Erythrocyte membrane alterations as the basis of chlorate toxicity.

PubMed

Singelmann, E; Wetzel, E; Adler, G; Steffen, C

1984-03-01

The effects of sodium chlorate and of sodium nitrite on human erythrocytes were studied in vitro. Nitrite rapidly oxidised haemoglobin and glutathione; reduction of methaemoglobin (Hbi) by methylene blue was complete during 3 h of incubation with nitrite. With chlorate, a concentration-dependent lag phase was seen before Hbi was formed. After prolonged incubation, Hbi could no longer be reduced with methylene blue. Several other effects were observed that explain the clinical picture of chlorate poisoning which involves haemolysis followed by disseminated intravascular coagulation and renal failure: increased permeability to cations, increased resistance to hypotonic haemolysis and prolonged filtration time through polycarbonate membranes with cylindrical pores of 5 micron diameter. This suggests an increased membrane rigidity due to membrane protein polymerisation, as demonstrated by SDS polyacrylamide gel electrophoresis. Simultaneously, erythrocyte enzymes were inactivated, primarily glucose-6-phosphate dehydrogenase which is necessary for the therapeutic effect of methylene blue. This explains the inefficacy of methylene blue in the treatment of a case of chlorate poisoning that we observed (Arch. Toxicol., 48 (1981) 281).

AN ADDITIVE EFFECT OF A MIXTURE OF AMMONIUM PERCHLORATE AND SODIUM CHLORATE ON PITUTARY-THYROID AXIS IN MALE F-344 RATS

EPA Science Inventory

An Additive Effect of a Mixture of Ammonium Perchlorate
and Sodium Chlorate on Pitutary-Thyroid Axis in Male F-344 Rats

Moazzam A. Khan 1,2,, 3Suzanne E. Fenton. 2Adam E. Swank, ZGeremy W. Knapp, 2Susan D.
Hester, and 2Douglas C. Wolf. 1NRC, 2Environmental Carcinog...

Effect of intravenous or oral sodium chlorate administration on the fecal shedding of Escherichia coli in sheep

USDA-ARS?s Scientific Manuscript database

The effect of gavage or intravenous (i.v.) administration of sodium chlorate salts on the fecal shedding of generic Escherichia coli in wether lambs was studied. To this end, 9 lambs (27 +/- 2.5 kg) were administered 150 mg NaClO3 per kg BW by gavage or i.v. infusion in a cross-over design with sal...

Environmentally Sustainable Yellow Smoke Formulations for Use in the M194 Hand Held Signal

DTIC Science & Technology

2012-06-10

of the pyrotechnic train through the system hardware, potassium chlorate (oxidizer) and the sugar (fuel, or reducing agent) engage in a reduction...1: Composition of M194 control formulation Ingredient Wt. % Function Potassium Chlorate 35.0 Oxidizer Sugar (sucrose) 20.0 Fuel Vat yellow...Experimental Section 1. Materials Potassium chlorate , potassium nitrate, sodium bicarbonate, stearic acid, and sugar were purchased from Hummel

Chlorate poisoning in beef cattle

PubMed Central

Blakley, Barry R.; Fraser, Lorrie M.; Waldner, Cheryl

2007-01-01

A disease syndrome characterized by hemolysis, methemoglobinemia, methemoglobinuria, and death was observed in a herd of purebred Limousin beef cattle grazing on pasture in November in Alberta. Improper disposal of the nonselective herbicide, sodium chlorate, was identified as the causal agent. Highly variable blood methemoglobin levels reflected differences in herbicide consumption. PMID:17987970

Catalyzed sodium chlorate candles

NASA Technical Reports Server (NTRS)

Malich, C. W.; Wydeven, T.

1972-01-01

The catalytic effect of cobalt powder on chlorate decomposition has been confirmed. Catalysis is enhanced by oxidation of the metal during burning. Catalysts other than cobalt compounds should also be effective; the complete elimination of fuel has shown that the oxidation of cobalt during decomposition is not a vital factor in the improved performance of catalyzed candles.

Chloroxyanion Residue on Seeds and Sprouts after Chlorine Dioxide Sanitation of Alfalfa Seed.

PubMed

Smith, David J; Herges, Grant R

2018-02-28

The effects of a 6-h chlorine dioxide sanitation of alfalfa seed (0, 50, 100, and 200 mg/kg seed) on total coliform bacteria, seed germination, and the presence of chlorate and perchlorate residues in seed rinse, seed soak, and alfalfa sprouts was determined. Chlorate residues in 20,000 mg/L calcium hypochlorite, commonly used to disinfect seed, were quantified. Chlorine dioxide treatment reduced (P < 0.05) total coliforms on seeds with no effect (P > 0.05) on germination. Dose-dependent sodium chlorate residues were present in seed rinse (4.1 to 31.2 μg/g seed) and soak (0.7 to 8.3 μg/g seed) waters, whereas chlorate residues were absent (LOQ 5 ng/g) in sprouts, except for 2 of 5 replicates from the high chlorine dioxide treatment. Copious chlorate residues were present (168 to 1260 mg/L) in freshly prepared 20,000 mg/L calcium hypochlorite solution, and storage at room temperature increased chlorate residues significantly (P < 0.01).

Defeating Improvised Explosive Devices (IED): Asymmetric Threats and Capability Gaps

DTIC Science & Technology

2011-03-23

City, Oklahoma bombings in 1995. In order to adapt and avoid detection, terrorists are exploring other options, such as using potassium chlorate ...white, odorless powder) or sodium chlorate (yellow, odorless powder) when making IEDs. High-profile, historic examples include the London attacks...and potassium nitrate. It is the main ingredient found in fireworks. In the past it was used as a propellant powder in ammunition, http

Influence of drinking water treatments on chlorine dioxide consumption and chlorite/chlorate formation.

PubMed

Sorlini, Sabrina; Gialdini, Francesca; Biasibetti, Michela; Collivignarelli, Carlo

2014-05-01

Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%. Copyright © 2014 Elsevier Ltd. All rights reserved.

Infrared Multiple Photon Dissociation Spectroscopy of Sodium and Potassium Chlorate Anions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan P. Dain; Christopher M. Leavitt; Jos Oomens

2010-01-01

The structures of gas-phase, metal chlorate anions with the formula [M(ClO3)2]-, M=Na and K, were determined using tandem mass spectrometry and infrared multiple photon dissociation (IRMPD) spectroscopy. Structural assignments for both anions are based on comparisons of the experimental vibrational spectra for the two species to those predicted by density functional theory and involve conformations that feature either bidentate or tridentate coordination of the cation by chlorate. Our results strongly suggest that a structure in which both chlorate anions are bidentate ligands is preferred for [Na(ClO3)2]-. However, for [K(ClO3)2]- the best agreement between experimental and theoretical spectra is obtained frommore » a composite of predicted spectra for which the chlorate anions are either both bidentate or both tridentate ligands. In general, we find that the overall accuracy of DFT calculations for prediction of IR spectra is dependent on both functional and basis set, with best agreement achieved using frequencies generated at the B3LYP/6-311+g(3df) level of theory.« less

Infrared multiple photon dissociation spectroscopy of sodium and potassium chlorate anions.

PubMed

Dain, Ryan P; Leavitt, Christopher M; Oomens, Jos; Steill, Jeffrey D; Groenewold, Gary S; Van Stipdonk, Michael J

2010-01-01

The structures of gas-phase, metal chlorate anions with the formula [M(ClO(3))(2)](-), M = Na and K, were determined using tandem mass spectrometry and infrared multiple photon dissociation (IRMPD) spectroscopy. Structural assignments for both anions are based on comparisons of the experimental vibrational spectra for the two species with those predicted by density functional theory (DFT) and involve conformations that feature either bidentate or tridentate coordination of the cation by chlorate. Our results strongly suggest that a structure in which both chlorate anions are bidentate ligands is preferred for [Na(ClO(3))(2)](-). However, for [K(ClO(3))(2)](-) the best agreement between experimental and theoretical spectra is obtained from a composite of predicted spectra for which the chlorate anions are either both bidentate or both tridentate ligands. In general, we find that the overall accuracy of DFT calculations for prediction of IR spectra is dependent on both functional and basis set, with best agreement achieved using frequencies generated at the B3LYP/6-311+g(3df) level of theory. Copyright 2009 John Wiley & Sons, Ltd.

21 CFR 173.300 - Chlorine dioxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... hypochlorite and hydrochloric acid. (ii) Treating an aqueous solution of sodium chlorate with hydrogen peroxide... electrolysis. (2) The generator effluent contains at least 90 percent (by weight) of chlorine dioxide with...

Synthesis and Characterization of Highly Intercalated Graphite Bisulfate

NASA Astrophysics Data System (ADS)

Salvatore, Marcella; Carotenuto, Gianfranco; De Nicola, Sergio; Camerlingo, Carlo; Ambrogi, Veronica; Carfagna, Cosimo

2017-03-01

Different chemical formulations for the synthesis of highly intercalated graphite bisulfate have been tested. In particular, nitric acid, potassium nitrate, potassium dichromate, potassium permanganate, sodium periodate, sodium chlorate, and hydrogen peroxide have been used in this synthesis scheme as the auxiliary reagent (oxidizing agent). In order to evaluate the presence of delamination, and pre-expansion phenomena, and the achieved intercalation degree in the prepared samples, the obtained graphite intercalation compounds have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR), micro-Raman spectroscopy ( μ-RS), and thermal analysis (TGA). Delamination and pre-expansion phenomena were observed only for nitric acid, sodium chlorate, and hydrogen peroxide, while the presence of strong oxidizers (KMnO4, K2Cr2O7) led to stable graphite intercalation compounds. The largest content of intercalated bisulfate is achieved in the intercalated compounds obtained from NaIO4 and NaClO3.

Synthesis and Characterization of Highly Intercalated Graphite Bisulfate.

PubMed

Salvatore, Marcella; Carotenuto, Gianfranco; De Nicola, Sergio; Camerlingo, Carlo; Ambrogi, Veronica; Carfagna, Cosimo

2017-12-01

Different chemical formulations for the synthesis of highly intercalated graphite bisulfate have been tested. In particular, nitric acid, potassium nitrate, potassium dichromate, potassium permanganate, sodium periodate, sodium chlorate, and hydrogen peroxide have been used in this synthesis scheme as the auxiliary reagent (oxidizing agent). In order to evaluate the presence of delamination, and pre-expansion phenomena, and the achieved intercalation degree in the prepared samples, the obtained graphite intercalation compounds have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR), micro-Raman spectroscopy (μ-RS), and thermal analysis (TGA). Delamination and pre-expansion phenomena were observed only for nitric acid, sodium chlorate, and hydrogen peroxide, while the presence of strong oxidizers (KMnO 4 , K 2 Cr 2 O 7 ) led to stable graphite intercalation compounds. The largest content of intercalated bisulfate is achieved in the intercalated compounds obtained from NaIO 4 and NaClO 3 .

Assessment of residual active chlorine in sodium hypochlorite solutions after dissolution of porcine incisor pulpal tissue.

PubMed

Clarkson, R M; Smith, T K; Kidd, B A; Evans, G E; Moule, A J

2013-12-01

In previous studies, surfactant-containing Hypochlor brands of sodium hypochlorite showed better tissue solubilizing abilities than Milton; differences not explained by original active chlorine content or presence of surfactant. It was postulated that exhaustion of active chlorine content could explain differences. This study aimed to assess whether Milton's poorer performance was due to exhaustion of active chlorine. Parallel experiments assessed the influence of titration methods, and the presence of chlorates, on active chlorine measurements. Time required to dissolve one or groups of 10 samples of porcine incisor pulp samples in Milton was determined. Residual active chlorine was assessed by thermometric titration. Iodometric and thermometric titration was carried out on samples of Milton. Chlorate content was also measured. Dissolution of single and 10 pulp samples caused a mean loss of 1% and 3% respectively of active chlorine, not being proportional to tissue dissolved. Thermometric ammonium ion titration resulted in 10% lower values than iodometric titration. Chlorate accounted for much of this difference. Depletion of active chlorine is not the reason for differences in tissue dissolving capabilities of Milton. Thermometric ammonium ion titration gives more accurate measurement of active chlorine content than iodometric titration. © 2013 Australian Dental Association.

21 CFR 173.300 - Chlorine dioxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... chlorate with hydrogen peroxide in the presence of sulfuric acid. (iii) Treating an aqueous solution of sodium chlorite by electrolysis. (2) The generator effluent contains at least 90 percent (by weight) of...

21 CFR 173.300 - Chlorine dioxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... chlorate with hydrogen peroxide in the presence of sulfuric acid. (iii) Treating an aqueous solution of sodium chlorite by electrolysis. (2) The generator effluent contains at least 90 percent (by weight) of...

40 CFR 415.661 - Specialized definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... shall apply to this subpart. (b) The term product shall mean sodium chlorate. (c) The term chromium shall mean the total chromium present in the process wastewater stream exiting the wastewater treatment...

40 CFR 415.661 - Specialized definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... shall apply to this subpart. (b) The term product shall mean sodium chlorate. (c) The term chromium shall mean the total chromium present in the process wastewater stream exiting the wastewater treatment...

40 CFR 415.661 - Specialized definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... shall apply to this subpart. (b) The term product shall mean sodium chlorate. (c) The term chromium shall mean the total chromium present in the process wastewater stream exiting the wastewater treatment...

40 CFR 415.661 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... shall apply to this subpart. (b) The term product shall mean sodium chlorate. (c) The term chromium shall mean the total chromium present in the process wastewater stream exiting the wastewater treatment...

40 CFR 415.661 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... shall apply to this subpart. (b) The term product shall mean sodium chlorate. (c) The term chromium shall mean the total chromium present in the process wastewater stream exiting the wastewater treatment...

The response of aircraft oxygen generators exposed to elevated temperatures

DOT National Transportation Integrated Search

2003-04-01

The purpose of this testing was to determine the temperatures that would cause self-activation of sodium chlorate oxygen generators. The data will be used to establish the degree of thermal protection that would be required to prevent the activation ...

Kinetic resolution of racemic mixtures in gel media

NASA Astrophysics Data System (ADS)

Petrova, Rositza Iordanova

The goal of this research was to investigate the effect of chiral gels on the chiral crystal nucleation and growth and assess the gels' potential as media for kinetic separation of racemic mixtures. The morphologies of asparagine monohydrate and sodium bromate crystals grown in different gel media were examined in order to discern the effect of gel structure and density on the relative growth rates of those materials. Different crystal habits were observed when the gel chemical composition, density and solute concentration were varied. These studies showed that the physical properties of the gel, such as gel density and pore size, as well as its chemical composition affect the crystal habit. The method of kinetic resolution in gel media was first applied to sodium chlorate, which is achiral in solution but crystallizes in a chiral space group. Crystallization in agarose gels yielded an enantiomorphic bias, the direction and magnitude of which could be affected by changing the temperature or by the addition of an achiral cosolvent. Aqueous gels at 6°C produced crystalline mixtures enriched with the d-enantiomorph, while crystallization under MeOH diffusion favored l-crystals. Optimized conditions yielded e.e. of 53% of l-enantiomorph. The method was next applied to the organic molecular crystals of asparagine monohydrate and threonine. Asparagine monohydrate growth in aqueous agarose and iota-carrageenan gels produced crystal mixtures enriched with D-enantiomer. The degree of resolution was higher when the total amount of asparagine crystallized was low. The success of the resolution depends strongly on the concentrations of solute and the geling substance. Growth from agarose gels yielded e.e. of 44% under optimized conditions. The same method was applied to the resolution of Thr, albeit with modest success. In an effort to improve the resolution of asparagine monohydrate, agarose was synthetically modified by esterifying its side chains with homochiral asparagyl groups and used as a kinetic resolution media. The crystallization from L-Asn-agarose favored crystallization of L-enantiomer (28% e.e.), while D-Asn-agarose favored D-enantiomer (40% e.e.). The degree of resolution was sensitive to the concentrations of the gel and the total amount of crystallized asparagine, but the media was no better than that in pure agarose.

40 CFR 180.1020 - Sodium chlorate; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., forage Sorghum, grain, grain Sorghum, grain, stover Soybean, forage Soybean, hay Soybean, seed Sunflower... in accordance with good agricultural practice on the following crops: Bean, dry, seed Corn, field..., sweet, stover Cotton, undelinted seed Flax, seed Grain, aspirated fractions Guar, seed Pea, southern...

40 CFR 180.1020 - Sodium chlorate; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., forage Sorghum, grain, grain Sorghum, grain, stover Soybean, forage Soybean, hay Soybean, seed Sunflower... in accordance with good agricultural practice on the following crops: Bean, dry, seed Corn, field..., sweet, stover Cotton, undelinted seed Flax, seed Grain, aspirated fractions Guar, seed Pea, southern...

40 CFR 415.666 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Pretreatment standards for new sources...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Sodium Chlorate Production Subcategory § 415.666 Pretreatment standards for new sources (PSNS). Except as provided in 40 CFR...

Vibrational and Thermal Properties of Oxyanionic Crystals

NASA Astrophysics Data System (ADS)

Korabel'nikov, D. V.

2018-03-01

The vibrational and thermal properties of dolomite and alkali chlorates and perchlorates were studied in the gradient approximation of density functional theory using the method of a linear combination of atomic orbitals (LCAO). Long-wave vibration frequencies, IR and Raman spectra, and mode Gruneisen parameters were calculated. Equation-of-state parameters, thermodynamic potentials, entropy, heat capacity, and thermal expansion coefficient were also determined. The thermal expansion coefficient of dolomite was established to be much lower than for chlorates and perchlorates. The temperature dependence of the heat capacity at T > 200 K was shown to be generally governed by intramolecular vibrations.

Interpreting the near infrared region of explosives.

PubMed

Zapata, Félix; Ferreiro-González, Marta; García-Ruiz, Carmen

2018-06-07

The NIR spectra from 1000 to 2500 nm of 18 different explosives, propellant powders and energetic salts were collected and interpreted. NIR spectroscopy is known to provide information about the combination bands and overtones of highly anharmonic vibrations as those occurring in XH bonds (CH, NH and OH). Particularly intense and complex were the bands corresponding to the first combination region (2500-1900 nm) and first overtone stretching mode (2ν) of CH and NH bonds (1750-1450 nm). Inorganic oxidizing salts including sodium/potassium nitrate, sodium/potassium chlorate, and sodium/potassium perchlorate displayed low intense or no NIR bands. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization and Fate of Gun and Rocket Propellant Residues on Testing and Training Ranges: Interim Report 1

DTIC Science & Technology

2007-01-01

sulfide, and calcium silicide . Oxidizing agents include potassium chlorate and barium nitrate. 1-4 ERDC TR-07-1 a. Propellant grain shapes. b...evaporated to dryness under a gentle stream of forced air. The dried extracts were combined with 5 mL 5N sodium hydroxide, and the vials were placed in a...phase was 0.5M carbonate:0.5M bicarbonate and the flow rate was 1.8 mL/min. Injection volume was 50 µL. Potassium nitrate and sodium nitrite were

Optimal Design of Piezoelectric Materials for Maximal Energy Harvesting

DTIC Science & Technology

2015-06-01

Wright. . 22 Figure 3.1 Energy harvesting bimorph cantilever with distributed piezoelectric transducers (gray) bonded to a substrate ( white ). Adapted...certain materials, such as zinc blende, sodium chlorate, boracite, tourmaline, cane sugar, Rochelle salt, and quartz, mechanical stresses induce...cantilever with distributed piezoelectric transducers (gray) bonded to a substrate ( white ). Adapted from Dutoit, Wardle and Kim [16]. 25 The general equations

Reduction of Campylobacter jejuni on chicken wings by chemical treatments.

PubMed

Zhao, Tong; Doyle, Michael P

2006-04-01

Eight chemicals, including glycerol monolaurate, hydrogen peroxide, acetic acid, lactic acid, sodium benzoate, sodium chlorate, sodium carbonate, and sodium hydroxide, were tested individually or in combination for their ability to inactivate Campylobacter jejuni at 4 degrees C in suspension. Results showed that treatment for up to 20 min with 0.01% glycerol monolaurate, 0.1% sodium benzoate, 50 or 100 mM sodium chlorate, or 1% lactic acid did not substantially (< or = 0.5 log CFU/ml) reduce C. jejuni populations but that 0.1 and 0.2% hydrogen peroxide for 20 min reduced C. jejuni populations by ca. 2.0 and 4.5 log CFU/ml, respectively. By contrast, treatments with 0.5, 1.0, 1.5, and 2.0% acetic acid, 25, 50, and 100 mM sodium carbonate, and 0.05 and 0.1 N sodium hydroxide reduced C. jejuni populations by >5 log CFU/ml within 2 min. A combination of 0.5% acetic acid plus 0.05% potassium sorbate or 0.5% acetic acid plus 0.05% sodium benzoate reduced C. jejuni populations by >5 log CFU/ml within 1 min; however, substituting 0.5% lactic acid for 0.5% acetic acid was not effective, with a reduction of C. jejuni of <0.5 log CFU/ml. A combination of acidic calcium sulfate, lactic acid, ethanol, sodium dodecyl sulfate, and polypropylene glycol (ACS-LA) also reduced C. jejuni in suspension by >5 log CFU/ml within 1 min. All chemicals or chemical combinations for which there was a >5-log/ml reduction of C. jejuni in suspension were further evaluated for C. jejuni inactivation on chicken wings. Treatments at 4 degrees C of 2% acetic acid, 100 mM sodium carbonate, or 0.1 N sodium hydroxide for up to 45 s reduced C. jejuni populations by ca. 1.4, 1.6, or 3.5 log CFU/g, respectively. Treatment with ACS-LA at 4 degrees C for 15 s reduced C. jejuni by >5 log CFU/g to an undetectable level. The ACS-LA treatment was highly effective in chilled water at killing C. jejuni on chicken and, if recycled, may be a useful treatment in chill water tanks for poultry processors to reduce campylobacters on poultry skin after slaughter.

Safety and efficacy of low-dose, subacute exposure of mature ewes to sodium chlorate

USDA-ARS?s Scientific Manuscript database

The objective was to determine the safety and efficacy of low-dose, subacute exposure of mature ewes to NaClO3 in the drinking water. Twenty-five ewes (BW = 62.5 ± 7.3 kg) were placed indoors in individual pens with ad libitum access to water and feed. After 7 d of adaptation, ewes were assigned ran...

The indirect detection of bleach (sodium hypochlorite) in beverages as evidence of product tampering.

PubMed

Jackson, David S; Crockett, David F; Wolnik, Karen A

2006-07-01

Bleach (sodium hypochlorite) has been identified as the adulterant in a relatively large number of product tamperings that have been investigated by the Forensic Chemistry Center (FCC) of the U.S. Food and Drug Administration. In this work, household bleach was added to 23 different beverages at each of three levels. The impact of sodium hypochlorite on these beverages over a 13-day study period was evaluated using the following techniques: diphenylamine spot test for oxidizing agents, potassium iodide-starch test paper for oxidizing agents, pH, iodometric titration for quantitating hypochlorite, ion chromatography for chloride and chlorate quantitation, automated headspace sampling with gas chromatography-flame ionization detection (GC-FID) for determination of chloroform, and visual and organoleptic observations. This study has shown that hypochlorite is fragile when added to most common beverages and typically breaks down either partially or completely over time. In cases where a beverage is suspected of being adulterated with bleach but tests for hypochlorite are negative, it is still possible to characterize the product to demonstrate that the results are consistent with the addition of bleach. An adulterated product will give a positive test for oxidizing agents using the diphenylamine spot test. It is likely that the pH of the adulterated product will be higher than a control of that product. Ion chromatographic analysis shows elevated chloride and chlorate as compared with a control. And, chloroform may also be detected by GC-FID especially if the beverage that was adulterated contains citric acid.

Oxychlorine and Chloride/Ferrian Saponite Mixtures as a Possible Source of Hydrochloric Acid Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Hogancamp, J. V.; Sutter, B.; Archer, D., Jr.; Ming, D. W.; Mahaffy, P. R.

2017-12-01

The Sample Analysis at Mars (SAM) instrument on board the Curiosity Rover has detected HCl gas releases from several analyzed Gale Crater sediments, which are attributed to the presence of perchlorates, chlorates, and/or chlorides in martian sediment. Previous SAM analog laboratory analyses found that most pure perchlorates and chlorates produced 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 characteristic O2 releases at similar temperatures as Gale Crater materials, but most of these mixtures did not produce HCl releases comparable to those detected by the SAM instrument. Perchlorates, chlorates, and chlorides were mixed with Gale Crater analog ferrian saponite to understand evolved HCl detected by SAM. Evolved water from thermally decomposing saponite is hypothesized to react with residual chloride phases from oxychlorine decomposition to produce high temperature (>700°C) HCl. Mixtures of chlorates, perchlorates, or chlorides with ferrian saponite were heated to 1000 °C in a laboratory analog SAM instrument. Results demonstrated that all chlorate and perchlorate mixtures produce HCl releases below 1000 °C when mixed with ferrian saponite. Mixtures of chlorides with ferrian saponite produced no oxygen releases but did produce HCl releases with peaks below 1000 °C. Ferrian saponite/Mg-chlorate mixtures produced two HCl releases (347 and 820 °C) similar to the Cumberland drilled sample. Additionally, sodium chloride mixed with ferrian saponite produced no oxygen releases and an HCl release (767 °C) similar to the Quela drilled sample. The Marimba drilled sample, which also produced no oxychlorine-derived oxygen, produced a high temperature HCl release that may be the result of chloride(s) reacting with evolved water from thermally decomposing ferrian saponite. Results of this work demonstrated that chlorides in the presence of evolved water from thermally decomposing saponite can explain the high temperature evolved HCl detected by SAM. Chlorides may either be native to the sample or be produced by perchlorate/chlorate thermal decomposition in order to yield Cl for high temperature (>700 °C) HCl production. Mg bearing Cl phases tend to produce two HCl releases (347-496 and 820 °C) while Ca and Na bearing phases produced one high temperature (>700 °C) HCl release. HCl release temperatures can be used to indicate the cation-type of the oxychlorine phase or chloride which is critical to understanding past geochemical conditions in Gale Crater.

A stable room-temperature sodium-sulfur battery.

PubMed

Wei, Shuya; Xu, Shaomao; Agrawral, Akanksha; Choudhury, Snehashis; Lu, Yingying; Tu, Zhengyuan; Ma, Lin; Archer, Lynden A

2016-06-09

High-energy rechargeable batteries based on earth-abundant materials are important for mobile and stationary storage technologies. Rechargeable sodium-sulfur batteries able to operate stably at room temperature are among the most sought-after platforms because such cells take advantage of a two-electron-redox process to achieve high storage capacity from inexpensive electrode materials. Here we report a room-temperature sodium-sulfur battery that uses a microporous carbon-sulfur composite cathode, and a liquid carbonate electrolyte containing the ionic liquid 1-methyl-3-propylimidazolium-chlorate tethered to SiO2 nanoparticles. We show that these cells can cycle stably at a rate of 0.5 C (1 C=1675, mAh g(-1)) with 600 mAh g(-1) reversible capacity and nearly 100% Coulombic efficiency. By means of spectroscopic and electrochemical analysis, we find that the particles form a sodium-ion conductive film on the anode, which stabilizes deposition of sodium. We also find that sulfur remains interred in the carbon pores and undergo solid-state electrochemical reactions with sodium ions.

Phenotypic and genotypic description of Sedimenticola selenatireducens strain CUZ, a marine (per)chlorate-respiring gammaproteobacterium, and its close relative the chlorate-respiring Sedimenticola strain NSS.

PubMed

Carlström, Charlotte I; Loutey, Dana E; Wang, Ouwei; Engelbrektson, Anna; Clark, Iain; Lucas, Lauren N; Somasekhar, Pranav Y; Coates, John D

2015-04-01

Two (per)chlorate-reducing bacteria, strains CUZ and NSS, were isolated from marine sediments in Berkeley and San Diego, CA, respectively. Strain CUZ respired both perchlorate and chlorate [collectively designated (per)chlorate], while strain NSS respired only chlorate. Phylogenetic analysis classified both strains as close relatives of the gammaproteobacterium Sedimenticola selenatireducens. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) preparations showed the presence of rod-shaped, motile cells containing one polar flagellum. Optimum growth for strain CUZ was observed at 25 to 30 °C, pH 7, and 4% NaCl, while strain NSS grew optimally at 37 to 42 °C, pH 7.5 to 8, and 1.5 to 2.5% NaCl. Both strains oxidized hydrogen, sulfide, various organic acids, and aromatics, such as benzoate and phenylacetate, as electron donors coupled to oxygen, nitrate, and (per)chlorate or chlorate as electron acceptors. The draft genome of strain CUZ carried the requisite (per)chlorate reduction island (PRI) for (per)chlorate respiration, while that of strain NSS carried the composite chlorate reduction transposon responsible for chlorate metabolism. The PRI of strain CUZ encoded a perchlorate reductase (Pcr), which reduced both perchlorate and chlorate, while the genome of strain NSS included a gene for a distinct chlorate reductase (Clr) that reduced only chlorate. When both (per)chlorate and nitrate were present, (per)chlorate was preferentially utilized if the inoculum was pregrown on (per)chlorate. Historically, (per)chlorate-reducing bacteria (PRB) and chlorate-reducing bacteria (CRB) have been isolated primarily from freshwater, mesophilic environments. This study describes the isolation and characterization of two highly related marine halophiles, one a PRB and the other a CRB, and thus broadens the known phylogenetic and physiological diversity of these unusual metabolisms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Sodium chlorate reduces presence of Escherichia coli in feces of lambs and ewes managed in shed-lambing systems

USDA-ARS?s Scientific Manuscript database

Our objective was to establish doses of orally-administered NaClO3 that reduced presence of generic Escherichia coli in intestines of ewes and neonatal lambs managed in a shed-lambing system. Neonatal lambs (n = 32; age = 7.1 ± 1.2 d; BW = 6.8 ± 1.0 kg) and yearling ewes (n = 44; BW = 74.8 ± 5.6 kg)...

Paper-Based Electrochemical Detection of Chlorate

PubMed Central

Shriver-Lake, Lisa C.; Zabetakis, Dan; Dressick, Walter J.; Stenger, David A.; Trammell, Scott A.

2018-01-01

We describe the use of a paper-based probe impregnated with a vanadium-containing polyoxometalate anion, [PMo11VO40]5−, on screen-printed carbon electrodes for the electrochemical determination of chlorate. Cyclic voltammetry (CV) and chronocoulometry were used to characterize the ClO3− response in a pH = 2.5 solution of 100 mM sodium acetate. A linear CV current response was observed between 0.156 and 1.25 mg/mL with a detection limit of 0.083 mg/mL (S/N > 3). This performance was reproducible using [PMo11VO40]5−-impregnated filter paper stored under ambient conditions for as long as 8 months prior to use. At high concentration of chlorate, an additional catalytic cathodic peak was seen in the reverse scan of the CVs, which was digitally simulated using a simple model. For chronocoulometry, the charge measured after 5 min gave a linear response from 0.625 to 2.5 mg/mL with a detection limit of 0.31 mg/mL (S/N > 3). In addition, the slope of charge vs. time also gave a linear response. In this case the linear range was from 0.312 to 2.5 mg/mL with a detection limit of 0.15 mg/mL (S/N > 3). Simple assays were conducted using three types of soil, and recovery measurements reported. PMID:29364153

Direct injection ion chromatography for the control of chlorinated drinking water: simultaneous estimation of nine haloacetic acids and quantitation of bromate, chlorite and chlorate along with the major inorganic anions.

PubMed

Garcia-Villanova, Rafael J; Raposo Funcia, César; Oliveira Dantas Leite, M Vilani; Toruño Fonseca, Ivania M; Espinosa Nieto, Miguel; Espuelas India, Javier

2014-09-01

Most methods for the analysis of haloacetic acids published in recent years are based on ion chromatography with direct injection, employing a gradient elution with potassium hydroxide (KOH). This work reports the exploration of an alternative eluent, a buffer of sodium carbonate/sodium hydrogen carbonate, aimed at the simultaneous analysis of nine haloacetic acids along with bromate, chlorite and chlorate. The alternative of both a less alkaline eluent and a lower temperature of operation may prevent the partial decomposition of some of the haloacetic acids during the analytical process, especially the more vulnerable brominated ones. Gradient elution at temperature of 7 °C yielded the best results, with an acceptable separation of 17 analytes (which includes the major natural inorganic anions) and a good linearity. Precision ranges from 0.3 to 23.4 (% V.C.), and detection limits are within units of μg L⁻¹, except for tribromoacetic acid - somewhat high in comparison with those of the official methods. Nonetheless, with the basic instrumentation setup herein described, this method may be suitable for monitoring when the drinking water treatments are to be optimized. This is especially interesting for small communities or for developing/developed countries in which regulations on disinfection by-products others than trihalomethanes are being addressed.

Sulfation of LH Does Not Affect Intracellular Trafficking

PubMed Central

Pearl, Christopher A.; Boime, Irving

2009-01-01

LH and FSH are produced by the same gonadotrope cells of the anterior pituitary but differ in their mode of secretion. LH secretion is primarily episodic, or regulated, while FSH secretion is primarily basal, or constitutive. The asparagine (N)-linked oligosaccharides of LH and FSH terminate with sulfate and sialic acid, respectively. TSH also contains sulfated N-linked oligosaccharides and is secreted through the regulated pathway. It has been hypothesized that sulfate plays a role in segregating LH to the regulated pathway. Using a mouse pituitary model, we tested this hypothesis by examining the secretory fate of LH from pituitaries treated with sodium chlorate, a known inhibitor of sulfation. Here we show that mouse LH is sulfated and secreted through the regulated pathway, while FSH is secreted constitutively. LH secretion from chlorate treated pituitaries, which showed complete inhibition of sulfation, was similar to untreated pituitaries. These data suggest that the metabolic role for sulfated N-linked oligosaccharides is not for intracellular trafficking but for the extracellular bioactivity of LH. PMID:19647136

Effect of various electrolytes upon cardiac and skeletal musculature

PubMed Central

Selye, H.; Bajusz, E.

1959-01-01

In rats kept on a low-potassium diet that contains only maintenance levels of magnesium, cardiac necroses and muscular cramps were readily induced by the oral administration of sodium perchlorate or disodium hydrogen phosphate. The precipitation of these cardiac and skeletal muscle changes by sodium chlorate was prevented by the prophylactic administration of either potassium or magnesium chlorides. The protective effect of these chlorides against the cardiotoxic and convulsive effects of disodium hydrogen phosphate has already been demonstrated by our earlier experiments. Sodium sulphate produced cardiac necroses in rats maintained on the same diet, and both potassium and magnesium chlorides had a prophylactic action. Unlike sodium perchlorate, however, sodium sulphate produced no muscular cramps under these conditions. Equimolecular amounts of sodium given in the form of sodium chloride (instead of sodium perchlorate, sodium sulphate, or disodium hydrogen phosphate) did not cause cardiac necroses or muscular cramps in rats maintained on the potassium-deficient diet. As the same three sodium salts, namely the perchlorate, the sulphate, and the hydrogen phosphate, produced cardiac necroses in rats sensitized by either a potassium-deficient diet or by certain corticoids, it seems that the anion must play a decisive rôle, since equivalent amounts of NaCl are ineffective. PMID:13651583

New considerations on hydrogen peroxide and related substances as food additives in view of carcinogenicity.

PubMed

Ito, R

1982-01-01

The use of hydrogen peroxide as a labile and safe food preservative in fish cake and boiled noodles has recently been restricted by the Japanese government, since hyperplasia has been found in the duodenum of mice after long-term peroral study. The action of compounds with resembling mode of action, potassium bromate as an improving agent in bread, and sodium chlorate as a weed killer are discussed in this paper in view of developmental and environmental pharmacology.

Improved Medium for Selecting Nitrate-Nonutilizing (nit) Mutants of Verticillium dahliae.

PubMed

Korolev, N; Katan, T

1997-10-01

ABSTRACT Nitrate-nonutilizing (nit) mutants are commonly used to determine vegetative compatibility between isolates of Verticillium dahliae by complementation (heterokaryon) testing. These mutants emerge spontaneously as chlorate-resistant sectors growing out of partially restricted, wild-type colonies on chlorate-amended media. The commonly used chlorate media are based on minimal medium (MMC) or cornmeal agar (CMC), amended with potassium chlorate. nit mutants recovered on these media constituted 10 to 36%(on MMC) and 25 to 45%(on CMC) of the apparently resistant sectors. An improved water agar chlorate medium (WAC) is described that is more effective for selecting chlorate-resistant nit mutants. WAC medium consists of agar (2%), glucose (0.02%), and potassium chlorate (2 to 5%). On WAC, growth of most V. dahliae isolates was strongly inhibited, and 66 to 100%(average >80%) of the chlorate-resistant sectors formed were nit mutants. Most mutants were characterized as nit1, and about 6% as NitM.

Why chlorate occurs in potable water and processed foods: a critical assessment and challenges faced by the food industry.

PubMed

Kettlitz, Beate; Kemendi, Gabriella; Thorgrimsson, Nigel; Cattoor, Nele; Verzegnassi, Ludovica; Le Bail-Collet, Yves; Maphosa, Farai; Perrichet, Aurélie; Christall, Birgit; Stadler, Richard H

2016-06-01

Recently, reports have been published on the occurrence of chlorate mainly in fruits and vegetables. Chlorate is a by-product of chlorinating agents used to disinfect water, and can be expected to be found in varying concentrations in drinking water. Data on potable water taken at 39 sampling points across Europe showed chlorate to range from < 0.003 to 0.803 mg l(-1) with a mean of 0.145 mg l(-1). Chlorate, however, can also be used as a pesticide, but authorisation was withdrawn in the European Union (EU), resulting in a default maximum residue limit (MRL) for foods of 0.01 mg kg(-1). This default MRL has now led to significant problems in the EU, where routinely disinfected water, used in the preparation of food products such as vegetables or fruits, leaves chlorate residues in excess of the default MRL, and in strict legal terms renders the food unmarketable. Due to the paucity of data on the chlorate content of prepared foods in general, we collated chlorate data on more than 3400 samples of mainly prepared foods, including dairy products, meats, fruits, vegetables and different food ingredients/additives. In total, 50.5% of the food samples contained chlorate above 0.01 mg kg(-1), albeit not due to the use of chlorate as a pesticide but mainly due to the occurrence of chlorate as an unavoidable disinfectant by-product. A further entry point of chlorate into foods may be via additives/ingredients that may contain chlorate as a by-product of the manufacturing process (e.g. electrolysis). Of the positive samples in this study, 22.4% revealed chlorate above 0.1 mg kg(-1). In the absence of EU levels for chlorate in water, any future EU regulations must consider the already available WHO guideline value of 0.7 mg l(-1) in potable water, and the continued importance of the usage of oxyhalides for disinfection purposes.

Chlorate adsorption from chlor-alkali plant brine stream.

PubMed

Lakshmanan, Shyam; Murugesan, Thanabalan

2017-07-01

Chlorates are present in the brine stream purged from chlor-alkali plants. Tests were conducted using activated carbon from coconut shell, coal or palm kernel shell to adsorb chlorate. The results show varying levels of adsorption with reduction ranging between 1.3 g/L and 1.8 g/L. This was higher than the chlorate generation rate of that plant, recorded at 1.22 g/L, indicating that chlorate can be adequately removed by adsorption using activated carbon. Coconut based activated carbon exhibited the best adsorption of chlorate of the three types of activated carbon tested. Introducing an adsorption step prior to purging of the brine will be able to reduce chlorate content in the brine stream. The best location for introducing the adsorption step was identified to be after dechlorination of the brine and before resaturation. Introduction of such an adsorption step will enable complete recovery of the brine and prevent brine purging, which in turn will result in less release of chlorides and chlorates to the environment.

Chlorate reductase is cotranscribed with cytochrome c and other downstream genes in the gene cluster for chlorate respiration of Ideonella dechloratans.

PubMed

Hellberg Lindqvist, Miriam; Nilsson, Thomas; Sundin, Pontus; Rova, Maria

2015-03-01

The chlorate-respiring bacterium Ideonella dechloratans is a facultative anaerobe that can use both oxygen and chlorate as terminal electron acceptors. The genes for the enzymes chlorate reductase (clrABDC) and chlorite dismutase, necessary for chlorate metabolism and probably acquired by lateral gene transfer, are located in a gene cluster that also includes other genes potentially important for chlorate metabolism. Among those are a gene for cytochrome c (cyc) whose gene product may serve as an electron carrier during chlorate reduction, a cofactor biosynthesis gene (mobB) and a predicted transcriptional regulator (arsR). Only chlorate reductase and chlorite dismutase have been shown to be expressed in vivo. Here, we report the in vivo production of a single polycistronic transcript covering eight open reading frames including clrABDC, cyc, mobB and arsR. Transcription levels of the cyc and clrA genes were compared to each other by the use of qRT-PCR in RNA preparations from cells grown under aerobic or chlorate reducing anaerobic conditions. The two genes showed the same mRNA levels under both growth regimes, indicating that no transcription termination occurs between them. Higher transcription levels were observed at growth without external oxygen supply. Implications for electron pathway integration following lateral gene transfer are discussed. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Synthetic and Evolutionary Construction of a Chlorate-Reducing Shewanella oneidensis MR-1

PubMed Central

Clark, Iain C.; Melnyk, Ryan A.; Youngblut, Matthew D.; Carlson, Hans K.; Iavarone, Anthony T.

2015-01-01

ABSTRACT Despite evidence for the prevalence of horizontal gene transfer of respiratory genes, little is known about how pathways functionally integrate within new hosts. One example of a mobile respiratory metabolism is bacterial chlorate reduction, which is frequently encoded on composite transposons. This implies that the essential components of the metabolism are encoded on these mobile elements. To test this, we heterologously expressed genes for chlorate reduction from Shewanella algae ACDC in the non-chlorate-reducing Shewanella oneidensis MR-1. The construct that ultimately endowed robust growth on chlorate included cld, a cytochrome c gene, clrABDC, and two genes of unknown function. Although strain MR-1 was unable to grow on chlorate after initial insertion of these genes into the chromosome, 11 derived strains capable of chlorate respiration were obtained through adaptive evolution. Genome resequencing indicated that all of the evolved chlorate-reducing strains replicated a large genomic region containing chlorate reduction genes. Contraction in copy number and loss of the ability to reduce chlorate were also observed, indicating that this phenomenon was extremely dynamic. Although most strains contained more than six copies of the replicated region, a single strain with less duplication also grew rapidly. This strain contained three additional mutations that we hypothesized compensated for the low copy number. We remade the mutations combinatorially in the unevolved strain and determined that a single nucleotide polymorphism (SNP) upstream of cld enabled growth on chlorate and was epistatic to a second base pair change in the NarP binding sequence between narQP and nrfA that enhanced growth. PMID:25991681

Single Crystal Membranes

NASA Technical Reports Server (NTRS)

Stormont, R. W.; Morrison, A.

1974-01-01

Single crystal a- and c-axis tubes and ribbons of sodium beta-alumina and sodium magnesium beta-alumina were grown from sodium oxide rich melts. Additional experiments grew ribbon crystals containing sodium magnesium beta, beta double prime, beta triple prime, and beta quadruple prime. A high pressure crystal growth chamber, sodium oxide rich melts, and iridium for all surfaces in contact with the melt were combined with the edge-defined, film-fed growth technique to grow the single crystal beta-alumina tubes and ribbons. The crystals were characterized using metallographic and X-ray diffraction techniques, and wet chemical analysis was used to determine the sodium, magnesium, and aluminum content of the grown crystals.

3-{[(E)-(2-Hydroxynaphthalen-1-yl)methylidene]amino}pyridinium per­chlorate

PubMed Central

Damous, Maamar; Dénès, George; Bouacida, Sofiane; Hamlaoui, Meriem; Merazig, Hocine; Daran, Jean-Claude

2013-01-01

In the title Schiff base salt, C16H13N2O+·ClO4 −, the pyridine ring and the naphthalene ring system are approximately co-planar [making a dihedral angle of 6.05 (12)°] and an intra­molecular O—H⋯N hydrogen bond occurs between the hydroxyl and imino groups. In the crystal, the cations and anions are linked by N—H⋯O and weak C—H⋯O hydrogen bonds, forming the supra­molecular layers parallel to (100). The crystal studied was an inversion twin refined with minor component = 0.43 (13). PMID:24427084

Nucleation and chiral symmetry breaking under controlled hydrodynamic flows

NASA Technical Reports Server (NTRS)

Wu, Xiao-Lun; Martin, Brian; Tharrington, Arnold

1994-01-01

The effects of hydrodynamic convection on nucleation and broken chiral symmetry have been investigated for a simple inorganic molecule, sodium chlorate (NaClO3). Our experiment suggests that the symmetry breaking is a result of hydrodynamic amplification of rare nucleation events. The effect is more pronounced when the primary nucleation occurs on the solute-vapor interface, where mixing in the surface sublayer becomes important. The transition from the achiral to the chiral states appears to be smooth as the hydrodynamic parameters, such as flow rate, are varied.

Synthetic and Evolutionary Construction of a Chlorate-Reducing Shewanella oneidensis MR-1.

PubMed

Clark, Iain C; Melnyk, Ryan A; Youngblut, Matthew D; Carlson, Hans K; Iavarone, Anthony T; Coates, John D

2015-05-19

Despite evidence for the prevalence of horizontal gene transfer of respiratory genes, little is known about how pathways functionally integrate within new hosts. One example of a mobile respiratory metabolism is bacterial chlorate reduction, which is frequently encoded on composite transposons. This implies that the essential components of the metabolism are encoded on these mobile elements. To test this, we heterologously expressed genes for chlorate reduction from Shewanella algae ACDC in the non-chlorate-reducing Shewanella oneidensis MR-1. The construct that ultimately endowed robust growth on chlorate included cld, a cytochrome c gene, clrABDC, and two genes of unknown function. Although strain MR-1 was unable to grow on chlorate after initial insertion of these genes into the chromosome, 11 derived strains capable of chlorate respiration were obtained through adaptive evolution. Genome resequencing indicated that all of the evolved chlorate-reducing strains replicated a large genomic region containing chlorate reduction genes. Contraction in copy number and loss of the ability to reduce chlorate were also observed, indicating that this phenomenon was extremely dynamic. Although most strains contained more than six copies of the replicated region, a single strain with less duplication also grew rapidly. This strain contained three additional mutations that we hypothesized compensated for the low copy number. We remade the mutations combinatorially in the unevolved strain and determined that a single nucleotide polymorphism (SNP) upstream of cld enabled growth on chlorate and was epistatic to a second base pair change in the NarP binding sequence between narQP and nrfA that enhanced growth. The ability of chlorate reduction composite transposons to form functional metabolisms after transfer to a new host is an important part of their propagation. To study this phenomenon, we engineered Shewanella oneidensis MR-1 into a chlorate reducer. We defined a set of genes sufficient to endow growth on chlorate from a plasmid, but found that chromosomal insertion of these genes was nonfunctional. Evolution of this inoperative strain into a chlorate reducer showed that tandem duplication was a dominant mechanism of activation. While copy number changes are a relatively rapid way of increasing gene dosage, replicating almost 1 megabase of extra DNA is costly. Mutations that alleviate the need for high copy number are expected to arise and eventually predominate, and we identified a single nucleotide polymorphism (SNP) that relieved the copy number requirement. This study uses both rational and evolutionary approaches to gain insight into the evolution of a fascinating respiratory metabolism. Copyright © 2015 Clark et al.

Possible potassium chlorate nephrotoxicity associated with chronic matchstick ingestion.

PubMed

Thurlow, John S; Little, Dustin J; Baker, Thomas P; Yuan, Christina M

2013-06-01

We present a case of a 48-year-old active duty male soldier with a history of chronic exposure to potassium chlorate, later diagnosed with chronic interstitial nephritis. He reported regular matchstick consumption to prevent chigger (Trombicula autumnalis) bites, amounting to ∼5.8 g of potassium chlorate over 3 years. Potassium chlorate can cause anuric renal failure within days of a toxic dose. Its slow excretion and mechanism of action suggest that renal toxicity may result from lower-dose chronic exposure. This case represents possible sequelae of chronic potassium chlorate ingestion.

Possible potassium chlorate nephrotoxicity associated with chronic matchstick ingestion*

PubMed Central

Thurlow, John S.; Little, Dustin J.; Baker, Thomas P.; Yuan, Christina M.

2013-01-01

We present a case of a 48-year-old active duty male soldier with a history of chronic exposure to potassium chlorate, later diagnosed with chronic interstitial nephritis. He reported regular matchstick consumption to prevent chigger (Trombicula autumnalis) bites, amounting to ∼5.8 g of potassium chlorate over 3 years. Potassium chlorate can cause anuric renal failure within days of a toxic dose. Its slow excretion and mechanism of action suggest that renal toxicity may result from lower-dose chronic exposure. This case represents possible sequelae of chronic potassium chlorate ingestion. PMID:26064493

Structure and Evolution of Chlorate Reduction Composite Transposons

PubMed Central

Clark, Iain C.; Melnyk, Ryan A.; Engelbrektson, Anna; Coates, John D.

2013-01-01

ABSTRACT The genes for chlorate reduction in six bacterial strains were analyzed in order to gain insight into the metabolism. A newly isolated chlorate-reducing bacterium (Shewanella algae ACDC) and three previously isolated strains (Ideonella dechloratans, Pseudomonas sp. strain PK, and Dechloromarinus chlorophilus NSS) were genome sequenced and compared to published sequences (Alicycliphilus denitrificans BC plasmid pALIDE01 and Pseudomonas chloritidismutans AW-1). De novo assembly of genomes failed to join regions adjacent to genes involved in chlorate reduction, suggesting the presence of repeat regions. Using a bioinformatics approach and finishing PCRs to connect fragmented contigs, we discovered that chlorate reduction genes are flanked by insertion sequences, forming composite transposons in all four newly sequenced strains. These insertion sequences delineate regions with the potential to move horizontally and define a set of genes that may be important for chlorate reduction. In addition to core metabolic components, we have highlighted several such genes through comparative analysis and visualization. Phylogenetic analysis places chlorate reductase within a functionally diverse clade of type II dimethyl sulfoxide (DMSO) reductases, part of a larger family of enzymes with reactivity toward chlorate. Nucleotide-level forensics of regions surrounding chlorite dismutase (cld), as well as its phylogenetic clustering in a betaproteobacterial Cld clade, indicate that cld has been mobilized at least once from a perchlorate reducer to build chlorate respiration. PMID:23919996

Biotechnological Applications of Microbial (Per)chlorate Reduction.

PubMed

Wang, Ouwei; Coates, John D

2017-11-24

While the microbial degradation of a chloroxyanion-based herbicide was first observed nearly ninety years ago, only recently have researchers elucidated the underlying mechanisms of perchlorate and chlorate [collectively, (per)chlorate] respiration. Although the obvious application of these metabolisms lies in the bioremediation and attenuation of (per)chlorate in contaminated environments, a diversity of alternative and innovative biotechnological applications has been proposed based on the unique metabolic abilities of dissimilatory (per)chlorate-reducing bacteria (DPRB). This is fueled in part by the unique ability of these organisms to generate molecular oxygen as a transient intermediate of the central pathway of (per)chlorate respiration. This ability, along with other novel aspects of the metabolism, have resulted in a wide and disparate range of potential biotechnological applications being proposed, including enzymatic perchlorate detection; gas gangrene therapy; enhanced xenobiotic bioremediation; oil reservoir bio-souring control; chemostat hygiene control; aeration enhancement in industrial bioreactors; and, biogenic oxygen production for planetary exploration. While previous reviews focus on the fundamental science of microbial (per)chlorate reduction (for example see Youngblut et al., 2016), here, we provide an overview of the emerging biotechnological applications of (per)chlorate respiration and the underlying organisms and enzymes to environmental and biotechnological industries.

(Per)chlorate in Biology on Earth and Beyond.

PubMed

Youngblut, Matthew D; Wang, Ouwei; Barnum, Tyler P; Coates, John D

2016-09-08

Respiration of perchlorate and chlorate [collectively, (per)chlorate] was only recognized in the last 20 years, yet substantial advances have been made in our understanding of the underlying metabolisms. Although it was once considered solely anthropogenic, pervasive natural sources, both terrestrial and extraterrestrial, indicate an ancient (per)chlorate presence across our solar system. These discoveries stimulated interest in (per)chlorate microbiology, and the application of advanced approaches highlights exciting new facets. Forward and reverse genetics revealed new information regarding underlying molecular biology and associated regulatory mechanisms. Structural and functional analysis characterized core enzymes and identified novel reaction sequences. Comparative genomics elucidated evolutionary aspects, and stress analysis identified novel response mechanisms to reactive chlorine species. Finally, systems biology identified unique metabolic versatility and novel mechanisms of (per)chlorate respiration, including symbiosis and a hybrid enzymatic-abiotic metabolism. While many published studies focus on (per)chlorate and their basic metabolism, this review highlights seminal advances made over the last decade and identifies new directions and potential novel applications.

