meiosis during sex determination. These findings suggest that a mode of action of perchlorate on adult reproductive phenotypes in vertebrates, including humans, such as altered fecundity and sex reversal or intersex gonads, may stem from early changes to germ cell development.

  15. Detoxification of PAX-21 ammunitions wastewater by zero-valent iron for microbial reduction of perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Se Chang; Cha, Daniel K. [Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716 (United States); Kim, Byung J. [U.S. Army Engineer Research and Development Center, Champaign, IL 61826-9005 (United States); Oh, Seok-Young, E-mail: quartzoh@ulsan.ac.kr [Department of Civil and Environmental Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of)

    2011-08-30

    Highlights: {yields} Ammonium perchlorate, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitroanisole (DNAN) are the major constituents of PAX-21. {yields} DNAN is identified as the primary toxicant responsible for inhibiting the activity of perchlorate reducing bacteria. {yields} Iron treatment not only removes energetic compounds but also eliminates the toxic constituents that inhibit the subsequent microbial process. - Abstract: US Army and the Department of Defense (DoD) facilities generate perchlorate (ClO{sub 4}{sup -}) from munitions manufacturing and demilitarization processes. Ammonium perchlorate is one of the main constituents in Army's new main charge melt-pour energetic, PAX-21. In addition to ammonium perchlorate, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitroanisole (DNAN) are the major constituents of PAX-21. In order to evaluate microbial perchlorate reduction as a practical option for the treatment of perchlorate in PAX-21 wastewater, we conducted biodegradation experiments using glucose as the primary sources of electrons and carbon. Batch experiments showed that negligible perchlorate was removed in microbial reactors containing PAX-21 wastewater while control bottles containing seed bacteria and glucose rapidly and completely removed perchlorate. These results suggested that the constituents in PAX-21 wastewater may be toxic to perchlorate reducing bacteria. A series of batch toxicity test was conducted to identify the toxic constituents in PAX-21 and DNAN was identified as the primary toxicant responsible for inhibiting the activity of perchlorate reducing bacteria. It was hypothesized that pretreatment of PAX-21 by zero-valent iron granules will transform toxic constituents in PAX-21 wastewater to non-toxic products. We observed complete reduction of DNAN to 2,4-diaminoanisole (DAAN) and RDX to formaldehyde in abiotic iron reduction study. After a 3-day acclimation period, perchlorate in iron-treated PAX-21

  16. Detoxification of PAX-21 ammunitions wastewater by zero-valent iron for microbial reduction of perchlorate

    International Nuclear Information System (INIS)

    Highlights: → Ammonium perchlorate, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitroanisole (DNAN) are the major constituents of PAX-21. → DNAN is identified as the primary toxicant responsible for inhibiting the activity of perchlorate reducing bacteria. → Iron treatment not only removes energetic compounds but also eliminates the toxic constituents that inhibit the subsequent microbial process. - Abstract: US Army and the Department of Defense (DoD) facilities generate perchlorate (ClO4-) from munitions manufacturing and demilitarization processes. Ammonium perchlorate is one of the main constituents in Army's new main charge melt-pour energetic, PAX-21. In addition to ammonium perchlorate, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitroanisole (DNAN) are the major constituents of PAX-21. In order to evaluate microbial perchlorate reduction as a practical option for the treatment of perchlorate in PAX-21 wastewater, we conducted biodegradation experiments using glucose as the primary sources of electrons and carbon. Batch experiments showed that negligible perchlorate was removed in microbial reactors containing PAX-21 wastewater while control bottles containing seed bacteria and glucose rapidly and completely removed perchlorate. These results suggested that the constituents in PAX-21 wastewater may be toxic to perchlorate reducing bacteria. A series of batch toxicity test was conducted to identify the toxic constituents in PAX-21 and DNAN was identified as the primary toxicant responsible for inhibiting the activity of perchlorate reducing bacteria. It was hypothesized that pretreatment of PAX-21 by zero-valent iron granules will transform toxic constituents in PAX-21 wastewater to non-toxic products. We observed complete reduction of DNAN to 2,4-diaminoanisole (DAAN) and RDX to formaldehyde in abiotic iron reduction study. After a 3-day acclimation period, perchlorate in iron-treated PAX-21 wastewater was rapidly decreased to

  17. Calcium and bones

    Science.gov (United States)

    Bone strength and calcium ... calcium (as well as phosphorus) to make healthy bones. Bones are the main storage site of calcium in ... your body does not absorb enough calcium, your bones can get weak or will not grow properly. ...

  18. Get Enough Calcium

    Science.gov (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  19. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  20. Effect of nitrate, acetate, and hydrogen on native perchlorate-reducing microbial communities and their activity in vadose soil.

    Science.gov (United States)

    Nozawa-Inoue, Mamie; Jien, Mercy; Yang, Kun; Rolston, Dennis E; Hristova, Krassimira R; Scow, Kate M

    2011-05-01

    The effect of nitrate, acetate, and hydrogen on native perchlorate-reducing bacteria (PRB) was examined by conducting microcosm tests using vadose soil collected from a perchlorate-contaminated site. The rate of perchlorate reduction was enhanced by hydrogen amendment and inhibited by acetate amendment, compared with unamendment. Nitrate was reduced before perchlorate in all amendments. In hydrogen-amended and unamended soils, nitrate delayed perchlorate reduction, suggesting that the PRB preferentially use nitrate as an electron acceptor. In contrast, nitrate eliminated the inhibitory effect of acetate amendment on perchlorate reduction and increased the rate and the extent, possibly because the preceding nitrate reduction/denitrification decreased the acetate concentration that was inhibitory to the native PRB. In hydrogen-amended and unamended soils, perchlorate reductase gene (pcrA) copies, representing PRB densities, increased with either perchlorate or nitrate reduction, suggesting that either perchlorate or nitrate stimulates the growth of the PRB. In contrast, in acetate-amended soil pcrA increased only when perchlorate was depleted: a large portion of the PRB may have not utilized nitrate in this amendment. Nitrate addition did not alter the distribution of the dominant pcrA clones in hydrogen-amended soil, likely because of the functional redundancy of PRB as nitrate-reducers/denitrifiers, whereas acetate selected different pcrA clones from those with hydrogen amendment. PMID:21284679

  1. A rapid and simple method for the separation of TBP-dodecane by perchloric acid

    International Nuclear Information System (INIS)

    Organic solvents, including TBP etc., are widely used as an extractant, and treated and disposed by storage, incineration, and absorption into absorbent after they were used. Any of those methods does not aim at recycling of solvents, treating concurrently the extractant and the diluent without separating them. In this paper, a test is reported on the TBP-dodecane separation by perchloric acid for a separation test of the diluent from the extractant as a first step toward recycling. Basically this separation method is already reported by P. Mark et al. as a method for the analysis of TBP, but it requires a large amount of perchloric acid. With a further detailed study of the perchloric acid effects on the TBP-dodecane separation, it was made clear that the separation is possible by adding a fixed amount of TBP contacted with perchloric acid to the TBP-dodecane solvent. In this paper, its outline is presented. (author)

  2. ANALYSIS OF HYDROPONIC FERTILIZER MATRIXES FOR PERCHLORATE: COMPARISON OF ANALYTICAL TECHNIQUES

    Science.gov (United States)

    Seven retail hydroponic nitrate fertilizer products, two liquid and five solid, were comparatively analyzed for the perchlorate anion (ClO4-) by ion chromatography (IC) with suppressed conductivity detection, complexation electrospray ionization mass spectrometry (cESI-MS), norma...

  3. Radioiodine tracers as useful tools in studies of thyrotoxic effects of exogenous bromide and perchlorate ions

    International Nuclear Information System (INIS)

    With the use of 125I and 131I radionuclides, we followed the effects of exogenous bromide and perchlorate ions on the metabolism of iodine and of thyroid hormone in the rat. The presumed thyrotoxic effects of bromide and perchlorate have been confirmed and quantified. Correct assay conditions for the radiometric determination of the enzyme activity of thyroid peroxidase (TPO) have been established. The use of the adapted radiometric assay revealed a divergent influence of bromide and perchlorate ions on the TPO activity in the rat thyroids. Excessive bromide exerted a biphasic effect, depending on the extent of bromide intake in the animals. In contrast, in all the rats that were administered with high amounts of perchlorate were found elevated TPO activities. (author)

  4. On the stability of perchlorate ions against reductive attacks in electrochemical systems and in the environment

    Directory of Open Access Journals (Sweden)

    GYŐZŐ G. LÁNG

    2011-08-01

    Full Text Available The problems related to the electrochemical/electrocatalytic stability of perchlorate ions are reviewed in the light of recent experimental results. The electrocatalytic, catalytic, and electrochemical reduction processes are presented and the links between them are outlined. Some possible mechanisms of the complicated reduction processes are discussed. Various methods for the detection of reduction process are presented, e.g. voltammetry, impedance spectroscopy, and radiotracer methods. Environmental aspects and some methods for perchlorate removal and wastewater treatment are briefly summarized.

  5. The perchlorate discharge test with 123I for the diagnosis of the Pendred syndrome in children

    International Nuclear Information System (INIS)

    The method for the diagnosis of the Pendred Syndrome in children by the Perchlorate discharge test using 123I is described. The older child, who has the Pendred Syndrome and the obligatory hearing deficit, frequently has neither a goitre nor hypothyroidism, but other investigations (bone growth, scars and function tests) can also show changes. However a more certain diagnosis of this disorder in children is possible by the perchlorate discharge test using 123I. (orig.)

  6. Behavioral response of dissimilatory perchlorate-reducing bacteria to different electron acceptors

    OpenAIRE

    Sun, Yvonne; Gustavson, Ruth L.; Ali, Nadia; Weber, Karrie A.; Westphal, Lacey L.; Coates, John D.

    2009-01-01

    The response behavior of three dissimilatory perchlorate-reducing bacteria to different electron acceptors (nitrate, chlorate, and perchlorate) was investigated with two different assays. The observed response was species-specific, dependent on the prior growth conditions, and was inhibited by oxygen. We observed attraction toward nitrate when Dechloromonas aromatica strain RCB and Azospira suillum strain PS were grown with nitrate. When D. aromatica and Dechloromonas agitata strain CKB were ...

  7. Perchlorate in dust fall and indoor dust in Malta: An effect of fireworks.

    Science.gov (United States)

    Vella, Alfred J; Chircop, Cynthia; Micallef, Tamara; Pace, Colette

    2015-07-15

    We report on the presence of perchlorate in the settleable dust of Malta, a small central Mediterranean island. Both dust fall collected directly as it precipitated from atmosphere over a period of one month and deposited indoor dust from domestic residences were studied. Perchlorate was determined by ion chromatography of water extracts of the collected dusts. Dust fall was collected from 43 towns during 2011 to 2013 and indoor dust was sampled from homes in the same localities. Perchlorate was detected in 108 of 153 samples of dust fall (71%) and in 28 of 37 indoor dust samples (76%). Detectable perchlorate in dust fall ranged from 0.52μgg(-1) to 561μgg(-1) with a median value of 6.2μgg(-1); in indoor dust, levels were from 0.79μgg(-1) to 53μgg(-1) with a median value of 7.8μgg(-1), the highest recorded anywhere to date. Statistical analysis suggested that there was no significant difference in perchlorate content of indoor dust and dust fall. Perchlorate levels in dust fall escalate during the summer in response to numerous religious feasts celebrated with fireworks and perchlorate persists at low μgg(-1) concentrations for several months beyond the summer festive period. In Malta, perchlorate derives exclusively from KClO4, imported for fireworks manufacture. Its residue in dust presents an exposure risk to the population, especially via ingestion by hand to mouth transfer. Our results suggest that wherever intensive burning of fireworks takes place, the environmental impact may be much longer lived than realised, mainly due to re-suspension and deposition of contaminated settled dust in the urban environment. PMID:25828411

  8. Microbial redox processes in deep subsurface environments and the potential application of (perchlorate in oil reservoirs

    Directory of Open Access Journals (Sweden)

    Martin G Liebensteiner

    2014-09-01

    Full Text Available The ability of microorganisms to thrive under oxygen-free conditions in subsurface environments relies on the enzymatic reduction of oxidized elements, such as sulfate, ferric iron or CO2, coupled to the oxidation of inorganic or organic compounds. A broad phylogenetic and functional diversity of microorganisms from subsurface environments has been described using isolation-based and advanced molecular ecological techniques. The physiological groups reviewed here comprise iron-, manganese- and nitrate-reducing microorganisms. In the context of recent findings also the potential of chlorate and perchlorate [jointly termed (perchlorate] reduction in oil reservoirs will be discussed. Special attention is given to elevated temperatures that are predominant in the deep subsurface. Microbial reduction of (perchlorate is a thermodynamically favorable redox process, also at high temperature. However, knowledge about (perchlorate reduction at elevated temperatures is still scarce and restricted to members of the Firmicutes and the archaeon Archaeoglobus fulgidus. By analyzing the diversity and phylogenetic distribution of functional genes in (metagenome databases and combining this knowledge with extrapolations to earlier-made physiological observations we speculate on the potential of (perchlorate reduction in the subsurface and more precisely oil fields. In addition, the application of (perchlorate for bioremediation, souring control and microbial enhanced oil recovery are addressed.

  9. Preliminary analyses for perchlorate in selected natural materials and their derivative products

    Science.gov (United States)

    Orris, G.J.; Harvey, G.J.; Tsui, D.T.; Eldrige, J.E.

    2003-01-01

    Increasing concern about sources of perchlorate contamination in ground and surface waters has led to interest in identifying potential sources of natural perchlorate and products derived from these natural sources. To date, most perchlorate found in ground and surface waters has been attributed to its major uses as an oxidizer in solid propellants for rockets, in fireworks and other explosives, and a variety of other uses of man-made perchlorate salts. However, perchlorate found in the soils, surface water, and ground water of some locations cannot be linked to an anthropogenic source. This paper contains preliminary data on the detection and non-detection of perchlorate in a variety of natural materials and their products, including some fertilizer materials. These data were previously presented at two conferences; once in poster session and once orally (Harvey and others, 1999; Orris and others, 2000). Although the results presented here are included in a journal article awaiting publication, the lack of public information on this topic has led to repeated requests for the data used as the basis for our presentations in 1999 and 2000.

  10. A screened hybrid density functional study on energetic complexes: Cobalt, nickel and copper carbohydrazide perchlorates

    International Nuclear Information System (INIS)

    Graphical abstract: The molecular geometry, electronic structure, infrared spectra, and heats of reaction and formation of cobalt and nickel tris(carbohydrazide) perchlorates as well as copper bis(carbohydrazide) perchlorate are investigated using the HSE screened hybrid density functional. The metal-ligand interaction, thermal stability, and red-shift of the amino stretching vibrations of these complexes are also discussed. Moreover, it is found there is a relationship between the energy gap and impact sensitivity. - Abstract: The molecular geometry, electronic structure, infrared spectra and thermochemical properties of cobalt and nickel tris(carbohydrazide) perchlorates (CoCP and NiCP) as well as copper bis(carbohydrazide) perchlorate (CuCP) were investigated using the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid density functional. The results show that both perchlorate ions coordinate with the copper atom, and the interactions between copper and perchlorate are ionic, whereas all the metal-carbohydrazide interactions are covalent. Due to the delocalization from the σN-H bond orbital to the n*M antibond orbital, the amino stretching vibrations of these complexes show considerable red-shift compared with those of free carbohydrazide ligand. The calculated heats of reaction and formation indicate that the formations of these complexes are exothermic, and the order of their thermal stability is NiCP > CoCP > CuCP. These agree well with the experimental results. Finally, we find that there is a relationship between the energy gap and impact sensitivity.

  11. Mechanistic Studies on the Radiolytic Decomposition of Perchlorates on the Martian Surface

    Science.gov (United States)

    Turner, Andrew M.; Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-04-01

    Perchlorates—inorganic compounds carrying the perchlorate ion ({{ClO}}4{}-)—were discovered at the north polar landing site of the Phoenix spacecraft and at the southern equatorial landing site of the Curiosity Rover within the Martian soil at levels of 0.4-0.6 wt%. This study explores in laboratory experiments the temperature-dependent decomposition mechanisms of hydrated perchlorates—namely magnesium perchlorate hexahydrate (Mg(ClO4)2·6H2O)—and provides yields of the oxygen-bearing species formed in these processes at Mars-relevant surface temperatures from 165 to 310 K in the presence of galactic cosmic-ray particles (GCRs). Our experiments reveal that the response of the perchlorates to the energetic electrons is dictated by the destruction of the perchlorate ion ({{ClO}}4{}-) and the inherent formation of chlorates ({{ClO}}3{}-) plus atomic oxygen (O). Isotopic substitution experiments reveal that the oxygen is released solely from the perchlorate ion and not from the water of hydration (H2O). As the mass spectrometer detects only molecular oxygen (O2) and no atomic oxygen (O), atomic oxygen recombines to molecular oxygen within the perchlorates, with the overall yield of molecular oxygen increasing as the temperature drops from 260 to 160 K. Absolute destruction rates and formation yields of oxygen are provided for the planetary modeling community.

  12. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.

    1984-01-01

    Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture, exhausti

  13. High-nitrogen-based pyrotechnics: perchlorate-free red- and green-light illuminants based on 5-aminotetrazole.

    Science.gov (United States)

    Sabatini, Jesse J; Moretti, Jared D

    2013-09-16

    Prototype testing of perchlorate-free hand-held signal illuminants for the US Army's M126 A1 red-star and M195 green-star parachute illuminants are described. Although previous perchlorate-free variants for these items have been developed based on high-nitrogen compounds that are not readily available, the new formulations consist of anhydrous 5-aminotetrazole as the suitable perchlorate replacement. Compared to the perchlorate-containing control, the disclosed illuminants exhibited excellent stabilities toward various ignition stimuli and had excellent pyrotechnic performance. The illuminants are important from both military and civil fireworks perspectives, as the perchlorate-free nature of the illuminants adequately address environmental concerns associated with perchlorate-containing red- and green-light-emitting illuminants. PMID:23950104

  14. Inhibition of microbial sulfate reduction in a flow-through column system by (per)chlorate treatment

    OpenAIRE

    Anna eEngelbrektson; Christopher eHubbard; Lauren eTom; Aaron eBOUSSINA; Yong Tae eJin; Hayden eWong; Yvette Marisa Piceno; Hans Karl Carlson; Mark eConrad; Andersen, Gary L.; Coates, John D.

    2014-01-01

    Microbial sulfate reduction is a primary cause of oil reservoir souring. Here we show that amendment with chlorate or perchlorate [collectively (per)chlorate] potentially resolves this issue. Triplicate packed columns inoculated with marine sediment were flushed with coastal water amended with yeast extract and one of nitrate, chlorate, or perchlorate. Results showed that although sulfide production was dramatically reduced by all treatments, effluent sulfide was observed in the nitrate (10 m...

  15. High-performing red-light-emitting pyrotechnic illuminants through the use of perchlorate-free materials.

    Science.gov (United States)

    Moretti, Jared D; Sabatini, Jesse J; Poret, Jay C

    2014-07-01

    The development of perchlorate-free M662 40 mm illuminating pyrotechnic compositions is described. On the bases of cost, performance, and sensitivity, potassium periodate was determined to be most effective potassium perchlorate replacement in the compositions tested. The optimal periodate-based composition exceeded the performance of the perchlorate-containing control, exhibited low sensitivity values to impact, friction, and electrostatic discharge, and had high thermal onset temperatures. PMID:24939042

  16. Study of microbial perchlorate reduction: Considering of multiple pH, electron acceptors and donors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xing [Key Laboratory of Water Pollution Control and Recycling (Shandong), School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Gao, Baoyu, E-mail: bygao@sdu.edu.cn [Key Laboratory of Water Pollution Control and Recycling (Shandong), School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Jin, Bo [School of Chemical Engineering, The University of Adelaide, Adelaide SA 5005,Australia (Australia); Zhen, Hu [Key Laboratory of Water Pollution Control and Recycling (Shandong), School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Wang, Xiaoyi [CSIRO Land and Water, Gate 5, Waite Road, Urrbrae, SA 5064 (Australia); Dai, Ming [School of Chemical Engineering, The University of Adelaide, Adelaide SA 5005,Australia (Australia)

    2015-03-21

    Graphical abstract: Schemes of perchlorate reduction in ClO{sub 4}{sup −}/ClO{sub 3}{sup −}–NO{sub 3}{sup −} e{sup −}acceptor systems. - Highlights: • We created a multiple electron acceptor/donor system for ClO{sub 4}{sup −} reduction. • Nitrate reduction was inhibited when using perchlorate-grown Azospira sp. KJ. • Reduction proceeded as an order of ClO{sub 3}{sup −}, ClO{sub 4}{sup −}and NO{sub 3}{sup −}. • Oxidation of acetate was inhibited by succinate in acetate–succinate series. - Abstract: Bioremediation of perchlorate-cotaminated water by a heterotrophic perchlorate reducing bacterium creates a multiple electron acceptor-donor system. We experimentally determined the perchlorate reduction by Azospira sp. KJ at multiple pH, electron acceptors and donors systems; this was the aim of this study. Perchlorate reduction was drastically inhibited at the pH 6.0, and the maximum reduction of perchlorate by Azospira sp. KJ was observed at pH value of 8.0. Perchlorate reduction was retarded in ClO{sub 4}{sup −}–ClO{sub 3}{sup −}, ClO{sub 4}{sup −}–ClO{sub 3}{sup −}–NO{sub 3}{sup −},and ClO{sub 4}{sup −}–NO{sub 3}{sup −} acceptor systems, while being completely inhibited by the additional O{sub 2} in the ClO{sub 4}{sup −}–O{sub 2} acceptor system. The reduction proceeded as an order of ClO{sub 3}{sup −}, ClO{sub 4}{sup −}, and NO{sub 3}{sup −} in the ClO{sub 4}{sup −}–ClO{sub 3}{sup −}–NO{sub 3}{sup −} system. K{sub S,}v{sub max}, and q{sub max} obtained at different e{sup −} acceptor and donor conditions are calculated as 140.5–190.6 mg/L, 8.7–13.2 mg-perchlorate/L-h, and 0.094–0.16 mg-perchlorate/mg-DW-h, respectively.

  17. Study of microbial perchlorate reduction: Considering of multiple pH, electron acceptors and donors

    International Nuclear Information System (INIS)

    Graphical abstract: Schemes of perchlorate reduction in ClO4−/ClO3−–NO3− e−acceptor systems. - Highlights: • We created a multiple electron acceptor/donor system for ClO4− reduction. • Nitrate reduction was inhibited when using perchlorate-grown Azospira sp. KJ. • Reduction proceeded as an order of ClO3−, ClO4−and NO3−. • Oxidation of acetate was inhibited by succinate in acetate–succinate series. - Abstract: Bioremediation of perchlorate-cotaminated water by a heterotrophic perchlorate reducing bacterium creates a multiple electron acceptor-donor system. We experimentally determined the perchlorate reduction by Azospira sp. KJ at multiple pH, electron acceptors and donors systems; this was the aim of this study. Perchlorate reduction was drastically inhibited at the pH 6.0, and the maximum reduction of perchlorate by Azospira sp. KJ was observed at pH value of 8.0. Perchlorate reduction was retarded in ClO4−–ClO3−, ClO4−–ClO3−–NO3−,and ClO4−–NO3− acceptor systems, while being completely inhibited by the additional O2 in the ClO4−–O2 acceptor system. The reduction proceeded as an order of ClO3−, ClO4−, and NO3− in the ClO4−–ClO3−–NO3− system. KS,vmax, and qmax obtained at different e− acceptor and donor conditions are calculated as 140.5–190.6 mg/L, 8.7–13.2 mg-perchlorate/L-h, and 0.094–0.16 mg-perchlorate/mg-DW-h, respectively

  18. Particle size distribution and perchlorate levels in settled dust from urban roads, parks, and roofs in Chengdu, China.

    Science.gov (United States)

    Li, Yiwen; Shen, Yang; Pi, Lu; Hu, Wenli; Chen, Mengqin; Luo, Yan; Li, Zhi; Su, Shijun; Ding, Sanglan; Gan, Zhiwei

    2016-01-01

    A total of 27 settled dust samples were collected from urban roads, parks, and roofs in Chengdu, China to investigate particle size distribution and perchlorate levels in different size fractions. Briefly, fine particle size fractions (intake is safe to both children and adults in Chengdu, China. However, due to perchlorate mainly existing in fine particles, there is a potential for perchlorate to transfer into surface water and the atmosphere by runoff and wind erosion or traffic emission, and this could act as an important perchlorate pollution source for the indoor environment, and merits further study. PMID:26608047

  19. Americium(3) solvent extraction by oxides of dialkyl(diaryl)[dialkylcarbamoylmethyl]phosphines (CMPO) from perchloric acid solutions

    International Nuclear Information System (INIS)

    Extraction of americium(3) from perchloric acid solutions by CMPO was investigated. It is shown that americium(3) is much more effectively extracted from perchloric acid solutions, than from nitric acid ones, and increase in americium distribution coefficient depends considerably on reagent nature. As a consequence, anomalous aryl effect increases significantly in perchloric acid solutions. The value of anomalous aryl effect depends directly on stoichiometry of extracted complexes in nitric acid and perchloric acid media. Conditions for extractional concentration of americium up to the 100-fold one with small reagent consumption were suggested

  20. Soil Flushing Through a Thick Vadose Zone: Perchlorate Removal Documented at Edwards AFB, California

    Science.gov (United States)

    Battey, T. F.; Shepard, A. J.; Tait, R. J.

    2007-12-01

    There are currently few viable alternatives for perchlorate remediation in the vadose zone, particularly for the relatively thick vadose zones that are typical in the arid southwest where many perchlorate sites occur. Perchlorate in the vadose zone occurs in the form of highly soluble salts that may represent a risk to human or ecological receptors, and may also represent a threat to the underlying groundwater. A soil flushing treatability study was conducted at Edwards Air Force Base in the Mojave Desert of southern California at a site with a 129-foot thick vadose zone consisting primarily of clayey sand. This study utilized an infiltration gallery in conjunction with extraction, treatment, and re-injection of groundwater at the site, which contained perchlorate-contaminated soil and groundwater. The study objective was to evaluate the effectiveness of the infiltration gallery to 1) introduce treated groundwater back into the aquifer and 2) wash the perchlorate from the vadose zone soils to the aquifer. The infiltration gallery consisted of slotted PVC pipes within a highly permeable engineered bed of washed gravel. The initial water introduced into the gallery was amended with potassium bromide tracer. A downhole neutron probe was used to track the movement of the wetting front downward and outward from the gallery. Successive neutron measurements in vertical access tubes revealed that the introduced water reached the 125-foot bottom of the access tubes 14 weeks after the water was introduced into the gallery. The bromide tracer was detected in groundwater immediately below the gallery approximately 1 week later. The infiltration gallery was able to sustain an average flow rate of 2.3 gallons per minute. Prior to infiltration, the perchlorate concentration in groundwater below the gallery was 4,500 µg/L. Approximately 18 weeks after the start of infiltration, a perchlorate spike of 72,400 µg/L was detected below the gallery. The increase in perchlorate

  1. Inhibition of microbial sulfate reduction in a flow-through column system by (perchlorate treatment

    Directory of Open Access Journals (Sweden)

    Anna eEngelbrektson

    2014-06-01

    Full Text Available Microbial sulfate reduction is a primary cause of oil reservoir souring. Here we show that amendment with chlorate or perchlorate [collectively (perchlorate] potentially resolves this issue. Triplicate packed columns inoculated with marine sediment were flushed with coastal water amended with yeast extract and one of nitrate, chlorate, or perchlorate. Results showed that although sulfide production was dramatically reduced by all treatments, effluent sulfide was observed in the nitrate (10 mM treatment after an initial inhibition period. In contrast, no effluent sulfide was observed with (perchlorate (10 mM. Microbial community analyses indicated temporal community shifts and phylogenetic clustering by treatment. Nitrate addition stimulated Xanthomonadaceae and Rhizobiaceae growth, supporting their role in nitrate metabolism. (Perchlorate showed distinct effects on microbial community structure compared with nitrate and resulted in a general suppression of the community relative to the untreated control combined with a significant decrease in sulfate reducing species abundance indicating specific toxicity. Furthermore, chlorate stimulated Pseudomonadaceae and Pseudoalteromonadaceae, members of which are known chlorate respirers, suggesting that chlorate may also control sulfidogenesis by biocompetitive exclusion of sulfate-reduction. Perchlorate addition stimulated Desulfobulbaceae and Desulfomonadaceae, which contain sulfide oxidizing and elemental sulfur-reducing species respectively, suggesting that effluent sulfide concentrations may be controlled through sulfur redox cycling in addition to toxicity and biocompetitive exclusion. Sulfur isotope analyses further support sulfur cycling in the columns, even when sulfide is not detected. This study indicates that (perchlorate show great promise as inhibitors of sulfidogenesis in natural communities and provides insight into which organisms and respiratory processes are involved.

  2. Structure, phase transitions and molecular motions in 4-aminopyridinium perchlorate

    Science.gov (United States)

    Czupinski, O.; Bator, G.; Ciunik, Z.; Jakubas, R.; Medycki, W.; Swiergiel, J.

    2002-09-01

    The crystal structure of the 4-aminopyridinium perchlorate (4-apyH)ClO4 has been determined at 100 K by means of x-ray diffraction as monoclinic, with space group P 21, with Z = 8. The crystal undergoes two structural phase transitions: one of first-order type, reversible, at 241/243 K (on cooling/heating respectively) and one of weakly first-order type, irreversible, at 277 K (on heating). The crystal dynamics is discussed on the basis of the temperature dependence of the 1 H nuclear magnetic resonance second moment (M2) and spin-lattice relaxation time T1. Both phase transitions are interpreted in terms of the changes in the motional state of (4-apyH)+ cations and ClO4- anions. The dielectric dispersion studies disclose a relaxation process over the high-temperature phase (above 241 K) in the audio-frequency region. The dielectric results are described by a Cole-Cole equation. The title crystal reveals pyroelectric properties below 241 K. The ferroelastic domain structure of (4-apyH)ClO4 is observed over the whole temperature range studied.

  3. Structure, phase transitions and molecular motions in 4-aminopyridinium perchlorate

    International Nuclear Information System (INIS)

    The crystal structure of the 4-aminopyridinium perchlorate (4-apyH)ClO4 has been determined at 100 K by means of x-ray diffraction as monoclinic, with space group P 21, with Z=8. The crystal undergoes two structural phase transitions: one of first-order type, reversible, at 241/243 K (on cooling/heating respectively) and one of weakly first-order type, irreversible, at 277 K (on heating). The crystal dynamics is discussed on the basis of the temperature dependence of the 1H nuclear magnetic resonance second moment (M2) and spin-lattice relaxation time T1. Both phase transitions are interpreted in terms of the changes in the motional state of (4-apyH)+ cations and ClO4- anions. The dielectric dispersion studies disclose a relaxation process over the high-temperature phase (above 241 K) in the audio-frequency region. The dielectric results are described by a Cole-Cole equation. The title crystal reveals pyroelectric properties below 241 K. The ferroelastic domain structure of (4-apyH)ClO4 is observed over the whole temperature range studied. (author)

  4. Structure, phase transitions and molecular motions in 4-aminopyridinium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Czupinski, O.; Bator, G.; Ciunik, Z.; Jakubas, R. [Faculty of Chemistry, University of Wroclaw, Wroclaw (Poland); Medycki, W.; Swiergiel, J. [Institute of Molecular Physics, PAS, Poznan (Poland)

    2002-09-16

    The crystal structure of the 4-aminopyridinium perchlorate (4-apyH)ClO{sub 4} has been determined at 100 K by means of x-ray diffraction as monoclinic, with space group P 2{sub 1}, with Z=8. The crystal undergoes two structural phase transitions: one of first-order type, reversible, at 241/243 K (on cooling/heating respectively) and one of weakly first-order type, irreversible, at 277 K (on heating). The crystal dynamics is discussed on the basis of the temperature dependence of the {sup 1}H nuclear magnetic resonance second moment (M{sub 2}) and spin-lattice relaxation time T{sub 1}. Both phase transitions are interpreted in terms of the changes in the motional state of (4-apyH){sup +} cations and ClO{sub 4}- anions. The dielectric dispersion studies disclose a relaxation process over the high-temperature phase (above 241 K) in the audio-frequency region. The dielectric results are described by a Cole-Cole equation. The title crystal reveals pyroelectric properties below 241 K. The ferroelastic domain structure of (4-apyH)ClO{sub 4} is observed over the whole temperature range studied. (author)

  5. Iodine-deficient vegetarians: a hypothetical perchlorate-susceptible population?

    Science.gov (United States)

    Fields, Cheryl; Dourson, Michael; Borak, Jonathan

    2005-06-01

    Recent risk assessments of environmental perchlorate have been subject to much debate. A particular concern is whether appropriate susceptible sub-populations have been identified. Iodine-deficient pregnant women, especially vegetarians, have been proposed as such a potential susceptible sub-population, but there is no evidence of iodine deficiency in the US population and the adequacy of iodine nutrition has not been studied in US vegetarians. To understand the possibility that US vegetarians might be iodine deficient, we reviewed the prevalence, demography, and lifestyle characteristics of US vegetarians as well as the world literature on iodine nutrition in vegetarians. Our findings indicate that strict vegetarians and vegans, who comprise probably less than 0.1% of the US population, have higher education, higher incomes, and healthier lifestyles than the general population. Field studies indicate that vegetarian diets need not lead to iodine deficiency and vegans may suffer excess iodine intake. It is remains uncertain whether there are iodine-deficient vegans or pregnant women in the US. Of more general concern is whether the 10-fold default uncertainty factor is needed for intraspecies (i.e., within human) variability to protect such hypothetical susceptible sub-populations. PMID:15896441

  6. Chlorine-36 abundance in natural and synthetic perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Heikoop, Jeffrey M [Los Alamos National Laboratory; Dale, M [NON LANL; Sturchio, Neil C [UNIV OF ILLIONOIS; Caffee, M [PURDUE UNIV; Belosa, A D [UNIV OF ILLINOIS; Heraty, Jr., L J [UNIV OF ILLINOIS; Bohike, J K [RESTON, VA; Hatzinger, P B [SHAW ENIVIORNMENTAL C0.; Jackson, W A [TEXAS TECH; Gu, B [ORNL

    2009-01-01

    Perchlorate (ClO{sub 4}{sup -}) is ubiquitous in the environment. It occurs naturally as a product of atmospheric photochemical reactions, and is synthesized for military, aerospace, and industrial applications. Nitrate-enriched soils of the Atacama Desert (Chile) contain high concentrations of natural ClO{sub 4}{sup -}; nitrate produced from these soils has been exported worldwide since the mid-1800's for use in agriculture. The widespread introduction of synthetic and agricultural ClO{sub 4}{sup -} into the environment has complicated attempts to understand the geochemical cycle of ClO{sub 4}{sup -}. Natural ClO{sub 4}{sup -} samples from the southwestern United States have relatively high {sup 36}Cl abundances ({sup 36}Cl/Cl = 3,100 x 10{sup -15} to 28,800 x 10{sup -15}), compared with samples of synthetic ({sup 36}Cl/Cl = 0.0 x 10{sup -15} to 40 x 10{sup -15}) and Atacama Desert ({sup 36}Cl/Cl = 0.9 x 10{sup -15} to 590 x 10{sup -15}) ClO{sub 4}{sup -}. These data give a lower limit for the initial {sup 36}Cl abundance of natural ClO{sub 4}{sup -} and provide temporal and other constraints on its geochemical cycle.

  7. Hydrogen oxidation on gold electrode in perchloric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Sustersic, M.G.; Almeida, N.V.; Von Mengershausen, A.E. [Facultad de Ingenieria y Ciencias Economico Sociales, Universidad Nacional de San Luis, 25 de Mayo N 384, 5730 Villa Mercedes, San Luis (Argentina)

    2010-06-15

    The aim of this research is to study the interface gold/perchloric acid solution in presence of hydrogen. The reactive is generated by H{sup +} ion reduction and by saturating the electrolyte with the gaseous H{sub 2}. No evidence of H{sub 2} dissociative adsorption is found. In special conditions, a strongly adsorbed layer is formed from the atoms diffusing from inside of the metal. The mass transport occurs in three ways: the diffusion of H atoms inwards, the diffusion of H atoms back to the surface and the dissolved H{sub 2} diffusion from the bulk electrolyte to the surface. When dissolved H{sub 2} reacts, the reaction is kinetically controlled when the H{sub 2} partial pressure is high, and it is diffusionally controlled when the reactive partial pressure is low. Above 0.7 V, (measured vs. RHE), the (100) plane surface reconstruction lifts, and the rate determining step is the H diffusion towards inside of the metal, and the current suddenly falls. The Hydrogen redox reaction on gold shows reversibility with respect to the potential when the reactives are the H diffusing outwards of the metal and the H{sup +} ion present in the electrolyte. However, the absolute current values of oxidation and reduction are different because the reactive sources are different. (author)

  8. Widespread occurrence of (per)chlorate in the Solar System

    Science.gov (United States)

    Jackson, W. Andrew; Davila, Alfonso F.; Sears, Derek W. G.; Coates, John D.; McKay, Christopher P.; Brundrett, Maeghan; Estrada, Nubia; Böhlke, J. K.

    2015-11-01

    Perchlorate (ClO4-) and chlorate (ClO3-) are ubiquitous on Earth and ClO4- has also been found on Mars. These species can play important roles in geochemical processes such as oxidation of organic matter and as biological electron acceptors, and are also indicators of important photochemical reactions involving oxyanions; on Mars they could be relevant for human habitability both in terms of in situ resource utilization and potential human health effects. For the first time, we extracted, detected and quantified ClO4- and ClO3- in extraterrestrial, non-planetary samples: regolith and rock samples from the Moon, and two chondrite meteorites (Murchison and Fayetteville). Lunar samples were collected by astronauts during the Apollo program, and meteorite samples were recovered immediately after their fall. This fact, together with the heterogeneous distribution of ClO4- and ClO3- within some of the samples, and their relative abundance with respect to other soluble species (e.g., NO3-) are consistent with an extraterrestrial origin of the oxychlorine species. Our results, combined with the previously reported widespread occurrence on Earth and Mars, indicate that ClO4- and ClO3- could be present throughout the Solar System.

  9. Microbial Community Structure during Nitrate and Perchlorate Reduction in Ion-exchange Brine Using the Hydrogen-based membrane Biofilm Reactor (MBIR)

    Science.gov (United States)

    Detoxification of perchlorate by microbial communities under denitrifying conditions has been recently reported, although the identity of the mixed populations involved in perchlorate reduction is not well understood. In order to address this, the bacterial diversity of membrane ...

  10. NOVEL ASSOCIATIONS BETWEEN URINARY PERCHLORATE AND POTENTIALLY RELEVANT EFFECTS ON RISK FACTORS FOR HEART DISEASE BASED ON NHANES 2001-2002

    Science.gov (United States)

    Perchlorate is a widespread environmental pollutant, and is a thyroid hormone disruptor. A previous population study based on the National Health and Nutrition Examination Survey (NHANES) 2001-2002 database showed that urinary perchlorate concentrations were associated with signi...

  11. Adaptive evolution of Desulfovibrio alaskensis G20 for developing resistance to perchlorate

    Science.gov (United States)

    Mehta-Kolte, M. G.; Youngblut, M.; Redford, S.; Gregoire, P.; Carlson, H. K.; Coates, J. D.

    2015-12-01

    Due to its toxic, explosive, and corrosive nature, inadvertent biological H2S production by sulfate reducing microorganisms (SRM) poses significant health and industrial operational risks. Anthropogenic sources are dominated by the oil industry where H2S in reservoir gases and fluids has an associated annual cost estimated at $90 billion globally. Our previous studies have identified perchlorate (ClO4-) as a selective and potent inhibitor of SRM in pure culture and complex microbial ecosystems. However, constant addition of inhibitors like perchlorate to natural ecosystems may result in a new adaptive selective pressure on SRM populations. With this in mind we investigated the ability of Desulfovibrio alaskensis G20, a model oil reservoir SRM, to adapt to perchlorate and develop a resistance. Serial transfers of three parallel cultures with increasing concentrations of perchlorate up to 100 mM were generated and compared to wild-type strains that were transferred for same number of generations in absence of perchlorate. Genome sequencing revealed that all three adapted strains had single non-synonymous single-nucleotide polymorphisms in the same gene, Dde_2265, the sulfate adenylytransferase (ATP sulfurylase (ATPS)) (EC 2.7.7.4). ATPS catalyzes the first committed step in sulfate reduction and is essential in all SRM. IC50s against growth for these evolved strains demonstrated a three-fold increased resistance to perchlorate compared to wild-type controls. These evolved strains also had 5x higher transcriptional abundance of Dde_2265 compared to the wild-type strain. Biochemical characterization of the purified ATPS enzyme from both wild-type and the evolved strain showed that the mutant ATPS from the evolved strain was resistant to perchlorate inhibition of ATP turnover with a KI for perchlorate that was 3x greater relative to the wild-type ATPS. These results demonstrate that a single-base pair mutation in ATPS can have a significant impact on developing

  12. Calcium and bones (image)

    Science.gov (United States)

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  13. Coronary Calcium Scan

    Science.gov (United States)

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  14. Calcium hydroxide poisoning

    Science.gov (United States)

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  15. Calcium source (image)

    Science.gov (United States)

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  16. Calcium in diet

    Science.gov (United States)

    Diet - calcium ... Calcium is one of the most important minerals for the human body. It helps form and maintain healthy teeth and bones. A proper level of calcium in the body over a lifetime can help ...

  17. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  18. Effects of lanthanum nitrate on growth and chlorophyll fluorescence characteristics of Alternanthera philoxeroides under perchlorate stress

    Institute of Scientific and Technical Information of China (English)

    谢寅峰; 蔡贤雷; 刘伟龙; 陶功胜; 陈倩; 张强

    2013-01-01

    To investigate the effects of exogenous lanthanum (La) on Alternanthera philoxeroides (Mart.) Griseb under perchlorate stress, changes in the growth and physiological parameters were investigated in solution culture experiments under controlled condi-tions. Different concentrations of La (NO3)3 were used in our study. It was shown that 0.1 and 0.5 mg/L La3+alleviated the inhibition effect of perchlorate on A. philoxeroides, including relative growth yield, dry weight of different organs, leaf area and root activity. And La3+prevented decline in the relative chlorophyll content and chlorophyll fluorescence parameters including Fv/Fm, Fv'/Fm',ΦPSI and ETR induced by perchlorate stress. Moreover, 0.5 mg/L La3+showed an optimal mitigative effect, while excess La3+(5.0 mg/L) led to synergistic effect on stress. Correlation analysis revealed a significant positive relationship between growth indexes and the chlorophyll fluorescence parameters, root activity and relative chlorophyll content (p<0.05). The results suggested that appropriate concentration of La3+could effectively alleviate growth inhibition and injury of A. philoxeroides caused by perchlorate stress, and the mitigative effect of La3+might be achieved by improving root activity, maintaining chlorophyll content and promoting photochemical efficiency of photosystem II of A. philoxeroides under perchlorate stress.