The Nitrate/(Per)Chlorate Relationship on Mars

NASA Technical Reports Server (NTRS)

Stern, Jennifer C.; Sutter, Brad; Jackson, W. Andrew; Navarro-Gonzalez, Rafael; McKay, Christopher P.; Ming, Douglas W.; Archer, P. Douglas; Mahaffy, Paul R.

2017-01-01

Nitrate was recently detected in Gale Crater sediments on Mars at abundances up to approximately 600 mg/kg, confirming predictions of its presence at abundances consistent with models based on impact-generated nitrate and other sources of fixed nitrogen. Terrestrial Mars analogs, Mars meteorites, and other solar system materials help establish a context for interpreting in situ nitrate measurements on Mars, particularly in relation to other cooccuring salts. We compare the relative abundance of nitrates to oxychlorine (chlorate and/or perchlorate, hereafter (per)chlorate) salts on Mars and Earth. The nitrate/(per)chlorate ratio on Mars is greater than 1, significantly lower than on Earth (nitrate/(per)chlorate greater than 10(exp.3)), suggesting not only the absence of biological activity but also different (per)chlorate formation mechanisms on Mars than on Earth.

Investigation of crystallization kinetics of sodium bicarbonate in a continuous stirred tank crystallizer

NASA Astrophysics Data System (ADS)

Zhu, Yi; Haut, Benoît; Halloin, Veronique; Delplancke-Ogletree, Marie-Paule

2005-08-01

In our previous work [J. Crystal Growth 263 (2004) 459], a supersaturation determination method using a high-precision densimeter was designed and developed for monitoring sodium bicarbonate supersaturation in the sodium carbonate-bicarbonate system, a two-component solution in equilibrium. In the present paper, we apply this method to the study of sodium bicarbonate continuous crystallization. It gives us access to the sodium bicarbonate supersaturation evolution. The sodium bicarbonate supersaturation evolution and their crystallization kinetics obtained in a continuous stirred tank crystallizer are investigated under different operational conditions, such as residence time, initial supersaturation and seeding. The induction time determined by density measurements is discussed. Mathematical modeling is used to interpret the supersaturation evolution. It is shown that measuring the density gives satisfying performances for studying the crystallization of a two-component solution in equilibrium, such as the sodium carbonate-bicarbonate system.

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

PubMed Central

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- and perchlorate-reducing activity. The oxygen-sensitive enzyme was located in the periplasm and had an apparent molecular mass of 420 kDa, with subunits of 95 and 40 kDa in an α3β3 composition. Metal analysis showed the presence of 11 mol of iron, 1 mol of molybdenum, and 1 mol of selenium per mol of heterodimer. In accordance, quantitative electron paramagnetic resonance spectroscopy showed the presence of one [3Fe-4S] cluster and two [4Fe-4S] clusters. Furthermore, two different signals were ascribed to Mo(V). The Kmvalues for perchlorate and chlorate were 27 and <5 μM, respectively. Besides perchlorate and chlorate, nitrate, iodate, and bromate were also reduced at considerable rates. The resemblance of the enzyme to nitrate reductases, formate dehydrogenases, and selenate reductase is discussed. PMID:10542172

Adsorption performance of coconut shell activated carbon for the removal of chlorate from chlor-alkali brine stream.

PubMed

Lakshmanan, Shyam; Murugesan, Thanapalan

2016-12-01

Activated carbon from coconut shell was used to investigate the adsorption of chlorate from a chlor-alkali plant's brine stream. The effect of pH, flowrate, chlorate and chloride concentration on the breakthrough curves were studied in small-scale column trials. The results obtained show enhanced adsorption at low flowrates, higher chlorate concentrations, and at a pH of 10. These studies show that introducing an activated carbon adsorption column just before the saturator would remove sufficient quantities of chlorate to allow more of the chlor-alkali plant's brine stream to be reused. From column dynamic studies, the Thomas model showed close approximation when the chlorate in the effluent was higher than breakthrough concentrations and there was close correlation at high influent concentration. The q o (maximum adsorption capacity) values were close to those obtained experimentally, indicating close representation of the breakthrough curve by the Thomas model.

Mechanisms of direct inhibition of the respiratory sulfate-reduction pathway by (per)chlorate and nitrate.

PubMed

Carlson, Hans K; Kuehl, Jennifer V; Hazra, Amrita B; Justice, Nicholas B; Stoeva, Magdalena K; Sczesnak, Andrew; Mullan, Mark R; Iavarone, Anthony T; Engelbrektson, Anna; Price, Morgan N; Deutschbauer, Adam M; Arkin, Adam P; Coates, John D

2015-06-01

We investigated perchlorate (ClO(4)(-)) and chlorate (ClO(3)(-)) (collectively (per)chlorate) in comparison with nitrate as potential inhibitors of sulfide (H(2)S) production by mesophilic sulfate-reducing microorganisms (SRMs). We demonstrate the specificity and potency of (per)chlorate as direct SRM inhibitors in both pure cultures and undefined sulfidogenic communities. We demonstrate that (per)chlorate and nitrate are antagonistic inhibitors and resistance is cross-inducible implying that these compounds share at least one common mechanism of resistance. Using tagged-transposon pools we identified genes responsible for sensitivity and resistance in Desulfovibrio alaskensis G20. We found that mutants in Dde_2702 (Rex), a repressor of the central sulfate-reduction pathway were resistant to both (per)chlorate and nitrate. In general, Rex derepresses its regulon in response to increasing intracellular NADH:NAD(+) ratios. In cells in which respiratory sulfate reduction is inhibited, NADH:NAD(+) ratios should increase leading to derepression of the sulfate-reduction pathway. In support of this, in (per)chlorate or nitrate-stressed wild-type G20 we observed higher NADH:NAD(+) ratios, increased transcripts and increased peptide counts for genes in the core Rex regulon. We conclude that one mode of (per)chlorate and nitrate toxicity is as direct inhibitors of the central sulfate-reduction pathway. Our results demonstrate that (per)chlorate are more potent inhibitors than nitrate in both pure cultures and communities, implying that they represent an attractive alternative for controlling sulfidogenesis in industrial ecosystems. Of these, perchlorate offers better application logistics because of its inhibitory potency, solubility, relative chemical stability, low affinity for mineral cations and high mobility in environmental systems.

Highly selective direct determination of chlorate ions by using a newly developed potentiometric electrode based on modified smectite.

PubMed

Topcu, Cihan

2016-12-01

A novel polyvinyl chloride membrane chlorate (ClO 3 - ) selective electrode based on modified smectite was developed for the direct determination of chlorate ions and the potentiometric performance characteristics of its were examined. The best selectivity and sensitivity for chlorate ions were obtained for the electrode membrane containing ionophore/polyvinylchloride/o-nitrophenyloctylether in composition of 12/28/60 (w/w%). The proposed electrode showed a Nernstian response toward chlorate ions at pH=7 in the concentration range of 1×10 -7 -1×10 -1 M and the limit of detection was calculated as 9×10 -8 M from the constructed response plot. The linear slope of the electrode was -61±1mVdecade -1 for chlorate activity in the mentioned linear working range. The selectivity coefficients were calculated according to both the matched potential method and the separate solution method. The calculated selectivity coefficients showed that the electrode performed excellent selectivity for chlorate ions. The potentiometric response of electrode toward chlorate ions was found to be highly reproducible. The electrode potential was stable between pH=4-10 and it had a dynamic response time of <5s. The potentiometric behavior of the electrode in partial non-aqueous medium was also investigated and the obtained results (up to 5% (v/v) alcohol) were satisfactory. The proposed electrode was used during 15 weeks without any significant change in its potential response. Additionally, the electrode was very useful in water analysis studies such as dam water, river water, tap water, and swimming pool water where the direct determination of chlorate ions was required. Copyright © 2016 Elsevier B.V. All rights reserved.

Toxic effects of chlorate on three plant species inoculated with arbuscular mycorrhizal fungi.

PubMed

Li, Huashou; Zhang, Xiuyu; Lin, Chuxia; Wu, Qitang

2008-11-01

Pot experiments were conducted to examine the toxic effects of chlorate on bermudagrass, bahiagrass, and longan seedling with a focus on arbuscular mycorrhizal fungi-plant associations. The results show that application of chlorate could cause slight soil acidification, but the resulting pH was still around 5.5, which is unlikely to adversely affect plant growth. Increase in the application rate of chlorate resulted in a decrease in colonization rate of arbuscular mycorrhizal fungi in plant roots, P uptake by the plants and plant biomass. This appears to suggest that the reduction in plant growth may be related to impeded uptake of P by the plants due to the failure of the plants to form sufficient mycorrhizal associations when chlorate is in sufficient amounts to cause toxicity to arbuscular mycorrhizal fungi. Under the experimental conditions set for this study, bermudagrass suffered from stronger chlorate stress than bahiagrass and longan seedling did in terms of plant-arbuscular mycorrhizal fungi (AMF) symbiosis development.

Bacterial growth tolerance to concentrations of chlorate and perchlorate salts relevant to Mars

NASA Astrophysics Data System (ADS)

Al Soudi, Amer F.; Farhat, Omar; Chen, Fei; Clark, Benton C.; Schneegurt, Mark A.

2017-07-01

The Phoenix lander at Mars polar cap found appreciable levels of (per)chlorate salts, a mixture of perchlorate and chlorate salts of Ca, Fe, Mg and Na at levels of ~0.6% in regolith. These salts are highly hygroscopic and can form saturated brines through deliquescence, likely producing aqueous solutions with very low freezing points on Mars. To support planetary protection efforts, we have measured bacterial growth tolerance to (per)chlorate salts. Existing bacterial isolates from the Great Salt Plains of Oklahoma (NaCl-rich) and Hot Lake in Washington (MgSO4-rich) were tested in high concentrations of Mg, K and Na salts of chlorate and perchlorate. Strong growth was observed with nearly all of these salinotolerant isolates at 1% (~0.1 M) (per)chlorate salts, similar to concentrations observed in bulk soils on Mars. Growth in perchlorate salts was observed at concentrations of at least 10% (~1.0 M). Greater tolerance was observed for chlorate salts, where growth was observed to 2.75 M (>25%). Tolerance to K salts was greatest, followed by Mg salts and then Na salts. Tolerances varied among isolates, even among those within the same phylogenetic clade. Tolerant bacteria included genera that also are found in spacecraft assembly facilities. Substantial microbial tolerance to (per)chlorate salts is a concern for planetary protection since tolerant microbes contaminating spacecraft would have a greater chance for survival and proliferation, despite the harsh chemical conditions found near the surface of Mars.

A potential role for chondroitin sulfate/dermatan sulfate in arm regeneration in Amphiura filiformis.

PubMed

Ramachandra, Rashmi; Namburi, Ramesh B; Dupont, Sam T; Ortega-Martinez, Olga; van Kuppevelt, Toin H; Lindahl, Ulf; Spillmann, Dorothe

2017-05-01

Glycosaminoglycans (GAGs), such as chondroitin sulfate (CS) and dermatan sulfate (DS) from various vertebrate and invertebrate sources are known to be involved in diverse cellular mechanisms during repair and regenerative processes. Recently, we have identified CS/DS as the major GAG in the brittlestar Amphiura filiformis, with high proportions of di- and tri-O-sulfated disaccharide units. As this echinoderm is known for its exceptional regeneration capacity, we aimed to explore the role of these GAG chains during A. filiformis arm regeneration. Analysis of CS/DS chains during the regeneration process revealed an increase in the proportion of the tri-O-sulfated disaccharides. Conversely, treatment of A. filiformis with sodium chlorate, a potent inhibitor of sulfation reactions in GAG biosynthesis, resulted in a significant reduction in arm growth rates with total inhibition at concentrations higher than 5 mM. Differentiation was less impacted by sodium chlorate exposure or even slightly increased at 1-2 mM. Based on the structural changes observed during arm regeneration we identified chondroitin synthase, chondroitin-4-O-sulfotransferase 2 and dermatan-4-O-sulfotransferase as candidate genes and sought to correlate their expression with the expression of the A. filiformis orthologue of bone morphogenetic factors, AfBMP2/4. Quantitative amplification by real-time PCR indicated increased expression of chondroitin synthase and chondroitin-4-O-sulfotransferase 2, with a corresponding increase in AfBMP2/4 during regeneration relative to nonregenerating controls. Our findings suggest that proper sulfation of GAGs is important for A. filiformis arm regeneration and that these molecules may participate in mechanisms controlling cell proliferation. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Microbial redox processes in deep subsurface environments and the potential application of (per)chlorate in oil reservoirs

PubMed Central

Liebensteiner, Martin G.; Tsesmetzis, Nicolas; Stams, Alfons J. M.; Lomans, Bartholomeus P.

2014-01-01

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 (per)chlorate] reduction in oil reservoirs will be discussed. Special attention is given to elevated temperatures that are predominant in the deep subsurface. Microbial reduction of (per)chlorate is a thermodynamically favorable redox process, also at high temperature. However, knowledge about (per)chlorate 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 (meta)genome databases and combining this knowledge with extrapolations to earlier-made physiological observations we speculate on the potential of (per)chlorate reduction in the subsurface and more precisely oil fields. In addition, the application of (per)chlorate for bioremediation, souring control, and microbial enhanced oil recovery are addressed. PMID:25225493

RAPD cluster analysis and chlorate sensitivity of some Indian isolates of Macrophomina phaseolina from sorghum and their relationships with pathogenicity.

PubMed

Das, I K; Fakrudin, B; Arora, D K

2008-01-01

Charcoal rot caused by Macrophomina phaseolina is an economically important disease in sorghum grown during the post rainy season in India. Variations in random amplified polymorphic DNA (RAPD) polymorphisms, chlorate sensitivity and pathogenicity were studied among sorghum isolates of M. phaseolina collected from different parts of India. RAPD data based on 14 random primers of Kit A and C (OPA and OPC) on 20 isolates showed a high degree of polymorphism (98.1%) in different isolates. UPGMA dendrogram on RAPD data produced 7 clusters at the level of 37% similarity. Isolates from the same locations showed a tendency to group closer, substantiating closer genetic relatedness. Sorghum infecting Macrophomina isolates showed a mixed response for sensitivity to potassium chlorate (120 mM). Chlorate-resistant isolates were predominant (>65% of the isolates) over sensitive isolates. Chlorate-sensitive isolates were found to be genetically closer among them than the resistant ones. For the first time it was shown that chlorate sensitivity in Macrophomina had some relations with charcoal rot severity in sorghum.

Foliar fertilization as an alternative to hand thinning fruit in chlorate treated Dimocarpus longan Lour. trees in Hawaii.

USDA-ARS?s Scientific Manuscript database

Longan, Dimocarpus longan Lour, is a member of the Sapindaceae, a family that also includes lychee, and rambutan. The discovery of potassium chlorate (KClO3) induced flowering solved the problem of alternate bearing and enabled the grower to produce off-season longan. Chlorate treatments commonly i...

Chlorate origin and fate in shallow groundwater below agricultural landscapes.

PubMed

Mastrocicco, Micòl; Di Giuseppe, Dario; Vincenzi, Fabio; Colombani, Nicolò; Castaldelli, Giuseppe

2017-12-01

In agricultural lowland landscapes, intensive agricultural is accompanied by a wide use of agrochemical application, like pesticides and fertilizers. The latter often causes serious environmental threats such as N compounds leaching and surface water eutrophication; additionally, since perchlorate can be present as impurities in many fertilizers, the potential presence of perchlorates and their by-products like chlorates and chlorites in shallow groundwater could be a reason of concern. In this light, the present manuscript reports the first temporal and spatial variation of chlorates, chlorites and major anions concentrations in the shallow unconfined aquifer belonging to Ferrara province (in the Po River plain). The study was made in 56 different locations to obtain insight on groundwater chemical composition and its sediment matrix interactions. During the monitoring period from 2010 to 2011, in June 2011 a nonpoint pollution of chlorates was found in the shallow unconfined aquifer belonging to Ferrara province. Detected chlorates concentrations ranged between 0.01 and 38 mg/l with an average value of 2.9 mg/l. Chlorates were found in 49 wells out of 56 and in all types of lithology constituting the shallow aquifer. Chlorates concentrations appeared to be linked to NO 3 - , volatile fatty acids (VFA) and oxygen reduction potential (ORP) variations. Chlorates behaviour was related to the biodegradation of perchlorates, since perchlorates are favourable electron acceptors for the oxidation of labile dissolved organic carbon (DOC) in groundwater. Further studies must take into consideration to monitor ClO 4 - in pore waters and groundwater to better elucidate the mass flux of ClO 4 - in shallow aquifers belonging to agricultural landscapes. Copyright © 2017 Elsevier Ltd. All rights reserved.

(Per)Chlorate-Reducing Bacteria Can Utilize Aerobic and Anaerobic Pathways of Aromatic Degradation with (Per)Chlorate as an Electron Acceptor

PubMed Central

Carlström, Charlotte I.; Loutey, Dana; Bauer, Stefan; Clark, Iain C.; Rohde, Robert A.; Iavarone, Anthony T.; Lucas, Lauren

2015-01-01

ABSTRACT The pathways involved in aromatic compound oxidation under perchlorate and chlorate [collectively known as (per)chlorate]-reducing conditions are poorly understood. Previous studies suggest that these are oxygenase-dependent pathways involving O2 biogenically produced during (per)chlorate respiration. Recently, we described Sedimenticola selenatireducens CUZ and Dechloromarinus chlorophilus NSS, which oxidized phenylacetate and benzoate, two key intermediates in aromatic compound catabolism, coupled to the reduction of perchlorate or chlorate, respectively, and nitrate. While strain CUZ also oxidized benzoate and phenylacetate with oxygen as an electron acceptor, strain NSS oxidized only the latter, even at a very low oxygen concentration (1%, vol/vol). Strains CUZ and NSS contain similar genes for both the anaerobic and aerobic-hybrid pathways of benzoate and phenylacetate degradation; however, the key genes (paaABCD) encoding the epoxidase of the aerobic-hybrid phenylacetate pathway were not found in either genome. By using transcriptomics and proteomics, as well as by monitoring metabolic intermediates, we investigated the utilization of the anaerobic and aerobic-hybrid pathways on different electron acceptors. For strain CUZ, the results indicated utilization of the anaerobic pathways with perchlorate and nitrate as electron acceptors and of the aerobic-hybrid pathways in the presence of oxygen. In contrast, proteomic results suggest that strain NSS may use a combination of the anaerobic and aerobic-hybrid pathways when growing on phenylacetate with chlorate. Though microbial (per)chlorate reduction produces molecular oxygen through the dismutation of chlorite (ClO2−), this study demonstrates that anaerobic pathways for the degradation of aromatics can still be utilized by these novel organisms. PMID:25805732

Host Specialization in the Charcoal Rot Fungus, Macrophomina phaseolina.

PubMed

Su, G; Suh, S O; Schneider, R W; Russin, J S

2001-02-01

ABSTRACT To investigate host specialization in Macrophomina phaseolina, the fungus was isolated from soybean, corn, sorghum, and cotton root tissue and soil from fields cropped continuously to these species for 15 years in St. Joseph, LA. Chlorate phenotype of each isolate was determined after growing on a minimal medium containing 120 mM potassium chlorate. Consistent differences in chlorate sensitivity were detected among isolates from different hosts and from soil versus root. To further explore genetic differentiation among fungal isolates from each host, these isolates were examined by restriction fragment length polymorphism and random amplified polymorphic DNA (RAPD) analysis. No variations were observed among isolates in restriction patterns of DNA fragments amplified by polymerase chain reaction covering the internal transcribed spacer region, 5.8S rRNA and part of 25S rRNA, suggesting that M. phaseolina constitutes a single species. Ten random primers were used to amplify the total DNA of 45 isolates, and banding patterns resulting from RAPD analysis were compared with the neighbor-joining method. Isolates from a given host were genetically similar to each other but distinctly different from those from other hosts. Chlorate-sensitive isolates were distinct from chlorate-resistant isolates within a given host. In greenhouse tests, soybean, sorghum, corn, and cotton were grown separately in soil infested with individual isolates of M. phaseolina that were chosen based on their host of origin and chlorate phenotype. Root colonization and plant weight were measured after harvesting. More colonization of corn roots occurred when corn was grown in soil containing corn isolates compared with isolates from other hosts. However, there was no host specialization in isolates from soybean, sorghum, or cotton. More root colonization in soybean occurred with chlorate-sensitive than with chlorate-resistant isolates.

Isomers and energy landscapes of micro-hydrated sulfite and chlorate clusters

NASA Astrophysics Data System (ADS)

Hey, John C.; Doyle, Emily J.; Chen, Yuting; Johnston, Roy L.

2018-03-01

We present putative global minima for the micro-hydrated sulfite SO32-(H2O)N and chlorate ClO32(H2O)N systems in the range 3≤N≤15 found using basin-hopping global structure optimization with an empirical potential. We present a structural analysis of the hydration of a large number of minimized structures for hydrated sulfite and chlorate clusters in the range 3≤N≤50. We show that sulfite is a significantly stronger net acceptor of hydrogen bonding within water clusters than chlorate, completely suppressing the appearance of hydroxyl groups pointing out from the cluster surface (dangling OH bonds), in low-energy clusters. We also present a qualitative analysis of a highly explored energy landscape in the region of the global minimum of the eight water hydrated sulfite and chlorate systems. This article is part of the theme issue `Modern theoretical chemistry'.

Isomers and energy landscapes of micro-hydrated sulfite and chlorate clusters.

PubMed

Hey, John C; Doyle, Emily J; Chen, Yuting; Johnston, Roy L

2018-03-13

We present putative global minima for the micro-hydrated sulfite SO 3 2- (H 2 O) N and chlorate ClO 3 - (H 2 O) N systems in the range 3≤ N ≤15 found using basin-hopping global structure optimization with an empirical potential. We present a structural analysis of the hydration of a large number of minimized structures for hydrated sulfite and chlorate clusters in the range 3≤ N ≤50. We show that sulfite is a significantly stronger net acceptor of hydrogen bonding within water clusters than chlorate, completely suppressing the appearance of hydroxyl groups pointing out from the cluster surface (dangling OH bonds), in low-energy clusters. We also present a qualitative analysis of a highly explored energy landscape in the region of the global minimum of the eight water hydrated sulfite and chlorate systems.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Authors.

Clorate Metabolism in Pure Cultures of E.Coli 0157:H7 Pretreated with Either Nitrate or Chlorate

USDA-ARS?s Scientific Manuscript database

Experiments were conducted to determine the effects of 5, 7.5, and 10 mM nitrate, and 5, 10, or 20 mM chlorate on total E. coli counts, chlorate metabolism, and volatile fatty acid (VFA) concentrations in anaerobic ruminal fluid cultures. Nitrate did not affect total E. coli counts (P = 0.05), chlor...

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

NASA Technical Reports Server (NTRS)

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 HCl and oxygen releases within the same range as the Rock-nest windblown deposit, the Greenhorn eolian sandstone, and the John Klein drilled mudstone. Overall, mixtures of perchlorates or chlorates with saponite provide the first explanation for the high temperature HCl releases in addition to the oxygen releases observed in Gale Crater materials.

Peculiar Traits of Coarse AP

DTIC Science & Technology

2014-01-01

propellant. Since coarse AP in particles larger than about 150 microns are used in great majority for AP oxidized solid propellants, the nature of...Microscopic amounts of liquid containing water were contained in the reactive centers. The maximum size for reactive centers was reasoned to be...bond in the original chlorate ion. Oxygen atom swapping between chlorate and perchlorate ions would provide chlorate migration without use of forces

Chlorate Formation Mechanism in the Presence of Sulfate Radical, Chloride, Bromide and Natural Organic Matter.

PubMed

Hou, Shaodong; Ling, Li; Dionysiou, Dionysios D; Wang, Yuru; Huang, Jiajia; Guo, Kaiheng; Li, Xuchun; Fang, Jingyun

2018-06-05

Halides and natural organic matter (NOM) are inevitable in aquatic environment and influence the degradation of contaminants in sulfate radical (SO 4 •- )-based advanced oxidation processes. This study investigated the formation of chlorate in the coexposure of SO 4 •- , chloride (Cl - ), bromide (Br - ) and/or NOM in UV/persulfate (UV/PDS) and cobalt(II)/peroxymonosulfate (Co/PMS) systems. The formation of chlorate increased with increasing Cl - concentration in the UV/PDS system, however, in the Co/PMS system, it initially increased and then decreased. The chlorate formation involved the formation of hypochlorous acid/hypochlorite (HOCl/OCl - ) as an intermediate in both systems. The formation was primarily attributable to SO 4 •- in the UV/PDS system, whereas Co(III) played a significant role in the oxidation of Cl - to HOCl/OCl - and SO 4 •- was important for the oxidation of HOCl/OCl - to chlorate in the Co/PMS system. The pseudo-first-order rate constants ( k') of the transformation from Cl - to HOCl/OCl - were 3.32 × 10 -6 s -1 and 9.23 × 10 -3 s -1 in UV/PDS and Co/PMS, respectively. Meanwhile, k' of HOCl/OCl - to chlorate in UV/PDS and Co/PMS were 2.43 × 10 -3 s -1 and 2.70 × 10 -4 s -1 , respectively. Br - completely inhibited the chlorate formation in UV/PDS, but inhibited it by 45.2% in Co/PMS. The k' of SO 4 •- reacting with Br - to form hypobromous acid/hypobromite (HOBr/OBr - ) was calculated to be 378 times higher than that of Cl - to HOCl/OCl - , but the k' of Co(III) reacting with Br - to form HOBr/OBr - was comparable to that of Cl - to HOCl/OCl - . NOM also significantly inhibited the chlorate formation, due to the consumption of SO 4 •- and reactive chlorine species (RCS, such as Cl·, ClO· and HOCl/OCl - ). This study demonstrated the formation of chlorate in SO 4 •- -based AOPs, which should to be considered in their application in water treatment.

Development of single crystal membranes

NASA Technical Reports Server (NTRS)

Stormont, R. W.; Cocks, F. H.

1972-01-01

The design and construction of a high pressure crystal growth chamber was accomplished which would allow the growth of crystals under inert gas pressures of 2 MN/sq m (300 psi). A novel crystal growth technique called EFG was used to grow tubes and rods of the hollandite compounds, BaMgTi7O16, K2MgTi7O16, and tubes of sodium beta-alumina, sodium magnesium-alumina, and potassium beta-alumina. Rods and tubes grown are characterized using metallographic and X-ray diffraction techniques. The hollandite compounds are found to be two or three-phase, composed of coarse grained orientated crystallites. Single crystal c-axis tubes of sodium beta-alumina were grown from melts containing excess sodium oxide. Additional experiments demonstrated that crystals of magnesia doped beta-alumina and potassium beta-alumina also can be achieved by this EFG technique.

Study of linear optical parameters of sodium sulphide nano-particles added ADP crystals

NASA Astrophysics Data System (ADS)

Kochuparampil, A. P.; Joshi, J. H.; Dixit, K. P.; Jethva, H. O.; Joshi, M. J.

2017-05-01

Ammonium Dihydrogen Phosphate (ADP) is one of the nonlinear optical crystals. It is having various applications like optical mixing, electro-optical modulator, harmonic generators, etc. Chalcogenide compounds are poorly soluble in water and difficult to add in the water soluble ADP crystals. The solubility of Chalcogenide compounds can be increased by synthesizing the nano-structured samples with suitable capping agent. In the present study sodium sulphide was added in to ADP to modify its linear optical parameters. Sodium sulphide nano particles were synthesized by co-precipitation technique using Ethylene diamine as capping agent followed by microwave irradiation. The powder XRD confirmed the nano-structured nature of sodium sulphide nano particles. The solubility of nanoparticles of sodium sulphide increased significantly in water compared to the bulk. Pure and Na2S added ADP crystals were grown by slow solvent evaporation method at room temperature. The presence of sodium in ADP was confirmed by AAS. The UV-Vis spectra were recorded for all crystals. Various optical parameters like, transmittance, energy band gap, extinction coefficient, refractive index, optical conductivity, etc. were evaluated. The electronic polarizibility of pure and doped crystals calculated from energy band gap. The effect of doping concentration was found on various parameters.

Coulometrische titration von hypochloriten und chloraten.

PubMed

Gründler, P; Holzapfel, H

1970-03-01

Hypochlorite was determined by direct coulometric titration with iron(II) in an acetate buffered solution. Chlorate was titrated with titanium(III) in 2M hydrochloric acid. Amperometric indication with one and two electrodes, respectively, was used. Mixtures of hypochlorites and chlorates, e.g., in industrial electrolytes, may be analysed. On a déterminé l'hypochlorite par titrage coulométrique direct avec le fer(II) dans une solution tamponnée à l'acétate. On a titré le chlorate avec le titane(III) en acide chlorhydrique 2M. On a utilisé l'indication ampérométrique une et deux électrodes respectivement. On peut analyser des mélanges d'hypochlorites et de chlorates, par exemple dans des électrolytes industriels.

Infrared (1-12 μm) atomic and molecular emission signatures from energetic materials using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Kumi Barimah, E.; Hömmerich, U.; Brown, E.; Yang, C. S.-C.; Trivedi, S. B.; Jin, F.; Wijewarnasuriya, P. S.; Samuels, A. C.; Snyder, A. P.

2013-05-01

Laser-induced breakdown spectroscopy (LIBS) is a powerful analytical technique to detect the elemental composition of solids, liquids, and gases in real time. For example, recent advances in UV-VIS LIBS have shown great promise for applications in chemical, biological, and explosive sensing. The extension of conventional UVVIS LIBS to the near-IR (NIR), mid-IR (MIR) and long wave infrared (LWIR) regions (~1-12 μm) offers the potential to provide additional information due to IR atomic and molecular signatures. In this work, a Q-switched Nd: YAG laser operating at 1064 nm was employed as the excitation source and focused onto several chlorate and nitrate compounds including KClO3, NaClO3, KNO3, and NaNO3 to produce intense plasma at the target surface. IR LIBS studies on background air, KCl , and NaCl were also included for comparison. All potassium and sodium containing samples revealed narrow-band, atomic-like emissions assigned to transitions of neutral alkali-metal atoms in accordance with the NIST atomic spectra database. In addition, first evidence of broad-band molecular LIBS signatures from chlorate and nitrate compounds were observed at ~10 μm and ~7.3 μm, respectively. The observed molecular emissions showed strong correlation with FTIR absorption spectra of the investigated materials.

Identification of an anaerobic bacterium which reduces perchlorate and chlorate as Wolinella succinogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallace, W.; Attaway, H.

1995-12-31

Perchlorate and chlorate salts are widely used by the chemical, aerospace and defense industries as oxidizers in propellant, explosives and pyrotechnics. The authors have isolated a anaerobic bacterium which is capable of the dissimilatory reduction of both perchlorate and chlorate for energy and growth. Strain HAP-1 is a gram negative, thin rod, non-sporeforming, highly motile strict anaerobe. Antibiotic resistance profiles, utilization of carbon substrates and electron acceptors demonstrated similar physiological characteristics to Wolinella succinogenes. Pairwise comparisons of 16S RNA sequences showed only a 0.75% divergence between strain HAP-1 and W. succinogenes. Physiological, morphological and 16S RRNA sequence data indicate strainmore » HAP-1 is a subspecies of W. succinogenes that can utilize perchlorate and chlorate as terminal electron acceptors.« less

Wound isolate of Salmonella typhimurium that became chlorate resistant after exposure to Dakin's solution: concomitant loss of hydrogen sulfide production, gas production, and nitrate reduction.

PubMed Central

Lannigan, R; Hussain, Z

1993-01-01

A strain of Salmonella typhimurium isolated from a decubitus ulcer that was being treated topically with half-strength Dakin's solution became H2S negative, nitrate negative, and unable to produce gas from glucose. Experimental data suggested that these effects were associated with the development of chlorate resistance. Thirty-five other strains of Salmonella spp. that were made chlorate resistant also became negative for these three tests. PMID:8408574

Effect of molecular weight of polystyrensulfonic acid sodium salt polymers on the precipitation kinetics of sodium bicarbonate

NASA Astrophysics Data System (ADS)

Martínez-Cruz, Nancy; Carrillo-Romo, Felipe; Jaramillo-Vigueras, David

2004-10-01

This paper analyzes the effect of polystyrensulfonic acid sodium salt (NaPSS), obtained by kinetic precipitation from solutions of polymers of molecular weight 245 000 and 38 000 g mol-1 in sodium bicarbonate (NaHCO3) itself precipitated from synthetic brine. Crystal size, shape and the additive adsorbed are reported. X shaped and hexagonal prisms crystals with different aspect ratios were obtained. The results show that with increasing polymer concentration the crystal size decreases, from 0.27 to 0.48 mm. Additionally, the higher molecular weight polymer shows both higher adsorption capacity and higher crystal habit modification. Crystal shape patterns were similar for both polymers; however, the higher molecular weight material induced changes at lower concentration. It was observed that the precipitation rate reached a minimum with increasing additive concentration.

Studies on potassium chlorate as a primary oxidimetric reagent.

PubMed

Murty, C R; Rao, G G

1972-01-01

Conditions have been established for the use of potassium chlorate as a primary oxidizing agent in the direct titration of vanadium(III), tin(II) and titanium(III) with visual or potentiometric end-points.

A new system for sodium flux growth of bulk GaN. Part I: System development

NASA Astrophysics Data System (ADS)

Von Dollen, Paul; Pimputkar, Siddha; Alreesh, Mohammed Abo; Albrithen, Hamad; Suihkonen, Sami; Nakamura, Shuji; Speck, James S.

2016-12-01

Though several methods exist to produce bulk crystals of gallium nitride (GaN), none have been commercialized on a large scale. The sodium flux method, which involves precipitation of GaN from a sodium-gallium melt supersaturated with nitrogen, offers potentially lower cost production due to relatively mild process conditions while maintaining high crystal quality. We successfully developed a novel apparatus for conducting crystal growth of bulk GaN using the sodium flux method which has advantages with respect to prior reports. A key task was to prevent sodium loss or migration from the growth environment while permitting N2 to access the growing crystal. We accomplished this by implementing a reflux condensing stem along with a reusable capsule containing a hermetic seal. The reflux condensing stem also enabled direct monitoring of the melt temperature, which has not been previously reported for the sodium flux method. Furthermore, we identified and utilized molybdenum and the molybdenum alloy TZM as a material capable of directly containing the corrosive sodium-gallium melt. This allowed implementation of a crucible-free system, which may improve process control and potentially lower crystal impurity levels. Nucleation and growth of parasitic GaN ("PolyGaN") on non-seed surfaces occurred in early designs. However, the addition of carbon in later designs suppressed PolyGaN formation and allowed growth of single crystal GaN. Growth rates for the (0001) Ga face (+c-plane) were up to 14 μm/h while X-ray omega rocking (ω-XRC) curve full width half-max values were 731″ for crystals grown using a later system design. Oxygen levels were high, >1019 atoms/cm3, possibly due to reactor cleaning and handling procedures.

The effectiveness of sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) on the impurities removal of saturated salt solution

NASA Astrophysics Data System (ADS)

Pujiastuti, C.; Ngatilah, Y.; Sumada, K.; Muljani, S.

2018-01-01

Increasing the quality of salt can be done through various methods such as washing (hydro-extraction), re-crystallization, ion exchange methods and others. In the process of salt quality improvement by re-crystallization method where salt product diluted with water to form saturated solution and re-crystallized through heating process. The quality of the salt produced is influenced by the quality of the dissolved salt and the crystallization mechanism applied. In this research is proposed a concept that before the saturated salt solution is recrystallized added a chemical for removal of the impurities such as magnesium ion (Mg), calcium (Ca), potassium (K) and sulfate (SO4) is contained in a saturated salt solution. The chemical reagents that used are sodium hydroxide (NaOH) 2 N and sodium carbonate (Na2CO3) 2 N. This research aims to study effectiveness of sodium hydroxide and sodium carbonate on the impurities removal of magnesium (Mg), calcium (Ca), potassium (K) and sulfate (SO4). The results showed that the addition of sodium hydroxide solution can be decreased the impurity ions of magnesium (Mg) 95.2%, calcium ion (Ca) 45%, while the addition of sodium carbonate solution can decreased magnesium ion (Mg) 66.67% and calcium ion (Ca) 77.5%, but both types of materials are not degradable sulfate ions (SO4). The sodium hydroxide solution more effective to decrease magnesium ion than sodium carbonate solution, and the sodium carbonate solution more effective to decrease calcium ion than sodium hydroxide solution.

Universal Immunoprobe for (Per)Chlorate-Reducing Bacteria

PubMed Central

O'Connor, Susan M.; Coates, John D.

2002-01-01

Recent studies in our lab have demonstrated the ubiquity and diversity of microorganisms which couple growth to the reduction of chlorate or perchlorate [(per)chlorate] under anaerobic conditions. We identified two taxonomic groups, the Dechloromonas and the Dechlorosoma groups, which represent the dominant (per)chlorate-reducing bacteria (ClRB) in the environment. As part of these studies we demonstrated that chlorite dismutation is a central step in the reductive pathway of (per)chlorate that is common to all ClRB and which is mediated by the enzyme chlorite dismutase (CD). Initial studies on CD suggested that this enzyme is highly conserved among the ClRB, regardless of their phylogenetic affiliation. As such, this enzyme makes an ideal target for a probe specific for these organisms. Polyclonal antibodies were commercially raised against the purified CD from the ClRB Dechloromonas agitata strain CKB. The obtained antiserum was deproteinated by ammonium sulfate precipitation, and the antigen binding activity was assessed using dot blot analysis of a serial dilution of the antiserum. The titers obtained with purified CD indicated that the antiserum had a high affinity for the CD enzyme, and activity was observed in dilutions as low as 10−6 of the original antiserum. The antiserum was active against both cell lysates and whole cells of D. agitata, but only if the cells were grown anaerobically with (per)chlorate. No response was obtained with aerobically grown cultures. In addition to D. agitata, dot blot analysis employed with both whole-cell suspensions and cell lysates of several diverse ClRB representing the alpha, beta, and gamma subclasses of Proteobacteria tested positive regardless of phylogenetic affiliation. Interestingly, the dot blot response obtained for each of the ClRB cell lysates was different, suggesting that there may be some differences in the antigenic sites of the CD protein produced in these organisms. In general, no reactions were observed with cells or cell lysates of the organisms closely related to the ClRB which could not grow by (per)chlorate reduction. These studies have resulted in the development of a highly specific and sensitive immunoprobe based on the commonality of the CD enzyme in ClRB which can be used to assess dissimilatory (per)chlorate-reducing populations in environmental samples regardless of their phylogenetic affiliations. PMID:12039773

METHOD FOR REMOVING SODIUM OXIDE FROM LIQUID SODIUM

DOEpatents

Bruggeman, W.H.; Voorhees, B.G.

1957-12-01

A method is described for removing sodium oxide from a fluent stream of liquid sodium by coldtrapping the sodium oxide. Apparatus utilizing this method is disclosed in United States Patent No. 2,745,552. Sodium will remain in a molten state at temperatures below that at which sodium oxide will crystallize out and form solid deposits, therefore, the contaminated stream of sodium is cooled to a temperature at which the solubility of sodium oxide in sodium is substantially decreased. Thereafter the stream of sodium is passed through a bed of stainless steel wool maintained at a temperature below that of the stream. The stream is kept in contact with the wool until the sodium oxide is removed by crystal growth on the wool, then the stream is reheated and returned to the system. This method is useful in purifying reactor coolants where the sodium oxide would otherwise deposit out on the walls and eventually plug the coolant tubes.

Nitrates, chlorates and trihalomethanes in swimming pool water.

PubMed Central

Beech, J A; Diaz, R; Ordaz, C; Palomeque, B

1980-01-01

Water from swimming pools in the Miami area was analyzed for nitrates, chlorates and trihalomethanes. The average concentrations of nitrate and chlorate found in freshwater pools were 8.6 mg/liter and 16 mg/liter respectively, with the highest concentrations being 54.9 mg/liter and 124 mg/liter, respectively. The average concentration of total trihalomethanes found in freshwater pools was 125 micrograms/liter (mainly chloroform) and in saline pools was 657 micrograms/liter (mainly bromoform); the highest concentration was 430 micrograms/liter (freshwater) and 1287 micrograms/liter (saltwater). The possible public health significance of these results is briefly discussed. PMID:7350831

A novel stopped flow injection-amperometric procedure for the determination of chlorate.

PubMed

Tue-Ngeun, Orawan; Jakmunee, Jaroon; Grudpan, Kate

2005-12-15

A novel stopped flow injection-amperometric (sFI-Amp) procedure for determination of chlorate has been developed. The reaction of chlorate with excess potassium iodide and hydrochloric acid, forming iodine/triiodide that is further electrochemically reduced at a glassy carbon electrode at +200mV versus Ag/AgCl electrode is employed. In order to increase sensitivity without using of too high acid concentration, promoting of the reaction by increasing reaction time and temperature can be carried out. This can be done without increase of dispersion of the product zone by stopping the flow while the injected zone is being in a mixing coil which is immersed in a water bath of 55+/-0.5 degrees C. In a closed system of FIA, a side reaction of oxygen with iodide is also minimized. Under a set of conditions, linear calibration graphs were in the ranges of 1.2x10(-6)-6.0x10(-5)moll(-1)and 6.0x10(-5)-6.0x10(-4)moll(-1). A sample throughput of 25h(-1) was accomplished. Relative standard deviation was 2% (n=21, 1.2x10(-4)moll(-1) chlorate). The proposed sFI-Amp procedure was successfully applied to the determination of chlorate in soil samples from longan plantation area.

Ubiquity and Diversity of Dissimilatory (Per)chlorate-Reducing Bacteria

PubMed Central

Coates, John D.; Michaelidou, Urania; Bruce, Royce A.; O’Connor, Susan M.; Crespi, Jill N.; Achenbach, Laurie A.

1999-01-01

Environmental contamination with compounds containing oxyanions of chlorine, such as perchlorate or chlorate [(per)chlorate] or chlorine dioxide, has been a constantly growing problem over the last 100 years. Although the fact that microbes reduce these compounds has been recognized for more than 50 years, only six organisms which can obtain energy for growth by this metabolic process have been described. As part of a study to investigate the diversity and ubiquity of microorganisms involved in the microbial reduction of (per)chlorate, we enumerated the (per)chlorate-reducing bacteria (ClRB) in very diverse environments, including pristine and hydrocarbon-contaminated soils, aquatic sediments, paper mill waste sludges, and farm animal waste lagoons. In all of the environments tested, the acetate-oxidizing ClRB represented a significant population, whose size ranged from 2.31 × 103 to 2.4 × 106 cells per g of sample. In addition, we isolated 13 ClRB from these environments. All of these organisms could grow anaerobically by coupling complete oxidation of acetate to reduction of (per)chlorate. Chloride was the sole end product of this reductive metabolism. All of the isolates could also use oxygen as a sole electron acceptor, and most, but not all, could use nitrate. The alternative electron donors included simple volatile fatty acids, such as propionate, butyrate, or valerate, as well as simple organic acids, such as lactate or pyruvate. Oxidized-minus-reduced difference spectra of washed whole-cell suspensions of the isolates had absorbance maxima close to 425, 525, and 550 nm, which are characteristic of type c cytochromes. In addition, washed cell suspensions of all of the ClRB isolates could dismutate chlorite, an intermediate in the reductive metabolism of (per)chlorate, into chloride and molecular oxygen. Chlorite dismutation was a result of the activity of a single enzyme which in pure form had a specific activity of approximately 1,928 μmol of chlorite per mg of protein per min. Analyses of the 16S ribosomal DNA sequences of the organisms indicated that they all belonged to the alpha, beta, or gamma subclass of the Proteobacteria. Several were closely related to members of previously described genera that are not recognized for the ability to reduce (per)chlorate, such as the genera Pseudomonas and Azospirllum. However, many were not closely related to any previously described organism and represented new genera within the Proteobacteria. The results of this study significantly increase the limited number of microbial isolates that are known to be capable of dissimilatory (per)chlorate reduction and demonstrate the hitherto unrecognized phylogenetic diversity and ubiquity of the microorganisms that exhibit this type of metabolism. PMID:10583970

Contribution of tap water to chlorate and perchlorate intake: a market basket study.

PubMed

Asami, Mari; Yoshida, Nobue; Kosaka, Koji; Ohno, Koichi; Matsui, Yoshihiko

2013-10-01

The contributions of water to total levels of chlorate and perchlorate intake were determined using food and water samples from a market basket study from 10 locations in Japan between 2008 and 2009. Foods were categorized into 13 groups and analyzed along with tap water. The average total chlorate intake was 333 (min. 193-max. 486) μg/day for samples cooked with tap water. The contribution of tap water to total chlorate intake was as high as 47%-58%, although total chlorate intake was less than 32% of the tolerable daily intake, 1500 μg/day for body weight of 50 kg. For perchlorate, daily intake from water was 0.7 (0.1-4.4) μg/day, which is not high compared to the average total intake of 14 (2.5-84) μg/day, while the reference dose (RfD) is 35 μg/day and the provisional maximum tolerable daily intake (PMTDI) is 500 μg/day for body weight of 50 kg. The highest intake of perchlorate was 84 μg/day, where concentrations in foods were high, but not in water. The contribution of water to total perchlorate intake ranged from 0.5% to 22%, while the ratio of highest daily intake to RfD was 240% and that to PMTDI was 17%. Eight baby formulas were also tested--total chlorate and perchlorate intakes were 147 (42-332) μg/day and 1.11 (0.05-4.5) μg/day, respectively, for an ingestion volume of 1 L/day if prepared with tap water. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Purification and properties of trimethylamine oxide reductase from Salmonella typhimurium.

PubMed Central

Kwan, H S; Barrett, E L

1983-01-01

The major inducible trimethylamine oxide reductase was purified from Salmonella typhimurium LT2. The molecular weights of the native enzyme were estimated to be 332,000 by gel filtration and 170,000 by nondenaturing disc gel electrophoresis. In sodium dodecyl sulfate-gel electrophoresis, the enzyme formed a single band of molecular weight 84,000. The isoelectric point was 4.28. Maximum activity was at pH 5.65 and 45 degrees C. Reduced flavin mononucleotide, but not reduced flavin adenine dinucleotide, served as an electron donor. The Km for trimethylamine oxide was 0.89 mM and Vmax was 1,450 U/mg of protein. The enzyme reduced chlorate with a Km of 2.2 mM and a Vmax of 350 U/mg of protein. Images PMID:6350272

Influence of Surfactants on Sodium Chloride Crystallization in Confinement

PubMed Central

2017-01-01

We study the influence of different surfactants on NaCl crystallization during evaporation of aqueous salt solutions. We found that at concentrations of sodium chloride close to saturation, only the cationic surfactant CTAB and the nonionic surfactant Tween 80 remain stable. For the nonionic surfactant, the high concentration of salt does not significantly change either the critical micellar concentration (CMC) or the surface tension at the CMC; for the cationic surfactant, the CMC is reduced by roughly 2 orders of magnitude upon adding the salt. The presence of both types of surfactants in the salt solution delays the crystallization of sodium chloride with evaporation. This, in turn, leads to high supersaturation which induces the rapid precipitation of a hopper crystal in the bulk. The crystallization inhibitor role of these surfactants is shown to be mainly due to the passivation of nucleation sites at both liquid/air and solid/liquid interfaces rather than a change in the evaporation rate which is found not to be affected by the presence of the surfactants. The adsorption of surfactants at the liquid/air interface prevents the crystallization at this location which is generally the place where the precipitation of sodium chloride is observed. Moreover, sum frequency generation spectroscopy measurements show that the surfactants are also present at the solid/liquid interface. The incorporation of the surfactants into the salt crystals is investigated using a novel, but simple, method based on surface tension measurements. Our results show that the nonionic surfactant Tween 80 is incorporated in the NaCl crystals but the cationic surfactant CTAB is not. Taken together, these results therefore allow us to establish the effect of the presence of surfactants on sodium chloride crystallization. PMID:28425711

Modelling sodium cobaltate by mapping onto magnetic Ising model

NASA Astrophysics Data System (ADS)

Gemperline, Patrick; Morris, David Jonathan Pryce

Fast Ion conductors are a class of crystals that are frequently used as battery materials, especially in smart phones, laptops, and other portable devices. Sodium Cobalt Oxide, NaxCoO2, falls into this class of crystals, but is unique because it possesses the ability to act as a thermoelectric material and a superconductor at different concentrations of Na+. The crystal lattice is mapped onto an Ising Magnetic Spin model and a Monte-Carol Simulation is used to find the most energetically favorable configuration of spins. This spin configuration is mapped back to the crystal lattice resulting in the most stable crystal structure of Sodium Cobalt Oxide at various concentrations. Knowing the atomic structures of the crystals will aid in the research of the materials capabilities and the possible uses of the material commercially. Ohio Supercomputer Center. 1987. Ohio Supercomputer Center. Columbus OH: Ohio Supercomputer Center. and the John Hauck Foundation.

Sodium Flux Growth of Bulk Gallium Nitride

NASA Astrophysics Data System (ADS)

Von Dollen, Paul Martin

This dissertation focused on development of a novel apparatus and techniques for crystal growth of bulk gallium nitride (GaN) using the sodium flux method. Though several methods exist to produce bulk GaN, none have been commercialized on an industrial scale. The sodium flux method offers potentially lower cost production due to relatively mild process conditions while maintaining high crystal quality. But the current equipment and methods for sodium flux growth of bulk GaN are generally not amenable to large-scale crystal growth or in situ investigation of growth processes, which has hampered progress. A key task was to prevent sodium loss or migration from the sodium-gallium growth melt while permitting N2 gas to access the growing crystal, which was accomplished by implementing a reflux condensing stem along with a reusable sealed capsule. The reflux condensing stem also enabled direct monitoring and control of the melt temperature, which has not been previously reported for the sodium flux method. Molybdenum-based materials were identified from a corrosion study as candidates for direct containment of the corrosive sodium-gallium melt. Successful introduction of these materials allowed implementation of a crucible-free containment system, which improved process control and can potentially reduce crystal impurity levels. Using the new growth system, the (0001) Ga face (+c plane) growth rate was >50 mum/hr, which is the highest bulk GaN growth rate reported for the sodium flux method. Omega X-ray rocking curve (?-XRC) measurements indicated the presence of multiple grains, though full width at half maximum (FWHM) values for individual peaks were <100 arcseconds. Oxygen impurity concentrations as measured by secondary ion mass spectroscopy (SIMS) were >1020 atoms/cm3, possibly due to reactor cleaning and handling procedures. This dissertation also introduced an in situ technique to correlate changes in N2 pressure with dissolution of nitrogen and precipitation of GaN from the sodium-gallium melt. Different stages of N2 pressure decay were identified and linked to distinct modes of GaN crystal growth. Based on this analysis, the highest growth rate may have up to 90 mum/hr, and did not appear to be mass-transport limited, in contrast to previous reports. Several refinements and improvements of the novel equipment and methods introduced were also explored, all of which have potential to further advance state of the art sodium flux growth of bulk GaN.

GROWTH AND CHARACTERIZATION OF SINGLE CRYSTALS OF RARE EARTH COMPOUNDS.

DTIC Science & Technology

SINGLE CRYSTALS, CRYSTAL GROWTH), (*CRYSTAL GROWTH, SINGLE CRYSTALS), (*RARE EARTH COMPOUNDS, SINGLE CRYSTALS), EPITAXIAL GROWTH, SODIUM COMPOUNDS, CHLORIDES, VAPOR PLATING, ELECTROSTATIC FIELDS, ENERGY, ATOMIC PROPERTIES , BONDING

The Investigation of Chlorate/Iron-Phase Mixtures as a Possible Source of Oxygen and Chlorine Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Clark, J.; Sutter, B.; Morris, R. V.; Archer, P. D.; Ming, D. W.; Niles, P.; Mahaffy, P.; Navarro-Gonzalez, R.

2016-01-01

The Sample Analysis at Mars (SAM) instrument on board the Curiosity Rover has detected oxygen and HCl gas releases from all analyzed Gale Crater sediments. The presence of perchlorate ClO4(sup-) and/or chlorates ClO3(sup-) are potential sources of the aforementioned O2 releases. The detections of O2 and HCl gas releases and chlorinated hydrocarbons by SAM coupled with the detection of perchlorates by Phoenix Lander's 2008 Wet Chemistry Laboratory all suggest that perchlorates, and possibly chorates, may be present in the Gale Crater sediments. Previous laboratory studies have attempted to replicate these O2 releases by heating perchlorates and chlorates in instruments operated similarly to those in the SAM instrument. Early studies found that pure perchlorates release O2 at temperatures higher than those observed in SAM data. Subsequently, studies were done to test the effects of mixing iron-phase minerals, analogous to those detected on Mars by ChemMin, with perchlorates. The iron in these minerals acts as a catalyst and causes O2 to be released from the perchlorate at a lower temperature. These studies found that perchlorate solutions mixed with either Hawaii palagonite or ferrihydrite produce O2 releases at temperatures similar to the Rocknest (RN) windblown deposit and the John Klein (JK) drill sample from the Sheepbed mudstone. The study also determined that perchlorate mixtures with magnetite, hematite, fayalite-magnetite, ilmentite, and pyrrhotite produce O2 releases at temperatures similar to the Confidence Hills (CH) drill sample from the Murray mudstone. Oxygen re-leases from pure chlorates were recently compared with the SAM data. Laboratory analyses determined that Ca-chlorate produces O2 and HCl peaks that are similar to those detected in RN and JK materials. Currently, no perchlorate/chlorate mixture with iron-phase minerals can explain the O2 releases from either the Cumberland (CB) drill sample from the Sheepbed mudstone or Windjana (WJ) drill sample from the Kimberly sandstone. Mixtures of chlorate solutions with iron-phase minerals may produce O2 peaks at temperatures that match those from CB and WJ materials. The goal of this work is to determine if heating chlorate solutions mixed with iron-phase minerals will produce O2 and HCl peak temperatures similar to O2 and HCl peak temperatures of sediments analyzed by SAM, particularly the WJ and CB materials.

[Exposure to organic halogen compounds in drinking water of 9 Italian regions: exposure to chlorites, chlorates, thrihalomethanes, trichloroethylene and tetrachloroethylene].

PubMed

Fantuzzi, G; Aggazzotti, G; Righi, E; Predieri, G; Giacobazzi, P; Kanitz, S; Barbone, F; Sansebastiano, G; Ricci, C; Leoni, V; Fabiani, L; Triassi, M

2007-01-01

This study investigated the exposure to organohalogens compounds in drinking water from 9 Italian towns (Udine, Genova, Parma, Modena, Siena, Roma, L'Aquila, Napoli and Catania). Overall, 1199 samples collected from 72 waterworks were analyzed. THMs, trichloroethylene and tetrachloroethylene were evaluated using the head-space gas chromatographic technique (detection limit of 0.01 microg/l; chlorite and chlorate analysis was performed by ion chromatography (detection limit of 20 microg/l). THMs were evidenced in 925 samples (77%) (median value: 1.12 micro/l; range: 0.01-54 mciro/l) and 7 were higher than the THMs Italian limit of 30 microg/l. Chlorite and chlorate levels were higher than the detection limit in 45% for chlorite and in 34% for chlorate samples; median values were 221 microg/l and 76 microg/l, respectively. Chlorite values were higher than the chlorite Italian limit (700 microg/l) in 35 samples (8.7%). Trichloroethylene and tetrachloroethylene were measured in 29% and 44% of the investigated samples and showed values lower than the Italian limit (highest levels of 6 microg/l and 9 microg/l, respectively). The low levels detected of THMs, trichloroethylene and tetrachloroethylene have no potentials effects on human health, whereas, the levels of chlorite and chlorates should be further evaluated and their potential effects for the populations using these drinking waters, better understood.

Monitoring of antisolvent crystallization of sodium scutellarein by combined FBRM-PVM-NIR.

PubMed

Liu, Xuesong; Sun, Di; Wang, Feng; Wu, Yongjiang; Chen, Yong; Wang, Longhu

2011-06-01

Antisolvent crystallization can be used as an alternative to cooling or evaporation for the separation and purification of solid product in the pharmaceutical industry. To improve the process understanding of antisolvent crystallization, the use of in-line tools is vital. In this study, the process analytical technology (PAT) tools including focused beam reflectance measurement (FBRM), particle video microscope (PVM), and near-infrared spectroscopy (NIRS) were utilized to monitor antisolvent crystallization of sodium scutellarein. FBRM was used to monitor chord count and chord length distribution of sodium scutellarein particles in the crystallizer, and PVM, as an in-line video camera, provided pictures imaging particle shape and dimension. In addition, a quantitative model of PLS was established by in-line NIRS to detect the concentration of sodium scutellarein in the solvent and good calibration statistics were obtained (r(2) = 0.976) with the residual predictive deviation value of 11.3. The discussion over sensitivities, strengths, and weaknesses of the PAT tools may be helpful in selection of suitable PAT techniques. These in-line techniques eliminate the need for sample preparation and offer a time-saving approach to understand and monitor antisolvent crystallization process. Copyright © 2011 Wiley-Liss, Inc.

Chalk in the prime.

PubMed Central

Yeo, H; Doyle, T; Saynor, R; Smith, G H

1986-01-01

After observations of cloudiness in the perfusion circuit at open intracardiac operations, laboratory experiments showed a precipitate in a Hartmann's solution (compound sodium lactate solution, Ringer-lactate) and sodium bicarbonate based priming fluid used for cardiopulmonary bypass. The precipitate was found to consist of calcium carbonate crystals. The crystals were not dissolved by adding plasma proteins, nor were they sufficiently cleared from the extracorporeal circuit by a 40 microns filter in the arterial line. The crystals may embolise in microvascular beds and thus be a cause of postoperative morbidity. The practice of adding sodium bicarbonate to the pump prime may be unnecessary. Images PMID:3010485

Influence of convection on free growth of dendrite crystals from solution

NASA Technical Reports Server (NTRS)

Hallett, J.; Wedum, E.

1979-01-01

The free growth of dendrites in a uniformly supercooled solution was examined using cine photography with a Schlieren optical system. Crystals were grown in the bulk of the solution from a centrally located capillary tube, nucleated at the interface with a liquid nitrogen cooled wire. Crystals propagated along the tube, the slower growing orientations eliminated, and emerged at the tip, usually growing parallel to the tube direction. For both sodium sulfate decahydrate from its solution and ice from sodium chloride solution, growth rate and fineness of dendrites increased with supercooling. In sodium sulfate, upward convection of the less dense depleted solution occurs; downward convection was observed for the rejected, more concentrated sodium chloride solution. In both cases, there was a spatial and temporal delay in the release of the convective plume from the moving dendrite tip. The role of this convection on the growth characteristics and the production of secondary crystals is examined. A proposed low-g experiment to examine differences in growth rate, crystal texture, and secondary nucleation in a reduced convective regime where molecular diffusion is the dominant transfer process is discussed.

Molybdenum cofactor (chlorate-resistant) mutants of Klebsiella pneumoniae M5al can use hypoxanthine as the sole nitrogen source.

PubMed Central

Garzón, A; Li, J; Flores, A; Casadesus, J; Stewart, V

1992-01-01

Selection for chlorate resistance yields mol (formerly chl) mutants with defects in molybdenum cofactor synthesis. Complementation and genetic mapping analyses indicated that the Klebsiella pneumoniae mol genes are functionally homologous to those of Escherichia coli and occupy analogous genetic map positions. Hypoxanthine utilization in other organisms requires molybdenum cofactor as a component of xanthine dehydrogenase, and thus most chlorate-resistant mutants cannot use hypoxanthine as a sole source of nitrogen. Surprisingly, the K. pneumoniae mol mutants and the mol+ parent grew equally well with hypoxanthine as the sole nitrogen source, suggesting that K. pneumoniae has a molybdenum cofactor-independent pathway for hypoxanthine utilization. PMID:1400180

Combating Terrorism: State Should Enhance Its Performance Measures for Assessing Efforts in Pakistan to Counter Improvised Explosive Devices

DTIC Science & Technology

2012-05-01

readily switch to another precursor chemical to make IEDs. According to DOD, other products available in Pakistan such as potassium chlorate , used in...chemicals. According to State officials, other substitutes for CAN, including urea and potassium chlorate , are exported by countries other than Pakistan

Counterterrorism: U.S. Agencies Face Challenges Countering the Use of Improvised Explosive Devices in the Afghanistan/Pakistan Region

DTIC Science & Technology

2012-07-12

make IEDs. According to DOD, other products available in Pakistan—such as potassium chlorate , used in making matches, and urea, another commonly used...IED precursor chemicals. According to State officials, other substitutes for CAN, including potassium chlorate and urea, are exported by countries

Cranial MR imaging findings of potassium chlorate intoxication.

PubMed

Mutlu, Hakan; Silit, Emir; Pekkafali, Zekai; Basekim, C Cinar; Kizilkaya, Esref; Ay, Hakan; Karsli, A Fevzi

2003-08-01

We present the case of a patient who attempted suicide by ingesting matchstick heads (55% potassium chlorate). The patient presented to the emergency room with loss of consciousness, and MR imaging revealed symmetric hyperintense signal within the deep gray matter and medial temporal lobes. The patient improved after undergoing conventional treatment and hyperbaric oxygen.

Characterization of Inclusions in Evolution of Sodium Sulfate Using Terahertz Time-domain Spectroscopy.

PubMed

Bao, Rima; Wu, Zhikui; Li, Hao; Wang, Fang; Miao, Xinyang; Feng, Chengjing

2017-01-01

The study of fluid inclusion is one of the important means to understanding the evolution of mineral crystals, and can therefore provide original information of mineral evolution. In the process of evolution, outside factors such as temperature and pressure, directly affect the number and size of inclusions, and thus are related to the properties of crystals. In this paper, terahertz time-domain spectroscopy (THz-TDS) was used to detect sodium sulfate crystals with different growth temperatures, and absorption coefficient spectra of the samples were obtained. It is suggested that the evolution of sodium sulfate could be divided into two stages, and 80°C was the turning point. X-ray diffraction (XRD) and polarizing microscopy were used to support this conclusion. The research showed that THz-TDS could characterize the evolution of mineral crystals, and it had a unique advantage in terms of crystal evolution.

Influence of mixing and ultrasound frequency on antisolvent crystallisation of sodium chloride.

PubMed

Lee, Judy; Ashokkumar, Muthupandian; Kentish, Sandra E

2014-01-01

Ultrasound is known to promote nucleation of crystals and produce a narrower size distribution in a controlled and reproducible manner for the crystallisation process. Although there are various theories that suggest cavitation bubbles are responsible for sonocrystallisation, most studies use power ultrasonic horns that generate both intense shear and cavitation and this can mask the role that cavitation bubbles play. High frequency ultrasound from a plate transducer can be used to examine the effect of cavitation bubbles without the intense shear effect. This study reports the crystal size and morphology with various mixing speeds and ultrasound frequencies. The results show high frequency ultrasound produced sodium chloride crystals of similar size distribution as an ultrasonic horn. In addition, ultrasound generated sodium chloride crystals having a more symmetrical cubic structure compared to crystals produced by a high shear mixer. Copyright © 2013 Elsevier B.V. All rights reserved.

Stress-induced rearrangement of Fusarium retrotransposon sequences.

PubMed

Anaya, N; Roncero, M I

1996-11-27

Rearrangement of fusarium oxysporum retrotransposon skippy was induced by growth in the presence of potassium chlorate. Three fungal strains, one sensitive to chlorate (Co60) and two resistant to chlorate and deficient for nitrate reductase (Co65 and Co94), were studied by Southern analysis of their genomic DNA. Polymorphism was detected in their hybridization banding pattern, relative to the wild type grown in the absence of chlorate, using various enzymes with or without restriction sites within the retrotransposon. Results were consistent with the assumption that three different events had occurred in strain Co60: genomic amplification of skippy yielding tandem arrays of the element, generation of new skippy sequences, and deletion of skippy sequences. Amplification of Co60 genomic DNA using the polymerase chain reaction and divergent primers derived from the retrotransposon generated a new band, corresponding to one long terminal repeat plus flanking sequences, that was not present in the wild-type strain. Molecular analysis of nitrate reductase-deficient mutants showed that generation and deletion of skippy sequences, but not genomic amplification in tandem repeats, had occurred in their genomes.

The potential role of salt abuse on the risk for kidney stone formation

NASA Technical Reports Server (NTRS)

Sakhaee, K.; Harvey, J. A.; Padalino, P. K.; Whitson, P.; Pak, C. Y.

1993-01-01

The kidney stone-forming risk of a high sodium diet was evaluated by assessing the effect of such a diet on the crystallization of stone-forming salts in urine. Fourteen normal subjects participated in 2 phases of study of 10 days duration each, comprising a low sodium phase (basal metabolic diet containing 50 mmol. sodium per day) and a high sodium phase (basal diet plus 250 mmol. sodium chloride per day). The high sodium intake significantly increased urinary sodium (34 +/- 12 to 267 +/- 56 mmol. per day), calcium (2.73 +/- 1.03 to 3.93 +/- 1.51 mmol. per day) and pH (5.79 +/- 0.44 to 6.15 +/- 0.25), and significantly decreased urinary citrate (3.14 +/- 1.19 to 2.52 +/- 0.83 mmol. per day). Arterialized venous blood bicarbonate and total serum carbon dioxide concentrations decreased significantly during the high sodium diet, whereas serum chloride concentration increased. However, no change in arterialized venous pH was detected. Thus, a high sodium intake not only increased calcium excretion, but also increased urinary pH and decreased citrate excretion. The latter effects are probably due to sodium-induced bicarbonaturia and a significant decrease in serum bicarbonate concentration, respectively. Commensurate with these changes, the urinary saturation of calcium phosphate (brushite) and monosodium urate increased, and the inhibitor activity against calcium oxalate crystallization (formation product) decreased. The net effect of a high sodium diet was an increased propensity for the crystallization of calcium salts in urine.

Sodium doping in ZnO crystals

NASA Astrophysics Data System (ADS)

Parmar, N. S.; Lynn, K. G.

2015-01-01

ZnO bulk single crystals were doped with sodium by thermal diffusion. Positron annihilations spectroscopy confirms the filling of zinc vacancies, to >6 μm deep in the bulk. Secondary-ion mass spectrometry measurement shows the diffusion of sodium up to 8 μm with concentration (1-3.5) × 1017 cm-3. Broad photoluminescence excitation peak at 3.1 eV, with onset appearance at 3.15 eV in Na:ZnO, is attributed to an electronic transition from a NaZn level at ˜(220-270) meV to the conduction band. Resistivity in Na doped ZnO crystals increases up to (4-5) orders of magnitude at room temperature.

Diffusion of water and sodium counter-ions in nanopores of a β-lactoglobulin crystal: a molecular dynamics study

NASA Astrophysics Data System (ADS)

Malek, Kourosh; Odijk, Theo; Coppens, Marc-Olivier

2005-07-01

The dynamics of water and sodium counter-ions (Na+) in a C2221 orthorhombic β-lactoglobulin crystal is investigated by means of 5 ns molecular dynamics simulations. The effect of the fluctuation of the protein atoms on the motion of water and sodium ions is studied by comparing simulations in a rigid and in a flexible lattice. The electrostatic interactions of sodium ions with the positively charged LYS residues inside the crystal channels significantly influence the ionic motion. According to our results, water molecules close to the protein surface undergo an anomalous diffusive motion. On the other hand, the motion of water molecules further away from the protein surface is normal diffusive. Protein fluctuations affect the diffusion constant of water, which increases from 0.646 ± 0.108 to 0.887 ± 0.41 nm2 ns-1, when protein fluctuations are taken into account. The pore size (0.63-1.05 nm) and the water diffusivities are in good agreement with previous experimental results. The dynamics of sodium ions is disordered. LYS residues inside the pore are the main obstacles to the motion of sodium ions. However, the simulation time is still too short for providing a precise description of anomalous diffusion of sodium ions. The results are not only of interest for studying ion and water transport through biological nanopores, but may also elucidate water-protein and ion-protein interactions in protein crystals.

Structure characterization, photoluminescence and dielectric properties of a new hybrid compound containing chlorate anions of zincate (II)

NASA Astrophysics Data System (ADS)

Lassoued, Mohamed Saber; Abdelbaky, Mohammed S. M.; Ben Soltan, Wissem; Lassoued, Abdelmajid; Ammar, Salah; Gadri, Abdellatif; Ben Salah, Abdelhamid; García-Granda, Santiago

2018-04-01

A new hybrid compound, bis (2-aminophenylenamonium) tetrachlorozincate (II), was synthesized and formulated as (C6H9N2)2ZnCl4. Its crystal structure was solved by single crystal X-ray diffraction reveling that compound crystallizes in the monoclinic system, space group C2/c (N°: 15) with cell parameters a = 7.4957(4) Å, b = 25.6837(15) Å, c = 9.4041(5) Å, β = 94.35(0)°, V = 1805.23(45) Å3. Their atomic arrangement can be described as an alternation of inorganic and organic layers, [ZnCl4]2- tetrahedral anions and 2-aminophenylenamonium cations. The cohesion of the atomic arrangement is ensured by hydrogen bonds (strong Nsbnd H⋯N and weak Nsbnd H⋯Cl) and π-π stacking interactions between identical antiparallel organic moieties. In optical transmission and photoluminescence measurements, this material exhibit two absorption bands (253 and 316 nm) and a strong emission line (390 nm), while the thermal analysis disclosed a phase transition at 420-445 K previously to the sample decomposition at 476 K. Finally, electrical measurements were performed to discuss the phase-transition mechanism.

Mechanisms for Improved Hygroscopicity of L-Arginine Valproate Revealed by X-Ray Single Crystal Structure Analysis.

PubMed

Ito, Masataka; Nambu, Kaori; Sakon, Aya; Uekusa, Hidehiro; Yonemochi, Etsuo; Noguchi, Shuji; Terada, Katsuhide

2017-03-01

Valproic acid is widely used as an antiepileptic agent. Valproic acid is in liquid phase while sodium valproate is in solid phase at room temperature. Sodium valproate is hard to manufacture because of its hygroscopic and deliquescent properties. To improve these, cocrystal and salt screening for valproic acid was employed in this study. Two solid salt forms, l-arginine valproate and l-lysine valproate, were obtained and characterized. By using dynamic vapor sorption method, the critical relative humidity of sodium valproate, l-arginine valproate, and l-lysine valproate were measured. Critical relative humidity of sodium valproate was 40%, of l-lysine valproate was 60%, and of l-arginine valproate was 70%. Single-crystal X-ray structure determination of l-arginine valproate was employed. l-Lysine valproate was of low diffraction quality, and l-arginine valproate formed a 1:1 salt. Crystal l-arginine valproate has a disorder in the methylene carbon chain that creates 2 conformations. The carboxylate group of valproic acid is connected to the amino group of l-arginine. Crystalline morphologies were calculated from its crystal structure. Adsorption of water molecules to crystal facets was simulated by Material Studio. When comparing adsorption energy per site of these salts, sodium valproate is more capable of adsorption of water molecule than l-arginine valproate. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Synthesis, crystal structure, vibrational spectroscopy and photoluminescence of new hybrid compound containing chlorate anions of stanate (II)

NASA Astrophysics Data System (ADS)

Lassoued, Mohamed Saber; Abdelbaky, Mohammed S. M.; Lassoued, Abdelmajid; Meroño, Rafael Mendoza; Gadri, Abdellatif; Ammar, Salah; Ben Salah, Abdelhamid; García-Granda, Santiago

2017-08-01

The present work aimed at studying a new organic-inorganic bis (4-amino quinolinium) hexachloro stanate (II) dihydrate compound. It was prepared and characterized by single crystal X-ray diffraction, X-ray powder, Hirshfeld surface, Spectroscopy measurement, thermal study and photoluminescence properties. It was found to crystallize in the monoclinic system (P21/c space group) with the following lattice parameters: a = 7.2558(6) Å, b = 13.4876(5) Å, c = 17.2107(13) Å, β = 102.028 (12)°. Its crystal structure was determined and refined down to an R value of 0.06 and a wR value of 0.087. The structure consisted of two different alternating organic-inorganic layers. The crystal packing was stabilized by Nsbnd H⋯Cl and Osbnd H⋯Cl hydrogen bonds and π-π interactions. Hirshfeld surface analysis was used to investigate intermolecular interactions, as well 2D finger plots were conducted to reveal the contribution of these interactions in the crystal structure quantitatively. The X-ray powder is in agreement with the X-ray structure. Scanning electronic microscopy (SEM) was carried out. Furthermore, the room temperature Infra Red (IR) spectrum of the title compound was analyzed on the basis of data found in the literature. Solid state 13C NMR spectrum shows ten signals, confirming the solid state structure determined by X-ray diffraction. Thermal analysis shows two anomalies at 380 and 610 °C. The optical properties of the crystal were studied using optical absorption UV-visible and photoluminescence (PL) spectroscopy, which were investigated at room temperature.

Influence of Temperature and Catalyst on the Decomposition of Potassium Chlorate in a Simple DTA-Apparatus.

ERIC Educational Resources Information Center

Wiederholt, Erwin

1983-01-01

DTA is a technique in which the temperature difference between sample/reference is measured as a function of temperature, while both are subject to a controlled temperature program. Use of a simple DTA-apparatus in demonstrating catalytic effects of manganese dioxide and aluminum oxide on decomposition temperature of potassium chlorate is…

Chloroxyanion residue on seeds and sprouts after chlorine dioxide sanitation of alfalfa seed

USDA-ARS?s Scientific Manuscript database

The effects of a 6-h chlorine dioxide sanitation of alfalfa seed (0, 50, 100, and 200 mg/kg seed) on total coliform bacteria, seed germination, and on the presence of chlorate and perchlorate residues in seed rinse, seed soak, and in alfalfa sprouts was determined. Chlorate residues in 20000 ppm cal...

Growth, optical, ICP and thermal studies of nonlinear optical single crystal: Sodium acid phthalate (NaAP)

NASA Astrophysics Data System (ADS)

Mahadevan, M.; Arivanandhan, M.; Elangovan, K.; Anandan, P.; Ramachandran, K.

2017-07-01

Good quality single crystals of sodium acid phthalate (NaAP) were grown by slow evaporation technique. Single crystal X-ray diffraction study of the grown crystal reveals that the crystal belongs to orthorhombic system with space group B2ab. Fourier transform infrared spectrum confirms the presence of the functional groups of the grown material. Inductively coupled plasma emission spectroscopy analysis is used to confirm the presence of Na element in the sample. Thermal analysis of the NaAP crystal shows that the crystal is stable up to 140°C. Optical transmittance of the grown crystal was recorded in the wavelength range from 200 and 800 nm using UV-Vis-NIR spectrophotometer. The second harmonic generation of NaAP was analysed using Kurtz powder technique.

Close-up view of Sodium Chloride crystals in a water bubble on Expedition Six.

NASA Image and Video Library

2003-03-14

ISS006-E-39236 (14 March 2003) --- A view of sodium chloride crystals in a water bubble within a 50-millimeter metal loop was photographed by an Expedition Six crewmember. The experiment took place in the Destiny laboratory on the International Space Station (ISS).

Differential chlorate inhibition of Chaetomium globosum germination, hyphal growth, and perithecia synthesis.

PubMed

Biles, Charles L; Wright, Desiree; Fuego, Marianni; Guinn, Angela; Cluck, Terry; Young, Jennifer; Martin, Markie; Biles, Josiah; Poudyal, Shubhra

2012-12-01

Chaetomium globosum Kunze:Fr is a dermatophytic, dematiaceous fungus that is ubiquitous in soils, grows readily on cellulolytic materials, and is commonly found on water-damaged building materials. Chlorate affects nitrogen metabolism in fungi and is used to study compatibility among anamorphic fungi by inducing nit mutants. The effect of chlorate toxicity on C. globosum was investigated by amending a modified malt extract agar (MEA), oat agar, and carboxymethyl cellulose agar (CMC) with various levels of potassium chlorate (KClO(3)). C. globosum perithecia production was almost completely inhibited (90-100 %) at low levels of KClO(3) (0.1 mM) in amended MEA. Inhibition of perithecia production was also observed on oat agar and CMC at 1 and 10 mM, respectively. However, hyphal growth in MEA was only inhibited 20 % by 0.1-100 mM KClO(3) concentrations. Hyphal growth was never completely inhibited at the highest levels tested (200 mM). Higher levels of KClO(3) were needed on gypsum board to inhibit perithecia synthesis. In additional experiments, KClO(3) did not inhibit C. globosum, Fusarium oxysporum, Aspergillus niger, Penicillum expansum, and airborne fungal spore germination. The various fungal spores were not inhibited by KClO(3) at 1-100 mM levels. These results suggest that C. globosum perithecia synthesis is more sensitive to chlorate toxicity than are hyphal growth and spore germination. This research provides basic information that furthers our understanding about perithecia formation and may help in developing control methods for fungal growth on building materials.

Structure and water exchange dynamics of hydrated oxo halo ions in aqueous solution using QMCF MD simulation, large angle X-ray scattering and EXAFS.

PubMed

Eklund, Lars; Hofer, Tomas S; Persson, Ingmar

2015-01-28

Theoretical ab initio quantum mechanical charge field molecular dynamics (QMCF MD) has been applied in conjunction with experimental large angle X-ray scattering (LAXS) and EXAFS measurements to study structure and dynamics of the hydrated oxo chloro anions chlorite, ClO2(-), chlorate, ClO3(-), and perchlorate, ClO4(-). In addition, the structures of the hydrated hypochlorite, ClO(-), bromate, BrO3(-), iodate, IO3(-) and metaperiodate, IO4(-), ions have been determined in aqueous solution by means of LAXS. The structures of the bromate, metaperiodate, and orthoperiodate, H2IO6(3-), ions have been determined by EXAFS as solid sodium salts and in aqueous solution as well. The results show clearly that the only form of periodate present in aqueous solution is metaperiodate. The Cl-O bond distances in the hydrated oxo chloro anions as determined by LAXS and obtained in the QMCF MD simulations are in excellent agreement, being 0.01-0.02 Å longer than in solid anhydrous salts due to hydration through hydrogen bonding to water molecules. The oxo halo anions, all with unit negative charge, have low charge density making them typical structure breakers, thus the hydrogen bonds formed to the hydrating water molecules are weaker and more short-lived than those between water molecules in pure water. The water exchange mechanism of the oxo chloro anions resembles those of the oxo sulfur anions with a direct exchange at the oxygen atoms for perchlorate and sulfate. The water exchange rate for the perchlorate ion is significantly faster, τ0.5 = 1.4 ps, compared to the hydrated sulfate ion and pure water, τ0.5 = 2.6 and 1.7 ps, respectively. The angular radial distribution functions show that the chlorate and sulfite ions have a more complex water exchange mechanism. As the chlorite and chlorate ions are more weakly hydrated than the sulfite ion the spatial occupancy is less well-defined and it is not possible to follow any well-defined migration pattern as it is difficult to distinguish between hydrating water molecules and bulk water in the region close to the ions.

Structure and water exchange dynamics of hydrated oxo halo ions in aqueous solution using QMCF MD simulation, large angle X-ray scattering and EXAFS

PubMed Central

Eklund, Lars; Hofer, Tomas S.

2014-01-01

Theoretical ab initio quantum mechanical charge field molecular dynamics (QMCF MD) has been applied in conjunction with experimental large angle X-ray scattering (LAXS) and EXAFS measurements to study structure and dynamics of the hydrated oxo chloro anions chlorite, ClO2−, chlorate, ClO3−, and perchlorate, ClO4−. In addition, the structures of the hydrated hypochlorite, ClO−, bromate, BrO3−, iodate, IO3− and metaperiodate, IO4−, ions have been determined in aqueous solution by means of LAXS. The structures of the bromate, metaperiodate, and orthoperiodate, H2IO63−, ions have been determined by EXAFS as solid sodium salts and in aqueous solution as well. The results show clearly that the only form of periodate present in aqueous solution is metaperiodate. The Cl-O bond distances in the hydrated oxo chloro anions as determined by LAXS and obtained in the QMCF MD simulations are in excellent agreement, being 0.01–0.02 Å longer than in solid anhydrous salts due to hydration through hydrogen bonding to water molecules. The oxo halo anions, all with unit negative charge, have low charge density making them typical structure breakers, thus the hydrogen bonds formed to the hydrating water molecules are weaker and more short-lived than those between water molecules in pure water. The water exchange mechanism of the oxo chloro anions resembles those of the oxo sulfur anions with a direct exchange at the oxygen atoms for perchlorate and sulfate. The water exchange rate for the perchlorate ion is significantly faster, τ0.5=1.4 ps, compared to the hydrated sulfate ion and pure water, τ0.5=2.6 and 1.7 ps, respectively. The angular radial distribution functions show that the chlorate and sulfite ions have a more complex water exchange mechanism. As the chlorite and chlorate ions are more weakly hydrated than the sulfite ion the spatial occupancy is less well-defined and it is not possible to follow any well-defined migration pattern as it is difficult to distinguish between hydrating water molecules and bulk water in the region close to the ions. PMID:25473816

Structure and water exchange dynamics of hydrated oxo halo ions in aqueous solution using QMCF MD simulation, large angle X-ray scattering and EXAFS

DOE PAGES

Eklund, Lars; Hofer, Tomas S.; Persson, Ingmar

2014-11-26

Theoretical ab initio quantum mechanical charge field molecular dynamics (QMCF MD) has been applied in conjunction with experimental large angle X-ray scattering (LAXS) and EXAFS measurements to study structure and dynamics of the hydrated oxo chloro anions chlorite, ClO 2 –, chlorate, ClO 3 –, and perchlorate, ClO 4 –. In addition, the structures of the hydrated hypochlorite, ClO –, bromate, BrO 3 –, iodate, IO 3 – and metaperiodate, IO 4 –, ions have been determined in aqueous solution by means of LAXS. The structures of the bromate, metaperiodate, and orthoperiodate, H 2IO 6 3–, ions have been determinedmore » by EXAFS as solid sodium salts and in aqueous solution as well. The results show clearly that the only form of periodate present in aqueous solution is metaperiodate. The Cl–O bond distances in the hydrated oxo chloro anions as determined by LAXS and obtained in the QMCF MD simulations are in excellent agreement, being 0.01–0.02 Å longer than in solid anhydrous salts due to hydration through hydrogen bonding to water molecules. The oxo halo anions, all with unit negative charge, have low charge density making them typical structure breakers, thus the hydrogen bonds formed to the hydrating water molecules are weaker and more short-lived than those between water molecules in pure water. The water exchange mechanism of the oxo chloro anions resembles those of the oxo sulfur anions with a direct exchange at the oxygen atoms for perchlorate and sulfate. Here, the water exchange rate for the perchlorate ion is significantly faster, τ 0.5 = 1.4 ps, compared to the hydrated sulfate ion and pure water, τ 0.5 = 2.6 and 1.7 ps, respectively. The angular radial distribution functions show that the chlorate and sulfite ions have a more complex water exchange mechanism. As the chlorite and chlorate ions are more weakly hydrated than the sulfite ion the spatial occupancy is less well-defined and it is not possible to follow any well-defined migration pattern as it is difficult to distinguish between hydrating water molecules and bulk water in the region close to the ions.« less

Apparatus for obtaining silicon from fluosilicic acid

DOEpatents

Sanjurjo, Angel

1986-05-20

Apparatus for producing low cost, high purity solar grade silicon ingots in single crystal or quasi single crystal ingot form in a substantially continuous operation in a two stage reactor starting with sodium fluosilicate and a metal more electropositive than silicon (preferably sodium) in separate compartments having easy vapor transport therebetween and thermally decomposing the sodium fluosilicate to cause formation of substantially pure silicon and a metal fluoride which may be continuously separated in the melt and silicon may be directly and continuously cast from the melt.

Mineral resource of the month: cultured quartz crystal

USGS Publications Warehouse

,

2008-01-01

The article presents information on cultured quartz crystals, a mineral used in mobile phones, computers, clocks and other devices controlled by digital circuits. Cultured quartz, which is synthetically produced in large pressurized vessels known as autoclaves, is useful in electronic circuits for precise filtration, frequency control and timing for consumer and military use. Several ingredients are used in producing cultured quartz, including seed crystals, lascas, a solution of sodium hydroxide or sodium carbonate, lithium salts and deionized water.

Close-up view of Sodium Chloride crystals in a water bubble on Expedition Six.

NASA Image and Video Library

2003-03-13

ISS006-E-39211 (13 March 2003) --- A close up view of sodium chloride crystals in a water bubble within a 50-millimeter metal loop was photographed by an Expedition Six crewmember. The experiment took place in the Destiny laboratory on the International Space Station (ISS).

Close-up view of Sodium Chloride crystals in a water bubble on Expedition Six.

NASA Image and Video Library

2003-03-14

ISS006-E-39238 (14 March 2003) --- A close up view of sodium chloride crystals in a water bubble within a 50-millimeter metal loop was photographed by an Expedition Six crewmember. The experiment took place in the Destiny laboratory on the International Space Station (ISS).

Effect of L-Valine on the growth and characterization of Sodium Acid Phthalate (SAP) single crystals.

PubMed

Nirmala, L Ruby; Thomas Joseph Prakash, J

2013-06-01

Undoped and amino acid doped good quality single crystals of Sodium Acid Phthalate crystals (SAP) were grown by slow evaporation solution growth technique which are semiorganic in nature. The effect of amino acid (L-Valine) dopant on the growth and the properties of SAP single crystal was investigated. The single crystal X-ray diffraction studies and FT-IR studies were carried out to identify the crystal structure and the presence of functional groups in undoped and L-Valine doped SAP crystals. The transparent nature of the grown crystal was observed using UV-Visible spectrum. The thermal decomposition of the doped SAP crystals was investigated by thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). The enhancement in the NLO property of the undoped and L-Valine doped SAP crystals using KDP crystal as a reference was studied using SHG measurements. Vickers micro hardness measurements are used for the study of mechanical strength of the grown crystals. Copyright © 2013 Elsevier B.V. All rights reserved.

Solid state neutron detector and method for use

DOEpatents

Doty, F. Patrick; Zwieback, Ilya; Ruderman, Warren

2002-01-01

Crystals of lithium tetraborate or alpha-barium borate had been found to be neutron detecting materials. The crystals are prepared using known crystal growing techniques, wherein the process does not include the common practice of using a fluxing agent, such as sodium oxide or sodium fluoride, to reduce the melting temperature of the crystalline compound. Crystals prepared by this method can be sliced into thin single or polycrystalline wafers, or ground to a powder and prepared as a sintered compact or a print paste, and then configured with appropriate electronic hardware, in order to function as neutron detectors.

EFFECTS OF LASER RADIATION ON MATTER. LASER PLASMA: Thermally induced optical damage to barium-sodium niobate crystals

NASA Astrophysics Data System (ADS)

Baryshev, S. A.; Goncharova, I. F.; Konvisar, P. G.; Kuznetsov, V. A.

1990-06-01

Thermally induced optical damage (TIOD) was observed in undoped barium-sodium niobate (BSN) crystals as a result of changes in their temperature. This damage was deduced from the behavior of YAG:Nd3+ laser radiation when a BSN crystal was inserted in the resonator and also using a helium-neon laser probe beam. The experimental results were satisfactorily explained by the familiar pyroelectric model of TIOD and, in the crystals studied, an inhomogeneity of the conductivity rather than an inhomogeneity of the pyroelectric constant played the main role.

Determination of trace level bromate and perchlorate in drinking water by ion chromatography with an evaporative preconcentration technique.

PubMed

Liu, Yongjian; Mou, Shifen; Heberling, Shawn

2002-05-17

A simple sample preconcentration technique employing microwave-based evaporation for the determination of trace level bromate and perchlorate in drinking water with ion chromatography is presented. With a hydrophilic anion-exchange column and a sodium hydroxide eluent in linear gradient, bromate and perchlorate can be determined in one injection within 35 min. Prior to ion chromatographic analysis, the drinking water sample was treated with an OnGuard-Ag cartridge to remove the superfluous chloride and concentrated 20-fold using a PTFE beaker in a domestic microwave oven for 15 min. The recoveries of the anions ranged from 94.6% for NO2- to 105.2% for F-. The detection limits for bromate, perchlorate, iodate and chlorate were 0.1, 0.2, 0.1 and 0.2 microg/l, respectively. The developed method is applicable for the quantitation of bromate and perchlorate in drinking water samples.

Integrative assessment of multiple pesticides as risk factors for non-Hodgkin's lymphoma among men

PubMed Central

De Roos, A J; Zahm, S; Cantor, K; Weisenburger, D; Holmes, F; Burmeister, L; Blair, A

2003-01-01

Methods: During the 1980s, the National Cancer Institute conducted three case-control studies of NHL in the midwestern United States. These pooled data were used to examine pesticide exposures in farming as risk factors for NHL in men. The large sample size (n = 3417) allowed analysis of 47 pesticides simultaneously, controlling for potential confounding by other pesticides in the model, and adjusting the estimates based on a prespecified variance to make them more stable. Results: Reported use of several individual pesticides was associated with increased NHL incidence, including organophosphate insecticides coumaphos, diazinon, and fonofos, insecticides chlordane, dieldrin, and copper acetoarsenite, and herbicides atrazine, glyphosate, and sodium chlorate. A subanalysis of these "potentially carcinogenic" pesticides suggested a positive trend of risk with exposure to increasing numbers. Conclusion: Consideration of multiple exposures is important in accurately estimating specific effects and in evaluating realistic exposure scenarios. PMID:12937207

21 CFR 184.1784 - Sodium propionate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium propionate. 184.1784 Section 184.1784 Food... Specific Substances Affirmed as GRAS § 184.1784 Sodium propionate. (a) Sodium propionate (C3H5NaO2, CAS Reg. No. 137-40-6) is the sodium salt of propionic acid. It occurs as colorless, transparent crystals or a...

21 CFR 184.1784 - Sodium propionate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium propionate. 184.1784 Section 184.1784 Food... GRAS § 184.1784 Sodium propionate. (a) Sodium propionate (C3H5NaO2, CAS Reg. No. 137-40-6) is the sodium salt of propionic acid. It occurs as colorless, transparent crystals or a granular crystalline...

21 CFR 184.1784 - Sodium propionate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium propionate. 184.1784 Section 184.1784 Food... Specific Substances Affirmed as GRAS § 184.1784 Sodium propionate. (a) Sodium propionate (C3H5NaO2, CAS Reg. No. 137-40-6) is the sodium salt of propionic acid. It occurs as colorless, transparent crystals or a...

21 CFR 184.1784 - Sodium propionate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium propionate. 184.1784 Section 184.1784 Food... Specific Substances Affirmed as GRAS § 184.1784 Sodium propionate. (a) Sodium propionate (C3H5NaO2, CAS Reg. No. 137-40-6) is the sodium salt of propionic acid. It occurs as colorless, transparent crystals or a...

21 CFR 184.1784 - Sodium propionate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium propionate. 184.1784 Section 184.1784 Food... Specific Substances Affirmed as GRAS § 184.1784 Sodium propionate. (a) Sodium propionate (C3H5NaO2, CAS Reg. No. 137-40-6) is the sodium salt of propionic acid. It occurs as colorless, transparent crystals or a...

Effects of chlorate on the sulfation process of Trypanosoma cruzi glycoconjugates. Implication of parasite sulfates in cellular invasion.

PubMed

Ferrero, Maximiliano R; Soprano, Luciana L; Acosta, Diana M; García, Gabriela A; Esteva, Mónica I; Couto, Alicia S; Duschak, Vilma G

2014-09-01

Sulfation, a post-translational modification which plays a key role in various biological processes, is inhibited by competition with chlorate. In Trypanosoma cruzi, the agent of Chagas' disease, sulfated structures have been described as part of glycolipids and we have reported sulfated high-mannose type oligosaccharides in the C-T domain of the cruzipain (Cz) glycoprotein. However, sulfation pathways have not been described yet in this parasite. Herein, we studied the effect of chlorate treatment on T. cruzi with the aim to gain some knowledge about sulfation metabolism and the role of sulfated molecules in this parasite. In chlorate-treated epimastigotes, immunoblotting with anti-sulfates enriched Cz IgGs (AS-enriched IgGs) showed Cz undersulfation. Accordingly, a Cz mobility shift toward higher isoelectric points was observed in 2D-PAGE probed with anti-Cz antibodies. Ultrastructural membrane abnormalities and a significant decrease of dark lipid reservosomes were shown by electron microscopy and a significant decrease in sulfatide levels was confirmed by TLC/UV-MALDI-TOF-MS analysis. Altogether, these results suggest T. cruzi sulfation occurs via PAPS. Sulfated epitopes in trypomastigote and amastigote forms were evidenced using AS-enriched IgGs by immunoblotting. Their presence on trypomastigotes surface was demonstrated by flow cytometry and IF with Cz/dCz specific antibodies. Interestingly, the percentage of infected cardiac HL-1 cells decreased 40% when using chlorate-treated trypomastigotes, suggesting sulfates are involved in the invasion process. The same effect was observed when cells were pre-incubated with dCz, dC-T or an anti-high mannose receptor (HMR) antibody, suggesting Cz sulfates and HMR are also involved in the infection process by T. cruzi. Copyright © 2014 Elsevier B.V. All rights reserved.

[Subtype classification of ceftriaxone sodium and its influence on the quality of product].

PubMed

Xue, Jing; Jia, Yan-Hua; Li, Jin; Yin, Li-Hui; Hu, Chang-Qin

2014-07-01

Powder X-ray diffraction (PXRD) technology combined with cluster analysis method was used to classify 75 batches of crystalline ceftriaxone sodium into subtypes, the crystalline characteristics of each subtype were measured with scanning electron microscope (SEM). By comparing some parameters of these subtypes correlated to crystallization process of ceftriaxone sodium, such as salification rate, water content in different subtypes, as well as by studying different lattice stabilities, different compatibilities with rubber closures during accelerated stability tests, the key point to improve the quality of domestic ceftriaxone sodium was disclosed. The results of this paper indicated that the fine structure of the products could be controlled well by improving the salification and crystallization process. As a result, the subtype II of ceftriaxone sodium with high stability can be produced.

Potential for chlorate interference in ion chromatographic determination of total nitrogen in natural waters following alkaline persulfate digestion.

PubMed

Halstead, J A; Edwards, J; Soracco, R J; Armstrong, R W

1999-10-01

Determination of total nitrogen in aqueous samples after thermal potassium peroxydisulfate (persulfate) digestion is a commonly used alternative to the tedious Kjeldahl procedure. When ion chromatography is used to quantify the nitrate formed during digestion, there is a potential for interference from a chlorate peak if the digested sample initially contained chloride in concentrations close to or greater than the concentration of nitrogen. It was determined that this interference can be avoided either by using chromatographic conditions which cleanly resolve the nitrate and chlorate peaks (e.g., the Dionex AG9-HG column) or by using digestion reagent concentrations chosen to maintain a high pH throughout the digestion. The second alternative is not a viable option for investigators using a single digestion for both total nitrogen (TN) and total phosphorus (TP) analysis.

Process and apparatus for obtaining silicon from fluosilicic acid

DOEpatents

Sanjurjo, Angel

1988-06-28

Process and apparatus for producing low cost, high purity solar grade silicon ingots in single crystal or quasi single crystal ingot form in a substantially continuous operation in a two stage reactor starting with sodium fluosilicate and a metal more electropositive than silicon (preferably sodium) in separate compartments having easy vapor transport therebetween and thermally decomposing the sodium fluosilicate to cause formation of substantially pure silicon and a metal fluoride which may be continuously separated in the melt and silicon may be directly and continuously cast from the melt.

METHOD OF PROCESSING MONAZITE SAND

DOEpatents

Calkins, G.D.

1957-10-29

A method is given for the pretreatment of monazite sand with sodium hydroxide. When momazite sand is reacted with sodium hydroxide, the thorium, uranium, and rare earths are converted to water-insoluble hydrous oxides; but in the case of uranium, the precipitate compound may at least partly consist of a slightly soluble uranate. According to the patent, monazite sand is treated with an excess of aqueous sodium hydroxide solution, and the insoluble compounds of thorium, uranium, and the rare earths are separated from the aqueous solution. This solution is then concentrated causing sodium phosphate to crystallize out. The crystals are removed from the remaining solution, and the solution is recycled for reaction with a mew supply of momazite sand.

Thyroxine revisited.

PubMed

Katrusiak, Andrzej; Katrusiak, Anna

2004-12-01

The crystal structure of the common therapeutic agent, the pentahydrated sodium salt of L-thyroxine hormone (3-[4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl]-L-alanine), has been determined and discussed in relation to the drug's stability. The stoichiometry and absolute configuration (-)-C(8)S-[C15H10I4NO4]-.Na+.5H2O have been confirmed. The crystals are built of a three-dimensional supramolecular network with two symmetry-independent L-thyroxine anions, in two distinct conformations not previously reported, linked by strong NH-O hydrogen bonds into dimers. Two independent sodium cations are fivefold and sixfold coordinated. The cations and two independent water molecules not involved in coordinating the Na cations form sheets along the crystallographic (001) planes. The presence of differently coordinated cations and non-coordinating water molecules may be responsible for water transport and loss, for decay of the crystals, and subsequent low stability of the drug. Only a conglomerate could be obtained when racemic sodium thyroxine was crystallized from ethanol and methanol solutions by evaporation, which explains the equal penta-hydration of the sodium salts of enantiomorphic and racemic thyroxine, and the fact that there are no apparent differences in their stability. (c) 2004 Wiley-Liss, Inc. and the American Pharmacists Association

Locating Materials with Nuclear Quadrupole Moments within Surface Coil Array Area

DTIC Science & Technology

2015-08-11

location and dimension of the material can determined based on the nuclear quadrupole resonance ( NQR ) signal strength from the surface coil in the array...28.1MHz NQR frequency from potassium chlorate (PC) sample at room temperature. The PC sample will be in different locations parallel to the surface...using the experimental results from the dual surface coil array. 15. SUBJECT TERMS NQR , potassium chlorate, surface coil, surface probe, decoupling

An Examination of Binder Systems and Their Influences on Burn Rates of High-Nitrogen Containing Formulations

DTIC Science & Technology

2011-01-01

sought-after to advance existing HHS technology. Currently existing HHS candle formulations contain significant amounts of potassium perchlorate...Defense spends tens of billions of dollars annually on per- chlorate remediation efforts. Therefore, efforts to elimi- nate perchlorate from military...develop per- chlorate -free formulations of the M126A1 red star para- chute. To maximize the performance of these formula- tions, KClO4 was replaced

Determination of trace aluminum by fluorescence quenching method based on catalysis of potassium chlorate oxidizing alizarin red

NASA Astrophysics Data System (ADS)

Shao-Qin, Lin; Xuan, Lin; Shi-Rong, Hu; Li-Qing, Zeng; Yan, Wang; Li, Chen; Jia-Ming, Liu; Long-Di, Li

2005-11-01

A new method for the determination of trace aluminum has been proposed. It is based on the fact that alizarin red can emit strong and stable fluorescence at 80 °C for 30 min and Al 3+ can effectively catalyze potassium chlorate oxidizing alizarin red to form non-fluorescence complex which cause the fluorescence quenching. The linear dynamic range of this method is 0.040-4.00 ng l -1 with a detection limit of 5.3 pg l -1. The regression equation can be expressed as Δ If = 8.731 + 21.73 c (ng l -1), with the correlation coefficient r = 0.9992 ( n = 6). This sensitive, rapid and accurate method has been applied to the determination of trace aluminum(III) in human hair and tea samples successfully. What is more, the mechanism of catalyzing potassium chlorate oxidizing alizarin red by the fluorescence quenching method is also discussed.

Determination of trace aluminum by fluorescence quenching method based on catalysis of potassium chlorate oxidizing alizarin red.

PubMed

Shao-Qin, Lin; Xuan, Lin; Shi-Rong, Hu; Li-Qing, Zeng; Yan, Wang; Li, Chen; Jia-Ming, Liu; Long-Di, Li

2005-11-01

A new method for the determination of trace aluminum has been proposed. It is based on the fact that alizarin red can emit strong and stable fluorescence at 80 degrees C for 30 min and Al(3+) can effectively catalyze potassium chlorate oxidizing alizarin red to form non-fluorescence complex which cause the fluorescence quenching. The linear dynamic range of this method is 0.040-4.00 ngl(-1) with a detection limit of 5.3 pgl(-1). The regression equation can be expressed as DeltaI(f)=8.731+21.73c(Al(3+)) (ngl(-1)), with the correlation coefficient r=0.9992 (n=6). This sensitive, rapid and accurate method has been applied to the determination of trace aluminum(III) in human hair and tea samples successfully. What is more, the mechanism of catalyzing potassium chlorate oxidizing alizarin red by the fluorescence quenching method is also discussed.

Drowning-out crystallisation of sodium sulphate using aqueous two-phase systems.

PubMed

Taboada, M E; Graber, T A; Asenjo, J A; Andrews, B A

2000-06-23

A novel method to obtain crystals of pure, anhydrous salt, using aqueous two-phase systems was studied. A concentrated salt solution is mixed with polyethylene glycol (PEG), upon which three phases are formed: salt crystals, a PEG-rich liquid and a salt-rich liquid. After removal of the solid salt, a two-phase system is obtained. Both liquid phases are recycled, allowing the design of a continuous process, which could be exploited industrially. The phase diagram of the system water-Na2SO4-PEG 3350 at 28 degrees C was used. Several process alternatives are proposed and their economic potential is discussed. The process steps needed to produce sodium sulphate crystals include mixing, crystallisation, settling and, optionally, evaporation of water. The yield of sodium sulphate increases dramatically if an evaporation step is used.

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

PubMed Central

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 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 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

Growth, optical, thermal, mechanical and dielectric studies of sodium succinate hexahydrate (β phase) single crystal: A promising third order NLO material

NASA Astrophysics Data System (ADS)

Mageshwari, P. S. Latha; Priya, R.; Krishnan, S.; Joseph, V.; Das, S. Jerome

2016-11-01

A third order nonlinear optical (NLO)single crystals of sodium succinate hexahydrate (SSH) (β phase) has been grown by a slow evaporation growth technique using aqueous solution at ambient temperature. The lattice parameters and morphology of SSH were determined by single crystal X-ray diffraction analysis. SSH crystallizes in centrosymmetric monoclinic system with space group P 21 / c and the crystalline purity was analyzed by powder X-ray diffraction analysis. The UV-vis-NIR spectrum reveals that the crystal is transparent in the entire visible region. The recorded FT-IR spectrum verified the presence of various functional groups in the material. NMR analysis of the grown crystal confirms the structural elucidation and detects the major and minor functional groups present in the title compound. ICP-OES analysis proved the presence of sodium in SSH. TG-DTA/DSCanalysis was used to investigate the thermal stability of the material. The dielectric permittivity and dielectric loss of SSH were carried out as a function of frequency for different temperatures and the results were discussed. The mechanical stability was evaluated from Vicker's microhardness test. The third order nonlinear optical properties of SSH has been investigated employing Z-scan technique with He-Ne laser operating at 632.8 nm wavelength.

Pattern of Hydroxyapatite Crystal Growth on Bleached Enamel Following the Application of Two Antioxidants: An Atomic Force Microscope Study.

PubMed

Bhusari, Chitra P; Sharma, Divya S

This study observed the topographical pattern of hydroxyapatite deposition and growth (D&G) on bleached enamel following application of two antioxidants (sodium ascorbate and catalase) using atomic force microscope. Twenty enamel specimens (4×3×2mm), prepared from extracted impacted third molars, were mounted in self-cure acrylic and randomly grouped as: Group I-untreated; Group II- 35%H 2 O 2 ; Group III- 35%H 2 O 2 + artificial saliva; Group IV- 35%H 2 O 2 + catalase+ artificial saliva; Group V- 35%H 2 O 2 + sodium ascorbate+ artificial saliva. Groups I and II were observed immediately after treatment. Groups III-V were observed after 72 hrs. Roughness average was also calculated and analyzed with non-parametric Kruskall-Wallis ANOVA and Mann-Whitney tests. H 2 O 2 dissolved matrix, exposed hydroxyapatite crystals (HACs), causing dissolution on the sides of and within HACs and opening up of nano-spaces. Artificial saliva showed growth of dissoluted crystals. Antioxidants+saliva showed potentiated remineralization by D&G on dissoluted HACs of bleached enamel. Catalase potentiated blockshaped, while sodium ascorbate the needle-shaped crystals with stair-pattern of crystallization. Evidence of oxygen bubbles was a new finding with catalase. Maximum roughness average was in group V followed by group II > group IV > group III > group I. Post-bleaching application of catalase and sodium ascorbate potentiated remineralization by saliva, but in different patterns. None of the tested antioxidant could return the original topography of enamel.

Peculiarities of Crystallization of the Restriction Endonuclease EcoRII

NASA Technical Reports Server (NTRS)

Karpove, Elizaveta; Pusey, M.arc L.