  19. Perchlorate and Nitrate Remediation Efficiency and Microbial Diversity in a Containerized Wetland Bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Jr., B D; Dibley, V; Pinkart, H; Legler, T

    2004-06-09

    We have developed a method to remove perchlorate (14 to 27 {micro}g/L) and nitrate (48 mg/L) from contaminated groundwater using a wetland bioreactor. The bioreactor has operated continuously in a remote field location for more than two years with a stable ecosystem of indigenous organisms. This study assesses the bioreactor for long-term perchlorate and nitrate remediation by evaluating influent and effluent groundwater for reduction-oxidation conditions and nitrate and perchlorate concentrations. Total community DNA was extracted and purified from 10-g sediment samples retrieved from vertical coring of the bioreactor during winter. Analysis by denaturing gradient gel electrophoresis of short, 16S rDNA, polymerase-chain-reaction products was used to identify dominant microorganisms. Bacteria genera identified were closely affiliated with bacteria widely distributed in soils, mud layers, and fresh water. Of the 17 dominant bands sequenced, most were gram negative and capable of aerobic or anaerobic respiration with nitrate as the terminal electron acceptor (Pseudomonas, Acinetobacter, Halomonas, and Nitrospira). Several identified genera (Rhizobium, Acinetobactor, and Xanthomonas) are capable of fixing atmospheric nitrogen into a combined form (ammonia) usable by host plants. Isolates were identified from the Proteobacteria class, known for the ability to reduce perchlorate. Initial bacterial assessments of sediments confirm the prevalence of facultative anaerobic bacteria capable of reducing perchlorate and nitrate in situ.

  20. Assessment of perchlorate-reducing bacteria in a highly polluted river.

    Science.gov (United States)

    Vigliotta, Giovanni; Motta, Oriana; Guarino, Francesco; Iannece, Patrizia; Proto, Antonio

    2010-11-01

    A 1-year monitoring experiment of the Sarno River basin was conducted during 2008 to evaluate the overall quality of the water over time and to compare the results with those obtained previously. The physico-chemical and microbiological characteristics of the water course had not changed appreciably with respect to previous determinations, thus emphasizing the major contribution of untreated urban wastewater to the overall pollution of the river. Moreover, attention was paid to the perchlorate ion, one of the so-called emerging contaminants, which is widespread in natural environments and is known to have adverse effects on the human thyroid gland. Over the entire monitoring program, we did not find appreciable levels of perchlorate, although the particular environmental condition could support its development. Thus, a dedicated study was designed to assess the presence of bacteria that can reasonably reduce perchlorate levels. By enrichment and molecular procedures, we identified α- and β-Proteobacteria strains, classified by 16S rDNA sequences as Dechlorospirillum sp. and Dechlorosoma sp., respectively. Further physiologic characterization and the presence of the alpha subunit gene (pcrA) of the perchlorate reductase in both strains confirmed the presence in the river of viable and active perchlorate dissimilatory bacteria. PMID:20843743

  1. Surface modification of silver nanofilms for improved perchlorate detection by surface-enhanced Raman scattering.

    Science.gov (United States)

    Hao, Jumin; Han, Mei-Juan; Li, Jinwei; Meng, Xiaoguang

    2012-07-01

    Surface-enhanced Raman scattering (SERS), as one of the most sensitive spectroscopic analysis methods, has been investigated extensively for the detection of environmental contaminants in recent years. In this work, we reported the new development of robust SERS substrates for rapid and sensitive sensing of aqueous perchlorate, a widespread environmental contaminant. The fabrication of the substrates consisted of two simple steps: (a) formation of Ag nanofilms on Cu and surface-roughened Cu foils (Ag/Cu and Ag/rCu nanofilms) using a controllable and inexpensive one-step electroless plating process, and (b) surface modification of the Ag nanofilms with cysteamine (Cys) self-assembly monolayer (SAM) (Cys-Ag/Cu and Cys-Ag/rCu substrates). Due to the strong affinity of -NH(3)(+) groups of the Cys molecules for perchlorate ions, the rapid SERS detection of perchlorate has been realized with a limit of detection (LOD) down to 5 μg L(-1) (ppb) for aqueous samples without need for drying. Various calibration curves with good linear relationships were obtained, indicating the quantification potential of SERS analysis of perchlorate using these new substrates. It was found that the neutral pH yielded the maximum SERS signals, and 85% of original sensitivity was remained in 5 days of storage time in the air, indicating the substrates are fairly stable. Within 10 regeneration-reuse cycles, the SERS signals of perchlorate kept in the range of 85-105% of the original value, verifying its reusability. PMID:22494687

  2. Activation energies involved in isothermal dehydration and decomposition of gamma-irradiated magnesium perchlorate (Paper No. RE-23)

    International Nuclear Information System (INIS)

    Gamma-irradiation enhances the acceleratory rate of dehydration as well as decomposition of magnesium perchlorate. Activation energies computed using Arrhenius treatment decreased with rise in radiation dose prior to its thermal dehydration and decomposition. The reduction in the activation energies may be attributed to the strain and stress produced in voids of the samples of magnesium perchlorate due to irradiation. (author)

  3. Martian Chlorine Chemistry: A Study of Perchlorate on the Martian Surface, Evidence of an Ongoing Formation Mechanism and Implications of a Complex Chlorine Cycle

    Science.gov (United States)

    Carrier, Brandi L.

    2015-10-01

    The research presented herein addresses the detection of perchlorate on Mars, evidence of perchlorate in Mars meteorite EETA 79001, determination of the perchlorate parent salts at the Phoenix landing site, and the ongoing formation of perchlorate from chloride minerals as well as from other oxychlorine species. The detection of perchlorate in three samples by the Phoenix Wet Chemistry Laboratory and the implication of these results are discussed. The further detection of perchlorate in Mars meteorite EETA 79001 by ion chromatography and the determination of the parent salts of the perchlorate detected at the Phoenix landing site by electrochemical analyses and ion chromatography are detailed and the implications of the identity of the parent salts are discussed. The possible formation pathways for martian perchlorate are then explored and a possible mechanism for ongoing perchlorate formation on the martian surface is detailed. Perchlorate is shown to be formed upon exposure of chloride minerals, as well as of chlorite and chlorate salts, to current Mars relevant conditions including temperature, pressure, ultraviolet radiation and atmospheric composition. The implications of this ongoing perchlorate formation for the survival and detection of organics, the oxidizing nature of the soil, formation of liquid brines and recurring slope lineae are discussed. Further preliminary experiments have been conducted to investigate the effects of perchlorate formation on the survival and degradation of organic compounds.

  4. A simplified method for obtaining high-purity perchlorate from groundwater for isotope analyses.

    Energy Technology Data Exchange (ETDEWEB)

    vonKiparski, G; Hillegonds, D

    2011-04-04

    Investigations into the occurrence and origin of perchlorate (ClO{sub 4}{sup -}) found in groundwater from across North America have been sparse until recent years, and there is mounting evidence that natural formation mechanisms are important. New opportunities for identifying groundwater perchlorate and its origin have arisen with the utilization of improved detection methods and sampling techniques. Additionally, application of the forensic potential of isotopic measurements has begun to elucidate sources, potential formation mechanisms and natural attenuation processes. Procedures developed appear to be amenable to enable high precision stable isotopic analyses, as well as lower precision AMS analyses of {sup 36}Cl. Immediate work is in analyzing perchlorate isotope standards and developing full analytical accuracy and uncertainty expectations. Field samples have also been collected, and will be analyzed when final qa/qc samples are deemed acceptable.

  5. The effect of various reaction parameters on bioremediation of perchlorate-contaminated water

    International Nuclear Information System (INIS)

    The bioremediation was employed to treat perchlorate-contaminated water. All enrichments and growth of mixed cultures were performed in anaerobic acetate medium. Enrichment cultures were started with activated sludge obtained from a local wastewater treatment plant where it predominantly treats domestic wastewater. Several parameters affecting perchlorate removal were examined through batch experiments, these include the amount of domesticated sludge, the acetate concentration, pH, the C/N ratio and the reaction temperature. The results indicated that acetate was an effective carbon source and electron donor. Under the selected conditions, namely 1.0 g domesticated sludge, an acetate concentration of 1.2 g l-1, pH 8.0, a C/N ratio of 20 at 40 deg, C, 50 mg l-1 perchlorate could be rapidly reduced to non-detectable levels within 24 h

  6. Dracorhodin perchlorate induces the apoptosis of glioma cells.

    Science.gov (United States)

    Chen, Xin; Luo, Junjie; Meng, Linghu; Pan, Taifeng; Zhao, Binjie; Tang, Zhen-Gang; Dai, Yongjian

    2016-04-01

    Dracorhodin perchlorate (Dp), a synthetic analogue of the antimicrobial anthocyanin red pigment, has recently been shown to induce apoptotic cell death in various types of cancer cells. Yet, the inhibitory effect of Dp on human glioma cells remains uninvestigated. Therefore, in the present study, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were used to detect cell viability and cell cycle progression in glioma U87MG and T98G cells, respectively. Annexin V-FITC/propidium iodide double staining and JC-1 staining were separately applied to determine cellular apoptosis and mitochondrial membrane potential damage in the cells. The expression levels of associated proteins involved in cell cycle progression and apoptosis were measured by western blotting. The activities of caspase‑9/-3 were determined by Caspase-Glo-9/3 assay. The results indicated that Dp treatment significantly inhibited cell proliferation in a dose- and time-dependent manner, and blocked cell cycle progression at the G1/S phase in the U87MG and T98G cells via the upregulation of p53 and p21 protein expression, and simultaneous downregulation of Cdc25A, Cdc2 and P-Cdc2 protein expression. Additionally, Dp treatment led to the loss of cellular mitochondrial membrane potential, and the release of cytochrome c, and strongly induced the occurence of apoptosis. Increased expression levels of Bim and Bax protein and the downregulated expression of Bcl-2 protein were observed. Caspase-9/-3 were activated and their activities were elevated after Dp treatment. These findings indicate that Dp inhibits cell proliferation, induces cell cycle arrest and apoptosis in glioma cells, and is a possible candidate for glioma treatment. PMID:26846469

  7. Microbial perchlorate reduction with elemental sulfur and other inorganic electron donors.

    Science.gov (United States)

    Ju, Xiumin; Sierra-Alvarez, Reyes; Field, Jim A; Byrnes, David J; Bentley, Harold; Bentley, Richard

    2008-03-01

    ClO(4)(-) has recently been recognized as a widespread contaminant of surface and ground water. This research investigated chemolithotrophic perchlorate reduction by bacteria in soils and sludges utilizing inorganic electron-donating substrates such as hydrogen, elemental iron, and elemental sulfur. The bioassays were performed in anaerobic serum bottles with various inocula from anaerobic or aerobic environments. All the tested sludge inocula were capable of reducing perchlorate with H2 as electron donor. Aerobic activated sludge was evaluated further and it supported perchlorate reduction with Fe(0) and S(0) additions under anaerobic conditions. Heat-killed sludge did not convert ClO(4)(-), confirming the reactions were biologically catalyzed. ClO(4)(-) (3mM) was almost completely removed by the first sampling time on d 8 with H2 (> or = 0.37mMd(-1)), after 22d with S(0) (0.18mM d(-1)) and 84% removed after 37d with Fe(0) additions (0.085mMd(-1)). Perchlorate-reduction occurred at a much faster rate (1.12mMd(-1)), when using an enrichment culture developed from the activated sludge with S(0) as an electron donor. The enrichment culture also utilized S(2-) and S(2)O(3)(2-) as electron-donating substrates to support ClO(4)(-) reduction. The mixed cultures also catalyzed the disproportionation of S(0) to S(2-) and SO(4)(2-). Evidence is presented demonstrating that S(0) was directly utilized by microorganisms to support perchlorate-reduction. In all the experiments, ClO(4)(-) was stoichiometrically converted to chloride. The study demonstrates that microorganisms present in wastewater sludges can readily use a variety of inorganic compounds to support perchlorate reduction. PMID:17988714

  8. Effects of larval-juvenile treatment with perchlorate and co-treatment with thyroxine on zebrafish sex ratios

    Science.gov (United States)

    Mukhi, S.; Torres, L.; Patino, R.

    2007-01-01

    The objective of this study was to determine the effect of larval-juvenile exposure to perchlorate, a thyroid hormone synthesis inhibitor, on the establishment of gonadal sex ratios in zebrafish. Zebrafish were exposed to untreated water or water containing perchlorate at 100 or 250 ppm for a period of 30 days starting at 3 days postfertilization (dpf). Recovery treatments consisted of a combination of perchlorate and exogenous thyroxine (T4; 10 nM). Thyroid histology was assessed at the end of the treatment period (33 dpf), and gonadal histology and sex ratios were determined in fish that were allowed an additional 10-day period of growth in untreated water. As expected, exposure to perchlorate caused changes in thyroid histology consistent with hypothyroidism and these effects were reversed by co-treatment with exogenous T4. Perchlorate did not affect fish survival but co-treatment with T4 induced higher mortality. However, relative to the corresponding perchlorate concentration, co-treatment with T4 caused increased mortality only at a perchlorate concentration of 100 ppm. Perchlorate alone or in the presence of T4 suppressed body length at 43 dpf relative to control values. Perchlorate exposure skewed the sex ratio toward female in a concentration-dependent manner, and co-treatment with T4 not only blocked the feminizing effect of perchlorate but also overcompensated by skewing the sex ratio towards male. Moreover, co-treatment with T4 advanced the onset of spermatogenesis in males. There was no clear association between sex ratios and larval survival or growth. We conclude that endogenous thyroid hormone plays a role in the establishment of gonadal sex phenotype during early development in zebrafish. ?? 2006 Elsevier Inc. All rights reserved.

  9. A low cost igniter utilizing an SCB and titanium sub-hydride potassium perchlorate pyrotechnic

    Science.gov (United States)

    Bickes, R. W., Jr.; Grubelich, M. C.; Hartman, J. K.; McCampbell, C. B.; Churchill, J. K.

    1994-01-01

    A conventional NSI (NASA Standard Initiator) normally employs a hot-wire ignition element to ignite ZPP (zirconium potassium perchlorate). With minor modifications to the interior of a header similar to an NSI device to accommodate an SCB (semiconductor bridge), a low cost initiator was obtained. In addition, the ZPP was replaced with THKP (titanium sub-hydride potassium perchlorate) to obtain increased overall gas production and reduced static-charge sensitivity. This paper reports on the all-fire and no-fire levels obtained and on a dual mix device that uses THKP as the igniter mix and a thermite as the output mix.

  10. Linking methane oxidation with perchlorate reduction: a microbial base for possible Martian life

    Science.gov (United States)

    Miller, L. G.; Carlstrom, C.; Baesman, S. M.; Coates, J. D.; Oremland, R. S.

    2011-12-01

    Recent observations of methane (CH4) and perchlorate (ClO4-) within the atmosphere and surface of Mars, respectively, provide impetus for establishing a metabolic linkage between these compounds whereby CH4 acts as an electron donor and perchlorate acts as an electron acceptor. Direct linkage through anaerobic oxidation of methane (AOM) has not been observed. However, indirect syntrophic oxygenase-dependent oxidation of CH4 with an aerobic methane oxidizer is feasible. The pathway for anaerobic dissimilatory perchlorate reduction includes 3 steps. The first 2 are sequential reductions of (1) perchlorate to chlorate and (2) chlorate to chlorite, mediated by perchlorate reductase. The third step is disproportionation of chlorite to chloride and molecular oxygen, mediated by chlorite dismutase. Utilization of thusly derived oxygen by hydrocarbon-degrading organisms in anoxic environments was first demonstrated by Coates et. al. (1998)1, however the link to aerobic methane oxidation was not examined at that time. Here, we systematically explore the potential for several species of aerobic methanotrophs to couple with chlorite during dissimilatory perchlorate reduction. In one experiment, 0.5 kPa CH4 was completely removed in one day from the headspace of combined cell suspensions of Dechloromonas agitata strain CKB and Methylococcus capsulatus in the presence of 5 mM chlorite. Oxidation of labeled 14CH4 to 14CO2 under similar conditions was later confirmed. Another experiment demonstrated complete removal of 0.2 kPa CH4 over several days by Methylobacter albus strain BG8 with strain CKB in the presence of 5 mM chlorite. Finally, we observed complete removal of 0.2 kPa CH4 in bottles containing natural soil (enriched in methanotrophs by CH4 additions over several weeks) and strain CKB and in the presence of 10 mM chlorite. This soil, collected from a pristine lake shoreline, demonstrated endogenous methane, perchlorate, chlorate and chlorite uptake. Other soil and

  11. Calcium and Vitamin D

    Science.gov (United States)

    ... Home › Patients › Treatment › Calcium/Vitamin D Calcium/Vitamin D Getting enough calcium and vitamin D is essential ... counter medications and calcium supplements. What is Vitamin D and What Does it Do? Vitamin D plays ...

  12. Importance of Calcium

    OpenAIRE

    TANDOĞAN, Berivan; ULUSU, N. Nuray

    2005-01-01

    Calcium is the most abundant mineral in the body. Calcium regulates many cellular processes and has important structural roles in living organisms. Skeletal muscle structure and function, polymerisation of fibrin and the conduction of impulses in the nervous system are regulated by calcium. Calcium is an important intracellular messenger in protozoa, plants, and animals. Calcium-transporting systems which are located in the plasma membrane and in the organelles, regulate the ionic concentrati...

  13. High Pressure Burn Rate Measurements on an Ammonium Perchlorate Propellant

    Energy Technology Data Exchange (ETDEWEB)

    Glascoe, E A; Tan, N

    2010-04-21

    High pressure deflagration rate measurements of a unique ammonium perchlorate (AP) based propellant are required to design the base burn motor for a Raytheon weapon system. The results of these deflagration rate measurements will be key in assessing safety and performance of the system. In particular, the system may experience transient pressures on the order of 100's of MPa (10's kPSI). Previous studies on similar AP based materials demonstrate that low pressure (e.g. P < 10 MPa or 1500 PSI) burn rates can be quite different than the elevated pressure deflagration rate measurements (see References and HPP results discussed herein), hence elevated pressure measurements are necessary in order understand the deflagration behavior under relevant conditions. Previous work on explosives have shown that at 100's of MPa some explosives will transition from a laminar burn mechanism to a convective burn mechanism in a process termed deconsolidative burning. The resulting burn rates that are orders-of-magnitude faster than the laminar burn rates. Materials that transition to the deconsolidative-convective burn mechanism at elevated pressures have been shown to be considerably more violent in confined heating experiments (i.e. cook-off scenarios). The mechanisms of propellant and explosive deflagration are extremely complex and include both chemical, and mechanical processes, hence predicting the behavior and rate of a novel material or formulation is difficult if not impossible. In this work, the AP/HTPB based material, TAL-1503 (B-2049), was burned in a constant volume apparatus in argon up to 300 MPa (ca. 44 kPSI). The burn rate and pressure were measured in-situ and used to calculate a pressure dependent burn rate. In general, the material appears to burn in a laminar fashion at these elevated pressures. The experiment was reproduced multiple times and the burn rate law using the best data is B = (0.6 {+-} 0.1) x P{sup (1.05{+-}0.02)} where B is the burn

  14. A steady-state biofilm model for simultaneous reduction of nitrate and perchlorate, part 1: model development and numerical solution.

    Science.gov (United States)

    Tang, Youneng; Zhao, Heping; Marcus, Andrew K; Krajmalnik-Brown, Rosa; Rittmann, Bruce E

    2012-02-01

    A multispecies biofilm model is developed for simultaneous reduction of nitrate and perchlorate in the H(2)-based membrane biofilm reactor. The one-dimension model includes dual-substrate Monod kinetics for a steady-state biofilm with five solid and five dissolved components. The solid components are autotrophic denitrifying bacteria, autotrophic perchlorate-reducing bacteria, heterotrophic bacteria, inert biomass, and extracellular polymeric substances (EPS). The dissolved components are nitrate, perchlorate, hydrogen (H(2)), substrate-utilization-associated products, and biomass-associated products (BAP). The model explicitly considers four mechanisms involved in how three important operating conditions (H(2) pressure, nitrate loading, and perchlorate loading) affect nitrate and perchlorate removals: (1) competition for H(2), (2) promotion of PRB growth due to having two electron acceptors (nitrate and perchlorate), (3) competition between nitrate and perchlorate reduction for the same resources in the PRB: electrons and possibly reductase enzymes, and (4) competition for space in the biofilm. Two other special features are having H(2) delivered from the membrane substratum and solving directly for steady state using a novel three-step approach: finite-difference for approximating partial differential and/or integral equations, Newton-Raphson for solving nonlinear equations, and an iterative scheme to obtain the steady-state biofilm thickness. An example result illustrates the model's features. PMID:22191376

  15. A STUDY ON THE ACCUMULATION OF PERCHLORATE IN YOUNG HEAD LETTUCE

    Science.gov (United States)

    The overall objective of this study was to demonstrate in a greenhouse study the potential for incorporation of perchlorate from aqueous solutions of 10, 50, 100, 500, 1,000, 5,000, and 10,000 ppb into an agricultural food crop (lettuce; Lactuca sativa), which is typically grown ...

  16. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage.

    KAUST Repository

    Balk, Melike

    2010-08-03

    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5-0.8 microm in diameter, and 2-8 microm in length, growing as single cells or in pairs. The cells grew optimally at 37 degrees C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H(2)/CO(2) to acetate, usually as the only product. Succinate was decarboxylated to propionate. The isolate was able to respire with (per)chlorate, nitrate, and CO(2). The G+C content of the DNA was 42.6 mol%. Based on the 16S rRNA gene sequence analysis, strain An4 was most closely related to Sporomusa ovata (98% similarity). The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell-free extracts.

  17. ISSUES IN MANAGING THE RISKS ASSOCIATED WITH PERCHLORATE IN DRINKING WATER

    Science.gov (United States)

    Perchlorate (ClO4-) contamination of ground and surface waters has placed drinking water supplies at risk in communities throughout the US, especially in the West. Several major assessment studies of that risk in terms of health and environmental impact are ...

  18. Trace determination of perchlorate using electromembrane extraction and capillary electrophoresis with capacitively coupled contactless conductivity detection

    Czech Academy of Sciences Publication Activity Database

    Kiplagat, I.K.; Doan, T.K.O.; Kubáň, Pavel; Boček, Petr

    2011-01-01

    Roč. 32, č. 21 (2011), s. 3008-3015. ISSN 0173-0835 R&D Projects: GA ČR GAP206/10/1219 Institutional research plan: CEZ:AV0Z40310501 Keywords : electromembrane extraction * perchlorate * capillary electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.303, year: 2011

  19. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage.

    Science.gov (United States)

    Balk, Melike; Mehboob, Farrakh; van Gelder, Antonie H; Rijpstra, W Irene C; Damsté, Jaap S Sinninghe; Stams, Alfons J M

    2010-09-01

    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5-0.8 microm in diameter, and 2-8 microm in length, growing as single cells or in pairs. The cells grew optimally at 37 degrees C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H(2)/CO(2) to acetate, usually as the only product. Succinate was decarboxylated to propionate. The isolate was able to respire with (per)chlorate, nitrate, and CO(2). The G+C content of the DNA was 42.6 mol%. Based on the 16S rRNA gene sequence analysis, strain An4 was most closely related to Sporomusa ovata (98% similarity). The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell-free extracts. PMID:20680263

  20. Periodate salts as pyrotechnic oxidizers: development of barium- and perchlorate-free incendiary formulations.

    Science.gov (United States)

    Moretti, Jared D; Sabatini, Jesse J; Chen, Gary

    2012-07-01

    In a flash: pyrotechnic incendiary formulations with good stabilities toward various ignition stimuli have been developed without the need for barium or perchlorate oxidizers. KIO(4) and NaIO(4) were introduced as pyrotechnic oxidizers and exhibited excellent pyrotechnic performance. The periodate salts may garner widespread use in military and civilian fireworks because of their low hygroscopicities and high chemical reactivities. PMID:22639415

  1. Developmental exposure to perchlorate alters synaptic transmission in hippocampus of the adult rat.

    Science.gov (United States)

    The Food Quality Protection Act and Safe Drinking Water Act mandate the EPA to identify potential health risks associated with chemicals that act on the endocrine system. Perchlorate, a contaminant found in food and water supplies throughout the USA, blocks iodine uptake into the...

  2. Double-Polymer-Modified Pencil Lead for Stripping Voltammetry of Perchlorate in Drinking Water

    Science.gov (United States)

    Izadyar, Anahita; Kim, Yushin; Ward, Michelle M.; Amemiya, Shigeru

    2012-01-01

    The inexpensive and disposable electrode based on a double-polymer-modified pencil lead is proposed for upper-division undergraduate instrumental laboratories to enable the highly sensitive detection of perchlorate. Students fabricate and utilize their own electrodes in the 3-4 h laboratory session to learn important concepts and methods of…

  3. DISTRIBUTION OF PERCHLORATE IN SAMPLES OF SODIUM NITRATE (CHILE SALTPETER) FERTILIZER DERIVED FROM NATURAL CALICHE

    Science.gov (United States)

    Two lots of sodium nitrate fertilizer derived from Chilean caliche were analyzed to determine the distribution of perchlorate throughout the material. Although our samples represent a limited amount, we found that distribution was essentially homogeneous in any 100-g portion. Whe...

  4. Radioiodine tracers as useful tools in studies of thyrotoxic effects of exogenous bromide and perchlorate ions

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    2012-01-01

    Roč. 291, č. 2 (2012), s. 405-408. ISSN 0236-5731 R&D Projects: GA ČR(CZ) GA304/08/0256 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * perchlorate * radioiodine tracer * thyroid hormone Subject RIV: ED - Physiology Impact factor: 1.467, year: 2012

  5. Preparation and Analysis of Solid Solutions in the Potassium Perchlorate-Permanganate System.

    Science.gov (United States)

    Johnson, Garrett K.

    1979-01-01

    Describes an experiment, designed for and tested in an advanced inorganic laboratory methods course for college seniors and graduate students, that prepares and analyzes several samples in the nearly ideal potassium perchlorate-permanganate solid solution series. The results are accounted for by a theoretical treatment based upon aqueous…

  6. 高氯酸诺氟沙星铜(Ⅱ)%Norfloxacin Coppe(Ⅱ) Perchlorate

    Institute of Scientific and Technical Information of China (English)

    谢永荣; 叶琼; 熊仁根

    2004-01-01

    The hydrothermal treatment of Cu(ClO4)2·6H2O and Norfloxacin (H-Norf) afforded [Cu(H-Noff)2(ClO4)2] (1) in which center Cu has a square planar geometry while perchlorate just acts as charge balance anions. CCDC:140821.

  7. Radiation decomposition of ammonium perchlorate in the presence of composite rocket propellant ingredients

    International Nuclear Information System (INIS)

    Radiolysed ammonium perchlorate (AP) oxidises aqueous iodide ions more when it is irradiated in combination with either aluminium, hydroxy terminated polybutadiene (HTPB), copper chromite or iron oxide. The influence is large in the case of AP + HTPB and AP + Copper chromite. (author)

  8. Fractionation of stable isotopes in perchlorate and nitrate during in situ biodegradation in a sandy aquifer

    Science.gov (United States)

    Hatzinger, P.B.; Böhlke, J.K.; Sturchio, N.C.; Gu, B.; Heraty, L.J.; Borden, R.C.

    2009-01-01

    Environmental context. Perchlorate (ClO4-) and nitrate (NO3-) are common co-contaminants in groundwater, with both natural and anthropogenic sources. Each of these compounds is biodegradable, so in situ enhanced bioremediation is one alternative for treating them in groundwater. Because bacteria typically fractionate isotopes during biodegradation, stable isotope analysis is increasingly used to distinguish this process from transport or mixing-related decreases in contaminant concentrations. However, for this technique to be useful in the field to monitor bioremediation progress, isotope fractionation must be quantified under relevant environmental conditions. In the present study, we quantify the apparent in situ fractionation effects for stable isotopes in ClO4- (Cl and O) and NO3- (N and O) resulting from biodegradation in an aquifer. Abstract. An in situ experiment was performed in a shallow alluvial aquifer in Maryland to quantify the fractionation of stable isotopes in perchlorate (Cl and O) and nitrate (N and O) during biodegradation. An emulsified soybean oil substrate that was previously injected into this aquifer provided the electron donor necessary for biological perchlorate reduction and denitrification. During the field experiment, groundwater extracted from an upgradient well was pumped into an injection well located within the in situ oil barrier, and then groundwater samples were withdrawn for the next 30 h. After correction for dilution (using Br- as a conservative tracer of the injectate), perchlorate concentrations decreased by 78% and nitrate concentrations decreased by 82% during the initial 8.6 h after the injection. The observed ratio of fractionation effects of O and Cl isotopes in perchlorate (18O/37Cl) was 2.6, which is similar to that observed in the laboratory using pure cultures (2.5). Denitrification by indigenous bacteria fractionated O and N isotopes in nitrate at a ratio of ???0.8 (18O/15N), which is within the range of values

  9. Systematics of Natural Perchlorate in Precipitation, Soils, and Plants at the Amargosa Desert Research Site, Nye County, Nevada

    Science.gov (United States)

    Andraski, B. J.; Stonestrom, D. A.; Jackson, W. A.; Rajagopalan, S.; Taylor, E. M.

    2007-12-01

    Naturally occurring perchlorate is known to be associated with nitrate deposits of the hyperarid Atacama Desert in Chile, and recent large-scale sampling has identified a substantial reservoir (up to 1 kg/ha) of natural perchlorate in diverse unsaturated zones of the arid and semiarid Southwestern United States (Rao et al., 2007, ES&T, DOI: 10.1021/es062853i). The objective of the Amargosa Desert work is to develop a better understanding of the deposition, accumulation, and biological cycling of perchlorate in arid environments. Occurrence of perchlorate was evaluated by sampling shallow soil profiles up to 3 m in depth at four different locations and at two different time periods, and by sampling dominant plant species growing near the subsurface profiles. Deposition of perchlorate was evaluated by analyzing both bulk deposition (precipitation plus dry fall, collected under oil) collected on site and wet deposition samples collected by the National Atmospheric Deposition program at a nearby site. Soil samples and atmospheric-deposition samples were tested for both perchlorate (ClO4- ) and major anions. Perchlorate concentrations (0.2-20 µg/kg) were variable with depth in soil profiles and generally correlated most highly with chloride (Cl-) and nitrate (NO3-), although the intensity of these relations differed among profiles. Plant concentrations were generally above 1 mg/kg, suggesting ClO4- accumulation. Concentrations of ClO4- were generally much greater in total deposition than wet deposition samples, indicating a substantial dryfall component of meteoric deposition. This presentation will present the mass distribution and variability of perchlorate in bulk deposition, soils, and plants. Reasons for observed relations between subsurface concentrations of perchlorate and other anions will be explored.

  10. The determination of calcium in phosphate, carbonate, and silicate rocks by flame photometer

    Science.gov (United States)

    Kramer, Henry

    1956-01-01

    A method has been developed for the determination of calcium in phosphate, carbonate, and silicate rocks using the Beckman flame photometer, with photomultiplier attachement. The sample is dissolved in hydrofluoric, nitric, and perchloric acids, the hydrofluoric and nitric acids are expelled, a radiation buffer consisting of aluminum, magnesium, iron, sodium, potassium, phosphoric acid, and nitric acid is added, and the solution is atomized in an oxy-hydrogen flame with an instrument setting of 554 mµ. Measurements are made by comparison against calcium standards, prepared in the same manner, in the 0 to 50 ppm range. The suppression of calcium emission by aluminum and phosphate was overcome by the addition of a large excess of magnesium. This addition almost completely restores the standard curve obtained from a solution of calcium nitrate. Interference was noted when the iron concentration in the aspirated solution (including the iron from the buffer) exceeded 100 ppm iron. Other common rock-forming elements did not interfere. The results obtained by this procedure are within ± 2 percent of the calcium oxide values obtained by other methods in the range 1 to 95 percent calcium oxide. In the 0 to 1 percent calcium oxide range the method compares favorably with standard methods.

  11. Calcium in diet

    Science.gov (United States)

    ... best source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain a form of calcium ... the amount of calcium in a dairy product. Yogurt, most cheeses, and buttermilk are excellent sources of ...

  12. Fenoprofen calcium overdose

    Science.gov (United States)

    Fenoprofen calcium is a type of medicine called a nonsteroidal anti-inflammatory drug. It is a prescription pain medicine used to relieve symptoms of arthritis . Fenoprofen calcium overdose occurs when someone takes more than the ...

  13. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  14. Fenoprofen calcium overdose

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  15. Dissimilatory perchlorate reduction linked to aerobic methane oxidation via chlorite dismutase

    Science.gov (United States)

    Oremland, R. S.; Baesman, S. M.; Miller, L. G.

    2013-12-01

    The presence of methane (CH4) in the atmosphere of Mars is controversial yet the evidence has aroused scientific interest, as CH4 could be a harbinger of extant or extinct microbial life. There are various oxidized compounds present on the surface of Mars that could serve as electron acceptors for the anaerobic oxidation of CH4, including perchlorate (ClO4-). We examined the role of perchlorate, chlorate (ClO3-) and chlorite (ClO2-) as oxidants linked to CH4 oxidation. Dissimilatory perchlorate reduction begins with reduction of ClO4- to ClO2- and ends with dismutation of chlorite to yield chloride (Cl-) and molecular oxygen (O2). We explored the potential for aerobic CH4 oxidizing bacteria to couple with oxygen derived from chlorite dismutation during dissimilatory perchlorate reduction. Methane (0.2 kPa) was completely removed within several days from the N2-flushed headspace above cell suspensions of methanotrophs (Methylobacter albus strain BG8) and perchlorate reducing bacteria (Dechloromonas agitata strain CKB) in the presence of 5 mM ClO2-. Similar rates of CH4 consumption were observed for these mixed cultures whether they were co-mingled or segregated under a common headspace, indicating that direct contact of cells was not required for methane consumption to occur. We also observed complete removal of 0.2 kPa CH4 in bottles containing dried soil (enriched in methanotrophs by CH4 additions over several weeks) and D. agitata CKB and in the presence of 10 mM ClO2-. This soil (seasonally exposed sediment) collected from the shoreline of a freshwater lake (Searsville Lake, CA) demonstrated endogenous CH4 uptake as well as perchlorate, chlorate and chlorite reduction/dismutation. However, these experiments required physical separation of soil from the aqueous bacterial culture to allow for the partitioning of O2 liberated from chlorite dismutation into the shared headspace. Although dissimilatory reduction of ClO4- and ClO3- could be inferred from the

  16. Calcium and magnesium disorders.

    Science.gov (United States)

    Goff, Jesse P

    2014-07-01

    Hypocalcemia is a clinical disorder that can be life threatening to the cow (milk fever) and predisposes the animal to various other metabolic and infectious disorders. Calcium homeostasis is mediated primarily by parathyroid hormone, which stimulates bone calcium resorption and renal calcium reabsorption. Parathyroid hormone stimulates the production of 1,25-dihydroxyvitamin D to enhance diet calcium absorption. High dietary cation-anion difference interferes with tissue sensitivity to parathyroid hormone. Hypomagnesemia reduces tissue response to parathyroid hormone. PMID:24980727

  17. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  18. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.

    1985-01-01

    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of cardiop

  19. Physiological and genetic description of dissimilatory perchlorate reduction by the novel marine bacterium Arcobacter sp. strain CAB.

    Science.gov (United States)

    Carlström, Charlotte I; Wang, Ouwei; Melnyk, Ryan A; Bauer, Stefan; Lee, Joyce; Engelbrektson, Anna; Coates, John D

    2013-01-01

    A novel dissimilatory perchlorate-reducing bacterium (DPRB), Arcobacter sp. strain CAB, was isolated from a marina in Berkeley, CA. Phylogenetically, this halophile was most closely related to Arcobacter defluvii strain SW30-2 and Arcobacter ellisii. With acetate as the electron donor, strain CAB completely reduced perchlorate (ClO4(-)) or chlorate (ClO3(-)) [collectively designated (per)chlorate] to innocuous chloride (Cl(-)), likely using the perchlorate reductase (Pcr) and chlorite dismutase (Cld) enzymes. When grown with perchlorate, optimum growth was observed at 25 to 30°C, pH 7, and 3% NaCl. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) preparations were dominated by free-swimming straight rods with 1 to 2 polar flagella per cell. Strain CAB utilized a variety of organic acids, fructose, and hydrogen as electron donors coupled to (per)chlorate reduction. Further, under anoxic growth conditions strain CAB utilized the biogenic oxygen produced as a result of chlorite dismutation to oxidize catechol via the meta-cleavage pathway of aerobic catechol degradation and the catechol 2,3-dioxygenase enzyme. In addition to (per)chlorate, oxygen and nitrate were alternatively used as electron acceptors. The 3.48-Mb draft genome encoded a distinct perchlorate reduction island (PRI) containing several transposases. The genome lacks the pcrC gene, which was previously thought to be essential for (per)chlorate reduction, and appears to use an unrelated Arcobacter c-type cytochrome to perform the same function. IMPORTANCE The study of dissimilatory perchlorate-reducing bacteria (DPRB) has largely focused on freshwater, mesophilic, neutral-pH environments. This study identifies a novel marine DPRB in the genus Arcobacter that represents the first description of a DPRB associated with the Campylobacteraceae. Strain CAB is currently the only epsilonproteobacterial DPRB in pure culture. The genome of strain CAB lacks the pcrC gene found in all

  20. Determination of perchlorate in drinking water by ion chromatography using macrocycle-based concentration and separation methods.

    Science.gov (United States)

    Lamb, John D; Simpson, David; Jensen, Bryce D; Gardner, Joseph S; Peterson, Quinn P

    2006-06-16

    Macrocycle-based ion chromatography provides a convenient, reliable method for the determination of perchlorate ion, which is currently of great interest to the environmental community. This study shows that effective perchlorate determinations can be made using standard conductimetric detection by combining an 18-crown-6-based mobile phase with an underivatized reversed-phase mobile phase ion chromatography (MPIC) column. One unique feature of this method is the flexibility in column capacity that is achieved through simple variations in eluent concentrations of 18-crown-6 and KOH, facilitating the separation of target analyte anions such as perchlorate. Using a standard anion exchange column as concentrator makes possible the determination of perchlorate as low as 0.2 ug/L in low ionic strength matrices. Determination of perchlorate at the sub-ug/L level in pure water and in spiked local city hard water samples with high background ion concentrations can be achieved this way. However, like other IC techniques, this method is challenged to achieve analyses at the ug/L level in the demanding high ionic strength matrix described by the United States Environmental Protection Agency (EPA) (1,000 mg/L chloride, sulfate and carbonate). We approached this challenge by use of the Cryptand C1 concentrator column, provided by Dionex Corporation, to effectively preconcentrate perchlorate while reducing background ion concentrations in the high ionic strength matrix. The retention characteristics of the concentrator column were studied in order to maximize its effectiveness for perchlorate determinations. The method makes possible the determination of perchlorate at the 5 ug/L level in the highest ionic strength matrix described by the EPA. PMID:16516902

  1. Perchlorate content of plant foliage reflects a wide range of species-dependent accumulation but not ozone-induced biosynthesis

    International Nuclear Information System (INIS)

    Perchlorate (ClO4−) interferes with uptake of iodide in humans. Emission inventories do not explain observed distributions. Ozone (O3) is implicated in the natural origin of ClO4−, and has increased since pre-industrial times. O3 produces ClO4−in vitro from Cl−, and plant tissues contain Cl− and redox reactions. We hypothesize that O3 exposure may induce plant synthesis of ClO4−. We exposed contrasting crop species to environmentally relevant O3 concentrations. In the absence of O3 exposure, species exhibited a large range of ClO4− accumulation but there was no relationship between leaf ClO4− and O3, whether expressed as exposure or cumulative flux (dose). Older, senescing leaves accumulated more ClO4− than younger leaves. O3 exposed vegetation is not a source of environmental ClO4−. There was evidence of enhanced ClO4− content in the soil surface at the highest O3 exposure, which could be a significant contributor to environmental ClO4−. -- Highlights: • Exposure to ozone in crop species does not induce accumulation nor biosynthesis of perchlorate. • Older leaves accumulate more perchlorate than younger leaves. • Soil surface may accumulate perchlorate following exposure to ozone. • Species differ greatly in accumulation of perchlorate from the rhizosphere, independent of ozone. • Ozone exposed vegetation is not a candidate source of environmental perchlorate. -- Exposure of crop species to ozone did not lead to biosynthesis or greater accumulation of foliar perchlorate. Older leaves accumulated more perchlorate than younger leaves

  2. Oxygen and chlorine isotopic fractionation during perchlorate biodegradation: Laboratory results and implications for forensics and natural attenuation studies

    Science.gov (United States)

    Sturchio, N.C.; Böhlke, J.K.; Beloso, A.D., Jr.; Streger, S.H.; Heraty, L.J.; Hatzinger, P.B.

    2007-01-01

    Perchlorate is a widespread environmental contaminant having both anthropogenic and natural sources. Stable isotope ratios of O and Cl in a given sample of perchlorate may be used to distinguish its source(s). Isotopic ratios may also be useful for identifying the extent of biodegradation of perchlorate, which is critical for assessing natural attenuation of this contaminant in groundwater. For this approach to be useful, however, the kinetic isotopic fractionations of O and Cl during perchlorate biodegradation must first be determined as a function of environmental variables such as temperature and bacterial species. A laboratory study was performed in which the O and Cl isotope ratios of perchlorate were monitored as a function of degradation by two separate bacterial strains (Azospira suillum JPLRND and Dechlorospirillum sp. FBR2) at both 10??C and 22??C with acetate as the electron donor. Perchlorate was completely reduced by both strains within 280 h at 22??C and 615 h at 10??C. Measured values of isotopic fractionation factors were ??18O = -36.6 to -29.0??? and ??37Cl = -14.5 to -11.5???, and these showed no apparent systematic variation with either temperature or bacterial strain. An experiment using 18O-enriched water (??18O = +198???) gave results indistinguishable from those observed in the isotopically normal water (??18O = -8.1???) used in the other experiments, indicating negligible isotope exchange between perchlorate and water during biodegradation. The fractionation factor ratio ??18O/??37Cl was nearly invariant in all experiments at 2.50 ?? 0.04. These data indicate that isotope ratio analysis will be useful for documenting perchlorate biodegradation in soils and groundwater. The establishment of a microbial fractionation factor ratio (??18O/??37Cl) also has significant implications for forensic studies. ?? 2007 American Chemical Society.

  3. A Reservoir of Natural Perchlorate in Unsaturated Zones of Arid and Semi-Arid Regions, Southwestern USA

    Science.gov (United States)

    Rao, B. A.; Stonestrom, D. A.; Anderson, T. A.; Orris, G. J.; Rajagapolan, S.; Sandvig, R. M.; Scanlon, B. R.; Walvoord, M. A.; Jackson, W.

    2006-12-01

    Natural perchlorate (ClO4-) is generally present in unsaturated zones of steppe-to-desert regions of the arid and semi-arid southwestern United States. The perchlorate is associated with atmospherically deposited chloride that has accumulated throughout the Holocene. To assess this natural reservoir, we analyzed unsaturated-zone profiles from ten sites across Nevada, New Mexico, Texas, and Utah for perchlorate and other anions. The sampled sites represent a wide range of precipitation (0.1 0.5 m yr-1), dominant vegetation, soil type, underlying geology, and include five distinct ecological regions: Chihuahuan, Mojave, and southern Great Basin deserts; Arizona-New Mexico semi-desert; and Texas High Plains dry steppe. Concentrations of perchlorate correlated closely with chloride and bromide. The perchlorate reservoir (up to 1 kg ha-1) is sufficiently large to impact groundwater when natural recharge during pluvial periods or induced recharge after conversion to agriculture flushes accumulated salts from the unsaturated zone. This little explored source can explain perchlorate in milk and other agricultural products far from anthropogenic contamination, and should be considered when evaluating overall exposure risk.

  4. Secondary transformation mechanism of paramagnetic centers in irradiated alkali metal perchlorates

    International Nuclear Information System (INIS)

    The EPR method has been used to study thermal transformations of paramagnetic centres (PC) in X-ray irradiated potassium, rubidium and cesium perchlorates. Experimental data make it possible to suppose that diffusion coefficient of O- ion a rather high and this ion is freely diffused already at 262 K. Colliding with [MeClO4]+ centres it is transformed in a molecule of oxygen. Another part of O- is transformed in stable ozonide-ion at 300 K. About room temperature hole centres dissociate with formation of ClO2 radical. It is supposed that part of electron and hole centres is not stabilized but at 77 K it is transformed in stable radiolysis products. This process most effective proceeds in dislocations and on the surface of microcrystals. The suggested model of thermal transformations of primary PC in irradiated perchlorates of alkali metals explains formation of all the finite ion and paramagnetic radiolysis products

  5. Kinetics of oxidation of uranium(IV) by permanganate ion in aqueous perchlorate media

    International Nuclear Information System (INIS)

    The kinetics of oxidation of uranium(IV) by permanganate ion in 1.0 mol dm-3 perchloric acid solution has been investigated using a stopped-flow spectrophotometer. The reaction was found to be second order overall and first order in the concentrations of both reactants. The catalytic effect of the perchlorates of Hg2+, Cu2+, and Fe3+ on the reaction rate has been investigated. The activation parameters were evaluated and found to be ΔS not= 30.52 ± 1.22 kJ-1 mol-1, ΔH not= 62.89 ± 1.87 kJ mol-1, and ΔG not=53.79 ± 1.44 kJ mol-1. A tentative mechanism consistent with the kinetics is discussed. (author)

  6. Laboratory investigation of perchlorate deliquescence at the surface of Mars with a Raman scattering lidar

    Science.gov (United States)

    Nikolakakos, George; Whiteway, James A.

    2015-10-01

    A sample of magnesium perchlorate hexahydrate was subjected to the water vapor pressure and temperatures found at the landing site of the Phoenix Mars mission. Laser Raman scattering was applied to detect the onset of deliquescence and provide a relative estimate of the quantity of water taken up and subsequently released by the sample. As the temperature of the sample decreased at the same rate as measured on Mars during the evening, significant uptake of water from the atmosphere was observed to occur prior to the frost point temperature being reached. As the temperature was lowered further, the relative humidity over ice increased to 100% and frost formed on the surface surrounding the perchlorate sample. Freezing of the brine film was observed at the eutectic temperature of -67°C, and thawing occurred at a temperature of -62°C.

  7. trans-Tetraaquabis[bis(pyridin-3-ylmethanone-κN]manganese(II bis(perchlorate

    Directory of Open Access Journals (Sweden)

    Bin Liu

    2012-01-01

    Full Text Available In the title complex, [Mn(C11H8N2O2(H2O4](ClO42, the Mn2+ ion is located on an inversion center with the slightly distorted N2O4 octahedral coordination sphere comprising N-atom donors from two monodentate trans-related bis(pyridin-3-ylmethanone ligands and four water ligands. The two perchlorate anions are linked to the mononuclear complex molecule through water O—H...O hydrogen bonds while inter-complex water O—H...N(pyridine interactions form an infinite chain structure extending along the b axis. The perchlorate anions also function as inter-unit links through water O—H...O hydrogen bonds which, together with water O—H...O(carbonyl interactions, give a three-dimensional framework structure.

  8. Thermal behavior of aluminum powder and potassium perchlorate mixtures by DTA and TG

    International Nuclear Information System (INIS)

    In this work the thermal decomposition characteristics of micron sized aluminum powder + potassium perchlorate pyrotechnic systems were studied with thermal analytical techniques. The results show that the reactivity of aluminum powder in air increases as the particle size decreases. Pure aluminum with 5 μm particle size has a fusion temperature about 647 deg. C, but this temperature for 18 μm powder is 660 deg. C. Pure potassium perchlorate has an endothermic peak at 300 deg. C corresponding to a rhombic-cubic transition, a fusion temperature around 590 deg. C and decomposes at 592 deg. C. DTA curves for Al5/KClO4 (30:70) mixture show a maximum peak temperature for thermal decomposition at 400 deg. C. Increasing the particle size of aluminum powder increases the ignition temperature of the mixture. The oxidation temperature increased by enhance in the aluminum content of the mixture

  9. Thermal behavior of aluminum powder and potassium perchlorate mixtures by DTA and TG

    Energy Technology Data Exchange (ETDEWEB)

    Pourmortazavi, S.M. [Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of)]. E-mail: pourmortazavi@yahoo.com; Fathollahi, M. [Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of); Hajimirsadeghi, S.S. [Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of); Hosseini, S.G. [Faculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of)

    2006-04-01

    In this work the thermal decomposition characteristics of micron sized aluminum powder + potassium perchlorate pyrotechnic systems were studied with thermal analytical techniques. The results show that the reactivity of aluminum powder in air increases as the particle size decreases. Pure aluminum with 5 {mu}m particle size has a fusion temperature about 647 deg. C, but this temperature for 18 {mu}m powder is 660 deg. C. Pure potassium perchlorate has an endothermic peak at 300 deg. C corresponding to a rhombic-cubic transition, a fusion temperature around 590 deg. C and decomposes at 592 deg. C. DTA curves for Al{sub 5}/KClO{sub 4} (30:70) mixture show a maximum peak temperature for thermal decomposition at 400 deg. C. Increasing the particle size of aluminum powder increases the ignition temperature of the mixture. The oxidation temperature increased by enhance in the aluminum content of the mixture.

  10. Radiation-chemical behaviour of Rh(3) in perchloric and nitric acid media

    International Nuclear Information System (INIS)

    Rhodium(3) behaviour in solutions of concentrated (> 1 mol/l) nitric and perchloric acids under 60Co gamma radiation with dose rate of 3.5 Gy/s has been studied. It is shown that in case of nitrate solution irradiation by doses up to 2x104 Gy, rhodium(3) concentration does not change. Rhodium(3) proved to be stable in perchlorate solutions in case of irradiation by doses up to 3x104 Gy; however, in the presence of organic acids and alcohols its reduction to methane occurred. Kinetic characteristics of rhodium(3) reduction by ethyl alcohol by the doses up to 4x104 Gy have been ascertained, reduction mechanism being considered. 6 refs.; 4 figs.; 1 tab

  11. Experimental investigation on the heterogeneous kinetic process of the low thermal decomposition of ammonium perchlorate particles

    Energy Technology Data Exchange (ETDEWEB)

    Longuet, Baptiste [Laboratoire Energetique Explosions et Structures Universite d' Orleans (Germany); Gillard, Philippe [Laboratoire Energetic Explosions et Structures, Universite d' Orleans, Bourges (France)

    2009-02-15

    The thermal decomposition of ammonium perchlorate has been extensively studied in the past. Nevertheless, the various results published illustrate, on the one hand, significant differences regarding the influence of different parameters on the decomposition and on the other hand, a lack of useful quantitative laws to predict the thermal behaviour of this crystal under a range of conditions (temperature, duration of exposure, presence of confinement). (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  12. Non-aqueous titrimetric assay of gabapentin in capsules using perchloric acid as titrant

    OpenAIRE

    Sameer A. M. Abdulrahman; KANAKAPURA BASAVAIAH

    2011-01-01

    Two simple, rapid, accurate and inexpensive methods using visual and potentiometric titrimetric techniques are described for the determination of gabapentin (GBP) in bulk drug as well as in capsules. The methods are based on the neutralization reaction of the primary amino group of GBP with acetous perchloric acid as titrant in anhydrous acetic acid medium. The end point was detected either visually using crystal violet as indicator or potentiometrically using a modified glass electrode SCE e...

  13. Electrochromic iridium oxide films: Compatibility with propionic acid, potassium hydroxide, and lithium perchlorate in propylene carbonate

    OpenAIRE

    Wen, Rui-Tao; Niklasson, Gunnar A.; Granqvist, Claes G.

    2013-01-01

    Porous thin films of It oxide were prepared by reactive dc magnetron sputtering onto unheated substrates. The crystallite size was similar to 5 nm, and a small amount of unoxidized Ir was present. The electrochromic performance was studied by optical transmittance measurements and cyclic voltammetry applied to films in aqueous and non-aqueous electrolytes, specifically being 1 M propionic acid, 1 M potassium hydroxide (KOH), and 1 M lithium perchlorate in propylene carbonate (Li-PC). Cyclic v...

  14. Disproportionation of plutonium IV in concentrated solutions of plutonium in perchloric acid

    International Nuclear Information System (INIS)

    This work was carried out to study the dependence of the PuIV disproportionation reaction in perchloric acid solution on the plutonium concentration up to 20 g/l. Solutions of such high plutonium concentration have not previously been studied. It was found that the bimolecular rate constant and the equilibrium constant of the disproportionation reaction were not appreciably different from their values at lower concentrations. (author)

  15. Radiometric quantification of thyrotoxic and goitrogenic effects of exogenous bromide and perchlorate ions

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Bratislava: Slovenská technická univerzita, 2012, s. 152-156. ISBN 978-80-227-3722-7. [Priemyselná toxikológia 2012 /32./. Svit, Vysoké Tatry (SK), 20.06.2012-22.06.2012] R&D Projects: GA ČR(CZ) GA304/08/0256 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * perchlorate * radiometric assay * thyroid peroxidase Subject RIV: ED - Physiology

  16. The use of chlorate, nitrate, and perchlorate to promote crude oil mineralization in salt marsh sediments.

    Science.gov (United States)

    Brundrett, Maeghan; Horita, Juske; Anderson, Todd; Pardue, John; Reible, Danny; Jackson, W Andrew

    2015-10-01

    Due to the high volume of crude oil released by the Deepwater Horizon oil spill, the salt marshes along the gulf coast were contaminated with crude oil. Biodegradation of crude oil in salt marshes is primarily limited by oxygen availability due to the high organic carbon content of the soil, high flux rate of S(2-), and saturated conditions. Chlorate, nitrate, and perchlorate were evaluated for use as electron acceptors in comparison to oxygen by comparing oil transformation and mineralization in mesocosms consisting of oiled salt marsh sediment from an area impacted by the BP Horizon oil spill. Mineralization rates were determined by measuring CO2 production and δ (13)C of the produced CO2 and compared to transformation evaluated by measuring the alkane/hopane ratios over a 4-month period. Total alkane/hopane ratios decreased (~55-70 %) for all treatments in the following relative order: aerated ≈ chlorate > nitrate > perchlorate. Total CO2 produced was similar between treatments ranging from 550-700 mg CO2-C. The δ (13)C-CO2 values generally ranged between the indigenous carbon and oil values (-17 and -27‰, respectively). Oil mineralization was greatest for the aerated treatments and least for the perchlorate amended. Our results indicate that chlorate has a similar potential as oxygen to support oil mineralization in contaminated salt marshes, but nitrate and perchlorate were less effective. The use of chlorate as a means to promote oil mineralization in situ may be a promising means to remediate contaminated salt marshes while preventing unwanted secondary impacts related to nutrient management as in the case of nitrate amendments. PMID:25854211

  17. The Investigation of Perchlorate/Iron Phase Mixtures as A Possible Source of Oxygen Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

    Science.gov (United States)

    Sutter, B.; Heil, E.; Morris, R. V.; Archer, P. D.; Ming, D. W.; Niles, P. B.; Eigenbrode, J. L.; Franz, H.; Freissinet C.; Glavin, D. P.; McAdam, A. C.; Mahaffy, P.; Martin-Torres, F. Javier; Navarro-Gonzalez, R.; Paz-Zorzano, Maria; Stern, J. C.; McKay, C. P.

    2015-01-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detected O2 and HCl gas releases from the Rocknest (RN) eolian bedform and the John Klein (JK) and Cumberland (CB) drill hole materials in Gale Crater. Chlorinated hydrocarbons have also been detected by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS). These detections along with the detection of perchlorate (ClO4-) by the Mars Phoenix Lander's Wet Chemistry Laboratory (WCL) suggesting perchlorate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of individual per-chlorates has yet to provide an unequivocal temperature match to the SAM O2 and HCl release data. These detections along with the detection of perchlorate (ClO4-) by the Mars Phoenix Lander's Wet Chemistry Laboratory suggested perchlorate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of pure perchlorates has yet to provide an unequivocal temperature match to the SAM O2 and HCl release data. Analog laboratory analysis of iron mineralogy detected in Gale materials that was physically mixed with Ca- and Mg-perchlorate has been shown to catalyze lower O2 release temperatures and approach some SAM O2 release data. Instead of physical mixtures used in previous work, the work presented here utilized perchlorate solutions added to Fe phases. This technique allowed for perchlorate to come in closer contact with the Fe-phase and may more closely mimic Mars conditions where humidity can increase enough to cause deliquescence of the highly hygroscopic perchlorate phases. The objective of this work is to: 1) Utilize a laboratory SAM analog instrument to evaluate the O2 release temperatures from Mg- and Ca-perchlorates solutions applied to Fephases detetected in Gale Crate; and 2) Determine if perchlorate solutions can provide improved matches with the SAM O2 temperature release profiles.

  18. Evaluation of the natural attenuation potential of a complex pollution plume (chlorate, perchlorate, 1,2dichloroethane and vinyl chloride) by autochthonous microbial communities

    OpenAIRE

    Harris-Hellal, Jennifer; Joulian, Catherine; Hube, Daniel; Coulon, Stéphanie; Guérin, Valérie; Garrido, Françis

    2013-01-01

    Artificially synthetized chloride-based-oxyanions such as perchlorate (ClO4-) and chlorate (ClO3-), are used in a vast number of applications such as military and aerospace industry; they are also used as herbicides and in pyrotechnic applications. Due to their very high solubility, perchlorate and chlorate are readily transported in water systems and can thus end up in drinking water. Ingestion of perchlorate may affect iodine uptake by the human thyroid and thus thyroidal hormone production...

  19. Kinetics of thermal decomposition of nano magnesium oxide catalyzed ammonium perchlorate

    International Nuclear Information System (INIS)

    Arrhenius kinetic parameters of ammonium perchlorate (AP) catalyzed with nano-sized magnesium oxide (MgO) has been determined in this work. Nano particles of MgO with an average size of approximately 20 to 30 nm have been used to catalyze the AP. The particles were characterized using Scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques before mixing with AP. Simultaneous Thermal Analysis (STA) shows that MgO nanoparticles have a strong catalytic effect on the thermal decomposition of ammonium perchlorate. The addition of MgO nano particles reduces the two stage decomposition of ammonium perchlorate to a single stage. Arrhenius kinetic parameters of pure and the catalyzed AP have been calculated using non isothermal kinetic approach based on Kissinger method. The comparison of the thermal behavior and kinetic parameters of pure and catalyzed AP has also been carried out to elucidate the reaction mechanism. The results show that the activation energy of the catalyzed AP has increased from 138.1 kJ/mole to 159.1kJ/mole. The rate of reaction, however, has increased in the catalyzed AP showing that it has become more reactive by the addition of MgO nano particles. The enthalpy of activation has increased by 16 percent in the catalyzed AP. (author)

  20. Temporal and spatial variation of perchlorate in streambed sediments: results from in-situ dialysis samplers

    International Nuclear Information System (INIS)

    The fate of perchlorate (ClO4-) in streambed sediments is becoming a concern due to the increasing number of groundwater and surface water contamination sites in the United States. Dialysis samplers were deployed at three sites over a period of 1 year to determine the vertical distribution of ClO4-in sediment pore water. Results indicated that the spatial and temporal ClO4-penetration into sediments could be affected by numerous factors, such as temperature, microbial degradation, ClO4-surface water concentration, and sediment physico-geological properties. In general, maximum ClO4-penetration into sediments at the studied sites was 30 cm below the sediment-water surface. The vertical sequential depletion of electron acceptors in sediments suggested that microbial reduction was responsible for ClO4-depletion in stream sediments. Biodegradation of ClO4-occurred over a seasonally variable active depth zone of 1-10 cm. Results implied that there was a rapid natural attenuation potential of perchlorate in saturated near-surface sediments. -Perchlorate may be rapidly attenuated in saturated near-surface sediments

  1. Widespread occurrence of perchlorate in water, foodstuffs and human urine collected from Kuwait and its contribution to human exposure.

    Science.gov (United States)

    Alomirah, Husam F; Al-Zenki, Sameer F; Alaswad, Marivi C; Alruwaih, Noor A; Wu, Qian; Kannan, Kurunthachalam

    2016-06-01

    Perchlorate is a thyroid hormone-disrupting compound and is reported to occur widely in the environment. Little is known on human exposure to perchlorate in Kuwait. In this study, 218 water samples, 618 commonly consumed foodstuffs and 532 urine samples collected from Kuwait were analysed to assess the exposure of the Kuwaiti population to perchlorate. For the estimation of daily intake of perchlorate, food consumption rates were obtained from the National Nutrition Survey in the State of Kuwait (NNSSK). The results showed that leafy vegetables accounted for a major share of perchlorate exposure among the Kuwaiti population at 0.062 µg kg(-)(1) bw day(-)(1) (36.2%), followed by fruits at 0.026 µg kg(-)(1) bw day(-)(1) (15.3%) and non-leafy vegetables at 0.017 µg kg(-)(1) bw day(-)(1) (10.1%). The urinary perchlorate geometric mean (GM) concentrations ranged from 8.51 to 17.1 µg l(-)(1) for the five age groups, which were higher than those reported in other countries. The estimated urinary perchlorate exposure for the Kuwaiti general population was 0.42 µg kg(-)(1) bw day(-)(1), which was higher than that reported for the United States. The dietary intake of perchlorate for the Kuwaiti population ranged from 0.14 to 0.67 µg kg(-)(1) bw day(-)(1) for the five age groups, with a mean total daily intake of 0.17 µg kg(-)(1) bw day(-)(1) for the general population. The highest estimated dietary mean daily intake of perchlorate (0.67 µg kg(-)(1) bw day(-)(1)) was found for children at 3-5 years. The estimated dietary perchlorate exposure in Kuwait is higher than the recommended mean reference dose (RfD) but lower than that of provisional maximum tolerable daily intake (PMTDI) set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). PMID:27248576

  2. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  3. EXERCISE ENHANCING CALCIUM ABSORPTION MECHANISM

    OpenAIRE

    Muliani

    2013-01-01

    Calcium has important role in many biological processes therefore calcium homeostasis should be maintained. Imbalance in calcium homeostasis would affects the bone metabolism, neuromuscular function, blood coagulation, cell proliferation and signal transduction. Homeostasis of calcium is maintained by three major organs: gastrointestinal tract, bone and kidney. Intestinal calcium absorption is the sole mechanism to supply calcium to the body. Calcium absorption controlled by calcitropic hormo...

  4. Inhibition of microbial sulfate reduction in a flow-through column system by (per)chlorate treatment.

    Science.gov (United States)

    Engelbrektson, Anna; Hubbard, Christopher G; Tom, Lauren M; Boussina, Aaron; Jin, Yong T; Wong, Hayden; Piceno, Yvette M; Carlson, Hans K; Conrad, Mark E; Anderson, Gary; Coates, John D

    2014-01-01

    Microbial sulfate reduction is a primary cause of oil reservoir souring. Here we show that amendment with chlorate or perchlorate [collectively (per)chlorate] potentially resolves this issue. Triplicate packed columns inoculated with marine sediment were flushed with coastal water amended with yeast extract and one of nitrate, chlorate, or perchlorate. Results showed that although sulfide production was dramatically reduced by all treatments, effluent sulfide was observed in the nitrate (10 mM) treatment after an initial inhibition period. In contrast, no effluent sulfide was observed with (per)chlorate (10 mM). Microbial community analyses indicated temporal community shifts and phylogenetic clustering by treatment. Nitrate addition stimulated Xanthomonadaceae and Rhizobiaceae growth, supporting their role in nitrate metabolism. (Per)chlorate showed distinct effects on microbial community structure compared with nitrate and resulted in a general suppression of the community relative to the untreated control combined with a significant decrease in sulfate reducing species abundance indicating specific toxicity. Furthermore, chlorate stimulated Pseudomonadaceae and Pseudoalteromonadaceae, members of which are known chlorate respirers, suggesting that chlorate may also control sulfidogenesis by biocompetitive exclusion of sulfate-reduction. Perchlorate addition stimulated Desulfobulbaceae and Desulfomonadaceae, which contain sulfide oxidizing and elemental sulfur-reducing species respectively, suggesting that effluent sulfide concentrations may be controlled through sulfur redox cycling in addition to toxicity and biocompetitive exclusion. Sulfur isotope analyses further support sulfur cycling in the columns, even when sulfide is not detected. This study indicates that (per)chlorate show great promise as inhibitors of sulfidogenesis in natural communities and provides insight into which organisms and respiratory processes are involved. PMID:25071731

  5. Dengue and Calcium

    OpenAIRE

    Shivanthan, Mitrakrishnan C; Rajapakse, Senaka

    2014-01-01

    Dengue is potentially fatal unless managed appropriately. No specific treatment is available and the mainstay of treatment is fluid management with careful monitoring, organ support, and correction of metabolic derangement. Evidence with regards to the role of calcium homeostasis in dengue is limited. Low blood calcium levels have been demonstrated in dengue infection and hypocalcemia maybe more pronounced in more severe forms. The cause of hypocalcemia is likely to be multifactorial. Calcium...

  6. Measurements of intracellular calcium

    International Nuclear Information System (INIS)

    Intracellular calcium concentration ([Ca2+]i) has been measured in cultured cells by using Fura-2 load cells and a computer-controlled Perkin Elmer LS-5B spectrofluorometer. Increased [Ca2+]i in cells exposed to extracellular bilirubin was observed both with and without extracellular calcium. However, the increase was considerable larger with extracellular calcium. The enhancement of [Ca2+]i became smaller with decreasing bilirubin/BSA (bovine serum albumine) ratio. 5 refs., 5 figs

  7. Rapid measurement of perchlorate in polar ice cores down to sub-ng L(-1) levels without pre-concentration.

    Science.gov (United States)

    Peterson, Kari; Cole-Dai, Jihong; Brandis, Derek; Cox, Thomas; Splett, Scott

    2015-10-01

    An ion chromatography-electrospray ionization-tandem mass spectrometry (IC-ESI-MS/MS) method has been developed for rapid and accurate measurement of perchlorate in polar snow and ice core samples in which perchlorate concentrations are expected to be as low as 0.1 ng L(-1). Separation of perchlorate from major inorganic species in snow is achieved with an ion chromatography system interfaced to an AB SCIEX triple quadrupole mass spectrometer operating in multiple reaction monitoring mode. Under optimized conditions, the limit of detection and lower limit of quantification without pre-concentration have been determined to be 0.1 and 0.3 ng L(-1), respectively, with a linear dynamic range of 0.3-10.0 ng L(-1) in routine measurement. These represent improvements over previously reported methods using similar analytical techniques. The improved method allows fast, accurate, and reproducible perchlorate quantification down to the sub-ng L(-1) level and will facilitate perchlorate measurement in the study of natural perchlorate production with polar ice cores in which perchlorate concentrations are anticipated to vary in the low and sub-ng L(-1) range. Initial measurements of perchlorate in ice core samples from central Greenland show that typical perchlorate concentrations in snow dated prior to the Industrial Revolution are about 0.8 ng L(-1), while perchlorate concentrations are significantly higher in recent (post-1980) snow, suggesting that anthropogenic sources are a significant contributor to perchlorate in the current environment. PMID:26297465

  8. (Per)chlorate reduction by the thermophilic bacterium Moorella perchloratireducens sp. nov., isolated from underground gas storage.

    Science.gov (United States)

    Balk, Melike; van Gelder, Ton; Weelink, Sander A; Stams, Alfons J M

    2008-01-01

    A thermophilic bacterium, strain An10, was isolated from underground gas storage with methanol as a substrate and perchlorate as an electron acceptor. Cells were gram-positive straight rods, 0.4 to 0.6 mum in diameter and 2 to 8 mum in length, growing as single cells or in pairs. Spores were terminal with a bulged sporangium. The temperature range for growth was 40 to 70 degrees C, with an optimum at 55 to 60 degrees C. The pH optimum was around 7. The salinity range for growth was between 0 and 40 g NaCl liter(-1) with an optimum at 10 g liter(-1). Strain An10 was able to grow on CO, methanol, pyruvate, glucose, fructose, cellobiose, mannose, xylose, and pectin. The isolate was able to respire with (per)chlorate, nitrate, thiosulfate, neutralized Fe(III) complexes, and anthraquinone-2,6-disulfonate. The G+C content of the DNA was 57.6 mol%. On the basis of 16S rRNA analysis, strain An10 was most closely related to Moorella thermoacetica and Moorella thermoautotrophica. The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell extracts. Strain An10 is the first thermophilic and gram-positive bacterium with the ability to use (per)chlorate as a terminal electron acceptor. PMID:17981952

  9. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  10. Serum Calcium Level in Hypertension

    OpenAIRE

    Hazari, Mohammed Abdul Hannan; Arifuddin, Mehnaaz Sameera; Muzzakar, Syed; Reddy, Vontela Devender

    2012-01-01

    Background: The alterations in extracellular calcium level may influence intracellular calcium level and possibly play a role in the pathogenesis of essential hypertension. Aim: The purpose was to find out the association between serum calcium levels and hypertension; and to compare the serum calcium levels between normotensive controls, hypertensive subjects on calcium channel blockers, and hypertensive subjects on antihypertensive medication other than calcium channel blockers. Materials an...

  11. Light and variable 37Cl/35Cl ratios in rocks from Gale Crater, Mars: Possible signature of perchlorate

    Science.gov (United States)

    Farley, K. A.; Martin, P.; Archer, P. D.; Atreya, S. K.; Conrad, P. G.; Eigenbrode, J. L.; Fairén, A. G.; Franz, H. B.; Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; Malespin, C.; Ming, D. W.; Navarro-Gonzalez, R.; Sutter, B.

    2016-03-01

    Cl isotope ratios measured on HCl thermally evolved from as-yet-unknown phases in sedimentary rocks and sand in Gale Crater provide unexpected insights to the Martian surficial Cl cycle. The seven samples yield δ37Cl values ranging from - 1 ± 25 ‰ to - 51 ± 5 ‰. Five analyses from two samples of the Sheepbed mudstone (Yellowknife Bay study area) are analytically indistinguishable with a mean δ37Cl of - 11 ± 7 ‰ (1 σ). In contrast, four mudstones/sandstones from the Kimberley and Pahrump study areas also yielded indistinguishable ratios, but with a mean δ37Cl of - 43 ± 6 ‰. The Rocknest sand deposit gave a highly uncertain δ37Cl value of - 7 ± 44 ‰. These light and highly variable δ37Cl values are unique among known solar system materials. Two endmember models are offered to account for these observations, and in both, perchlorate, with its extreme ability to fractionate Cl isotopes, is critical. In the first model, SAM is detecting HCl from an oxychlorine compound (e.g., perchlorate) produced from volcanic gas emissions by atmospheric chemical reactions. Similar reactions in Earth's atmosphere may be responsible for the isotopically lightest known Cl outside of this study, in perchlorate from the Atacama Desert. Some of the Gale Crater δ37Cl values are more negative than those in Atacama perchlorate, but because reaction mechanisms and associated fractionation factors are unknown, it is impossible to assess whether this difference is prohibitive. If the negative δ37Cl signal is produced in this fashion, the isotopic variability among samples could arise either from variations in the relative size of the reactant chloride and product perchlorate reservoirs, or from variations in the fraction of perchlorate reduced back to chloride after deposition. Such reduction strongly enriches 37Cl in the residual perchlorate. Perchlorate reduction alone offers an alternative endmember model that can explain the observed data if SAM measured HCl derived

  12. Electron donors and co-contaminants affect microbial community composition and activity in perchlorate degradation.

    Science.gov (United States)

    Guan, Xiangyu; Xie, Yuxuan; Wang, Jinfeng; Wang, Jing; Liu, Fei

    2015-04-01

    Although microbial reduction of perchlorate (ClO4(-)) is a promising and effective method, our knowledge on the changes in microbial communities during ClO4(-) degradation is limited, especially when different electron donors are supplied and/or other contaminants are present. Here, we examined the effects of acetate and hydrogen as electron donors and nitrate and ammonium as co-contaminants on ClO4(-) degradation by anaerobic microcosms using six treatments. The process of degradation was divided into the lag stage (SI) and the accelerated stage (SII). Quantitative PCR was used to quantify four genes: pcrA (encoding perchlorate reductase), cld (encoding chlorite dismutase), nirS (encoding copper and cytochrome cd1 nitrite reductase), and 16S rRNA. While the degradation of ClO4(-) with acetate, nitrate, and ammonia system (PNA) was the fastest with the highest abundance of the four genes, it was the slowest in the autotrophic system (HYP). The pcrA gene accumulated in SI and played a key role in initiating the accelerated degradation of ClO4(-) when its abundance reached a peak. Degradation in SII was primarily maintained by the cld gene. Acetate inhibited the growth of perchlorate-reducing bacteria (PRB), but its effect was weakened by nitrate (NO3(-)), which promoted the growth of PRB in SI, and therefore, accelerated the ClO4(-) degradation rate. In addition, ammonia (NH4(+)), as nitrogen sources, accelerated the growth of PRB. The bacterial communities' structure and diversity were significantly affected by electron donors and co-contaminants. Under heterotrophic conditions, both ammonia and nitrate promoted Azospira as the most dominant genera, a fact that might significantly influence the rate of ClO4(-) natural attenuation by degradation. PMID:25382499

  13. The Effects of Perchlorates on the Permafrost Methanogens: Implication for Autotrophic Life on Mars

    Directory of Open Access Journals (Sweden)

    Viktoria Shcherbakova

    2015-09-01

    Full Text Available The terrestrial permafrost represents a range of possible cryogenic extraterrestrial ecosystems on Earth-like planets without obvious surface ice, such as Mars. The autotrophic and chemolithotrophic psychrotolerant methanogens are more likely than aerobes to function as a model for life forms that may exist in frozen subsurface environments on Mars, which has no free oxygen, inaccessible organic matter, and extremely low amounts of unfrozen water. Our research on the genesis of methane, its content and distribution in permafrost horizons of different ages and origin demonstrated the presence of methane in permanently frozen fine-grained sediments. Earlier, we isolated and described four strains of methanogenic archaea of Methanobacterium and Methanosarcina genera from samples of Pliocene and Holocene permafrost from Eastern Siberia. In this paper we study the effect of sodium and magnesium perchlorates on growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. In this paper we study the effect of sodium and magnesium perchlorates on the growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. Furthermore, as shown in the studies strain M2T M. arcticum, probably can use perchlorate anion as an electron acceptor in anaerobic methane oxidation. Earth’s subzero subsurface environments are the best approximation of environments on Mars, which is most likely to harbor methanogens; thus, a biochemical understanding of these pathways is expected to provide a basis for designing experiments to detect autotrophic methane-producing life forms on Mars.

  14. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free calciu

  15. Development of Biosensors for Real Time Analysis of Perchlorate in Water

    OpenAIRE

    Frankenberger, William T.; Okeke, Benedict C.; Cheng, Quan Jason

    2006-01-01

    Perchlorate (ClO4 -) contamination of ground water is a widespread problem in the U.S., which can adversely affect human health and wildlife. Current methods for detecting and quantifying ClO4 - in water are time consuming, expensive, and subject to error due to complex procedures and various interferences. Thus, there is an urgent need to develop a method that can accurately detect and measure low concentrations of ClO4 - in the field. This study reports the construction of a ClO4 -- reducta...

  16. Bis(1,10-phenanthroline)lithium perchlorate: crystal structure and dissociation of complex in acetone

    International Nuclear Information System (INIS)

    Composition of solid phase formed in acetone at concentration ratios of 1,10-phenanthroline (phen) and LiClO4 near 2:1 is established. Molecular structure of bis(1,10-phenanthroline)lithium perchlorate is determined by X-ray structural analysis: space group Pnna, a=7.191(2), b=39.929(9), c=14.494(3) A, Z=8, Dx=1.490 g/cm3. Data of IR spectroscopy in acetone denotes dissociation of the Li(phen)2ClO4 complex for the 1:1 composition complex and molecule phen in the solution equilibrium with the solid phase

  17. Lanthanide perchlorate complexes of quinoline-1-oxide and isoquinoline-2-oxide

    OpenAIRE

    Kalyanasundaram, R; Navaneetham, NS; Soundararajan, S.

    1985-01-01

    Complexes of lanthanide perchlorates with quinoline-1-oxide and isoquinoline-2-oxide have been isolated for the first time characterised by analysis, conductance and IR, NMR and electronic spectoral studies. The complexes of quinoline-1-oxide have the composition $Ln(QNO)_8$$(ClO_4)_3$ where Ln = La, Pr or Nd and $Ln(QNO)_7$ where Ln = Gd, Dy, Ho, Er, Yb. The isoquinoline-2-oxide complexes analyse for the formula $Ln(IsoQNO)_7(ClO_4)_3$ where Ln = La-Yb.

  18. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage

    OpenAIRE

    2010-01-01

    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5–0.8 μm in diameter, and 2–8 μm in length, growing as single cells or in pairs. The cells grew optimally at 37°C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H2/CO2 to acetate, usually as the only product. ...

  19. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage

    OpenAIRE

    Balk, M.; Mehboob, F.; Gelder, van, M.; Rijpstra, I.; Sinninghe-Damsté, J.S.; Stams, A.J.M.

    2010-01-01

    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5-0.8 microm in diameter, and 2-8 microm in length, growing as single cells or in pairs. The cells grew optimally at 37 degrees C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H(2)/CO(2) to acetate, usually a...

  20. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage

    OpenAIRE

    Balk, M.; Mehboob, F.; van Gelder, T; Rijpstra, W.I.C.; J. S. Sinninghe Damsté; Stams, A.J.M.

    2010-01-01

    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5–0.8 μm in diameter, and 2–8 μm in length, growing as single cells or in pairs. The cells grew optimally at 37°C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H2/CO2 to acetate, usually as the only product. ...

  1. 2-(2-Hydroxy-3-methoxyphenyl-1H-benzimidazol-3-ium perchlorate

    Directory of Open Access Journals (Sweden)

    Chuan Chen

    2012-06-01

    Full Text Available In the title molecular salt, C14H13N2O2+·ClO4−, the ring systems in the cation are almost coplanar [dihedral angle = 5.53 (13°]. Intramolecular N—H...O and O—H...O hydrogen bonds generate S(6 and S(5 rings, respectively. In the crystal, the two H atoms involved in the intramolecular hydrogen bonds also participate in intermolecular links to acceptor O atoms of the perchlorate anions. A simple intermolecular N—H...O bond also occurs. Together, these form a double-chain structure along [101].

  2. Combined effects of perchlorate, thiocyanate, and iodine on thyroid function in the National Health and Nutrition Examination Survey 2007–08

    Energy Technology Data Exchange (ETDEWEB)

    Steinmaus, Craig, E-mail: craigs@berkeley.edu [Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, 1515 Clay St. 16th Floor, Oakland, CA 94612 (United States); Miller, Mark D., E-mail: ucsfpehsumiller@gmail.com [Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, 1515 Clay St. 16th Floor, Oakland, CA 94612 (United States); Cushing, Lara, E-mail: lara.cushing@berkeley.edu [Energy and Resources Group, 310 Barrows Hall, University of California, Berkeley, CA 93720-3050 (United States); Blount, Benjamin C., E-mail: bkb3@cdc.gov [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, NE, Mail Stop F47, Atlanta, GA (United States); Smith, Allan H., E-mail: ahsmith@berkeley.edu [Arsenic Health Effects Research Group, 1950 Addison St., Suite 204, University of California, Berkeley, CA 94704 (United States)

    2013-05-15

    Perchlorate, thiocyanate, and low iodine intake can all decrease iodide intake into the thyroid gland. This can reduce thyroid hormone production since iodide is a key component of thyroid hormone. Previous research has suggested that each of these factors alone may decrease thyroid hormone levels, but effect sizes are small. We hypothesized that people who have all three factors at the same time have substantially lower thyroid hormone levels than people who do not, and the effect of this combined exposure is substantially larger than the effects seen in analyses focused on only one factor at a time. Using data from the 2007–2008 National Health and Nutrition Examination Survey, subjects were categorized into exposure groups based on their urinary perchlorate, iodine, and thiocyanate concentrations, and mean serum thyroxine concentrations were compared between groups. Subjects with high perchlorate (n=1939) had thyroxine concentrations that were 5.0% lower (mean difference=0.40 μg/dl, 95% confidence interval=0.14–0.65) than subjects with low perchlorate (n=2084). The individual effects of iodine and thiocyanate were even smaller. Subjects with high perchlorate, high thiocyanate, and low iodine combined (n=62) had thyroxine concentrations 12.9% lower (mean difference=1.07 μg/dl, 95% confidence interval=0.55–1.59) than subjects with low perchlorate, low thiocyanate, and adequate iodine (n=376). Potential confounders had little impact on results. Overall, these results suggest that concomitant exposure to perchlorate, thiocyanate, and low iodine markedly reduces thyroxine production. This highlights the potential importance of examining the combined effects of multiple agents when evaluating the toxicity of thyroid-disrupting agents. -- Highlights: ► Recent data suggest that essentially everyone in the US is exposed to perchlorate. ► Perchlorate exposure may be associated with lower thyroid hormone levels. ► Some groups may be more susceptible to

  3. Combined effects of perchlorate, thiocyanate, and iodine on thyroid function in the National Health and Nutrition Examination Survey 2007–08

    International Nuclear Information System (INIS)

    Perchlorate, thiocyanate, and low iodine intake can all decrease iodide intake into the thyroid gland. This can reduce thyroid hormone production since iodide is a key component of thyroid hormone. Previous research has suggested that each of these factors alone may decrease thyroid hormone levels, but effect sizes are small. We hypothesized that people who have all three factors at the same time have substantially lower thyroid hormone levels than people who do not, and the effect of this combined exposure is substantially larger than the effects seen in analyses focused on only one factor at a time. Using data from the 2007–2008 National Health and Nutrition Examination Survey, subjects were categorized into exposure groups based on their urinary perchlorate, iodine, and thiocyanate concentrations, and mean serum thyroxine concentrations were compared between groups. Subjects with high perchlorate (n=1939) had thyroxine concentrations that were 5.0% lower (mean difference=0.40 μg/dl, 95% confidence interval=0.14–0.65) than subjects with low perchlorate (n=2084). The individual effects of iodine and thiocyanate were even smaller. Subjects with high perchlorate, high thiocyanate, and low iodine combined (n=62) had thyroxine concentrations 12.9% lower (mean difference=1.07 μg/dl, 95% confidence interval=0.55–1.59) than subjects with low perchlorate, low thiocyanate, and adequate iodine (n=376). Potential confounders had little impact on results. Overall, these results suggest that concomitant exposure to perchlorate, thiocyanate, and low iodine markedly reduces thyroxine production. This highlights the potential importance of examining the combined effects of multiple agents when evaluating the toxicity of thyroid-disrupting agents. -- Highlights: ► Recent data suggest that essentially everyone in the US is exposed to perchlorate. ► Perchlorate exposure may be associated with lower thyroid hormone levels. ► Some groups may be more susceptible to

  4. Neuronal calcium sparks and intracellular calcium “noise”

    OpenAIRE

    Melamed-Book, Naomi; Kachalsky, Sylvia G.; Kaiserman, Igor; Rahamimoff, Rami

    1999-01-01

    Intracellular calcium ions are involved in many forms of cellular function. To accommodate so many control functions, a complex spatiotemporal organization of calcium signaling has developed. In both excitable and nonexcitable cells, calcium signaling was found to fluctuate. Sudden localized increases in the intracellular calcium concentration—or calcium sparks—were found in heart, striated and smooth muscle, Xenopus Laevis oocytes, and HeLa and P12 cells. In the nervous system, intracellular...

  5. Extraction-spectrophotometric determination of niobium with 1,2,4,6-tetraphenylpyridinium perchlorate and thiocyanate

    International Nuclear Information System (INIS)

    1,2,4,6-Tetraphenylpyridinium (TPP+) as the acetate or perchlorate was used as a counter ion in the spectrophotometric determination of Nb(V) by extraction into toluene of the anionic Nb(V) -thiocyanate complex from 4 to 6 M hydrochloric acid. The molar absorptivity of the ion-association complex, whose composition was shown to be NbOCl(SCN)3-.TPP+, was 2.82 x 104 l mol-1cm-1 at 395 nm. Beer's law was obeyed over the range 0.1 to 2.5 μg ml-1 of Nb(V). The method was applied to the determination of niobium in standard steels and ores with good precision and accuracy. 1-(4'-Nitrophenyl)-2,4,6-triphenylpyridinium (nitro-TPP+) perchlorate was also synthesised and used in the spectrophotometric determination of Nb(V), but did not show advantages over TPP+. The fluorescence of TPP+ and Nb(V)-SCN--TPP+ solutions in toluene also disappeared when nitro-TPP+ was used, owing to the paramagnetic effect of the NO2 group. (author)

  6. Interfacial behavior of perchlorate versus chloride ions in saturated aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosal, S; Kuo, I W; Baer, M D; Bluhm, H

    2009-04-14

    In recent years combination of theoretical and experimental work have presented a novel view of the aqueous interface wherein hard and/or multiply charged ions are excluded from the interface, but large polarizable anions show interfacial enhancement relative to the bulk. The observed trend in the propensity of anions to adsorb at the air/water interface appears to be reverse of the Hofmeister series for anions. This study focuses on experimental and theoretical examination of the partitioning behavior of perchlorate (ClO{sub 4}{sup -}) and chloride (Cl{sup -}) ions at the air/water interface. We have used ambient pressure X-ray photoelectron spectroscopy technique to directly probe the interfacial concentrations of ClO{sub 4}{sup -} and Cl{sup -} ions in sodium perchlorate and sodium chloride solutions, respectively. Experimental observations are compared with first principles molecular dynamics simulations. Both experimental and simulation results show enhancement of ClO{sub 4}{sup -} ion at the interface, compared with the absence of such enhancement in the case of Cl{sup -} ion. These observations are in agreement with the expected trend in the interfacial propensity of anions based on the Hofmeister series.

  7. 123Iodine scintigraphy and perchlorate discharge test in the diagnosis of congenital hypothyroidism

    International Nuclear Information System (INIS)

    Aim: Thirty eight children suffering from congenital primary permanent hypothyroidism were studied to determine the diagnostic impact of 123I scintigraphy in comparison to laboratory findings and ultrasonography. Methods: In all patients 123I scintigraphy was performed after intravenous administration of 3,7 MBq 123I. If accumulation of the radiotracer in thyroid tissue occured a perchlorate discharge test was performed subsequently. Results: Scintigraphy revealed athyrosis in 7 children. In 9 children a lingual thyroid was observed. Deficiency in iodine organification was diagnosed by a significant discharge of 123I in 15 patients. In four of these children the diagnosis of Pendred's syndrome could be established. Ectopic thyroid tissue could be demonstrated only by scintigraphy where clinical examination and sonography failed in the diagnosis in all cases. Hypoplasia of the thyroid gland as it was diagnosed in 2 cases by ultrasonography appeared to be unlikely because of normal 123I uptake was seen in these patients. In 2 patients with scintigraphic proven athyrosis an orthotopic gland had been falsely considered by ultrasound. In 44% of our patients the final diagnosis could only be established if 123I scintigraphy and perchlorate discharge test were performed. Conclusion: This findings suggest that scintigraphy is indispensible in the correct diagnostic work up of congenital hypothyroidism. (orig.)