1998-01-01

Nucleases interfere with most standard molecular biology procedures. We have purified and crystallized the restriction endonuclease EcoRII, which belongs to the type II of restriction- modification enzyme, to study the protein crystallization process using a "non standard" macromolecule. A procedure for the purification of EcoRII was developed and 99% pure protein as determined by SDS PAGE electrophoresis obtained. Light scattering experiments were performed to assist in screening protein suitable crystallization conditions. The second virial coefficient was determined as a function of precipitating salt concentration, using sodium chloride, ammonium sulfate, and sodium sulfate. Small (maximum size approximately 0.2 mm) well shaped crystals have been obtained. Larger poorly formed crystals (ca 0.5 mm) have also been obtained, but we have been unable to mount them for diff-raction analysis due to their extreme fragility. Crystallization experiments with PEG have shown that using this precipitant, the best crystals are obtained from slightly over-saturated solutions. Use of higher precipitant concentration leads to dendritic crystal formation. EcoRII is difficult to solubilize and meticulous attention must be paid to the presence of reducing agents.

Application of Solid-State NMR to Reveal Structural Differences in Cefazolin Sodium Pentahydrate from Different Manufacturing Processes

NASA Astrophysics Data System (ADS)

Tian, Ye; Wang, Wei D.; Zou, Wen-Bo; Qian, Jian-Qin; Hu, Chang-Qin

2018-04-01

The solid form of an active pharmaceutical ingredient is important when developing a new chemical entity. A solid understanding of the crystal structure and morphology that affect the mechanical and physical characteristics of pharmaceutical powders determines the manufacturing process. Solid-state NMR, thermogravimetric analysis, X-ray diffraction, and Fourier-transform infrared spectroscopy were combined with theoretical calculation to investigate different crystal packings of α-cefazolin sodium from three different vendors and conformational polymorphism was identified to exist in the α-cefazolin sodium. Marginal differences observed among CEZ-Na pentahydrate 1, 2, and 3 were speculated as the proportion of conformation 2. Understanding the differences in the polymorphic structure of α-cefazolin sodium may help with making modifications to incorporate new knowledge with a product’s development.

Crystal Structure of a Fibroblast Growth Factor Homologous Factor (FHF) Defines a Conserved Surface on FHFs for Binding and Modulation of Voltage-gated Sodium Channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goetz, R.; Dover, K; Laezza, F

2009-01-01

Voltage-gated sodium channels (Nav) produce sodium currents that underlie the initiation and propagation of action potentials in nerve and muscle cells. Fibroblast growth factor homologous factors (FHFs) bind to the intracellular C-terminal region of the Nav alpha subunit to modulate fast inactivation of the channel. In this study we solved the crystal structure of a 149-residue-long fragment of human FHF2A which unveils the structural features of the homology core domain of all 10 human FHF isoforms. Through analysis of crystal packing contacts and site-directed mutagenesis experiments we identified a conserved surface on the FHF core domain that mediates channel bindingmore » in vitro and in vivo. Mutations at this channel binding surface impaired the ability of FHFs to co-localize with Navs at the axon initial segment of hippocampal neurons. The mutations also disabled FHF modulation of voltage-dependent fast inactivation of sodium channels in neuronal cells. Based on our data, we propose that FHFs constitute auxiliary subunits for Navs.« less

Crystal growth of cholesterol in hydrogels and its characterization

NASA Astrophysics Data System (ADS)

Manuel Bravo-Arredondo, J.; Moreno, A.; Mendoza, M. E.

2014-09-01

In this work, we report the crystallization of cholesterol in ethanol solution and in three different hydrogel media: tetramethyl orthosilane, sodium metasilicate, and poly(vinyl)alcohol, whose structures are similar to the gel-like polymer structure of mucin, which is found in the mucus present in bile stone formation. The monohydrated triclinic phase was identified in all the samples by means of X-ray powder diffraction. The characteristic polymorphic crystalline transition of the anhydrous cholesterol was detected by differential thermal analysis and modulated differential scanning calorimetry only in crystals grown in ethanol, sodium silicate, and tetramethyl orthosilane. Finally, hysteresis of the phase transition temperature was measured by modulated differential scanning calorimetry in crystals grown in ethanol. The biological implications of the crystallization of cholesterol for bile stones formation are discussed in the last part of this contribution.

A chlorate candle/lithium hydroxide personal breathing apparatus

NASA Technical Reports Server (NTRS)

Martin, F. E.

1972-01-01

A portable coal mine rescue and survival equipment is reported that consists of a chlorate candle with a lithium hydroxide carbon-dioxide absorbent for oxygen generation, a breathing bag and tubing to conduct breathing to and from the man. A plastic hood incorporating a mouth piece for communication provides also eye protection and prevents inhalation through the nose. Manned testing of a prototype system demonstrated the feasibility of this closed circuit no-maintenance breathing apparatus that provides for good voice communication.

High-Nitrogen-Based Pyrotechnics: Development of Perchlorate-Free Green-Light Illuminants for Military and Civilian Applications

DTIC Science & Technology

2012-01-01

Table 1. Magnesium served as the main fuel in the formulation, barium nitrate and potassium per- chlorate served as the oxidizers, and dechlorane plus...course of the investigation needed to be changed. Although the initial investigation set out to remove potassium per- chlorate oxidizer from the M195 HHS...become a concern of the US Department of Defense is the “perchlorate issue.” Potassium perchlorate and ammonium perchlorate oxidizers, once believed to be

Influence of calcium ions on the crystallization of sodium bicarbonate

NASA Astrophysics Data System (ADS)

Zhu, Yi; Demilie, Paul; Davoine, Perrine; Cartage, Thierry; Delplancke-Ogletree, Marie-Paule

2005-02-01

In industrial crystallization of sodium bicarbonate (sodium hydrogenocarbonate), the presence of calcium ions in solutions is unavoidable due to the production process. The understanding of the Ca 2+ role in NaHCO 3 crystallization would be helpful for improving the quality of the final products. The influence of calcium ions on NaHCO 3 crystallization was investigated in a 5-l mixed suspension mixed product removal crystallizer under controlled conditions. A density meter was used for continuous supersaturation monitoring. After a steady state had been reached, different CaCl 2 amounts were added at a constant flow rate. It was found that limited calcium ion levels in the system reduce drastically the nucleation frequency of NaHCO 3 and has a limited influence on crystal growth rate. The supersaturation measurements and other methods confirmed this phenomenon. The relationship between the Ca 2+ influence on NaHCO 3 crystallization, the calcium carbonate solubility and its metastable zone in concentrated NaHCO 3 solution was established. In fact, Ca 2+ has a maximum effect on NaHCO 3 crystallization kinetics when the saturation of calcium carbonate in NaHCO 3 solution has been reached, and the effect is constant in the metastable zone. The excess of Ca 2+ precipitates in NaHCO 3 solution as CaCO 3, as observed by energy dispersive X-ray and X-ray diffraction. This explained why an increasing Ca 2+ concentration in the solution has a limited influence on NaHCO 3 crystal size distribution and habit, but decreases the crystal purity. It is also confirmed that an impurity as Ca 2+ has no influence on the equilibrium NaHCO 3-Na 2CO 3.

The influence of sodium lauryl sulfate on the crystal phases of titania by hydrothermal method

NASA Astrophysics Data System (ADS)

Liu, Chaohong; Wang, Xin

2012-11-01

In this paper, we prepared TiO2 nanostructures by a hydrothermal method and investigated the influence of the SO4^{2-} ion and the effect of long alkyl chains of sodium dodecyl sulfate on the crystal phases of TiO2 by experiments and theoretical calculations. The results indicate that the absorption of the H+HSO4 fragment on rutile (110) is more stable than that of the 2H+SO4 fragment and more favorable to the formation of anatase. The absorption and steric effects of sodium dodecyl sulfate on the surfaces of TiO2 grains also have an important influence on the formation of mixed crystals by changing the speed and the way of octahedral TiO6 units combining. Based on the above facts, we revised the original reaction scheme for crystalline titania formation by previous authors.

Suicidal intoxication with potassium chlorate successfully treated with renal replacement therapy and extracorporeal liver support.

PubMed

Sein Anand, Jacek; Barwina, Małgorzata; Zajac, Maciej; Kaletha, Krystian

2012-01-01

We present a case of a 22-year-old male who, in a suicide attempt, ingested approximately 200 g of potassium chlorate. Upon admission to the hospital, he presented in full respiratory failure with cyanosis. Methylene blue antidote was given but found to be ineffective. The patient was intubated and mechanical ventilation was initiated. Because of renal failure with anuria, intermittent haemodialysis (iHD) followed by continuous venovenous hemodiafiltration (CVVHDF) was performed. His hospital stay was also complicated by hemolysis, disseminated intravascular coagulation, and atrial fibrillation. Transfusions of packed red blood cells, platelets, and fresh frozen plasma were necessary to correct the deficits. He also developed liver failure and required two sessions of molecular adsorbent recirculating system (MARS) therapy. On day 14 of his hospitalization, he regained consciousness, as well as full respiratory and circulatory function. There are no controlled studies addressing management of potassium chlorate poisoning. We suggest that early renal replacement therapy should be strongly considered.

Axial vibration control of melt structure of sodium nitrate in crystal growth process

NASA Astrophysics Data System (ADS)

Sadovskiy, Andrey; Sukhanova, Ekaterina; Belov, Stanislav; Kostikov, Vladimir; Zykova, Marina; Artyushenko, Maxim; Zharikov, Evgeny; Avetissov, Igor

2015-05-01

The melt structure evolution under the action of the low-frequency axial vibration control (AVC) technique was studied in situ by Raman spectroscopy for several complex chemical compound melts: sodium nitrate, margarine acid, paraffin mixture (C17-C20). The measurements were conducted in the temperature range from the melting point up to 60 °C above. Comparison of crystallization heats for AVC activated and steady melts with melting heats of AVC-CZ and conventional CZ produced powders allowed to propose the energy diagram of NaNO3 states for activated and non-activated melts and crystals based on DTA, XRD, DSC and Raman experimental data.

Metabolic primers for detection of (Per)chlorate-reducing bacteria in the environment and phylogenetic analysis of cld gene sequences.

PubMed

Bender, Kelly S; Rice, Melissa R; Fugate, William H; Coates, John D; Achenbach, Laurie A

2004-09-01

Natural attenuation of the environmental contaminant perchlorate is a cost-effective alternative to current removal methods. The success of natural perchlorate remediation is dependent on the presence and activity of dissimilatory (per)chlorate-reducing bacteria (DPRB) within a target site. To detect DPRB in the environment, two degenerate primer sets targeting the chlorite dismutase (cld) gene were developed and optimized. A nested PCR approach was used in conjunction with these primer sets to increase the sensitivity of the molecular detection method. Screening of environmental samples indicated that all products amplified by this method were cld gene sequences. These sequences were obtained from pristine sites as well as contaminated sites from which DPRB were isolated. More than one cld phylotype was also identified from some samples, indicating the presence of more than one DPRB strain at those sites. The use of these primer sets represents a direct and sensitive molecular method for the qualitative detection of (per)chlorate-reducing bacteria in the environment, thus offering another tool for monitoring natural attenuation. Sequences of cld genes isolated in the course of this project were also generated from various DPRB and provided the first opportunity for a phylogenetic treatment of this metabolic gene. Comparisons of the cld and 16S ribosomal DNA (rDNA) gene trees indicated that the cld gene does not track 16S rDNA phylogeny, further implicating the possible role of horizontal transfer in the evolution of (per)chlorate respiration.

Preparative crystallization of a single chain antibody using an aqueous two-phase system.

PubMed

Huettmann, Hauke; Berkemeyer, Matthias; Buchinger, Wolfgang; Jungbauer, Alois

2014-11-01

A simultaneous crystallization and aqueous two-phase extraction of a single chain antibody was developed, demonstrating process integration. The process conditions were designed to form an aqueous two-phase system, and to favor crystallization, using sodium sulfate and PEG-2000. At sufficiently high concentrations of PEG, a second phase was generated in which the protein crystallization occurred simultaneously. The single chain antibody crystals were partitioned to the top, polyethylene glycol-rich phase. The crystal nucleation took place in the sodium sulfate-rich phase and at the phase boundary, whereas crystal growth was progressing mainly in the polyethylene glycol-rich phase. The crystals in the polyethylene glycol-rich phase grew to a size of >50 µm. Additionally, polyethylene glycol acted as an anti-solvent, thus, it influenced the crystallization yield. A phase diagram with an undersaturation zone, crystallization area, and amorphous precipitation zone was established. Only small differences in polyethylene glycol concentration caused significant shifts of the crystallization yield. An increase of the polyethylene glycol content from 2% (w/v) to 4% (w/v) increased the yield from approximately 63-87%, respectively. Our results show that crystallization in aqueous two-phase systems is an opportunity to foster process integration. © 2014 Wiley Periodicals, Inc.

Simultaneous determination of inorganic anions and cations in explosive residues by ion chromatography.

PubMed

Meng, Hong-Bo; Wang, Tian-Ran; Guo, Bao-Yuan; Hashi, Yuki; Guo, Can-Xiong; Lin, Jin-Ming

2008-07-15

A non-suppressed ion chromatographic method by connecting anion-exchange and cation-exchange columns directly was developed for the separation and determination of five inorganic anions (sulfate, nitrate, chloride, nitrite, and chlorate) and three cations (sodium, ammonium, and potassium) simultaneously in explosive residues. The mobile phase was composed of 3.5mM phthalic acid with 2% acetonitrile and water at flow rate of 0.2 mL/min. Under the optimal conditions, the eight inorganic ions were completely separated and detected simultaneously within 16 min. The limits of detection (S/N=3) of the anions and cations were in the range of 50-100 microg/L and 150-320 microg/L, respectively, the linear correlation coefficients were 0.9941-0.9996, and the R.S.D. of retention time and peak area were 0.10-0.29% and 5.65-8.12%, respectively. The method was applied successfully to the analysis of the explosive samples with satisfactory results.

[Determination of inorganic ions in explosive residues by capillary zone electrophoresis].

PubMed

Feng, Junhe; Guo, Baoyuan; Lin, Jin-Ming; Xu, Jianzhong; Zhou, Hong; Sun, Yuyou; Liu, Yao; Quan, Yangke; Lu, Xiaoming

2008-11-01

Five anions (chlorate, perchlorate, nitrate, nitrite, and sulfate) and two cations (ammonium and potassium) in explosive residues have been separated and determined by capillary zone electrophoresis (CZE) with indirect ultraviolet detection. The electrolyte buffer for the cation separation was 10 mmol/L pyridine (pH 4.5) -3 mmol/L 18-crown-6-ether. Ammonium and potassium ions were baseline separated in less than 2.6 min with the detection limits of 0.10 mg/L and 0.25 mg/L (S/N = 3), respectively. The electrolyte buffer for the anion separation consisted of 40 mmol/L boric acid-1.8 mmol/L potassium dichromate-2 mmol/L sodium tetraborate (pH 8.6), and tetramethyl ammonium hydroxide (TMAOH) was used as electroosmotic flow modifier. All five anions were well separated in less than 4.6 min with the detection limit range of 0.10 - 1.85 mg/L (S/N = 3). The method was successfully used in real sample investigations to confirm the type of explosives.

Integrative assessment of multiple pesticides as risk factors for non-Hodgkin's lymphoma among men.

PubMed

De Roos, A J; Zahm, S H; Cantor, K P; Weisenburger, D D; Holmes, F F; Burmeister, L F; Blair, A

2003-09-01

An increased rate of non-Hodgkin's lymphoma (NHL) has been repeatedly observed among farmers, but identification of specific exposures that explain this observation has proven difficult. During the 1980s, the National Cancer Institute conducted three case-control studies of NHL in the midwestern United States. These pooled data were used to examine pesticide exposures in farming as risk factors for NHL in men. The large sample size (n = 3417) allowed analysis of 47 pesticides simultaneously, controlling for potential confounding by other pesticides in the model, and adjusting the estimates based on a prespecified variance to make them more stable. Reported use of several individual pesticides was associated with increased NHL incidence, including organophosphate insecticides coumaphos, diazinon, and fonofos, insecticides chlordane, dieldrin, and copper acetoarsenite, and herbicides atrazine, glyphosate, and sodium chlorate. A subanalysis of these "potentially carcinogenic" pesticides suggested a positive trend of risk with exposure to increasing numbers. Consideration of multiple exposures is important in accurately estimating specific effects and in evaluating realistic exposure scenarios.

Meat Science and Muscle Biology Symposium: Ecological and dietary impactors of foodborne pathogens and methods to reduce fecal shedding in cattle.

PubMed

Callaway, T R; Edrington, T S; Nisbet, D J

2014-04-01

Pathogenic bacteria can live asymptomatically within and on cattle and can enter the food chain but also can be transmitted to humans by fecal or direct animal contact. Reducing pathogenic bacterial incidence and populations within live cattle represents an important step in improving food safety. A broad range of preslaughter intervention strategies are being developed, which can be loosely classified as 1) directly antipathogen strategies, 2) competitive enhancement strategies (that use the microbiome's competitive nature against pathogens), and 3) animal management strategies. Included within these broad categories are such diverse methods as vaccination against foodborne pathogens, probiotics and prebiotics, bacterial viruses (i.e., bacteriophages), sodium chlorate feeding, and dietary and management changes that specifically alter the microbiome. The simultaneous application of 1 or more preharvest strategies has the potential to reduce human foodborne illnesses by erecting multiple hurdles preventing entry into humans. However, economic factors that govern producer profitability must be kept in mind while improving food safety.

Superionic glass-ceramic electrolytes for room-temperature rechargeable sodium batteries.

PubMed

Hayashi, Akitoshi; Noi, Kousuke; Sakuda, Atsushi; Tatsumisago, Masahiro

2012-05-22

Innovative rechargeable batteries that can effectively store renewable energy, such as solar and wind power, urgently need to be developed to reduce greenhouse gas emissions. All-solid-state batteries with inorganic solid electrolytes and electrodes are promising power sources for a wide range of applications because of their safety, long-cycle lives and versatile geometries. Rechargeable sodium batteries are more suitable than lithium-ion batteries, because they use abundant and ubiquitous sodium sources. Solid electrolytes are critical for realizing all-solid-state sodium batteries. Here we show that stabilization of a high-temperature phase by crystallization from the glassy state dramatically enhances the Na(+) ion conductivity. An ambient temperature conductivity of over 10(-4) S cm(-1) was obtained in a glass-ceramic electrolyte, in which a cubic Na(3)PS(4) crystal with superionic conductivity was first realized. All-solid-state sodium batteries, with a powder-compressed Na(3)PS(4) electrolyte, functioned as a rechargeable battery at room temperature.

Robust diamond-like Fe-Si network in the zero-strain Na xFeSiO 4 cathode

DOE PAGES

Ye, Zhuo; Zhao, Xin; Li, Shouding; ...

2016-07-14

Sodium orthosilicates Na 2 MSiO 4 ( M denotes transition metals) have attracted much attention due to the possibility of exchanging two electrons per formula unit. In this work, we report a group of sodium iron orthosilicates Na 2FeSiO 4. Their crystal structures are characterized by a diamond-like Fe-Si network. The Fe-Si network is quite robust against the charge/discharge process, which explains the high structural stability observed in experiment. Furthermore, using the density functional theory within the GGA + U framework and X-ray diffraction studies, the crystal structures and structural stabilities during the sodium extraction/re-insertion process are systematically investigated.

Structural characterization and physicochemical features of new hybrid compound containing chlorate anions of cadmate (II)

NASA Astrophysics Data System (ADS)

Lassoued, Mohamed Saber; Abdelbaky, Mohammed S. M.; Lassoued, Abdelmajid; Gadri, Abdellatif; Ammar, Salah; Ben Salah, Abdelhamid; García-Granda, Santiago

2017-08-01

The present paper reports the synthesis of a single crystal of a new organic-inorganic hybrid compound, with the formula (C6H14N2) CdCl4·H2O, by slow evaporation method at room temperature. It was characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), Hirshfeld surface, spectroscopy measurement, thermal study and photoluminescence (PL) properties. A preliminary SCXRD structural analysis revealed that it crystallized in the monoclinic system (space group P21/c) with the following unit cell parameters: a = 12.95823(16) Å, b = 14.92449(16) Å, c = 7.13838(9) Å and β = 103.2108(12)° with Z = 4. The refinement converged to R = 0.0164 and ωR = 0.0393. Its atomic arrangement can be described as an alternation of organic and inorganic layers along the a-axis. The crystal packing was governed by the N-H⋯Cl and O-H⋯Cl hydrogen bonding interaction between the 1.2-diammoniumcyclohexane cations, the [CdCl42n-]n anions and water molecule. The Hirshfeld surface analysis was conducted to investigate intermolecular interactions and associated 2D fingerprint plots, revealing the relative contribution of these interactions in the crystal structure quantitatively. Furthermore, the room temperature infrared (IR) spectrum of the title compound was recorded and analyzed on the basis of data found in the literature. Besides, the thermal analysis studies were performed, but no phase transition was found in the temperature range between 30 and 450 °C. The optical and PL properties of the compound were investigated in the solid state at room temperature and exhibited three bands at 225, 268 and 315 nm and a strong fluorescence at 443 nm.

Citrate, not phosphate, can dissolve calcium oxalate monohydrate crystals and detach these crystals from renal tubular cells.

PubMed

Chutipongtanate, Somchai; Chaiyarit, Sakdithep; Thongboonkerd, Visith

2012-08-15

Dissolution therapy of calcium oxalate monohydrate (COM) kidney stone disease has not yet been implemented due to a lack of well characterized COM dissolution agents. The present study therefore aimed to identify potential COM crystal dissolution compounds. COM crystals were treated with deionized water (negative control), 5 mM EDTA (positive control), 5 mM sodium citrate, or 5mM sodium phosphate. COM crystal dissolution activities of these compounds were evaluated by phase-contrast and video-assisted microscopic examinations, semi-quantitative analysis of crystal size, number and total mass, and spectrophotometric oxalate-dissolution assay. In addition, effects of these compounds on detachment of COM crystals, which adhered tightly onto renal tubular cell surface, were also investigated. The results showed that citrate, not phosphate, had a significant dissolution effect on COM crystals as demonstrated by significant reduction of crystal size (approximately 37% decrease), crystal number (approximately 53% decrease) and total crystal mass (approximately 72% decrease) compared to blank and negative controls. Spectrophotometric oxalate-dissolution assay successfully confirmed the COM crystal dissolution property of citrate. Moreover, citrate could detach up to 85% of the adherent COM crystals from renal tubular cell surface. These data indicate that citrate is better than phosphate for dissolution and detachment of COM crystals. Copyright © 2012 Elsevier B.V. All rights reserved.

Laser-induced Fluorescence Spectroscopy for applications in chemical sensing and optical refrigeration

NASA Astrophysics Data System (ADS)

Kumi Barimah, Eric

Laser-induced breakdown spectroscopy (LIBS) is an innovative technique that has been used as a method for fast elemental analysis in real time. Conventional ultraviolet-visible (UV-VIS) LIBS has been applied to detect the elemental composition of different materials, including explosives, pharmaceutical drugs, and biological samples. The extension of conventional LIBS to the infrared region (˜1-12 mum) promises to provide additional information on molecular emission signatures due to rotational-vibrational transitions. In this research, a pulsed Nd: YAG laser operating at 1064 nm was focused onto several sodium compounds (NaCl, NaClO3, Na2CO3 and NaClO4) and potassium compounds (KCl, KClO3, K2CO3 and KClO4) to produce an intense plasma at the target surface. Several distinct infrared (IR) atomic emission signatures were observed from all sodium and potassium containing compounds. The atomic emission lines observed from the investigated samples matched assigned transitions of neutral sodium and potassium atoms published in the National Institute of Standards and Technology (NIST) atomic database. In addition to the intense atomic lines, the rst evidence of molecular LIBS emission structures were observed at ˜10.0 m in KClO3 and NaClO3 for the chlorate anion (ClO3 --1), at ˜6.7 to 8.0 mum in KNO3 and NaNO 3 for the nitrate anion (NO3--1 ), ˜8.0 to 10.0 mum in KClO4 and NaClO4 for perchlorate anion (ClO4--1 ), and ˜6.88 mum and 11.53 mum in Na2CO3 for the carbonate anion (CO3--1 ). The observed molecular emission showed strong correlation with the conventional Fourier Transform Infrared Spectrometry (FTIR) absorption spectra of the investigated samples. IR LIBS was also applied to determine the limit of detection (LOD) for the perchlorate anion in KClO4 using the 8.0 -11.0 mum IR-LIBS emission band. The calibration curve of ClO4 in KClO4 was constructed using peak and integrated emission intensities for known concentrations of mixed KClO4/NH4NO3 samples. The limit of detection for ClO4, was determined to be 14.7 +/- 0.5 wt%/wt for the given experimental conditions. In the second part of this research, the temperature-dependent absorption and emission properties of Tm doped KPb2Cl5 (KPC) and KPb2Br5 (KPB) were evaluated for applications in laser cooling. A Tm doped Y3Al5O12 (YAG) crystal was also included for comparative studies. Under laser pumping, all crystals exhibited broad IR fluorescence at room temperature with a mean fluorescence wavelength of ˜1.82 mum and bandwidth of 0.14 mum (FWHM) for Tm:KPC/KPB and ˜1.79 mum for Tm:YAG. Initial experiments on laser-induced heating/cooling were performed using a combined IR imaging and fluorescence thermometry setup. Employing a continuous-wave laser operating at 1.907 mum, Tm: KPC and Tm: KPB crystals revealed a very small heat load resulting in temperature increase of ˜ 0.3 ( +/- 0.1)°C. The heat loading in Tm:YAG was signicantly larger and resulted in a temperature increase of ˜0.9 (+/-0.1)°C. The results derived from IR imaging were also conrmed by the fluorescence thermometry experiments, which showed only minimal changes in the FIR intensity ratio of the green Er3+ fluorescence lines from Er:KPC.

Sodium chloride crystallization from thin liquid sheets, thick layers, and sessile drops in microgravity

NASA Astrophysics Data System (ADS)

Fontana, Pietro; Pettit, Donald; Cristoforetti, Samantha

2015-10-01

Crystallization from aqueous sodium chloride solutions as thin liquid sheets, 0.2-0.7 mm thick, with two free surfaces supported by a wire frame, thick liquid layers, 4-6 mm thick, with two free surfaces supported by metal frame, and hemispherical sessile drops, 20-32 mm diameter, supported by a flat polycarbonate surface or an initially flat gelatin film, were carried out under microgravity on the International Space Station (ISS). Different crystal morphologies resulted based on the fluid geometry: tabular hoppers, hopper cubes, circular [111]-oriented crystals, and dendrites. The addition of polyethylene glycol (PEG-3350) inhibited the hopper growth resulting in flat-faced surfaces. In sessile drops, 1-4 mm tabular hopper crystals formed on the free surface and moved to the fixed contact line at the support (polycarbonate or gelatin) self-assembling into a shell. Ring formation created by sessile drop evaporation to dryness was observed but with crystals 100 times larger than particles in terrestrially formed coffee rings. No hopper pyramids formed. By choosing solution geometries offered by microgravity, we found it was possible to selectively grow crystals of preferred morphologies.

Effect of glycine on pH changes and protein stability during freeze-thawing in phosphate buffer systems.

PubMed

Pikal-Cleland, Katherine A; Cleland, Jeffrey L; Anchordoquy, Thomas J; Carpenter, John F

2002-09-01

Previous studies have established that the selective precipitation of a less soluble buffer component during freezing can induce a significant pH shift in the freeze concentrate. During freezing of sodium phosphate solutions, crystallization of the disodium salt can produce a pH decrease as great as 3 pH units which can dramatically affect protein stability. The objective of our study was to determine how the presence of glycine (0-500 mM), a commonly used bulking agent in pharmaceutical protein formulations, affects the pH changes normally observed during freezing in sodium phosphate buffer solutions and to determine whether these pH changes contribute to instability of model proteins in glycine/phosphate formulations. During freezing in sodium phosphate buffers, the presence of glycine significantly influenced the pH. Glycine at the lower concentrations (< or = 50 mM) suppressed the pH decrease normally observed during freezing in 10 and 100 mM sodium phosphate buffer, possibly by reducing the nucleation rate of salt and thereby decreasing the extent of buffer salt crystallization. The presence of glycine at higher concentration (> 100 mM) in the sodium phosphate buffer resulted in a more complete crystallization of the disodium salt as indicated by the frozen pH values closer to the equilibrium value (pH 3.6). Although high concentrations of glycine can facilitate more buffer salt crystallization and these pH shifts may prove to be potentially damaging to the protein, glycine, in its amorphous state, can also act to stabilize a protein via the preferential exclusion mechanism. Copyright 2002 Wiley-Liss Inc.

Identification of inorganic improvised explosive devices by analysis of postblast residues using portable capillary electrophoresis instrumentation and indirect photometric detection with a light-emitting diode.

PubMed

Hutchinson, Joseph P; Evenhuis, Christopher J; Johns, Cameron; Kazarian, Artaches A; Breadmore, Michael C; Macka, Miroslav; Hilder, Emily F; Guijt, Rosanne M; Dicinoski, Greg W; Haddad, Paul R

2007-09-15

A commercial portable capillary electrophoresis (CE) instrument has been used to separate inorganic anions and cations found in postblast residues from improvised explosive devices (IEDs) of the type used frequently in terrorism attacks. The purpose of this analysis was to identify the type of explosive used. The CE instrument was modified for use with an in-house miniaturized light-emitting diode (LED) detector to enable sensitive indirect photometric detection to be employed for the detection of 15 anions (acetate, benzoate, carbonate, chlorate, chloride, chlorite, cyanate, fluoride, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate, thiosulfate) and 12 cations (ammonium, monomethylammonium, ethylammonium, potassium, sodium, barium, strontium, magnesium, manganese, calcium, zinc, lead) as the target analytes. These ions are known to be present in postblast residues from inorganic IEDs constructed from ammonium nitrate/fuel oil mixtures, black powder, and chlorate/perchlorate/sugar mixtures. For the analysis of cations, a blue LED (470 nm) was used in conjunction with the highly absorbing cationic dye, chrysoidine (absorption maximum at 453 nm). A nonaqueous background electrolyte comprising 10 mM chrysoidine in methanol was found to give greatly improved baseline stability in comparison to aqueous electrolytes due to the increased solubility of chrysoidine and its decreased adsorption onto the capillary wall. Glacial acetic acid (0.7% v/v) was added to ensure chrysoidine was protonated and to enhance separation selectivity by means of complexation with transition metal ions. The 12 target cations were separated in less than 9.5 min with detection limits of 0.11-2.30 mg/L (calculated at a signal-to-noise ratio of 3). The anions separation system utilized a UV LED (370 nm) in conjunction with an aqueous chromate electrolyte (absorption maximum at 371 nm) consisting of 10 mM chromium(VI) oxide and 10 mM sodium chromate, buffered with 40 mM tris(hydroxymethyl)aminomethane at pH 8.05. All 15 target anions were baseline separated in less than 9 min with limits of detection ranging from 0.24 to 1.15 mg/L (calculated at a signal-to-noise ratio of 3). Use of the portable instrumentation in the field was demonstrated by analyzing postblast residues in a mobile laboratory immediately after detonation of the explosive devices. Profiling the ionic composition of the inorganic IEDs allowed identification of the chemicals used in their construction.

Water-Quality Constituents, Dissolved-Organic-Carbon Fractions, and Disinfection By-Product Formation in Water from Community Water-Supply Wells in New Jersey, 1998-99

USGS Publications Warehouse

Hopple, Jessica A.; Barringer, Julia L.; Koleis, Janece

2007-01-01

Water samples were collected from 20 community water-supply wells in New Jersey to assess the chemical quality of the water before and after chlorination, to characterize the types of organic carbon present, and to determine the disinfection by-product formation potential. Water from the selected wells previously had been shown to contain concentrations of dissolved organic carbon (DOC) that were greater than 0.2 mg/L. Of the selected wells, five are completed in unconfined (or semi-confined) glacial-sediment aquifers of the Piedmont and Highlands (New England) Physiographic Provinces, five are completed in unconfined bedrock aquifers of the Piedmont Physiographic Province, and ten are completed in unconsolidated sediments of the Coastal Plain Physiographic Province. Four of the ten wells in the Coastal Plain are completed in confined parts of the aquifers; the other six are in unconfined aquifers. One or more volatile organic compounds (VOCs) were detected in untreated water from all of the 16 wells in unconfined aquifers, some at concentrations greater than maximum contaminant levels. Those compounds detected included aliphatic compounds such as trichloroethylene and 1,1,1-trichloroethane, aromatic compounds such as benzene, the trihalomethane compound, chloroform, and the gasoline additive methyl tert-butyl ether (MTBE). Concentrations of sodium and chloride in water from one well in a bedrock aquifer and sulfate in water from another exceeded New Jersey secondary standards for drinking water. The source of the sulfate was geologic materials, but the sodium and chloride probably were derived from human inputs. DOC fractions were separated by passing water samples through XAD resin columns to determine hydrophobic fractions from hydrophilic fractions. Concentrations of hydrophobic acids were slightly lower than those of combined hydrophilic acids, neutral compounds, and low molecular weight compounds in most samples. Water samples from the 20 wells were adjusted to a pH of 7, dosed with sodium hypochlorite, and incubated for 168 hours (seven days) at 25 ?C to form disinfection by-products (DBPs). Concentrations of the DBPs-trihalomethanes, haloacetic acids, haloacetonitriles, and chlorate-were measured. Concentrations of these compounds, with few exceptions, were higher in water from Coastal Plain wells than from wells in glacial and bedrock aquifers. The organic-carbon fractions were dosed with sodium hypochlorite, incubated for 168 hours at 25 ?C, and analyzed for trihalomethanes, haloacetic acids, haloacetonitriles, and chlorate. Concentrations of trihalomethanes and haloacetic acids were higher in most of the hydrophobic organic-acid fractions than in the hydrophilic fractions, with the highest concentrations in samples from Coastal Plain aquifers. Traces of haloacetonitriles were measured, mostly in the hydrophilic fraction. The aromaticity of the precursor DOC, as estimated by measurements of the absorbance of ultraviolet light at 254 nanometers, apparently is a factor in the DBP formation potentials determined, as aromaticity was greater in the samples that developed high concentrations of DBPs. VOCs may have contributed to the organic carbon present in some of the samples, but much of the DOC present in water from the 20 wells appeared to be natural in origin. The sediments of the Coastal Plain aquifers, in particular, contain substantial amounts of organic matter, which contribute ammonia, organic nitrogen, and aromatic DOC compounds to the ground water. Thus, the geologic characteristics of the aquifers appear to be a major factor in the potential for ground water to form DBPs when chlorinated.

Crossed-coil detection of two-photon excited nuclear quadrupole resonance

NASA Astrophysics Data System (ADS)

Eles, Philip T.; Michal, Carl A.

2005-08-01

Applying a recently developed theoretical framework for determining two-photon excitation Hamiltonians using average Hamiltonian theory, we calculate the excitation produced by half-resonant irradiation of the pure quadrupole resonance of a spin-3/2 system. This formalism provides expressions for the single-quantum and double-quantum nutation frequencies as well as the Bloch-Siegert shift. The dependence of the excitation strength on RF field orientation and the appearance of the free-induction signal along an axis perpendicular to the excitation field provide an unmistakable signature of two-photon excitation. We demonstrate single- and double-quantum excitation in an axially symmetric system using 35Cl in a single crystal of potassium chlorate ( ωQ = 28 MHz) with crossed-coil detection. A rotation plot verifies the orientation dependence of the two-photon excitation, and double-quantum coherences are observed directly with the application of a static external magnetic field.

The crystal structure of the regulatory domain of the human sodium-driven chloride/bicarbonate exchanger.

PubMed

Alvadia, Carolina M; Sommer, Theis; Bjerregaard-Andersen, Kaare; Damkier, Helle Hasager; Montrasio, Michele; Aalkjaer, Christian; Morth, J Preben

2017-09-21

The sodium-driven chloride/bicarbonate exchanger (NDCBE) is essential for maintaining homeostatic pH in neurons. The crystal structure at 2.8 Å resolution of the regulatory N-terminal domain of human NDCBE represents the first crystal structure of an electroneutral sodium-bicarbonate cotransporter. The crystal structure forms an equivalent dimeric interface as observed for the cytoplasmic domain of Band 3, and thus establishes that the consensus motif VTVLP is the key minimal dimerization motif. The VTVLP motif is highly conserved and likely to be the physiologically relevant interface for all other members of the SLC4 family. A novel conserved Zn 2+ -binding motif present in the N-terminal domain of NDCBE is identified and characterized in vitro. Cellular studies confirm the Zn 2+ dependent transport of two electroneutral bicarbonate transporters, NCBE and NBCn1. The Zn 2+ site is mapped to a cluster of histidines close to the conserved ETARWLKFEE motif and likely plays a role in the regulation of this important motif. The combined structural and bioinformatics analysis provides a model that predicts with additional confidence the physiologically relevant interface between the cytoplasmic domain and the transmembrane domain.

radiation and electric field induced effects on the order-disorder phase in lithium sodium sulphate crystals

NASA Astrophysics Data System (ADS)

Hamed, A. E.; Kassem, M. E.; El-Wahidy, E. F.; El-Abshehy, M. A.

1995-03-01

The temperature dependence of specific heat at constant pressure, Cp(T), has been measured for lithium sodium sulphate, LiNaSo4 crystals, at different ?-radiation doses and external bias electric field (Eb), in the temperature range 300-900 K. A nonlinear dependence of transition temperature, T1 and a remarkable change in the thermodynamic parameters, were obtained as the effect of both electric field and ?-radiation. The effect of ?-radiation doses on the phase transition in LiNaSO4 crystals was explained as due to an internal bias field, Eb, originating from the interaction of polar defects with the order parameter of the host lattice. The internal bias field effect on the behaviour of Cp(T) in LiNaSO4 crystals was similar to that of the external electric field (E).

Integrated Data Collection Analysis (IDCA) Program - AN and Bullseye Smokeless Powder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.

The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of ammonium nitrate (AN) mixed with Bullseye® smokeless powder (Gunpowder). The participants found the AN/Gunpowder to: 1) have a range of sensitivity to impact, comparable to or less than RDX, 2) be fairly insensitive to friction as measured by BAM and ABL, 3) have a range for ESD, from insensitive to more sensitive than PETN, and 4) have thermal sensitivity aboutmore » the same as PETN and Gunpowder. This effort, funded by the Department of Homeland Security (DHS), is putting the issues of safe handling of these materials in perspective with standard military explosives. The study is adding SSST testing results for a broad suite of different HMEs to the literature. Ultimately the study has the potential to suggest new guidelines and methods and possibly establish the SSST testing accuracies needed when developing safe handling practices for HMEs. Each participating testing laboratory uses identical test materials and preparation methods. Note, however, the test procedures differ among the laboratories. The testing performers involved are Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Indian Head Division, Naval Surface Warfare Center, (NSWC IHD), Sandia National Laboratories (SNL), and Air Force Research Laboratory (AFRL/RXQL). These tests are conducted as a proficiency study in order to establish some consistency in test protocols, procedures, and experiments and to compare results when these testing variables cannot be made consistent. Keywords: Small-scale safety testing, proficiency test, impact-, friction-, spark discharge-, thermal testing, round-robin test, safety testing protocols, HME, RDX, potassium perchlorate, potassium chlorate, sodium chlorate, sugar, dodecane, PETN, carbon, ammonium nitrate, Gunpowder, Bullseye® smokeless powder.« less

Soil transport parameters of potassium under a tropical saline soil condition using STANMOD

NASA Astrophysics Data System (ADS)

Suzanye da Silva Santos, Rafaelly; Honorio de Miranda, Jarbas; Previatello da Silva, Livia

2015-04-01

Environmental responsibility and concerning about the final destination of solutes in soil, so more studies allow a better understanding about the solutes behaviour in soil. Potassium is a macronutrient that is required in high concentrations, been an extremely important nutrient for all agricultural crops. It plays essential roles in physiological processes vital for plant growth, from protein synthesis to maintenance of plant water balance, and is available to plants dissolved in soil water while exchangeable K is loosely held on the exchange sites on the surface of clay particles. K will tend to be adsorbed onto the surface of negatively charged soil particles. Potassium uptake is vital for plant growth but in saline soils sodium competes with potassium for uptake across the plasma membrane of plant cells. This can result in high Na+:K+ ratios that reduce plant growth and eventually become toxic. This study aimed to obtain soil transport parameters of potassium in saline soil, such as: pore water velocity in soil (v), retardation factor (R), dispersivity (λ) and dispersion coefficient (D), in a disturbed sandy soil with different concentrations of potassium chlorate solution (KCl), which is one of the most common form of potassium fertilizer. The experiment was carried out using soil samples collected in a depth of 0 to 20 cm, applying potassium chlorate solution containing 28.6, 100, 200 and 500 mg L-1 of K. To obtain transport parameters, the data were adjusted with the software STANMOD. At low concentrations, interaction between potassium and soil occur more efficiently. It was observed that only the breakthrough curve prepared with solution of 500 mg L-1 reached the applied concentration, and the solution of 28.6 mg L-1 overestimated the parameters values. The STANMOD proved to be efficient in obtaining potassium transport parameters; KCl solution to be applied should be greater than 500 mg L-1; solutions with low concentrations tend to overestimate parameters values.

Reduction-melting combined with a Na₂CO₃ flux recycling process for lead recovery from cathode ray tube funnel glass.

PubMed

Okada, Takashi; Yonezawa, Susumu

2014-08-01

With large quantity of flux (Na2CO3), lead can be recovered from the funnel glass of waste cathode-ray tubes via reduction-melting at 1000°C. To reduce flux cost, a technique to recover added flux from the generated oxide phase is also important in order to recycle the flux recovered from the reduction-melting process. In this study, the phase separation of sodium and the crystallization of water-soluble sodium silicates were induced after the reduction-melting process to enhance the leachability of sodium in the oxide phase and to extract the sodium from the phase for the recovery of Na2CO3 as flux. A reductive atmosphere promoted the phase separation and crystallization, and the leachability of sodium from the oxide phase was enhanced. The optimum temperature and treatment time for increasing the leachability were 700°C and 2h, respectively. After treatment, more than 90% of the sodium in the oxide phase was extracted in water. NaHCO3 can be recovered by carbonization of the solution containing sodium ions using carbon dioxide gas, decomposed to Na2CO3 at 50°C and recycled for use in the reduction-melting process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pseudocapacitive Sodium Storage in Mesoporous Single-Crystal-like TiO2-Graphene Nanocomposite Enables High-Performance Sodium-Ion Capacitors.

PubMed

Le, Zaiyuan; Liu, Fang; Nie, Ping; Li, Xinru; Liu, Xiaoyan; Bian, Zhenfeng; Chen, Gen; Wu, Hao Bin; Lu, Yunfeng

2017-03-28

Sodium-ion capacitors can potentially combine the virtues of high power capability of conventional electrochemical capacitors and high energy density of batteries. However, the lack of high-performance electrode materials has been the major challenge of sodium-based energy storage devices. In this work, we report a microwave-assisted synthesis of single-crystal-like anatase TiO 2 mesocages anchored on graphene as a sodium storage material. The architecture of the nanocomposite results in pseudocapacitive charge storage behavior with fast kinetics, high reversibility, and negligible degradation to the micro/nanostructure. The nanocomposite delivers a high capacity of 268 mAh g -1 at 0.2 C, which remains 126 mAh g -1 at 10 C for over 18 000 cycles. Coupling with a carbon-based cathode, a full cell of sodium-ion capacitor successfully demonstrates a high energy density of 64.2 Wh kg -1 at 56.3 W kg -1 and 25.8 Wh kg -1 at 1357 W kg -1 , as well as an ultralong lifespan of 10 000 cycles with over 90% of capacity retention.

METHOD FOR REDUCING THE IMPURITY RESISTIVITY OF SODIUM

DOEpatents

Post, R.F.; Taylor, C.E.

1963-08-13

The inherent resistivity of sodium, at cryogenic temperatures, can be reduced by clustering the impurity atoms within the crystal latiice structure of the sodium, thereby reducing the effective electron collision cross section and thus reducing the number of collisions between the electrons and such lattice imperfections. The clustering is effected by heating the sodium to a temperature approaching its melting point, and maintaining the temperature for a period of time ranging generally from two to six days. (AEC)

Computer-assisted Crystallization.

ERIC Educational Resources Information Center

Semeister, Joseph J., Jr.; Dowden, Edward

1989-01-01

To avoid a tedious task for recording temperature, a computer was used for calculating the heat of crystallization for the compound sodium thiosulfate. Described are the computer-interfacing procedures. Provides pictures of laboratory equipment and typical graphs from experiments. (YP)

Crystallization of Δ1-tetrahydrocannabinolic acid (THCA) synthase from Cannabis sativa

PubMed Central

Shoyama, Yoshinari; Takeuchi, Ayako; Taura, Futoshi; Tamada, Taro; Adachi, Motoyasu; Kuroki, Ryota; Shoyama, Yukihiro; Morimoto, Satoshi

2005-01-01

Δ1-Tetrahydrocannabinolic acid (THCA) synthase is a novel oxidoreductase that catalyzes the biosynthesis of the psychoactive compound THCA in Cannabis sativa (Mexican strain). In order to investigate the structure–function relationship of THCA synthase, this enzyme was overproduced in insect cells, purified and finally crystallized in 0.1 M HEPES buffer pH 7.5 containing 1.4 M sodium citrate. A single crystal suitable for X-ray diffraction measurement was obtained in 0.09 M HEPES buffer pH 7.5 containing 1.26 M sodium citrate. The crystal diffracted to 2.7 Å resolution at beamline BL41XU, SPring-8. The crystal belonged to the primitive cubic space group P432, with unit-cell parameters a = b = c = 178.2 Å. The calculated Matthews coefficient was approximately 4.1 or 2.0 Å3 Da−1 assuming the presence of one or two molecules of THCA synthase in the asymmetric unit, respectively. PMID:16511162

A study of the piezoelectric resonance in metal organic NLO single crystals: Sodium D-isoascorbate monohydrate and Lithium L-ascorbate dihydrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saripalli, Ravi Kiran, E-mail: rksaripalli@physics.iisc.ernet.in; Sanath Kumar, R.; Elizabeth, Suja

2016-05-06

Large single crystals of Sodium D-isoacsorbate monohydrate and Lithium L-ascorbate dehydrate were grown using solution growth technique. Dielectric constant and dielectric loss were monitored as a function of frequency at different temperatures. These are typically characterized by strong resonance peaks. The piezoelectric coefficients d{sub 31}, elastic coefficient (S{sub 11}) and electromechanical coupling coefficient (k{sub 31}) were estimated by resonance-antiresonance method. The temperature dependence of the resonance-peaks frequencies was studied.

Recent achievements on polyanion-type compounds for sodium-ion batteries: Syntheses, crystal chemistry and electrochemical performance

NASA Astrophysics Data System (ADS)

Guo, Sheng-Ping; Li, Jia-Chuang; Xu, Qian-Ting; Ma, Ze; Xue, Huai-Guo

2017-09-01

In the past several years, many efforts have been made to develop polyanion-type cathode materials for sodium ion batteries by chemists and material scientists. These materials are one of the main types of promising cathodes though the studies are still in their infancy. This paper reviews almost all the important advances of polyanion-type cathodes on their syntheses, crystal structures, morphologies, electrochemical performance and Na redox mechanisms. It specifically focuses on their crystal chemistry and electrochemical behaviors. The contents are divided into several categories according to their chemical compositions. After introduction of the synthetic methods, phosphates (ortho-, pyro- and fluoro-), silicates, sulfates, and mixed anions type cathodes are summarized and discussed successively.

Applying the X-ray diffraction analysis for estimating the height and width of nanorods in low symmetry crystal multiphase materials

NASA Astrophysics Data System (ADS)

Mokhtari, Ali; Soleimanian, Vishtasb; Dehkordi, Hamed Aleebrahim; Dastafkan, Kamran

2017-11-01

In this work the potential of Rietveld refinement procedure is used to study the shape and size of non-spherical nanocrystallites. The main advantages of this approach are that not only it can successfully extend to all nanomaterials with different crystal symmetries but also it can evaluate the various phases of multiple materials comparing to electron microscopy methods. Therefore, between seven crystal systems, the formulation of monoclinic and hexagonal crystals is developed. This procedure is applied for the mixture of sodium carbonate and zinc oxide nanocrystallites at different fractions of doped gadolinium oxide. It is found that the crystallites of sodium carbonate and zinc oxide have the rod and ellipsoidal shapes, respectively. The microstructure results are compared with the results of scanning electron microscopy imaging. Good agreement is achieved between the results of scanning electron microscopy and Rietveld methods.

Conformers and hydrogen bonds in cytidine 5‧-diphosphocholine sodium single crystals grown from a mixture of ethanol and water

NASA Astrophysics Data System (ADS)

Du, Zhenxing; Hu, Yanan; Wang, Pei; Zhou, Jingwei; Xiong, Jian; Ying, Hanjie; Bai, Jianxin

2011-01-01

The molecular structure of cytidine 5'-diphosphocholine sodium (CDPC) grown from a mixture of ethanol and water was determined by X-ray diffraction (XRD). CDPC was found to have an orthorhombic structure with confirmed lattice parameters of a = 6.978 Å, b = 12.406 Å and c = 29.326 Å. This nucleotide coenzyme was highly folded and net-like. Each crystallographic unit consisted of one sodium atom, one pyrophosphate group, one cytosine group, one coordinated water molecule, one pentose molecule, and three lattice water molecules. The interspaces of neighboring CDPC molecules were filled with water molecules and methyl groups. Although the coordinated water was connected to sodium atoms, the lattice water molecules formed chair-shaped water hexamers. The hydrogen bonds which played an important role in maintaining the structure included O sbnd H···O, N sbnd H···O and C sbnd H···O and ranged in length from 2.682 (17) to 3.349 (17) Å. Fourier transform infrared spectroscopy (FTIR) showed a broad absorption in the 400-2000 cm -1 region characteristic of short hydrogen bonds. So for industrial crystallization, methods which could eliminate the influence of hydrogen bonds should be taken, and it would be beneficial for the process of crystallization.

Crystallization of Δ{sup 1}-tetrahydrocannabinolic acid (THCA) synthase from Cannabis sativa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shoyama, Yoshinari; Takeuchi, Ayako; Taura, Futoshi

Δ{sup 1}-Tetrahydrocannabinolic acid (THCA) synthase from C. sativa was crystallized. The crystal diffracted to 2.7 Å resolution with sufficient quality for further structure determination. Δ{sup 1}-Tetrahydrocannabinolic acid (THCA) synthase is a novel oxidoreductase that catalyzes the biosynthesis of the psychoactive compound THCA in Cannabis sativa (Mexican strain). In order to investigate the structure–function relationship of THCA synthase, this enzyme was overproduced in insect cells, purified and finally crystallized in 0.1 M HEPES buffer pH 7.5 containing 1.4 M sodium citrate. A single crystal suitable for X-ray diffraction measurement was obtained in 0.09 M HEPES buffer pH 7.5 containing 1.26 Mmore » sodium citrate. The crystal diffracted to 2.7 Å resolution at beamline BL41XU, SPring-8. The crystal belonged to the primitive cubic space group P432, with unit-cell parameters a = b = c = 178.2 Å. The calculated Matthews coefficient was approximately 4.1 or 2.0 Å{sup 3} Da{sup −1} assuming the presence of one or two molecules of THCA synthase in the asymmetric unit, respectively.« less

Chemical conversion of cisplatin and carboplatin with histidine in a model protein crystallized under sodium iodide conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanley, Simon W. M.; Helliwell, John R., E-mail: john.helliwell@manchester.ac.uk

Crystals of HEWL with cisplatin and HEWL with carboplatin grown in sodium iodide conditions both show a partial chemical transformation of cisplatin or carboplatin to a transiodoplatin (PtI{sub 2}X{sub 2}) form. The binding is only at the N{sup δ} atom of His15. A further Pt species (PtI{sub 3}X) is also seen, in both cases bound in a crevice between symmetry-related protein molecules. Cisplatin and carboplatin are platinum anticancer agents that are used to treat a variety of cancers. Previous X-ray crystallographic studies of carboplatin binding to histidine in hen egg-white lysozyme (HEWL) showed a partial chemical conversion of carboplatin tomore » cisplatin owing to the high sodium chloride concentration used in the crystallization conditions. Also, the co-crystallization of HEWL with carboplatin in sodium bromide conditions resulted in the partial conversion of carboplatin to the transbromoplatin form, with a portion of the cyclobutanedicarboxylate (CBDC) moiety still present. The results of the co-crystallization of HEWL with cisplatin or carboplatin in sodium iodide conditions are now reported in order to determine whether the cisplatin and carboplatin converted to the iodo form, and whether this took place in a similar way to the partial conversion of carboplatin to cisplatin in NaCl conditions or to transbromoplatin in NaBr conditions as seen previously. It is reported here that a partial chemical transformation has taken place to a transplatin form for both ligands. The NaI-grown crystals belonged to the monoclinic space group P2{sub 1} with two molecules in the asymmetric unit. The chemically transformed cisplatin and carboplatin bind to both His15 residues, i.e. in each asymmetric unit. The binding is only at the N{sup δ} atom of His15. A third platinum species is also seen in both conditions bound in a crevice between symmetry-related molecules. Here, the platinum is bound to three I atoms identified based on their anomalous difference electron densities and their refined occupancies, with the fourth bound atom being a Cl atom (in the cisplatin case) or a portion of the CBDC moiety (in the carboplatin case)« less

Experiments on Suppression of Thermocapillary Oscillations in Sodium Nitrate Floating Half-Zones by High-frequency End-wall Vibrations

NASA Technical Reports Server (NTRS)

Anilkumar, A.; Grugel, R. N.; Bhowmick, J.; Wang, T.