  8. Sol-gel preparation of a di-ureasil electrolyte doped with lithium perchlorate

    International Nuclear Information System (INIS)

    Solid polymer electrolytes (SPEs) synthesized by the sol-gel process and designated as di-ureasils have been prepared through the incorporation of lithium perchlorate, LiClO4, into the d-U(2000) organic-inorganic hybrid network. Electrolytes with lithium salt compositions of n (where n indicates the number of oxyethylene units per Li+ ion) between ∞ and 0.5 were characterized by conductivity measurements, cyclic voltammetry at a gold microelectrode, thermal analysis and Fourier transform Raman (FT-Raman) spectroscopy. The conductivity results obtained suggest that this system offers a quite significant improvement over previously characterized analogues doped with lithium triflate [S.C. Nunes, V. de Zea Bermudez, D. Ostrovskii, M.M. Silva, S. Barros, M.J. Smith, R.A. Sa Ferreira, L.D. Carlos, J. Rocha, E. Morales, J. Electrochem. Soc. 152 (2) (2005), A429]. 'Free' perchlorate ions, detected in all the samples examined, are identified as the main charge carriers in the sample that yields the highest room temperature conductivity (n = 20). In the di-ureasils with n ≤ 10 ionic association is favoured and the ionic conductivity drops

  9. Nano-Ammonium Perchlorate: Preparation, Characterization, and Evaluation in Composite Propellant Formulation

    Science.gov (United States)

    Kumari, A.; Mehilal; Jain, S.; Jain, M. K.; Bhattacharya, B.

    2013-07-01

    Nanomaterials are finding applications in explosives and propellant formulations due to their large surface area and high surface energy. This high surface energy is responsible for the low activation energy and increase in burning rate of the composition. Therefore, a successful attempt has been made to prepare nano-ammonium perchlorate using a nonaqueous method by dissolving ammonium perchlorate (AP) in methanol followed by adding the dissolved AP to the hydroxyl-terminated polybutadiene (HTPB), homogenization, and vacuum distillation of the solvent. The nano-AP thus formed was characterized using a NANOPHOX particle size analyzer (Sympatec, Germany), transmission electron microscopy (FEI, Hillsboro, OR), X-ray diffraction (PANalytical B.V., The Netherlands) and scanning electron microscopy (Ikon Analytical Equipment Pvt. Ltd., Mumbai, India) for particle size, purity, and morphology, respectively. The thermal behavior of nano-AP was also studied using differential thermal analysis-thermo gravimetric analysis (DTA-TGA). The data indicated that the particle size of the prepared AP was in the range of 21-52 nm and the thermal decomposition temperature was lower than that of coarse AP. Characterized nano-AP was subsequently used in composite propellant formulation up to 5% with 86% solid loading and studied for different properties. The results showed a 14% increase in burning rate in comparison to standard propellant composition with desired mechanical properties.

  10. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk;

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...... calcium binds silicon primarily as calcium silicates and less as potassium calcium silicates....

  11. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  12. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    NARCIS (Netherlands)

    Jonge, H.J. de; Gans, R.O.; Huls, G.A.

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate ab

  13. Reversible, Selective Trapping of Perchlorate from Water in Record Capacity by a Cationic Metal-Organic Framework.

    Science.gov (United States)

    Colinas, Ian R; Silva, Rachel C; Oliver, Scott R J

    2016-02-16

    We report the capture of ppm-level aqueous perchlorate in record capacity and kinetics via the complete anion exchange of a cationic metal-organic framework. Ambient conditions were used for both the synthesis of silver 4,4'-bipyridine nitrate (SBN) and the exchange, forming silver 4,4'-bipyridine perchlorate (SBP). The exchange was complete within 90 min, and the capacity was 354 mg/g, representing 99% removal. These values are greater than current anion exchangers such as the resins Amberlite IRA-400 (249 mg/g), Purolite A530E (104 mg/g), and layered double hydroxides (28 mg/g). Moreover, unlike resins and layered double hydroxides, SBN is fully reusable and displays 96% regeneration to SBN in nitrate solution, with new crystal formation allowing the indefinite cycling for perchlorate. We show seven cycles as proof of concept. Perchlorate contamination of water represents a serious health threat because it is a thyroid endocrine disruptor. This noncomplexing anionic pollutant is significantly mobile and environmentally persistent. Removal of other anionic pollutants from water such as chromate, pertechnetate, or arsenate may be possible by this methodology. PMID:26765213

  14. Anomalous aryl strengthening of americium and europium complexes during extraction by alkylenediphosphine dioxides from perchloric acid media

    International Nuclear Information System (INIS)

    Extraction of americium and europium from perchlorate environments by solutions of three types of methylenediphosphine dioxides, namely (C6H5)P(O)(CH2)sub(n)(O)P(C6H5)2, (C6H5)2P(O)CH2(O)P(C8H17)2 and (C8H17)2P(O)(CH2)sub(n)(O)P(C8H17)2 has been studied (n is 1 or 2 ) The diluents used have been dichlorethane and chloroform. In perchlorate environments the distribuiton coefficients of americium and europium have proved to be by about 3 orders of magnitude higher than in nitric acid environments, i.e. in perchlorate media the complexes are far more stable. Separation coefficients of americium and REE in perchloric acid soutions are much higher than in nitrate environments. The average value of Am/Eu separation coeffecient at 1-5 M acidity was about 6 (with dichlorethane as diluent) or about 7 (with chloroform as diluent). The complexes essentially exist as trisolvated. Americium complexes display anomalous stability increase upon being diluted: by about 2 orders of magnitude with dichlorethane and by up to 3 orders of magnitude with chloroform used as diluent

  15. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  16. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    Science.gov (United States)

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

    The gravimetric determination of calcium as calcium carbonate is described. This experiment is suitable for undergraduate quantitative analysis laboratories. It is less expensive than determination of chloride as silver chloride. (BB)

  17. Effect of Triethanolamine and Benzaldehyde on the Storage Stability of Polystyrene- Ammonium Perchlorate Propellant

    Directory of Open Access Journals (Sweden)

    K. Kishore

    1986-10-01

    Full Text Available The effect of triethanolamine and benzaldehyde on the stability of polystyrene has been studied by dynamic thermogravimetry (TG. Slower decomposition of polymer in the presence of these compounds indicates their inhibiting ability on the oxidation of the polymer. The burning rate measurements of polystyrene (PS/ammonium perchlorate (AP propellants at ambient temperature and pressure shows an increase with the storage time. The percentage change in the burning rate of the propellants containing aldehyde and amine is less during the ageing which indicates the increased stability of the propellants. The safe-life time of the propellants for the ballistic stability has been calculated from the activation energy for the ageing process using an Arrhenius type equation. The safe-life of the propellants containing triethanolamine and benzaldehyde is more than the neat propellant.

  18. Potentiometric Electronic Tongue to Resolve Mixtures of Sulfide and Perchlorate Anions

    Directory of Open Access Journals (Sweden)

    Deivy Wilson

    2011-03-01

    Full Text Available This work describes the use of an array of potentiometric sensors and an artificial neural network response model to determine perchlorate and sulfide ions in polluted waters, by what is known as an electronic tongue. Sensors used have been all-solid-state PVC membrane selective electrodes, where their ionophores were different metal-phtalocyanine complexes with specific and anion generic responses. The study case illustrates the potential use of electronic tongues in the quantification of mixtures when interfering effects need to be counterbalanced: relative errors in determination of individual ions can be decreased typically from 25% to less than 5%, if compared to the use of a single proposed ion-selective electrode.

  19. Structure and properties of 2-cyanopyridinium perchlorate [2-CNPyH][ClO4

    Science.gov (United States)

    Czupinski, O.; Wojtas, M.; Zaleski, J.; Jakubas, R.; Medycki, W.

    2006-03-01

    The crystal structure of 2-cyanopyridinium perchlorate, [2-CNPyH][ClO4], has been determined at 100 (phase II) and 293 K (phase I). It is monoclinic P 21 at 100 K and orthorhombic P 212121 at 293 K. The dynamic properties of the crystal were studied by differential scanning calorimetry, dilatometry, pyroelectric, dielectric, proton (1H NMR), chlorine (35Cl NMR) magnetic resonance spectroscopies and the infrared method. The crystal undergoes a structural phase transition (\\mathrm {I\\rightarrow II} ) at 170 K characterized by a complex mechanism involving both 'order-disorder' and 'displacive' contributions. It reveals pyroelectric properties below 170 K. The dielectric relaxation existing over phase I is due to the motion of the cyano group, whereas the dynamics of the [ClO4]- anions is reflected in the significant dielectric increment around the \\mathrm {I\\rightarrow II} phase transition.

  20. Structure and properties of 2-cyanopyridinium perchlorate [2-CNPyH][ClO4

    International Nuclear Information System (INIS)

    The crystal structure of 2-cyanopyridinium perchlorate, [2-CNPyH][ClO4], has been determined at 100 (phase II) and 293 K (phase I). It is monoclinic P 21 at 100 K and orthorhombic P 212121 at 293 K. The dynamic properties of the crystal were studied by differential scanning calorimetry, dilatometry, pyroelectric, dielectric, proton (1H NMR), chlorine (35Cl NMR) magnetic resonance spectroscopies and the infrared method. The crystal undergoes a structural phase transition (I →II) at 170K characterized by a complex mechanism involving both 'order-disorder' and 'displacive' contributions. It reveals pyroelectric properties below 170K. The dielectric relaxation existing over phase I is due to the motion of the cyano group, whereas the dynamics of the [ClO4]- anions is reflected in the significant dielectric increment around the I →II phase transition

  1. Degradation study of trichloroethylene and perchloric ethylene using high energy electron beam generated in industrial accelerator

    International Nuclear Information System (INIS)

    The pollution of potable water with chlorinated hydrocarbons, mainly trichloroethylene (TCE) and perchloric ethylene (PCE), is seriously increasing the problem of contamination of water, specially in highly industrialized areas. Recent studies show that depuration by ionizing radiation has been considered a possible alternative to the control of water pollution, wherein the process by ionizing radiation converts TCE and PCE into approximately 100% carbon dioxide ions. Water samples containing TCE e PCE were submitted to radiation in the pilot plant installed in the industrial electron accelerator at IPEN from Radiation Dynamics, Dynamitron II, of 1,5 MeV - 25 m A, with doses varying from 2 kGy to 8 kGy, being its parameters analyzed before and after irradiation TCE and PCE concentrations were determined by the gas chromatography method by liquid-liquid extraction using a gas chromatograph, model CG 90, with an electron capture detector. (author). 5 refs, 4 figs

  2. Thyroid scintigraphy and perchlorate discharge test in the diagnosis of congenital hypothyroidism

    International Nuclear Information System (INIS)

    Quantitative thyroid scanning using low doses of technetium-99m sodium pertechnetate was performed on 147 infants (55 males and 92 females) with congenital hypothyroidism detected through the national neonatal screening programme. Thirty-two (21.8%) were athyrotic, while 62 (42.2%) had an ectopic thyroid and 53 (36%) had a eutopic gland with increased 99mTc uptake (mean 17%; range, 5%-38%). The perchlorate discharge test (PDT) was performed in nine of the infants with ectopic glands and 15 with eutopic glands; the findings were consistent with an organification defect in 22 cases (seven ectopic and 15 eutopic). Thyroid scintigraphy and PDT can add useful aetiological, genetic and prognostic information in the clinical evaluation of infants with congenital hypothyroidism detected by neonatal screening. (orig.). With 4 figs., 1 tab

  3. Promethium-147 extraction with 1,1-diantipyrylalkanes from perchlorate solutions

    International Nuclear Information System (INIS)

    Conditions for quantitative extraction of indicator amounts of promethium-147 from perchlorate solutions with 1,1-diantipyrylalkanes are found. The composition of oxtracted complexes is identified. Extraction concentration constants are calculated. The dependence between the extraction capacity and reagent structure is established. Promethium-147 is used as a radioactive label when studying La3+, Ce3+, Pr3+, Nd3+, Sm3+, Lu3+ extraction. The concentration constants of r.e.e. extraction with diantipyrylmethane are 3.1x1010; 3.5x1010; 3.5x1010; 3.8x1010; 4.0x1010; 6.2x1010, respectively, when μ=0.2

  4. Non-aqueous titrimetric assay of gabapentin in capsules using perchloric acid as titrant

    Directory of Open Access Journals (Sweden)

    SAMEER A.M. ABDULRAHMAN

    2011-06-01

    Full Text Available Two simple, rapid, accurate and inexpensive methods using visual and potentiometric titrimetric techniques are described for the determination of gabapentin (GBP in bulk drug as well as in capsules. The methods are based on the neutralization reaction of the primary amino group of GBP with acetous perchloric acid as titrant in anhydrous acetic acid medium. The end point was detected either visually using crystal violet as indicator or potentiometrically using a modified glass electrode SCE electrode system. Both methods are applicable over the range 1.0-16.0 mg of GBP and the titration reaction follows a 1:1 stoichiometry. The methods were successfully applied to the determination of GBP in capsules. The validity of the proposed methods was further ascertained by parallel determination by a reference method and by recovery studies via standard-addition technique.

  5. Thyroid scintigraphy and perchlorate discharge test in the diagnosis of congenital hypothyroidism

    Energy Technology Data Exchange (ETDEWEB)

    El-Desouki, M. [Dept. of Medicine, King Saud Univ., Riyadh (Saudi Arabia); Al-Jurayyan, N. [Dept. of Paediatrics, King Saud Univ., Riyadh (Saudi Arabia); Al-Nuaim, A. [Div. of Endocrinology, King Saud Univ., Riyadh (Saudi Arabia); Al-Herbish, A. [Dept. of Paediatrics, King Saud Univ., Riyadh (Saudi Arabia); Abo-Bakr, A. [Dept. of Paediatrics, King Saud Univ., Riyadh (Saudi Arabia); Al-Mazrou, Y. [Ministry of Health, Riyadh (Saudi Arabia); Al-Swailem, A. [Ministry of Health, Riyadh (Saudi Arabia)

    1995-09-01

    Quantitative thyroid scanning using low doses of technetium-99m sodium pertechnetate was performed on 147 infants (55 males and 92 females) with congenital hypothyroidism detected through the national neonatal screening programme. Thirty-two (21.8%) were athyrotic, while 62 (42.2%) had an ectopic thyroid and 53 (36%) had a eutopic gland with increased {sup 99m}Tc uptake (mean 17%; range, 5%-38%). The perchlorate discharge test (PDT) was performed in nine of the infants with ectopic glands and 15 with eutopic glands; the findings were consistent with an organification defect in 22 cases (seven ectopic and 15 eutopic). Thyroid scintigraphy and PDT can add useful aetiological, genetic and prognostic information in the clinical evaluation of infants with congenital hypothyroidism detected by neonatal screening. (orig.). With 4 figs., 1 tab.

  6. Effect of Microwave Heating on the Leaching of Lateritic Nickel Ore in Perchloric Acid

    International Nuclear Information System (INIS)

    In this study, the leaching conditions of Sivrihisar (Adatepe) limonite type lateritic ore in acidic medium were investigated. Leaching experiments were carried out using conventional and microwave-assisted method. The effects of stirring speed, leaching temperature, perchloric acid concentration, solid/liquid ratio and particle size on conventional leaching were determined. Microwave-assisted leaching was carried out by using the optimum results of the conventional leaching. The pre-heating process was applied on different microwave powers (0, 90, 180, 360 and 600 W) and pre-processing time (0, 1, 3, 5, 7, 10, 15 and 20 min). These experimental results demonstrated that acid leaching was a convenient method for Ni extraction from lateritic ore. The higher dissolution and the higher Ni recoveries in the microwave-assisted leaching process were obtained in less leach time. (author)

  7. Hydration of some trivalent metal ions extracted as perchlorates with trioctylphosphine oxide in hexane

    International Nuclear Information System (INIS)

    Perchlorates of Sc3+, Y3+, La3+, and Eu3+ have each been extracted from 0.1 mol x dem-3 aqueous solution of μ=1 with trioctylphosphine oxide (TOPO) in hexane. The hydration number of the extracted salts has been determined by Karl Fischer titration. Sc3+, Y3+, and Eu3+ are extracted as the tetra- and hexa-solvates of TOPO but the assumption of octa-solvate on addition to the tetra-solvate explains the extraction data of La3+ well. The hydration number of tetra-solvates is 2(Sc3+ and Eu3+), 3(Y3+) and probably 4 for La3+ ion. That of hexa-and octa-solvates is 4-5. (author)

  8. Hydration and Solvation of Metal Perchlorates Extracted with Trioctylphosphine Oxide in Hexane

    International Nuclear Information System (INIS)

    Perchlorates of Sc3+, Y3+, La3+, and Eu3+ have each been extracted from 0.1 mol dm-3 aqueous solution of μ=1 with trioctylphosphine oxide (TOPO) in hexane. The hydration number of the extracted salts has been determined by Karl Fischer titration. Sc3+, Y3+, and Eu3+ are extracted as the tetra- and hexa-solvates of TOPO but the assumption of octa-solvate on addition to the tetra-solvate explains the extraction data of La3+ well. The hydration number of tetra-solvates is 2 (Sc3+ and Eu3+), 3 (Y3+) and probably 4 for La3+ ion. That of hexa-and octa- solvates is 4-5. (author). 1 tabs

  9. Extraction of lanthanide and scandium perchlorates by podands bearing diphenylphosphorylacetamide terminal groups

    International Nuclear Information System (INIS)

    Interphase distribution of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,Y and Sc perchlorate trace amounts between HClO4 aqueous solutions and phosphorus-containing podands with two end groups Ph2P(O)CH2C(O)NH- connected by di- and triethylene glycol chain in dichlorethane has been studied. Stoichiometry of extracted complexes is determined, effect of HClO4 concentration in aqueous phase and nature of organic solvent on the efficiency of metal ion transitions in organic phase are treated. Studied compounds reveal higher extraction ability regarding to metal ions in HClO4 solutions as compared with the same ability of (dibutylcarbamoylmethyl)diphenylphosphine oxide. Possibility for the using macroporous polymer sorbents impregnated by studied podands for the separation and concentration of rare earth(III) and Sc(III) ions from aqueous solutions containing ClO4- anions has been demonstrated

  10. A Consideration for Design of Ammonium Perchlorate/Hydroxyl Terminated Polybutadiene Composite Propellant

    Science.gov (United States)

    Kohga, Makoto

    Specific impulse and burning rate characteristics are the important properties for the propellant design. Because of the requirements for the preparation of ammonium perchlorate (AP)/hydroxyl-terminated polybutadiene (HTPB) composite propellant, there is an upper limit content, φ of AP contained propellant. Specific impulse and burning rate increase with increasing the AP content. The specific impulse, Ispφ and the burning rate, rφ of the propellant prepared at φ, rφ are the highest values of the propellant prepared with AP used as an oxidizer. It is necessary for the propellant design to estimate φ, Ispφ and rφ. The φ, Ispφ and rφ are closely associated with the specific surface area, Swp measured by air-permeability method. Therefore, these values are estimated with Swp. A process for the design of AP/HTPB composite propellant would be proposed in this study.

  11. Large Angular Jump Mechanism Observed for Hydrogen Bond Exchange in Aqueous Perchlorate Solution

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Minbiao; /SLAC, PULSE /Stanford U., Phys. Dept.; Odelius3, Michael; /Stockholm U.; Gaffney1, K.J.; /aff SLAC, PULSE

    2010-06-11

    The mechanism for hydrogen bond (H-bond) switching in solution has remained subject to debate despite extensive experimental and theoretical studies. We have applied polarization-selective multidimensional vibrational spectroscopy to investigate the H-bond exchange mechanism in aqueous NaClO{sub 4} solution. The results show that a water molecule shifts its donated H-bonds between water and perchlorate acceptors by means of large, prompt angular rotation. Using a jump-exchange kinetic model, we extract an average jump angle of 49 {+-} 4{sup o}, in qualitative agreement with the jump angle observed in molecular dynamics simulations of the same aqueous NaClO{sub 4} solution.

  12. Complexes of rare-earth perchlorates with ditbutyl amides of di, tri and tetraglycolic acids

    OpenAIRE

    Premlatha, C; Soundararajan, S

    1981-01-01

    New complexes of lanthanide perchlorates with di-t-butyl amides of di, tri and tetraglycolic acids have been synthesised. The complexes have the general formula Ln(DiGA)3(ClO4)3; Ln(TriGA)2 (ClO4)3 and Ln(TetGA)2 (C1O4)3, where Ln = La-Yb and Y and DiGA = N,N′, di-t-butyl diglycolamide, TriGA N,N′, di-t-butyl triglycolamide and TetGA = N,N′ di-t-butyl tetraglycolamide, respectively. The complexes have been characterized by analysis, electrolytic conductance, infrared,1H and13C nuclear magneti...

  13. CALCIUM SOAP LUBRICANTS

    OpenAIRE

    Alaz, Izer; Tugce, Nefise; Devrim, Balköse

    2014-01-01

    The article studies the properties of calcium stearate (CaSt2) and lubricants produced on its basis. These lubricants were prepared using sodium stearate and calcium chloride by subsidence from aqueous solutions. The CaSt2 and the light fraction of crude oil were mixed together to obtain lubricating substances. The article shows that CaSt2 had the melting temperature of 142.8 C that is higher than the melting temperature of crude oil (128 C). The compositions of obtained lubricants were stu...

  14. Effect of Perchlorates on Electron Radiolysis of Glycine with Application to Mars

    Science.gov (United States)

    Góbi, Sándor; Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-05-01

    This work explores the radiolytic decomposition of glycine (H2NCH2COOH) under simulated Martian conditions in the presence of perchlorates ({{{ClO}}4}-), which are abundant oxidizers on the surface of Mars, by energetic electrons at 10, 160, 210, and 260 K, mimicking the radiation exposure of the Martian regolith in the first 5-10 cm depths over about 250 million years. Our experiments present quantitative evidence that the rate constants of the glycine decomposition in the presence of magnesium perchlorate hexahydrate (Mg(ClO4)2 · 6H2O) were a factor of about two higher than that of the pure glycine, suggesting that energetic oxygen atoms (O) released from the {{{ClO}}4}- have a significant effect on the decomposition rates and accelerate them by providing a unique oxidizing environment in the radiolyzed samples. Hence, two decay mechanisms exist: radiolysis by the electrons and oxidation by the O atoms. Within the Mars-relevant temperature range covering 160-260 K, the destruction rates are nearly temperature invariant with rates varying as little as 5%. Further, the formation rates of carbon dioxide (CO2) and carbon monoxide (CO) are both accelerated in the presence of {{{ClO}}4}- by a factor of three to five, supporting our conclusion of an active oxygen-initiated chemistry. In addition, the degradation rates are significantly higher than the formation rates of CO2 and CO. This suggests that, besides the decarboxylation, alternative degradation pathways such as a polymerization of glycine must exist. Finally, besides CO2 and CO, three alternative products were identified tentatively: methylamine (CH3NH2), methane (CH4), and ammonia (NH3).

  15. CALCIUM-INDUCED SUPRAMOLECULAR STRUCTURES IN THE CALCIUM CASEINATE SYSTEM

    Science.gov (United States)

    The molecular details deciphering the spontaneous calcium-induced protein aggregation process in the calcium caseinate system remain obscure. Understanding this complex process could lead to potential new applications of this important food ingredient. In this work, we studied calcium-induced supra...

  16. METHOD 332.0: DETERMINATION OF PERCHLORATE IN DRINKING WATER BY ION CHROMATOGRAPHY WITH SUPPRESSED CONDUCTIVITY AND ELECTROSPRAY IONIZATION MASS SPECTROMETRY

    Science.gov (United States)

    This method is applicable to the identification and quantitation of perchlorate in raw and finished drinking waters. The approach used is ion chromatography with suppressed conductivity and electrospray ionization mass spectrometry (IC-ESI/MS)

  17. A sensor for calcium uptake

    OpenAIRE

    Collins, Sean; Meyer, Tobias

    2010-01-01

    Mitochondria — the cell’s power plants — increase their energy production in response to calcium signals in the cytoplasm. A regulator of the elusive mitochondrial calcium channel has now been identified.

  18. Children's Bone Health and Calcium

    Science.gov (United States)

    ... Trials Resources and Publications Children's Bone Health and Calcium: Condition Information Skip sharing on social media links ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  19. Calcium ion channel and epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yudan Lü; Weihong Lin; Dihui Ma

    2006-01-01

    OBJECTIVE: To review the relationship between calcium ion channel and epilepsy for well investigating the pathogenesis of epilepsy and probing into the new therapeutic pathway of epilepsy.DATA SOURCES: A computer-based online research Calcium ion channel and epilepsy related articles published between January 1994 and December 2006 in the CKNI and Wanfang database with the key words of "calcium influxion, epilepsy, calcium-channel blocker". The language was limited to Chinese. At the same time,related articles published between January 1993 and December 2006 in Pubmed were searched for on online with the key words of "calcium influxion, epilepsy" in English.STUDY SELECTION: The materials were selected firstly. Inclusive criteria: ① Studies related to calcium ion channel and the pat1hogenesis of epilepsy. ② Studies on the application of calcium ion channel blocker in the treatment of epilepsy. Exclusive criteria: repetitive or irrelated studies.DATA EXTRACTION: According to the criteria, 123 articles were retrieved and 93 were excluded due to repetitive or irrelated studies. Altogether 30 articles met the inclusive criteria, 11 of them were about the structure and characters of calcium ion channel, 10 about calcium ion channel and the pathogenesis of epilepsy and 9 about calcium blocker and the treatment of epilepsy.DATA SYNTHESIS: Calcium ion channels mainly consist of voltage dependent calcium channel and receptor operated calcium channel. Depolarization caused by voltage gating channel-induced influxion is the pathological basis of epileptic attack, and it is found in many studies that many anti-epileptic drugs have potential and direct effect to rivalizing voltage-dependent calcium ion channel.CONCLUSION: Calcium influxion plays an important role in the seizure of epilepsy. Some calcium antagonists seen commonly are being tried in the clinical therapy of epilepsy that is being explored, not applied in clinical practice. If there are enough evidences to

  20. Solar Imagery - Chromosphere - Calcium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about...

  1. Impregnating Coal With Calcium Carbonate

    Science.gov (United States)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.

    1991-01-01

    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  2. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

    Alexander, R Todd; Cordat, Emmanuelle; Chambrey, Régine;

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and...... renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis....

  3. Thermal Diffusivity and Specific Heat Measurements of Titanium Potassium Perchlorate Titanium Subhydride Potassium Perchlorate 9013 Glass 7052 Glass SB-14 Glass and C-4000 Muscovite Mica Using the Flash Technique.

    Energy Technology Data Exchange (ETDEWEB)

    Specht, Paul Elliott; Cooper, Marcia A.

    2015-02-01

    The flash technique was used to measure the thermal diffusivity and specific heat of titanium potassium perchlorate (TKP) ignition powder (33wt% Ti - 67wt% KP) with Ventron sup- plied titanium particles, TKP ignition powder (33wt% Ti - 67wt% KP) with ATK supplied titanium particles, TKP output powder (41wt% Ti - 59wt% KP), and titanium subhydride potassium perchlorate (THKP) (33wt% TiH 1.65 - 67wt% KP) at 25 o C. The influence of density and temperature on the thermal diffusivity and specific heat of TKP with Ventron supplied titanium particles was also investigated. Lastly, the thermal diffusivity and specific heats of 9013 glass, 7052 glass, SB-14 glass, and C-4000 Muscovite mica are presented as a function of temperature up to 300 o C.

  4. Acute and chronic activity of perchlorate and hexavalent chromium contamination on the survival and development of Culex quinquefasciatus Say (Diptera: Culicidae)

    International Nuclear Information System (INIS)

    Effects of water contamination with perchlorate and hexavalent chromium [Cr (VI)] on the mosquito Culex quinquefasciatus were assessed. The chronic (10-day) LC5s values for perchlorate and chromium were 74 ± 8.0 mg/L and 0.41 ± 0.15 mg/L, respectively. Relative Growth Index, a measure of growth and mortality rates in a population, was significantly reduced within 5 days for levels of perchlorate as low as 25 mg/L and for levels of chromium as low as 0.16 mg/L. Neither compound altered wing length of surviving adults. In combination, contaminants were synergistic, causing 14% more mortality than predicted. Acute (24-h) LC5 values for perchlorate and Cr (VI) were 17,000 ± 3200 and 38 ± 1.3 mg/L, respectively. Effects on mosquito larvae in contaminated environments are likely to be observed for Cr (VI) but not for perchlorate, which generally does not occur at levels as high as those shown here to affect larval mosquitoes. - While pollution with hexavalent chromium may adversely affect Culex quinquefasciatus larvae, levels of perchlorate currently in the environment will not impact these insects

  5. Acute and chronic activity of perchlorate and hexavalent chromium contamination on the survival and development of Culex quinquefasciatus Say (Diptera: Culicidae)

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, Mary A. [Department of Entomology, University of California, Riverside, CA 92521 (United States)]. E-mail: mary.sorensen@email.ucr.edu; Jensen, Peter D. [Department of Entomology, University of California, Riverside, CA 92521 (United States); Walton, William E. [Department of Entomology, University of California, Riverside, CA 92521 (United States); Trumble, John T. [Department of Entomology, University of California, Riverside, CA 92521 (United States)

    2006-12-15

    Effects of water contamination with perchlorate and hexavalent chromium [Cr (VI)] on the mosquito Culex quinquefasciatus were assessed. The chronic (10-day) LC{sub 5}s values for perchlorate and chromium were 74 {+-} 8.0 mg/L and 0.41 {+-} 0.15 mg/L, respectively. Relative Growth Index, a measure of growth and mortality rates in a population, was significantly reduced within 5 days for levels of perchlorate as low as 25 mg/L and for levels of chromium as low as 0.16 mg/L. Neither compound altered wing length of surviving adults. In combination, contaminants were synergistic, causing 14% more mortality than predicted. Acute (24-h) LC{sub 5} values for perchlorate and Cr (VI) were 17,000 {+-} 3200 and 38 {+-} 1.3 mg/L, respectively. Effects on mosquito larvae in contaminated environments are likely to be observed for Cr (VI) but not for perchlorate, which generally does not occur at levels as high as those shown here to affect larval mosquitoes. - While pollution with hexavalent chromium may adversely affect Culex quinquefasciatus larvae, levels of perchlorate currently in the environment will not impact these insects.

  6. Poly[[tetrakis(μ2-pyrazine N,N′-dioxide-κ2O:O′erbium(III] tris(perchlorate

    Directory of Open Access Journals (Sweden)

    James D. Buchner

    2010-09-01

    Full Text Available The title three-dimensional coordination network, {[Er(C4H4N2O24](ClO43}n, is isostructural to that of other lanthanides. The Er+3 cation lies on a fourfold roto-inversion axis. It is coordinated in a distorted square-antiprismatic fashion by eight O atoms from bridging pyrazine N,N′-dioxide ligands. There are two unique pyrazine N,N′-dioxide ligands. One ring is located around an inversion center, and there is a a twofold rotation axis at the center of the other ring. There are also two unique perchlorate anions. One is centered on a twofold rotation axis and the other on a fourfold roto-inversion axis. The perchlorate anions are located in channels that run perpendicular to (001 and (110 and interact with the coordination network through C—H...O hydrogen bonds.

  7. Bis(μ-bis{[4-(2-pyridylpyrimidin-2-yl]sulfanyl}methanedisilver(I bis(perchlorate

    Directory of Open Access Journals (Sweden)

    Hai-Bin Zhu

    2010-12-01

    Full Text Available In the macrocyclic centrosymmetric dinuclear complex, [Ag2(C19H14N6S22](ClO42, the AgI atom, bis{[4-(2-pyridylpyrimidin-2-yl]sulfanyl}methane (2-bppt ligand and perchlorate anion each lie on a twofold rotation axis. The 2-bppt ligand chelates two four-coordinated AgI atoms through its two bipyridine-like arms. The O atoms of the perchlorate anion are disordered each over two positions of equal occupancy. Adjacent complex molecules are linked by π–π interactions between the pyridine and pyrimidine rings [centroid–centroid distance = 3.663 (8 Å].

  8. Poly[[tetrakis(μ2-pyrazine N,N′-dioxide-κ2O:O′holmium(III] tris(perchlorate

    Directory of Open Access Journals (Sweden)

    James D. Buchner

    2010-09-01

    Full Text Available The title three-dimensional coordination network, {[Ho(C4H4N2O24](ClO43}n, is isostructural to that of other lanthanides. The Ho+3 cation lies on a fourfold roto-inversion axis. It is coordinated in a distorted square anti-prismatic fashion by eight O atoms from bridging pyrazine N,N′-dioxide ligands. There are two unique pyrazine N,N′-dioxide ligands. One ring is located around an inversion center, and there is a a twofold rotation axis at the center of the other ring. There are also two unique perchlorate anions. One is centered on a twofold rotation axis and the other on a fourfold roto-inversion axis. The perchlorate anions are located in channels that run perpendicular to (001 (110 and interact with the coordination network through C—H...O hydrogen bonds.

  9. Reactions between cerium(IV) and methyl-6-x-derivatives of aniline in perchloric acid solutions

    International Nuclear Information System (INIS)

    The oxidation of 2,6-dimethyl-, 2-isopropyl-6-methyl, 2-chloro-6-methyl-and 2-methyl-6-nitro aniline with cerium(IV) in perchloric acid solutions has been examined. It has been found that the concentration of hydrogen ions and the basicity of nitrogen atom in the amine group decide about the resultant intermediate products. Some of these products can be practically prepared using cerium(IV) as an oxidizing agent. (author). 16 refs, 1 tab

  10. X-ray, vibrational spectra and quantum chemical studies on a new semiorganic crystal: 4-Chloroanilinium perchlorate

    Science.gov (United States)

    Anitha, R.; Athimoolam, S.; Gunasekaran, M.; Anitha, K.

    2014-11-01

    A new semi-organic material 4-chloroanilinium perchlorate was synthesized and grown as a single crystal by slow evaporation solution growth technique. A good X-ray quality single crystal was selected from the grown crops and used for the single crystal diffraction studies. The asymmetric part of the unit cell contains a 4-chloroanilinium cation and a perchlorate anion. The protonation on the N site of the chloroaniline is confirmed from the CN bond distance and the deprotonation on perchloric acid is confirmed from ClO bond geometry. The molecular aggregations are stabilized through intricate three dimensional hydrogen bonding network formed by the classical NH⋯O hydrogen bonds. It form two infinite chains running along the b-axis of the unit cell which are cross-linked through another NH⋯O bond leading to alternate ring R44(12) motifs. These ring and chain motifs lead to alternate hydrophilic and hydrophobic layers along c-axis of the unit cell. The presence of different functional groups and the nature of their vibrations were identified in experimental vibrational studies through Infra-Red and Raman measurements in the range of 4000-400 cm-1. The optimized molecular structure, vibrational mode, computed spectra, molecular properties and NBO analysis of the 4-chloroanilinium perchlorate were found out by quantum chemical calculations with HF and DFT/B3LYP methods invoking 6-311++G(d,p) basis sets. Computed geometrical parameters and harmonic frequencies of fundamental, combination and overtone transitions were found in satisfactory agreement with the experimental data. The electronic properties such as HOMO and LUMO energies were carried out.

  11. Evaluation of the Protective Effects of Emilia sonchifolia Linn. (DC.) on Perchlorate-Induced Oxidative Damage

    OpenAIRE

    D. Gayathri Devi; Y. Lija; T.R. Cibin; Biju, P.G.; V. Gayathri Devi; Annie Abraham

    2006-01-01

    Emilia sonchifolia Linn. (DC.) is a traditionally used medicinal plant seen in most tropical and subtropical regions worldwide. Various parts of the plant are used for the treatment of diseases like asthma, intermittent fevers, breast cancer, ophthalmia, nyctalopia etc. We have isolated the flavonoid fraction from E. sonchifolia (whole plant). Female albino rats were fed with 0.2% sodium perchlorate to induce oxidative stress. The flavonoid fraction of the plant was fed along with sodium perc...

  12. 2,5-Bis[2-({bis[3-(dimethylazaniumylpropyl]azaniumyl}methylphenyl]-1,3,4-oxadiazole hexakis(perchlorate sesquihydrate

    Directory of Open Access Journals (Sweden)

    Vieri Fusi

    2012-12-01

    Full Text Available In the title hydrated salt, C36H66N8O6+·6ClO4−·1.5H2O, the asymmetric unit consists of a hexaprotonated [H6L]6+ cation, five perchlorate anions in general positions, two on twofold rotation axes (one of which is disordered, and two water molecules of crystallization in general positions, one of them disordered around a twofold crystallographic axis. In the [H6L]6+ cation, two strong intramolecular N—H...N hydrogen bonds occur, involving the N atoms of the oxadiazole ring as acceptors and the closest NH+ groups of each dipropylenetriamine unit. In the crystal, the [H6L]6+ cations form channels along the a-axis direction, in which the perchlorate counter-ions and the water molecules are lodged. The crystal packing features a network of N—H...O and O—H...O hydrogen bonds involving the NH+ groups of the [H6L]6+ cation, the perchlorate anions and the water molecules.

  13. Microbial respiration with chlorine oxyanions: diversity and physiological and biochemical properties of chlorate- and perchlorate-reducing microorganisms.

    Science.gov (United States)

    Liebensteiner, Martin G; Oosterkamp, Margreet J; Stams, Alfons J M

    2016-02-01

    Chlorine oxyanions are valuable electron acceptors for microorganisms. Recent findings have shed light on the natural formation of chlorine oxyanions in the environment. These suggest a permanent introduction of respective compounds on Earth, long before their anthropogenic manufacture. Microorganisms that are able to grow by the reduction of chlorate and perchlorate are affiliated with phylogenetically diverse lineages, spanning from the Proteobacteria to the Firmicutes and archaeal microorganisms. Microbial reduction of chlorine oxyanions can be found in diverse environments and different environmental conditions (temperature, salinities, pH). It commonly involves the enzymes perchlorate reductase (Pcr) or chlorate reductase (Clr) and chlorite dismutase (Cld). Horizontal gene transfer seems to play an important role for the acquisition of functional genes. Novel and efficient Clds were isolated from microorganisms incapable of growing on chlorine oxyanions. Archaea seem to use a periplasmic Nar-type reductase (pNar) for perchlorate reduction and lack a functional Cld. Chlorite is possibly eliminated by alternative (abiotic) reactions. This was already demonstrated for Archaeoglobus fulgidus, which uses reduced sulfur compounds to detoxify chlorite. A broad biochemical diversity of the trait, its environmental dispersal, and the occurrence of relevant enzymes in diverse lineages may indicate early adaptations of life toward chlorine oxyanions on Earth. PMID:26104311

  14. Fruit Calcium: Transport and Physiology

    Science.gov (United States)

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  15. Fruit Calcium: Transport and Physiology.

    Science.gov (United States)

    Hocking, Bradleigh; Tyerman, Stephen D; Burton, Rachel A; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  16. Calcium and calcitonin responses to calcium infusion in type I diabetes mellitus.

    OpenAIRE

    Amado, J. A.; C. Gomez; Obaya, S.; Otero, M; Gonzalez-Macias, J

    1987-01-01

    We studied calcium and calcium and calcitonin responses to intravenous calcium infusion (3 mg of elemental calcium/kg of body weight in 10 minutes) in 21 type I diabetic males and 17 age-matched normal males. Baseline total calcium, parathyroid hormone and calcitonin levels were normal in the diabetic group, but ionized calcium was lowered. Cortical bone status and osteocalcin levels were normal, suggesting a normal osteoblastic function. Total calcium and ionized calcium responses to calcium...

  17. DISTILLATION OF CALCIUM

    Science.gov (United States)

    Barton, J.

    1954-07-27

    This invention relates to an improvement in the process for the purification of caicium or magnesium containing an alkali metal as impurity, which comprises distiiling a batch of the mixture in two stages, the first stage distillation being carried out in the presence of an inert gas at an absolute pressure substantially greater than the vapor pressure of calcium or maguesium at the temperature of distillation, but less than the vaper pressure at that temperature of the alkali metal impurity so that only the alkali metal is vaporized and condensed on a condensing surface. A second stage distilso that substantially only the calcium or magnesium distills under its own vapor pressure only and condenses in solid form on a lower condensing surface.

  18. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James

    2016-01-01

    This book discusses the ways in which mathematical, computational, and modelling methods can be used to help understand the dynamics of intracellular calcium. The concentration of free intracellular calcium is vital for controlling a wide range of cellular processes, and is thus of great physiological importance. However, because of the complex ways in which the calcium concentration varies, it is also of great mathematical interest.This book presents the general modelling theory as well as a large number of specific case examples, to show how mathematical modelling can interact with experimental approaches, in an interdisciplinary and multifaceted approach to the study of an important physiological control mechanism. Geneviève Dupont is FNRS Research Director at the Unit of Theoretical Chronobiology of the Université Libre de Bruxelles;Martin Falcke is head of the Mathematical Cell Physiology group at the Max Delbrück Center for Molecular Medicine, Berlin;Vivien Kirk is an Associate Professor in the Depar...

  19. Removal of toxic ions (chromate, arsenate, and perchlorate) using reverse osmosis, nanofiltration, and ultrafiltration membranes

    KAUST Repository

    Yoon, Jaekyung

    2009-09-01

    Rejection characteristics of chromate, arsenate, and perchlorate were examined for one reverse osmosis (RO, LFC-1), two nanofiltration (NF, ESNA, and MX07), and one ultrafiltration (UF and GM) membranes that are commercially available. A bench-scale cross-flow flat-sheet filtration system was employed to determine the toxic ion rejection and the membrane flux. Both model and natural waters were used to prepare chromate, arsenate, and perchlorate solutions (approximately 100 μg L-1 for each anion) in mixtures in the presence of other salts (KCl, K2SO4, and CaCl2); and at varying pH conditions (4, 6, 8, and 10) and solution conductivities (30, 60, and 115 mS m-1). The rejection of target ions by the membranes increases with increasing solution pH due to the increasingly negative membrane charge with synthetic model waters. Cr(VI), As(V), and ClO4 - rejection follows the order LFC-1 (>90%) > MX07 (25-95%) ≅ ESNA (30-90%) > GM (3-47%) at all pH conditions. In contrast, the rejection of target ions by the membranes decreases with increasing solution conductivity due to the decreasingly negative membrane charge. Cr(VI), As(V), and ClO4 - rejection follows the order CaCl2 < KCl ≅ K2SO4 at constant pH and conductivity conditions for the NF and UF membranes tested. For natural waters the LFC-1 RO membrane with a small pore size (0.34 nm) had a significantly greater rejection for those target anions (>90%) excluding NO3 - (71-74%) than the ESNA NF membrane (11-56%) with a relatively large pore size (0.44 nm), indicating that size exclusion is at least partially responsible for the rejection. The ratio of solute radius (ri,s) to effective membrane pore radius (rp) was employed to compare ion rejection. For all of the ions, the rejection is higher than 70% when the ri,s/rp ratio is greater than 0.4 for the LFC-1 membrane, while for di-valent ions (CrO4 2 -, SO4 2 -, and HAsSO4 2 -) the rejection (38-56%) is fairly proportional to the ri,s/rp ratio (0.32-0.62) for the ESNA

  20. Perchlorate production by ozone oxidation of chloride in aqueous and dry systems

    International Nuclear Information System (INIS)

    Overwhelming evidence now exists that perchlorate is produced through natural processes and can be ubiquitously found at environmentally relevant concentrations in arid and semi-arid locations. A number of potential production mechanisms have been hypothesized and ClO4- production by ozone oxidation of surface bound Cl- was demonstrated. However, no information concerning the impact of concentration, final reaction products distribution, impact of reaction phase, or oxidation of important oxychlorine intermediates has been reported. Using IC-MS-MS analysis and replicate oxidation experiments, we show that exposing aqueous solutions or Cl- coated sand or glass surfaces to O3 (0.96%) generated ClO4- with molar yields of 0.007 and 0.01% for aqueous Cl- solutions and 0.025 and 0.42% for Cl- coated sand and glass, respectively. Aqueous solutions of Cl- produced less ClO4- than Cl- coated sand or glass as well as a higher ratio of ClO3- to ClO4-. Reduction of the initial Cl- mass resulted in substantially higher molar yields of ClO4- and ClO3-. In addition, alkaline absorbers that captured gaseous products contained substantial quantities of Cl-, ClO3-, and ClO4-. Solutions of possible oxychlorine intermediates (OCl- and ClO3-) exposed to O3 produced only scant amounts of ClO4- while a ClO2- solution exposed to O3 produced substantial molar yields of ClO4- (4% molar yield). Scanning electron microscopy coupled with energy energy-dispersive X-ray analysis demonstrated a significant loss of Cl- and an increase in oxygen on the Cl- coated silica sand exposed to O3. While the experimental conditions are not reflective of natural conditions this work clearly demonstrates the relative potential of Cl- precursors in perchlorate production and the likely importance of dry aerosol oxidation over solution phase reactions. It also suggests that ClO2- may be a key intermediate while ClO3- and OCl- are unlikely to play a significant role

  1. Anomalous aryl strengthening of complexes at americium and europium extraction with alkylenediphospine dioxide from perchloric media

    International Nuclear Information System (INIS)

    Studied was the extraction of americium(3) and europium(3) from perchlorate solutions(0.001 M) with dioxides of alkylenediphosphines of three types: aryl Ph2P(O)CH2(O)PPh2(briefly 4P), and Ph2P(O)(CH2)2(O)PPh2, mixed Ph2P(O)CH2(O)P(C8H17)2 (or 2Ph2Oct) and alkyl (C8H17)2P(O)CH2(O)P(C8H17)2 (or 4 Oct). Trisolvates of MeS3x(ClO4)3 are predominantly formed but americium disolvates are also present upon dilution with dichloroethane. For 4Ph,2Ph2Oct and 4 Oct the concentration is, respectively, 1015, 2x1014, and 1013; for disolvates by 4 orders of magnitude lower which is, nevertheless, by 2 orders of magnitude higher than for nitric acid solutions. The separation coefficient of β Am/Eu for 4Ph attains 6-8. As in the case of nitrate solutions, an anomalous aryl strengthening of the complexes is observed: an increase in the distribution coefficients and extraction constants in the series of 4 Oct - 2Ph 2 Oct - 4Ph, in spite of the introduction of electronegative aryl substituents into the dioxide molecule, which reduce electron density on oxygen atoms and basicity of dioxides. In contrast to nitric acid solutions, observed is a nonlinear effect of a change in basicity on extraction properties upon dilution with dichloroethane (dioxide of 2Ph2 Oct does not occupy an intermediate position but is close to 4Ph). Upon dilution with chloroform the dependence is linear and anomalous effect rises due to a different nature of interactions of dioxides with chloroform. When the bridge increases up to ethylene, an anomalous strengthening of the complexes disappears. However, the distribution coefficients upon extraction with alkyl dioxide are considerably lower, which can be explained by a stronger extraction of perchloric acid

  2. Immunological detection of small organic molecules in the presence of perchlorates: relevance to the life marker chip and life detection on Mars.

    Science.gov (United States)

    Rix, Catherine S; Sims, Mark R; Cullen, David C

    2011-11-01

    The proposed ExoMars mission, due to launch in 2018, aims to look for evidence of extant and extinct life in martian rocks and regolith. Previous attempts to detect organic molecules of biological or abiotic origin on Mars have been unsuccessful, which may be attributable to destruction of these molecules by perchlorate salts during pyrolysis sample extraction techniques. Organic molecules can also be extracted and measured with solvent-based systems. The ExoMars payload includes the Life Marker Chip (LMC) instrument, capable of detecting biomarker molecules of extant and extinct Earth-like life in liquid extracts of martian samples with an antibody microarray assay. The aim of the work reported here was to investigate whether the presence of perchlorate salts, at levels similar to those at the NASA Phoenix landing site, would compromise the LMC extraction and detection method. To test this, we implemented an LMC-representative sample extraction process with an LMC-representative antibody assay and used these to extract and analyze a model sample that consisted of a Mars analog sample matrix (JSC Mars-1) spiked with a representative organic molecular target (pyrene, an example of abiotic meteoritic infall targets) in the presence of perchlorate salts. We found no significant change in immunoassay function when using pyrene standards with added perchlorate salts. When model samples spiked with perchlorate salts were subjected to an LMC-representative liquid extraction, immunoassays functioned in a liquid extract and detected extracted pyrene. For the same model sample matrix without perchlorate salts, we observed anomalous assay signals that coincided with yellow coloration of the extracts. This unexpected observation is being studied further. This initial study indicates that the presence of perchlorate salts, at levels similar to those detected at the NASA Phoenix landing site, is unlikely to prevent the LMC from extracting and detecting organic molecules from

  3. Multi-fractal property of perchlorate reductase gene sequences and DNA photonics application to UV fluorescence detection on Mars-like surfaces

    Science.gov (United States)

    Tremberger, George, Jr.; Cheung, Eric; Gadura, N.; Holden, Todd; Subramaniam, Raji; Sullivan, Regina; Schneider, Pat; Flamholz, Alex; Lieberman, David H.; Cheung, Tak D.

    2009-08-01

    The discovery of perchlorate on Mars raises the possibility of the existence of perchlorate reduction microbes on that planet. The perchlorate reductase gene sequence fractal dimensions of two Dechloromonas species were compared with five other sequences in the microbial dimethyl sulfoxide (DMSO) reductase family. A nucleotide sequence can be expressed as a numerical sequence where each nucleotide is assigned its proton number. The resulting numerical sequence can be investigated for its fractal dimension in terms of evolution and chemical properties for comparative studies. Analysis of the fractal dimensions for the DMSO reductase family supports phylogenetic analyses that show that the perchlorate reductase gene sequences are members of the same family. A sub-family with roughly the same nucleotide length emerges having the property that the gene fractal dimension is negatively correlated with the Shannon di-nucleotide entropy (R2 ~ 0.95, N =5). The gene sequence fractal dimension is found to be positively correlated with the neighbor joining distances reported in a published protein phylogeny tree (R2~ 0.92, N = 5). The multi-fractal property associated with these genes shows that perchlorate reductase has lower dimensionality as compared to the relatively higher dimensionality DNA-break repair genes Rec-A and Rad-A observed in the Dechloromonas aromatica and Deinococcus radiodurans genomes. The studied perchlorate gene sequences show a higher Shannon di-nucleotide entropy (~3.97 bits) relative to Dechloromonas aromatica DNA repair sequences (~3.87 bits Rec-A, ~3.92 bits Rad-A), suggesting that there are fewer constraints on nucleotide variety in the perchorlate sequences . These observations thus allow for the existence of perchlorate reducing microbes on Mars now or in the past. Timeresolved UV fluorescence study near the emission bands of nucleotide sequences could be used for bio-detection on Mars-like surfaces and the results may further constrain the

  4. Reverse calcium affinity purification of Fab with calcium derivatized hydroxyapatite

    OpenAIRE

    Gagnon, Pete; Cheung, Chia-wei; Yazaki, Paul J.

    2009-01-01

    This study introduces the application of calcium-derivatized hydroxyapatite for purification of Fab. Fab binds to native hydroxyapatite but fails to bind to the calcium derivatized form. IgG, Fc, and most other protein contaminants bind to the calcium form. This supports Fab purification by a simple flow-through method that achieves greater than 95% purity from papain digests and mammalian cell culture supernatants. Alternatively, Fab can be concentrated on native hydroxyapatite then eluted s...

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

    OpenAIRE

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

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline...

  6. Size and Shape of Ammonium Perchlorate and their Influence on Properties of Composite Propellant

    Directory of Open Access Journals (Sweden)

    Sunil Jain

    2009-05-01

    Full Text Available Most of the composite propellant compositions contain solid loading up to 86 per cent. The main solid ingredients of composite propellant are ammonium perchlorate (AP and aluminium powder. Therefore, it is a must to characterise these to improve processibility and quality of composite propellant. Effect of particle size on propellants slurry viscosity and ballistic parameters are well documented, however, the effect of oxidizer particle shape is not reported. In the present study, different methods for size and shape characterisation are discussed and effect of size and shape of AP on composite propellant properties are studied. The data indicate that as size of AP decreases, propellant slurry viscosity increases and burn rate increases. The particles having higher shape factor provides less endof mix (EOM viscosity of propellant slurry and burn rate. Further, effect of size of ground AP on shape is also investigated. From the data thus obtained, it is inferred that as size of ground AP decreases, shape factor decreases, and particles become more irregular in shape.Defence Science Journal, 2009, 59(3, pp.294-299, DOI:http://dx.doi.org/10.14429/dsj.59.1523

  7. Structure and properties of 2-cyanopyridinium perchlorate [2-CNPyH][ClO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Czupinski, O [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Wojtas, M [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Zaleski, J [Institute of Chemistry, University of Opole, Oleska 48, 45-951 Opole (Poland); Jakubas, R [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Medycki, W [Institute of Molecular Physics, Polish Academy of Science, Smoluchowskiego 17, 60-179 Poznan (Poland)

    2006-03-29

    The crystal structure of 2-cyanopyridinium perchlorate, [2-CNPyH][ClO{sub 4}], has been determined at 100 (phase II) and 293 K (phase I). It is monoclinic P 2{sub 1} at 100 K and orthorhombic P 2{sub 1}2{sub 1}2{sub 1} at 293 K. The dynamic properties of the crystal were studied by differential scanning calorimetry, dilatometry, pyroelectric, dielectric, proton ({sup 1}H NMR), chlorine ({sup 35}Cl NMR) magnetic resonance spectroscopies and the infrared method. The crystal undergoes a structural phase transition (I {yields}II) at 170K characterized by a complex mechanism involving both 'order-disorder' and 'displacive' contributions. It reveals pyroelectric properties below 170K. The dielectric relaxation existing over phase I is due to the motion of the cyano group, whereas the dynamics of the [ClO{sub 4}]{sup -} anions is reflected in the significant dielectric increment around the I {yields}II phase transition.

  8. Shock wave response of ammonium perchlorate single crystals to 6 GPa

    International Nuclear Information System (INIS)

    Plane shock wave experiments were carried out on ammonium perchlorate single crystals compressed along [210] and [001] orientations to peak stresses ranging from 1.2 to 6.2 GPa. Quartz gauge and velocity interferometer techniques were used to measure the elastic and plastic shock wave velocities, and stress and particle velocity histories in the shocked samples. The measured Hugoniot elastic limit (HEL) was 0.48±0.09 GPa. Above the HEL and up to about 6 GPa, the data show a clear two-wave structure, indicating an elastic-plastic response. Time-dependent elastic precursor decay and plastic wave ramping are discernable and orientation dependent in the low stress data. However, the orientation dependence of the peak state response is small. Hence, data for both orientations were summarized into a single isotropic, elastic-plastic-stress relaxation model. Reasonable agreement was obtained between the numerical simulations using this model and the measured wave profiles. At a shock stress of about 6 GPa and for the time duration and crystal orientations examined, we did not observe any features that may be identified as a sustained chemical reaction or a phase transformation. (c) 2000 American Institute of Physics

  9. Microscopic observations of X-ray and gamma-ray induced decomposition of ammonium perchlorate crystals

    Science.gov (United States)

    Herley, P. J.; Levy, P. W.

    1972-01-01

    The X-ray and gamma-ray induced decomposition of ammonium perchlorate was studied by optical, transmission, and scanning electron microscopy. This material is a commonly used oxidizer in solid propellents which could be employed in deep-space probes, and where they will be subjected to a variety of radiations for as long as ten years. In some respects the radiation-induced damage closely resembles the effects produced by thermal decomposition, but in other respects the results differ markedly. Similar radiation and thermal effects include the following: (1) irregular or ill-defined circular etch pits are formed in both cases; (2) approximately the same size pits are produced; (3) the pit density is similar; (4) the c face is considerably more reactive than the m face; and (5) most importantly, many of the etch pits are aligned in crystallographic directions which are the same for thermal or radiolytic decomposition. Thus, dislocations play an important role in the radiolytic decomposition process.

  10. Spectroscopic and structural studies of di-ureasils doped with lithium perchlorate

    International Nuclear Information System (INIS)

    Di-urea cross-linked POE/siloxane hybrid ormolytes (di-ureasils) doped with a wide concentration range of lithium perchlorate trihydrate (LiClO4.3H2O) (200 ≥ n ≥ 0.5, where n expresses the salt content in terms of the number of ether oxygen atoms per Li+ ion) have been analysed by Fourier transform infrared and Raman (FT-IR and FT-Raman, respectively) spectroscopies and X-ray diffraction (XRD). The results obtained lead us to conclude that the xerogels with n ≥ 5 are totally amorphous. At n ≤ 1 free salt is observed. 'Free' ClO4- ions appear to be the main charge carriers at the conductivity maximum located within the 25 ≤ n ≤ 8 composition range of this family of ormolytes. At n = 15 ClO4- ions coordinated in mono/tridentate (C3v symmetry) and bidentate (C2v symmetry) configurations were detected. In salt-rich samples with n + ions bond to the urea carbonyl oxygen atoms over the entire range of salt concentration studied

  11. Ion Conduction and Polymer Dynamics of Poly(2-vinylpyridine) - Lithium Perchlorate Mixtures

    Science.gov (United States)

    Atorngitjawat, Pornpen; Runt, James

    2008-03-01

    Ion conduction and polymer dynamics of single phase mixtures of poly(2-vinylpyridine) (P2VPy) with 0.1 to 10 mol% lithium perchlorate (LiClO4) were investigated using broadband dielectric spectroscopy. Interpretation of the relaxation behavior was assisted by findings from wide-angle and small-angle X-ray scattering experiments, and other techniques. Five dielectric relaxations were observed: a local β process in the glassy state, a segmental relaxation, a slow segmental process, an ion-mode relaxation, and electrode polarization. The local P2VPy relaxation was strongly suppressed with increasing LiClO4 content arising from the formation of transient crosslinks, which lead to a subsequent decrease in the number of free pyridine groups, and/or a reduction in the local free volume in the presence of LiClO4. Ion conduction at low LiClO4 concentrations (diffusion of anions through the matrix, which is strongly coupled with the segmental relaxation. At relatively high LiClO4 concentration (10 mol%), partial decoupling between ion motion and the segmental relaxation was observed, leading to increased conductivity.

  12. Effect of Surface Microstructure on the Temperature sensitivity of Burning Rate of Ammonium Perchlorate

    Directory of Open Access Journals (Sweden)

    K. Kishore

    1997-04-01

    Full Text Available Considering Vielle's law and the new thermodynamic model which the authors have developed recently the true dependence of temperature sensitivity of burning rate of ammonium perchlorate (AP on pressure is resolved and experimentally verified for bellet burning. The value of decreases with pressure steeply in regime I' (below 20 atm, but gently in regime I (above 20 atm. The value of powder AP has been determined and it is observed that (powder > (pellet, which clearly suggests that of is innuenced by the surface temperature sensitive parameter and hence by the surface/subsurface microstructure. In powder burning, the buoyant lifting of the particles into the gas phase occurs, Which constitutes the so-called 'free board region' (FER extending just above the true surface. Consequent to the decomposition of AP particles in FER, the condensed phase heat release gets curtailed and (powder becomes larger. A general relationship for in terms of density and surface temperature is suggested, which is applicable to both pellet and powder AP.

  13. Stoichiometric analysis of ammonium nitrate and ammonium perchlorate with nanosecond laser induced breakdown spectroscopy

    Science.gov (United States)

    Sreedhar, S.; Rao, S. Venugopal; Kiran, P. Prem; Tewari, Surya P.; Kumar, G. Manoj

    2010-04-01

    We present our results on the stoichiometric analysis of ammonium nitrate (AN) and ammonium Perchlorate (AP) studied using laser induced breakdown spectroscopy (LIBS) with nanosecond pulses. The LIBS spectra collected for AP and AN, without any gating and using a high resolution spectrometer, exhibited characteristic lines corresponding to O, N, H, C, and K. The Oxygen line at 777.38 nm and three Nitrogen lines (N1, N2, N3) at 742.54 nm, 744.64 nm, 747.12 nm were used for evaluating the Oxygen/Nitrogen ratios. The intensities were calculated using area under the peaks and normalized to their respective transition probabilities and statistical weights. The O/N1 ratios estimated from the LIBS spectra were ~4.94 and ~5.11 for AP and O/N3 ratios were ~1.64 and ~1.47 for AN obtained from two independent measurements. The intensity ratios show good agreement with the actual stoichiometric ratios - four for AP and one for AN.

  14. Poly[[μ2-acetato-aquadi-μ3-isonicotinato-holmium(IIIsilver(I] perchlorate

    Directory of Open Access Journals (Sweden)

    Sun Feng

    2009-12-01

    Full Text Available In the title three-dimensional heterometallic complex, {[AgHo(C6H4NO22(C2H3O2(H2O]ClO4}n, the HoIII ion is eight-coordinated by four O atoms from four different isonicotinate ligands, three O atoms from two different acetate ligands and one O atom of a water molecule. The two-coordinate AgI ion is bonded to two N atoms from two different isonicotinate anions. These metal coordination units are connected by bridging isonicotinate and acetate ligands, generating a three-dimensional network. The coordinated water molecules link the carboxylate group of the acetate ligand and the nitrate ligand by O—H...O hydrogen bonding. The crystal structure is further stabilized by hydrogen bonds. The perchlorate ion is disordered over two sites with site-occupancy factors 0.539 (12 and 0.461 (12, while the methyl group of the acetate ligand is disordered over two sites with site-occupancy factors 0.51 (4 and 0.49 (4.

  15. Calcium – how and why?

    Indian Academy of Sciences (India)

    J K Jaiswal

    2001-09-01

    Calcium is among the most commonly used ions, in a multitude of biological functions, so much so that it is impossible to imagine life without calcium. In this article I have attempted to address the question as to how calcium has achieved this status with a brief mention of the history of calcium research in biology. It appears that during the origin and early evolution of life the Ca2+ ion was given a unique opportunity to be used in several biological processes because of its unusual physical and chemical properties.

  16. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Moilanen, A.; Norby, P.; Papadakis, K.; Posselt, D.; Sørensen, L. H.

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...

  17. Calcium Phosphate Biomaterials: An Update

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Current calcium phosphate (CaP) biomaterials for bone repair, substitution, augmentation and regeneration include hydroxyapatite ( HA ) from synthetic or biologic origin, beta-tricalcium phosphate ( β-TCP ) , biphasic calcium phosphate (BCP), and are available as granules, porous blocks, components of composites (CaP/polymer) cements, and as coatings on orthopedic and dental implants. Experimental calcium phosphate biomaterials include CO3- and F-substituted apatites, Mg-and Zn-substituted β-TCP, calcium phosphate glasses. This paper is a brief review of the different types of CaP biomaterials and their properties such as bioactivity, osteoconductivity, osteoinductivity.

  18. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used...

  19. 21 CFR 573.260 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  20. Calcium measurement methods

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2010-09-01

    Full Text Available Rightly stressed by prof. Wolfgang Walz in the Preface to the series Neuromethods series, the “careful application of methods is probably the most important step in the process of scientific inquiry”. Thus, I strongly suggest to all those interested in calcium signaling and especially to the new-comers in the hot topic of neuroscience (which has so much space even in science-society debate for its implications in legal issues and in the judge-decision process to take profit from this so well edited book. I am saying this since prof. Verkhratsky and prof. Petersen......

  1. Extracellular calcium sensing and extracellular calcium signaling

    Science.gov (United States)

    Brown, E. M.; MacLeod, R. J.; O'Malley, B. W. (Principal Investigator)

    2001-01-01

    , localized changes in Ca(o)(2+) within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca(2+). In any event, the CaR and other receptors/sensors for Ca(o)(2+) and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

  2. Compartmentalization of the submembrane calcium activity during calcium influx and its significance in transmitter release.

    OpenAIRE

    Simon, S M; Llinás, R R

    1985-01-01

    Quantitative modeling indicates that, in presynaptic terminals, the intracellular calcium concentration profile during inward calcium current is characterized by discrete peaks of calcium immediately adjacent to the calcium channels. This restriction of intracellular calcium concentration suggests a remarkably well specified intracellular architecture such that calcium, as a second messenger, may regulate particular intracellular domains with a great degree of specificity.

  3. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

    ... Balance › Vitamin D, Calcium, and Bone Health Vitamin D, Calcium, and Bone Health March 2012 Download PDFs ... helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin D ...

  4. Calcium, vitamin D, and your bones

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000490.htm Calcium, vitamin D, and your bones To use the sharing ... and maintain strong bones. How Much Calcium and Vitamin D Do I Need? Amounts of calcium are ...

  5. Calcium transport in turtle bladder

    International Nuclear Information System (INIS)

    Unidirectional 45Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (JnetCa) was secretory (serosa to mucosa). Ouabain reversed JnetCa to an absorptive flux. Amiloride reduced both fluxes such that JnetCa was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, JnetCa decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, JnetCa was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45Ca content was ≅30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca2+-ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na+-K+-ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa

  6. An Improved Calcium Flame Test.

    Science.gov (United States)

    Pearson, Robert S.

    1985-01-01

    Indicates that the true red color of calcium can be obtained (using the procedure described by Sorm and Logowski) if the calcium ion solution is mixed with an equal volume of saturated ammonium bromide solution. Suggestions for flame tests of other elements are also noted. (JN)

  7. Structural characterization, phase transition and dielectric properties of 4-cyanopyridynium perchlorate monohydrate: [(4-CNC 5H 4NH)][ClO 4]·H 2O

    Science.gov (United States)

    Czupiński, O.; Wojtaś, M.; Pietraszko, A.; Jakubas, R.

    2007-01-01

    Crystal structure of 4-cyanopyridynium perchlorate monohydrate ([(4-CNC 5H 4NH)][ClO 4]·H 2O) has been determined at 293 and 240 K as orthorhombic space group, Pnma and monoclinic space group, P2 1/ c, respectively, by means of single crystal X-ray diffraction. At room temperature the perchlorate anion reveals significant disorder, which is realized by the splitting of two oxygen atoms into four sites. DSC, dilatometric and dielectric spectroscopy techniques show that the crystal undergoes phase transition at 286/288 K (on cooling/heating scans). [(4-CNC 5H 4NH)][ClO 4]·H 2O appears to be an insulator with relatively high activation energy of the order of 100 kJ/mol. The phase transition in the title crystal is believed to be related to the dynamics of the perchlorate anion.

  8. Shock sensitivity of the explosive 2-(5-Cyanotetrazolato) Pentaamine Cobalt(III) Perchlorate (CP)

    International Nuclear Information System (INIS)

    The inorganic explosive, 2-(5-Cyanotetrazolato) Pentaamine Cobalt(III) Perchlorate, more commonly designated CP, is used in a number of hot-wire initiated deflagration-to-detonation detonators. Analyses of the safety aspects of these detonators are dependent upon utilizing shock initiation sensitivity data on this explosive where sensitivity is defined as the amplitude (P) and duration (tau) of the shock stimulus which produces a 50% probability of initiation. In this work the shock sensitivity of CP powder pressed to 1.50 Mg/m3 bulk density was determined using flyer plate impact techniques which provided pulse durations of 0.17 μs and 0.23 μs and pulse amplitudes of 0.8 to 2.3 GPa. Impact tests were conducted in air and vacuum, and with flyers of different area. It was necessary to develop a new test technique to generate flyer velocities to bracket the threshold of initiation for this study. This was done by electrically exploding a metal foil against a lucite shock-moderator from which a plastic flyer lifted off at a controlled velocity. The energy source was a large capacitor bank and provided flyer velocities repeatable within 7% and with a planarity of 30 ns or less. The pressure thresholds for detonation of CP were found to be 1.75 GPa and 1.40 GPa, for pulse durations of 0.17 μs and 0.23 μs respectively. There was no discernible difference in response between samples tested in air or vacuum, or with flyers of different area, within experimental error

  9. Widespread presence of naturally occurring perchlorate in high plains of Texas and New Mexico

    Science.gov (United States)

    Rajagopalan, S.; Anderson, T.A.; Fahlquist, L.; Rainwater, K.A.; Ridley, M.; Jackson, W.A.

    2006-01-01

    Perchlorate (ClO4-) occurrence in groundwater has previously been linked to industrial releases and the historic use of Chilean nitrate fertilizers. However, recently a number of occurrences have been identified for which there is no obvious anthropogenic source. Groundwater from an area of 155 000 km2 in 56 counties in northwest Texas and eastern New Mexico is impacted by the presence of ClO4-. Concentrations were generally low (<4 ppb), although some areas are impacted by concentrations up to 200 ppb. ClO4- distribution is not related to well type (public water system, domestic, agricultural, or water-table monitoring) or aquifer (Ogallala, Edward Trinity High Plains, Edwards Trinity Plateau, Seymour, or Cenozoic). Results from vertically nested wells strongly indicate a surface source. The source of ClO4- appears to most likely be atmospheric deposition. Evidence supporting this hypothesis primarily relates to the presence of ClO 4- in tritium-free older water, the lack of relation between land use and concentration distribution, the inability of potential anthropogenic sources to account for the estimated mass of ClO4-, and the positive relationship between conserved anions (e.g., IO3-, Cl-, SO4-2) and ClO4-. The ClO4- distribution appears to be mainly related to evaporative concentration and unsaturated transport. This process has led to higher ClO4- and other ion concentrations in groundwater where the water table is relatively shallow, and in areas with lower saturated thickness. Irrigation may have accelerated this process in some areas by increasing the transport of accumulated salts and by increasing the number of evaporative cycles. Results from this study highlight the potential for ClO4- to impact groundwater in arid and semiarid areas through long-term atmospheric deposition. ?? 2006 American Chemical Society.

  10. Solution-reaction Calorimetric Study of Coordination Compounds of Rare Earth Perchlorates with Alanine and Imidazole

    Institute of Scientific and Technical Information of China (English)

    ZHAO, Yan-Ru(赵艳茹); HOU, An-Xin(侯安新); DONG, Jia-Xin(董家新); ZHAO, Shun-Sheng(赵顺省); LIU, Yi(刘义); QU, Song-Sheng(屈松生)

    2004-01-01

    Two coordination compounds of rare earth perchlorates with alanine and imidazole, [RE(Ala)n(Im)(H2O)](ClO4)3(s) (RE=La, n=3; RE=Nd, n=2), have been prepared and characterized. The standard molar enthalpies of reaction for the following two reactions, LaCL·7H2O(s)+3Ala(s)+Im(s)+3NaClO4(s)=[La(Ala).(Im)(H2O)]-(ClO4)3(s)+3NaCl(s)+6H2O(I)(1)and NdCl3·6H2O(s)+2Ala(s)+2Ala(s)+Im(s)+3NaClO4(s)=[Nd(Ala)2(Im)(H2O)]-(ClO4)3(s)+3NaCl(s)+5H2O(l) (2), were determined by solution-reaction calorimetry, at T=298.15 K, as 36.168 ±0.642kJ·mol-1 and 48.590±0.934kJ·mol-1 respectively. From the results and other auxiliary quantities, the standard molar enthalpies of formation of [La(Ala)3(Im)(H2O)](ClO4)3(s) and [Nd(Ala)2(Im)(H2O)] (ClO4)3(s) were derived,△fH(-)m{[La(Ala).(Im)(H2O)](ClO4)3,s}=(-2984.8±1.0)kJ·mol-1 and △fH(-)m{[Nd(Ala).(Im)(H2O)]-(ClO4)3,s}=(-2387.8±0.8)kJ·mol-1, respectively.

  11. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    OpenAIRE

    Choksi Krishna; Shenoy Ashoka M; A. R. Shabharaya; Lala Minaxi

    2011-01-01

    The objective of present study is to evaluate the effects of calcium carbonate and calcium gluconate on acute and subacute inflammation and to study their possible interactions with Aspirin. Calcium carbonate (10 mg/kg) and calcium gluconate (5 mg/kg) were administered individually and also co-administered along with sub therapeutic dose Aspirin (50mg/kg) to study their interaction. The inflammation was induced by carrageenan or a foreign body. Both calcium carbonate and calcium gluconate cou...

  12. 4,4,5,5-Tetramethyl-2-(4-pyridinio-2-imidazoline-1-oxyl-3-oxide perchlorate

    Directory of Open Access Journals (Sweden)

    Kai Jiang

    2009-05-01

    Full Text Available The crystal structure of the title compound, C12H17N3O2+·ClO4−, consists of 4,4,5,5-tetramethyl-2-(4-pyridinioimidazoline-1-oxyl-3-oxide radical cations and perchlorate anions. Both the cation and the Cl atom of the anion are located on the same twofold rotation axis, and the crystal structure shows the average structure for the radical cation. The five-membered ring assumes a half-chair conformation. The cation links with the anion via N—H...O hydrogen bonding.

  13. Kinetics and mechanism of oxidation of glycine by iron(III)-1,10-phenanthroline complex in perchloric acid medium

    Indian Academy of Sciences (India)

    T V N Partha Sarathi; A Kalyan Kumar; K Krishna Kishore; P Vani

    2005-07-01

    Kinetics and mechanism of oxidation of glycine by iron(III)-1,10-phenanthroline complex has been studied in perchloric acid medium. The reaction is first order with respect to iron(III) and glycine. An increase in (phenanthroline) increases the rate, while increase in [H+] decreases the rate. Hence it can be inferred that the reactive species of the substrate is the zwitterionic form and that of the oxidant is [Fe(phen)2(H2O)2]3+. The proposed mechanism leads to the rate law as elucidated.

  14. Eu(III) extraction by bis(2-ethylhexyl)phosphoric acid and 8-hydroxyquinoline in dodecane from perchlorate medium

    International Nuclear Information System (INIS)

    Europium(III) was extracted by bis(2-ethylhexyl)phosphoric acid (HDEHP) and 8-hydroxyquinoline (HQ) in dodecane from aqueous perchlorate media of constant ionic strength (0.1M; H+, NaClO4). Slope analysis of the data indicate that three molecules of HDEHP or HQ are attached to Eu3+. Extraction constants were obtained at different temperatures. The data were used to calculate the thermodynamic parameters (ΔG, ΔH and ΔS) for the extraction process in the two systems. When using mixtures of crown ethers with HDEHP no synergism was observed. (author) 18 refs.; 8 figs.; 3 tabs

  15. Thermodynamics of Eu(III) extraction by Bis (2-ethylhexyl) phosphoric acid or 8-hydroxyquinoline in dodecane from perchlorate medium

    International Nuclear Information System (INIS)

    Europium (III) was extracted by bis (2-ethylhexyl) phosphoric acid (HDEHP) and 8-hydroxyquinoline (Hq) at different temperatures in dodecane, from perchlorate aqueous media of constant ionic strength (0.1 M ; H+, NaCl O4). Slope analysis of the data indicated that three molecules of HDEHP or Hq are attached to Eu3+. The extraction constants were evaluated at different temperatures. The data obtained were used to calculate the thermodynamic parameters (Δ G,Δ H and Δ S ) for the two systems. Some trials to use mixtures of crown ethers with the reagents investigated but no synergism was observed. 8 fig.,3 tab

  16. (Per)chlorate reduction by the thermophilic bacterium Moorella perchloratireducens sp. nov., isolated from underground gas storage

    OpenAIRE

    Balk, M.; Gelder, van, M.; Weelink, S.A.B.; Stams, A.J.M.

    2008-01-01

    A thermophilic bacterium, strain An10, was isolated from underground gas storage with methanol as a substrate and perchlorate as an electron acceptor. Cells were gram-positive straight rods, 0.4 to 0.6 µm in diameter and 2 to 8 µm in length, growing as single cells or in pairs. Spores were terminal with a bulged sporangium. The temperature range for growth was 40 to 70°C, with an optimum at 55 to 60°C. The pH optimum was around 7. The salinity range for growth was between 0 and 40 g NaCl lite...

  17. (Per)chlorate Reduction by the Thermophilic Bacterium Moorella perchloratireducens sp. nov., Isolated from Underground Gas Storage▿

    OpenAIRE

    2007-01-01

    A thermophilic bacterium, strain An10, was isolated from underground gas storage with methanol as a substrate and perchlorate as an electron acceptor. Cells were gram-positive straight rods, 0.4 to 0.6 μm in diameter and 2 to 8 μm in length, growing as single cells or in pairs. Spores were terminal with a bulged sporangium. The temperature range for growth was 40 to 70°C, with an optimum at 55 to 60°C. The pH optimum was around 7. The salinity range for growth was between 0 and 40 g NaCl lite...

  18. Preignition reactions of AP-HTPB propellants studied by IR spectrometry. [Ammonium Perchlorate-Hydroxyl Terminated PolyButadiene

    Science.gov (United States)

    Law, R. J.; Baer, A. D.; Ryan, N. W.

    1977-01-01

    IR absorption spectrometry was used to follow the disappearance of NH and CH bonds during the pyrolysis of a polymer film containing 30 weight percent ammonium perchlorate (AP). The remaining 70 weight percent consisted of a mixture of 92.5 weight percent hydroxyl-terminated polybutadiene (HTPB) and 7.5 weight percent isophrone diisocyanate (IPDI). The results indicate that polymer decomposition is induced by products of AP decomposition, and that about 2.5 CH bonds disappear for each NH bond that disappears. The diffusion process occurring in the later stages of the reaction is analyzed in an attempt to account for the unexpectedly low activation energy.

  19. On the adhesion between hydroxyl-terminated polybutadiene fuel-binder and ammonium perchlorate. Performance of bonding agents

    Energy Technology Data Exchange (ETDEWEB)

    Hori, K.; Iwama, A.; Fukuda, T.

    1985-12-01

    A simple method to evaluate the adhesive force between solid oxidizer and polymeric fuel-binder is presented. As an illustration, hydroxyl-terminated polybutadiene (HTPB) sticks including several different bonding agents are bonded on ammonium perchlorate (AP) single crystals, and stress-strain history unitl rupture occurs is obtained by applying uniaxial tensile stress perpendicularly to the adhesion surface. Further, whether each bonding agent reacts with AP or not was analysed with pursuing infrared absorption spectra. The hypothesis that the interfacial adhesive force arises from hydrogen bonding force is proposed.

  20. Analysis of perchlorate in foods and beverages by ion chromatography coupled with tandem mass spectrometry (IC-ESI-MS/MS)

    International Nuclear Information System (INIS)

    A new IC-ESI-MS/MS method, with simple sample preparation procedure, has been developed for quantification and confirmation of perchlorate (ClO4-) anions in water, fresh and canned food, wine and beer samples at low part-per-trillion (ng l-1) levels. To the best of our knowledge, this is the first time an analytical method is used for determination of perchlorate in wine and beer samples. The IC-ESI-MS/MS instrumentation consisted of an ICS-2500 ion chromatography (IC) system coupled to either an API 2000TM or an API 3200TM mass spectrometer. The IC-ESI-MS/MS system was optimized to monitor two pairs of precursor and fragment ion transitions, i.e., multiple reaction monitoring (MRM). All samples had oxygen-18 isotope labeled perchlorate internal standard (ISTD) added prior to extraction. Chlorine isotope ratio (35Cl/37Cl) was used as a confirmation tool. The transition of 35Cl16O4- (m/z 98.9) into 35Cl16O3- (m/z 82.9) was monitored for quantifying the main analyte; the transition of 37Cl16O4- (m/z 100.9) into 37Cl16O3- (m/z 84.9) was monitored for examining a proper isotopic abundance ratio of 35Cl/37Cl; and the transition of 35Cl18O4- (m/z 107.0) into 35Cl18O3- (m/z 89.0) was monitored for quantifying the internal standard. The minimum detection limit (MDL) for this method in de-ionized water is 5 ng l-1 (ppt) using the API 2000TM mass spectrometer and 0.5 ng l-1 using the API 3200TM mass spectrometer. Over 350 food and beverage samples were analyzed mostly in triplicate. Except for four, all samples were found to contain measurable amounts of perchlorate. The levels found ranged from 5 ng l-1 to 463.5 ± 6.36 μg kg-1 using MRM 98.9 → 82.9 and 100 μl injection

  1. cis-Aquabis(2,2′-bipyridine-κ2N,N′fluoridochromium(III bis(perchlorate dihydrate

    Directory of Open Access Journals (Sweden)

    Torben Birk

    2010-02-01

    Full Text Available The title mixed aqua–fluoride complex, [CrF(C10H8N22(H2O](ClO42·2H2O, has been synthesized by aquation of the corresponding difluoride complex using lanthanide(III ions as F− acceptors. The complex crystallizes with a CrIII ion at the center of a distorted octahedral coordination polyhedron with a cis arrangement of ligands. The crystal packing shows a hydrogen-bonding pattern involving water molecules, the coordinated F atom and the perchlorate anions

  2. High-nitrogen-based pyrotechnics: longer- and brighter-burning, perchlorate-free, red-light illuminants for military and civilian applications.

    Science.gov (United States)

    Sabatini, Jesse J; Nagori, Amita V; Chen, Gary; Chu, Phillip; Damavarapu, Reddy; Klapötke, Thomas M

    2012-01-01

    The full-up prototype testing of perchlorate-free, hand-held, signal illuminants for the US Army's M126A1 red star parachute hand-held signal is described. Compared to the perchlorate-containing control, the disclosed illuminants yielded excellent stabilities toward various ignition stimuli while offering superior pyrotechnic performance. Militarily, the illuminants provided further evidence that development of smaller hand-held signal items in an environmentally conscious way is a realistic and obtainable goal. The results are also important from the perspective of civilian fireworks, as the development of brighter, longer-burning, and environmentally compatible red-light-emitting pyrotechnics is now possible. PMID:22161957

  3. A Hydrogen Ion-Selective Poly(Vinyl Chloride) Membrane Electrode Based on Calix[4]arene as a Perchlorate Ion-Selective Electrode

    OpenAIRE

    CANEL, Esin; ERDEN, Sevcan; ÖZEL, Ayça DEMİREL; MEMON, Sahahabuddin

    2008-01-01

    A hydrogen ion-selective electrode was prepared using 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetracyanometoxy-calix[4]arene and the possibility of its use as a perchlorate ion-selective electrode was investigated using its characteristic of becoming perchlorate sensitive in acidic regions. The electrode of the optimum characteristic had a composition of 1% ionophore, 66% o-NPOE, and 33% PVC. This electrode exhibited a linear response over the range 1.0 \\times 10-1-1.0 \\times 10-5 M o...

  4. Limestone reaction in calcium aluminate cement–calcium sulfate systems

    International Nuclear Information System (INIS)

    This paper reports a study of ternary blends composed of calcium aluminate cement, calcium sulfate hemihydrate and limestone. Compressive strength tests and hydration kinetics were studied as a function of limestone and calcium sulfate content. The phase evolution and the total porosity were followed and compared to thermodynamic simulation to understand the reactions involved and the effect of limestone on these binders. The reaction of limestone leads to the formation of hemicarboaluminate and monocarboaluminate. Increasing the ratio between sulfate and aluminate decreases the extent of limestone reaction

  5. Calcium binding protein-mediated regulation of voltage-gated calcium channels linked to human diseases

    Institute of Scientific and Technical Information of China (English)

    Nasrin NFJATBAKHSH; Zhong-ping FENG

    2011-01-01

    Calcium ion entry through voltage-gated calcium channels is essential for cellular signalling in a wide variety of cells and multiple physiological processes. Perturbations of voltage-gated calcium channel function can lead to pathophysiological consequences. Calcium binding proteins serve as calcium sensors and regulate the calcium channel properties via feedback mechanisms. This review highlights the current evidences of calcium binding protein-mediated channel regulation in human diseases.

  6. A novel hydrolysis method to synthesize chromium hydroxide nanoparticles and its catalytic effect in the thermal decomposition of ammonium perchlorate

    International Nuclear Information System (INIS)

    Highlights: ► Synthesis of Cr(OH)3 nanoparticles in Cr3+–F− aqueous solution. ► The F− ion tailors coagulated materials, Cr(OH)3 nanoparticles are obtained. ► Adding nanosized Cr(OH)3, AP thermal decomposition temperature decreases to 200 °C. ► The nanosized Cr(OH)3 catalyzes NH3 oxidation, accelerating AP thermal decomposition. - Abstract: A procedure for the preparation of spherical Cr(OH)3 nanoparticles was developed based on the aging of chromium nitrate aqueous solutions in the presence of sodium fluoride, urea, and polyvinylpyrrolidone. Using scanning electron microscopy, transmission electron microscopy, and energy dispersive spectroscopy, the morphological characteristics of Cr(OH)3 were controlled by altering the molar ratio of fluoride ion to chromium ion, as well as the initial pH and chromium ion concentration. The prepared nanosized Cr(OH)3 decreased the temperature required to decompose ammonium perchlorate from 450 °C to about 250 °C as the catalyst. The possible catalytic mechanism of the thermal decomposition of ammonium perchlorate was also discussed.

  7. Study of the ion-channel behavior on glassy carbon electrode supported bilayer lipid membranes stimulated by perchlorate anion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiquan; Shi, Jun; Huang, Weimin, E-mail: huangwm@jlu.edu.cn

    2015-10-01

    In this paper, a kind of didodecyldimethylammonium bromide (DDAB) layer membranes was supported on a glassy carbon electrode (GCE). We studied the ion channel behavior of the supported bilayer lipid membrane by scanning electrochemical microscopy (SCEM) in tris(2,2′-bipyridine) ruthenium(II) solution. Perchlorate anion was used as a presence of stimulus and ruthenium(II) complex cations as the probing ions for the measurement of SECM, the lipid membrane channel was opened and exhibited the behavior of distinct SECM positive feedback curve. The channel was in a closed state in the absence of perchlorate anions while reflected the behavior of SECM negative feedback curve. The rates of electron transfer reaction in the lipid membranes surface were detected and it was dependant on the potential of SECM. - Highlights: • The rates of electron transfer reaction in the lipid membranes surface were detected. • Dynamic investigations of ion-channel behavior of supported bilayer lipid membranes by scanning electrochemical microscopy • A novel way to explore the interaction between molecules and supported bilayer lipid membranes.

  8. Study of the ion-channel behavior on glassy carbon electrode supported bilayer lipid membranes stimulated by perchlorate anion

    International Nuclear Information System (INIS)

    In this paper, a kind of didodecyldimethylammonium bromide (DDAB) layer membranes was supported on a glassy carbon electrode (GCE). We studied the ion channel behavior of the supported bilayer lipid membrane by scanning electrochemical microscopy (SCEM) in tris(2,2′-bipyridine) ruthenium(II) solution. Perchlorate anion was used as a presence of stimulus and ruthenium(II) complex cations as the probing ions for the measurement of SECM, the lipid membrane channel was opened and exhibited the behavior of distinct SECM positive feedback curve. The channel was in a closed state in the absence of perchlorate anions while reflected the behavior of SECM negative feedback curve. The rates of electron transfer reaction in the lipid membranes surface were detected and it was dependant on the potential of SECM. - Highlights: • The rates of electron transfer reaction in the lipid membranes surface were detected. • Dynamic investigations of ion-channel behavior of supported bilayer lipid membranes by scanning electrochemical microscopy • A novel way to explore the interaction between molecules and supported bilayer lipid membranes

  9. Calcium carbonate and calcium sulfate in Martian meteorite EETA79001

    Science.gov (United States)

    Gooding, J. L.; Wentworth, S. J.