2004-01-01

Experiments to suppress thermocapillary oscillations using high-frequency vibrations were carried out in sodium nitrate floating half-zones. Such a half-zone is formed by melting one end of a vertically held sodium nitrate crystal rod in contact with a hot surface at the top. Thermocapillary convection occurs in the melt because of the temperature gradient at the free surface of the melt. In the experiments, when thermocapillary oscillations occurred, the bottom end of the crystal rod was vibrated at a high frequency to generate a streaming flow in a direction opposite to that of the thermocapillary convection. It is observed that, by generating a sufficiently strong streaming flow, the thermocapillary flow can be offset enough such that the associated thermocapillary oscillations can be quenched.

Mechanistic Insights into the Allosteric Modulation of Opioid Receptors by Sodium Ions

PubMed Central

2015-01-01

The idea of sodium ions altering G-protein-coupled receptor (GPCR) ligand binding and signaling was first suggested for opioid receptors (ORs) in the 1970s and subsequently extended to other GPCRs. Recently published ultra-high-resolution crystal structures of GPCRs, including that of the δ-OR subtype, have started to shed light on the mechanism underlying sodium control in GPCR signaling by revealing details of the sodium binding site. Whether sodium accesses different receptor subtypes from the extra- or intracellular sides, following similar or different pathways, is still an open question. Earlier experiments in brain homogenates suggested a differential sodium regulation of ligand binding to the three major OR subtypes, in spite of their high degree of sequence similarity. Intrigued by this possibility, we explored the dynamic nature of sodium binding to δ-OR, μ-OR, and κ-OR by means of microsecond-scale, all-atom molecular dynamics (MD) simulations. Rapid sodium permeation was observed exclusively from the extracellular milieu, and following similar binding pathways in all three ligand-free OR systems, notwithstanding extra densities of sodium observed near nonconserved residues of κ-OR and δ-OR, but not in μ-OR. We speculate that these differences may be responsible for the differential increase in antagonist binding affinity of μ-OR by sodium resulting from specific ligand binding experiments in transfected cells. On the other hand, sodium reduced the level of binding of subtype-specific agonists to all OR subtypes. Additional biased and unbiased MD simulations were conducted using the δ-OR ultra-high-resolution crystal structure as a model system to provide a mechanistic explanation for this experimental observation. PMID:25073009

Mechanistic insights into the allosteric modulation of opioid receptors by sodium ions.

PubMed

Shang, Yi; LeRouzic, Valerie; Schneider, Sebastian; Bisignano, Paola; Pasternak, Gavril W; Filizola, Marta

2014-08-12

The idea of sodium ions altering G-protein-coupled receptor (GPCR) ligand binding and signaling was first suggested for opioid receptors (ORs) in the 1970s and subsequently extended to other GPCRs. Recently published ultra-high-resolution crystal structures of GPCRs, including that of the δ-OR subtype, have started to shed light on the mechanism underlying sodium control in GPCR signaling by revealing details of the sodium binding site. Whether sodium accesses different receptor subtypes from the extra- or intracellular sides, following similar or different pathways, is still an open question. Earlier experiments in brain homogenates suggested a differential sodium regulation of ligand binding to the three major OR subtypes, in spite of their high degree of sequence similarity. Intrigued by this possibility, we explored the dynamic nature of sodium binding to δ-OR, μ-OR, and κ-OR by means of microsecond-scale, all-atom molecular dynamics (MD) simulations. Rapid sodium permeation was observed exclusively from the extracellular milieu, and following similar binding pathways in all three ligand-free OR systems, notwithstanding extra densities of sodium observed near nonconserved residues of κ-OR and δ-OR, but not in μ-OR. We speculate that these differences may be responsible for the differential increase in antagonist binding affinity of μ-OR by sodium resulting from specific ligand binding experiments in transfected cells. On the other hand, sodium reduced the level of binding of subtype-specific agonists to all OR subtypes. Additional biased and unbiased MD simulations were conducted using the δ-OR ultra-high-resolution crystal structure as a model system to provide a mechanistic explanation for this experimental observation.

Crystallization of a 2:2 complex of granulocyte-colony stimulating factor (GCSF) with the ligand-binding region of the GCSF receptor

PubMed Central

Honjo, Eijiro; Tamada, Taro; Maeda, Yoshitake; Koshiba, Takumi; Matsukura, Yasuko; Okamoto, Tomoyuki; Ishibashi, Matsujiro; Tokunaga, Masao; Kuroki, Ryota

2005-01-01

The granulocyte-colony stimulating factor (GCSF) receptor receives signals for regulating the maturation, proliferation and differentiation of the precursor cells of neutrophilic granulocytes. The signalling complex composed of two GCSFs (GCSF, 19 kDa) and two GCSF receptors (GCSFR, 34 kDa) consisting of an Ig-like domain and a cytokine-receptor homologous (CRH) domain was crystallized. A crystal of the complex was grown in 1.0 M sodium formate and 0.1 M sodium acetate pH 4.6 and belongs to space group P41212 (or its enantiomorph P43212), with unit-cell parameters a = b = 110.1, c = 331.8 Å. Unfortunately, this crystal form did not diffract beyond 5 Å resolution. Since the heterogeneity of GCSF receptor appeared to prevent the growth of good-quality crystals, the GCSF receptor was fractionated by anion-exchange chromatography. Crystals of the GCSF–fractionated GCSF receptor complex were grown as a new crystal form in 0.2 M ammonium phosphate. This new crystal form diffracted to beyond 3.0 Å resolution and belonged to space group P3121 (or its enantiomorph P3221), with unit-cell parameters a = b = 134.8, c = 105.7 Å. PMID:16511159

Effects of ammonium sulfate and sodium chloride concentration on PEG/protein liquid-liquid phase separation.

PubMed

Dumetz, André C; Lewus, Rachael A; Lenhoff, Abraham M; Kaler, Eric W

2008-09-16

When added to protein solutions, poly(ethylene glycol) (PEG) creates an effective attraction between protein molecules due to depletion forces. This effect has been widely used to crystallize proteins, and PEG is among the most successful crystallization agents in current use. However, PEG is almost always used in combination with a salt at either low or relatively high concentrations. Here the effects of sodium chloride and ammonium sulfate concentration on PEG 8000/ovalbumin liquid-liquid (L-L) phase separation are investigated. At low salt the L-L phase separation occurs at decreasing protein concentration with increasing salt concentration, presumably due to repulsive electrostatic interactions between proteins. At high salt concentration, the behavior depends on the nature of the salt. Sodium chloride has little effect on the L-L phase separation, but ammonium sulfate decreases the protein concentration at which the L-L phase separation occurs. This trend is attributed to the effects of critical fluctuations on depletion forces. The implications of these results for designing solution conditions optimal for protein crystallization are discussed.

View of Sodium Chloride inserted onto blueberry jelly within a metal loop on Expedition Six

NASA Image and Video Library

2003-03-15

ISS006-E-39282 (15 March 2003) --- A view of sodium chloride inserted onto blueberry jelly within a 50-millimeter (mm) metal loop was photographed by an Expedition Six crewmember. The water in the sodium chloride solution evaporates as it leaves larger three-dimensional crystals while the blueberry jelly hardens. The experiment took place in the Destiny laboratory on the International Space Station (ISS).

The discrimination of 72 nitrate, chlorate and perchlorate salts using IR and Raman spectroscopy

NASA Astrophysics Data System (ADS)

Zapata, Félix; García-Ruiz, Carmen

2018-01-01

Inorganic oxidizing energetic salts including nitrates, chlorates and perchlorates are widely used in the manufacture of not only licit pyrotechnic compositions, but also illicit homemade explosive mixtures. Their identification in forensic laboratories is usually accomplished by either capillary electrophoresis or ion chromatography, with the disadvantage of dissociating the salt into its ions. On the contrary, vibrational spectroscopy, including IR and Raman, enables the non-invasive identification of the salt, i.e. avoiding its dissociation. This study focuses on the discrimination of all nitrate, chlorate and perchlorate salts that are commercially available, using both Raman and IR spectroscopy, with the aim of testing whether every salt can be unequivocally identified. Besides the visual spectra comparison by assigning every band with the corresponding molecular vibrational mode, a statistical analysis based on Pearson correlation was performed to ensure an objective identification, either using Raman, IR or both. Positively, 25 salts (out of 72) were unequivocally identified using Raman, 30 salts when using IR and 44 when combining both techniques. Negatively, some salts were undistinguishable even using both techniques demonstrating there are some salts that provide very similar Raman and IR spectra.

Ionic Fluorine Chemistry.

DTIC Science & Technology

SOLID ROCKET OXIDIZERS, *LIQUID ROCKET OXIDIZERS, CHLORATES, FLUORIDES, ACETONES, CHLORINE COMPOUNDS, NITROSO COMPOUNDS, *HALOGEN COMPOUNDS, ADDITION REACTIONS, CESIUM COMPOUNDS, CHLORIDES, COMPLEX COMPOUNDS

Sodium sulfate crystallisation monitoring using IR thermography

NASA Astrophysics Data System (ADS)

Vazquez, P.; Thomachot-Schneider, C.; Mouhoubi, K.; Bodnar, J.-L.; Avdelidis, N. P.; Charles, D.; Benavente, D.

2018-03-01

In this work, the evaporation of sodium sulfate droplets with different concentrations and at different temperatures were studied using infrared thermography (IRT). IRT allows to detect the evaporation evolution, the crystal growth and for the first time, to observe in vivo the heat release related to sodium sulfate crystallisation. A detailed study revealed that dendritic Thenardite III crystals appeared at the edge of all the crystallised droplets, though they showed a fast increase of temperature related to crystallisation only when a hydrated phase crystallised also from the droplet. The observation of the heat of crystallisation is thus directly related to the supersaturation of the droplet and consequently to temperature. In addition, IRT detection is circumscribed by the location of crystallisation. The heat can be observed and measured only when the crystallisation occurs in the interface solution - air.

Sodium Chloride Crystal-Induced SERS Platform for Controlled Highly Sensitive Detection of Illicit Drugs.

PubMed

Yu, Borong; Li, Pan; Zhou, Binbin; Tang, Xianghu; Li, Shaofei; Yang, Liangbao

2018-04-03

A sodium chloride crystal-driven spontaneous 'hot spot' structure was demonstrated as a SERS-active platform, to get reproducible SERS signals, and eliminate the need for mapping large areas, in comparison with solution phase testing. During the process of solvent evaporation, the crystals produced induced silver aggregates to assemble around themselves. The micro-scale crystals can also act as a template to obtain an optical position, such that the assembled hot area is conveniently located during SERS measurements. More importantly, the chloride ions added in colloids can also replace the citrate and on the surface of the silver sol, and further decrease the background interference. High quality SERS spectra from heroin, methamphetamine (MAMP), and cocaine have been obtained on the crystal-driven hot spot structure with high sensitivity and credible reproducibility. This approach can not only bring the nanoparticles to form plasmonic hot spots in a controlled way, and thus provide high sensitivity, but also potentially be explored as an active substrate for label-free detection of other illicit drugs or additives. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pretreatment of Hanford medium-curie wastes by fractional crystallization.

PubMed

Nassif, Laurent; Dumont, George; Alysouri, Hatem; Rousseau, Ronald W

2008-07-01

Acceleration of the schedule for decontamination of the Hanford site using bulk vitrification requires implementation of a pretreatment operation. Medium-curie waste must be separated into two fractions: one is to go to a waste treatment and immobilization plant and a second, which is low-activity waste, is to be processed by bulk vitrification. The work described here reports research on using fractional crystallization for that pretreatment. Sodium salts are crystallized by evaporation of water from solutions simulating those removed from single-shell tanks, while leaving cesium in solution. The crystalline products are then recovered and qualified as low-activity waste, which is suitable upon redissolution for processing by bulk vitrification. The experimental program used semibatch operation in which a feed solution was continuously added to maintain a constant level in the crystallizer while evaporating water. The slurry recovered at the end of a run was filtered to recover product crystals, which were then analyzed to determine their composition. The results demonstrated that targets on cesium separation from the solids, fractional recovery of sodium salts, and sulfate content of the recovered salts can be achieved by the process tested.

Synthesis, crystal structures and Hirshfeld surface analyses of two new Salen type nickel/sodium heteronuclear complexes

NASA Astrophysics Data System (ADS)

Mahlooji, Niloofar; Behzad, Mahdi; Tarahhomi, Atekeh; Maroney, Michael; Rudbari, Hadi Amiri; Bruno, Giuseppe; Ghanbari, Bahram

2016-04-01

Two new heteronuclear Nickel(II)/Sodium(I) complexes of a side-off compartmental Schiff base ligand were synthesized and characterized by spectroscopic methods. Crystal structures of both of the complexes were also obtained. The Schiff base ligand was synthesized from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with 2-hydroxy-3-methoxybenzaldehyde. In both of the complexes the Ni(II) ion is coordinated to the inner N2O2 coordination sphere with square-planar geometry and the Na(I) ion is coordinated to the outer O2 O2‧ coordination sphere. In Complex (1) with general formula [Ni(L)Na(CH3OH)(ClO4)] the sodium ion is seven coordinated while in (2) with general formula [{Ni(L)Na(OH2)}2(μ-Ni(CN)4)] the sodium ion is six coordinated. Intermolecular interactions in two studied complexes were analyzed using 3D Hirshfeld surfaces and corresponding 2D fingerprint plots. This analysis showed that the H … H and C … H/H … C contacts for both structures (altogether 67.5% of total Hirshfeld surface area for (1) and 77.6% for (2)) and the O … H/H … O (24.2%) for (1) and the N … H/H … N (8.1%) contacts for (2) were the characteristic intermolecular contacts in the related crystal structures.

Growth and characterization of struvite-Na crystals

NASA Astrophysics Data System (ADS)

Chauhan, Chetan K.; Joshi, Mihirkumar J.

2014-09-01

Sodium magnesium phosphate heptahydrate [NaMgPO4·7H2O], also known as struvite-Na, is the sodium analog to struvite. Among phosphate containing bio-minerals, struvite has attracted considerable attention, because of its common occurrence in a wide variety of environments. Struvite and family crystals were found as urinary calculi in humans and animals. Struvite-Na crystals were grown by a single diffusion gel growth technique in a silica hydro gel medium. Struvite-Na crystals with different morphologies having transparent to translucent diaphaneity were grown with different growth parameters. The phenomenon of Liesegang rings was also observed with some particular growth parameters. The powder XRD study confirmed the structural similarity of the grown struvite-Na crystals with struvite and found that struvite-Na crystallized in the orthorhombic Pmn21 space group with unit cell parameters such as a= 6.893 Å, b=6.124 Å, c=11.150 Å, and α=β=γ=90°. FT-IR spectra of struvite-Na crystals revealed the presence of functional groups. The TGA, DTA and DSC were carried out simultaneously. The kinetic and thermodynamic parameters of dehydration/decomposition process were calculated. The variation of dielectric constant with frequency of applied field was studied in the range from 400 Hz to 100 kHz.

Impact of surfactants on the crystallization of aqueous suspensions of celecoxib amorphous solid dispersion spray dried particles.

PubMed

Chen, Jie; Ormes, James D; Higgins, John D; Taylor, Lynne S

2015-02-02

Amorphous solid dispersions are frequently prepared by spray drying. It is important that the resultant spray dried particles do not crystallize during formulation, storage, and upon administration. The goal of the current study was to evaluate the impact of surfactants on the crystallization of celecoxib amorphous solid dispersions (ASD), suspended in aqueous media. Solid dispersions of celecoxib with hydroxypropylmethylcellulose acetate succinate were manufactured by spray drying, and aqueous suspensions were prepared by adding the particles to acidified media containing various surfactants. Nucleation induction times were evaluated for celecoxib in the presence and absence of surfactants. The impact of the surfactants on drug and polymer leaching from the solid dispersion particles was also evaluated. Sodium dodecyl sulfate and Polysorbate 80 were found to promote crystallization from the ASD suspensions, while other surfactants including sodium taurocholate and Triton X100 were found to inhibit crystallization. The promotion or inhibition of crystallization was found to be related to the impact of the surfactant on the nucleation behavior of celecoxib, as well as the tendency to promote leaching of the drug from the ASD particle into the suspending medium. It was concluded that surfactant choice is critical to avoid failure of amorphous solid dispersions through crystallization of the drug.

In situ observation on the dynamic process of evaporation and crystallization of sodium nitrate droplets on a ZnSe substrate by FTIR-ATR.

PubMed

Zhang, Qing-Nuan; Zhang, Yun; Cai, Chen; Guo, Yu-Cong; Reid, Jonathan P; Zhang, Yun-Hong

2014-04-17

Sodium nitrate is a main component of aging sea salt aerosol, and its phase behavior has been studied repeatedly with wide ranges observed in the efflorescence relative humidity (RH) in particular. Studies of the efflorescence dynamics of NaNO3 droplets deposited on a ZnSe substrate are reported, using an in situ Fourier transform infrared attenuated total reflection (FTIR-ATR) technique. The time-dependence of the infrared spectra of NaNO3 aerosols accompanying step changes in RH have been measured with high signal-to-noise ratio. From the IR difference spectra recorded, changes of the time-dependent absorption peak area of the O-H stretching band (ν-OH, ∼3400 cm(-1)) and the nitrate out-of-plane bending band (ν2-NO3(-), ∼836 cm(-1)) are obtained. From these measurements, changes in the IR signatures can be attributed to crystalline and solution phase nitrate ions, allowing the volume fraction of the solution droplets that have crystallized to be determined. Then, using these clear signatures of the volume fraction of droplets that have yet to crystallize, the homogeneous and heterogeneous nucleation kinetics can be studied from conventional measurements using a steady decline in RH. The nucleation rate measurements confirm that the rate of crystallization in sodium nitrate droplets is considerably less than in ammonium sulfate droplets at any particular degree of solute supersaturation, explaining the wide range of efflorescence RHs observed for sodium nitrate in previous studies. We demonstrate that studying nucleation kinetics using the FTIR-ATR approach has many advantages over brightfield imaging studies on smaller numbers of larger droplets or measurements made on single levitated particles.

Crystallization and preliminary X-ray analysis of membrane-bound pyrophosphatases.

PubMed

Kellosalo, Juho; Kajander, Tommi; Honkanen, Riina; Goldman, Adrian

2013-02-01

Membrane-bound pyrophosphatases (M-PPases) are enzymes that enhance the survival of plants, protozoans and prokaryotes in energy constraining stress conditions. These proteins use pyrophosphate, a waste product of cellular metabolism, as an energy source for sodium or proton pumping. To study the structure and function of these enzymes we have crystallized two membrane-bound pyrophosphatases recombinantly produced in Saccharomyces cerevisae: the sodium pumping enzyme of Thermotoga maritima (TmPPase) and the proton pumping enzyme of Pyrobaculum aerophilum (PaPPase). Extensive crystal optimization has allowed us to grow crystals of TmPPase that diffract to a resolution of 2.6 Å. The decisive step in this optimization was in-column detergent exchange during the two-step purification procedure. Dodecyl maltoside was used for high temperature solubilization of TmPPase and then exchanged to a series of different detergents. After extensive screening, the new detergent, octyl glucose neopentyl glycol, was found to be the optimal for TmPPase but not PaPPase.

Co-doped sodium chloride crystals exposed to different irradiation temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz-Morales, A.; Cruz-Zaragoza, E.; Furetta, C.

2013-07-03

Monocrystals of NaCl:XCl{sub 2}:MnCl{sub 2}(X = Ca,Cd) at four different concentrations have been analyzed. The crystals were exposed to different irradiation temperature, such as at room temperature (RT), solid water (SW), dry ice (DI) and liquid nitrogen (LN). The samples were irradiated with photon from {sup 60}Co irradiators. The co-doped sodium chloride crystals show a complex structure of glow curves that can be related to different distribution of traps. The linearity response was analyzed with the F(D) index. The F(D) value was less than unity indicating a sub-linear response was obtained from the TL response on the function of themore » dose. The glow curves were deconvoluted by using the CGCD program based on the first, second and general order kinetics.« less

Catalytic Biomineralization of Fluorescent Calcite by the Thermophilic Bacterium Geobacillus thermoglucosidasius▿

PubMed Central

Yoshida, Naoto; Higashimura, Eiji; Saeki, Yuichi

2010-01-01

The thermophilic Geobacillus bacterium catalyzed the formation of 100-μm hexagonal crystals at 60°C in a hydrogel containing sodium acetate, calcium chloride, and magnesium sulfate. Under fluorescence microscopy, crystals fluoresced upon excitation at 365 ± 5, 480 ± 20, or 545 ± 15 nm. X-ray diffraction indicated that the crystals were magnesium-calcite in calcite-type calcium carbonate. PMID:20851984

Control of Sulfidogenesis Through Bio-oxidation of H 2S Coupled to (per)chlorate Reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregoire, Patrick; Engelbrektson, Anna; Hubbard, Christopher G.

2014-04-04

Here, we investigate H 2S attenuation by dissimilatory perchlorate-reducing bacteria (DPRB). All DPRB tested oxidized H 2S coupled to (per)chlorate reduction without sustaining growth. H 2S 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 H 2S 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.

Crystallization of calcium oxalate in minimally diluted urine

NASA Astrophysics Data System (ADS)

Bretherton, T.; Rodgers, A.

1998-09-01

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

Lyotropic liquid crystal behaviour of azelate and succinate monoester surfactants based on fragrance alcohols.

PubMed

Marchal, Frédéric; Nardello-Rataj, Véronique; Chailloux, Nelly; Aubry, Jean-Marie; Tiddy, Gordon J T

2008-05-01

Azelaic acid was used as a starting material for the preparation of new monoester surfactants based on fragrance alcohols. Sodium monocitronellyl azelate (citroC(9)Na) and sodium monomenthyl azelate (menC(9)Na) were synthesized and their aqueous phase behaviour was studied. For comparison, monoesters derived from succinic anhydride, i.e. sodium monocitronellyl succinate (citroC(4)Na) and sodium monomenthyl succinate (menC(4)Na), were also prepared as well as sodium monodecyl succinate (C(10)C(4)Na) and sodium monodecyl azelate (C(10)C(9)Na) in order to study the effect of the position of the ester function inside the hydrophobic tail and of branching and unsaturation respectively. Liquid crystal structures were examined by optical polarising microscopy and schematic partial binary phase diagrams (surfactant+water, 0-100 wt%, 10-90 degrees C) of the surfactants were established. Succinate surfactants behave as longer alkyl chain surfactants than their azelate counterparts, meaning that these last ones probably adopt a more folded conformation, with the ester function more frequently present at the micelle surface. This conformation would result in a rougher micelle surface, making it slightly less easy for micelles to pack in liquid crystalline phases. It was also shown that the tendency to adopt a more folded conformation and to form smaller micelles is ranked in this order: monomenthyl>monocitronellyl>monodecyl.

Structural Stability and Electronic Properties of Na2C6O6 for a Rechargeable Sodium-ion Battery

NASA Astrophysics Data System (ADS)

Yamashita, Tomoki; Fujii, Akihiro; Momida, Hiroyoshi; Oguchi, Tamio

2014-03-01

Sodium-ion batteries have been explored as a promising alternative to lithium-ion batteries owing to a significant advantage of a natural abundance of sodium. Recently, it has been reported that disodium rhodizonate, Na2C6O6, exhibit good electrochemical properties and cycle performance as a minor-metal free organic cathode for sodium-ion batteries. However, its crystal structures during discharge/charge cycle still remain unclear. In this work, we theoretically propose feasible crystal structures of Na2+xC6O6 using first principles calculations. A structural phase transition has been found: Na4C6O6 has a different C6O6 packing arrangement from Na2C6O6. Electronic structures of Na2+xC6O6 during discharge/charge cycle are also discussed. Our predictions could be the key to understanding the discharge/charge process of Na2C6O6. Supported by MEXT program ``Elements Strategy Initiative to Form Core Rersearch Center'' (since 2012), MEXT; Ministry of Education Culture, Sports, Science and Technology, Japan.

Spectral Behavior of Irradiated Sodium Chloride Crystals Under Europa-Like Conditions

NASA Astrophysics Data System (ADS)

Poston, Michael J.; Carlson, Robert W.; Hand, Kevin P.

2017-12-01

F- and M-color center formation (decay) was observed during (after) irradiation of sodium chloride crystal grains with 10 keV electrons as a function of temperature, radiation dose rate, and radiation dose. The F centers (peak center: 460 nm) were found to form and decay at a faster rate than the M centers (peak center: 720 nm). These effects were influenced by temperature and possibly by irradiation dose rate. Tracking the band depth ratio of the color center features during irradiation could enable age determination of geologically very young features on the surface of Europa and other icy ocean worlds.

The sorption of silver by poorly crystallized manganese oxides

USGS Publications Warehouse

Anderson, B.J.; Jenne, E.A.; Chao, T.T.

1973-01-01

The sorption of silver by poorly crystallized manganese oxides was studied using synthesized samples of three members of the manganous manganite (birnessite) group, of different chemical composition and crystallinity, and a poorly organized ??-MnO2. All four oxides sorbed significant quantities of silver. The manganous manganites showed the greatest sorption (up to 0.5 moles silver/mole MnOx at pH 7) while the ??-MnO2 showed the least (0.3 moles silver/ mole MnOx at pH 7). Sorption of silver was adequately described by the Langmuir equation over a considerable concentration range. The relationship failed at low pH values and high equilibrium silver concentrations. The sorption capacity showed a direct relationship with pH. However, the rate of increase of sorption capacity decreased at the higher pH values. Silver sorption maxima. were not directly related to surface area but appeared to vary with the amount of occluded sodium and potassium present in the manganese oxide. The important processes involved in the uptake of silver by the four poorly crystallized manganese oxides ara considered to be surface exchange for manganese, potassium and sodium as well as exchange for structural manganese, potassium and sodium. ?? 1973.

A solid state tunable laser for resonance measurements of atmospheric sodium

NASA Technical Reports Server (NTRS)

Philbrick, C. R.; Bufton, J. L.; Gardner, C. S.

1985-01-01

The measurement of wave dynamics in the upper mesosphere using a solid-state laser to excite the resonance fluorescence line of sodium is examined. Two Nd:YAG lasers are employed to produce the sodium resonance line. The method involves mixing the 1064 nm radiation with that from a second Nd:YAG operating at 1319 nm in a nonlinear infrared crystal to directly produce 589 nm radiation by sum frequency generation. The use of the transmitter to measure the sodium layer from the Space Shuttle Platform is proposed. A diagram of the laser transmitter is presented.

Thermal decomposition and isomerization of cis-permethrin and beta-cypermethrin in the solid phase.

PubMed

González Audino, Paola; Licastro, Susana A; Zerba, Eduardo

2002-02-01

The stability to heart of cis-permethrin and beta-cypermethrin in the solid phase was studied and the decomposition products identified. Samples heated at 210 degrees C in an oven in the dark showed that, in the absence of potassium chlorate (the salt present in smoke-generating formulations of these pyrethroids), cis-permethrin was not isomerized, although in the presence of that salt, decomposition was greater and thermal isomerization occurred. Other salts of the type KXO3 or NaXO3, with X being halogen or nitrogen, also led to a considerable thermal isomerization. Heating the insecticides in solution in the presence of potassium chlorate did not produce isomerization in any of the solvents assayed. Salt-catalysed thermal cis-trans isomerization was also found for other pyrethroids derived from permethrinic or deltamethrinic acid but not for those derived from chrysanthemic acid. The main thermal degradation processes of cis-permethrin and beta-cypermethrin decomposition when potassium chlorate was present were cyclopropane isomerization, ester cleavage and subsequent oxidation of the resulting products. Permethrinic acid, 3-phenoxybenzyle chloride, alcohol, aldehyde and acid were identified in both cases, as well as 3-phenoxybenzyl cyanide from beta-cypermethrin. A similar decomposition pattern occurred after combustion of pyrethroid fumigant formulations.

Disinfection aboard cruise liners and naval units: formation of disinfection by-products using chlorine dioxide in different qualities of drinking water.

PubMed

Ufermann, Petra; Petersen, Hauke; Exner, Martin

2011-12-01

The world-wide deployment of cruise liners and naval units has caused an increased need for the disinfection of drinking water. The main cause for this is the unknown quality of drinking water in foreign harbours--besides the formation of bio-films due to the climatically disadvantageous conditions in the operational area. Water conduits on board are currently disinfected with calcium hypochlorite in case of microbiological contamination. Chemical and physical analyses after disinfection with calcium hypochlorite have shown that organic by-products consisting of trihalomethanes develop in considerable amounts during disinfection. Furthermore, the method is susceptible to handling errors and thus often leads to insufficient disinfection results. Hitherto, the use of other disinfection methods allowed by government regulations, especially chlorine dioxide, is not widely spread. Unlike disinfection with calcium hypochlorite, chlorine dioxide does not lead to the formation of trihalomethanes. Typical disinfection by-products (DBP) are the anions chlorite and chlorate, which are formed in oxidative processes. The formation conditions of these anions have not yet been elucidated. For this reason, the probability of the generation of inorganic by-products after disinfection with chlorine dioxide has been determined, and their occurrence in drinking water on board has been examined with respect to a possible correlation between water quality and the formation of chlorate and chlorite. Therefore, a chromatographic method was developed and validated in order to determine the periodical development of chlorate and chlorite from chorine dioxide in purified water at different pH-values as well as in actual drinking water samples from water conduits on board. The formation of the by-products chlorite and chlorate after disinfection with chlorine dioxide is influenced neither by pH-value nor by chemical properties of the disinfected water. Considering the examined conditions, chlorine dioxide is suitable for usage on board due to its simple handling and the low potential of producing by-products. Copyright © 2011 Elsevier GmbH. All rights reserved.

On the role of convective motion during dendrite growth: Experiments under variable gravity, revised

NASA Technical Reports Server (NTRS)

Hallett, J.; Cho, N.; Harrison, K.; Lord, A.; Wedum, E.; Purcell, R.; Saunders, C. P. R.

1987-01-01

Experiments show the effect of self induced convection on individual dendrite growth in uniformly supercooled samples and solidification of the resulting mush under conditions of high and low g. Convection is visualized by a Schlieren optical system or a Mach Zender interferometer. For ice crystals growing from the vapor in air, a slight reduction in linear growth rate occur under low g. For ice crystals growing from NaCl solution, dendrite tip velocities are unchanged, but subsequent mush solidification is enhanced through drainage channels under higher g. By contrast, sodium sulfate decahydrate dendrites growing from solution produce convective plumes which lead to higher tip growth rate only as the crystal growth direction approaches that of gravity. Convective plumes are laminar for small crystals under conditions of these experiments; the rise velocity of such plumes is greater than individual vortex rings under identical conditions. Convection effects are only present in solution under a critical supercooling less than about 5 C for sodium sulfate and 2 C for ice in NaCl since at higher supercooling the crystallization velocity, proportional to the square of the supercooling, exceeds the convective velocity, proportional to the square root of the supercooling. The role of convective velocity in bulk solidification is to give a large scale flow which under extreme cases may lead to extensive secondary crystal production, which alters the resulting crystal texture of the completely solidified melt.

Overexpression, crystallization and preliminary X-ray crystallographic analysis of phosphopantetheine adenylyltransferase from Enterococcus faecalis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Ji Yong; Lee, Hyung Ho; Yoon, Hye Jin

2006-11-01

Phosphopantetheine adenylyltransferase from En. faecalis was crystallized and X-ray diffraction data were collected to 2.70 Å resolution. Phosphopantetheine adenylyltransferase, an essential enzyme in the coenzyme A biosynthetic pathway, catalyzes the reversible transfer of an adenylyl group from ATP to 4′-phosphopantetheine, yielding 3′-dephospho-CoA and pyrophosphate. Enterococcus faecalis PPAT has been overexpressed in Escherichia coli as a fusion with a C-terminal purification tag and crystallized at 297 K using a reservoir solution consisting of 0.1 M sodium HEPES pH 7.5, 0.8 M sodium dihydrogen phosphate and 0.8 M potassium dihydrogen phosphate. X-ray diffraction data were collected to 2.70 Å at 100 K.more » The crystals belong to the primitive tetragonal space group P4{sub 1} (or P4{sub 3}), with unit-cell parameters a = b = 160.81, c = 225.68 Å. Four copies of the hexameric molecule are likely to be present in the asymmetric unit, giving a crystal volume per protein weight (V{sub M}) of 3.08 Å{sup 3} Da{sup −1} and a solvent content of 60.1%.« less

The purification, crystallization and preliminary diffraction of a glycerophosphodiesterase from Enterobacter aerogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Colin J.; Carr, Paul D.; Kim, Hye-Kyung

2006-07-01

The metallo-glycerophosphodiesterase from E. aerogenes (GpdQ) has been cloned, expressed in E. coli and purified. Initial screening of crystallization conditions for this enzyme resulted in the identification of needles from one condition in a sodium malonate grid screen. Removal of the metals from the enzyme and subsequent optimization of these conditions led to crystals. The metallo-glycerophosphodiesterase from Enterobacter aerogenes (GpdQ) has been cloned, expressed in Escherichia coli and purified. Initial screening of crystallization conditions for this enzyme resulted in the identification of needles from one condition in a sodium malonate grid screen. Removal of the metals from the enzyme andmore » subsequent optimization of these conditions led to crystals that diffracted to 2.9 Å and belonged to space group P2{sub 1}3, with unit-cell parameter a = 164.1 Å. Self-rotation function analysis and V{sub M} calculations indicated that the asymmetric unit contains two copies of the monomeric enzyme, corresponding to a solvent content of 79%. It is intended to determine the structure of this protein utilizing SAD phasing from transition metals or molecular replacement.« less

Refinements to the structure of graphite oxide: absolute quantification of functional groups via selective labelling

NASA Astrophysics Data System (ADS)

Eng, Alex Yong Sheng; Chua, Chun Kiang; Pumera, Martin

2015-11-01

Chemical modification and functionalization of inherent functional groups within graphite oxide (GO) are essential aspects of graphene-based nano-materials used in wide-ranging applications. Despite extensive research, there remains some discrepancy in its structure, with current knowledge limited primarily to spectroscopic data from XPS, NMR and vibrational spectroscopies. We report herein an innovative electrochemistry-based approach. Four electroactive labels are chosen to selectively functionalize groups in GO, and quantification of each group is achieved by voltammetric analysis. This allows for the first time quantification of absolute amounts of each group, with a further advantage of distinguishing various carbonyl species: namely ortho- and para-quinones from aliphatic ketones. Intrinsic variations in the compositions of permanganate versus chlorate-oxidized GOs were thus observed. Principal differences include permanganate-GO exhibiting substantial quinonyl content, in comparison to chlorate-GO with the vast majority of its carbonyls as isolated ketones. The results confirm that carboxylic groups are rare in actuality, and are in fact entirely absent from chlorate-GO. These observations refine and advance our understanding of GO structure by addressing certain disparities in past models resulting from employment of different oxidation routes, with the vital implication that GO production methods cannot be used interchangeably in the manufacture of graphene-based devices.Chemical modification and functionalization of inherent functional groups within graphite oxide (GO) are essential aspects of graphene-based nano-materials used in wide-ranging applications. Despite extensive research, there remains some discrepancy in its structure, with current knowledge limited primarily to spectroscopic data from XPS, NMR and vibrational spectroscopies. We report herein an innovative electrochemistry-based approach. Four electroactive labels are chosen to selectively functionalize groups in GO, and quantification of each group is achieved by voltammetric analysis. This allows for the first time quantification of absolute amounts of each group, with a further advantage of distinguishing various carbonyl species: namely ortho- and para-quinones from aliphatic ketones. Intrinsic variations in the compositions of permanganate versus chlorate-oxidized GOs were thus observed. Principal differences include permanganate-GO exhibiting substantial quinonyl content, in comparison to chlorate-GO with the vast majority of its carbonyls as isolated ketones. The results confirm that carboxylic groups are rare in actuality, and are in fact entirely absent from chlorate-GO. These observations refine and advance our understanding of GO structure by addressing certain disparities in past models resulting from employment of different oxidation routes, with the vital implication that GO production methods cannot be used interchangeably in the manufacture of graphene-based devices. Electronic supplementary information (ESI) available: Voltammograms of labelled GO at acidic vs. neutral pH; control experiment investigating effects of non-specific adsorption; X-ray photoelectron spectra and Fourier transform infrared spectra of GOs after functionalization and their corresponding controls; Coulombic charges passed from electrochemical redox of labels; detailed calculation of epoxyl content in GO; inherent electrochemistry of GOs; physical images of functionalized and control GOs. See DOI: 10.1039/c5nr05891k

Layered double hydroxide using hydrothermal treatment: morphology evolution, intercalation and release kinetics of diclofenac sodium

NASA Astrophysics Data System (ADS)

Joy, Mathew; Iyengar, Srividhya J.; Chakraborty, Jui; Ghosh, Swapankumar

2017-12-01

The present work demonstrates the possibilities of hydrothermal transformation of Zn-Al layered double hydroxide (LDH) nanostructure by varying the synthetic conditions. The manipulation in washing step before hydrothermal treatment allows control over crystal morphologies, size and stability of their aqueous solutions. We examined the crystal growth process in the presence and the absence of extra ions during hydrothermal treatment and its dependence on the drug (diclofenac sodium (Dic-Na)) loading and release processes. Hexagonal plate-like crystals show sustained release with ˜90% of the drug from the matrix in a week, suggesting the applicability of LDH nanohybrids in sustained drug delivery systems. The fits to the release kinetics data indicated the drug release as a diffusion-controlled release process. LDH with rod-like morphology shows excellent colloidal stability in aqueous suspension, as studied by photon correlation spectroscopy.

EPR study of gamma irradiated N-methyl taurine (C3H9NO3S) and sodium hydrogen sulphate monohydrate (NaHSO3·H2O) single crystals.

PubMed

Yıldırım, Ilkay; Karabulut, Bünyamin

2011-03-01

EPR study of gamma irradiated C(3)H(9)NO(3)S and NaHSO(3).H(2)O single crystals have been carried out at room temperature. There is one site for the radicals in C(3)H(9)NO(3)S and two magnetically distinct sites for the radicals in NaHSO(3). The observed lines in the EPR spectra have been attributed to the species of SO(3)(-) and RH radicals for N-methyl taurine, and to the SO(3)(-) and OH radicals for sodium hydrogen sulfate monohydrate single crystals. The principal values of the g for SO(3)(-), the hyperfine values of RH and OH proton splitting have been calculated and discussed. Copyright © 2010 Elsevier B.V. All rights reserved.

Perchlorate and iodide in whole blood samples from infants, children, and adults in Nanchang, China.

PubMed

Zhang, Tao; Wu, Qian; Sun, Hong Wen; Rao, Jia; Kannan, Kurunthachalam

2010-09-15

Perchlorate, ClO(4)(-), interferes with iodide (I(-)) uptake by the sodium-iodide symporter (NIS) and thereby affects thyroid hormone production in the body. Studies have reported human exposures to perchlorate based on measurements in urine, but little is known about the levels in blood. In this study, we determined concentrations of perchlorate, iodide, and other anions (e.g., chlorate [ClO(3)(-)], bromate [BrO(3)(-)], bromide [Br(-)]) in 131 whole blood samples collected from Chinese donors aged 0.4 to 90 yr, in Nanchang, China. Perchlorate, iodide, and bromide were detected in all of the samples analyzed, whereas chlorate was found in only 27% of the samples and bromate was found in only 2%. The mean (range) concentrations of perchlorate, iodide, and bromide were 2.68 (0.51-10.5), 42.6 (1.58-812), and 2120 (1050-4850) ng/mL, respectively. Perchlorate levels in blood from Nanchang adults were 10-fold greater than levels that have been previously reported for U.S. adults. The iodide/perchlorate molar ratio ranged from 3.05 to 15.3 for all age groups, and the ratio increased with age (r = 0.732, p < 0.01). Perchlorate and bromide concentrations decreased significantly with age, whereas iodide concentrations increased with age. No significant gender-related differences in blood perchlorate, iodide, or bromide levels were found. A significant negative correlation was found between the concentrations of perchlorate and iodide in blood. Exposure doses of perchlorate were estimated for infants, toddlers, children, adolescents, and adults based on the measured concentrations in blood, using a simple pharmacokinetic model. The mean exposure doses of perchlorate for our age groups ranged from 1.12 (adults) to 2.22 μg/kg bw/day (infants), values higher than the United States Environmental Protection Agency's (USEPA) reference dose (RfD: 0.7 μg/kg bw/day). This is the first study on perchlorate and iodide levels in whole blood from infants, toddlers, children, adolescents, and adults from a city in China with known high perchlorate levels.

Factors influencing the crystallization of monosodium urate: a systematic literature review.

PubMed

Chhana, Ashika; Lee, Gerald; Dalbeth, Nicola

2015-10-14

Gout is a chronic disease of monosodium urate (MSU) crystal deposition. Although hyperuricaemia is the central risk factor for development of gout, not all people with hyperuricaemia have subclinical MSU crystal deposition or indeed, symptomatic disease. The aim of this systematic literature review was to identify factors that contribute to MSU crystallization. A search was conducted of the electronic databases PubMed, Science Direct and Scopus. Articles were included if they contained original data related to MSU crystallization. The methods and results were summarized and categorized into articles describing at least one of the three key steps in MSU crystallization (reduced urate solubility, nucleation and growth). A total of 2175 articles were initially identified in our systematic search with 35 of these articles included in the final analysis. Elevated urate concentration was identified as a central factor driving all three stages of MSU crystallization. Factors that were found to consistently reduce urate solubility were reduced temperatures, pH 7-9 and various ions including sodium ions. Connective tissue factors including bovine cartilage homogenates and healthy human synovial fluid and serum all enhanced urate solubility. MSU nucleation was found to be increased by a number of factors, including sodium ions, uric acid binding antibodies, and synovial fluid or serum from patients with gout. Other than elevated urate concentrations, no other specific factors were identified as promoters of MSU crystal growth. Increased urate concentration is the key factor required at each stage of MSU crystallization. Different proteins and factors within connective tissues may promote MSU crystallization and may be important for determining the sites at which MSU crystallization occurs in the presence of elevated urate concentrations.

Genetic characterization of moaB mutants of Escherichia coli

PubMed Central

Kozmin, Stanislav G.; Schaaper, Roel M.

2013-01-01

The moaABCDE operon of Escherichia coli encodes enzymes essential for the biosynthesis of the molybdenum cofactor (Moco). However, the role of the moaB gene within this operon has remained enigmatic. Here, we have investigated the effect of moaB defects on two phenotypes diagnostic for Moco-deficiency: chlorate-resistance and sensitivity to the base analog 6-N-hydroxylaminopurine (HAP). We found that transposon insertions in moaB caused partial Moco-deficiency associated with chlorate-resistance, but not for HAP-sensitivity. On the other hand, in-frame deletions of moaB, or moaB overexpression, had no effect on either phenotype. Our combined data are consistent with the lack of any role for MoaB in Moco biosynthesis in E. coli. PMID:23680484

The impact of N,N-dimethyldodecylamine N-oxide (DDAO) concentration on the crystallisation of sodium dodecyl sulfate (SDS) systems and the resulting changes to crystal structure, shape and the kinetics of crystal growth.

PubMed

Summerton, Emily; Hollamby, Martin J; Zimbitas, Georgina; Snow, Tim; Smith, Andrew J; Sommertune, Jens; Bettiol, Jeanluc; Jones, Christopher; Britton, Melanie M; Bakalis, Serafim

2018-05-19

At low temperatures stability issues arise in commercial detergent products when surfactant crystallisation occurs, a process which is not currently well-understood. An understanding of the phase transition can be obtained using a simple binary SDS (sodium dodecyl sulfate) + DDAO (N,N-dimethyldodecylamine N-oxide) aqueous system. It expected that the crystallisation temperature of an SDS system can be lowered with addition of DDAO, thus providing a route to improve detergent stability. Detergent systems are typically comprised of anionic surfactants, non-ionic surfactants and water. This study explores the crystallisation of a three component system consisting of sodium dodecyl sulfate (SDS), N,N-dimethyldodecylamine N-oxide (DDAO), and water using wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and confocal Raman microscopy. The presence of DDAO lowered the crystallisation temperature of a 20 wt% SDS system. For all aqueous mixtures of SDS + DDAO at low temperatures, SDS hydrated crystals, SDS.1/2H 2 O or SDS·H 2 O, formed. SDS hydrates comprising of layers of SDS separated by water layers. DDAO tended to reside in the vicinity of these SDS crystals. In the absence of DDAO an additional intermediary hydrate structure, SDS.1/8H 2 O, formed whereas for mixed SDS + DDAO systems no such structure was detected during crystallisation. Copyright © 2018. Published by Elsevier Inc.

Investigating Dissolution and Precipitation Phenomena with a Smartphone Microscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lumetta, Gregg J.; Arcia, Edgar

A novel smartphone microscope can be used to observe the dissolution and crystallization of sodium chloride at a microscopic level. Observation of these seemingly simple phenomena through the microscope at 100× magnification can actually reveal some surprising behavior. These experiments offer the opportunity to discuss some basic concepts such as how the morphological features of the crystals dictates how the dissolution process proceeds, and how materials can be purified by re-crystallization techniques.

View of salt crystals inserted within a 50mm metal loop in the U.S. Laboratory

NASA Image and Video Library

2003-03-15

ISS006-E-39339 (15 March 2003) --- A close up view of sodium chloride crystals in a water bubble within a 50-millimeter metal loop was photographed by an Expedition Six crewmember. The experiment took place in the Destiny laboratory on the International Space Station (ISS).

Crystal structure of bis­(μ-N-hy­droxy­picolin­amid­ato)bis­[bis­(N-hy­droxy­picolinamide)­sodium

PubMed Central

Safyanova, Inna S.; Ohui, Kateryna A.; Omelchenko, Irina V.

2017-01-01

The title compound, [Na2(C6H5N2O2)2(C6H6N2O2)4], is a centrosymmetric coordination dimer based on the sodium(I) salt of N-hy­droxy­picolinamide. The mol­ecule has an {Na2O6(μ-O)2} core with two bridging carbonyl O atoms and two hydroxamate O atoms of two mono-deprotonated residues of N-hy­droxy­picolinamide, while two neutral N-hy­droxy­picolinamide mol­ecules are coordinated in a monodentate manner to each sodium ion via the carbonyl O atoms [the Na—O distances range from 2.3044 (2) to 2.3716 (2) Å]. The penta­coordinated sodium ion exhibits a distorted trigonal–pyramidal coordination polyhedron. In the crystal, the coordination dimers are linked into chains along the c axis via N—H⋯O and N—H⋯N hydrogen bonds; the chains are linked into a two-dimensional framework parallel to (100) via weak C—H⋯O and π–π stacking inter­actions. PMID:28083127

Design of high-performance cathode materials with single-phase pathway for sodium ion batteries: A study on P2-Nax(LiyMn1-y)O2 compounds

NASA Astrophysics Data System (ADS)

Yang, Lufeng; Li, Xiang; Ma, Xuetian; Xiong, Shan; Liu, Pan; Tang, Yuanzhi; Cheng, Shuang; Hu, Yan-Yan; Liu, Meilin; Chen, Hailong

2018-03-01

Sodium-ion batteries (SIBs) are an emerging electrochemical energy storage technology that has high promise for electrical grid level energy storage. High capacity, long cycle life, and low cost cathode materials are very much desired for the development of high performance SIB systems. Sodium manganese oxides with different compositions and crystal structures have attracted much attention because of their high capacity and low cost. Here we report our investigations into a group of promising lithium doped sodium manganese oxide cathode materials with exceptionally high initial capacity of ∼223 mAh g-1 and excellent capacity retentions, attributed primarily to the absence of phase transformation in a wide potential range of electrochemical cycling, as confirmed by in-operando X-ray diffraction (XRD), Rietveld refinement, and high-resolution 7Li solid-state NMR characterizations. The systematic study of structural evolution and the correlation with the electrochemical behavior of the doped cathode materials provides new insights into rational design of high-performance intercalation compounds by tailoring the composition and the crystal structure evolution in electrochemical cycling.

Deliquescence and crystallization of ammonium sulfate-glutaric acid and sodium chloride-glutaric acid particles

NASA Astrophysics Data System (ADS)

Pant, Atul; Fok, Abel; Parsons, Matthew T.; Mak, Jackson; Bertram, Allan K.

2004-06-01

In the following, we report the deliquescence relative humidities (DRH) and crystallization relative humidities (CRH) of mixed inorganic-organic particles, specifically ammonium sulfate-glutaric acid and sodium chloride-glutaric acid particles. Knowledge of the DRH and CRH of mixed inorganic-organic particles is crucial for predicting the role of aerosol particles in the atmosphere. Our DRH results are in good agreement with previous measurements, but our CRH results are significantly lower than some of the previous measurements reported in the literature. Our studies show that the DRH and CRH of ammonium sulfate and sodium chloride only decreased slightly when the mole fraction of the acid was less than 0.4. If other organics in the atmosphere behave in a similar manner, then the DRH and CRH of mixed inorganic-organic atmospheric particles will only be slightly less than the DRH and CRH of pure inorganic particles when the organic mole fraction is less than 0.4. Our results also show that if the particles contain a significant amount of organics (mole fraction > 0.5) the crystallization relative humidity decreases significantly and the particles are more likely to remain in the liquid state. Further work is needed to determine if other organics species of atmospheric importance have a similar effect.

Molecular organic crystalline matrix for hybrid organic-inorganic (nano) composite materials

NASA Astrophysics Data System (ADS)

Stanculescu, A.; Tugulea, L.; Alexandru, H. V.; Stanculescu, F.; Socol, M.

2005-02-01

Metal-doped benzil crystals have been grown by thermal gradient solidification in a vertical transparent growth configuration to investigate the effect of metallic guest on the ordered organic host. We have identified the conditions for growing homogeneous, optically good crystals of benzil doped with sodium and silver, limiting the effect of supercooling, low thermal conductivity and anisotropy of the growth speed (temperature gradient at the liquid-solid interface: 10-25 °C, moving speed of the growth interface 2.0 mm/h). The nature and concentration of the dopant are parameters affecting, through the growth process, the crystalline perfection and the optical properties of the organic matrix. Bulk optical characterisation, by spectrophotometrical methods, has offered details on some intrinsic properties of the system metal particles/benzil crystalline matrix. Analytical processing of the experimental data emphasised that benzil is a wide optical band gap organic semiconductor Eg=2.65 eV. We also have investigated the effect of sodium and silver on the properties of benzil crystal as potential transparent semiconductor matrix for (nano)composite metal/molecular organic material. With the increase of sodium concentration from c=1 to 6 wt%, a small narrowing of the band gap has been remarked. The same behaviour has been found for benzil doped with silver (c=2 wt%) compared to pure benzil.

The Investigation of Chlorates as a Possible Source of Oxygen and Chlorine Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Sutter, B.; Archer, D. P.; Ming, D. W.; Niles, P. B.; Eigenbrode, J. L.; Franz, H.; Glavin, D. P.; McAdam, A. C.; Mahaffy, P; Stern, J. C.;

Two sodium and lanthanide(III) MOFs based on oxalate and V-shaped 4,4‧-oxybis(benzoate) ligands: Hydrothermal synthesis, crystal structure, and luminescence properties

NASA Astrophysics Data System (ADS)

Wang, Chongchen; Guo, Guangliang; Wang, Peng

2013-01-01

Two lanthanide based metal-organic frameworks, [NaLn(oba)(ox)(H2O)] (Lndbnd6 Eu(1) and Sm(2)) were obtained from 4,4'-oxybisbenzoic acid, sodium oxalate and corresponding lanthanide salts by hydrothermal synthesis. They were characterized by single-crystal X-ray diffraction, IR spectra, and photoluminescent spectra. The crystallographic data reveals that complexes 1 and 2 are isomorphous and isostructural, composed of three-dimensional framework built up of distorted tricapped trigonal EuO9 units, distorted octahedron NaO6 units, 4,4'-oxybis(benzoate) and oxalate. The carboxylate oxygen atoms of the 4,4'-oxybis(benzoate) and oxalate ligand are coordinated to lanthanide ions and sodium ions, resulting into two-dimensional inorganic sheets, which are further linked into three-dimensional network by organic ligands. Thermogravimetric analyses of 1-2 display a considerable thermal stability. Photoluminescent measurements indicated that europium complex 1 displayed strong red emission.