    1987-01-01

    Chips of glassy Lithology C of EETA79001 were studied by scanning electron microscopy and energy dispersive X-ray spectroscopy to determine the mineralogy and petrogenesis of the glass that was shown by others to contain trapped Mars-like gases. Calcium carbonite was identified as massive to acicular crystals for which Ca, C, and O were the major elements. Calcium sulfate was identified as prismatic-acicular crystals with Ca and S as the major elements.

  10. Selective Anion Exchange Resins for the Removal of Perchlorate [(CIO{sub 4}{sup -})] from Groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Gu, B.

    1999-05-20

    The primary objective of this project was to evaluate a novel bifunctional anion exchange resin for the cost-effective, in situ treatment of groundwater contaminated with perchlorate (ClO{sub 4}{sup -}). Both laboratory and field studies were performed to determine the selectivity and capacity of the bifunctional synthetic resins to sorb ClO{sub 4}{sup -} from simulated or actual contaminated groundwater. A number of synthetic bifunctional resins, including two commercial versions made by Purolite International and three commercially available, mono-functional resins, were tested. Initial laboratory batch and column breakthrough studies determined the best synthetic resins and the optimal conditions for the field experiment. Laboratory results indicated that the bifunctional synthetic resins, D-3696 and RO-02-119 were highly selective toward ClO{sub 4}{sup -} and performed {approx}5 times better than the best commercial nitrate resin (Purolite{reg_sign} A-520E) and more than an order of magnitude better than some nonselective commercial resins (e.g. Amberlite{reg_sign} IRA-900). The bifunctional resins were particularly effective in removing trace quantities of ClO{sub 4}{sup -} in groundwater to below the detection limit ({approx} 3 {micro}g/L). A field trial demonstrated that the bifunctional resin (D-3696) was able to treat {approx} 110,000 bed volumes of groundwater before a 10% breakthrough of ClO{sub 4}{sup -} occurred under the column flow-through conditions (running at {approx} 2 bed volumes per minute). On the other hand, the Purolite{reg_sign} A-520E resin was able to treat {approx} 23,000 bed volumes of groundwater under the same experimental conditions. No pretreatment was needed to remove either dissolved organic matter or other competing anions (such as SO{sub 4}{sup 2-} or NO{sub 3}{sup -}) in the groundwater, and the treatment process did not alter the water quality by removing or adding secondary by-products because of the high selectivity of the

  11. Soil, plant, and terrain effects on natural perchlorate distribution in a desert landscape

    Science.gov (United States)

    Andraski, Brian J.; Jackson, W.A.; Welborn, Toby L.; Böhlke, John Karl; Sevanthi, Ritesh; Stonestrom, David A.

    2014-01-01

    Perchlorate (ClO4−) is a contaminant that occurs naturally throughout the world, but little is known about its distribution and interactions in terrestrial ecosystems. The objectives of this Amargosa Desert, Nevada study were to determine (i) the local-scale distribution of shallow-soil (0–30 cm) ClO4− with respect to shrub proximity (far and near) in three geomorphic settings (shoulder slope, footslope, and valley floor); (ii) the importance of soil, plant, and terrain variables on the hillslope-distribution of shallow-soil and creosote bush [Larrea tridentata (Sessé & Moc. ex DC.) Coville] ClO4−; and (iii) atmospheric (wet plus dry, including dust) deposition of ClO4− in relation to soil and plant reservoirs and cycling. Soil ClO4− ranged from 0.3 to 5.0 μg kg−1. Within settings, valley floor ClO4− was 17× less near shrubs due in part to enhanced leaching, whereas shoulder and footslope values were ∼2× greater near shrubs. Hillslope regression models (soil, R2 = 0.42; leaf, R2 = 0.74) identified topographic and soil effects on ClO4− deposition, transport, and cycling. Selective plant uptake, bioaccumulation, and soil enrichment were evidenced by leaf ClO4− concentrations and Cl−/ClO4− molar ratios that were ∼8000× greater and 40× less, respectively, than soil values. Atmospheric deposition ClO4− flux was 343 mg ha−1 yr−1, ∼10× that for published southwestern wet-deposition fluxes. Creosote bush canopy ClO4− (1310 mg ha−1) was identified as a previously unrecognized but important and active reservoir. Nitrate δ18O analyses of atmospheric deposition and soil supported the leaf-cycled–ClO4− input hypothesis. This study provides basic data on ClO4− distribution and cycling that are pertinent to the assessment of environmental impacts in desert ecosystems and broadly transferable to anthropogenically contaminated systems.

  12. Experimental evidence for supercooled brines, viscous liquids, and low temperature perchlorate glasses on Mars

    Science.gov (United States)

    Toner, J.; Catling, D. C.; Light, B.

    2013-12-01

    The presence of liquid water on the cold and dry surface of Mars is possible where concentrated salt solutions lower the freezing point of water. The eutectic temperature is the maximum equilibrium freezing point depression possible for a given salt solution, which ranges from near 0°C for carbonates and sulfates, to as low as -75°C for perchlorates. Although eutectic temperatures suggest a lower temperature limit for liquid water on Mars, salt solutions will typically supercool below their eutectic before crystallization occurs. We report on results investigating the magnitude of supercooling and its variation with salt composition and concentration for pure salt solutions and saturated soil solutions of MgSO4, MgCl2, NaCl, NaClO4, Mg(ClO4)2, and Ca(ClO4)2. We measured supercooling by monitoring solution temperatures during slow cooling and warming experiments. Our results indicate that supercooling is pervasive. Slowly cooled MgSO4, MgCl2, NaCl, and NaClO4 solutions typically supercool 5-15°C below their eutectic temperature before crystallizing. The addition of soil to these salt solutions has a variable effect on supercooling. Relative to the pure salt solutions, supercooling decreases in MgSO4 soil solutions, increases in MgCl2 soil solutions, and is similar in NaCl and NaClO4 soil solutions. Supercooling in MgSO4, MgCl2, NaCl, and NaClO4 solutions could marginally extend the duration of liquid water during relatively warm daytime temperatures in the Martian summer. Remarkably, we found that Mg(ClO4)2 and Ca(ClO4)2 solutions never crystallize during slow cooling, but remain in a supercooled, liquid state until forming an amorphous glass near -120°C. Even if soil is added to the solutions, which will induce crystallization in most salt solutions, a glass still forms during cooling. The large supercooling effect in Mg(ClO4)2 and Ca(ClO4)2 solutions has the potential to prevent water from freezing over diurnal and possibly annual cycles on Mars. Glasses are

  13. Use of starch and potato peel waste for perchlorate bioreduction in water.

    Science.gov (United States)

    Okeke, Benedict C; Frankenberger, William T

    2005-07-15

    The cost of carbon substrates for microbial reduction of perchlorate (ClO(4)(-)) is central to the success and competitiveness of a sustainable bioremediation strategy for ClO(4)(-). This study explored the potential application of starch in combination with an amylolytic bacterial consortia and potato peel waste for ClO(4)(-) bioreduction. We obtained a potent amylolytic bacterial consortium that consisted of a Citrobacter sp. S4, Streptomyces sp. S2, Flavobacterium sp. S6, Pseudoxanthomonas sp. S5, Streptomyces sp. S7, and an Aeromonas sp. S8 identified by 16S rDNA sequencing. ClO(4)(-) concentration substantially decreased in purified starch medium inoculated with the amylolytic bacterial consortium and Dechlorosoma sp. perclace. Potato peel waste supported ClO(4)(-) reduction by perclace with the rate of ClO(4)(-) reduction being dependent on the amount of potato peels. Over 90% ClO(4)(-) removal was achieved in 4 days in a single time point experiment with 2% (w/v) potato peels waste. ClO(4)(-) reduction in a non-sterile 0.5% potato peel media inoculated with perclace occurred with an initial concentration of 10.14+/-0.04 mg L(-1) to 2.87+/-0.4 mg L(-1) (71.7% reduction) within 5 days. ClO(4)(-) was not detected in the cultures in 6 days. In a non-sterile 0.5% potato media without perclace, ClO(4)(-) depletion occurred slowly from an initial value of 9.99+/-0.15 mg L(-1) to 6.33+/-0.43 mg L(-1) (36.63% reduction) in 5 days. Thereafter, ClO(4)(-) was rapidly degraded achieving 77.1% reduction in 7 days and not detected in 9 days. No susbstantial reduction of ClO(4)(-) was observed in the sterile potato peel media without perclace in 7 days. Redox potential of the potato peel cultures was favorable for ClO(4)(-) reduction, decreasing to as low as -294 mV in 24 h. Sugar levels remained very low in cultures effectively reducing ClO(4)(-) and was substantially higher in sterilized controls. Our results indicate that potato peel waste in combination with amylolytic

  14. Perchlorate in pleistocene and holocene groundwater in North-Central New Mexico

    Science.gov (United States)

    Plummer, L.N.; Böhlke, J.K.; Doughten, M.W.

    2006-01-01

    Groundwater from remote parts of the Middle Rio Grande Basin in north-central New Mexico has perchlorate (ClO4-) concentrations of 0.12-1.8 ??g/L Because the water samples are mostly preanthropogenic in age (0-28 000 years) and there are no industrial sources in the study area, a natural source of the ClO4- is likely. Most of the samples have Br-, Cl-, and SO42- concentrations that are similar to those of modern bulk atmospheric deposition with evapotranspiration (ET) factors of about 7-40. Most of the ET values for Pleistocene recharge were nearly twice that for Holocene recharge. The NO3-/Cl- and ClO4-/Cl- ratios are more variable than those of Br -/Cl- or SO42-/Cl-. Samples thought to have recharged under the most arid conditions in the Holocene have relatively high NO3-/Cl- ratios and low ??15N values (+1 per mil (???)) similar to those of modern bulk atmospheric N deposition. The ??18O values of the NO 3- (-4 to 0 ???) indicate that atmospheric N0 3- was not transmitted directly to the groundwater but may have been cycled in the soils before infiltrating. Samples with nearly atmospheric NO3-/Cl- ratios have relatively high ClO4- concentrations (1.0-1.8 ??g/L) with a nearly constant ClO4-/Cl- mole ratio of (1.4 ?? 0.1) ?? 10-4, which would be consistent with an average ClO 4- concentration of 0.093 ?? 0.005 ??g/L in bulk atmospheric deposition during the late Holocene in north-central NM. Samples thought to have recharged underwetter conditions have higher ??15N values (+3 to +8 ???), lower N03-/Cl- ratios, and lower ClO4-/Cl- ratios than the ones most likely to preserve an atmospheric signal. Processes in the soils that may have depleted atmospherically derived NO3- also may have depleted ClO4- to varying degrees prior to recharge. If these interpretations are correct, then ClO4- concentrations of atmospheric origin as high as 4 ??g/L are possible in preanthropogenic groundwater in parts of the Southwest where ET approaches a factor of 40. Higher ClO4

  15. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes

    OpenAIRE

    Samigullin, Dmitry; Fatikhov, Nijaz; Khaziev, Eduard; Skorinkin, Andrey; Nikolsky, Eugeny; Bukharaeva, Ellya

    2015-01-01

    At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers—which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal—has hitherto been technically impossible. With the aim of quantifying both Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dy...

  16. Variability of calcium absorption

    International Nuclear Information System (INIS)

    Variability in calcium absorption was estimated in three groups of normal subjects in whom Ca absorption was measured by standard isotopic-tracer methods at interstudy intervals ranging from 1 to 4 mo. Fifty absorption tests were performed in 22 subjects. Each was done in the morning after an overnight fast with an identical standard breakfast containing a Ca load of approximately 250 mg. Individual fractional absorption values were normalized to permit pooling of the data. The coefficient of variation (CVs) for absorption for the three groups ranged from 10.57 to 12.79% with the size of the CV increasing with interstudy duration. One other published study presenting replicate absorption values was analyzed in a similar fashion and was found to have a CV of absorption of 9.78%. From these data we estimate that when the standard double-isotope method is used to measure Ca absorption there is approximately 10% variability around any given absorption value within an individual human subject and that roughly two-thirds of this represents real biological variability in absorption

  17. Inhibition of the Sodium-Iodide Symporter by Perchlorate: An Evaluation of Lifestage Sensitivity Using Physiologically Based Pharmacokinetic (PBPK) Modeling (Final Report)

    Science.gov (United States)

    EPA originally released this document in draft form as supporting material for the Preliminary Regulatory Determination on Perchlorate (FR Notice) in October 2008. The document has since been revised in response to comments from independent external peer review. A copy of the PBP...

  18. INHIBITION OF THE SODIUM-IODIDE SYMPORTER BY PERCHLORATE: AN EVALUATION OF LIFESTAGE SENSITIVITY USING PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODELING (EXTERNAL REVIEW DRAFT)

    Science.gov (United States)

    EPA first released this document in draft form as supporting material for the Preliminary Regulatory Determination on Perchlorate (FR Notice) in October 2008. The document has since been revised. The final report is available in response to comments from independent external pee...

  19. Comparison of Pumped and Diffusion Sampling Methods to Monitor Concentrations of Perchlorate and Explosive Compounds in Ground Water, Camp Edwards, Cape Cod, Massachusetts, 2004-05

    Science.gov (United States)

    LeBlanc, Denis R.; Vroblesky, Don A.

    2008-01-01

    Laboratory and field tests were conducted at Camp Edwards on the Massachusetts Military Reservation on Cape Cod to examine the utility of passive diffusion sampling for long-term monitoring of concentrations of perchlorate and explosive compounds in ground water. The diffusion samplers were constructed of 1-inch-diameter rigid, porous polyethylene tubing. The results of laboratory tests in which diffusion samplers were submerged in containers filled with ground water containing perchlorate, RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) indicate that concentrations inside the diffusion samplers equilibrated with concentrations in the containers within the 19-day-long test period. Field tests of the diffusion samplers were conducted in 15 wells constructed of 2- or 2.5-inch-diameter polyvinyl chloride pipe with 10-foot-long slotted screens. Concentrations of perchlorate, RDX, and HMX in the diffusion samplers placed in the wells for 42 to 52 days were compared to concentrations in samples collected by low-flow pumped sampling from 53 days before to 109 days after retrieval of the diffusion samples. The results of the field tests indicate generally good agreement between the pumped and diffusion samples for concentrations of perchlorate, RDX, and HMX. The concentration differences indicate no systematic bias related to contaminant type or concentration levels.

  20. Calcium-sensitive immunoaffinity chromatography

    DEFF Research Database (Denmark)

    Henriksen, Maiken L; Lindhardt Madsen, Kirstine; Skjoedt, Karsten;

    2014-01-01

    homogeneity may be impossible due to contamination with abundant antigens. In this study, we purified the scarce, complement-associated plasma protein complex, collectin LK (CL-LK, complex of collectin liver 1 and kidney 1), by immunoaffinity chromatography using a calcium-sensitive anti-collectin-kidney-1 m......Ab. This antibody was characterized by binding to CL-LK at hypo- and physiological calcium concentrations and dissociated from CK-LK at hyperphysiological concentrations of calcium. We purified CL-LK from plasma to a purity of 41% and a yield of 38%, resulting in a purification factor of more than 88......,000 in a single step. To evaluate the efficiency of this new purification scheme, we purified CL-LK using the same calcium-sensitive mAb in combination with acidic elution buffer and by using calcium-dependent anti-CL-K1 mAbs in combination with EDTA elution buffer. We found that calcium...

  1. Theoretical Study of Energetic Complexes (Ⅲ): Bis-(5-nitro-2Htetrazolato-N2)tetraammine Cobalt(Ⅲ) Perchlorate (BNCP) and Its Transition Metal (Ni/Fe/Cu/Zn) Perchlorate Analogues

    Institute of Scientific and Technical Information of China (English)

    尚静; 张建国; 张同来; 黄辉胜; 张绍文; 舒远杰

    2012-01-01

    The geometric conformation and electronic structure of bis-(5-nitro-2H-tetrazolato-N2)tetraammine cobalt(Ⅲ) perchlorate and its Ni/Fe/Cu/Zn analogues are studied under the TPSS (Tao-Perdew-Staroverov-Scuseria) levels of density functional theory in order to throw light on the relationship between their energy gaps and impact sensitivity While the perchlorate ions are coordinated with the copper cation, which is different from the other four compounds NBO (Natural bond orbital) analyses indicated that the metal-ligand interaction in the Co complex is covalent, while the others are ionic. The analysis of the electrostatic potential demonstrated that the O atoms from the nitro-tetrazole ring and perchlorate were primarily negative, while the other atoms were positive. The study was also conducted to gain a better understanding of the correlation of the energy gap and impact sensitivity.

  2. "Caged calcium" in Aplysia pacemaker neurons. Characterization of calcium-activated potassium and nonspecific cation currents

    OpenAIRE

    1989-01-01

    We have studied calcium-activated potassium current, IK(Ca), and calcium-activated nonspecific cation current, INS(Ca), in Aplysia bursting pacemaker neurons, using photolysis of a calcium chelator (nitr-5 or nitr-7) to release "caged calcium" intracellularly. A computer model of nitr photolysis, multiple buffer equilibration, and active calcium extrusion was developed to predict volume-average and front-surface calcium concentration transients. Changes in arsenazo III absorbance were used to...

  3. Effect of Preharvest Calcium Treatments on Sweet Cherry Fruit Quality

    OpenAIRE

    Deniz EROGUL

    2014-01-01

    In this study, the effects of different foliar calcium compounds on fruit cracking and quality of sweet cherry variety ‘0900 Ziraat’ were investigated. Calcium caseinate, calcium chloride, calcium hydroxide and calcium nitrate were used as foliar sprays. Calcium applications reduced the cracking index 38% to 66% compared to cherries that did not receive foliar treatment. The most efficient applications for decreasing cracking were calcium hydroxide and calcium chloride. Calcium chloride and c...

  4. Stochastic Simulation of Cardiac Ventricular Myocyte Calcium Dynamics and Waves

    OpenAIRE

    Tuan, Hoang-Trong Minh; Williams, George S.B.; Chikando, Aristide C.; Sobie, Eric A.; Lederer, W. Jonathan; Jafri, M. Saleet

    2011-01-01

    A three dimensional model of calcium dynamics in the rat ventricular myocyte was developed to study the mechanism of calcium homeostasis and pathological calcium dynamics during calcium overload. The model contains 20,000 calcium release units (CRUs) each containing 49 ryanodine receptors. The model simulates calcium sparks with a realistic spontaneous calcium spark rate. It suggests that in addition to the calcium spark-based leak, there is an invisible calcium leak caused by the stochastic ...

  5. Aging and calcium as an environmental factor.

    Science.gov (United States)

    Fujita, T

    1985-12-01

    Calcium deficiency is a constant menace to land-abiding animals, including mammals. Humans enjoying exceptional longevity on earth are especially susceptible to calcium deficiency in old age. Low calcium and vitamin D intake, short solar exposure, decreased intestinal absorption, and falling renal function with insufficient 1,25(OH)2 vitamin D biosynthesis all contribute to calcium deficiency, secondary hyperparathyroidism, bone loss and possibly calcium shift from the bone to soft tissue, and from the extracellular to the intracellular compartment, blunting the sharp concentration gap between these compartments. The consequences of calcium deficiency might thus include not only osteoporosis, but also arteriosclerosis and hypertension due to the increase of calcium in the vascular wall, amyotrophic lateral sclerosis and senile dementia due to calcium deposition in the central nervous system, and a decrease in cellular function, because of blunting of the difference in extracellular-intracellular calcium, leading to diabetes mellitus, immune deficiency and others (Fig. 6). PMID:2943880

  6. Transport of Calcium Ions into Mitochondria.

    Science.gov (United States)

    Xu, Zhaolong; Zhang, Dayong; He, Xiaolan; Huang, Yihong; Shao, Hongbo

    2016-06-01

    To uptake calcium ions of mitochondria is of significant functional connotation for cells, because calcium ions in mitochondria are involved in energy production, regulatory signals transfer, and mitochondrial permeability transition pore opening and even programmed cell death of apoptosis, further playing more roles in plant productivity and quality. Cytoplasmic calcium ions access into outer mitochondrial membrane (OMM) from voltage dependent anion-selective channel (VDAC) and were absorbed into inner mitochondrial membrane (IMM) by mitochondrial calcium uniporter (MCU), rapid mitochondrial calcium uptake (RaM) or mitochondrial ryanodine receptor (mRyR). Although both mitochondria and the mechanisms of calcium transport have been extensively studied, but there are still long-standing or even new challenges. Here we review the history and recent discoveries of the mitochondria calcium ions channel complex involved calcium assimilation, and discuss the role of calcium ions into mitochondria. PMID:27252588

  7. Optimizing calcium selective fluorimetric nanospheres.

    Science.gov (United States)

    Kisiel, Anna; Kłucińska, Katarzyna; Gniadek, Marianna; Maksymiuk, Krzysztof; Michalska, Agata

    2015-11-01

    Recently it was shown that optical nanosensors based on alternating polymers e.g. poly(maleic anhydride-alt-1-octadecene) were characterized by a linear dependence of emission intensity on logarithm of concentration over a few of orders of magnitude range. In this work we focus on the material used to prepare calcium selective nanosensors. It is shown that alternating polymer nanosensors offer competitive performance in the absence of calcium ionophore, due to interaction of the nanospheres building blocks with analyte ions. The emission increase corresponds to increase of calcium ions contents in the sample within the range from 10(-4) to 10(-1) M. Further improvement in sensitivity (from 10(-6) to 10(-1) M) and selectivity can be achieved by incorporating calcium ionophore in the nanospheres. The optimal results were obtained for core-shell nanospheres, where the core was prepared from poly(styrene-co-maleic anhydride) and the outer layer from poly(maleic anhydride-alt-1-octadecene). Thus obtained chemosensors were showing linear dependence of emission on logarithm of calcium ions concentration within the range from 10(-7) to 10(-1) M. PMID:26452839

  8. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    International Nuclear Information System (INIS)

    By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca9Sr(PO4)6(OH)2 - CaSr9(PO4)6(OH)2. The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice

  9. Optimized geometry, vibration (IR and Raman spectra and nonlinear optical activity of p-nitroanilinium perchlorate molecule: A theoretical study

    Directory of Open Access Journals (Sweden)

    Tamer Ömer

    2016-03-01

    Full Text Available The molecular modeling of p-nitroanilinium perchlorate molecule was carried out by using B3LYP and HSEH1PBE levels of density functional theory (DFT. The IR and Raman spectra were simulated and the assignments of vibrational modes were performed on the basis of relative contribution of various internal co-ordinates. NBO analysis was performed to demonstrate charge transfer, conjugative interactions and the formation of intramolecular hydrogen bonding interactions within PNAPC. Obtained large dipole moment values showed that PNAPC is a highly polarizable complex, and the charge transfer occurs within PNAPC. Hydrogen bonding and charge transfer interactions were also displayed by small HOMO-LUMO gap and molecular electrostatic potential (MEP surface. The strong evidences that the material can be used as an efficient nonlinear optical (NLO material of PNAPC were demonstrated by considerable polarizability and hyperpolarizability values obtained at DFT levels.

  10. Synthesis of N-(3-(Dimethylamino)-2-(4-Ethoxyphenyl) Alllidene)-N-Methylmethanaminium Perchlorate by Willgerodt-Kindler Reaction

    Institute of Scientific and Technical Information of China (English)

    REN Wei-min; WANG Xing-yong; YANG Hai-tao; SHI Gui-zhen; LI Feng

    2006-01-01

    Liquid crystals containing phenylpyrimidine units are the fascination condensed state of soft matter with unique electrical, optical and mechanical properties. In this paper, a novel and efficient route was reported for the synthesis of N-(3-(dimethylamino)-2-(4-ethoxyphenyl)allylidene)-N-methylmethanaminium perchlorate by the WillgerodtKindler reaction, which can be further applied to prepare liquid crystals containing phenylpyrimidine units. The product was confirmed by 1HNMR, MS, FT-IR and elemental analysis. The experimental conditions of the Willgerodt-Kindler reaction were also studied and the results show that the yield ofp-ethoxyphenyl-acetic acid increased remarkably with a reaction time up to 60 min, then decreased due to carbonization. On the other hand, the yield was also influenced by microwave power. It increased from 20.6 % to 78.8 % with a rise in the microwave power from 250 W to 450 W, but the product was carbonized at 640 W.

  11. Optimized pyroelectric properties of 0-3 composites of PZT particles in polyurethane doped with lithium perchlorate.

    Science.gov (United States)

    Ploss, Bernd; Krause, Markus

    2007-12-01

    A substantial improvement in the performance of pyroelectric 0-3 composites of ceramic particles in a polymer matrix has been achieved by doping the polymer matrix material. Readily prepared and polarized films with various volume fractions of lead zirconate-titanate (PZT) particles in polyurethane have been doped in a solution of lithium perchlorate in acetone to increase the conductivity. With an appropriate conductivity, the dielectric permittivities of the ceramic particles and the polymer matrix become matched, resulting in an improvement of the pyroelectric coefficient from about 6 microC/(m(2)K) to about 50 microC/(m(2)K). The experimental results are explained by theoretical predictions. PMID:18276541

  12. Spectrophotometric determination of microamounts of thorium with thorin in the presence of cetylpyridinium chloride as surfactant in perchloric acid

    International Nuclear Information System (INIS)

    A simple and more sensitive spectrophotometric method is developed for determination of thorium using thorin as a chromogenic reagent in the presence of cetylpyridinium chloride (CPC) in perchloric acid. The reaction was instantaneous and complex was found stable for 168 h. A significant bathochromic shift was noted in the presence of CPC. The determination range was enhanced from 25 to 30 μg mL-1 with molar absorptivity of 2.95 × 104 L mol-1 cm-1 at 25 ± 5 deg C. Sandell's sensitivity was calculated to be 6.8 ng cm-2 at 581 nm. Relative standard deviation was reduced from 4.25 to 2.5. The interference of Ni2+, Mn2+, Sn4+, phosphate, EDTA, sulphate and tartrate has been reduced significantly in the presence of surfactant. The validity of the proposed method was tested by determining thorium in Certified Reference Materials. (author)

  13. Effects of addition of surfactants on viscosity of uncured ammonium perchlorate(A/P)/hydroxyl-terminated polybutadiene (HTPB) propellant

    Energy Technology Data Exchange (ETDEWEB)

    Koga, M.; Hagihara, Y. [National Defense Academy, Kanagawa (Japan)

    1998-08-31

    In production of ammonium perchlorate (AP)/hydroxyl-terminated polybutadiene (HTPB) propellants, it is preferable that the uncured propellant has a low viscosity during the mixing and forming processes. In this study, effects of surfacant on viscosity of the uncured propellant are studied for a total of 11 types of surfacants. It is found that sodium lauryl sulfate decreases viscosity of the AP/HTPB mixture more efficiently than any other surfacants tested. Apparent viscosity decreases by 30%, and its optimum dosage will be 0.005wt% based on the mixture to sufficiently decrease viscosity of the mixture. Viscosity of the mixture can be also decreased by improving wettability between AP and HTPB prepolymer. Sodium lauryl sulfate also shows an effect of delaying the potlife, i.e., time extending from addition of a curing agent to a thermosetting resin until it is cured to be unserviceable. 6 refs., 4 figs., 2 tabs.

  14. Synthesis of chrysalis-like CuO nanocrystals and their catalytic activity in the thermal decomposition of ammonium perchlorate

    Indian Academy of Sciences (India)

    Jun Wang; Shanshan He; Zhanshuang Li; Xiaoyan Jing; Milin Zhang; Zhaohua Jiang

    2009-11-01

    Chrysalis-like morphologies of CuO have been synthesized in large-quantity via a simple chemical deposition method without the use of any complex instruments and reagents. CuO nanocrystals showed a different morphology at three different temperatures, 25, 60 and 100°C. The particle size, morphology and crystal structure of the samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectra. The catalytic effect of CuO nanoparticles on the decomposition of ammonium perchlorate (AP) was investigated by STA 409 PC thermal analyzer at a heating rate of 10°C min-1 from 35 to 500°C. Compared with the thermal decomposition of pure AP, the addition of CuO nanoparticles decreased the decomposition temperature of AP by about 85°C.

  15. Synthesis of CNTs/CuO and its catalytic performance on the thermal decomposition of ammonium perchlorate

    Directory of Open Access Journals (Sweden)

    Ping Cui

    2016-05-01

    Full Text Available Copper oxide (CuO nanoparticles were successfully deposited on carbon nanotubes’ (CNTs surface via complex-precipitation method, the nanocomposite was characterized by transmission electron microscopy (TEM, scanning electron microscopy (SEM, X-ray photoelectron spectroscopy (XPS, X-ray powder diffraction (XRD, Raman spectroscopy, Fourier transform infrared (FT-IR and Brunauer–Emmett–Teller (BET. The catalytic performance of CNTs/CuO on ammonium perchlorate (AP decomposition was analyzed by differential thermal analyzer (DTA, the DTA results showed its excellent catalytic effect on AP decomposition, as 8 wt.% CNTs/CuO was added in AP, the second exothermic peak temperature decreased by 158 °C. Such composite may be a promising candidate for catalyzing the AP thermal decomposition.

  16. Thermal, optical, mechanical and electrical properties of a novel NLO active L-phenylalanine L-phenylalaninium perchlorate single crystals

    International Nuclear Information System (INIS)

    Single crystals of L-phenylalanine L-phenylalaninium perchlorate (LPAPCl), a semiorganic nonlinear (NLO) material have been successfully grown up to a size of 14 mmx5 mmx3 mm. The lattice parameters of the grown crystals are determined by single crystal XRD. The UV-Vis-NIR spectrum of LPAPCl show less optical absorption in the entire visible region. Nonlinear optical study reveals that the SHG efficiency of LPAPCl is nearly 1.4 times that of KDP. The laser damage density is found to be 7.4 GW/cm2. The crystals are subjected to microhardness studies and the variation of the microhardness with the applied load is studied. The response of dielectric constant in the frequency region of 50 Hz to 5 MHz has been investigated. AC and DC conductivity and photoconductivity experiments are also carried out and the results are discussed.

  17. Solution enthalpy of lithium perchlorate in diethyl ether, acetone, acetonitrile, dimethyl sulfoxide and effects of cycloaddition reactions acceleration

    International Nuclear Information System (INIS)

    Integral solution enthalpies of lithium perchlorate in diethyl ether, acetonitrile, acetone and DMSO at 298,2 K are determined calorimetrically; they are equal to -6.2, -9.1, -15.9 and -18.0 kcal/mol correspondingly. For diethyl ether dependence of integral solution enthalpy on salt concentration within the range from 3 x 10-3 up to 5,6 mol/l is determined. Reducing exoeffect of salt dissolution in the ether from -6 up to -5 kcal/mol in the range of small concentrations (3 x 10-3 - 3 x 10-2 mol/l), the constancy of the effect in the 5 x 10-2 - 1.3 mol/l range and following smooth reducing exoeffect up to -3.2 kcal/mol at salt concentration 5.6 mol/l is pointed out

  18. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Ueda, Yukari; Taira, Zenei

    2013-01-01

    We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 mg/kg, and is not affected by anions. Results after oral calcium administration of 150 mg/kg showed that the intes...

  19. Novel perchlorate and phosphate salts of vinpocetine: Characterization, relative solid-state stability evaluation and Hirshfeld surface analysis

    Science.gov (United States)

    Ma, Yu-heng; Ge, Shu-wang; Wang, Wei; Zheng, Qiang; Zuo, Yun-wei; Zhong, Chang-jiang; Sun, Bai-wang

    2016-02-01

    Salt formation is a very common and effective method of improving a drug's physicochemical properties such as hygroscopicity and physical stability at different humidity conditions. Aqueous solubility is another important parameter that can be improved by salt formation; however this strategy has not yet been evaluated for the important alkaloid drug, Vinpocetine. A poorly water-soluble basic drug (water solubility value≈ 5 μg/ml and pKa value of 7.31), vinpocetine was converted into two novel salts in this work, with perchloric acid and phosphoric acid in a 1: 1 M ratio. However, an unexpected phase transformation occurred in one of the salts after the stability test, which is a major concern in studies on dosage form. The conversion of the salt to free base could be related to the temperature-humidity profile of the type II salt (formed by vinpocetine and phosphoric acid). When the temperature was more than 70 °C under high humidity conditions of more than 80%, the phase transformation occurred immediately. To gain further understanding of this phenomenon, single crystals of the two novel salts were prepared and characterized by single crystal X-ray diffraction, Powder-XRD, infrared spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Constituents of the crystalline phase were also investigated in terms of Hirshfeld surface. The structures were found to be stabilized by H⋯H, C-H⋯O, O-H⋯N and C-H⋯π intermolecular interactions. Our stability studies showed that both these two novel salts could improve the stability of vinpocetine, however the type I salt (formed by vinpocetine and perchloric acid) offers more advantages. This finding will provide valuable information for vinpocetine dosage form development.

  20. Calcium release-activated calcium current in rat mast cells.

    Science.gov (United States)

    Hoth, M; Penner, R

    1993-06-01

    1. Whole-cell patch clamp recordings of membrane currents and fura-2 measurements of free intracellular calcium concentration ([Ca2+]i) were used to study the biophysical properties of a calcium current activated by depletion of intracellular calcium stores in rat peritoneal mast cells. 2. Calcium influx through an inward calcium release-activated calcium current (ICRAC) was induced by three independent mechanisms that result in store depletion: intracellular infusion of inositol 1,4,5-trisphosphate (InsP3) or extracellular application of ionomycin (active depletion), and intracellular infusion of calcium chelators (ethylene glycol bis-N,N,N',N'-tetraacetic acid (EGTA) or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)) to prevent reuptake of leaked-out calcium into the stores (passive depletion). 3. The activation of ICRAC induced by active store depletion has a short delay (4-14 s) following intracellular infusion of InsP3 or extracellular application of ionomycin. It has a monoexponential time course with a time constant of 20-30 s and, depending on the complementary Ca2+ buffer, a mean normalized amplitude (at 0 mV) of 0.6 pA pF-1 (with EGTA) and 1.1 pA pF-1 (with BAPTA). 4. After full activation of ICRAC by InsP3 in the presence of EGTA (10 mM), hyperpolarizing pulses to -100 mV induced an instantaneous inward current that decayed by 64% within 50 ms. This inactivation is probably mediated by [Ca2+]i, since the decrease of inward current in the presence of the fast Ca2+ buffer BAPTA (10 mM) was only 30%. 5. The amplitude of ICRAC was dependent on the extracellular Ca2+ concentration with an apparent dissociation constant (KD) of 3.3 mM. Inward currents were nonsaturating up to -200 mV. 6. The selectivity of ICRAC for Ca2+ was assessed by using fura-2 as the dominant intracellular buffer (at a concentration of 2 mM) and relating the absolute changes in the calcium-sensitive fluorescence (390 nm excitation) with the calcium current integral

  1. Calcium phosphate in catheter encrustation.

    Science.gov (United States)

    Cox, A J; Harries, J E; Hukins, D W; Kennedy, A P; Sutton, T M

    1987-02-01

    Encrusted catheters from nine female patients were the source of samples of deposits which were examined by X-ray diffraction, atomic absorption spectroscopy, infra-red spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. In eight samples the only crystalline phase which could be clearly distinguished by X-ray diffraction was ammonium magnesium orthophosphate hexahydrate, NH4MgPO4 X 6H2O, which occurs naturally as the mineral struvite. However, atomic absorption spectroscopy revealed an appreciable concentration of calcium in all samples. Calcium phosphates have previously been detected in catheter deposits. Infra-red and EXAFS spectra were consistent with the calcium phosphate being present as a poorly crystalline hydroxyapatite. Thus the deposits appear to consist of a mixture of crystalline struvite and a form of hydroxyapatite which is not fully crystalline. PMID:3030487

  2. The effect of variable calcium and very low calcium diets on human calcium metabolism. Ph.D. Thesis. Final Report

    Science.gov (United States)

    Chu, J.

    1971-01-01

    The effects of a very low calcium diet, with variable high and low protein intake, on the dynamics of calcium metabolism and the mechanism of calciuretics, are examined. The experiment, using male subjects, was designed to study the role of intestinal calcium absorption on urinary calcium excretion, and the rate of production of endogeneously secreted calcium in the gastrointestinal tract. The study showed an average of 70% fractional absorption rate during very low calcium intake, and that a decrease in renal tubular reabsorption of calcium is responsible for calciuretic effects of high protein intake. The study also indicates that there is a tendency to develop osteoporosis after long periods of low calcium intake, especially with a concurrent high protein intake.

  3. Tumoral calcium pyrophosphate deposition disease

    International Nuclear Information System (INIS)

    A report of two patients in which a soft tissue mass, initially regarded as a malignant tumor, was shown to be the result of calcium pyrophosphate deposition disease. The first case, a woman aged 71 years, presented with a mass involving the right fifth finger. In the second case, also a women aged 71 years, the lesion involved the tissues adjacent to the right hip. Each lesion consisted of a mass of highly cellular tissue containing deposits of calcium pyrophosphate dihydrate crystals. The clinical, radiological, and pathological features of the two cases are compared with those of seven similar cases reported in the literature. (orig.)

  4. The perchlorate discharge test with {sup 123}I for the diagnosis of the Pendred syndrome in children; Der Depletionstest mit {sup 123}Iod zur Diagnose des Pendred-Syndroms bei Kindern

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, K.; Fischer, S. [Klinik und Poliklinik fuer Nuklearmedizin, Klinikum der Ludwig-Maximilians-Univ. Muenchen (Germany)

    2009-03-15

    The method for the diagnosis of the Pendred Syndrome in children by the Perchlorate discharge test using {sup 123}I is described. The older child, who has the Pendred Syndrome and the obligatory hearing deficit, frequently has neither a goitre nor hypothyroidism, but other investigations (bone growth, scars and function tests) can also show changes. However a more certain diagnosis of this disorder in children is possible by the perchlorate discharge test using {sup 123}I. (orig.)

  5. Complex formation ions calcium with macromolecules pectin

    International Nuclear Information System (INIS)

    In clause the mechanism of sorption of ions of calcium by macromolecules of pectin is opened. Is shown, that the linkage of ions of calcium descends on acid bunches of pectin, and process carries cooperative character

  6. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Devkanya Dutta

    2000-12-01

    Activation of receptors coupled to the phospholipase C/IP3 signalling pathway results in a rapid release of calcium from its intracellular stores, eventually leading to depletion of these stores. Calcium store depletion triggers an influx of extracellular calcium across the plasma membrane, a mechanism known as the store-operated calcium entry or capacitative calcium entry. Capacitative calcium current plays a key role in replenishing calcium stores and activating various physiological processes. Despite considerable efforts, very little is known about the molecular nature of the capacitative channel and the signalling pathway that activates it. This review summarizes our current knowledge about store operated calcium entry and suggests possible hypotheses for its mode of activation.

  7. Dairy Dilemma: Are You Getting Enough Calcium?

    Science.gov (United States)

    ... Dairy Dilemma Dairy Dilemma Are You Getting Enough Calcium? You may be avoiding dairy products because of ... But dairy products are a major source of calcium, vitamin D and other nutrients that are important ...

  8. Calcium, vitamin D, and your bones

    Science.gov (United States)

    ... can break easily, even without an obvious injury. Vitamin D helps your body absorb calcium. Eat foods that provide the right amounts of calcium, vitamin D, and protein. This kind of diet will give ...

  9. Calcium channel blockers and Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Yi Tan; Yulin Deng; Hong Qing

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofi-brillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers in-volved in Alzheimer's disease therapy.

  10. Calcium channel blockers and Alzheimer's disease★

    OpenAIRE

    Tan, Yi; Deng, Yulin; Qing, Hong

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofibrillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers involved in...

  11. Teaching Calcium-Induced Calcium Release in Cardiomyocytes Using a Classic Paper by Fabiato

    Science.gov (United States)

    Liang, Willmann

    2008-01-01

    This teaching paper utilizes the materials presented by Dr. Fabiato in his review article entitled "Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum." In the review, supporting evidence of calcium-induced calcium release (CICR) is presented. Data concerning potential objections to the CICR theory are discussed as well. In…

  12. Electrophysical properties of calcium orthovanadate

    International Nuclear Information System (INIS)

    The electron conductivity, dielectric permeability and magnetic susceptibility of calcium orthovanadate are studied. It is shown that structural transformations bring about changes in the nature of electrophysical properties of Ca3(VO4)2 and cause the charge redistribution in VO43- anion groups

  13. 21 CFR 582.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  14. 21 CFR 182.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  15. 21 CFR 582.5217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.5217 Section 582.5217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  16. 21 CFR 582.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.1191 Section 582.1191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  17. 21 CFR 582.5191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.5191 Section 582.5191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  18. 21 CFR 73.1070 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1070 Calcium carbonate. (a) Identity. (1) The color additive calcium carbonate is a fine,...

  19. 21 CFR 582.1205 - Calcium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  20. 21 CFR 182.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 182.2227 Section 182.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2227 Calcium silicate. (a) Product. Calcium silicate....

  1. 21 CFR 582.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 582.2227 Section 582.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c)...

  2. Calcium dynamics in vascular smooth muscle

    OpenAIRE

    Amberg, Gregory C.; Navedo, Manuel F.

    2013-01-01

    Smooth muscle cells are ultimately responsible for determining vascular luminal diameter and blood flow. Dynamic changes in intracellular calcium are a critical mechanism regulating vascular smooth muscle contractility. Processes influencing intracellular calcium are therefore important regulators of vascular function with physiological and pathophysiological consequences. In this review we discuss the major dynamic calcium signals identified and characterized in vascular smooth muscle cells....

  3. Lactulose stimulates calcium absorption in postmenopausal women

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muijs, T.; Dokkum, W. van; Schaafsma, G.

    1999-01-01

    Animal studies have indicated that calcium absorption is increased by lactulose, a synthetic disaccharide. Therefore, the influence of lactulose on calcium absorption was measured in postmenopausal women who may benefit from the possible enhancing effect of lactulose on calcium absorption. Twelve po

  4. Oxidation of alginate and pectate biopolymers by cerium(IV) in perchloric and sulfuric acid solutions: A comparative kinetic and mechanistic study.

    Science.gov (United States)

    Fawzy, Ahmed

    2016-03-15

    The kinetics of oxidation of alginate (Alg) and pectate (Pec) carbohydrate biopolymers was studied by spectrophotometry in aqueous perchloric and sulfuric acid solutions at fixed ionic strengths and temperature. In both acids, the reactions showed a first order dependence on [Ce(IV)], whereas the orders with respect to biopolymer concentrations are less than unity. In perchloric acid, the reactions exhibited less than unit orders with respect to [H(+)] whereas those proceeded in sulfuric acid showed negative fractional-first order dependences on [H(+)]. The effect of ionic strength and dielectric constant was studied. Probable mechanistic schemes for oxidation reactions were proposed. In both acids, the final oxidation products were characterized as mono-keto derivatives of both biopolymers. The activation parameters with respect to the slow step of the mechanisms were computed and discussed. The rate laws were derived and the reaction constants involved in the different steps of the mechanisms were calculated. PMID:26794772

  5. Control of Sulfidogenesis Through Bio-oxidation of H2S Coupled to (per)chlorate Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gregoire, Patrick [Univ. of California, Berkeley, CA (United States); Engelbrektson, Anna [Univ. of California, Berkeley, CA (United States); Hubbard, Christopher G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Metlagel, Zoltan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Csencsits, Roseann [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Auer, Manfred [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Conrad, Mark E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thieme, Jurgen [Brookhaven National Lab. (BNL), Upton, NY (United States); Northrup, Paul [Brookhaven National Lab. (BNL), Upton, NY (United States); Coates, John D. [Univ. of California, Berkeley, CA (United States)

    2014-04-04

    Here, we investigate H2S attenuation by dissimilatory perchlorate-reducing bacteria (DPRB). All DPRB tested oxidized H2S coupled to (per)chlorate reduction without sustaining growth. H2S was preferentially utilized over organic electron donors resulting in an enriched (34S)-elemental sulfur product. Electron microscopy revealed elemental sulfur production in the cytoplasm and on the cell surface of the DPRB Azospira suillum. We also propose a novel hybrid enzymatic-abiotic mechanism for H2S oxidation similar to that recently proposed for nitrate-dependent Fe(II) oxidation. The results of this study have implications for the control of biosouring and biocorrosion in a range of industrial environments.

  6. Sodium/Calcium Exchangers Selectively Regulate Calcium Signaling in Mouse Taste Receptor Cells

    OpenAIRE

    Szebenyi, Steven A.; Laskowski, Agnieszka I.; Medler, Kathryn F.

    2010-01-01

    Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium release from intracellular stores while other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). While the signaling mechanisms that initiate calcium signals have been described in taste cells, the calcium clearance mechanisms (CCMs) that contrib...

  7. Calcium electroporation in three cell lines; a comparison of bleomycin and calcium, calcium compounds, and pulsing conditions

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gissel, Hanne; Hojman, Pernille;

    2013-01-01

    BACKGROUND: Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation...... offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium...... electroporation and electrochemotherapy. METHODS: The effects of calcium electroporation and bleomycin electroporation (alone or in combination) were compared in three different cell lines (DC-3F, transformed Chinese hamster lung fibroblast; K-562, human leukemia; and murine Lewis Lung Carcinoma). Furthermore...

  8. Limited overshooting of NH{sub 4}{sup +} ions in ammonium perchlorate; Ograniczene przeskoki jonow NH{sub 4}{sup +} w nadchloranie amonowym

    Energy Technology Data Exchange (ETDEWEB)

    Birczynski, A.; Lalowicz, Z.T. [Inst. of Nuclear Physics, Cracow (Poland); Ingman, L.P.; Punkkinen, M.; Ylinen, E.E. [Wihuri Physical Lab., Turku Univ., Turku (Finland)

    1995-12-31

    The interpretation of NMR spectra for polycrystalline sample of ammonium perchlorate in helium temperature assumes the tunneling of NH{sub 4}{sup +}. Such interpretation does not agree with experimental data. The hypothesis of additional motion (fast rotation around one of C3 axis) has been checked and discussed on the base of NMR spectra of NH{sub 4}ClO{sub 4} monocrystal for the temperature range 2.1-25 K. 9 refs, 1 fig.

  9. Hirshfeld surface analysis of the 1,1´-(ethane-1,2-diyl)dipyridinium dication in two new salts: perchlorate and peroxodisulfate

    Czech Academy of Sciences Publication Activity Database

    Gholizadeh, M.; Pourayoubi, M.; Farimaneh, M.; Tarahhomi, A.; Dušek, Michal; Eigner, Václav

    2014-01-01

    Roč. 70, FEB (2014), s. 230-235. ISSN 0108-2701 Grant ostatní: AV ČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : crystal structure * Hirshfeld surface analysis * fingerprint plots * perchlorate salt * peroxodisulfate salt * 1,1'-(ethane-1,2-diyl)dipyridinium dication Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.326, year: 2014

  10. Immunological detection of small organic molecules in the presence of perchlorates: relevance to the life marker chip and life detection on Mars.

    OpenAIRE

    Rix, Catherine S.; Sims, Mark R.; Cullen, David C.

    2011-01-01

    The proposed ExoMars mission, due to launch in 2018, aims to look for evidence of extant and extinct life in martian rocks and regolith. Previous attempts to detect organic molecules of biological or abiotic origin on Mars have been unsuccessful, which may be attributable to destruction of these molecules by perchlorate salts during pyrolysis sample extraction techniques. Organic molecules can also be extracted and measured with solvent-based systems. The ExoMars payload inc...

  11. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Zenei Taira, Zenei

    2013-01-01

    Yukari Ueda, Zenei TairaFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, JapanAbstract: We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 ...

  12. Calcium signals and calcium channels in osteoblastic cells

    Science.gov (United States)

    Duncan, R. L.; Akanbi, K. A.; Farach-Carson, M. C.

    1998-01-01

    Calcium (Ca2+) channels are present in non-excitable as well as in excitable cells. In bone cells of the osteoblast lineage, Ca2+ channels play fundamental roles in cellular responses to external stimuli including both mechanical forces and hormonal signals. They are also proposed to modulate paracrine signaling between bone-forming osteoblasts and bone-resorbing osteoclasts at local sites of bone remodeling. Calcium signals are characterized by transient increases in intracellular Ca2+ levels that are associated with activation of intracellular signaling pathways that control cell behavior and phenotype, including patterns of gene expression. Development of Ca2+ signals is a tightly regulated cellular process that involves the concerted actions of plasma membrane and intracellular Ca2+ channels, along with Ca2+ pumps and exchangers. This review summarizes the current state of knowledge concerning the structure, function, and role of Ca2+ channels and Ca2+ signals in bone cells, focusing on the osteoblast.

  13. Computational study of a calcium release-activated calcium channel

    Science.gov (United States)

    Talukdar, Keka; Shantappa, Anil

    2016-05-01

    The naturally occurring proteins that form hole in membrane are commonly known as ion channels. They play multiple roles in many important biological processes. Deletion or alteration of these channels often leads to serious problems in the physiological processes as it controls the flow of ions through it. The proper maintenance of the flow of ions, in turn, is required for normal health. Here we have investigated the behavior of a calcium release-activated calcium ion channel with pdb entry 4HKR in Drosophila Melanogaster. The equilibrium energy as well as molecular dynamics simulation is performed first. The protein is subjected to molecular dynamics simulation to find their energy minimized value. Simulation of the protein in the environment of water and ions has given us important results too. The solvation energy is also found using Charmm potential.

  14. Molecular preservation in halite- and perchlorate-rich hypersaline subsurface deposits in the Salar Grande basin (Atacama Desert, Chile): Implications for the search for molecular biomarkers on Mars

    Science.gov (United States)

    FernáNdez-Remolar, D. C.; Chong-DíAz, G.; RuíZ-Bermejo, M.; Harir, M.; Schmitt-Kopplin, P.; Tziotis, D.; Gómez-OrtíZ, D.; GarcíA-Villadangos, M.; MartíN-Redondo, M. P.; Gómez, F.; RodríGuez-Manfredi, J. A.; Moreno-Paz, M.; de Diego-Castilla, G.; EcheverríA, A.; Urtuvia, V. N.; Blanco, Y.; Rivas, L.; Izawa, M. R. M.; Banerjee, N. R.; Demergasso, C.; Parro, V.

    2013-06-01

    Similarities between the Atacama Desert (Chile) and Mars include extreme aridity, highly oxidizing chemistry, and intense ultraviolet radiation that promoted the photochemical production of perchlorates and nitrates. Concentration of these ions under hyperarid conditions led to the formation of nitrate- and perchlorate-bearing deposits in ephemeral lakes, followed by later deposition of chlorides and sulfates. At some locations, such as the Salar Grande, hypersaline deposits have remained unaltered for millions of years. We conducted a drilling campaign in deposits of the Salar to characterize the preservation state of biological molecules. A 5 m deep discontinuous core was recovered and subjected to multitechnique analysis including the antibody microarray-based biosensor LDChip300 and the SOLID (Signs Of Life Detector) instrument, complemented by geophysical, mineralogical, geochemical, and molecular analysis. We identified two units based on the mineralogy: the upper one, from the surface to ~320 cm depth characterized by a predominance of halite and anhydrite, and the lower one, from 320 to 520 cm, with a drop in halite and anhydrite and an enrichment in nitrate and perchlorate. Organic compounds including biomolecules were detected in association with the different depositional and mineralogical units, demonstrating the high capacity for molecular preservation. Hypersaline environments preserve biomolecules over geologically significant timescales; therefore, salt-bearing materials should be high-priority targets for the search for evidence of life on Mars.

  15. The Investigation of Magnesium Perchlorate/Iron Phase-mineral Mixtures as a Possible Source of Oxygen and Chlorine Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

    Science.gov (United States)

    Sutter, B.; Heil, E.; Archer, P. D.; Ming, D. W.; Eigenbrode, J. L.; Franz, H. B.; Glavin, D. P.; McAdam, A. C.; Mahaffy, P. R.; Niles, P. B.; Stern, J. C.; Navarro-Gonzalez, R.; McKay, C. P.

    2014-01-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detect-ed O2 and HCl gas releases from the Rocknest (RN) eolian bedform and the John Klein (JK) and Cumber-land (CB) drill hole materials in Gale Crater (Fig. 1) [1,2]. Chlorinated hydrocarbons have also been detect-ed by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS) [1,2,3,4]. These detections along with the detection of perchlorate (ClO4(-)) by the Mars Phoenix Lander's Wet Chemistry Laboratory (WCL) [5] suggesting perchlo-rate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of individual per-chlorates has yet to provide an unequivocal tempera-ture match to the SAM O2 and HCl release data [1,2]. Catalytic reactions of Fe phases in the Gale Crater ma-terial with perchlorates can potentially reduce the de-composition temperatures of these otherwise pure per-chlorate/chlorate phases [e.g., 6,7]. Iron mineralogy found in the Rocknest materials when mixed with Ca-perchlorate was found to cause O2 release temperatures to be closer match to the SAM O2 release data and enhance HCl gas releases. Exact matches to the SAM data has unfortnunately not been achieved with Ca-perchlorate-Fe-phase mixtures [8]. The effects of Fe-phases on magnesium perchlorate thermal decomposi-tion release of O2 and HCl have not been evaluated and may provide improved matches to the SAM O2 and HCl release data. This work will evaluate the thermal decomposition of magnesium perchlorate mixed with fayalite/magnetite phase and a Mauna Kea palagonite (HWMK 919). The objectives are to 1) summarize O2 and HCl releases from the Gale Crater materials, and 2) evaluate the O2 and HCl releases from the Mg-perchlorate + Fe phase mixtures to determine if Mg-perchlorate mixed with Fe-phases can explain the Gale Crater O2 and HCl releases.

  16. Substitution of calcium by strontium within selected calcium phosphates

    Science.gov (United States)

    Rokita, E.; Hermes, C.; Nolting, H.-F.; Ryczek, J.

    1993-06-01

    Sr incorporation in the molecules of amorphous calcium phosphate, apatitic tricalcium phosphate, hydroxyapatite, octacalcium phosphate and dicalcium phosphate dihydrate was investigated. The concentration of Sr ranged from 225 to 1010 μ g / g, i.e. it overlapped with the physiological range of Sr concentrations in human bone. The leading experimental technique was extended X-ray absorption fine structure (EXAFS) at the Sr K edge. Results of these studies demonstrated the following: (1) Sr incorporation in the calcium phosphates is compound-dependent, (2) the coordination of incorporated Sr atoms in the Ca-P molecules is similar to that of Ca atoms, but interatomic distances are ≈0.015 nm larger, (3) in apatitic tricalcium phosphate, hydroxyapatite and octacalcium phosphate lattices Sr atoms may occupy selected Ca sites, which was not the case for dicalcium phosphate dihydrate, (4) in the apatite lattice Sr atoms are coordinated by 6 PO 4 tetrahedrals and (5) EXAFS spectra at the K edge of the incorporated Sr may be used to distinguish the structures of amorphous calcium phosphate, dicalcium phosphate dihydrate as well as apatite and its derivatives (apatitic tricalcium phosphate, octacalcium phosphate).

  17. USING CALCIUM CARBONATE WHISKERS AS PAPERMAKING FILLER

    Directory of Open Access Journals (Sweden)

    Xiaoyu Chen

    2011-05-01

    Full Text Available Whiskers, having large length/diameter ratio, are fiber-shaped single crystals. The technical possibility of using calcium carbonate whiskers as papermaking filler to replace conventional powder-like calcium carbonate was investigated. The results showed that it may be feasible to use calcium carbonate whisker as papermaking filler. Compared with conventional precipitated calcium carbonate, calcium carbonate whisker had higher retention efficiency. The use of calcium carbonate whisker also favorably affected the strength properties of paper sheets. A model was proposed to suggest the mechanism for paper strength improvement. The whiskers filled in paper sheets could increase the friction between fibers, thus increasing bonding strength. Moreover, the strength properties of paper were further improved because calcium carbonate whiskers were partly embedded in pulp fiber walls.

  18. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    Directory of Open Access Journals (Sweden)

    Choksi Krishna

    2011-03-01

    Full Text Available The objective of present study is to evaluate the effects of calcium carbonate and calcium gluconate on acute and subacute inflammation and to study their possible interactions with Aspirin. Calcium carbonate (10 mg/kg and calcium gluconate (5 mg/kg were administered individually and also co-administered along with sub therapeutic dose Aspirin (50mg/kg to study their interaction. The inflammation was induced by carrageenan or a foreign body. Both calcium carbonate and calcium gluconate could not show significant anti-inflammatory activity on their own in acute as well as subacute inflammation models. Aspirin at sub-anti-inflammatory dose (50mg/Kg when co-administered along with calcium salts produced the significant anti-inflammatory response which was comparable to anti-inflammatory response of aspirin at therapeutic dose (200mg/Kg. Also co-adminostration minimized the gastro-toxicity of aspirin.

  19. [Calcium pyrophosphate dihydrate deposition disease].

    Science.gov (United States)

    Koitschev, C; Kaiserling, E; Koitschev, A

    2003-08-01

    Calcium pyrophosphate dihydrate deposition disease (CPPD) of the temporomandibular joint is rare. The disorder is characterized by the presence of crystal deposits within the affected joint. The deposition of crystals in adjacent soft tissue may lead to the formation of pseudotumors. This form of the disease is called tophaceous pseudogout and typically affects the temporomandibular joint. It is difficult to differentiate the disease, particularly from malignant tumors, on the clinical and radiographic findings alone. The diagnosis is based on histological identification of the calcium pyrophosphate crystals. We present an unusually advanced case of tophaceous pseudogout of the temporomandibular joint. The etiology, clinical and diagnostic criteria as well as treatment options are discussed on the basis of our own experience and a review of the literature. PMID:12942180

  20. Testosterone increases urinary calcium excretion and inhibits expression of renal calcium transport proteins

    DEFF Research Database (Denmark)

    Hsu, Yu-Juei; Dimke, Henrik Anthony; Schoeber, Joost P H;

    2010-01-01

    Although gender differences in the renal handling of calcium have been reported, the overall contribution of androgens to these differences remains uncertain. We determined here whether testosterone affects active renal calcium reabsorption by regulating calcium transport proteins. Male mice had...... higher urinary calcium excretion than female mice and their renal calcium transporters were expressed at a lower level. We also found that orchidectomized mice excreted less calcium in their urine than sham-operated control mice and that the hypocalciuria was normalized after testosterone replacement...... calcium transport. Thus, our study shows that gender differences in renal calcium handling are, in part, mediated by the inhibitory actions of androgens on TRPV5-mediated active renal calcium transport....

  1. Biological Reduction of Perchlorate and Optimization%生物法降解高氯酸盐及其优化研究

    Institute of Scientific and Technical Information of China (English)

    钱慧静; 奚胜兰; 何平; 徐新华

    2009-01-01

    The potential of bioremediation to treat perchlorate-contaminated water by acclimating anaerobic activated sludge was investigated in this study. Factors such as carbon source,initial pH,temperature,domesticated sludge concentration and dissolved oxygen affecting the removal of perchlorate were studied in detail by shaking-bottle point tests using acetate as carbon source. Results showed that 50 mg/L perchlorate was completely reduced by 1.0 g of domesticated sludge added with 1.2 g/L of acetate under the conditions of 35℃ and initial pH 8.0. Dissolved oxygen in the system would restrain the reduction of perchlorate. In addition,column bioreactor was used to treat perchlorate continuously,with the minimum residence time of 6 h.%利用经过驯化处理的厌氧活性污泥来处理高氯酸盐废水,以醋酸根为碳源,通过摇床实验考察了碳源浓度、pH值、生长温度、泥量和溶解氧等因素对高氯酸盐降解率的影响,初步确定最佳反应条件.结果表明,在35℃、初始pH值为 8.0的条件下,添加1.2 g/L的醋酸根,1.0 g厌氧培养的活性污泥能将50 mg/L的高氯酸盐完全降解.体系中的溶解氧会抑制高氯酸盐的降解.此外,还考察了生物膜柱反应器连续处理高氯酸盐模拟废水的效果,结果表明完全降解高氯酸盐的最小停留时间为6 h.

  2. Influence of calcium oxalate crystal accumulation on the calcium content of seeds from Medicago truncatula.

    Science.gov (United States)

    Nakata, Paul A

    2012-04-01

    Crystals of calcium oxalate often form in cells adjacent to the vascular bundles in the tissues along the xylem stream. This spatial crystal pattern suggests a role for calcium oxalate formation in regulating calcium transport and partitioning to edible organs such as seeds. To investigate this potential role, microscopic and biochemical comparisons were conducted on the different tissues of Medicago truncatula wild-type and the calcium oxalate defective (cod) 5 which lacks the ability to accumulate prismatic crystals in the cells adjacent to the vascular bundles. Calcium measurements showed that cod5 seeds had more calcium and cod5 pods contained less calcium than the corresponding wild-type tissues. Roots, stems, and leaves from cod5 and wild-type had similar calcium content. Although cod5 was devoid of prismatic crystals, cod5 pods were observed to form druse crystals of calcium oxalate not found in wild-type pods. Taken together these findings suggest a functional role for calcium oxalate formation in regulating calcium transport to the seeds. Regulating calcium uptake at the roots also appeared to be another point of control in determining seed calcium content. Overall, regulating the long distance transport and partitioning of calcium to the seeds appears to be a complex process with multiple points of control. PMID:22325887

  3. Serum calcium in pulmonary tuberculosis

    OpenAIRE

    Subhash C. Sharma

    1981-01-01

    Serum calcium was studied serially in 94 patients with active pulmonary tuberculosis. An equal number of age- and sex-matched patients with chronic obstructive pulmonary disease were controls. Seventy patients in the study group were normocalcaemic and 10 were hypercalcaemic. These 10 were on a higher supplement of vitamin D than the 70 normocalcaemic patients. There was a positive correlation between the daily vitamin intake and the degree and duration of hypercalcaemia. None of the controls...

  4. Drying dichloromethane over calcium hydride

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Lucas Kinard, Kurtis Kasper & Antonios Mikos ### Abstract This protocol describes the drying of dichloromethane by a simple 10 step procedure. One can implement this protocol using common lab glass and lab equipment. First, dichloromethane is refluxed with calcium hydride to remove water. Then, dichloromethane is distilled to separate it from the byproducts of the reflux reaction. This procedure can be implemented in 1 day. ### Introduction In many instances i...

  5. CCN3 and calcium signaling

    Directory of Open Access Journals (Sweden)

    Li Chang Long

    2003-08-01

    Full Text Available Abstract The CCN family of genes consists presently of six members in human (CCN1-6 also known as Cyr61 (Cystein rich 61, CTGF (Connective Tissue Growth Factor, NOV (Nephroblastoma Overexpressed gene, WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins. Results obtained over the past decade have indicated that CCN proteins are matricellular proteins, which are involved in the regulation of various cellular functions, such as proliferation, differentiation, survival, adhesion and migration. The CCN proteins have recently emerged as regulatory factors involved in both internal and external cell signaling. CCN3 was reported to physically interact with fibulin-1C, integrins, Notch and S100A4. Considering that, the conformation and biological activity of these proteins are dependent upon calcium binding, we hypothesized that CCN3 might be involved in signaling pathways mediated by calcium ions. In this article, we review the data showing that CCN3 regulates the levels of intracellular calcium and discuss potential models that may account for the biological effects of CCN3.

  6. The role of calcium in human aging.

    Science.gov (United States)

    Beto, Judith A

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance. PMID:25713787

  7. Rapid screening assay for calcium bioavailability studies

    International Nuclear Information System (INIS)

    Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium (47Ca) in a whole body retention assay system. In this system, calcium sources are administered by oral gavage and subsequent counts are determined and corrected for isotopic decay. Unlike iron and zinc retention curves, which exhibit a 2-3 day equilibration period, calcium reaches equilibration after 24 hours. Autoradiographic analysis of the femurs indicate that the newly absorbed calcium is rapidly distributed to the skeletal system. Moreover, the isotope is distributed along the entire bone. Comparisons of calcium bioavailability were made using intrinsic/extrinsic labeled milk from two species i.e. rat and goat as well as CaCO3. In addition, extrinsic labeled cow milk was examined. In the rat, the extrinsic labeled calcium from milk was better absorbed than the intrinsic calcium. This was not the case in goat milk or the calcium carbonate which exhibited no significant differences. Chromatographic analysis of the labeled milk indicates a difference in distribution of the 47Ca. From these data, the authors recommend the use of this assay system in calcium bioavailability studies. The labeling studies and comparisons indicate caution should be used, however, in labeling techniques and species milk comparison

  8. Highly Selective Liquid Membrane Sensor Based on 1,3,5-Triphenylpyrylium Perchlorate for Quick Monitoring of Sulfate Ions

    Energy Technology Data Exchange (ETDEWEB)

    Ganjali, Mohammad Reza; Ghorbani, Maryam; Daftari, Azadeh; Norouzi, Parviz; Pirelahi, Hooshang; Dargahani, Hossein Daryanavard [Tehran University, Tehran (Iran, Islamic Republic of)

    2004-02-15

    A highly selective membrane electrode based on 1,3,5-triphenylpyrylium perchlorate (TPPP) is presented. The proposed electrode shows very good selectivity for sulfate ions over a wide variety of common inorganic and organic anions. The sensor displays a nice Nernstian slope of -29.7 mV per decade. The working concentration ranges of the electrode is 1.0 x 10{sup -1} . 6.3 x 10{sup -6} M with a detection limit of 4.0 x 10{sup -6} M (480 ng per mL). The response time of the sensor in whole concentration ranges is very short (< 6 s). The response of the sensor is independent on the pH range of 2.5-9.5. The best performance was obtained with a membrane composition of 32% PVC, 59% benzyl acetate, 5% TPPP and 4% hexadecyltrimethylammonium bromide. It was successfully used as an indicator electrode for titration of sulfate ions with barium ions. The electrode was also applied for determination of salbutamol sulfate and paramomycine sulfate

  9. Specific interactions of functionalised gold surfaces with ammonium perchlorate or starch; towards a chemical cartography of their mixture

    Science.gov (United States)

    Mercier, D.; Mercader, C.; Quere, S.; Hairault, L.; Méthivier, C.; Pradier, C. M.

    2012-10-01

    By functionalising gold samples, planar wafers or AFM tips, with an acid- or an amino acid-terminated thiols, mercaptoundecanoic acid (MUA) and homocystein (H-Cyst) respectively, we were able to differentiate the interactions with ammonium perchlorate (AP) and starch (S), two components of a nanocomposition mixture. To do so, the interaction between gold functionalized surfaces and the two targeted compounds have been characterized and quantified by several complementary techniques. Polarisation modulation-infrared spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS), providing chemical analyses of gold surfaces after contacting S or AP, proved that both compounds were retained on MUA or H-Cyst-modified surfaces, but to various extents. Quartz crystal microbalance on-line measurements enabled to monitor the kinetics of interaction and showed distinct differences in the behaviour of MUA and H-Cyst-surfaces towards the two compounds. Having observed that only H-Cyst-modified surfaces enables to get a contrast on the chemical force microscopy (CFM) images, this new result could be well explained by examining the data obtained by combining the above-mentioned surface characterisation techniques.

  10. Specific interactions of functionalised gold surfaces with ammonium perchlorate or starch; towards a chemical cartography of their mixture

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, D. [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Mercader, C.; Quere, S.; Hairault, L. [CEA, DAM, Le Ripault, F-37260 Monts (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Methivier, C. [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Pradier, C.M., E-mail: claire-Marie.pradier@upmc.fr [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Measurements of interactions by Quartz Crystal Microbalance. Black-Right-Pointing-Pointer AFM and CFM measurements, tip functionalisation. Black-Right-Pointing-Pointer Surface nano-imaging. - Abstract: By functionalising gold samples, planar wafers or AFM tips, with an acid- or an amino acid-terminated thiols, mercaptoundecanoic acid (MUA) and homocystein (H-Cyst) respectively, we were able to differentiate the interactions with ammonium perchlorate (AP) and starch (S), two components of a nanocomposition mixture. To do so, the interaction between gold functionalized surfaces and the two targeted compounds have been characterized and quantified by several complementary techniques. Polarisation modulation-infrared spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS), providing chemical analyses of gold surfaces after contacting S or AP, proved that both compounds were retained on MUA or H-Cyst-modified surfaces, but to various extents. Quartz crystal microbalance on-line measurements enabled to monitor the kinetics of interaction and showed distinct differences in the behaviour of MUA and H-Cyst-surfaces towards the two compounds. Having observed that only H-Cyst-modified surfaces enables to get a contrast on the chemical force microscopy (CFM) images, this new result could be well explained by examining the data obtained by combining the above-mentioned surface characterisation techniques.

  11. Highly Selective Liquid Membrane Sensor Based on 1,3,5-Triphenylpyrylium Perchlorate for Quick Monitoring of Sulfate Ions

    International Nuclear Information System (INIS)

    A highly selective membrane electrode based on 1,3,5-triphenylpyrylium perchlorate (TPPP) is presented. The proposed electrode shows very good selectivity for sulfate ions over a wide variety of common inorganic and organic anions. The sensor displays a nice Nernstian slope of -29.7 mV per decade. The working concentration ranges of the electrode is 1.0 x 10-1 . 6.3 x 10-6 M with a detection limit of 4.0 x 10-6 M (480 ng per mL). The response time of the sensor in whole concentration ranges is very short (< 6 s). The response of the sensor is independent on the pH range of 2.5-9.5. The best performance was obtained with a membrane composition of 32% PVC, 59% benzyl acetate, 5% TPPP and 4% hexadecyltrimethylammonium bromide. It was successfully used as an indicator electrode for titration of sulfate ions with barium ions. The electrode was also applied for determination of salbutamol sulfate and paramomycine sulfate

  12. Syntheses and luminescence properties of two novel lanthanide (III) perchlorate complexes with phenacyl p-tolyl sulfoxide

    International Nuclear Information System (INIS)

    Two novel solid binary complexes of rare earth perchlorate with phenacyl p-tolyl sulfoxide were synthesized and characterized by elemental analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, 1HNMR and UV spectra. The results indicated that the composition of these complexes was REL7 (ClO4)3·6H2O (RE=Eu (III), Tb (III), L=C6H5COCH2SOC6H4CH3). The study on IR spectra and 1HNMR spectra revealed that phenacyl p-tolyl sulfoxide bonded with RE3+ ions by the oxygen atom in sulfinyl group. The emission spectra illustrated that both the Eu (III) and Tb (III) complexes displayed excellent luminescence in solid state, and The most intensive characteristic emission of the Eu(III) and Tb(III) complexes were 245,400 a.u. and 298,000 a.u. respectively. The slit with was 1 nm. By analysis luminescence and phosphorescence spectrum, it was found that the ligand had the advantage to absorb energy and transfer it to the Eu (III) and Tb (III) ions. The fluorescence lifetimes of the complexes were measured as well as the quantum yield of the Eu (III) complex

  13. The angiogenic effect of dracorhodin perchlorate on human umbilical vein endothelial cells and its potential mechanism of action.

    Science.gov (United States)

    Li, Feng; Jiang, Tao; Liu, Wei; Hu, Quan; Yin, Huinan

    2016-08-01

    Hyperglycemia is the key clinical feature of diabetes, and may induce refractory wound lesions and impaired angiogenesis. Dracorhodin perchlorate (Dra) is the major ingredient of dragon's blood and it has been used as a medicine to treat chronic wounds, such as diabetic foot, since ancient times in many cultures. The current study aimed to investigate the effect of Dra on human umbilical vein endothelial cells (HUVECs) under high‑glucose (HG) stimulation and its potential mechanism. Dra was observed to increase the multiplication capacity of HUVECs both under low glucose (LG) and HG concentrations. Additionally, migration and tube formation in HUVECs was facilitated by Dra. The expression levels of Ras, mitogen‑activated protein kinase (MAPK) and vascular endothelial growth factor, which are key components of the Ras/MAPK pathway, were upregulated following Dra treatment. The present study is the first report, to the best of our knowledge, of the effects of Dra on wound healing, and the association with the Ras/MAPK signaling pathway. PMID:27357516

  14. Syntheses and luminescence properties of two novel lanthanide (III) perchlorate complexes with phenacyl p-tolyl sulfoxide

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Shu-Yan [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Li, Wen-Xian, E-mail: nmglwx@163.com [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Zheng, Yu-Shan [Inner Mongolia Autonomous Region Product Quality Inspection Institute, Hohhot 010070 (China); Xin, Xiao-Dong; Guo, Feng; Cao, Xiao-Fang [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China)

    2015-06-15

    Two novel solid binary complexes of rare earth perchlorate with phenacyl p-tolyl sulfoxide were synthesized and characterized by elemental analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, {sup 1}HNMR and UV spectra. The results indicated that the composition of these complexes was REL{sub 7} (ClO{sub 4}){sub 3}·6H{sub 2}O (RE=Eu (III), Tb (III), L=C{sub 6}H{sub 5}COCH{sub 2}SOC{sub 6}H{sub 4}CH{sub 3}). The study on IR spectra and {sup 1}HNMR spectra revealed that phenacyl p-tolyl sulfoxide bonded with RE{sup 3+} ions by the oxygen atom in sulfinyl group. The emission spectra illustrated that both the Eu (III) and Tb (III) complexes displayed excellent luminescence in solid state, and The most intensive characteristic emission of the Eu(III) and Tb(III) complexes were 245,400 a.u. and 298,000 a.u. respectively. The slit with was 1 nm. By analysis luminescence and phosphorescence spectrum, it was found that the ligand had the advantage to absorb energy and transfer it to the Eu (III) and Tb (III) ions. The fluorescence lifetimes of the complexes were measured as well as the quantum yield of the Eu (III) complex.

  15. Synthesis and Crystal Structure of the Perchlorate Salt of Diprotonated 2,3-Di-2-pyridyl-5-nitroquinoxaline

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The diprotonated perchlorate salt of 2,3-di-2-pyridyl-5-nitroquinoxaline [C18H13N5O2](ClO4)2((CH3OH)((C2H5OH) has been synthesized and characterized by elemental analysis, IR and NMR spectra. X-ray diffraction analysis at room temperature indicates that the title compound (C21H23N5O12Cl2, Mr = 608.34) crystallizes in triclinic, space group P ī with a = 7.992(8), b = 12.82(1), c = 13.42(1) (A), α= 104.77(2), β = 97.84(2), γ = 95.48(2), V = 1305(2) (A)3, Z = 2, Dc = 1.549 g/cm3, F(000) = 628 and ((MoK() = 0.317 mm-1. The final R and wR factors are 0.0566 and 0.1016, respectively with 4325 independent reflections. The quinoxaline ring makes the dihedral angles of 44.2(2) and 33.9(5)( with two protonated pyridine rings whose dihedral angle is 48.1(6)(. The favored orientation of two protonated pyridine rings is that their N atoms are opposite to each other. There exist intra- and inter-molecular N-H…O hydrogen bonds and π…π interactions which stabilize the structure further.

  16. STIM1 is a Calcium Sensor Specialized for Digital Signaling

    OpenAIRE

    Bird, Gary S.; Hwang, Sung-Yong; Smyth, Jeremy T.; Fukushima, Miwako; Boyles, Rebecca R.; Putney, James W.

    2009-01-01

    When cells are activated by calcium-mobilizing agonists at low, physiological concentrations, the resulting calcium signals generally take the form of repetitive regenerative discharges of stored calcium, termed calcium oscillations [1]. These intracellular calcium oscillations have long fascinated biologists as representing a mode of digitized intracellular signaling. Recent work has highlighted the role of calcium influx as an essential component of calcium oscillations [2]. This influx occ...

  17. Fortification of all-purpose wheat-flour tortillas with calcium lactate, calcium carbonate, or calcium citrate is acceptable.

    Science.gov (United States)

    Romanchik-Cerpovicz, Joelle E; McKemie, Rebecca J

    2007-03-01

    Fortification helps provide adequate nutrients for individuals not meeting daily needs. Foods may be fortified with calcium to assist individuals with lactose intolerance and others preferring not to consume traditional forms of dairy. This study examined the quality of all-purpose wheat-flour tortillas fortified with calcium lactate, calcium carbonate, or calcium citrate. These tortillas were compared to similarly prepared nonfortified flour tortillas (control) and commercial nonfortified flour tortillas. Calcium-fortified tortillas contained 114 mg elemental calcium per standard serving (48 g tortilla), an 8.6-fold increase compared to nonfortified tortillas. Moisture contents and rollabilities of all tortillas were similar. Consumers (N=87) evaluated each tortilla in duplicate using a hedonic scale and reported liking the appearance, texture, flavor, aftertaste, and overall acceptability of all tortillas. However, the appearance of control tortillas was preferred over commercial tortillas (Ptortillas or those fortified with calcium carbonate was preferred over the control (Ptortillas, suggesting that appearance and aftertaste may not influence willingness to purchase. Overall, this study shows that fortification of flour tortillas with various forms of calcium is a feasible alternative calcium source. PMID:17324671

  18. Binding of calcium and carbonate to polyacrylates.

    Science.gov (United States)

    Tribello, Gareth A; Liew, CheeChin; Parrinello, Michele

    2009-05-21

    Polyacrylate molecules can be used to slow the growth of calcium carbonate. However, little is known about the mechanism by which the molecules impede the growth rate. A recent computational study (Bulo et al. Macromolecules 2007, 40, 3437) used metadynamics to investigate the binding of calcium to polyacrylate chains and has thrown some light on the coiling and precipitation of these polymers. We extend these simulations to examine the binding of calcium and carbonate to polyacrylate chains. We show that calcium complexed with both carbonate and polyacrylate is a very stable species. The free energies of calcium-carbonate-polyacrylate complexes, with different polymer configurations, are calculated, and differences in the free energy of the binding of carbonate are shown to be due to differences in the amount of steric hindrance about the calcium, which prevents the approach of the carbonate ion. PMID:19400592

  19. Biphasic calcium phosphate in periapical surgery

    OpenAIRE

    Suneelkumar, Chinni; Datta, Krithika; Manali R Srinivasan; Kumar, Sampath T

    2008-01-01

    Calcium phosphate ceramics like hydroxyapatite and β -tricalcium phosphate (β -TCP) possess mineral composition that closely resembles that of the bone. They can be good bone substitutes due to their excellent biocompatibility. Biphasic calcium phosphate is a bone substitute which is a mixture of hydroxyapatite and β -tricalcium phosphate in fixed ratios. Studies have demonstrated the osteoconductive potential of this composition. This paper highlights the clinical use of biphasic calcium pho...

  20. Gravity, Calcium, And Bone: Update, 1989

    Science.gov (United States)

    Arnaud, Sara B.; Morey-Holton, Emily

    1992-01-01

    Report reviews short-term flight and ground-based experiments on effects of 1 g and 0 g on skeletal adaptation, calcium metabolism, and growth processes. Results indicate two principal components of calcium metabolism-calcium endocrine system and bone - respond within days to changes in orientation of body in gravitation and to weightlessness. Effects of spaceflight or bed rest on biomechanics of bones more severe than on total body bone mass.

  1. Gravity, calcium, and bone - Update, 1989

    Science.gov (United States)

    Arnaud, Sara B.; Morey-Holton, Emily

    1990-01-01

    Recent results obtained on skeletal adaptation, calcium metabolism, and bone browth during short-term flights and ground simulated-microgravity experiments are presented. Results demonstrate that two principal components of calcium metabolism respond within days to changes in body position and to weightlessness: the calcium endocrine system and bone characteristics. Furthermore, results of recent studies imply that bone biomechanics are more severely affected by spaceflight exposures than is the bone mass.

  2. Familial hypocalciuric hypercalcemia and calcium sensing receptor

    DEFF Research Database (Denmark)

    Mrgan, Monija; Nielsen, Sanne; Brixen, Kim

    2014-01-01

    Familial hypocalciuric hypercalcemia (FHH) is a lifelong, benign autosomal dominant disease characterized by hypercalcemia, normal to increased parathyroid hormone level, and a relatively low renal calcium excretion. Inactivation of the calcium-sensing receptor in heterozygous patients results in...... FHH, while in homozygous patients as well as in compound heterozygous or dominant negative heterozygous patients, it may result in neonatal severe hyperparathyroidism (NSHPT). Parathyroid surgery is not indicated in FHH and does not lower plasma calcium unless total parathyroidectomy is performed, in...

  3. Overbased Calcium sulfonate Detergent Technology Overview

    Institute of Scientific and Technical Information of China (English)

    MA Qing-gao; MUIR Ronald J.

    2009-01-01

    Overbased calcium sulfonate is used widely as detergent in automotive and marine lubricants, as well as various industrial oil applications. In this paper, the process to produce overbased calcium sulfonate is overviewed. The sulfonate structure and molecular weight and its molecular weight distribution, the enclosed calcium carbonate nanoparticle size and crystalline structure, properties of the carrier oil, all influence its properties, such as stability, viscosity, and detergency of the system.

  4. Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Jepson, B.E.; Shockey, G.C.

    1984-01-01

    The enrichment of calcium isotopes has been observed in ion-exchange chromatography with an aqueous phase of calcium hydroxide and a solid phase of sulfonic acid resin. The band front was exceedingly sharp as a result of the acid-base reaction occuring at the front of the band. Single-stage separation coefficients were found to be epsilon(/sup 44/Ca//sup 40/Ca) = 11 x 10 /sup -4/ and epsilon(/sup 48/Ca//sup 40/Ca) = 18 x 10/sup -4/. The maximum column separation factors achieved were 1.05 for calcium-44 and 1.09 for calcium-48 with the heavy isotopes enriching in the fluid phase. The calcium isotope effect between fully hydrated aqueous calcium ions and undissociated aqueous calcium hydroxide was estimated. For the calcium-44/40 isotope pair the separation coefficient was 13 x 10/sup -4/. 20 references, 2 figures.

  5. Calcium carboorthovanadate - a new compound with the apa

    International Nuclear Information System (INIS)

    Data on calcium carboorthovanadate, Ca10(VO4)6CO3, a new compound with an appatite structure based on calcium orthovanadate, are reported. The synthesis has been conducted in a stoichiometric mixture of finely ground calcium carbonate and calcium orthovanadate. It is found that calcium carboorthovanadate belongs to the hexagonal syngony and has an apatite structure. An analysis of the infrared spectra of initial compounds and calcium carboorthovanadate confirmed the presence of carbonate (CO3)2- and orthovanadate (VO4)3 groupings in the latter. On heating in air, beginning with 450 deg C calcium carboorthovanadate decomposes at a slow rate into calcium oxide, calcium orthovanadate, and carbon dioxide

  6. Calcium supplements: do they help or harm?

    Science.gov (United States)

    Manson, Joann E; Bassuk, Shari S

    2014-01-01

    Current recommendations for calcium intake call for 1,000 mg per day for women ages 19-50 and 1,200 mg per day for women over age 50 to ensure bone health. Given recent concerns that calcium supplements may raise risk for cardiovascular disease and kidney stones, women should aim to meet this recommendation primarily by eating a calcium-rich diet and taking calcium supplements only if needed to reach the RDA goal (often only approximately 500 mg per day in supplements is required). PMID:23880796

  7. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

    Thomsen, Louiza Bohn; Jörntell, Henrik; Midtgaard, Jens

    2010-01-01

    appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than 1 s...... affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be...

  8. Peroxisome is a reservoir of intracellular calcium.

    Science.gov (United States)

    Raychaudhury, Bikramjit; Gupta, Shreedhara; Banerjee, Shouvik; Datta, Salil C

    2006-07-01

    We have examined fura 2-loaded purified peroxisomes under confocal microscope to prove that this mammalian organelle is a store of intracellular calcium pool. Presence of calcium channel and vanadate sensitive Ca(2+)-ATPase in the purified peroxisomal membrane has been demonstrated. We have further observed that machineries to maintain calcium pool in this mammalian organelle are impaired during infection caused by Leishmania donovani. Results reveal that peroxisomes have a merit to play a significant role in the metabolism of intracellular calcium. PMID:16713100

  9. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K

    2014-01-01

    receptor. Endosomal acidification and calcium efflux lead to the essential ligand-receptor affinity switch and separation. Recent data, including crystal structures of receptor-ligand complexes, now reveal how calcium, in different types of domain scaffolds, functions in a common way as a removable...... 'lynchpin' that stabilizes favorable positioning of ligand-attractive receptor residues. In addition to explaining how calcium depletion can cause ligand-receptor dissociation, the new data add further insight into how acidification contributes to dissociation through structural changes that affect the...... receptor calcium sites....

  10. Calcium wave of Brain Astrocytes

    Science.gov (United States)

    Cornell Bell, A. H.

    1997-03-01

    Time lapse confocal scanning laser microscopy was used to study hippocampal astrocyte cultures loaded with a calcium indicator, Fluo3-AM (4 uM). kThe neurotransmitter kainate (100uM) overwhelms the Na+-buffering capacity of astrocytes within 100 sec resulting in reversal of the Na+/Ca2+ exchanger. This results in a subcellular site where Ca2+ entering the cytoplasm contributes to a long-distance Ca2+ wave which travels at 20 um/sec without decrement. Image analysis has shown calcium waves not only at a high Kainate dose, but also at a low Kainate dose, e.g. 10uM. These are, however, shortlived and burried in an extremely noisy background and only detectable by analyzing the calcium waves images for spatio-temporal coherence. As the kainate dose increases, more large scale coherent structures with visible geometric features (spiral waves and target waves) can be observed. Multiple spiral waves are produced when the Kainate dose increases to 100 uM. These waves travel at a constant velocity across entire microscope fields for long time periods (>30 mins). Na+ channels have no effect on the Kainate wave. Voltage-gated Ca2+ channels are not involved and Ca2+ enters through reversal of the exchanger. Ca2+ release from stores does not contribute to the kainate wave. Removal of Na+ or Ca2+ from outside and the specific Na+/Ca2+ exchange inhibitor benzamil (10 uM) inhibit the kainate wave. A functional antibody to alpha6-Integrin which is localized to membrane regions between cells inhibits the spread of the kainate wave in a dose and time-dependent manner. Fluorescence Recovery after Photobleach (FRAP) techniques indicate that gap junctions remain open between cells. This would imply that Ca2+ or IP3 need not pass through the gap junction, but reversal of the exchanger would propel the Ca2+ wave at the cell surface.