Sodium intercalation in the phosphosulfate cathode NaFe2(PO4)(SO4)2

NASA Astrophysics Data System (ADS)

Ben Yahia, Hamdi; Essehli, Rachid; Amin, Ruhul; Boulahya, Khalid; Okumura, Toyoki; Belharouak, Ilias

2018-04-01

The compound NaFe2(PO4)(SO4)2 is successfully synthesized via a solid state reaction route and its crystal structure is determined using powder X-ray diffraction data. NaFe2(PO4)(SO4)2 phase is also characterized by cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy. NaFe2(PO4)(SO4)2 crystallizes with the well-known NASICON-type structure. SAED and HRTEM experiments confirm the structural model, and no ordering between the PO4-3 and SO4-2 polyanions is detected. The electrochemical tests indicate that NaFe2(PO4)(SO4)2 is a 3 V sodium intercalating cathode. The electrical conductivity is relatively low (2.2 × 10-6 Scm-1 at 200 °C) and the obtained activation energy is ∼0.60eV. The GITT experiments indicate that the diffusivity values are in the range of 10-11-10-12 cm2/s within the measured sodium concentrations.

Nonequilibrium 2-Hydroxyoctadecanoic Acid Monolayers: Effect of Electrolytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lendrum, Conrad D.; Ingham, Bridget; Lin, Binhua

2012-02-06

2-Hydroxyacids display complex monolayer phase behavior due to the additional hydrogen bonding afforded by the presence of the second hydroxy group. The placement of this group at the position {alpha} to the carboxylic acid functionality also introduces the possibility of chelation, a utility important in crystallization including biomineralization. Biomineralization, like many biological processes, is inherently a nonequilibrium process. The nonequilibrium monolayer phase behavior of 2-hydroxyoctadecanoic acid was investigated on each of pure water, calcium chloride, sodium bicarbonate and calcium carbonate crystallizing subphases as a precursor study to a model calcium carbonate biomineralizing system, each at a pH of {approx}6. Themore » role of the bicarbonate co-ion in manipulating the monolayer structure was determined by comparison with monolayer phase behavior on a sodium chloride subphase. Monolayer phase behavior was probed using surface pressure/area isotherms, surface potential, Brewster angle microscopy, and synchrotron-based grazing incidence X-ray diffraction and X-ray reflectivity. Complex phase behavior was observed for all but the sodium chloride subphase with hydrogen bonding, electrostatic and steric effects defining the symmetry of the monolayer. On a pure water subphase hydrogen bonding dominates with three phases coexisting at low pressures. Introduction of calcium ions into the aqueous subphase ensures strong cation binding to the surfactant head groups through chelation. The monolayer becomes very unstable in the presence of bicarbonate ions within the subphase due to short-range hydrogen bonding interactions between the monolayer and bicarbonate ions facilitated by the sodium cation enhancing surfactant solubility. The combined effects of electrostatics and hydrogen bonding are observed on the calcium carbonate crystallizing subphase.« less

Study of the Crystal Structures of Sodium Magnesium and Sodium Nickel Diphosphates

NASA Astrophysics Data System (ADS)

Erragh, Fatima; Boukhari, Ali; Abraham, Francis; Elouadi, Brahim

2000-07-01

Single-crystal X-ray crystallography studies have shown that diphosphates Na3.64Mg2.18(P2O7)2 and Na3.64Ni2.18(P2O7)2 crystallize with the same structural type and the same space group Poverline1. Their triclinic lattice parameters are equal to a=10.901 (2), b=9.765 (2), c=6.382 (1) Å, α=112.43 (1)°, β=99.64 (1)°, γ=107.53 (1)°, Z=2 and a=10.889 (5), b=9.705 (4), c=6.358 (4) Å, α=112.46 (4)°, β=99.92 (4)°, γ=107.54 (4)°, Z=2, respectively. The structure could be regarded as a packing of diphosphate groups [P2O7]4- and [MO6] octahedra (M=Mg, Ni) delimiting cavities and tunnels which host sodium cations. The tunnels are running along [001]. The structure is characterized by mixed (Na, M) sites with an occupation factor ratio equal to ca. 0.82/0.18. Sodium cations are located in five different sites: two cavities (one penta- and the other octa-coordinated) totally occupied and three octahedral interstices, which are partially filled by Na(3), Na(4), and Na(5) according to the respective occupation factors of 0.15, 0.42, and 0.25 for Na3.64Mg2.18(P2O7)2 and 0.13, 0.40, and 0.29 in the case of Na3.64Ni2.18(P2O7)2.

Influence of electrolytes (TEABF4 and TEMABF4) on electrochemical performance of graphite oxide derived from needle coke.

PubMed

Yang, Sunhye; Kim, Ick-Jun; Choi, In-Sik; Bae, Mi-Kyeong; Kim, Hyun-Soo

2013-05-01

The structure of needle coke was changed to graphite oxide structure after oxidation treatment with 70 wt.% of nitric acid and sodium chlorate (NaClO3), and the inter-layer distance of the oxidized needle coke was expanded to 6.9 angstroms. The first charge profile of the oxidized needle coke-cell with 1.2 M TEMABF4/acetonitrile solution displayed that the intercalation of electrolyte ions into the inter-layer occurred at 1.0 V, which value is lower than 1.3 V of the oxidized needle coke-cell with 1.2 M TEABF4/acetonitrile solution. After first charge/discharge, the cell using TEMABF4 electrolyte exhibited smaller electrode resistance of 0.05 omega, and larger specific volume capacitance of 25.5 F/ml at the two-electrode system in the potential range 0-2.5 V than those of the cell using TEABF4 electrolyte. Compared to the TEABF4 electrolyte, better electrochemical performance of the TEMABF4 electrolyte in the oxidized needle coke may be caused by the smaller cation (TEMA+) size and better ion mobility in the nanopores between inter-layers.

Prolonged triboluminescence in clays and other minerals

NASA Technical Reports Server (NTRS)

Lahav, N.; Coyne, L. M.; Lawless, J. G.

1982-01-01

The decay curves of various triboluminescent-excited materials were obtained, including well-crystallized and poorly crystallized kaolin, bentonite, quartz, sodium chloride, and chalk calcite. A qualitative increase in triboluminescence was observed for kaolin dipped in water or tryptophan solution compared to dry kaolin, and for frozen kaolin and montmorillonite pastes. Theoretical explanations for the tryptophan effect are discussed.

Nephrocalcinosis

MedlinePlus

... Blood tests to check levels of calcium, phosphate, uric acid, and parathyroid hormone Urinalysis to see crystals and ... to measure acidity and levels of calcium, sodium, uric acid, oxalate, and citrate

Tetragonal Chicken Egg White Lysozyme Solubility in Sodium Chloride Solutions

NASA Technical Reports Server (NTRS)

Forsythe, Elizabeth L.; Judge, Russell A.; Pusey, Marc L.

1998-01-01

The solubility of chicken egg white lysozyme, crystallized in the tetragonal form was measured in sodium chloride solutions from 1.6 to 30.7 C, using a miniature column solubility apparatus. Sodium chloride solution concentrations ranged from 1 to 7% (w/v). The solutions were buffered with 0.1 M sodium acetate buffer with the solubility being measured at pH values in 0.2 pH unit increments in the range pH 4.0 to 5.4, with data also included at pH 4.5. Lysozyme solubility was found to increase with increases in temperature and decreasing salt concentration. Solution pH has a varied and unpredictable effect on solubility.

Production of sodium-22 from proton irradiated aluminum

DOEpatents

Taylor, Wayne A.; Heaton, Richard C.; Jamriska, David J.

1996-01-01

A process for selective separation of sodium-22 from a proton irradiated minum target including dissolving a proton irradiated aluminum target in hydrochloric acid to form a first solution including aluminum ions and sodium ions, separating a portion of the aluminum ions from the first solution by crystallization of an aluminum salt, contacting the remaining first solution with an anion exchange resin whereby ions selected from the group consisting of iron and copper are selectively absorbed by the anion exchange resin while aluminum ions and sodium ions remain in solution, contacting the solution with an cation exchange resin whereby aluminum ions and sodium ions are adsorbed by the cation exchange resin, and, contacting the cation exchange resin with an acid solution capable of selectively separating the adsorbed sodium ions from the cation exchange resin while aluminum ions remain adsorbed on the cation exchange resin is disclosed.

Crystallization and preliminary X-ray crystallographic analysis of strictosidine synthase from Rauvolfia: the first member of a novel enzyme family.

PubMed

Ma, Xueyan; Koepke, Juergen; Fritzsch, Günter; Diem, Ralf; Kutchan, Toni M; Michel, Hartmut; Stöckigt, Joachim

2004-10-01

Strictosidine synthase is a central enzyme involved in the biosynthesis of almost all plant monoterpenoid indole alkaloids. Strictosidine synthase from Rauvolfia serpentina was heterologously expressed in Escherichia coli. Crystals of the purified recombinant enzyme have been obtained by the hanging-drop technique at 303 K with potassium sodium tartrate tetrahydrate as precipitant. The crystals belong to the space group R3 with cell dimensions of a=b=150.3 A and c=122.4 A. Under cryoconditions (120 K), the crystals diffract to about 2.95 A.

Optical biosensor based on liquid crystal droplets for detection of cholic acid

NASA Astrophysics Data System (ADS)

Niu, Xiaofang; Luo, Dan; Chen, Rui; Wang, Fei; Sun, Xiaowei; Dai, Haitao

2016-12-01

A highly sensitive cholic acid biosensor based on 4-cyano-4‧-penthlbiphenyl (5CB) Liquid crystal droplets in phosphate buffer saline solution was reported. A radial-to-bipolar transition of 5CB droplet would be triggered during competitive reaction of CA at the sodium dodecyl sulfate surfactant-laden 5CB droplet surface. Our liquid crystal droplet sensor is a low-cost, simple and fast method for CA detection. The detection limit (5 μM) of our method is 2.4 times lower than previously report by using liquid crystal film to detection of CA.

Changes in the IR Spectra of Aqueous Solutions of Alkali Metal Chlorides during Crystallization

NASA Astrophysics Data System (ADS)

Koroleva, A. V.; Matveev, V. K.; Koroleva, L. A.; Pentin, Yu. A.

2018-02-01

The IR spectra of aqueous solutions of sodium chloride and rubidium chloride with the same concentration of 0.1 M upon freezing are studied in the middle IR region. The changes that occur in the absorption bands of the bending ν2, compound ν2 + νL, and stretching (ν1, 2ν2, and ν3) vibrations of water molecules with gradual crystallization of the solutions are studied. The obtained spectra of crystallized solutions are compared to the IR spectrum of ice Ih. Analysis allows conclusions about the structure of the investigated frozen crystallized solutions.

Orientation distribution of sheared isotactic polypropylene plates through thickness in the presence of sodium benzoate

NASA Astrophysics Data System (ADS)

Zhu, Peng-wei; Phillips, Andrew; Tung, Jason; Edward, Graham

2005-05-01

The orientation distribution of sheared isotactic polypropylene (iPP) containing different amount of sodium benzoate (SB) has been investigated through the gradient of shear flow field using microbeam of synchrotron wide-angle x-ray techniques. The degree of the overall orientation of α-phase crystal is found to increase with increasing concentration of SB. Compared with the sheared iPP in the absence of SB, the orientation of α-phase crystal is found to distribute over a broader range of shear flow field in the presence of SB. The overall orientation of α-phase crystal is explained in terms of a parent-daughter model or lamella-branched shish-kebab structure. As the concentration of SB increases, the contribution from the c-axis orientation of parent lamellae decreases in the flow direction. The contribution from the a*-axis orientation of daughter lamellae is developed to be dominant in the flow direction when the concentration of SB exceeds a critical value.

Transport phenomena in the crystallization of lysozyme by osmotic dewatering and liquid-liquid diffusion in low gravity

NASA Technical Reports Server (NTRS)

Todd, Paul; Sportiello, Michael G.; Gregory, Derek; Cassanto, John M.; Alvarado, Ulises A.; Ostroff, Robert; Korszun, Z. R.

1993-01-01

Two methods of protein crystallization, osmotic dewatering and liquid-liquid diffusion, like the vapor diffusion (hanging-drop and sessile-drop) methods allow a gradual approach to supersaturation conditions. The crystallization of hen egg-white lysozyme, an extensively characterized protein crystal, in the presence of sodium chloride was used as an experimental model with which to compare these two methods in low gravity and in the laboratory. Comparisons of crystal growth rates by the two methods under the two conditions have, to date, indicated that the rate of crystal growth by osmotic dewatering is nearly the same in low gravity and on the ground, while much faster crystal growth rates can be achieved by the liquid-liquid diffusion method in low gravity.

Influence of pH and method of crystallization on the solid physical form of indomethacin.

PubMed

Dubbini, Alessandra; Censi, Roberta; Martena, Valentina; Hoti, Ela; Ricciutelli, Massimo; Malaj, Ledjan; Di Martino, Piera

2014-10-01

The purpose of this study was to investigate the effect of pH and method of crystallization on the solid physical form of indomethacin (IDM). IDM, a non steroidal anti-inflammatory drug poorly soluble in water, underwent two different crystallization methods: crystallization by solvent evaporation under reduced pressure at 50.0°C (method A), and crystallization by cooling of solution from 50.0 to 5.0°C (method B). In both cases, several aqueous ethanolic solutions of IDM of different pHs were prepared. pHs were adjusted by adding acidic solutions (HCl 2M) or alkali (NaOH or NH4OH 2M) to an aqueous ethanolic solution of IDM. Thus, several batches were recovered after crystallization. The chemical stability of IDM was verified through (1)H NMR and mass spectroscopy (FIA-ESI-MS), that revealed that IDM degraded in strong alkali media (pH ≥ 12). Crystals obtained under different crystallization conditions at pHs of 1.0, 4.5, 7.0, 8.0, 10.0 and chemically stable were thus characterized for crystal habit by scanning electron microscopy, for thermal behaviour by differential scanning calorimetry, and thermogravimetry, and for solid state by X-ray powder diffractometry. Under the Method A, IDM always crystallized into pure metastable alpha form when solutions were acidified or alkalized respectively with HCl and NH4OH. On the contrary, in presence of NaOH, IDM crystallized under a mixture of alpha and sodium trihydrate form, because the presence of the sodium counter ion orientates the crystallization towards the formation of the trihydrate salt. Under the method B, at pH of 1.0, IDM crystallized under the alpha form; at pH 4.5, IDM crystallized under the form alpha in presence of some nuclei of gamma form; at pH 7.0, 8.0, and 10.0 for NH4OH, IDM crystallized under the most stable polymorph gamma form, whereas in presence of NaOH, a mix of alpha, and salt forms was formed whatever the pH of the solution. Copyright © 2014 Elsevier B.V. All rights reserved.

Applicability of salt reduction strategies in pizza crust.

PubMed

Mueller, Eva; Koehler, Peter; Scherf, Katharina Anne

2016-02-01

In an effort to reduce population-wide sodium intake from processed foods, due to major health concerns, several different strategies for sodium reduction in pizza crust without any topping were evaluated by sensory analyses. It was possible to reduce sodium by 10% in one single step or to replace 30% of NaCl by KCl without a noticeable loss of salty taste. The late addition of coarse-grained NaCl (crystal size: 0.4-1.4 mm) to pizza dough led to an enhancement of saltiness through taste contrast and an accelerated sodium delivery measured in the mouth and in a model mastication simulator. Likewise, the application of an aqueous salt solution to one side of the pizza crust led to an enhancement of saltiness perception through faster sodium availability, leading to a greater contrast in sodium concentration. Each of these two strategies allowed a sodium reduction of up to 25% while maintaining taste quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Aluminum Citrate Prevents Renal Injury from Calcium Oxalate Crystal Deposition

PubMed Central

Besenhofer, Lauren M.; Cain, Marie C.; Dunning, Cody

2012-01-01

Calcium oxalate monohydrate crystals are responsible for the kidney injury associated with exposure to ethylene glycol or severe hyperoxaluria. Current treatment strategies target the formation of calcium oxalate but not its interaction with kidney tissue. Because aluminum citrate blocks calcium oxalate binding and toxicity in human kidney cells, it may provide a different therapeutic approach to calcium oxalate-induced injury. Here, we tested the effects of aluminum citrate and sodium citrate in a Wistar rat model of acute high-dose ethylene glycol exposure. Aluminum citrate, but not sodium citrate, attenuated increases in urea nitrogen, creatinine, and the ratio of kidney to body weight in ethylene glycol–treated rats. Compared with ethylene glycol alone, the addition of aluminum citrate significantly increased the urinary excretion of both crystalline calcium and crystalline oxalate and decreased the deposition of crystals in renal tissue. In vitro, aluminum citrate interacted directly with oxalate crystals to inhibit their uptake by proximal tubule cells. These results suggest that treating with aluminum citrate attenuates renal injury in rats with severe ethylene glycol toxicity, apparently by inhibiting calcium oxalate’s interaction with, and retention by, the kidney epithelium. PMID:23138489

EPR and optical absorption studies of paramagnetic molecular ion (VO2+) in Lithium Sodium Acid Phthalate single crystal

NASA Astrophysics Data System (ADS)

Subbulakshmi, N.; Kumar, M. Saravana; Sheela, K. Juliet; Krishnan, S. Radha; Shanmugam, V. M.; Subramanian, P.

2017-12-01

Electron Paramagnetic Resonance (EPR) spectroscopic studies of VO2+ ions as paramagnetic impurity in Lithium Sodium Acid Phthalate (LiNaP) single crystal have been done at room temperature on X-Band microwave frequency. The lattice parameter values are obtained for the chosen system from Single crystal X-ray diffraction study. Among the number of hyperfine lines in the EPR spectra only two sets are reported from EPR data. The principal values of g and A tensors are evaluated for the two different VO2+ sites I and II. They possess the crystalline field around the VO2+ as orthorhombic. Site II VO2+ ion is identified as substitutional in place of Na1 location and the other site I is identified as interstitial location. For both sites in LiNaP, VO2+ are identified in octahedral coordination with tetragonal distortion as seen from the spin Hamiltonian parameter values. The ground state of vanadyl ion in the LiNaP single crystal is dxy. Using optical absorption data the octahedral and tetragonal parameters are calculated. By correlating EPR and optical data, the molecular orbital bonding parameters have been discussed for both sites.

46 CFR 148.150 - Stowage and segregation for materials of Class 9.

Code of Federal Regulations, 2011 CFR

2011-10-01

... by this section. (b) Ammonium nitrate fertilizer of Class 9 must be segregated as required for Class... hold or compartment from readily combustible materials, chlorates, hypochlorites, nitrites...

A Reaction Involving Oxygen and Metal Sulfides.

ERIC Educational Resources Information Center

Hill, William D. Jr.

1986-01-01

Describes a procedure for oxygen generation by thermal decomposition of potassium chlorate in presence of manganese dioxide, reacted with various sulfides. Provides a table of sample product yields for various sulfides. (JM)

Development of dried serum spot sampling techniques for the assessment of trace elements in serum samples by LA-ICP-MS.

PubMed

Chantada-Vázquez, María Pilar; Moreda-Piñeiro, Jorge; Cantarero-Roldán, Alicia; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2018-08-15

A novel approach for serum analysis by dried matrix spot (DMS) technique is proposed. The methodology consists of sampling filter paper discs (2.7 mm in diameter) containing the large amount of serum retained after a single spotting. Several oxidizers (sodium chlorate, sodium azide, acetic acid, formic acid, 1-butyl-3-methylimidazoliumm chloride/bromide) were tested (oxidizers premixed with the sample before spotting, and papers previously soaked in concentrated additive/oxidizer solutions). Direct multi-element determination (Al, Be, Ca, Cu, Fe, K, Li, Mg, Mn, Mo, Na, P, Rb, Se, V, and Zn) in dried serum spots at very low levels was therefore assessed by laser ablation (LA) coupled with inductively coupled plasma - mass spectrometry (ICP-MS). Laser ablation was performed using a focused Nd: YAG laser beam in lineal scan mode (wavelength 213 nm, laser fluency 2.2 J cm -2 , repetition rate 20 Hz, laser spot diameter 90 µm, depth 0 µm, scanning speed 12 µm s -1 ). Matrix-matched calibration mode and 13 C as internal standard (for signal intensities normalization) was used throughout the work. Limits of quantification were found to be from 21 µg L -1 to 221 mg L -1 . Repeatability (seven ablations of the same dried serum spot) and reproducibility (two ablations of seven dried serum spot from the same material) offered RSDs below 12% for all analytes, which seems satisfactory for clinical purposes. The method was validated by analyzing several certified reference materials (Seronorm™ level I and II trace elements in serum), and it was applied to several DMS from serum samples from healthy adults. Copyright © 2018 Elsevier B.V. All rights reserved.

Wet calcining of trona (sodium sesquicarbonate) and bicarbonate in a mixed solvent

NASA Astrophysics Data System (ADS)

Gärtner, R. S.; Witkamp, G. J.

2002-04-01

Trona ore is used in large amounts for the production of soda ash. A key step in this process is the conversion of trona (sodium sesquicarbonate: Na 2CO 3·NaHCO 3·2H 2O) into soda (sodium carbonate anhydrate: Na 2CO 3). Currently, this conversion is done industrially by calcining of the raw ore in rotary calciners at ca. 120°C or higher (Natural Soda Ash—Occurrences, Processing, and Use, Van Nostrand Reinhold, New York, 1991, p. 267). Trona can however be converted at lower temperatures by using a "wet calcining" technique. In this technique, trona is contacted with an organic or mixed organic-aqueous solvent at a conversion temperature that depends on the water activity of the used solvent. In pure ethylene glycol this temperature can be as low as 55°C. The conversion by "wet calcining" occurs very similar to that in the regular dry calcining process via a solid phase conversion. The anhydrate crystals form directly from the solid trona. This produces pseudomorphs (J. Chem. Eng. Data 8(3) (1963) 301), i.e. agglomerates of fine anhydrate crystals (1-10 μm). At high temperatures, dense, finely pored agglomerates are formed, while the outer shape of the agglomerate retains the prism shape of the trona crystal. At low conversion temperatures, loosely packed or even unstable agglomerates are found.

Mild hydrothermal crystal growth of new uranium(IV) fluorides, Na3.13Mg1.43U6F30 and Na2.50Mn1.75U6F30: Structures, optical and magnetic properties

NASA Astrophysics Data System (ADS)

Yeon, Jeongho; Smith, Mark D.; Tapp, Joshua; Möller, Angela; zur Loye, Hans-Conrad

2016-04-01

Two new uranium(IV) fluorides, Na3.13Mg1.43U6F30 (1) and Na2.50Mn1.75U6F30 (2), were synthesized through an in situ mild hydrothermal route, and were structurally characterized by single crystal X-ray diffraction. The compounds exhibit complex crystal structures composed of corner- or edge-shared UF9 and MF6 (M=Mg, Mn) polyhedra, forming hexagonal channels in the three-dimensional framework, in which ordered or disordered divalent metal and sodium atoms reside. The large hexagonal voids contain the nearly regular M(II)F6 octahedra and sodium ions, whereas the small hexagonal cavities include M(II) and sodium ions on a mixed-occupied site. Magnetic susceptibility measurements yielded effective magnetic moments of 8.36 and 11.6 μB for 1 and 2, respectively, confirming the presence and oxidation states of U(IV) and Mn(II). The large negative Weiss constants indicate the spin gap between a triplet and a singlet state in the U(IV). Magnetization data as a function of applied fields revealed that 2 exhibits paramagnetic behavior due to the nonmagnetic singlet ground state of U(IV) at low temperature. UV-vis diffuse reflectance and X-ray photoelectron spectroscopy data were also analyzed.

Coupled adsorption-photocatalytic degradation of crystal violet under sunlight using chemically synthesized grafted sodium alginate/ZnO/graphene oxide composite.

PubMed

Mohamed, S K; Hegazy, Sh H; Abdelwahab, N A; Ramadan, A M

2018-03-01

This research aimed to synthesize natural polymer nanocomposite and employ it for coupled adsorption- photocatalytic degradation of crystal violet. Sodium alginate-g-poly (acrylic acid-co-cinnamic acid) and its composites with ZnO nanorods and graphene oxide sheets were synthesized and characterized using FT-IR, XRD, SEM, HR-TEM and DR/UV-vis spectroscopy. The adsorption efficiency of samples for crystal violet has been studied in the dark. The effect of different parameters as pH, initial dye concentration, contact time and temperature on the adsorption efficiency of the synthesized sample has been examined. Kinetics studies showed that the adsorption of all samples was well described by the pseudo-second-order model and the equilibrium adsorption results fitted Freundlich model. The maximum adsorption capacity achieved at pH 5.0 was 13.85 mg g -1 . Thermodynamic studies exhibited that the adsorption is spontaneous, endothermic in nature and leads to higher entropy. Coupled adsorption-photocatalytic degradation studies under sunlight showed an enhancement in the removal efficiency by 10%. In the case of sodium alginate-g-poly (acrylic acid-co-cinnamic acid)/ZnO/graphene oxide composite, the removal efficiency after 5 h under sunlight was 94% versus 84% in the dark. Copyright © 2017 Elsevier B.V. All rights reserved.

An Efficient Composition for Bengal Lights.

ERIC Educational Resources Information Center

Comet, M.; Schreyeck, L.; Fuzellier, H.

2002-01-01

Reports the discovery of an efficient base composition for making bengal lights that is obtained with potassium chlorate and thiourea. Combining this mixture with appropriate flame coloring can produce several impressive bengal lights. (DDR)

49 CFR 173.54 - Forbidden explosives.

Code of Federal Regulations, 2011 CFR

2011-10-01

... detonator. (h) Fireworks containing yellow or white phosphorus. (i) A toy torpedo, the maximum outside dimension of which exceeds 23 mm (0.906 inch), or a toy torpedo containing a mixture of potassium chlorate...

49 CFR 173.54 - Forbidden explosives.

Code of Federal Regulations, 2010 CFR

2010-10-01

... detonator. (h) Fireworks containing yellow or white phosphorus. (i) A toy torpedo, the maximum outside dimension of which exceeds 23 mm (0.906 inch), or a toy torpedo containing a mixture of potassium chlorate...

Making Sparklers: An Introductory Laboratory Experiment

NASA Astrophysics Data System (ADS)

Keeney, Allen; Walters, Christina; Cornelius, Richard D.

1995-07-01

A laboratory experiment consisting of the preparation of sparklers has been developed as part of a project which organizes the general chemistry sequence according to subjects with which students are familiar. This laboratory makes use of oxidation/reduction chemistry to produce a product familiar to students. The result is a mixture rather than a compound, but the composition must be carefully measured to produce a sparkler that will stay lit and produce sparks. The dramatic reaction may be the most impressive and memorable experience that students encounter in the laboratory. Sparklers are formulated from iron, magnesium, and aluminum powders, plus potassium chlorate and barium nitrate held on thick iron wire by a starch paste. At elevated temperatures metal nitrates and chlorates decompose to produces gases, providing the necessary force to eject bits of powdered, burning metal into the air.

Toxic Byproduct Formation during Electrochemical Treatment of Latrine Wastewater

PubMed Central

2017-01-01

Electrochemical systems are an attractive option for onsite latrine wastewater treatment due to their high efficiency and small footprint. While concerns remain over formation of toxic byproducts during treatment, rigorous studies examining byproduct formation are lacking. Experiments treating authentic latrine wastewater over variable treatment times, current densities, chloride concentrations, and anode materials were conducted to characterize byproducts and identify conditions that minimize their formation. Production of inorganic byproducts (chlorate and perchlorate) and indicator organic byproducts (haloacetic acids and trihalomethanes) during electrolysis dramatically exceeded recommendations for drinking water after one treatment cycle (∼10–30 000 times), raising concerns for contamination of downstream water supplies. Stopping the reaction after ammonium was removed (i.e., the chlorination breakpoint) was a promising method to minimize byproduct formation without compromising disinfection and nutrient removal. Though treatment was accelerated at increased chloride concentrations and current densities, byproduct concentrations remained similar near the breakpoint. On TiO2/IrO2 anodes, haloacetic acids (up to ∼50 μM) and chlorate (up to ∼2 μM) were of most concern. Although boron-doped diamond anodes mineralized haloacetic acids after formation, high production rates of chlorate and perchlorate (up to ∼4 and 25 μM) made them inferior to TiO2/IrO2 anodes in terms of toxic byproduct formation. Organic byproduct formation was similar during chemical chlorination and electrolysis of wastewater, suggesting that organic byproducts are formed by similar pathways in both cases (i.e., reactions with chloramines and free chlorine). PMID:28538093

Toxic Byproduct Formation during Electrochemical Treatment of Latrine Wastewater.

PubMed

Jasper, Justin T; Yang, Yang; Hoffmann, Michael R

2017-06-20

Electrochemical systems are an attractive option for onsite latrine wastewater treatment due to their high efficiency and small footprint. While concerns remain over formation of toxic byproducts during treatment, rigorous studies examining byproduct formation are lacking. Experiments treating authentic latrine wastewater over variable treatment times, current densities, chloride concentrations, and anode materials were conducted to characterize byproducts and identify conditions that minimize their formation. Production of inorganic byproducts (chlorate and perchlorate) and indicator organic byproducts (haloacetic acids and trihalomethanes) during electrolysis dramatically exceeded recommendations for drinking water after one treatment cycle (∼10-30 000 times), raising concerns for contamination of downstream water supplies. Stopping the reaction after ammonium was removed (i.e., the chlorination breakpoint) was a promising method to minimize byproduct formation without compromising disinfection and nutrient removal. Though treatment was accelerated at increased chloride concentrations and current densities, byproduct concentrations remained similar near the breakpoint. On TiO 2 /IrO 2 anodes, haloacetic acids (up to ∼50 μM) and chlorate (up to ∼2 μM) were of most concern. Although boron-doped diamond anodes mineralized haloacetic acids after formation, high production rates of chlorate and perchlorate (up to ∼4 and 25 μM) made them inferior to TiO 2 /IrO 2 anodes in terms of toxic byproduct formation. Organic byproduct formation was similar during chemical chlorination and electrolysis of wastewater, suggesting that organic byproducts are formed by similar pathways in both cases (i.e., reactions with chloramines and free chlorine).

Genome analysis and physiological comparison of Alicycliphilus denitrificans strains BC and K601T

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oosterkamp, Margreet J.; Veuskens, Teun; Saia, Flavia Talarico

2013-01-01

The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601T have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601T is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601T are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacteriummore » that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601T and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601T. Genes involved in cyclohexanol degradation were only found in strain K601T. Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far.« less

Genome Analysis and Physiological Comparison of Alicycliphilus denitrificans Strains BC and K601T

PubMed Central

Talarico Saia, Flávia; Weelink, Sander A. B.; Goodwin, Lynne A.; Daligault, Hajnalka E.; Bruce, David C.; Detter, John C.; Tapia, Roxanne; Han, Cliff S.; Land, Miriam L.; Hauser, Loren J.; Langenhoff, Alette A. M.; Gerritse, Jan; van Berkel, Willem J. H.; Pieper, Dietmar H.; Junca, Howard; Smidt, Hauke; Schraa, Gosse; Davids, Mark; Schaap, Peter J.; Plugge, Caroline M.; Stams, Alfons J. M.

2013-01-01

The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601T have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601T is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601T are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacterium that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601T and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601T. Genes involved in cyclohexanol degradation were only found in strain K601T. Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far. PMID:23825601

X-ray structures of LeuT in substrate-free outward-open and apo inward-open states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnamurthy, Harini; Gouaux, Eric

2012-08-09

Neurotransmitter sodium symporters are integral membrane proteins that remove chemical transmitters from the synapse and terminate neurotransmission mediated by serotonin, dopamine, noradrenaline, glycine and GABA ({gamma}-aminobutyric acid). Crystal structures of the bacterial homologue, LeuT, in substrate-bound outward-occluded and competitive inhibitor-bound outward-facing states have advanced our mechanistic understanding of neurotransmitter sodium symporters but have left fundamental questions unanswered. Here we report crystal structures of LeuT mutants in complexes with conformation-specific antibody fragments in the outward-open and inward-open states. In the absence of substrate but in the presence of sodium the transporter is outward-open, illustrating how the binding of substrate closes themore » extracellular gate through local conformational changes: hinge-bending movements of the extracellular halves of transmembrane domains 1, 2 and 6, together with translation of extracellular loop 4. The inward-open conformation, by contrast, involves large-scale conformational changes, including a reorientation of transmembrane domains 1, 2, 5, 6 and 7, a marked hinge bending of transmembrane domain 1a and occlusion of the extracellular vestibule by extracellular loop 4. These changes close the extracellular gate, open an intracellular vestibule, and largely disrupt the two sodium sites, thus providing a mechanism by which ions and substrate are released to the cytoplasm. The new structures establish a structural framework for the mechanism of neurotransmitter sodium symporters and their modulation by therapeutic and illicit substances.« less

A SEARCH FOR THE DECAY $mu$$Yields$e+$nu$ $gamma$

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frankel, S.; Frati, W.; Halpern, J.

1963-02-16

A search for the decay mu min gave no sig e + gamma is made using spark chambers and sodium iodide crystals. The spark chambers provide the means of measuring the angle between the electron and photon, while the sodium iodide crystals are used to measure the particle energies. A lithium target and thin (0.001 in.) aluminum foils in the spark chamber are used to minimize the scattering of the electron. An upper limit of 4.3, 10/sup -8/ (90% confidence) is found for the ratio of the rate of the mu min gave no sig e + gamma decay tomore » the normal muon decay rate. A search for the decay mu min gave no sig e + gamma + gamma is also made. (auth)« less

Crystallization of Chicken Egg White Lysozyme from Sulfate Salts

NASA Technical Reports Server (NTRS)

Forsythe, Elizabeth; Pusey, Marc

1998-01-01

It has been "known" that chicken egg white lysozyme does not crystallize from sulfate, particularly ammonium sulfate, salts, but instead gives amorphous precipitates. This has been the basis of several studies using lysozyme comparing macromolecule crystal nucleation and amorphous precipitation. Recently Ries-Kautt et al (Acta Cryst D50, (1994) 366) have shown that purified isoionic CEWL could be crystallized from low concentrations of sulfate at basic pH, and we subsequently showed that in fact CEWL could be purified in both the tetragonal and orthorhombic forms using ammonium sulfate over the pH range 4.0 to 7.8 (Acta Cryst D53, (1997) 795). We have now extended these observations to include a range of common sulfate salts, specifically sodium, potassium, rubidium, magnesium, and manganese sulfates. In all cases but the manganese sulfates both the familiar tetragonal and orthorhombic forms were obtained, with unit cell dimensions close to those known for the "classic" sodium chloride crystallized forms. Manganese sulfate has only yielded orthorhombic crystals to date. All crystallizations were carried out using low (typically less than or equal to 6 M) salt and high (greater than approximately 90 mg/ml) protein concentrations. As with ammonium sulfate, the tetragonal - orthorhombic phase shift appears to be a function of both the temperature and the protein concentration, with higher temperatures and concentrations favoring the orthorhombic and lower the tetragonal form. The phase change range is somewhat reduced for the sulfate salts, depending upon conditions being typically between approximately 15 - 20 C. Both the magnesium and manganese sulfates gave crystals at salt concentrations over 0.6 M as well, with magnesium sulfate giving a very slowly nucleating and growing hexagonal form. A triclinic crystal form, characterized by aggressively small crystals (typically 0.1 mm in size) has been occasionally obtained from ammonium sulfate. Finally, preliminary spot solubility determinations have suggested that in some cases the solubility increases with increasing salt concentrations.

NaAlTi 3O 8, A Novel Anode Material for Sodium Ion Battery

DOE PAGES

Ma, Xuetian; An, Ke; Bai, Jianmin; ...

2017-03-13

Sodium ion batteries are being considered as an alternative to lithium ion batteries in large-scale energy storage applications owing to the low cost. In this paper, a novel titanate compound, NaAlTi 3O 8, was successfully synthesized and tested as a promising anode material for sodium ion batteries. Powder X-ray Diffraction (XRD) and refinement were used to analyze the crystal structure. Electrochemical cycling tests under a C/10 rate between 0.01 - 2.5 V showed that ~83 mAh/g capacity could be achieved in the second cycle, with ~75% of which retained after 100 cycles, which corresponds to 0.75 Na + insertion andmore » extraction. The influence of synthesis conditions on electrochemical performances was investigated and discussed. Finally, NaAlTi 3O 8 not only presents a new anode material with low average voltage of ~0.5 V, but also provides a new type of intercalation anode with a crystal structure that differentiates from the anodes that have been reported.« less

Hopper Growth of Salt Crystals.

PubMed

Desarnaud, Julie; Derluyn, Hannelore; Carmeliet, Jan; Bonn, Daniel; Shahidzadeh, Noushine

2018-06-07

The growth of hopper crystals is observed for many substances, but the mechanism of their formation remains ill understood. Here we investigate their growth by performing evaporation experiments on small volumes of salt solutions. We show that sodium chloride crystals that grow very fast from a highly supersaturated solution form a peculiar form of hopper crystal consisting of a series of connected miniature versions of the original cubic crystal. The transition between cubic and such hopper growth happens at a well-defined supersaturation where the growth rate of the cubic crystal reaches a maximum (∼6.5 ± 1.8 μm/s). Above this threshold, the growth rate varies as the third power of supersaturation, showing that a new mechanism, controlled by the maximum speed of surface integration of new molecules, induces the hopper growth of cubic crystals in cascade.

Comparison of lead removal behaviors and generation of water-soluble sodium compounds in molten lead glass under a reductive atmosphere

NASA Astrophysics Data System (ADS)

Okada, Takashi; Nishimura, Fumihiro; Xu, Zhanglian; Yonezawa, Susumu

2018-06-01

We propose a method of reduction-melting at 1000 °C, using a sodium-based flux, to recover lead from cathode-ray tube funnel glass. To recover the added sodium from the treated glass, we combined a reduction-melting process with a subsequent annealing step at 700 °C, generating water-soluble sodium compounds in the molten glass. Using this combined process, this study compares lead removal behavior and the generation of water-soluble sodium compounds (sodium silicates and carbonates) in order to gain fundamental information to enhance the recovery of both lead and sodium. We find that lead removal increases with increasing melting time, whereas the generation efficiency of water-soluble sodium increases and decreases periodically. In particular, near 90% lead removal, the generation of water-soluble sodium compounds decreased sharply, increasing again with the prolongation of melting time. This is due to the different crystallization and phase separation efficiencies of water-soluble sodium in molten glass, whose structure continuously changes with lead removal. Previous studies used a melting time of 60 min in the processes. However, in this study, we observe that a melting time of 180 min enhances the water-soluble sodium generation efficiency.

Formation and properties of metallic nanoparticles in lithium and sodium fluorides with radiation-induced color centers

NASA Astrophysics Data System (ADS)

Bryukvina, L. I.; Martynovich, E. F.

2012-12-01

The specific features of light- and temperature-induced formation of metallic nanoparticles in γ-irradiated LiF and NaF crystals have been investigated. Atomic force microscope images of nanoparticles of different sizes and in different locations have been presented. The relation between the crystal processing regimes and properties of the nanoparticles formed has been revealed. The optical properties of the processed crystals have been analyzed. The thermo- and light-stimulated processes underlying the formation of metallic nanoparticles in aggregation of the color centers and their decay due to the recovery of the crystal lattice have been studied.

SdsA polymorph isolation and improvement of their crystal quality using nonconventional crystallization techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

De la Mora, Eugenio; Flores-Hernández, Edith; Jakoncic, Jean

SdsA, a sodium dodecyl sulfate hydrolase, from Pseudomonas aeruginosa was crystallized in three different crystal polymorphs and their three-dimensional structure was determined. The different polymorphs present different crystal packing habits. One of the polymorphs suggests the existence of a tetramer, an oligomeric state not observed previously, while the crystal packing of the remaining two polymorphs obstructs the active site entrance but stabilizes flexible regions of the protein. Nonconventional crystallization methods that minimize convection, such as counterdiffusion in polyvinyl alcohol gel coupled with the influence of a 500 MHz (10.2 T) magnetic field, were necessary to isolate the poorest diffracting polymorphmore » and increase its internal order to determine its structure by X-ray diffraction. In conclusion, the results obtained show the effectiveness of nonconventional crystallographic methods to isolate different crystal polymorphs.« less

Crystallization and preliminary X-ray analysis of gamma-glutamyltranspeptidase from Escherichia coli K-12.

PubMed

Kumagai, H; Nohara, S; Suzuki, H; Hashimoto, W; Yamamoto, K; Sakai, H; Sakabe, K; Fukuyama, K; Sakabe, N

1993-12-20

gamma-Glutamyltranspeptidase (EC 2.3.2.2) from Escherichia coli K-12 has been purified and crystallized by means of vapor diffusion in hanging drops. Two kinds of crystals on cell dimensions were found for X-ray diffraction analysis, one from ammonium sulfate and the other from polyethylene glycol 6000 as precipitants. The crystals of the orthorhombic form grown in the presence of 15% polyethylene glycol and 20 mM sodium acetate buffer were chosen for further analysis. The crystals belonged to space group P2(1)2(1)2(1), with cell dimensions of a = 128.1, b = 129.9 and c = 79.2 A, and two molecules constitute an asymmetric unit. These crystals diffracted to 2.0 A resolution and were suitable for X-ray crystallographic studies.

Comparison of portable crewmember protective breathing equipment (CPBE) designs.

DOT National Transportation Integrated Search

1993-04-01

CPBE presently certified for transport category aircraft employ 3 types of oxygen production systems: chlorate candle, potassium superoxide, and compressed oxygen. CPBE performance was evaluated to expose significant differences based on this distinc...

Crystallization of sodium chloride from a concentrated calcium chloride-potassium chloride-sodium chloride solution in a CMSMPR crystallizer: Observation of crystal size distribution and model validation

NASA Astrophysics Data System (ADS)

Choi, Byung Sang

Compared to overwhelming technical data available in other advanced technologies, knowledge about particle technology, especially in particle synthesis from a solution, is still poor due to the lack of available equipment to study crystallization phenomena in a crystallizer. Recent technical advances in particle size measurement such as Coulter counter and laser light scattering have made in/ex situ study of some of particle synthesis, i.e., growth, attrition, and aggregation, possible with simple systems. Even with these advancements in measurement technology, to grasp fully the crystallization phenomena requires further theoretical and technical advances in understanding such particle synthesis mechanisms. Therefore, it is the motive of this work to establish the general processing parameters and to produce rigorous experimental data with reliable performance and characterization that rigorously account for the crystallization phenomena of nucleation, growth, aggregation, and breakage including their variations with time and space in a controlled continuous mixed-suspension mixed-product removal (CMSMPR) crystallizer. This dissertation reports the results and achievements in the following areas: (1) experimental programs to support the development and validation of the phenomenological models and generation of laboratory data for the purpose of testing, refining, and validating the crystallization process, (2) development of laboratory well-mixed crystallizer system and experimental protocols to generate crystal size distribution (CSD) data, (3) the effects of feed solution concentration, crystallization temperature, feed flow rate, and mixing speed, as well as different types of mixers resulting in the evolution of CSDs with time from a concentrated brine solution, (4) with statistically designed experiments the effects of processing variables on the resultant particle structure and CSD at steady state were quantified and related to each of those operating conditions by studying the detailed crystallization processes, such as nucleation, growth, and breakage, as well as agglomeration. The purification of CaCl2 solution involving the crystallization of NaCl from the solution mixture of CaCl2, KCl, and NaCl as shipped from Dow Chemical, Ludington, in a CMSMPR crystallizer was studied as our model system because of its nucleation and crystal growth tendencies with less agglomeration. This project also generated a significant body of experimental data that are available at URL that is http://www.che.utah.edu/˜ring/CrystallizationWeb.

Synthesis, crystal structure and magnetic properties of a novel tetranuclear oxo-bridged iron(III) butterfly

NASA Astrophysics Data System (ADS)

Arizaga, Livia; Gancheff, Jorge S.; Faccio, Ricardo; Cañón-Mancisidor, Walter; González, Ricardo; Kremer, Carlos; Chiozzone, Raúl

2014-01-01

A novel carboxylate/picolinate oxo-bridged iron(III) cluster, namely [Na2(H2O)8][Fe4(μ-O)2(O2CPh)7(pic)2]2·2H2O (1) where pic = picolinate, has been obtained by reacting "basic iron benzoate" [Fe3O(O2CPh)6(H2O)3](O2CPh) with sodium picolinate in acetonitrile. The compound has been characterized by elemental analysis and IR spectroscopy and its crystal structure has been determined by single-crystal X-ray diffraction.

Technology Study on Piezoelectric Materials

DTIC Science & Technology

1979-07-20

broken down into five classes: 1) perovskite -type oxides, 2) aqueous solution grown crystals, 3) semiconductive compounds, 4) other oxides and 5...three times that of sodium, sodium would 24 be heated three times as much as water by identical x-rays. " Perovskite -Type Oxides Sixteen of the materials...in Table 1 have the general formula ABD3 which normally have a distorted perovskite , simple cubic structure. The A-type cation at the 12

[Mechanisms of action of voltage-gated sodium channel ligands].

PubMed

Tikhonov, D B

2007-05-01

The voltage-gated sodium channels play a key role in the generation of action potential in excitable cells. Sodium channels are targeted by a number of modulating ligands. Despite numerous studies, the mechanisms of action of many ligands are still unknown. The main cause of the problem is the absence of the channel structure. Sodium channels belong to the superfamily of P-loop channels that also the data abowt includes potassium and calcium channels and the channels of ionotropic glutamate receptors. Crystallization of several potassium channels has opened a possibility to analyze the structure of other members of the superfamily using the homology modeling approach. The present study summarizes the results of several recent modelling studies of such sodium channel ligands as tetrodotoxin, batrachotoxin and local anesthetics. Comparison of available experimental data with X-ray structures of potassium channels has provided a new level of understanding of the mechanisms of action of sodium channel ligands and has allowed proposing several testable hypotheses.

TUNGSTEN BRONZE RELATED NON-NOBLE ELECTROCATALYSTS.

DTIC Science & Technology

FUEL CELLS, *CATALYSTS), (*OXYGEN, *ELECTRODES), (* SILICIDES , ELECTRODES), (*CARBIDES, ELECTRODES), (*TUNGSTEN COMPOUNDS, *ELECTROCHEMISTRY...CATALYSTS, TITANIUM COMPOUNDS, ZIRCONIUM COMPOUNDS, VANADIUM COMPOUNDS, NIOBIUM COMPOUNDS, TUNGSTEN COMPOUNDS, TANTALUM COMPOUNDS, MOLYBDENUM COMPOUNDS, SULFURIC ACID, CRYSTAL GROWTH, SODIUM COMPOUNDS

Onset of superconductivity in sodium and potassium intercalated molybdenum disulphide

NASA Technical Reports Server (NTRS)

Somoano, R. B.; Rembaum, A.

1971-01-01

Molybdenum disulfide in the form of natural crystals or powder has been intercalated at -65 to -70 C with sodium and potassium using the liquid ammonia technique. All intercalated samples were found to show a superconducting transition. A plot of the percent of diamagnetic throw versus temperature indicates the possible existence of two phases in the potassium intercalated molybdenum disulfide. The onset of superconductivity in potassium and sodium intercalated molybdenite powder was found to be approximately 6.2 and approximately 4.5 K, respectively. The observed superconductivity is believed to be due to an increase in electron density as a result of intercalation.

Genome sequences of Alicycliphilus denitrificans strain BC and K601(T)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oosterkamp, Margreet J.; Veuskens, Teun; Plugge, Caroline M.

2011-01-01

Alicycliphilus denitrificans strain BC and A. denitrificans strain K601T degrade cyclic hydrocarbons. These strains have been isolated from a mixture of wastewater treatment plant material and benzene-polluted soil and from a wastewater treatment plant, respectively, suggesting their role in bioremediation of soil and water. Although the strains are phylogenetically closely related, there are some clear physiological differences. The hydrocarbon cyclohexanol, for example, can be degraded by strain K601T but not by strain BC. Furthermore, both strains can use nitrate and oxygen as an electron acceptor, but only strain BC can use chlorate as electron acceptor. To better understand the nitratemore » and chlorate reduction mechanisms coupled to the oxidation of cyclic compounds, the genomes of A. denitrificans strains BC and K601T were sequenced. Here, we report the complete genome sequences of A. denitrificans strains BC and K601T.« less

Spectroscopic characterization of zinc oxide nanorods synthesized by solid-state reaction

NASA Astrophysics Data System (ADS)

Prasad, Virendra; D'Souza, Charlene; Yadav, Deepti; Shaikh, A. J.; Vigneshwaran, Nadanathangam

2006-09-01

Well-crystallized zinc oxide nanorods have been fabricated by single step solid-state reaction using zinc acetate and sodium hydroxide, at room temperature. The sodium lauryl sulfate (SLS) stabilized zinc oxide nanorods were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and photoluminescence spectroscopy. The X-ray diffraction revealed the wurtzite structure of zinc oxide. The size estimation by XRD and TEM confirmed that the ZnO nanorods are made of single crystals. The growth of zinc oxide crystals into rod shape was found to be closely related to its hexagonal nature. The mass ratio of SLS:ZnO in the nanorods was found to be 1:10 based on the thermogravimetric analysis. Blue shift of photoluminescence emission was noticed in the ZnO nanorods when compared to that of ZnO bulk. FT-IR analysis confirmed the binding of SLS with ZnO nanorods. Apart from ease of preparation, this method has the advantage of eco-friendliness since the solvent and other harmful chemicals were eliminated in the synthesis protocol.

Spray-dried chitosan/acid/NaCl microparticles enhance saltiness perception.

PubMed

Yi, Cheng; Tsai, Min-Lang; Liu, Tristan

2017-09-15

The composition, physicochemical properties and salinity of spray-dried chitosan/acid/NaCl microparticles were tested to ensure a low-sodium and high-salinity salty agent. The spray-dried chitosan/acid/NaCl microparticles were hollow and had a favourable hygroscopicity, and increased NaCl content and decreased organic acid content. Their size of the microparticles was 15.4-32.0μm and increased with NaCl concentration. The microparticles of acetic and lactic acid groups had a NaCl crystal size of 1-2 and 1-4μm, respectively. The NaCl crystals of acetic, lactic and citric acid group microparticles were distributed on the microparticle matrices, mostly on the microparticle surface and mainly on the inner walls of the microparticles walls, respectively. The acetic and lactic acid group microparticles were relatively smaller than general salt, with NaCl crystals distributed on the particle surfaces. Consequently, they were perceived as saltier than general salt and could potentially be regarded as a low-sodium salt for surface-salted foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environmentally safe oil-field reagents for development and operation of oil-gas deposits

NASA Astrophysics Data System (ADS)

Fakhreeva, A. V.; Manaure, D. A.; Dokichev, V. A.; Voloshin, A. I.; Telin, A. G.; Tomilov, Yu V.; Nifantiev, N. E.

2018-04-01

Sodium-carboxymethylcellulose and arabinogalactane inhibits the crystallization of calcium carbonate from a supersaturated aqueous solution at 80°C. The sizes of formed crystals CaCO3 in the presence of arabinogalactane, sodium-carboxymethylcellulose and neonol AF 9-10 decrease on an average 7-12 μm and a change of their structure. It is expected, that the mechanism of inhibitionis in specific adsorption polysaccharides and neonol on occurring crystalline surface of the calcium carbonate, both at the expense of electrostatic interaction of functional groups with Ca2+ ions, located on the surface of the crystal, and due to coordination and hydrogen bonds with oxygen atoms and HO-groups of additives. Oil-water emulsion rheology in the presence of neonol AF 9-10 has been studied. It is shown that neonol AF 9-10 decrease viscosity natural water-oil emulsion by 25 times. Addition of 5% neonol to water-oil emulsion leads to formation more than 20 stable emulsion forms of different density and composition. New highly effective “green” oilfield reagents have been developed on the basis of neonol and natural polysaccharides.

Promoted nitrogen dissolution due to the addition of Li or Ca to Ga-Na melt; some effects of additives on the growth of GaN single crystals using the sodium flux method

NASA Astrophysics Data System (ADS)

Morishita, Masanori; Kawamura, Fumio; Kawahara, Minoru; Yoshimura, Masashi; Mori, Yusuke; Sasaki, Takatomo

2005-10-01

The effect of the addition of Li or Ca to Ga-Na melt on the promotion of nitrogen dissolution was examined quantitatively in the growth of GaN single crystals using the sodium flux method. The addition of Li or Ca to Ga-Na melt increased both the solubility of solid GaN and that of gaseous nitrogen against the solution. The increase in the solubility of gaseous nitrogen seems to be caused by additives having a high binding energy with nitrogen. We measured the solubility of GaN and that of gaseous nitrogen against Ga-Na, Ga-Na-Li and Ga-Na-Ca melt in this study. On the basis of these data, we clarified the relationship between the N/Ga ratio in the solution and the coloration of GaN crystals grown in each system, and between changes in the yield of GaN and the absolute value of supersaturation.

Crystal structure of the true Nasicon: Na/sub 3/Zr/sub 2/Si/sub 2/PO/sub 12/

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boilot, J.P.; Collin, G.; Colomban, P.

For the first time, the results of single crystal determination of the true Nasicon are given. The structure refinement yielded the following composition: Na/sub 3.09(8)/Zr/sub 2.01(1)/P/sub 0.91/Si/sub 2.09/O/sub 12/. Evidence of the total occupancy of the Zr octahedron is found, displaying that only the Si/P non-stoichiometry mechanism is present in the Nasicon crystal. For the two temperatures which have been investigated (R.T. and 623K), the structures are very close to that of the Nasicon analog: Na/sub 3/Sc/sub 2/P/sub 3/O/sub 12/. However the Si/P substitution prevents the sodium long range ordering even in the monoclinic low temperature phase and therefore themore » cross over to the rhombohedral symmetry only involves very small atomic displacements. For both structures, a new sodium position (mid-Na) is displayed in the conduction channel, intermediate between the usual Na(1) and Na(2) sites.« less

Crystal growth and DFT insight on sodium para-nitrophenolate para-nitrophenol dihydrate single crystal for NLO applications

NASA Astrophysics Data System (ADS)

Selvakumar, S.; Boobalan, Maria Susai; Anthuvan Babu, S.; Ramalingam, S.; Leo Rajesh, A.

2016-12-01

Single crystals of sodium para-nitrophenolate para-nitrophenol dihydrate (SPPD) were grown by slow evaporation technique and its structure has been studied by FT-IR, FT-Raman and single crystal X-ray diffraction techniques. The optical and electrical properties were characterized by UV-Vis spectrum, and dielectric studies respectively. SPPD was thermally stable up to 128 °C as determined by TG-DTA curves. Using the Kurtz-Perry powder method, the second-harmonic generation efficiency was found to be five times to that of KDP. Third-order nonlinear response was studied using Z-scan technique with a He-Ne laser (632.8 nm) and NLO parameters such as intensity dependent refractive index, nonlinear absorption coefficient and third-order susceptibility were also estimated. The molecular geometry from X-ray experiment in the ground state has been compared using density functional theory (DFT) with appropriate basis set. The first-order hyperpolarizability also calculated using DFT approaches. Stability of the molecule arising from hyperconjugative interactions leading to its nonlinear optical activity and charge delocalization were analyzed using natural bond orbital technique. HOMO-LUMO energy gap value suggests the possibility of charge transfer within the molecule. Based on optimized ground state geometries, Natural bond orbital (NBO) analysis was performed to study donor-acceptor interactions.

Sodium Thiosulfate Prevents Chondrocyte Mineralization and Reduces the Severity of Murine Osteoarthritis

PubMed Central

Nasi, Sonia; Ea, Hang-Korng; Lioté, Frédéric; So, Alexander; Busso, Nathalie

2016-01-01

Objectives Calcium-containing crystals participate in the pathogenesis of OA. Sodium thiosulfate (STS) has been shown to be an effective treatment in calcification disorders such as calciphylaxis and vascular calcification. This study investigated the effects and mechanisms of action of STS in a murine model of OA and in chondrocyte calcification. Methods Hydroxyapatite (HA) crystals-stimulated murine chondrocytes and macrophages were treated with STS. Mineralization and cellular production of IL-6, MCP-1 and reactive oxygen species (ROS) were assayed. STS's effects on genes involved in calcification, inflammation and cartilage matrix degradation were studied by RT-PCR. STS was administered in the menisectomy model of murine OA, and the effect on periarticular calcific deposits and cartilage degeneration was investigated by micro-CT-scan and histology. Results In vitro, STS prevented in a dose-dependent manner calcium crystal deposition in chondrocytes and inhibited Annexin V gene expression. In addition, there was a reduction in crystal-induced IL-6 and MCP-1 production. STS also had an antioxidant effect, diminished HA-induced ROS generation and abrogated HA-induced catabolic responses in chondrocytes. In vivo, administration of STS reduced the histological severity of OA, by limiting the size of new periarticular calcific deposits and reducing the severity of cartilage damage. Conclusions STS reduces the severity of periarticular calcification and cartilage damage in an animal model of OA via its effects on chondrocyte mineralization and its attenuation of crystal-induced inflammation as well as catabolic enzymes and ROS generation. Our study suggests that STS may be a disease-modifying drug in crystal-associated OA. PMID:27391970

Sodium Thiosulfate Prevents Chondrocyte Mineralization and Reduces the Severity of Murine Osteoarthritis.

PubMed

Nasi, Sonia; Ea, Hang-Korng; Lioté, Frédéric; So, Alexander; Busso, Nathalie

2016-01-01

Calcium-containing crystals participate in the pathogenesis of OA. Sodium thiosulfate (STS) has been shown to be an effective treatment in calcification disorders such as calciphylaxis and vascular calcification. This study investigated the effects and mechanisms of action of STS in a murine model of OA and in chondrocyte calcification. Hydroxyapatite (HA) crystals-stimulated murine chondrocytes and macrophages were treated with STS. Mineralization and cellular production of IL-6, MCP-1 and reactive oxygen species (ROS) were assayed. STS's effects on genes involved in calcification, inflammation and cartilage matrix degradation were studied by RT-PCR. STS was administered in the menisectomy model of murine OA, and the effect on periarticular calcific deposits and cartilage degeneration was investigated by micro-CT-scan and histology. In vitro, STS prevented in a dose-dependent manner calcium crystal deposition in chondrocytes and inhibited Annexin V gene expression. In addition, there was a reduction in crystal-induced IL-6 and MCP-1 production. STS also had an antioxidant effect, diminished HA-induced ROS generation and abrogated HA-induced catabolic responses in chondrocytes. In vivo, administration of STS reduced the histological severity of OA, by limiting the size of new periarticular calcific deposits and reducing the severity of cartilage damage. STS reduces the severity of periarticular calcification and cartilage damage in an animal model of OA via its effects on chondrocyte mineralization and its attenuation of crystal-induced inflammation as well as catabolic enzymes and ROS generation. Our study suggests that STS may be a disease-modifying drug in crystal-associated OA.

Synthesis of mesoporous zeolite single crystals with cheap porogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tao Haixiang; Li Changlin; Ren Jiawen

2011-07-15

Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals have been successfully synthesized by adding soluble starch or sodium carboxymethyl cellulose (CMC) to a conventional zeolite synthesis system. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption analysis, {sup 27}Al magic angle spinning nuclear magnetic resonance ({sup 27}Al MAS NMR), temperature-programmed desorption of ammonia (NH{sub 3}-TPD) and ultraviolet-visible spectroscopy (UV-vis). The SEM images clearly show that all zeolite crystals possess the similar morphology with particle size of about 300 nm, the TEM images reveal that irregular intracrystalmore » pores are randomly distributed in the whole crystal. {sup 27}Al MAS NMR spectra indicate that nearly all of the Al atoms are in tetrahedral co-ordination in ZSM-5, UV-vis spectra confirm that nearly all of titanium atoms are incorporated into the framework of TS-1. The catalytic activity of meso-ZSM-5 in acetalization of cyclohexanone and meso-TS-1 in hydroxylation of phenol was also studied. The synthesis method reported in this paper is cost-effective and environmental friendly, can be easily expended to prepare other hierarchical structured zeolites. - Graphical abstract: Mesoporous zeolite single crystals were synthesized by using cheap porogens as template. Highlights: > Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals were synthesized. > Soluble starch or sodium carboxymethyl cellulose (CMC) was used as porogens. > The mesoporous zeolites had connected mesopores although closed pores existed. > Higher catalytic activities were obtained.« less

21 CFR 161.190 - Canned tuna.

Code of Federal Regulations, 2014 CFR

2014-04-01

... section. For the purpose of inhibiting the development of struvite crystals, sodium acid pyrophosphate may... section. Beginning with the top sieve, lift and drop each sieve by its open edge three times. Each time...

21 CFR 161.190 - Canned tuna.

Code of Federal Regulations, 2013 CFR

2013-04-01

... section. For the purpose of inhibiting the development of struvite crystals, sodium acid pyrophosphate may... section. Beginning with the top sieve, lift and drop each sieve by its open edge three times. Each time...

Proton-induced radioactivity in NaI (Tl) scintillation detectors

NASA Technical Reports Server (NTRS)

Fishman, G. J.

1977-01-01

Radioactivity induced by protons in sodium iodide scintillation crystals were calculated and directly measured. These data are useful in determining trapped radiation and cosmic-ray induced, background-counting rates in spaceborne detectors.

Cumulant Green's function calculations of plasmon satellites in bulk sodium: Influence of screening and the crystal environment

NASA Astrophysics Data System (ADS)

Zhou, Jianqiang Sky; Gatti, Matteo; Kas, J. J.; Rehr, J. J.; Reining, Lucia

2018-01-01

We present ab initio calculations of the photoemission spectra of bulk sodium using different flavors of the cumulant expansion approximation for the Green's function. In particular, we study the dispersion and intensity of the plasmon satellites. We show that the satellite spectrum is much more sensitive to many details than the quasiparticle spectrum, which suggests that the experimental investigation of satellites could yield additional information beyond the usual studies of the band structure. In particular, a comparison to the homogeneous electron gas shows that the satellites are influenced by the crystal environment, although the crystal potential in sodium is weak. Moreover, the temperature dependence of the lattice constant is reflected in the position of the satellites. Details of the screening also play an important role; in particular, the contribution of transitions from 2 s and 2 p semicore levels influences the satellites, but not the quasiparticle. Moreover, inclusion of contributions to the screening beyond the random-phase approximation has an effect on the satellites. Finally, we elucidate the importance of the coupling of electrons and holes by comparing the results of the time-ordered and the retarded cumulant expansion approximations. Again, we find small but noticeable differences. Since all the small effects add up, our most advanced calculation yields a satellite position which is improved with respect to previous calculations by almost 1 eV. This stresses the fact that the calculation of satellites is much more delicate than the calculation of a quasiparticle band structure.

Defense Small Business Innovation Research Program (SBIR). Abstracts of Phase II Awards. 1985.

DTIC Science & Technology

1985-01-01

SILICIDES : NEW SILICON COMPATIBLE ELECTRO-OPTIC MATERIALS TOPIC: 3 OFFICE: DARPA THE GOAL OF THIS WORK IS TO OBTAIN SINGLE CRYSTAL FILMS OF SEMI...CONSTITUENTS. CON- STITUENTS WITH IONIZATION POTENTIALS COMPARABLE TO THE WORK FUNCTION A ARE EVOLVED AS POSITIVE IONS (USUALLY SODIUM ATOMIC IONS FROM... SODIUM COMPOUND IMPURITIES). ARRIVAL OF A PARTICLE AT THE SURFACE CAUSES A BURST OF MANY IONS WHICH ARE DRAWN TO A NEARBY ION COLLECTOR ELECT- RODE

The use of moments of momentum to account for crystal habits

NASA Technical Reports Server (NTRS)

Barber, P. G.

1985-01-01

A three-step theory of crystal growth is proposed which involves first an association of molecules or ions in solution to form an impinging growth unit, then second the orientation of this unit prior to its impact on the surface of a crystal, and finally the attachment of this unit to the crystal face. From this theory the habit of a crystal is dependent upon the moments of momentum of the impinging growth unit. The results of sample calculations are presented or sodium chloride, succinic acid, sucrose, and chromium boride. The faces predicted by this proposed theory are compared with those predicted by other, energy-based calculations and with those experimentally observed. The proposed theory suggests alternative strategies for crystallization and habit modification which may be of technological importance. Listings of the two computer programs that were used are provided.

Binding of perlecan to transthyretin in vitro.

PubMed Central

Smeland, S; Kolset, S O; Lyon, M; Norum, K R; Blomhoff, R

1997-01-01

Transthyretin is one of two specific proteins involved in the transport of thyroid hormones in plasma; it possesses two binding sites for serum retinol-binding protein. In the present study we demonstrate that transthyretin also interacts in vitro with [35S]sulphate-labelled material from the medium of HepG2 cells. By using the same strategy as for purifying serum retinol-binding protein, [35S]sulphate-labelled medium was specifically eluted from a transthyretin-affinity column. Ion-exchange chromatography showed that the material was highly polyanionic, and its size and alkali susceptibility suggested that it was a proteoglycan. Structural analyses with chondroitinase ABC lyase and nitrous acid revealed that approx. 20% was chondroitin sulphate and 80% heparan sulphate. Immunoprecipitation showed that the [35S]sulphate-labelled material contained perlecan. Further analysis by binding studies revealed specific and saturable binding of 125I-transthyretin to perlecan-enriched Matrigel. Because inhibition of sulphation by treating HepG2 cells with sodium chlorate increased the affinity of the perlecan for transthyretin, and [3H]heparin was not retained by the transthyretin affinity column, the binding is probably mediated by the core protein and is not a protein-glycosaminoglycan interaction. Because perlecan is released from transthyretin in water, the binding might be due to hydrophobic interactions. PMID:9307034

Dimethyl sulfoxide reductase activity by anaerobically grown Escherichia coli HB101.

PubMed Central

Bilous, P T; Weiner, J H

1985-01-01

Escherichia coli grew anaerobically on a minimal medium with glycerol as the carbon and energy source and dimethyl sulfoxide (DMSO) as the terminal electron acceptor. DMSO reductase activity, measured with an artificial electron donor (reduced benzyl viologen), was preferentially associated with the membrane fraction (77 +/- 10% total cellular activity). A Km for DMSO reduction of 170 +/- 60 microM was determined for the membrane-bound activity. Methyl viologen, reduced flavin mononucleotide, and reduced flavin adenine dinucleotide also served as electron donors for DMSO reduction. Methionine sulfoxide, a DMSO analog, could substitute for DMSO in both the growth medium and in the benzyl viologen assay. DMSO reductase activity was present in cells grown anaerobically on DMSO but was repressed by the presence of nitrate or by aerobic growth. Anaerobic growth on DMSO coinduced nitrate, fumarate, and and trimethylamine-N-oxide reductase activities. The requirement of a molybdenum cofactor for DMSO reduction was suggested by the inhibition of growth and a 60% reduction in DMSO reductase activity in the presence of 10 mM sodium tungstate. Furthermore, chlorate-resistant mutants chlA, chlB, chlE, and chlG were unable to grow anaerobically on DMSO. DMSO reduction appears to be under the control of the fnr gene. PMID:3888958

21 CFR 161.190 - Canned tuna.

Code of Federal Regulations, 2011 CFR

2011-04-01

... section. For the purpose of inhibiting the development of struvite crystals, sodium acid pyrophosphate may... and drop each sieve by its open edge three times. Each time, the open edge of the sieve is lifted the...

21 CFR 161.190 - Canned tuna.

Code of Federal Regulations, 2012 CFR

2012-04-01

... section. For the purpose of inhibiting the development of struvite crystals, sodium acid pyrophosphate may... and drop each sieve by its open edge three times. Each time, the open edge of the sieve is lifted the...

Crystallization of calcium sulfate dihydrate in the presence of some metal ions

NASA Astrophysics Data System (ADS)

Hamdona, Samia K.; Al Hadad, Umaima A.

2007-02-01

Crystallization of calcium sulfate dihydrate (CaSO 4·2H 2O gypsum) in sodium chloride solutions in the presence of some metal ions, and over a range of relative super-saturation has been studied. The addition of metal ions, even at relatively low concentration (10 -6 mol l -1), markedly retard the rate of crystallization of gypsum. Retardation effect was enhanced with increase in the additives contents. Moreover, the effect was enhanced as the relative super-saturation decreases. Influence of mixed additives on the rate of crystallization (Cd 2++Arg, Cd 2++H 3PO 4 and Cd 2++PAA) has also been studied. Direct adsorption experiments of these metal ions on the surface of gypsum crystals have been made for comparison.

Mossbauer spectrometer radiation detector

NASA Technical Reports Server (NTRS)

Singh, J. J. (Inventor)

1973-01-01

A Mossbauer spectrometer with high efficiencies in both transmission and backscattering techniques is described. The device contains a sodium iodide crystal for detecting radiation caused by the Mossbauer effect, and two photomultipliers to collect the radiation detected by the crystal. When used in the transmission technique, the sample or scatterer is placed between the incident radiation source and the detector. When used in a backscattering technique, the detector is placed between the incident radiation source and the sample of scatterer such that the incident radiation will pass through a hole in the crystal and strike the sample. Diagrams of the instrument are provided.

49 CFR 173.54 - Forbidden explosives.

Code of Federal Regulations, 2013 CFR

2013-10-01

... subpart. (b) An explosive mixture or device containing a chlorate and also containing: (1) An ammonium... explosive. (d) Propellants that are unstable, condemned or deteriorated. (e) Nitroglycerin, diethylene... detonator. (h) Fireworks containing yellow or white phosphorus. (i) A toy torpedo, the maximum outside...

49 CFR 173.54 - Forbidden explosives.

Code of Federal Regulations, 2014 CFR

2014-10-01

... subpart. (b) An explosive mixture or device containing a chlorate and also containing: (1) An ammonium... explosive. (d) Propellants that are unstable, condemned or deteriorated. (e) Nitroglycerin, diethylene... detonator. (h) Fireworks containing yellow or white phosphorus. (i) A toy torpedo, the maximum outside...

Measuring Solvent Content of Macromolecular Crystals Using Fluorescence Recovery after Photobleaching

NASA Astrophysics Data System (ADS)

Siewny, Matthew; Kmetko, Jan

2010-10-01

We work out a novel protocol for measuring the solvent content (the fraction of crystal volume occupied by solvent) in biological crystals by the technique of fluorescence recovery after photobleaching (FRAP). Crystals of proteins with widely varying known solvent content (lysozyme, thaumatin, catalase, and ferritin) were grown in their native solution doped with sodium fluorescein dye and hydroxylamine (to prevent dye from binding to amine groups of the proteins.) The crystals were irradiated by a broadband, high intensity light through knife slits, leaving a rectangular area of bleached dye within the crystals. Measuring the flow of dye out of the bleached area allowed us to construct a curve relating the diffusion coefficient of dye to the channel size within the crystals, by solving the diffusion equation analytically. This curve may be used to measure the solvent content of any biological crystal in its native solution and help determine the number of proteins in the crystallographic asymmetric unit cell in x-ray structure solving procedures.

Synthesis and crystal structure analysis of uranyl triple acetates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klepov, Vladislav V., E-mail: vladislavklepov@gmail.com; Department of Chemistry, Samara National Research University, 443086 Samara; Serezhkina, Larisa B.

2016-12-15

Single crystals of triple acetates NaR[UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 3}·6H{sub 2}O (R=Mg, Co, Ni, Zn), well-known for their use as reagents for sodium determination, were grown from aqueous solutions and their structural and spectroscopic properties were studied. Crystal structures of the mentioned phases are based upon (Na[UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 3}){sup 2–} clusters and [R(H{sub 2}O){sub 6}]{sup 2+} aqua-complexes. The cooling of a single crystal of NaMg[UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 3}·6H{sub 2}O from 300 to 100 K leads to a phase transition from trigonal to monoclinic crystal system. Intermolecular interactions between the structural units and their mutual packing were studiedmore » and compared from the point of view of the stereoatomic model of crystal structures based on Voronoi-Dirichlet tessellation. Using this method we compared the crystal structures of the triple acetates with Na[UO{sub 2}(CH{sub 3}COO){sub 3}] and [R(H{sub 2}O){sub 6}][UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 2} and proposed reasons of triple acetates stability. Infrared and Raman spectra were collected and their bands were assigned. - Graphical abstract: Single crystals of uranium based triple acetates, analytical reagents for sodium determination, were synthesized and structurally, spectroscopically and topologically characterized. The structures were compared with the structures of compounds from preceding families [M(H{sub 2}O){sub 6})][UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 2} (M = Mg, Co, Ni, Zn) and Na[UO{sub 2}(CH{sub 3}COO){sub 3}]. Analysis was performed with the method of molecular Voronoi-Dirichlet polyhedra to reveal a large contribution of the hydrogen bonds into intermolecular interactions which can be a reason of low solubility of studied complexes.« less

Crystallization of Chicken Egg White Lysozyme from Assorted Sulfate Salts

NASA Technical Reports Server (NTRS)

Forsythe, Elizabeth L.; Snell, Edward H.; Malone, Christine C.; Pusey, Marc L.

1998-01-01

Chicken egg white lysozyme has been found to crystallize from ammonium, sodium, potassium, rubidium, magnesium, and manganese sulfates at acidic and basic pH, with protein concentrations from 60 to 190 mg/ml. Four different crystal morphologies have been obtained, depending upon the temperature, protein concentration, and precipitating salt employed, Crystals grown at 15 C were generally tetragonal, with space group P43212. Crystallization at 20 C typically resulted in the formation of orthorhombic crystals, space group P21212 1. The tetragonal much less than orthorhombic morphology transition appeared to be a function of both the temperature and protein concentration, occurring between 15 and 20 C and between 100 and 125 mg/ml protein concentration. Crystallization from 0.8 -1.2M magnesium sulfate at pH 7.6 - 8.0 gave a hexagonal (trigonal) crystal form, space group P3121, which diffracted to 2.8 A. Ammonium sulfate was also found to result in a monoclinic form, space group C2. Small twinned monoclinic crystals of approx. 0.2 mm on edge were grown by dialysis followed by seeded sitting drop crystallization.

Salt-Induced Physical Weathering of Stone

NASA Astrophysics Data System (ADS)

Schiro, M.; Ruiz-Agudo, E.; Rodriguez-Navarro, C.

2010-12-01

Salt weathering is recognized as an important mechanism that contributes to the modeling and shaping of the earth’s surface, in a range of environments spanning from the Sahara desert to Antarctica. It also contributes to the degradation and loss of cultural heritage, particularly carved stone and historic buildings. Soluble salts have recently been suggested to contribute to the shaping of rock outcrops on Mars and are being identified in other planetary bodies such as the moons of Jupiter (Europa and IO)1. Soluble salts such as sulfates, nitrates, chlorides and carbonates of alkali and alkali earth metals can crystallize within the porous system of rocks and building stones, exerting sufficient pressure against the pore walls to fracture the substrate. This physical damage results in increased porosity, thus providing a higher surface area for salt-enhanced chemical weathering. To better understand how salt-induced physical weathering occurs, we have studied the crystallization of the particularly damaging salt, sodium sulfate2, in a model system (a sintered porous glass of controlled porosity and pore size). For this elusive task of studying sub-surface crystallization in pores, we combined a variety of instruments to identify which phases crystallized during evaporation and calculated the supersaturation and associated crystallization pressure that caused damage. The heat of crystallization was measured using differential scanning calorimetry (DSC), providing the timing of crystallization events and phase transitions3, while the evaporation rate was recorded using thermal gravimetry (TG). These methods enabled calculation of the sodium sulfate concentration in solution at every point during evaporation. Two-dimensional X-ray diffraction (2D-XRD) performs synchrotron-like experiments in a normal lab by using a Molybdenum X-ray source (more than 5 times more penetrative than conventional Copper source). Using this method, we determined that the first phase to form within our porous system was the metastable heptahydrate (NaSO4●7H2O)4, followed by mirabilite (NaSO4●10H2O), and finally thenardite (NaSO4). Combining this sequence with data from TG/DSC, we calculated the supersaturation of the solution with respect to each crystallizing phase as well as the associated crystallization pressure5. In situ environmental scanning electron microscopy (ESEM) complemented 2D-XRD data by giving high magnification images of crystallization and phase transitions during dissolution/precipitation cycles. These results give us a clear understanding of sodium sulfate behavior during evaporative crystallization. Further studies will examine different salts and different substrates. This research will help us to better understand the crystallization of salts and associated weathering in cultural heritage, natural environments and possibly, in other planetary bodies. [1] Rodriguez-Navarro, C. (1998) Geophys. Res. Lett., 25, 3249-3252. [2] Rodriguez-Navarro, C., et al. (2000), Cement Concrete Res., 30, 1527-1534. [3] Espinosa, R., Scherer, G., (2008), Environ. Geol., 56, 605-621. [4] Hamilton, A., Hall, C., (2008), J. Anal. Atom. Spectrom., 23, 840-844. [5] Steiger, M., Asmussen, S., (2008), Geochim. Cosmochim. Acta, 72, 4291-4306.

Maximum Oxygen Content of Flowing Eutectic NaK in a Stainless Steel System.

DTIC Science & Technology

EUTECTICS, ALKALI METAL ALLOYS), (*LIQUID METALS, OXYGEN), (*POTASSIUM ALLOYS, SODIUM ALLOYS), LIQUID METAL PUMPS , FLUID FLOW, CONCENTRATION...CHEMISTRY), HIGH TEMPERATURE, FLOWMETERS, STAINLESS STEEL, ELECTROMAGNETIC PUMPS , TEMPERATURE, SAMPLING, LIQUID METAL COOLANTS, OXIDES, CRYSTALLIZATION.

Complex magnetic differentiation of cobalts in Na x CoO2 with 22 K Néel temperature

NASA Astrophysics Data System (ADS)

Mukhamedshin, I. R.; Gilmutdinov, I. F.; Salosin, M. A.; Alloul, H.

2014-06-01

Single crystals of sodium cobaltates Na x CoO2 with x ≈ 0.8 were grown by the floating zone technique. Using electrochemical Na de-intercalation method we reduced the sodium content in the as-grown crystals down to pure phase with 22 K Néel temperature and x ≈ 0.77. The 59Co NMR study in the paramagnetic state of the T N = 22 K phase permitted us to evidence that at least 6 Co sites are differentiated. They could be separated by their magnetic behavior into three types: a single site with cobalt close to non-magnetic Co3+, two sites with the most magnetic cobalts in the system, and the remaining three sites displaying an intermediate behavior. This unusual magnetic differentiation calls for more detailed NMR experiments on our well characterized samples.

Effect of silk sericin on morphology and structure of calcium carbonate crystal

NASA Astrophysics Data System (ADS)

Zhao, Rui-Bo; Han, Hua-Feng; Ding, Shao; Li, Ze-Hao; Kong, Xiang-Dong

2013-06-01

In this paper, silk sericin was employed to regulate the mineralization of calcium carbonate (CaCO3). CaCO3 composite particles were prepared by the precipitation reaction of sodium carbonate with calcium chloride solution in the presence of silk sericin. The as-prepared samples were collected at different reaction time to study the crystallization process of CaCO3 by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The results showed that silk sericin significantly affected the morphology and crystallographic polymorph of CaCO3. With increasing the reaction time, the crystal phase of CaCO3 transferred from calcite dominated to vaterite dominated mixtures, while the morphology of CaCO3 changed from disk-like calcite crystal to spherical vaterite crystal. These studies showed the potential of silk sericin used as a template molecule to control the growth of inorganic crystal.

Mechanisms of action of ligands of potential-dependent sodium channels.

PubMed

Tikhonov, D B

2008-06-01

Potential-dependent sodium channels play a leading role in generating action potentials in excitable cells. Sodium channels are the site of action of a variety of modulator ligands. Despite numerous studies, the mechanisms of action of many modulators remain incompletely understood. The main reason that many important questions cannot be resolved is that there is a lack of precise data on the structures of the channels themselves. Structurally, potential-dependent sodium channels are members of the P-loop channel superfamily, which also include potassium and calcium channels and glutamate receptor channels. Crystallization of a series of potassium channels showed that it was possible to analyze the structures of different members of the superfamily using the "homologous modeling" method. The present study addresses model investigations of the actions of ligands of sodium channels, including tetrodotoxin and batrachotoxin, as well as local anesthetics. Comparison of experimental data on sodium channel ligands with x-ray analysis data allowed us to reach a new level of understanding of the mechanisms of channel modulation and to propose a series of experimentally verifiable hypotheses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ben Smida, Youssef; Marzouki, Riadh; Georges, Samuel

A new sodium cobalt (II) arsenate Na{sub 4}Co{sub 7}(AsO{sub 4}){sub 6} has been synthesized by a solid-state reaction and its crystal structure determined from single crystal X-ray diffraction data. It crystallizes in the monoclinic system, space group C2/m, with a=10.7098(9) Å, b=14.7837(9) Å, c=6.6845(7) Å, and β=105.545(9)°. The structure is described as a three-dimensional framework built up of corner-edge sharing CoO{sub 6}, CoO{sub 4} and AsO{sub 4} polyhedra, with interconnecting channels along [100] in which the Na{sup +} cations are located. The densest ceramics with relative density of 94% was obtained by ball milling and optimization of sintering temperature, andmore » its microstructure characterized by scanning electron microscopy. The electrical properties of the ceramics were studied over a temperature interval from 280 °C to 560 °C using the complex impedance spectroscopy over the range of 13 MHz–5 Hz. The ionic bulk conductivity value of the sample at 360 °C is 2.51 10{sup −5} S cm{sup −1} and the measured activation energy is Ea=1 eV. The sodium migration pathways in the crystal structure were investigated computationally using the bond valence site energy (BVSE) model and classical molecular dynamics (MD) simulations. - Graphical abstract: Correlation between crystal structure, microstructure and ionic conductivity . Display Omitted - Highlights: • A new arsenate Na{sub 4}Co{sub 7}(AsO{sub 4}){sub 6} was prepared by solid state reaction. • Its crystal structure was determined by powder X-ray diffraction. • Na{sup +} ionic conductivity was probed by complex impedance spectroscopy. • Na{sup +} conduction pathways were modeled by bond-valence method and molecular dynamics.« less

Removal of Perchlorate and Chlorate in Aquatic SystemsUsing Integrated Technologies

EPA Science Inventory

Because of its extremely low concentrations and strong resistance to most treatment technologies, perchlorate has become one of the biggest challenges currently being faced by the drinking water industry. Few studies have looked at electrochemical reduction of aqueous perchlorate...

Modification of Sodium Release Using Porous Corn Starch and Lipoproteic Matrix.

PubMed

Christina, Josephine; Lee, Youngsoo

2016-04-01

Excessive sodium consumption can result in hypertension, diabetes, heart diseases, stroke, and kidney diseases. Various chips and extruded snacks, where salt is mainly applied on the product surface, accounted for almost 56% of snacks retail sales in 2010. Hence, it is important to target sodium reduction for those snack products. Past studies had shown that modifying the rate-release mechanism of sodium is a promising strategy for sodium reduction in the food industry. Encapsulation of salt can be a possible technique to control sodium release rate. Porous corn starch (PCS), created by enzymatic treatment and spray drying and lipoproteic matrix, created by gelation and freeze drying, were evaluated as carriers for controlled sodium release targeting topically applied salts. Both carriers encapsulated salt and their in vitro sodium release profiles were measured using a conductivity meter. The sodium release profiles of PCS treated with different enzymatic reaction times were not significantly different. Protein content and fat content altered sodium release profile from the lipoproteic matrix. The SEM images of PCS showed that most of the salt crystals coated the starch instead of being encapsulated in the pores while the SEM images and computed tomography scan of lipoproteic matrix showed salt dispersed throughout the matrix. Hence, PCS was found to have limitations as a sodium carrier as it could not effectively encapsulate salt inside its pores. The lipoproteic matrix was found to have a potential as a sodium carrier as it could effectively encapsulate salt and modify the sodium release profile. © 2016 Institute of Food Technologists®

METAL PHTHALOCYANINES

DOEpatents

Frigerio, N.A.

1962-03-27

A process is given for preparing heavy metal phthalocyanines, sulfonated or not. The process comprises mixing an inorganic metal salt with dimethyl formamide or methyl sulfoxide; separating the metal complex formed from the solution; mixing the complex with an equimolar amount of sodium, potassium, lithium, magnesium, or beryllium sulfonated or unsulfonated phthalocyanine whereby heavy-metal phthalocyanine crystals are formed; and separating the crystals from the solution. Uranyl, thorium, lead, hafnium, and lanthanide rare earth phthalocyanines can be produced by the process. (AEC)

PHOTON STUDY WITH SPUTNIK III

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chudakov, A.E.

1961-01-01

>A scintillation counter with twice the efficiency of a Geiger counter for photon recording was placed in the third Soviet satellite. The counter consisted of a cylindrical crystal of sodium iodide and a photomuitiplier. It was found that the total ionization in the crystal was much greater than expected. This excess seemed to depend on geomagnetic longitude as well as latitude. The most probable explanation is the bremsstrahlung radiation of electrons of energy less than 100 kev. (L.N.N.)

A{sub 5}RE{sub 4}X[TO{sub 4}]{sub 4} crystal growth: Fluoride flux synthesis of Na{sub 5}Ln{sub 4}F[GeO{sub 4}]{sub 4} (Ln=Pr, Nd), the first quaternary germanate oxyfluorides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Latshaw, Allison M.; Wilkins, Branford O.; Morrison, Gregory

Crystals of Na{sub 5}Pr{sub 4}F[GeO{sub 4}]{sub 4} and Na{sub 5}Nd{sub 4}F[GeO{sub 4}]{sub 4} were synthesized using a eutectic sodium fluoride, sodium chloride flux. Both compounds crystallize in the tetragonal space group I-4 with lattice parameters of a=12.1173(4) Å and c=5.6795(2) Å (Pr) and of a=12.0642(17) Å and c=5.6674(11) Å (Nd). The structure of the reported compounds is three-dimensional with face and corner sharing lanthanide polyhedra which edge and corner share with isolated germanium tetrahedra. These novel compositions represent the first example of quaternary germanium containing oxyfluorides. - Graphical abstract: Structural image of the first examples of quaternary germanate oxyfluorides. Displaymore » Omitted - Highlights: • Molten flux growth of crystals of two lanthanide germanate oxyfluorides. • Expansion of the A{sub 5}RE{sub 4}X[TO{sub 4}]{sub 4} family into germanate oxyfluorides. • Synthesis of Na{sub 5}Nd{sub 4}F[GeO{sub 4}]{sub 4} and Na{sub 5}Pr{sub 4}F[GeO{sub 4}]{sub 4}.« less

Sodium Sulfate Separation from Aqueous Alkaline Solutions via Crystalline Urea-Functionalized Capsules: Thermodynamics and Kinetics of Crystallization

DOE PAGES

Custelcean, Radu; Sloop, Frederick V.; Rajbanshi, Arbin; ...

2014-12-04

We measured the thermodynamics and kinetics of crystallization of sodium sulfate with a tripodal tris-urea receptor (L1) from aqueous alkaline solutions in the 15 55 C temperature range, with the goal of identifying the optimal conditions for efficient and quick sulfate removal from nuclear wastes. The use of radiolabeled Na 2 35SO 4 provided a practical way to monitor the sulfate concentration in solution by liquid scintillation counting. Our results are consistent with a two-step crystallization mechanism, involving relatively quick dissolution of crystalline L1 followed by the rate-limiting crystallization of the Na 2SO 4(L1) 2(H 2O) 4 capsules. We foundmore » that temperature exerted relatively little influence over the equilibrium sulfate concentration, which ranged between 0.004 and 0.011 M. Moreover, this corresponds to 77 91% removal of sulfate from a solution containing 0.0475 M initial sulfate concentration, as found in a typical Hanford waste tank. The apparent pseudo-first-order rate constant for sulfate removal increased 20-fold from 15 to 55 C, corresponding to an activation energy of 14.1 kcal/mol. At the highest measured temperature of 55 C, 63% and 75% of sulfate was removed from solution within 8 h and 24 h, respectively.« less

Orthorhombic lysozyme crystallization at acidic pH values driven by phosphate binding.

PubMed

Plaza-Garrido, Marina; Salinas-Garcia, M Carmen; Camara-Artigas, Ana

2018-05-01

The structure of orthorhombic lysozyme has been obtained at 298 K and pH 4.5 using sodium chloride as the precipitant and in the presence of sodium phosphate at a concentration as low as 5 mM. Crystals belonging to space group P2 1 2 1 2 1 (unit-cell parameters a = 30, b = 56, c = 73 Å, α = β = γ = 90.00°) diffracted to a resolution higher than 1 Å, and the high quality of these crystals permitted the identification of a phosphate ion bound to Arg14 and His15. The binding of this ion produces long-range conformational changes affecting the loop containing Ser60-Asn74. The negatively charged phosphate ion shields the electrostatic repulsion of the positively charged arginine and histidine residues, resulting in higher stability of the phosphate-bound lysozyme. Additionally, a low-humidity orthorhombic variant was obtained at pH 4.5, and comparison with those previously obtained at pH 6.5 and 9.5 shows a 1.5 Å displacement of the fifth α-helix towards the active-site cavity, which might be relevant to protein function. Since lysozyme is broadly used as a model protein in studies related to protein crystallization and amyloid formation, these results indicate that the interaction of some anions must be considered when analysing experiments performed at acidic pH values.

Adsorption of poly(vinyl alcohol) from water to a hydrophobic surface: effects of molecular weight, degree of hydrolysis, salt, and temperature.

PubMed

Kozlov, Mikhail; McCarthy, Thomas J

2004-10-12

The adsorption of poly(vinyl alcohol) (PVOH) from aqueous solutions to a silicon-supported fluoroalkyl monolayer is described. Thickness, wettability, and roughness of adsorbed films are studied as a function of polymer molecular weight, degree of hydrolysis (from the precursor, poly(vinyl acetate)), polymer concentration, salt type and concentration, and temperature. The data suggest a two-stage process for adsorption of the polymer: physisorption due to a hydrophobic effect (decrease in interfacial free energy) and subsequent stabilization of the adsorbed layer due to crystallization of the polymer. Adsorption of lower-molecular-weight polymers results in thicker films than those prepared with a higher molecular weight; this is ascribed to better crystallization of more mobile short chains. Higher contents of unhydrolyzed acetate groups on the poly(vinyl alcohol) chain lead to thicker adsorbed films. Residual acetate groups partition to the outermost surface of the films and determine wettability. Salts, including sodium chloride and sodium sulfate, promote adsorption, which results in thicker films; at the same time, their presence over a wide concentration range leads to formation of rough coatings. Sodium thiocyanate has little effect on PVOH adsorption, only slightly reducing the thickness in a 2 M salt solution. Increased temperature promotes adsorption in the presence of salt, but has little effect on salt-free solutions. Evidently, higher temperatures favor adsorption but cause crystallization to be less thermodynamically favorable. These competing effects result in the smoothest coatings being formed in an intermediate temperature range. Copyright 2004 American Chemical Society

Disinfection by-products of chlorine dioxide (chlorite, chlorate, and trihalomethanes): Occurrence in drinking water in Qatar.

PubMed

Al-Otoum, Fatima; Al-Ghouti, Mohammad A; Ahmed, Talaat A; Abu-Dieyeh, Mohammed; Ali, Mohammed

2016-12-01

The occurrence of chlorine dioxide (ClO 2 ) disinfection by-products (DBPs) in drinking water, namely, chlorite, chlorate, and trihalomethanes (THMs), was investigated. Two-hundred-ninety-four drinking water samples were collected from seven desalination plants (DPs), four reservoirs (R), and eight mosques (M) distributed within various locations in southern and northern Qatar. The ClO 2 concentration levels ranged from 0.38 to <0.02 mg L -1 , with mean values of 0.17, 0.12, and 0.04 mg L -1 for the DPs, Rs, and Ms, respectively. The chlorite levels varied from 13 μg L -1 to 440 μg L -1 , with median values varying from 13 to 230 μg L -1 , 77-320 μg L -1 , and 85-440 μg L -1 for the DPs, Rs, and Ms, respectively. The chlorate levels varied from 11 μg L -1 to 280 μg L -1 , with mean values varying from 36 to 280 μg L -1 , 11-200 μg L -1 , and 11-150 μg L -1 in the DPs, Rs, and Ms, respectively. The average concentration of THMs was 5 μg L -1 , and the maximum value reached 77 μg L -1 However, all of the DBP concentrations fell within the range of the regulatory limits set by GSO 149/2009, the World Health Organization (WHO), and Kahramaa (KM). Copyright © 2016 Elsevier Ltd. All rights reserved.

The location of dissimilatory nitrite reductase and the control of dissimilatory nitrate reductase by oxygen in Paracoccus denitrificans.

PubMed Central

Alefounder, P R; Ferguson, S J

1980-01-01

1. A method is described for preparing spheroplasts from Paracoccus denitrificans that are substantially depleted of dissimilatory nitrate reductase (cytochrome cd) activity. Treatment of cells with lysozyme + EDTA together with a mild osmotic shock, followed by centrifugation, yielded a pellet of spheroplasts and a supernatant that contained d-type cytochrome. The spheroplasts were judged to have retained an intact plasma membrane on the basis that less than 1% of the activity of a cytoplasmic marker protein, malate dehydrogenase, was released from the spheroplasts. In addition to a low activity towards added nitrite, the suspension of spheroplasts accumulated the nitrite that was produced by respiratory chain-linked reduction of nitrate. It is concluded that nitrate reduction occurs at the periplasmic side of the plasma membrane irrespective of whether nitrite is generated by nitrate reduction or is added exogenously. 2. Further evidence for the integrity of the spheroplasts was that nitrate reduction was inhibited by O2, and that chlorate was reduced at a markedly lower rate than nitrate. These data are taken as evidence for an intact plasma membrane because it was shown that cells acquire the capability to reduce nitrate under aerobic conditions after addition of low amounts of Triton X-100 which, with the same titre, also overcame the permeability barrier to chlorate reduction by intact cells. The close relationship between the appearance of chlorate reduction and the loss of the inhibitory effect of O2 on nitrate reduction also suggests that the later feature of nitrate respiration is due to a control on the accessibility of nitrate to its reductase rather than on the flow of electrons to nitrate reductase. PMID:7197918

High-affinity nitrate/nitrite transporters NrtA and NrtB of Aspergillus nidulans exhibit high specificity and different inhibitor sensitivity

PubMed Central

Akhtar, Naureen; Karabika, Eugenia; Kinghorn, James R.; Glass, Anthony D.M.; Unkles, Shiela E.

2015-01-01

The NrtA and NrtB nitrate transporters are paralogous members of the major facilitator superfamily in Aspergillus nidulans. The availability of loss-of-function mutations allowed individual investigation of the specificity and inhibitor sensitivity of both NrtA and NrtB. In this study, growth response tests were carried out at a growth-limiting concentration of nitrate (1 mM) as the sole nitrogen source, in the presence of a number of potential nitrate analogues at various concentrations, to evaluate their effect on nitrate transport. Both chlorate and chlorite inhibited fungal growth, with chlorite exerting the greater inhibition. The main transporter of nitrate, NrtA, proved to be more sensitive to chlorate than the minor transporter, NrtB. Similarly, the cation caesium was shown to exert differential effects, strongly inhibiting the activity of NrtB, but not NrtA. In contrast, no inhibition of nitrate uptake by NrtA or NrtB transporters was observed in either growth tests or uptake assays in the presence of bicarbonate, formate, malonate or oxalate (sulphite could not be tested in uptake assays owing to its reaction with nitrate), indicating significant specificity of nitrate transport. Kinetic analyses of nitrate uptake revealed that both chlorate and chlorite inhibited NrtA competitively, while these same inhibitors inhibited NrtB in a non-competitive fashion. The caesium ion appeared to inhibit NrtA in a non-competitive fashion, while NrtB was inhibited uncompetitively. The results provide further evidence of the distinctly different characteristics as well as the high specificity of nitrate uptake by these two transporters. PMID:25855763

Crystallization and preliminary X-ray diffraction studies of θ-toxin (perfringolysin O), a pore-forming cytolysin of Clostridium perfringens

NASA Astrophysics Data System (ADS)

Sugahara, Mitsuaki; Sekino-Suzuki, Naoko; Ohno-Iwashita, Yoshiko; Miki, Kunio

1996-10-01

θ-Toxin (perfringolysin O), a cholesterol-binding, pore-forming cytolysin of Clostridium perfringens type A was crystallized by the vapor diffusion procedure using polyethyleneglycol 4000 and sodium chloride as precipitants in 2-(cyclohexylamino)ethanesulfonic acid (CHES) buffer at pH 9.5. The diffraction patterns of precession photographs indicated that the crystals belong to the orthorhombic system and the space group C222 1 with unit-cell dimensions of a = 47.7 Å, b = 182.0 Å and c = 175.8 Å. Assuming that the asymmetric unit contains one or two molecules (Mw 52 700), the Vm value is calculated as 3.6 or 1.8 Å 3/dalton, respectively. The crystals diffract X-rays to at least 3 Å resolution and are suitable for high resolution X-ray crystal structure determination.

Crystallization and preliminary X-ray analysis of copper amine oxidase from Escherichia coli K-12.

PubMed

Roh, J H; Suzuki, H; Kumagai, H; Yamashita, M; Azakami, H; Murooka, Y; Mikami, B

1994-05-13

Copper-containing monoamine oxidase (MAO) from Escherichia coli was overproduced in the periplasmic space by expression of the cloned gene. The purified MAO has been crystallized by means of the hanging drop technique using sodium citrate as a precipitant. The crystals belong to the orthorhombic system, space group P2(1)2(1)2(1), with unit cell dimensions of a = 136.1 A, b = 168.4 A and c = 81.6 A. The asymmetric unit contains one molecule of MAO, with a crystal volume per protein mass (Vm) of 2.88 A3/Da and a solvent content of 58% by volume. The crystals diffract X-rays to a resolution limit of at least 2.7 A and are resistant to X-ray radiation damage. They appear to be suitable for X-ray structure analysis.

The Preparation and Characterization of a Sodium Tungsten Bronze

ERIC Educational Resources Information Center

Conroy, Lawrence E.

1977-01-01

Describes an experiment that utilizes the techniques of temperature synthesis, crystallization from a molten salt, oxidation-reduction in a molten salt, powder X-ray diffraction and analysis by high temperature volatilization or a specific ion electrode. (MLH)

Two-Dimensional Magnesium Phosphate Nanosheets Form Highly Thixotropic Gels That Up-Regulate Bone Formation.

PubMed

Laurenti, Marco; Al Subaie, Ahmed; Abdallah, Mohamed-Nur; Cortes, Arthur R G; Ackerman, Jerome L; Vali, Hojatollah; Basu, Kaustuv; Zhang, Yu Ling; Murshed, Monzur; Strandman, Satu; Zhu, Julian; Makhoul, Nicholas; Barralet, Jake E; Tamimi, Faleh

2016-08-10

Hydrogels composed of two-dimensional (2D) nanomaterials have become an important alternative to replace traditional inorganic scaffolds for tissue engineering. Here, we describe a novel nanocrystalline material with 2D morphology that was synthesized by tuning the crystallization of the sodium-magnesium-phosphate system. We discovered that the sodium ion can regulate the precipitation of magnesium phosphate by interacting with the crystal's surface causing a preferential crystal growth that results in 2D morphology. The 2D nanomaterial gave rise to a physical hydrogel that presented extreme thixotropy, injectability, biocompatibility, bioresorption, and long-term stability. The nanocrystalline material was characterized in vitro and in vivo and we discovered that it presented unique biological properties. Magnesium phosphate nanosheets accelerated bone healing and osseointegration by enhancing collagen formation, osteoblasts differentiation, and osteoclasts proliferation through up-regulation of COL1A1, RunX2, ALP, OCN, and OPN. In summary, the 2D magnesium phosphate nanosheets could bring a paradigm shift in the field of minimally invasive orthopedic and craniofacial interventions because it is the only material available that can be injected through high gauge needles into bone defects in order to accelerate bone healing and osseointegration.

Continuous structural evolution of calcium carbonate particles: a unifying model of copolymer-mediated crystallization.

PubMed

Kulak, Alex N; Iddon, Peter; Li, Yuting; Armes, Steven P; Cölfen, Helmut; Paris, Oskar; Wilson, Rory M; Meldrum, Fiona C

2007-03-28

Two double-hydrophilic block copolymers, each comprising a nonionic block and an anionic block comprising pendent aromatic sulfonate groups, were used as additives to modify the crystallization of CaCO3. Marked morphological changes in the CaCO3 particles were observed depending on the reaction conditions used. A poly(ethylene oxide)-b-poly(sodium 4-styrenesulfonate) diblock copolymer was particularly versatile in effecting a morphological change in calcite particles, and a continuous structural transition in the product particles from polycrystalline to mesocrystal to single crystal was observed with variation in the calcium concentration. The existence of this structural sequence provides unique insight into the mechanism of polymer-mediated crystallization. We propose that it reflects continuity in the crystallization mechanism itself, spanning the limits from nonoriented aggregation of nanoparticles to classical ion-by-ion growth. The various pathways to polycrystalline, mesocrystal, and single-crystal particles, which had previously been considered to be distinct, therefore all form part of a unifying crystallization framework based on the aggregation of precursor subunits.

Laboratory experiments on simultaneous removal of K and P from synthetic and real urine for nutrient recycle by crystallization of magnesium-potassium-phosphate-hexahydrate in a draft tube and baffle reactor.

PubMed

Xu, Kangning; Wang, Chengwen; Wang, Xiaoxue; Qian, Yi

2012-06-01

The simultaneous removal of K and P from urine for nutrient recycling by crystallization of magnesium potassium phosphate hexahydrate (MPP) in a laboratory-scale draft tube and baffle reactor (DTBR) is investigated. Results show that mixing speed and hydraulic retention time are important operating factors that influence crystallization and crystal settlement. Slurry should be discharged at a crystal retention time of 11 h to maintain fluidity in the reactor. Further applications of the DTBR using real urine (pretreated by ammonia stripping and diluted five times) showed that 76% K and 68% P were recycled to multi-nutrient products. The crystals collected were characterized and confirmed mainly as a mixture of magnesium ammonium phosphate hexahydrate, MPP, and magnesium sodium phosphate heptahydrate. Results indicate that the DTBR effectively achieved the simultaneous recycling of K and P from urine to multi-nutrient products through MPP crystallization. Copyright © 2012 Elsevier Ltd. All rights reserved.

Heterologous expression, purification, crystallization and preliminary X-ray analysis of raucaffricine glucosidase, a plant enzyme specifically involved in Rauvolfia alkaloid biosynthesis.

PubMed

Ruppert, Martin; Panjikar, Santosh; Barleben, Leif; Stöckigt, Joachim

2006-03-01

Raucaffricine glucosidase (RG) is an enzyme that is specifically involved in the biosynthesis of indole alkaloids from the plant Rauvolfia serpentina. After heterologous expression in Escherichia coli cells, crystals of RG were obtained by the hanging-drop vapour-diffusion technique at 293 K with 0.3 M ammonium sulfate, 0.1 M sodium acetate pH 4.6 buffer and 11% PEG 4000 as precipitant. Crystals belong to space group I222 and diffract to 2.30 A, with unit-cell parameters a = 102.8, b = 127.3, c = 215.8 A.

Influence of sodium borate on the early age hydration of calcium sulfoaluminate cement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Champenois, Jean-Baptiste; Dhoury, Mélanie; Cau Dit Coumes, Céline, E-mail: celine.cau-dit-coumes@cea.fr

Calcium sulfoaluminate (CSA) cements are potential candidates for the conditioning of radioactive wastes with high sodium borate concentrations. This work thus investigates early age hydration of two CSA cements with different gypsum contents (0 to 20%) as a function of the mixing solution composition (borate and NaOH concentrations). Gypsum plays a key role in controlling the reactivity of cement. When the mixing solution is pure water, increasing the gypsum concentration accelerates cement hydration. However, the reverse is observed when the mixing solution contains sodium borate. Until gypsum exhaustion, the pore solution pH remains constant at ~ 10.8, and a poorlymore » crystallized borate compound (ulexite) precipitates. A correlation is established between this transient precipitation and the hydration delay. Decreasing the gypsum content in the binder, or increasing the sodium content in the mixing solution, are two ways of reducing the stability of ulexite, thus decreasing the hydration delay.« less

FILTRATION OF SALT SMOKE FROM CHLORATE CANDLE OXYGEN.