  11. Calcium and magnesium silicate hydrates

    International Nuclear Information System (INIS)

    Deep geological disposals are planed to discard long-lived intermediate-level and high-level radioactive wastes. Clay-based geological barriers are expected to limit the ingress of groundwater and to reduce the mobility of radioelements. In the interaction zone between the cement and the clay based material alteration can occur. Magnesium silicate hydrates (M-S-H) have been observed due to the reaction of magnesium sulfate containing groundwater with cements or in the interaction zone between low-pH type cement and clays. M-S-H samples synthesized in the laboratory showed that M-S-H has a variable composition within 0.7 ≤ Mg/Si ≤ 1.5. TEM/EDS analyses show an homogeneous gel with no defined structure. IR and 29Si NMR data reveal a higher polymerization degree of the silica network in M-S-H compared to calcium silicate hydrates (C-S-H). The presence of mainly Q3 silicate tetrahedrons in M-S-H indicates a sheet like or a triple-chain silica structure while C-S-H is characterised by single chain-structure. The clear difference in the silica structure and the larger ionic radius of Ca2+ (1.1 Angstrom) compared to Mg2+ (0.8 Angstrom) make the formation of an extended solid solution between M-S-H and C-S-H gel improbable. In fact, the analyses of synthetic samples containing both magnesium and calcium in various ratios indicate the formation of separate M-S-H and C-S-H gels with no or very little uptake of magnesium in CS-H or calcium in M-S-H

  12. Calcium Absorption from Fortified Ice Cream Formulations Compared with Calcium Absorption from Milk

    OpenAIRE

    van der Hee, Regine M.; Miret, Silvia; Slettenaar, Marieke; Duchateau, Guus S.M.J.E.; Rietveld, Anton G.; Wilkinson, Joy E.; Quail, Patricia J.; Berry, Mark J.; Dainty, Jack R.; Teucher, Birgit; Fairweather-Tait, Susan J

    2009-01-01

    Objective Optimal bone mass in early adulthood is achieved through appropriate diet and lifestyle, thereby protecting against osteoporosis and risk of bone fracture in later life. Calcium and vitamin D are essential to build adequate bones, but calcium intakes of many population groups do not meet dietary reference values. In addition, changes in dietary patterns are exacerbating the problem, thereby emphasizing the important role of calcium-rich food products. We have designed a calcium-fort...

  13. Association of Urinary Calcium Excretion with Serum Calcium and Vitamin D Levels

    OpenAIRE

    A Rathod; Bonny, O; Guessous, I; Suter, P M; Conen, D; Erne, P; Binet, I; Gabutti, L; Gallino, A; Muggli, F; Hayoz, D; Pechere-Bertschi, A; Paccaud, F.; Burnier, M.; Bochud, M

    2015-01-01

    BACKGROUND AND OBJECTIVES: Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS: Multivariable linear regression was used to explore factors associated with square root-transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dep...

  14. Drosophila mushroom body Kenyon cells generate spontaneous calcium transients mediated by PLTX-sensitive calcium channels.

    OpenAIRE

    Jiang, Shaojuan Amy; Campusano, Jorge M.; Su, Hailing; O'Dowd, Diane K.

    2005-01-01

    Spontaneous calcium oscillations in mushroom bodies of late stage pupal and adult Drosophila brains have been implicated in memory consolidation during olfactory associative learning. This study explores the cellular mechanisms regulating calcium dynamics in Kenyon cells, principal neurons in mushroom bodies. Fura-2 imaging shows that Kenyon cells cultured from late stage Drosophila pupae generate spontaneous calcium transients in a cell autonomous fashion, at a frequency similar to calcium o...

  15. The Electronic Structure of Calcium

    DEFF Research Database (Denmark)

    Jan, J.-P.; Skriver, Hans Lomholt

    1981-01-01

    The electronic structure of calcium under pressure is re-examined by means of self-consistent energy band calculations based on the local density approximation and using the linear muffin-tin orbitals (LMTO) method with corrections to the atomic sphere approximation included. At zero pressure.......149 Ryd, respectively, relative to the s band, give the best possible agreement. Under increasing pressure the s and p electrons are found to transfer into the d band, and Ca undergoes metal-semimetal-metal electronic transitions. Calculations of the bandstructure and the electronic pressure, including...

  16. Physicochemical investigation of calcium bromtechnetate

    International Nuclear Information System (INIS)

    Calcium hexabromotechnetate is extracted for the first time and its composition corresponding to the CaTcBr6 formula is determined. Using the thermal analysis method the anhydrous salt stability boundaries are found. The X-ray phase analysis has shown the compound to be isostructural with (NH4)2TcI6 and has a rhombic b.c.c. crystal lattice with the following parameters: a=10.39+-0.01, b=7.34+-0.01 and c=7.45+-0.001A. At 380-420 deg C CaTcBr6 decomposes to Tc, CaBr2 and Br

  17. Calcium Imaging Perspectives in Plants

    Directory of Open Access Journals (Sweden)

    Chidananda Nagamangala Kanchiswamy

    2014-03-01

    Full Text Available The calcium ion (Ca2+ is a versatile intracellular messenger. It provides dynamic regulation of a vast array of gene transcriptions, protein kinases, transcription factors and other complex downstream signaling cascades. For the past six decades, intracellular Ca2+ concentration has been significantly studied and still many studies are under way. Our understanding of Ca2+ signaling and the corresponding physiological phenomenon is growing exponentially. Here we focus on the improvements made in the development of probes used for Ca2+ imaging and expanding the application of Ca2+ imaging in plant science research.

  18. Barium calcium hydroxyapatite solid solutions

    International Nuclear Information System (INIS)

    The replacement of calcium by barium in the hydroxyapatite structure by solid-state reaction at different temperatures and by precipitation from an aqueous system has been investigated by X-ray diffraction and i.r. absorption analyses. The products obtained by solid-state reaction at 1200 deg C are solid solutions over the range of barium concentration 60 to 100 atom %. The lattice dimensions and the i.r. frequencies of the solid solutions vary linearly with the atom % of barium. Only small amounts of barium can be incorporated in hydroxyapatite by precipitation from the aqueous system. (author)

  19. Calcium

    Science.gov (United States)

    ... for lunch; and beans, salsa, taco sauce, and cheese for dinner. Create mini-pizzas by topping whole-wheat English muffins or bagels with pizza sauce and low-fat mozzarella or soy cheese. Try whole-grain crackers with low-fat cheese ...

  20. Calcium

    Science.gov (United States)

    ... eliminates in urine, feces, and sweat. These include consumption of alcohol- and caffeine-containing beverages as well as intake ... and older 2,000 mg Pregnant and breastfeeding teens 3,000 mg Pregnant and breastfeeding adults 2, ...

  1. 2,4,6-Trimethylpyridinium perchlorate: Polar properties and correlations with molecular structure of organic-inorganic hybrid crystal

    International Nuclear Information System (INIS)

    [(CH3)3C5H2NH][ClO4] has been synthesized and characterized by X-ray (at 344, 245, 180 and 115 K), calorimetric, dilatometric, dielectric and pyroelectric measurements. At room temperature the crystal structure is polar, space group Pmn21. It consists of discrete disordered [ClO4]- anions and ordered trimethylpyridinium cations giving the 3D network of hydrogen bonds. The compound reveals a rich polymorphism in the solid state. It undergoes four solid-solid phase transitions: from phases I to II at 356/327 K (heating/cooling), II→III at 346/326, III→IV at 226 K and IV→V at 182/170 K. [(CH3)3C5H2NH][ClO4] reveals a strong pyroelectric response over a wide temperature region (phases III, IV and V) with the spontaneous polarization changes (ΔPs) of the order of 1.5-8x10-3C/m2. The spontaneous polarization is irreversible over all the polar phases, however, the magnitude of the ΔPs in the vicinity of the phase transitions is characteristic of compounds with the ferroelectric order. The molecular mechanism of the successive phases transitions in the studied crystal is proposed. - A novel organic-inorganic hybrid material, simple ionic salt: 2,4,6-trimethylpyridinium perchlorate, [(CH3)3C5H2NH][ClO4] has been synthesized. In this paper we report singlecrystal X-ray, powder X-ray, calorimetric, dilatometric, dielectric and pyroelectric studies of this compound over a wide temperature range. A possible mechanism of the structural phase transitions in [(CH3)3C5H2NH][ClO4] is discussed with particular attention focused on unusually strong pyroelectric properties.

  2. Atacama perchlorate as an agricultural contaminant in groundwater: Isotopic and chronologic evidence from Long Island, New York

    Science.gov (United States)

    Böhlke, J.K.; Hatzinger, P.B.; Sturchio, N.C.; Gu, B.; Abbene, I.; Mroczkowski, S.J.

    2009-01-01

    Perchlorate (ClO4-) is a common groundwater constituent with both synthetic and natural sources. A potentially important source of ClO4- is past agricultural application of ClO4--bearing natural NO3- fertilizer imported from the Atacama Desert, Chile, but evidence for this hasbeenlargely circumstantial. Here we report ClO4- stable isotope data (??37Cl, ??18O, and ??17O), along with other supporting chemical and isotopic environmental tracer data, to document groundwater ClO4- contamination sources and history in parts of Long Island, New York. Sampled groundwaters were oxic and ClO4- apparently was not affected by biodegradation within the aquifers. Synthetic ClO4- was indicated by the isotopic method in groundwater near a fireworks disposal site at a former missile base. Atacama ClO4- was indicated in agricultural and urbanizing areas in groundwaters with apparent ages >20 years. In an agricultural area, ClO4- concentrations and ClO4-/NO3- ratios increased withgroundwaterage, possiblybecauseof decreasing application rates of Atacama NO3- fertilizers and/or decreasing ClO4- concentrations in Atacama NO 3- fertilizers in recent years. Because ClO 4-/NO3- ratios of Atacama NO 3- fertilizers imported in the past (???2 ?? 10-3 mol mol-1) were much higher than the ClO 4-/NO3- ratio of recommended drinking-water limits (7 ?? 10-5 mol mol-1 in New York), ClO4- could exceed drinkingwater limits even where NO3- does not, and where Atacama NO3- was only a minor source of N. Groundwater ClO4- with distinctive isotopic composition was a sensitive indicator of past Atacama NO3- fertilizer use on Long Island and may be common in other areas that received NO3- fertilizers from the late 19th century through the 20th century. ?? 2009 American Chemical Society.

  3. Preparation and characterization of novel solid polymer blend electrolytes based on poly (vinyl pyrrolidone) with various concentrations of lithium perchlorate

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The maximum ionic conductivity value was found to be 0.2307 × 10−5 S cm−1 for PEO(90 wt%)/PVP(10 wt%)/LiClO4(8 wt%) based electrolyte at room temperature. • The structural and functional groups were studied by XRD and FTIR. • Both direct and indirect optical band gap values were evaluated from UV–vis analysis. • The change in viscosity of the polymer electrolytes was studied by photoluminescence spectra. - Abstract: A series of conducting novel solid polymer blend electrolytes (SPE) based on the fixed ratio of poly (ethylene oxide)/poly (vinyl pyrrolidone) (PEO/PVP) and various concentrations of salt lithium perchlorate (LiClO4) were prepared by solvent casting technique. Structural and complex formation of the prepared electrolytes was confirmed by X-ray diffraction and FTIR analyses. The maximum ionic conductivity value was found to be 0.2307 × 10−5 S cm−1 for 8 wt% of LiClO4 based system at ambient temperature. Thermal stability of the present system was studied by thermo gravimetric/differential thermal analysis (TG/DTA). Surface morphology of the sample having maximum ionic conductivity was studied by atomic force microscope (AFM). Optical properties like direct and indirect band gaps were investigated by UV–vis analysis. The change in viscosity of the polymer complexes were also identified using photoluminescence emission spectra. PEO(90)/PVP(10)/LiClO4(8) has the highest conductivity which is supported by the lowest optical band gap and lowest intensity in photoluminescence spectroscopy near 400–450 nm

  4. Synthesis of porous sheet-like Co3O4 microstructure by precipitation method and its potential applications in the thermal decomposition of ammonium perchlorate

    International Nuclear Information System (INIS)

    Porous sheet-like cobalt oxide (Co3O4) were successfully synthesized by precipitation method combined with calcination of cobalt hydroxide precursors. The structure, morphology and porosity properties of the products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption–desorption measurement. The as-prepared sheet-like microstructures were approximately 2–3 μm in average diameter, and the morphology of the cobalt hydroxide precursors was retained after the calcination process. However, it appeared a large number of uniform pores in the sheets after calcination. In order to calculate the potential catalytic activity, the thermal decomposition of ammonium perchlorate (AP) has been analyzed, in which cobalt oxide played a role of an additive and the porous sheet-like Co3O4 microstructures exhibited high catalytic performance and considerable decrease in the thermal decomposition temperature of AP. Moreover, a formation mechanism for the sheet-like microstructures has been discussed. - Graphical abstract: Porous sheet-like Co3O4 were synthesized by facile precipitation method combined with calcination of β-Co(OH)2 precursors. Thermogravimetric–differential scanning calorimetric analysis indicates potential catalytic activity in the thermal decomposition of ammonium perchlorate. Highlights: ► Synthesis of sheet-like β-Co(OH)2 precursors by precipitation method. ► Porous sheet-like Co3O4 were obtained by calcining β-Co(OH)2 precursors. ► The possible formation mechanism of porous sheet-like Co3O4 has been discussed. ► Porous sheet-like Co3O4 decrease the thermal decomposition temperature of ammonium perchlorate.

  5. Calcium and Vitamin D: Important at Every Age

    Science.gov (United States)

    ... supported by your browser. Home Bone Basics Nutrition Calcium and Vitamin D: Important at Every Age Publication ... Osteoporosis Program For Your Information The Role of Calcium Calcium is needed for our heart, muscles, and ...

  6. Clinical validation of dialysable calcium in relation to other methods of serum calcium measurement.

    OpenAIRE

    Prince, R. L.; Langton, S R

    1985-01-01

    Dialysable calcium (CaD) values were measured by a simple technique not interfered with by protein bound calcium and validation attempted by comparison with concentrations of ionised calcium (CaI) and clinical categorisation. CaD values were also compared with total calcium (CaT) and albumin adjusted calcium (CaA) concentrations. The normal ranges for CaD, CaT, CaA, and CaI were calculated from the results in healthy blood donors. In 50 normal subjects CaD was more highly correlated with CaI ...

  7. The perchlorate anion is more effective than the trifluoroacetate anion as an ion-pairing reagent for reversed-phase chromatography of peptides

    OpenAIRE

    Shibue, M.; Mant, C.T.; Hodges, R.S.

    2005-01-01

    The addition of salts, specifically sodium perchlorate (NaClO4), to mobile phases at acidic pH as ion-pairing reagents for reversed-phase high-performance liquid chromatography (RP-HPLC) has been generally overlooked. To demonstrate the potential of NaClO4 as an effective anionic ion-pairing reagent, we applied RP-HPLC in the presence of 0–100 mM sodium chloride (NaCl), sodium trifluoroacetate (NaTFA) or NaClO4 to two mixtures of synthetic 18-residue peptides: a mixture of peptides with the s...

  8. Combustion of Organic Molecules by the Thermal Decomposition of Perchlorate Salts: Implications for Organics at the Mars Phoenix Scout Landing Site

    Science.gov (United States)

    Ming, D.W.; Morris, R.V.; Niles, B.; Lauer, H.V.; Archer, P.D.; Sutter, B.; Boynton, W.V.; Golden, D.C.

    2009-01-01

    The Mars 2007 Phoenix Scout Mission successfully landed on May 25, 2008 and operated on the northern plains of Mars for 150 sols. The primary mission objective was to study the history of water and evaluate the potential for past and present habitability in Martian arctic ice-rich soil [1]. Phoenix landed near 68 N latitude on polygonal terrain created by ice layers that are a few centimeters under loose soil materials. The Phoenix Mission is assessing the potential for habitability by searching for organic molecules in the ice or icy soils at the landing site. Organic molecules are necessary building blocks for life, although their presence in the ice or soil does not indicate life itself. Phoenix searched for organic molecules by heating soil/ice samples in the Thermal and Evolved-Gas Analyzer (TEGA, [2]). TEGA consists of 8 differential scanning calorimeter (DSC) ovens integrated with a magnetic-sector mass spectrometer with a mass range of 2-140 daltons [2]. Endothermic and exothermic reactions are recorded by the TEGA DSC as samples are heated from ambient to 1000 C. Evolved gases, including any organic molecules and their fragments, are simultaneously measured by the mass spectrometer during heating. Phoenix TEGA data are still under analysis; however, no organic fragments have been identified to date in the evolved gas analysis (EGA). The MECA Wet Chemistry Lab (WCL) discovered a perchlorate salt in the Phoenix soils and a mass 32 peak evolved between 325 and 625 C for one surface sample dubbed Baby Bear [3]. The mass 32 peak is attributed to evolved O2 generated during the thermal decomposition of the perchlorate salt. Perchlorates are very strong oxidizers when heated, so it is possible that organic fragments evolved in the temperature range of 300-600 C were combusted by the O2 released during the thermal decomposition of the perchlorate salt. The byproduct of the combustion of organic molecules is CO2. There is a prominent release of CO2 between 200

  9. Electrophysical behavior of ion-conductive organic-inorganic polymer system based on aliphatic epoxy resin and salt of lithium perchlorate

    OpenAIRE

    Matkovska, Liubov; Iurzhenko, Maksym; Mamunya, Yevgen; Matkovska, Olga; Demchenko, Valeriy; Lebedev, Eugene; Boiteux, Gisele; Serghei, Anatoli

    2014-01-01

    Abstract In the present work, ion-conductive hybrid organic-inorganic polymers based on epoxy oligomer of diglycide aliphatic ester of polyethylene glycol (DEG) and lithium perchlorate (LiClO4) were synthesized. The effect of LiClO4 content on the electrophysical properties of epoxy polymers has been studied by differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS). The effect of LiClO4 content on the structure has been studied by wide-angle X-ray scattering (WAXS...

  10. Crystal structure of trans-bis(ethane-1,2-diamine-κ2N,N′)bis(thiocyanato-κN)chromium(III) perchlorate from synchrotron data

    OpenAIRE

    Dohyun Moon; Jong-Ha Choi

    2015-01-01

    The structure of the title compound, [Cr(NCS)2(C2H8N2)2]ClO4, has been determined from synchroton data. The asymmetric unit consists of one half of a centrosymmetric CrIII complex cation and half of a perchlorate anion with the Cl atom on a twofold rotation axis. The CrIII ion is coordinated by the four N atoms of two ethane-1,2-diamine (en) ligands in the equatorial plane and two N-bound thiocyanate (NCS−) anions in a trans-axial arrangement, displaying a slightly distorted octahedral geomet...

  11. cis-Aquabis(2,2'-bipyridine-κ2N,N')-fluoridochromium(III) bis(perchlorate) dihydrate

    DEFF Research Database (Denmark)

    Birk, Torben; Bendix, Jesper

    2010-01-01

    The title mixed aqua-fluoride complex, [CrF(C(10)H(8)N(2))(2)(H(2)O)](ClO(4))(2)·2H(2)O, has been synthesized by aqua-tion of the corresponding difluoride complex using lanthan-ide(III) ions as F(-) acceptors. The complex crystallizes with a Cr(III) ion at the center of a distorted octa......-hedral coordination polyhedron with a cis arrangement of ligands. The crystal packing shows a hydrogen-bonding pattern involving water mol-ecules, the coordinated F atom and the perchlorate anions....

  12. An Intracellular Calcium Oscillations Model Including Mitochondrial Calcium Cycling

    Institute of Scientific and Technical Information of China (English)

    SHI Xiao-Min; LIU Zeng-Rong

    2005-01-01

    @@ Calcium is a ubiquitous second messenger. Mitochondria contributes significantly to intracellular Ca2+ dynamics.The experiment of Kaftan et al. [J. Biol. Chem. 275(2000) 25465] demonstrated that inhibiting mitochondrial Ca2+ uptake can reduce the frequency of cytosolic Ca2+ concentration oscillations of gonadotropes. By considering the mitochondrial Ca2+ cycling we develop a three-variable model of intracellular Ca2+ oscillations based on the models of Atri et al. [Biophys. J. 65 (1993) 1727] and Falcke et al. [Biophys. J. 77 (1999) 37]. The model reproduces the fact that mitochondrial Ca2+ cycling increases the frequency of cytosolic Ca2+ oscillations, which accords with Kaftan's results. Moreover the model predicts that when the mitochondria overload with Ca2+, the cytosolic Ca2+ oscillations vanish, which may trigger apoptosis.

  13. Bone Up on the Need for Calcium.

    Science.gov (United States)

    Mann, Peggy

    1987-01-01

    Most grade-schoolers drink milk at each meal, but teens, especially girls, often switch to carbonated soda at mealtime just as they should be building up their bone bank of calcium. Why calcium is important and how to get enough of it are covered. (MT)

  14. 21 CFR 182.8217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.8217 Section 182.8217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  15. Calcium, snails, and birds: a case study

    Directory of Open Access Journals (Sweden)

    R. Mänd

    2000-10-01

    Full Text Available Recent studies have shown that wild birds breeding in acidified areas have difficulties with obtaining sufficient calcium for their eggshells, and that the cause of it is the shortage of land snails. Many birds have to search for Ca-rich snail shells on a daily basis during egg production. Molluscs depend on litter calcium, which has decreased due to acidification of the environment. Calcium limitation may be a widespread phenomenon also in non-acidified, naturally Ca-poor areas. The problem is that while in the latter areas the time for development of specific adaptations may have been sufficient, then in acidified areas, on the contrary, calcium shortage is a recent phenomenon. Therefore, since the extent of calcium limitation in non-acidified areas is hard to derive from observational data, experimental approach is needed. We provide experimental evidence that specific calcium deficit does affect reproductive traits also in the birds breeding in naturally base-poor habitats. Our study was conducted in a heterogeneous woodland area in Estonia containing deciduous forest patches as well as base-poor pine forest with low snail abundance. Ca supplementation, using snail shell and chicken eggshell fragments, was carried out for pied flycatchers and great tits. Extra calcium affected positively several reproductive traits like egg volume and eggshell thickness, start of breeding, and fledglings’ parameters. The negative relationship between calcium availability and lay-date suggests that birds adjust their breeding tactics to conditions of Ca deficiency, for example, by postponing laying.

  16. Calcium Free Asbestos for Fuel Cells

    Science.gov (United States)

    Snitzer, B. A.

    1983-01-01

    Organic-acid salt removes unwanted calcium without weakening asbestos. Asbestos mixed with disodium ethylene diamine tetraacetic acid (disodium EDTA) in water and agitated for 2 hours. After disodium EDTA solution is drained away, asbestos contains only 0.02 to 0.1 percent calcium. Fiber structure of asbestos unaffected.

  17. Stochastic models of intracellular calcium signals

    International Nuclear Information System (INIS)

    Cellular signaling operates in a noisy environment shaped by low molecular concentrations and cellular heterogeneity. For calcium release through intracellular channels–one of the most important cellular signaling mechanisms–feedback by liberated calcium endows fluctuations with critical functions in signal generation and formation. In this review it is first described, under which general conditions the environment makes stochasticity relevant, and which conditions allow approximating or deterministic equations. This analysis provides a framework, in which one can deduce an efficient hybrid description combining stochastic and deterministic evolution laws. Within the hybrid approach, Markov chains model gating of channels, while the concentrations of calcium and calcium binding molecules (buffers) are described by reaction–diffusion equations. The article further focuses on the spatial representation of subcellular calcium domains related to intracellular calcium channels. It presents analysis for single channels and clusters of channels and reviews the effects of buffers on the calcium release. For clustered channels, we discuss the application and validity of coarse-graining as well as approaches based on continuous gating variables (Fokker–Planck and chemical Langevin equations). Comparison with recent experiments substantiates the stochastic and spatial approach, identifies minimal requirements for a realistic modeling, and facilitates an understanding of collective channel behavior. At the end of the review, implications of stochastic and local modeling for the generation and properties of cell-wide release and the integration of calcium dynamics into cellular signaling models are discussed

  18. Stochastic Kinetics of Intracellular Calcium Oscillations

    Institute of Scientific and Technical Information of China (English)

    陈昌胜; 曾仁端

    2003-01-01

    A stochastic model of intracellular calcium oscillations is put forward by taking into account the random opening-closing of Ca2+ channels in endoplasmic reticulum (ER) membrane. The numerical results of the stochastic model show simple and complex calcium oscillations, which accord with the experiment results.

  19. 21 CFR 172.410 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Anticaking Agents § 172.410 Calcium...

  20. Engineering calcium oxalate crystal formation in Arabidopsis

    Science.gov (United States)

    Many plants accumulate crystals of calcium oxalate. Just how these crystals form remains unknown. To gain insight into the mechanisms regulating calcium oxalate crystal formation, a crystal engineering approach was initiated utilizing the non-crystal accumulating plant, Arabidopsis. The success of t...

  1. Stochastic models of intracellular calcium signals

    Energy Technology Data Exchange (ETDEWEB)

    Rüdiger, Sten, E-mail: sten.ruediger@physik.hu-berlin.de

    2014-01-10

    Cellular signaling operates in a noisy environment shaped by low molecular concentrations and cellular heterogeneity. For calcium release through intracellular channels–one of the most important cellular signaling mechanisms–feedback by liberated calcium endows fluctuations with critical functions in signal generation and formation. In this review it is first described, under which general conditions the environment makes stochasticity relevant, and which conditions allow approximating or deterministic equations. This analysis provides a framework, in which one can deduce an efficient hybrid description combining stochastic and deterministic evolution laws. Within the hybrid approach, Markov chains model gating of channels, while the concentrations of calcium and calcium binding molecules (buffers) are described by reaction–diffusion equations. The article further focuses on the spatial representation of subcellular calcium domains related to intracellular calcium channels. It presents analysis for single channels and clusters of channels and reviews the effects of buffers on the calcium release. For clustered channels, we discuss the application and validity of coarse-graining as well as approaches based on continuous gating variables (Fokker–Planck and chemical Langevin equations). Comparison with recent experiments substantiates the stochastic and spatial approach, identifies minimal requirements for a realistic modeling, and facilitates an understanding of collective channel behavior. At the end of the review, implications of stochastic and local modeling for the generation and properties of cell-wide release and the integration of calcium dynamics into cellular signaling models are discussed.

  2. Particularities of thermal expansion of calcium vanadates

    International Nuclear Information System (INIS)

    Temperature dependence of unit cell parameters of calcium vanadates Ca(VO3)2, Ca2V2O7 and Ca3(VO4)2 is studied. It is shown that lattice parameters of meta- and pyrovanadates change monotonously. Lattice parameters of calcium orthovanadate change sharply and unmonotonously at 400-500 deg C

  3. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  4. ALG-2, a multifunctional calcium binding protein?

    DEFF Research Database (Denmark)

    Tarabykina, Svetlana; Mollerup, Jens; Winding Gojkovic, P.;

    2004-01-01

    ALG-2 was originally discovered as a pro-apoptotic protein in a genetic screen. Due to its ability to bind calcium with high affinity it was postulated to provide a link between the known effect of calcium in programmed cell death and the molecular death execution machinery. This review article...

  5. Calcium Forms,Subcelluar Distribution and Ultrastructure of Pulp Cells as Influenced by Calcium Deficiency in Apple (Malus pumila) Fruits

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-hui; ZHOU Wei

    2004-01-01

    Calcium in Red Fuji and Starkrimson apples during storage were fractionated by sequent extracting. Localization and distribution of calcium and influence of calcium nutrition on cell ultrastructure were observed by transmission electron microscopy combined with in situ precipitation of calcium with an improved method of potassium pyroantimonate technique. Results indicated that spraying calcium solution on surface of young fruits increased contents of calcium in all forms. During storage, contents of soluble calcium and pectic calcium declined and thosein calcium phosphate, calcium oxalate and calcium silicate increased. Calcium contents of Red Fuji in all forms were higher than those of Starkrimson, indicating that calcium accumulating capability of Red Fuji fruits preceded that of Starkrimson. Under transmission electron microscopy, calcium antimonite precipitates (CaAP) was mainly distributed in cell wall, tonoplast, nuclear membrane and nucleoplasm,much more CaAP deposited in vacuole. Calcium deficiency during storage leads to decrease of CaAP in locations mentioned above, disappearance of compartmentation, and entrance of CaAP to cytoplasm. Transformation from soluble calcium and pectic calcium to calcium phosphate,oxalate and damages of biomembranes structuraly and functionally resulted from calcium deficiency during storage were the crucial causation of physiological disorder.

  6. Application of Calcium Phosphate Materials in Dentistry

    Directory of Open Access Journals (Sweden)

    Jabr S. Al-Sanabani

    2013-01-01

    Full Text Available Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1 application of calcium phosphate into various fields in dentistry; (2 improving mechanical properties of calcium phosphate; (3 biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields.

  7. Diagnosis and assessment of skeletal related disease using calcium 41

    Science.gov (United States)

    Hillegonds, Darren J.; Vogel, John S.; Fitzgerald, Robert L.; Deftos, Leonard J.; Herold, David; Burton, Douglas W.

    2012-05-15

    A method of determining calcium metabolism in a patient comprises the steps of administering radioactive calcium isotope .sup.41Ca to the patient, allowing a period of time to elapse sufficient for dissemination and reaction of the radioactive calcium isotope .sup.41Ca by the patient, obtaining a sample of the radioactive calcium isotope .sup.41Ca from the patient, isolating the calcium content of the sample in a form suitable for precise measurement of isotopic calcium concentrations, and measuring the calcium content to determine parameters of calcium metabolism in the patient.

  8. Calcium: a code coupling tool

    International Nuclear Information System (INIS)

    Today, the calculation performances of computers allow the precise and global simulation of complex industrial processes such as the functioning of a nuclear reactor core. One can question the need for the elaboration of new global numerical models in order to make use of the overall capability of computers. Another less time consuming solution consist in the coupling of existing well validated numerical models in order to make them working together. This paper presents the basic principles of the coupling of numerical codes, the tools required, the Calcium tool for codes coupling and an example of application of this tool in the coupling of the THYC (EdF), COCCINELLE (EdF) and CATHARE (CEA-EdF-Framatome) codes for the modeling of the thermal-hydraulic and neutronic behaviour of a reactor core during accidental situation. (J.S.)

  9. Combustion aspects of the consolidated mixtures of 5-amino-1H-tetrazole and potassium perchlorate; 5-amino-1H-tetorazoru to kaensosankariumu kongobutsu no nensho tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hasue, Kazuo.; Akanuma, Takanori.; Hodai, Harunori.; Date, Shingo. [National Defence Academy, Kanagawa (Japan). Dept. of Chemistry

    1999-02-28

    This paper describes the study concerning fundamental combustion features of the mixtures of 5-Amino-1H-tetrazole (HAT) and potassium perchlorate. Tetrazoles have been studied as a replacement for sodium azide and HAT, a typical tetrazole, is chosen in this study because it is readily available. The HAT/potassium perchlorate mixture was consolidated to form test strands. An optical strand burner was used to measure the burning rate of the strands. The maximum burning rate for HAT/KClO{sub 4} at 5MPa was about 32mm/s when the HAT concentration was 46wt% which is an excess amount of fuel. The extinction pressure increased as the concentration of HAT increased. The gaseous products of the combustions were analyzed by a gas chromatograph and the main products were CO{sub 2}, CO, and N{sub 2}. The heat of reaction of HAT/KClO{sub 4} reached a maximum when the HAT concentration was approximately 42wt%. (author)

  10. The influence of D2O, perchlorate, and variation in temperature on the potential-dependent contractile function of frog skeletal muscle

    International Nuclear Information System (INIS)

    D2O and perchlorate manifest opposing effects on the contractile function of skeletal muscle (amplitude of twitches and maximum K contractures, potential dependence of contraction and inactivation), and when combined the influence of one may effectively antagonize that of the other. The ratio of perchlorate concentrations required to produce effects of equal intensity, (e.g., twitch enhancement and restoration of maximum K contractures in media lacking divalent cations or containing a depressant concentration of a cationic amphipath) in H2O and D2O solutions was generally rather constant. These findings are compatible with the view that both agents can influence contractile function by virtue of their effects on solvent structure. In the absence of divalent cations, the effects of reduced temperature resemble those of D2O whereas the effects of increased temperature resemble those of the chaotropic anion. However, in other media, variation in temperature was found to result in additional nonsolvent effects so that low temperature could oppose rather than enhance the effects of D2O. These observations are discussed in terms of a model which postulates a role for solvent influences on the kinetics of two separate potential-dependent conformational transitions of membrane proteins which mediate the activation and inactivation of contraction in skeletal muscle

  11. Crystal structure of trans-bis(ethane-1,2-diamine-κ2N,N′bis(thiocyanato-κNchromium(III perchlorate from synchrotron data

    Directory of Open Access Journals (Sweden)

    Dohyun Moon

    2015-06-01

    Full Text Available The structure of the title compound, [Cr(NCS2(C2H8N22]ClO4, has been determined from synchroton data. The asymmetric unit consists of one half of a centrosymmetric CrIII complex cation and half of a perchlorate anion with the Cl atom on a twofold rotation axis. The CrIII ion is coordinated by the four N atoms of two ethane-1,2-diamine (en ligands in the equatorial plane and two N-bound thiocyanate (NCS− anions in a trans-axial arrangement, displaying a slightly distorted octahedral geometry with crystallographic inversion symmetry. The Cr—N(en bond lengths are in the range 2.053 (16–2.09 (2 Å, while the Cr—N(thiocyanate bond length is 1.983 (2 Å. The five-membered en rings are disordered over two sites, with occupancy ratios of 0.522 (16:0.478 (16. Each ClO4− anion is disordered over two sites with equal occupancy. The crystal structure is stabilized by intermolecular hydrogen bonds involving the en NH2 groups as donors and perchlorate O and thiocyanate S atoms as acceptors.

  12. Production of precipitated calcium carbonate from calcium silicates and carbon dioxide

    International Nuclear Information System (INIS)

    The possibilities for reducing carbon dioxide emissions from the pulp and paper industry by calcium carbonation are presented. The current precipitated calcium carbonate (PCC) production uses mined, crushed calcium carbonate as raw materials. If calcium silicates were used instead, carbon dioxide emissions from the calcination of carbonates would be eliminated. In Finland, there could, thus, be a potential for eliminating 200 kt of carbon dioxide emissions per year, considering only the PCC used in the pulp and paper industry. A preliminary investigation of the feasibility to produce PCC from calcium silicates and the potential to replace calcium carbonate as the raw material was made. Calcium carbonate can be manufactured from calcium silicates by various methods, but only a few have been experimentally verified. The possibility and feasibility of these methods as a replacement for the current PCC production process was studied by thermodynamic equilibrium calculations using HSC software and process modelling using Aspen Plus[reg]. The results from the process modelling showed that a process that uses acetic acid for extraction of the calcium ions is a high potential option for sequestering carbon dioxide by mineral carbonation. The main obstacle seems to be the limited availability and relatively high price of wollastonite, which is a mineral with high calcium silicate content. An alternative is to use the more common, but also more complex, basalt rock instead

  13. Effect of calcium intake on urinary oxalate excretion in calcium stone-forming patients

    Directory of Open Access Journals (Sweden)

    Nishiura J.L.

    2002-01-01

    Full Text Available Dietary calcium lowers the risk of nephrolithiasis due to a decreased absorption of dietary oxalate that is bound by intestinal calcium. The aim of the present study was to evaluate oxaluria in normocalciuric and hypercalciuric lithiasic patients under different calcium intake. Fifty patients (26 females and 24 males, 41 ± 10 years old, whose 4-day dietary records revealed a regular low calcium intake (<=500 mg/day, received an oral calcium load (1 g/day for 7 days. A 24-h urine was obtained before and after load and according to the calciuria under both diets, patients were considered as normocalciuric (NC, N = 15, diet-dependent hypercalciuric (DDHC, N = 9 or diet-independent hypercalciuric (DIHC, N = 26. On regular diet, mean oxaluria was 30 ± 14 mg/24 h for all patients. The 7-day calcium load induced a significant decrease in mean oxaluria compared to the regular diet in NC and DIHC (20 ± 12 vs 26 ± 7 and 27 ± 18 vs 32 ± 15 mg/24 h, respectively, P<0.05 but not in DDHC patients (22 ± 10 vs 23 ± 5 mg/24 h. The lack of an oxalate decrease among DDHC patients after the calcium load might have been due to higher calcium absorption under higher calcium supply, with a consequent lower amount of calcium left in the intestine to bind with oxalate. These data suggest that a long-lasting regular calcium consumption <500 mg was not associated with high oxaluria and that a subpopulation of hypercalciuric patients who presented a higher intestinal calcium absorption (DDHC tended to hyperabsorb oxalate as well, so that oxaluria did not change under different calcium intake.

  14. Transgenic plants with increased calcium stores

    Science.gov (United States)

    Wyatt, Sarah (Inventor); Tsou, Pei-Lan (Inventor); Robertson, Dominique (Inventor); Boss, Wendy (Inventor)

    2004-01-01

    The present invention provides transgenic plants over-expressing a transgene encoding a calcium-binding protein or peptide (CaBP). Preferably, the CaBP is a calcium storage protein and over-expression thereof does not have undue adverse effects on calcium homeostasis or biochemical pathways that are regulated by calcium. In preferred embodiments, the CaBP is calreticulin (CRT) or calsequestrin. In more preferred embodiments, the CaBP is the C-domain of CRT, a fragment of the C-domain, or multimers of the foregoing. In other preferred embodiments, the CaBP is localized to the endoplasmic reticulum by operatively associating the transgene encoding the CaBP with an endoplasmic reticulum localization peptide. Alternatively, the CaBP is targeted to any other sub-cellular compartment that permits the calcium to be stored in a form that is biologically available to the plant. Also provided are methods of producing plants with desirable phenotypic traits by transformation of the plant with a transgene encoding a CaBP. Such phenotypic traits include increased calcium storage, enhanced resistance to calcium-limiting conditions, enhanced growth and viability, increased disease and stress resistance, enhanced flower and fruit production, reduced senescence, and a decreased need for fertilizer production. Further provided are plants with enhanced nutritional value as human food or animal feed.

  15. Treatment of Perchlorate-Contaminated Groundwater Using Highly-Selective, Regenerable Anion-Exchange Resins at Edwards Air Force Base

    Energy Technology Data Exchange (ETDEWEB)

    Gu, B.

    2003-05-30

    Selective ion exchange is one of the most effective treatment technologies for removing low levels of perchlorate (ClO{sub 4}{sup -}) from contaminated water because of its high efficiency without adverse impacts on the water quality caused by adding or removing any chemicals or nutrients. This report summarizes both the laboratory and a field pilot-scale studies to determine the ability and efficiency of the bifunctional synthetic resins to remove ClO{sub 4}{sup -} from the contaminated groundwater at the Edwards Air Force Base in California. Regeneration of the resins after groundwater treatment was also evaluated using the FeCl{sub 3}-HCl regeneration technique recently developed at Oak Ridge National Laboratory. On the basis of this study, the bifunctional resin, D-3696 was found to be highly selective toward ClO{sub 4}{sup -} and performed much better than one of the best commercial nitrate-selective resins (Purolite A-520E) and more than an order of magnitude better than the Purolite A-500 resin (with a relatively low selectivity). At an influent concentration of {approx} 450 {micro}g/L ClO{sub 4}{sup -} in groundwater, the bifunctional resin bed treated {approx} 40,000 empty bed volumes of groundwater before a significant breakthrough of ClO{sub 4}{sup -} occurred. The presence of relatively high concentrations of chloride and sulfate in site groundwater did not appear to affect the ability of the bifunctional resin to remove ClO{sub 4}{sup -}. However, the presence of high iron or iron oxyhydroxides and/or biomass in groundwater caused a significant fouling of the resin beds and greatly influenced the effectiveness in regenerating the resins sorbed with ClO{sub 4}{sup -}. Under such circumstances, a prefilter ({approx} 0.5-1 {micro}m) was found to be necessary to remove these particulates and to reduce the risk of fouling of the resin beds. Without significant fouling, the resin bed could be effectively regenerated by the FeCl{sub 3} displacement technique

  16. The effects of surface oxidation and fluorination of boron-doped diamond anodes on perchlorate formation and organic compound oxidation

    International Nuclear Information System (INIS)

    This research investigated the effects of surface functional groups on both rates of organic compound oxidation (phenol, p-nitrophenol, benzoquinone, and oxalic acid) and perchlorate (ClO4−) formation at boron-doped diamond (BDD) film anodes at 20 °C. X-ray photoelectron spectroscopy measurements determined that various oxygenated functional groups (e.g., C-OH, C=O, COOH) were incorporated on the BDD surface by applying an anodic ageing process, and fluorine functional groups (e.g., C-F, -CnF2n+1) were incorporated by electrochemical oxidation of aqueous perfluorooctanoic acid solutions. Batch oxidation experiments revealed that ClO4− formation via the oxidation of ClO3− was highly variable during anodic ageing, which was attributed to changes in oxygenated functional groups, while organic compound oxidation rates were not significantly affected. The fluorinated electrode showed a lower ClO4− formation rate (19 ± 4 μmoles m−2 min−1) compared to the oxygenated electrode (436 ± 26 μmoles m−2 min−1) indicating the fluorinated surface limits ClO4− production. Measurement of the electrode response to the Fe(CN)63−/4− redox couple using cyclic voltammetry and electrochemical impedance spectroscopy indicated that lower ClO4− formation on the fluorinated electrode was likely a result of dipole-dipole interactions between the negatively charged F atoms and ClO3− and steric hindrance caused by the perfluorocarbon chains. This effect along with the hydrophobicity of the fluorinated electrode resulted in significantly lower ClO4− formation (96% decrease) while slightly enhancing measured oxidation rates of hydrophobic organic compounds. The use of benzoquinone as OH· probe confirmed that the fluorination process did not inhibit OH· production. The rate of benzoquinone oxidation was 2212 ± 183 μmoles m−2 min−1 on the oxygenated electrode and 2926 ± 201 μmoles m−2 min−1 on the fluorinated electrode. Density functional theory

  17. Calcium: A Nutrient Deserving a Special Issue

    Directory of Open Access Journals (Sweden)

    Susan J. Whiting

    2010-10-01

    Full Text Available Interest in calcium has continued since the 1980s when its role in promoting bone growth and retention was established in clinical trials of children and postmenopausal women. The human nutrition functions now attributed to calcium have expanded beyond bone health to include other conditions such as body weight maintenance. While most efforts have been focused on the findings that dietary intakes are low, there are emerging data on safety concerns of excess amounts. This Special Issue on calcium nutrition, spanning the lifecycle from critically ill neonates through to older adults, has been written by some of the leading researchers in this field.

  18. Sorption of UO22+ on calcium carbonate

    International Nuclear Information System (INIS)

    Sorption of uranyl ions on calcium carbonate from aqueous solutions featuring different concentration of calcium nitrate was studied experimentally. It is shown that uranium sorption decreases with calcium concentration growth in solution, irrespective of the ratio of solid phase and solution masses. Specific sorption of uranium per unit of the sorbent surface depends linearly on the ratio of UO22+ and Ca2+ ions activities in solution with proportionality factor (sorption equilibrium constant) 1.71 ± 0.16 mol/m2 at 20 deg C

  19. Calcium signaling in physiology and pathophysiology

    Institute of Scientific and Technical Information of China (English)

    He-ping CHENG; Sheng WEI; Li-ping WEI; Alexei VERKHRATSKY

    2006-01-01

    Calcium ions are the most ubiquitous and pluripotent cellular signaling molecules that control a wide variety of cellular processes.The calcium signaling system is represented by a relatively limited number of highly conserved transporters and channels,which execute Ca2+ movements across biological membranes and by many thousands of Ca2+-sensitive effectors.Molecular cascades,responsible for the generation of calcium signals,are tightly controlled by Ca2+ ions themselves and by genetic factors,which tune the expression of different Ca2+-handling molecules according to adaptational requirements.Ca2+ ions determine normal physiological reactions and the development of many pathological processes.

  20. Modulation of Intracellular Calcium Levels by Calcium Lactate Affects Colon Cancer Cell Motility through Calcium-Dependent Calpain

    OpenAIRE

    Pasupathi Sundaramoorthy; Jae Jun Sim; Yeong-Su Jang; Siddhartha Kumar Mishra; Keun-Yeong Jeong; Poonam Mander; Oh Byung Chul; Won-Sik Shim; Seung Hyun Oh; Ky-Youb Nam; Hwan Mook Kim

    2015-01-01

    Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK) plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca2+) supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca2+ bound lactate (CaLa), its downstrea...