DTIC Science & Technology

their associated equipment for use on submarines. Rockwool -wire mesh combinations were first used in welded assemblies which were cleaned by water...washing when they became clogged. The rockwool was later replaced with fiberglass blanket, and two modifications of the assembly were made, but the

The Detection of Evolved Oxygen from the Rocknest Eolian Bedform Material by the Sample Analysis at Mars(SAM) instrument at the Mars Curiosity Landing Site

NASA Technical Reports Server (NTRS)

Sutter, B.; Archer, D.; Ming, D.; Eigenbrode, J. L.; Franz, H.; Glavin, D. P.; McAdam, A.; Mahaffy, P.; Stern, J.; Navarro-Gonzalex, R.;

Continuous-wave sodium D2 resonance radiation generated in single-pass sum-frequency generation with periodically poled lithium niobate.

PubMed

Yue, J; She, C-Y; Williams, B P; Vance, J D; Acott, P E; Kawahara, T D

2009-04-01

With two cw single-mode Nd:YAG lasers at 1064 and 1319 nm and a periodically poled lithium niobate crystal, 11 mW of 2 kHz/100 ms bandwidth single-mode tunable 589 nm cw radiation has been detected using single-pass sum-frequency generation. The demonstrated conversion efficiency is approximately 3.2%[W(-1) cm(-1)]. This compact solid-state light source has been used in a solid-state-dye laser hybrid sodium fluorescence lidar transmitter to measure temperatures and winds in the upper atmosphere (80-105 km); it is being implemented into the transmitter of a mobile all-solid-state sodium temperature and wind lidar under construction.

A sodium gallophosphate with an original tunnel structure: NaGa 2(OH)(PO 4) 2

NASA Astrophysics Data System (ADS)

Guesdon, A.; Monnin, Y.; Raveau, B.

2003-05-01

A new sodium gallophosphate, NaGa 2(OH)(PO 4) 2, has been obtained by hydrothermal synthesis under autogeneous pressure at 473 K. It crystallizes in the P2 1/ n space group with the cell parameters a=8.9675(8) Å, b=8.9732(5) Å, c=9.2855(7) Å, β=114.812(6)°, V=678.2 Å 3 ( Z=4). In its original three-dimensional framework, monophosphate groups share their apices with [Ga 4O 16(OH) 2] tetrameric units, which are built from two GaO 5(OH) octahedra and two GaO 4(OH) trigonal bipyramids. The sodium cations are located in tunnels running along a, whereas the tunnels running along b are empty.

Concentrated aqueous sodium chloride solution in clays at thermodynamic conditions of hydraulic fracturing: Insight from molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Svoboda, Martin; Lísal, Martin

2018-06-01

To address a high salinity of flow-back water during hydraulic fracturing, we use molecular dynamics (MD) simulations and study the thermodynamics, structure, and diffusion of concentrated aqueous salt solution in clay nanopores. The concentrated solution results from the dissolution of a cubic NaCl nanocrystal, immersed in an aqueous NaCl solution of varying salt concentration and confined in clay pores of a width comparable to the crystal size. The size of the nanocrystal equals to about 18 Å which is above a critical nucleus size. We consider a typical shale gas reservoir condition of 365 K and 275 bar, and we represent the clay pores as pyrophyllite and Na-montmorillonite (Na-MMT) slits. We employ the Extended Simple Point Charge (SPC/E) model for water, Joung-Cheatham model for ions, and CLAYFF for the slit walls. We impose the pressure in the normal direction and the resulting slit width varies from about 20 to 25 Å when the salt concentration in the surrounding solution increased from zero to an oversaturated value. By varying the salt concentration, we observe two scenarios. First, the crystal dissolves and its dissolution time increases with increasing salt concentration. We describe the dissolution process in terms of the number of ions in the crystal, and the crystal size and shape. Second, when the salt concentration reaches a system solubility limit, the crystal grows and attains a new equilibrium size; the crystal comes into equilibrium with the surrounding saturated solution. After crystal dissolution, we carry out canonical MD simulations for the concentrated solution. We evaluate the hydration energy, density profiles, orientation distributions, hydrogen-bond network, radial distribution functions, and in-plane diffusion of water and ions to provide insight into the microscopic behaviour of the concentrated aqueous sodium chloride solution in interlayer galleries of the slightly hydrophobic pyrophyllite and hydrophilic Na-MMT pores.

Concentrated aqueous sodium chloride solution in clays at thermodynamic conditions of hydraulic fracturing: Insight from molecular dynamics simulations.

PubMed

Svoboda, Martin; Lísal, Martin

2018-06-14

To address a high salinity of flow-back water during hydraulic fracturing, we use molecular dynamics (MD) simulations and study the thermodynamics, structure, and diffusion of concentrated aqueous salt solution in clay nanopores. The concentrated solution results from the dissolution of a cubic NaCl nanocrystal, immersed in an aqueous NaCl solution of varying salt concentration and confined in clay pores of a width comparable to the crystal size. The size of the nanocrystal equals to about 18 Å which is above a critical nucleus size. We consider a typical shale gas reservoir condition of 365 K and 275 bar, and we represent the clay pores as pyrophyllite and Na-montmorillonite (Na-MMT) slits. We employ the Extended Simple Point Charge (SPC/E) model for water, Joung-Cheatham model for ions, and CLAYFF for the slit walls. We impose the pressure in the normal direction and the resulting slit width varies from about 20 to 25 Å when the salt concentration in the surrounding solution increased from zero to an oversaturated value. By varying the salt concentration, we observe two scenarios. First, the crystal dissolves and its dissolution time increases with increasing salt concentration. We describe the dissolution process in terms of the number of ions in the crystal, and the crystal size and shape. Second, when the salt concentration reaches a system solubility limit, the crystal grows and attains a new equilibrium size; the crystal comes into equilibrium with the surrounding saturated solution. After crystal dissolution, we carry out canonical MD simulations for the concentrated solution. We evaluate the hydration energy, density profiles, orientation distributions, hydrogen-bond network, radial distribution functions, and in-plane diffusion of water and ions to provide insight into the microscopic behaviour of the concentrated aqueous sodium chloride solution in interlayer galleries of the slightly hydrophobic pyrophyllite and hydrophilic Na-MMT pores.

Characterization of solar-grade silicon produced by the SiF4-Na process

NASA Technical Reports Server (NTRS)

Sanjurjo, A.; Sancier, K. M.; Emerson, R. M.; Leach, S. C.; Minahan, J.

1986-01-01

A process was developed for producing low cost solar grade silicon by the reaction between SiF4 gas and sodium metal. The results of the characterization of the silicon are presented. These results include impurity levels, electronic properties of the silicon after crystal growth, and the performance of solar photovoltaic cells fabricated from wafers of the single crystals. The efficiency of the solar cells fabricated from semiconductor silicon and SiF4-Na silicon was the same.

DISPOSITION OF THE INNER RADIATION BELT AND MAGNETIC FIELD OF THE EARTH

DOE Office of Scientific and Technical Information (OSTI.GOV)

GORCHAKOV, IE. V.

1963-02-01

A scintillation counter on Sputnik III was used to conduct ionization measurement in a sodium iodide crystal and register the number of events releasing more than 35 kev in the crystal. The boundary of the inner radiation belt shows a strong longitudinal effect. The observed dependence on longitude of the boundary was explained by the fact that the inner belt consists of particles captured by the geomagnetic field and constitutes a noncentral dipole field. (C.E.S.)

Studies of the Crystallization Process of Aluminum-Silicon Alloys Using a High Temperature Microscope. Thesis

NASA Technical Reports Server (NTRS)

Justi, S.

1985-01-01

It is shown that primary silicon crystals grow polyhedral in super-eutectic AlSi melts and that phosphorus additives to the melt confirm the strong seeding capacity. Primary silicon exhibits strong dendritic seeding effects in eutectic silicon phases of various silicon alloys, whereas primary aluminum does not possess this capacity. Sodium addition also produces a dendritic silicon network growth in the interior of the sample that is attributed to the slower silicon diffusion velocity during cooling.

Synthesis and structure of [Na11(OtBu)10(OH)]: 1H NMR shift of a hydroxide ion encapsulated in a 21-vertex alcoholate cage.

PubMed

Geier, Jens; Grützmacher, Hansjörg

2003-12-07

[Na11(OtBu)10(OH)], a hydroxide enclosing 21-vertex cage compound, was found to crystallize from mixtures of sodium tert.butanolate with sodium hydroxide. Its structure can be derived from the known (NaOtBu)6-hexaprismane by replacing one butanolate unit with OH- and capping the latter with five additional units of NaOtBu. The hydroxide shows a signal at -3.21 ppm in the 1H NMR spectrum.

Amorphous Formulation and in Vitro Performance Testing of Instantly Disintegrating Buccal Tablets for the Emergency Delivery of Naloxone.

PubMed

Alqurshi, Abdulmalik; Kumar, Zahrae; McDonald, Rebecca; Strang, John; Buanz, Asma; Ahmed, Shagufta; Allen, Elizabeth; Cameron, Peter; Rickard, James A; Sandhu, Verity; Holt, Chris; Stansfield, Rebecca; Taylor, David; Forbes, Ben; Royall, Paul G

2016-05-02

The aim of this study was to develop a freeze-dried buccal tablet for the rapid delivery of naloxone in opioid overdose. The tablet composition was optimized to produce an amorphous matrix, which was confirmed by the absence of peaks associated with crystallinity observed by differential scanning calorimetry and powder X-ray diffraction. Tablets with high gelatin content lacked adequate porosity. Mannitol was added to the formulation to bridge and intercalate gelatin's tight polymer aggregates, however sodium bicarbonate was also required to prevent crystallization within the tablets. A linear reduction in mannitol's recrystallization enthalpy was observed with increasing sodium bicarbonate concentration (ΔrecryH = -20.3[NaHCO3] + 220.9; r(2) = 0.9, n = 18). The minimum sodium bicarbonate concentration for full inhibition of mannitol crystallization was 10.9% w/w. Freeze-dried tablets with lower amounts of sodium bicarbonate possessed a crystalline fraction that PXRD identified as mannitol hemihydrate from the unique peak at 9.7° 2θ. Mannitol's greater affinity for both ions and residual water rather than its affinity for self-association was the mechanism for the inhibition of crystallization observed here. The optimized tablet (composition mannitol 24% w/w (4.26 mg), gelatin 65% w/w (11.7 mg), sodium bicarbonate 11% w/w (1.98 mg), and naloxone 800 μg) formed predominantly amorphous tablets that disintegrated in less than 10 s. Optimized tablets were chemically and physically stable over 9 months storage at 25 °C. As speed of drug liberation is the critical performance attribute for a solid dosage form designed to deliver drug in an emergency, a novel imaging based in vitro disintegration assay for buccal tablets was developed. The assay was optimized with regard to conditions in the buccal cavity: i.e., temperature 33-37 °C, volume of medium (0.1-0.7 mL), and use of mucin-containing biorelevant medium. The disintegration assay was sensitive to temperature, medium volume, and medium composition; naloxone tablet disintegration was extremely rapid, with full disintegration ranging from 5 to 20 s. In conclusion, rapidly disintegrating tablets have been developed which are suitable for proof-of-concept clinical trial in humans to determine the pharmacokinetics of naloxone delivered via the buccal route.

A 125Te and 23Na NMR investigation of the structure and crystallisation of sodium tellurite glasses.

PubMed

Holland, D; Bailey, J; Ward, G; Turner, B; Tierney, P; Dupree, R

2005-01-01

125Te static nuclear magnetic resonance (NMR) and 23Na and 125Te magic angle spinning (MAS) NMR have been used, in conjunction with X-ray diffraction, to examine the structure and crystallisation behaviour of glasses of composition xNa2O.(1-x)TeO2 (0.075 x 0.4). The MAS NMR 23Na spectra from the glasses are broad and featureless but shift by approximately +5 ppm with increased x, i.e. as the system becomes more ionic. The static 125Te NMR spectra show an increase in axial symmetry with increasing x, indicating a shift from predominantly [TeO4] to [TeO3] structural units. The 23Na and 125Te spectra from the crystallised samples have been fitted to obtain information on the sites in the metastable crystal phases, which are the first to form on heating and which are therefore more closely related to the glass structure than thermodynamically stable crystal phases. New sodium tellurite phases are reported, including a sodium stabilised, face centred cubic phase related to delta-TeO2; a metastable form of Na2Te4O9 containing 3 sodium and 4 tellurium sites; and a metastable form of Na2Te2O5 containing 2 sodium sites. There is evidence of oxidation of TeIV to TeVI occurring in glasses with high values of x and, at x=0.40 and 0.50 (outside the glass forming range), some sodium metatellurate (Na2TeO4) is formed at the same time as sodium metatellurite (Na2TeO3). The 125Te shift is very sensitive to environment within the sodium tellurite system, covering more than 320 ppm, with anisotropies varying from 640 to 1540 ppm. The lack of features in the 125Te spectra of the glass phases, combined with the large shift range and high but variable anisotropy, means than it is not possible to obtain a unique fit to any presumed species present. Furthermore, the chemical shift anisotropy parameters for three of the four Te sites in the Na2Te4O9 phase are found to lie outside the range used for previous simulations of glass spectra.

16 CFR 1507.2 - Prohibited chemicals.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Prohibited chemicals. 1507.2 Section 1507.2... FIREWORKS DEVICES § 1507.2 Prohibited chemicals. Fireworks devices shall not contain any of the following chemicals: (a) Arsenic sulfide, arsenates, or arsenites. (b) Boron. (c) Chlorates, except: (1) In colored...

16 CFR 1507.2 - Prohibited chemicals.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Prohibited chemicals. 1507.2 Section 1507.2... FIREWORKS DEVICES § 1507.2 Prohibited chemicals. Fireworks devices shall not contain any of the following chemicals: (a) Arsenic sulfide, arsenates, or arsenites. (b) Boron. (c) Chlorates, except: (1) In colored...

16 CFR 1507.2 - Prohibited chemicals.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Prohibited chemicals. 1507.2 Section 1507.2... FIREWORKS DEVICES § 1507.2 Prohibited chemicals. Fireworks devices shall not contain any of the following chemicals: (a) Arsenic sulfide, arsenates, or arsenites. (b) Boron. (c) Chlorates, except: (1) In colored...

16 CFR 1507.2 - Prohibited chemicals.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Prohibited chemicals. 1507.2 Section 1507.2... FIREWORKS DEVICES § 1507.2 Prohibited chemicals. Fireworks devices shall not contain any of the following chemicals: (a) Arsenic sulfide, arsenates, or arsenites. (b) Boron. (c) Chlorates, except: (1) In colored...

The influence of additives on the crystal habit of gibbsite

NASA Astrophysics Data System (ADS)

Seyssiecq, Isabelle; Veesler, Stéphane; Pèpe, Gérard; Boistelle, Roland

1999-01-01

Crystallization of gibbsite (Al(OH) 3) is an important stage of the Bayer process, production of alumina from bauxite ores. In both pure or industrial supersaturated sodium aluminate solutions, gibbsite crystals are always agglomerated. In the present paper, we present results of a study concerning the influence of different polycarboxylic acids as crystal habit modifier for gibbsite. In pure solution, agglomerated hexagonal plates are observed. Whereas acicular and tabular morphologies are found in the presence of different additives. These results are discussed referring to the crystallographic structure of gibbsite. It is found that only oxygen atoms are present on gibbsite surface. This observation leads us to propose an additive way of acting by formation of a molecular complex between the growth unit and the carboxylic groups of the additive.

Orientational disorder in sodium cadmium trifluoride trihydrate, NaCdF{sub 3}.3H{sub 2}O

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Robert W.; Mar, Arthur; Liu Jianjun

2006-03-09

Attempts to synthesize the hypothetical anhydrous fluoroperovskite NaCdF{sub 3}, which has been predicted to be stable, resulted instead in a hydrated fluoride of nominal composition NaCdF{sub 3}.3H{sub 2}O. It decomposes to sodium fluoride, cadmium fluoride, and water at 60deg. C. Its structure has been determined by single-crystal X-ray diffraction. Na{sub 0.92(2)}Cd{sub 1.08}F{sub 3.08}.2.92H{sub 2}O crystallizes in the cubic space group Fm3-bar m with a=8.2369(4)A and Z=4. The structure is based on the NaSbF{sub 6}-type (an ordered variant of the ReO{sub 3}-type) and features tilted sodium- and cadmium-centred octahedra that are linked by shared vertices to form a three-dimensional network. Substitutionalmore » disorder occurs on the nonmetal site, which is occupied by both F and O atoms, and on one of the metal sites, which is occupied by 92% Na and 8% Cd. A four-fold orientational disorder of the tilted octahedra is manifested as partial occupancy (25%) of the nonmetal site. A scheme to synthesize the anhydrous fluoride is presented.« less

Cation binding to a Bacillus (1,3-1,4)-beta-glucanase. Geometry, affinity and effect on protein stability.

PubMed

Keitel, T; Meldgaard, M; Heinemann, U

1994-05-15

The hybrid Bacillus (1,3-1,4)-beta-glucanase H(A16-M), consisting of 16 N-terminal amino acids derived from the mature form of the B. amyloliquefaciens enzyme and of 198 C-proximal amino acids from the B. macerans enzyme, binds a calcium ion at a site at its molecular surface remote from the active center [T. Keitel, O. Simon, R. Borriss & U. Heinemann (1993) Proc. Natl Acad. Sci. USA 90, 5287-5291]. X-ray diffraction analysis at 0.22-nm resolution of crystals grown in the absence of calcium and in the presence of EDTA shows this site to be occupied by a sodium ion. Whereas the calcium ion has six oxygen atoms in its coordination sphere, two of which are from water molecules, sodium is fivefold coordinated with a fifth ligand belonging to a symmetry-related protein molecule in the crystal lattice. The affinity of H(A16-M) for calcium over sodium has been determined calorimetrically. Calcium binding stabilizes the native three-dimensional structure of the protein as shown by guanidinium chloride unfolding and thermal inactivation experiments. The enhanced enzymic activity of Bacillus beta-glucanases at elevated temperatures in the presence of calcium ions is attributed to a general stabilizing effect by the cation.

Role of second-sphere coordination in anion binding: Synthesis, characterization and X-ray structure of hexaamminecobalt(III) chloride hydrogen phthalate trihydrate and sodium hexaamminecobalt(III) benzoate monohydrate

NASA Astrophysics Data System (ADS)

Sharma, Raj Pal; Bala, Ritu; Sharma, Rajni; Kariuki, B. M.; Rychlewska, Urszula; Warżajtis, Beata

2005-06-01

In an effort to utilize [Co(NH 3) 6] 3+cation as a new host for carboxylate ions, orange coloured crystalline solids of composition [Co(NH 3) 6]Cl(C 8H 5O 4) 2·3H 2O ( 1) and Na[Co(NH 3) 6](C 7H 5O 2) 4·H 2O ( 2) were obtained by reacting hot aqueous solutions of hexaamminecobalt(III) chloride with potassium hydrogen phthalate and sodium benzoate in 1:3 molar ratio, respectively. The title complex salts were characterized by elemental analyses and spectroscopic studies (IR, UV/Visible and NMR). Single crystal X-ray structure determinations revealed the formation of second-sphere coordination complexes based on hydrogen bond interactions. In complex salt 1 only two out of three ionisable chloride ions present in [Co(NH 3) 6]Cl 3 were replaced by two CHO4- ions whereas in complex salt 2 all the three ionisable chloride ions present in [Co(NH 3) 6]Cl 3 were replaced and the final product was an adduct with another mole of sodium benzoate in solid state. The crystal lattice is stabilized by electrostatic forces of attraction and predominantly N-H⋯O interactions.

Aluminum manganese oxides with mixed crystal structure: high-energy-density cathodes for rechargeable sodium batteries.

PubMed

Han, Dong-Wook; Ku, Jun-Hwan; Kim, Ryoung-Hee; Yun, Dong-Jin; Lee, Seok-Soo; Doo, Seok-Gwang

2014-07-01

We report a new discovery for enhancing the energy density of manganese oxide (Nax MnO2 ) cathode materials for sodium rechargeable batteries by incorporation of aluminum. The Al incorporation results in NaAl(0.1) Mn(0.9) O2 with a mixture of tunnel and layered crystal structures. NaAl(0.1) Mn(0.9) O2 shows a much higher initial discharge capacity and superior cycling performance compared to pristine Na(0.65) MnO2 . We ascribe this enhancement in performance to the formation of a new orthorhombic layered NaMnO2 phase merged with a small amount of tunnel Na(0.44) MnO2 phase in NaAl(0.1) Mn(0.9) O2 , and to improvements in the surface stability of the NaAl(0.1) Mn(0.9) O2 particles caused by the formation of Al-O bonds on their surfaces. Our findings regarding the phase transformation and structure stabilization induced by incorporation of aluminum, closely related to the structural analogy between orthorhombic Na(0.44) MnO2 and NaAl(0.1) Mn(0.9) O2 , suggest a strategy for achieving sodium rechargeable batteries with high energy density and stability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Beyond the detergent effect: a binding site for sodium dodecyl sulfate (SDS) in mammalian apoferritin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Renyu, E-mail: renyu.liu@uphs.upenn.edu; Bu, Weiming; Xi, Jin

2012-05-01

Using X-ray crystallography and isothermal titration calorimetry, we show that sodium dodecyl sulfate (SDS) binds specifically to a pre-formed internal cavity in horse-spleen apoferritin. Although sodium dodecyl sulfate (SDS) is widely used as an anionic detergent, it can also exert specific pharmacological effects that are independent of the surfactant properties of the molecule. However, structural details of how proteins recognize SDS are scarce. Here, it is demonstrated that SDS binds specifically to a naturally occurring four-helix bundle protein: horse apoferritin. The X-ray crystal structure of the apoferritin–SDS complex was determined at a resolution of 1.9 Å and revealed that themore » SDS binds in an internal cavity that has previously been shown to recognize various general anesthetics. A dissociation constant of 24 ± 9 µM at 293 K was determined by isothermal titration calorimetry. SDS binds in this cavity by bending its alkyl tail into a horseshoe shape; the charged SDS head group lies in the opening of the cavity at the protein surface. This crystal structure provides insights into the protein–SDS interactions that give rise to binding and may prove useful in the design of novel SDS-like ligands for some proteins.« less

Enhancing Entropy and Enthalpy Fluctuations to Drive Crystallization in Atomistic Simulations.

PubMed

Piaggi, Pablo M; Valsson, Omar; Parrinello, Michele

2017-07-07

Crystallization is a process of great practical relevance in which rare but crucial fluctuations lead to the formation of a solid phase starting from the liquid. As in all first order first transitions, there is an interplay between enthalpy and entropy. Based on this idea, in order to drive crystallization in molecular simulations, we introduce two collective variables, one enthalpic and the other entropic. Defined in this way, these collective variables do not prejudge the structure into which the system is going to crystallize. We show the usefulness of this approach by studying the cases of sodium and aluminum that crystallize in the bcc and fcc crystalline structures, respectively. Using these two generic collective variables, we perform variationally enhanced sampling and well tempered metadynamics simulations and find that the systems transform spontaneously and reversibly between the liquid and the solid phases.

Improvement of seawater salt quality by hydro-extraction and re-crystallization methods

NASA Astrophysics Data System (ADS)

Sumada, K.; Dewati, R.; Suprihatin

2018-01-01

Indonesia is one of the salt producing countries that use sea water as a source of raw materials, the quality of salt produced is influenced by the quality of sea water. The resulting average salt quality contains 85-90% NaCl. The Indonesian National Standard (SNI) for human salt’s consumption sodium chloride content is 94.7 % (dry base) and for industrial salt 98,5 %. In this study developed the re-crystallization without chemical and hydro-extraction method. The objective of this research to choose the best methods based on efficiency. The results showed that re-crystallization method can produce salt with NaCl content 99,21%, while hydro-extraction method content 99,34 % NaCl. The salt produced through both methods can be used as a consumption and industrial salt, Hydro-extraction method is more efficient than re-crystallization method because re-crystallization method requires heat energy.

New tooth enamel from brushite crystals

NASA Technical Reports Server (NTRS)

Rubin, B.; Childress, J. D.

1974-01-01

Appropriate nutrient gel solution could be used to precipitate brushite, which becomes hydroxyapatite, mineral found in bones and teeth. Gel can be made from sodium metasilicate and phosphoric acid, or gelatin, or other organic materials that polymerize in presence of acid to get gelantinous medium.

A Simple Tubular Reactor Experiment.

ERIC Educational Resources Information Center

Hudgins, Robert R.; Cayrol, Bertrand

1981-01-01

Using the hydrolysis of crystal violet dye by sodium hydroxide as an example, the theory, apparatus, and procedure for a laboratory demonstration of tubular reactor behavior are described. The reaction presented can occur at room temperature and features a color change to reinforce measured results. (WB)

Thermal expansion of the nuclear fuel-sodium reaction product Na3(U0.84(2),Na0.16(2))O4 - Structural mechanism and comparison with related sodium-metal ternary oxides

NASA Astrophysics Data System (ADS)

Illy, Marie-Claire; Smith, Anna L.; Wallez, Gilles; Raison, Philippe E.; Caciuffo, Roberto; Konings, Rudy J. M.

2017-07-01

Na3.16(2)UV,VI0.84(2)O4 is obtained from the reaction of sodium with uranium dioxide under oxygen potential conditions typical of a sodium-cooled fast nuclear reactor. In the event of a breach of the steel cladding, it would be the dominant reaction product forming at the rim of the mixed (U,Pu)O2 fuel pellets. High-temperature X-ray diffraction measurements show that a distortion of the uranium environment in Na3.16(2)UV,VI0.84(2)O4 results in a strongly anisotropic thermal expansion. A comparison with several related sodium metallates Nan-2Mn+On-1 - including Na3SbO4 and Na3TaO4, whose crystal structures are reported for the first time - has allowed us to assess the role played in the lattice expansion by the Mn+ cation radius and the Na/M ratio. On this basis, the thermomechanical behavior of the title compound is discussed, along with those of several related double oxides of sodium and actinide elements, surrogate elements, or fission products.

Rheological behavior and stability of ciprofloxacin suspension: Impact of structural vehicles and flocculating agent.

PubMed

Moghimipour, Eskandar; Rezaee, Saeed; Salimi, Anayatollah; Asadi, Elham; Handali, Somayeh

2013-07-01

Ciprofloxacin is a fluoroquinolone and is used against a broad spectrum of gram-negative and gram-positive bacteria. The aim of the study is to investigate the effect of structural vehicles and other formulating factors on physical stability and rheological behavior of ciprofloxacin suspension. To formulate the suspensions, the effect of glycerin and polysorbate 80 as wetting agents was evaluated. Then to achieve controlled flocculation, different concentrations of sodium chloride and calcium chloride were added. After choosing suitable wetting and flocculating agents, structural vehicles such as sodium carboxyl methyl cellulose (NaCMC), hydroxypropylmethylcellulose (HPMC) and Veegum were evaluated. Physical stability parameters such as sedimentation volume, the degree of flocculation and the ease of redispersion of the suspensions and growth of crystals were evaluated. After incorporation of structural vehicles, the rheological properties of formulations containing were also studied to find out their rheological behavior. According to the results, suspension containing glycerin (0.2% w/v) and sodium chloride (0.05% w/v) as wetting agent and flocculating agent, respectively, were the most stable formulations regarding their F and N. Microscopic observations showed the growth of crystals in ciprofloxacin suspension in formulation without excipients and the minimum amount of crystal growth was seen in suspension containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v). Rheological studies showed that almost all of the formulations had psuedoplastic behavior with different degree of thixotropy. The formulation containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v) was the most stable formulation. It may be concluded that by altering the amount ratios of formulation factors, the best rheological behavior and the most proper thixotropy may be achieved.

Rheological behavior and stability of ciprofloxacin suspension: Impact of structural vehicles and flocculating agent

PubMed Central

Moghimipour, Eskandar; Rezaee, Saeed; Salimi, Anayatollah; Asadi, Elham; Handali, Somayeh

2013-01-01

Ciprofloxacin is a fluoroquinolone and is used against a broad spectrum of gram-negative and gram-positive bacteria. The aim of the study is to investigate the effect of structural vehicles and other formulating factors on physical stability and rheological behavior of ciprofloxacin suspension. To formulate the suspensions, the effect of glycerin and polysorbate 80 as wetting agents was evaluated. Then to achieve controlled flocculation, different concentrations of sodium chloride and calcium chloride were added. After choosing suitable wetting and flocculating agents, structural vehicles such as sodium carboxyl methyl cellulose (NaCMC), hydroxypropylmethylcellulose (HPMC) and Veegum were evaluated. Physical stability parameters such as sedimentation volume, the degree of flocculation and the ease of redispersion of the suspensions and growth of crystals were evaluated. After incorporation of structural vehicles, the rheological properties of formulations containing were also studied to find out their rheological behavior. According to the results, suspension containing glycerin (0.2% w/v) and sodium chloride (0.05% w/v) as wetting agent and flocculating agent, respectively, were the most stable formulations regarding their F and N. Microscopic observations showed the growth of crystals in ciprofloxacin suspension in formulation without excipients and the minimum amount of crystal growth was seen in suspension containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v). Rheological studies showed that almost all of the formulations had psuedoplastic behavior with different degree of thixotropy. The formulation containing NaCMC (0.25% w/v), Veegum (0.1% w/v) and NaCl (0.05% w/v) was the most stable formulation. It may be concluded that by altering the amount ratios of formulation factors, the best rheological behavior and the most proper thixotropy may be achieved. PMID:24083201

Synthesis, structure and properties of bimetallic sodium rare-earth (RE) borohydrides, NaRE(BH4)4, RE = Ce, Pr, Er or Gd.

PubMed

Payandeh GharibDoust, SeyedHosein; Ravnsbæk, Dorthe B; Černý, Radovan; Jensen, Torben R

2017-10-10

Formation, stability and properties of new metal borohydrides within RE(BH 4 ) 3 -NaBH 4 , RE = Ce, Pr, Er or Gd is investigated. Three new bimetallic sodium rare-earth borohydrides, NaCe(BH 4 ) 4 , NaPr(BH 4 ) 4 and NaEr(BH 4 ) 4 are formed based on an addition reaction between NaBH 4 and halide free rare-earth metal borohydrides RE(BH 4 ) 3 , RE = Ce, Pr, Er. All the new compounds crystallize in the orthorhombic crystal system. NaCe(BH 4 ) 4 has unit cell parameters of a = 6.8028(5), b = 17.5181(13), c = 7.2841(5) Å and space group Pbcn. NaPr(BH 4 ) 4 is isostructural to NaCe(BH 4 ) 4 with unit cell parameters of a = 6.7617(2), b = 17.4678(7), c = 7.2522(3) Å. NaEr(BH 4 ) 4 crystallizes in space group Cmcm with unit cell parameters of a = 8.5379(2), b = 12.1570(4), c = 9.1652(3) Å. The structural relationships, also to the known RE(BH 4 ) 3 , are discussed in detail and related to the stability and synthesis conditions. Heat treatment of NaBH 4 -Gd(BH 4 ) 3 mixture forms an unstable amorphous phase, which decomposes after one day at RT. NaCe(BH 4 ) 4 and NaPr(BH 4 ) 4 show reversible hydrogen storage capacity of 1.65 and 1.04 wt% in the fourth H 2 release, whereas that of NaEr(BH 4 ) 4 continuously decreases. This is mainly assigned to formation of metal hydrides and possibly slower formation of sodium borohydride. The dehydrogenated state clearly contains rare-earth metal borides, which stabilize boron in the dehydrogenated state.

Reaction of sodium calcium borate glasses to form hydroxyapatite.

PubMed

Han, Xue; Day, Delbert E

2007-09-01

This study investigated the transformation of two sodium calcium borate glasses to hydroxyapatite (HA). The chemical reaction was between either 1CaO . 2Na(2)O . 6B(2)O(3) or 2CaO . 2Na(2)O . 6B(2)O(3) glass and a 0.25 M phosphate (K(2)HPO(4)) solution at 37, 75 and 200 degrees C. Glass samples in the form of irregular particles (125-180 microm) and microspheres (45-90 and 125-180 microm) were used in order to understand the reaction mechanism. The effect of glass composition (calcium content) on the weight loss rate and reaction temperature on crystal size, crystallinity and grain shape of the reaction products were studied. Carbonated HA was made by dissolving an appropriate amount of carbonate (K(2)CO(3)) in the 0.25 M phosphate solution. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used to characterize the reaction products. The results show that sodium calcium borate glasses can be transformed to HA by reacting with a phosphate solution. It is essentially a process of dissolution of glass and precipitation of HA. The transformation begins from an amorphous state to calcium-deficient HA without changing the size and shape of the original glass sample. Glass with a lower calcium content (1CaO . 2Na(2)O . 6B(2)O(3)), or reacted at an elevated temperature (75 degrees C), has a higher reaction rate. The HA crystal size increases and grain shape changes from spheroidal to cylindrical as temperature increases from 37 to 200 degrees C. Increase in carbonate concentration can also decrease the crystal size and yield a more needle-like grain shape.

Crystallization from microemulsions ? a novel method for the preparation of new crystal forms of aspartame

NASA Astrophysics Data System (ADS)

Füredi-Milhofer, Helga; Garti, N.; Kamyshny, A.

1999-03-01

Solubilization and crystallization of the artificial sweetener aspartame (APM), in water/isooctane microemulsions stabilized with sodium diisooctyl sulfosuccinate (AOT) has been investigated. The amount of aspartame that could be solubilized depended primarily on the amount of surfactant and on the temperature. The maximum AOT/aspartame molar ratio at the w/o interface is shown to be 6.2 at 25°C. It was concluded that the dipeptide is located at the w/o interface interspersed between surfactant molecules and that it acts as a cosurfactant. A new crystal form, APM III, was obtained by cooling of hot w/isooctane/AOT microemulsions containing solubilized aspartame. The new crystal form exhibits a distinct X-ray diffraction powder pattern, as well as changes in the FTIR spectra, thermogravimetric and DSC patterns. H-NMR spectra of APM III dissolved in D 2O were identical to the spectrum of commercial aspartame recorded under the same conditions. The new crystal form has greatly improved dissolution kinetics.

Growth of micro-crystals in solution by in-situ heating via continuous wave infrared laser light and an absorber

NASA Astrophysics Data System (ADS)

Pathak, Shashank; Dharmadhikari, Jayashree A.; Thamizhavel, A.; Mathur, Deepak; Dharmadhikari, Aditya K.

2016-01-01

We report on growth of micro-crystals such as sodium chloride (NaCl), copper sulphate (CuSO4), potassium di-hydrogen phosphate (KDP) and glycine (NH2CH2COOH) in solution by in-situ heating using continuous wave Nd:YVO4 laser light. Crystals are grown by adding single walled carbon nanotubes (SWNT). The SWNTs absorb 1064 nm light and act as an in-situ heat source that vaporizes the solvent producing microcrystals. The temporal dynamics of micro-crystal growth is investigated by varying experimental parameters such as SWNT bundle size and incident laser power. We also report crystal growth without SWNT in an absorbing medium: copper sulphate in water. Even though the growth dynamics with SWNT and copper sulphate are significantly different, our results indicate that bubble formation is necessary for nucleation. Our simple method may open up new vistas for rapid growth of seed crystals especially for examining the crystallizability of inorganic and organic materials.

16 CFR § 1507.2 - Prohibited chemicals.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Prohibited chemicals. § 1507.2 Section Â... REGULATIONS FIREWORKS DEVICES § 1507.2 Prohibited chemicals. Fireworks devices shall not contain any of the following chemicals: (a) Arsenic sulfide, arsenates, or arsenites. (b) Boron. (c) Chlorates, except: (1) In...

ENVIRONMENTAL AND POTASSIUM CHLORATE EFFECTS ON THE GROWTH OF CHAETOMIUM GLOBOSUM

EPA Science Inventory

Mold has been blamed for causing human health problems at work and at home. One fungus often found in indoor environments is Chaetomium globosum. This fungus produces sexual reproductive structures called perithecia (Fig. 2) that can be easily visualized on a media plate. Malt ex...

Factors Affecting the Plasticity of Sodium Chloride, Lithium Fluoride, and Magnesium Oxide Single Crystals. 1

NASA Technical Reports Server (NTRS)

Stearns, Carl A.; Pack, Ann E.; Lad, Robert A.

1959-01-01

A study was made of the relative magnitude of the effects of various factors on the ductility of single crystals of sodium chloride (NaCl), lithium fluoride (LiF), and magnesium oxide (MgO). Specimen treatments included water-polishing, varying cleavage rate, annealing, quenching, X-irradiation, surface coating, aging, and combinations of some of these treatments. The mechanical behavior of the crystals was studied in flexure and in compression, the latter study being performed at both constant strain rate and constant load. Etch-pit studies were carried out to provide some pertinent information on the results of pretreatment on the dislocation concentration and distribution in the vicinity of the surface. The load deformation curves for these ionic single crystals show an initial region of very low slope which proved to be due to anelastic deformation. The extent of initial anelastic deformation is modified by specimen pretreatment in a way that suggests that this deformation is the result of expansion of cleaved-in dislocation loops, which can contract on the removal of the stress. The effects of the various pretreatments on the load and deflection at fracture are in accord with the prediction one might make with regard to their effect on the nucleation of fatal surface cracks. For NaCl, increases in ductility are always accompanied by increases in strength. The creep constants for NaCl are a function of treatments which affect the bulk structure but are not a function of treatments which only affect the surface.

Bottom-up and Top-down Approaches to Explore Sodium Dodecyl Sulfate and Soluplus on the Crystallization Inhibition and Dissolution of Felodipine Extrudates.

PubMed

Chen, Jiali; Chen, Yuqi; Huang, Wencong; Wang, Hanning; Du, Yang; Xiong, Subin

2018-05-05

The objectives of this study were to explore sodium dodecyl sulfate (SDS) and Soluplus on the crystallization inhibition and dissolution of felodipine (FLDP) extrudates by bottom-up and top-down approaches. FLDP extrudates with Soluplus and/or SDS were prepared by hot melt extrusion (HME), and characterized by PLM, DSC and FT-IR. Results indicated that Soluplus inhibited FLDP crystallization and the whole amorphous solid dispersions (ASDs) were binary FLDP-Soluplus (1:3) and ternary FLDP-Soluplus-SDS(1:2:0.15∼0.3 and 1:3:0.2∼0.4) extrudates. Internal SDS (5%-10%) decreased Tgs of FLDP-Soluplus-SDS ternary ASDs without presenting molecular interactions with FLDP or Soluplus. The enhanced dissolution rate of binary or ternary Soluplus-rich ASDs in the non-sink condition of 0.05%SDS was achieved. Bottom-up approach indicated that Soluplus was a much stronger crystal inhibitor to the supersaturated FLDP in solutions than SDS. Top-down approach demonstrated that SDS enhanced the dissolution of Soluplus-rich ASDs via wettability and complexation with Soluplus to accelerate the medium uptake and erosion kinetics of extrudates, but induced FLDP recrystallization and resulted in incomplete dissolution of FLDP-rich extrudates. In conclusion, top-down approach is a promising strategy to explore the mechanisms of ASDs' dissolution, and small amount of SDS enhances the dissolution rate of polymer-rich ASDs in the non-sink condition. Copyright © 2018. Published by Elsevier Inc.

Physicochemical characterization of tacrolimus-loaded solid dispersion with sodium carboxylmethyl cellulose and sodium lauryl sulfate.

PubMed

Park, Young-Joon; Ryu, Dong-Sung; Li, Dong Xun; Quan, Qi Zhe; Oh, Dong Hoon; Kim, Jong Oh; Seo, Youn Gee; Lee, Young-Im; Yong, Chul Soon; Woo, Jong Soo; Choi, Han-Gon

2009-06-01

To develop a novel tacrolimus-loaded solid dispersion with improved solubility, various solid dispersions were prepared with various ratios of water, sodium lauryl sulfate, citric acid and carboxylmethylcellulose-Na using spray drying technique. The physicochemical properties of solid dispersions were investigated using scanning electron microscopy, differential scanning calorimetery and powder X-ray diffraction. Furthermore, their solubility and dissolution were evaluated compared to drug powder. The solid dispersion at the tacrolimus/CMC-Na/sodium lauryl sulfate/citric acid ratio of 3/24/3/0.2 significantly improved the drug solubility and dissolution compared to powder. The scanning electron microscopy result suggested that carriers might be attached to the surface of drug in this solid dispersion. Unlike traditional solid dispersion systems, the crystal form of drug in this solid dispersion could not be converted to amorphous form, which was confirmed by the analysis of DSC and powder X-ray diffraction. Thus, the solid dispersion system with water, sodium lauryl sulfate, citric acid and CMC-Na should be a potential candidate for delivering a poorly water-soluble tacrolimus with enhanced solubility and no convertible crystalline.

Salt microspheres and potassium chloride usage for sodium reduction: Case study with sushi.

PubMed

Đorđević, Đani; Buchtová, Hana; Macharáčková, Blanka

2018-01-01

The aim of the study was to estimate possibilities of salt substitutes usage in the preparation of two sushi types (nigiri and maki) prepared with different seafood (salmon: Salmo salar, tuna: Thunnus albacares, and shrimp: Pleoticus muelleri). Potassium chloride (Mary samples), Soda-Lo (hollowed microsphere of regular salt crystals), and regular salt (sodium chloride) were used in the experiment. Sushi samples (n = 1960) were evaluated by 40 trained panelists who noticed that maki shrimp samples prepared with Mary salt had higher bitterness (21.48 ± 28.01) in comparison with 2% sodium chloride (7.91 ± 8.80). The saltiness was lower in nigiri tuna prepared with Mary (49.59 ± 17.47) than 2% sodium chloride (61.11 ± 15.75). The study clearly showed the possibility of lowering sodium content in sushi meal with the usage of salt substitutes, with emphasis that Soda-Lo should be considered as a better option due to the retention of sensory properties in sushi samples prepared with this salt substitute.

Melt-state rheology, solid-state mechanical properties and microstructure of polymer-clay nanocomposites

NASA Astrophysics Data System (ADS)

Somwangthanaroj, Anongnat

Polymer/clay nanocomposites have the potential usefulness in industrial applications such as automotive and packaging due to their strong, light-weight and inexpensive properties. However, to respond to needs of various applications it is crucial to understand the crystallization and rheological properties of these materials. Our initial hypothesis was that the processing conditions such as shear rate, shear strain and temperature affect the crystallization kinetics of intercalated polypropylene nanocomposites. Another hypothesis was that the compatibilizer, PP-MA, affects the role of the nucleating agent, sodium benzoate. The final hypothesis was that the rheological properties of nanocomposites depend on the degree of clay dispersion. By means of time-resolved small-angle light scattering, we were able to demonstrate that clay enhances the crystallization kinetics in nanocomposites and its result differs significantly from that of pure polypropylene. Characteristic crystallization times are extracted from the time evolution of integral measures of the angularly dependent parallel polarized and cross polarized light scattering intensity. Flow acceleration of crystallization kinetics has been observed for the polymer nanocomposites at applied strain rates for which flow has only modest effect on polypropylene crystallization. Furthermore, we were able to conclude that the addition of the nucleating agent sodium benzoate in the presence of polypropylene grafted maleic anhydride is not effective in accelerating crystallization. The rheological properties of two types of polypropylene/clay nanocomposites, with different degrees of clay dispersion have been measured in both linear and non-linear viscoelastic regime. In the linear viscoelastic regime, the storage and loss modulus of nanocomposites increases when clay loading increases. The storage and loss modulus of unsonicated nanocomposites are higher than the sonicated ones because the ultrasonic processing alters the structure of clay and polymer blend in sonicated nanocomposite. Non-linear rheology addresses the possible structure of particulate domains of clays in polymers. From this research, we demonstrated the possible effect of clay and compatibilizer on the crystallization kinetics and the effect of structure of clay and polymer matrix on rheological properties. To understand how clay enhances the mechanical properties, we still need to investigate where the clay actually resides and how the polymer crystallite forms.

Heterologous expression, purification, crystallization and preliminary X-ray analysis of raucaffricine glucosidase, a plant enzyme specifically involved in Rauvolfia alkaloid biosynthesis

PubMed Central

Ruppert, Martin; Panjikar, Santosh; Barleben, Leif; Stöckigt, Joachim

2006-01-01

Raucaffricine glucosidase (RG) is an enzyme that is specifically involved in the biosynthesis of indole alkaloids from the plant Rauvolfia serpentina. After heterologous expression in Escherichia coli cells, crystals of RG were obtained by the hanging-drop vapour-diffusion technique at 293 K with 0.3 M ammonium sulfate, 0.1 M sodium acetate pH 4.6 buffer and 11% PEG 4000 as precipitant. Crystals belong to space group I222 and diffract to 2.30 Å, with unit-cell parameters a = 102.8, b = 127.3, c = 215.8 Å. PMID:16511316

A facile approach towards synthesis, characterization, single crystal structure, and DFT study of 5-bromosalicylalcohol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rastogi, Rupali, E-mail: rastogirupali@ymail.com; Tarannum, Nazia; Butcher, R. J.

2016-03-15

5-Bromosalicylalcohol was prepared by the interaction of NaBH{sub 4} and 5-bromosalicylaldehyde. The use of sodium borohydride makes the reaction easy, facile, economic and does not require any toxic catalyst. The compound is characterized by FTIR, {sup 1}H NMR, {sup 13}C NMR, TEM and ESI-mass spectra. Crystal structure is determined by single crystal X-ray analysis. Quantum mechanical calculations of geometries, energies and thermodynamic parameters are carried out using density functional theory (DFT/B3LYP) method with 6-311G(d,p) basis set. The optimized geometrical parameters obtained by B3LYP method show good agreement with experimental data.

Effect of counterion binding efficiency on structure and dynamics of wormlike micelles.

PubMed

Oelschlaeger, C; Suwita, P; Willenbacher, N

2010-05-18

We have studied the effect of counterion binding efficiency on the linear viscoelastic properties of wormlike micelles formed from hexadecyltrimethylammonium bromide (CTAB) in the presence of different nonpenetrating inorganic salts: potassium bromide (KBr), sodium nitrate (NaNO(3)), and sodium chlorate (NaClO(3)). We have varied the salt/surfactant ratio R at fixed surfactant concentration of 350 mM. Results are compared to data for the system cetylpyridinium chloride (CPyCl) and the penetrating counterion sodium salicylate (NaSal) (Oelschlaeger, C.; Schopferer, M.; Scheffold, F.; Willenbacher, N. Langmuir 2009, 25, 716-723). Mechanical high-frequency rheology and diffusing wave spectroscopy (DWS) based tracer microrheology are used to determine the shear moduli G' and G'' in the frequency range from 0.1 Hz up to 1 MHz (Willenbacher, N.; Oelschlaeger, C.; Schopferer, M.; Fischer, P.; Cardinaux, F.; Scheffold, F. Phys. Rev. Lett. 2007, 99, 068302, 1-4). This enables us to determine the plateau modulus G(0), which is related to the cross-link density or mesh size of the entanglement network, the bending stiffness kappa (also expressed as persistence length l(p) = kappa/k(B)T) corresponding to the semiflexible nature of the micelles, and the scission energy E(sciss), which is related to their contour length. The viscosity maximum shifts to higher R values, and the variation of viscosity with R is less pronounced as the binding strength decreases. The plateau modulus increases with R at low ionic strength and is constant around the viscosity maximum; the increase in G(0) at high R, which is presumably due to branching, is weak compared to the system with penetrating counterion. The scission energy E(sciss) approximately = 20 k(B)T is independent of counterion binding efficiency irrespective of R and is slightly higher compared to the system CPyCl/NaSal, indicating that branching may be significant already at the viscosity maximum in this latter case. The micellar flexibility increases with increasing binding efficiency of counterions according to the Hofmeister series. The persistence length values for systems CTAB/KBr, CTAB/NaNO(3), and CTAB/NaClO(3) are 40, 34, and 29 nm, respectively, independent of R, and are significantly higher than in the case of CPyCl/NaSal.

Crystallization of dienelactone hydrolase in two space groups: structural changes caused by crystal packing

PubMed Central

Porter, Joanne L.; Carr, Paul D.; Collyer, Charles A.; Ollis, David L.

2014-01-01

Dienelactone hydrolase (DLH) is a monomeric protein with a simple α/β-hydrolase fold structure. It readily crystallizes in space group P212121 from either a phosphate or ammonium sulfate precipitation buffer. Here, the structure of DLH at 1.85 Å resolution crystallized in space group C2 with two molecules in the asymmetric unit is reported. When crystallized in space group P212121 DLH has either phosphates or sulfates bound to the protein in crucial locations, one of which is located in the active site, preventing substrate/inhibitor binding. Another is located on the surface of the enzyme coordinated by side chains from two different molecules. Crystallization in space group C2 from a sodium citrate buffer results in new crystallographic protein–protein interfaces. The protein backbone is highly similar, but new crystal contacts cause changes in side-chain orientations and in loop positioning. In regions not involved in crystal contacts, there is little change in backbone or side-chain configuration. The flexibility of surface loops and the adaptability of side chains are important factors enabling DLH to adapt and form different crystal lattices. PMID:25005082

Crystallization and preliminary X-ray crystallographic analysis of an ice-binding protein (FfIBP) from Flavobacterium frigoris PS1.

PubMed

Do, Hackwon; Lee, Jun Hyuck; Lee, Sung Gu; Kim, Hak Jun

2012-07-01

Ice growth in a cold environment is fatal for polar organisms, not only because of the physical destruction of inner cell organelles but also because of the resulting chemical damage owing to processes such as osmotic shock. The properties of ice-binding proteins (IBPs), which include antifreeze proteins (AFPs), have been characterized and IBPs exhibit the ability to inhibit ice growth by binding to specific ice planes and lowering the freezing point. An ice-binding protein (FfIBP) from the Gram-negative bacterium Flavobacterium frigoris PS1, which was isolated from the Antarctic, has recently been overexpressed. Interestingly, the thermal hysteresis activity of FfIBP was approximately 2.5 K at 50 µM, which is ten times higher than that of the moderately active IBP from Arctic yeast (LeIBP). Although FfIBP closely resembles LeIBP in its amino-acid sequence, the antifreeze activity of FfIBP appears to be much greater than that of LeIBP. In an effort to understand the reason for this difference, an attempt was made to solve the crystal structure of FfIBP. Here, the crystallization and X-ray diffraction data of FfIBP are reported. FfIBP was crystallized using the hanging-drop vapour-diffusion method with 0.1 M sodium acetate pH 4.4 and 3 M sodium chloride as precipitant. A complete diffraction data set was collected to a resolution of 2.9 Å. The crystal belonged to space group P4(1)22, with unit-cell parameters a = b = 69.4, c = 178.2 Å. The asymmetric unit contained one monomer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Xuetian; An, Ke; Bai, Jianmin

Sodium ion batteries are being considered as an alternative to lithium ion batteries in large-scale energy storage applications owing to the low cost. In this paper, a novel titanate compound, NaAlTi 3O 8, was successfully synthesized and tested as a promising anode material for sodium ion batteries. Powder X-ray Diffraction (XRD) and refinement were used to analyze the crystal structure. Electrochemical cycling tests under a C/10 rate between 0.01 - 2.5 V showed that ~83 mAh/g capacity could be achieved in the second cycle, with ~75% of which retained after 100 cycles, which corresponds to 0.75 Na + insertion andmore » extraction. The influence of synthesis conditions on electrochemical performances was investigated and discussed. Finally, NaAlTi 3O 8 not only presents a new anode material with low average voltage of ~0.5 V, but also provides a new type of intercalation anode with a crystal structure that differentiates from the anodes that have been reported.« less

Mild hydrothermal crystal growth of new uranium(IV) fluorides, Na{sub 3.13}Mg{sub 1.43}U{sub 6}F{sub 30} and Na{sub 2.50}Mn{sub 1.75}U{sub 6}F{sub 30}: Structures, optical and magnetic properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeon, Jeongho; Smith, Mark D.; Tapp, Joshua

Two new uranium(IV) fluorides, Na{sub 3.13}Mg{sub 1.43}U{sub 6}F{sub 30} (1) and Na{sub 2.50}Mn{sub 1.75}U{sub 6}F{sub 30} (2), were synthesized through an in situ mild hydrothermal route, and were structurally characterized by single crystal X-ray diffraction. The compounds exhibit complex crystal structures composed of corner- or edge-shared UF{sub 9} and MF{sub 6} (M=Mg, Mn) polyhedra, forming hexagonal channels in the three-dimensional framework, in which ordered or disordered divalent metal and sodium atoms reside. The large hexagonal voids contain the nearly regular M(II)F{sub 6} octahedra and sodium ions, whereas the small hexagonal cavities include M(II) and sodium ions on a mixed-occupied site.more » Magnetic susceptibility measurements yielded effective magnetic moments of 8.36 and 11.6 µ{sub B} for 1 and 2, respectively, confirming the presence and oxidation states of U(IV) and Mn(II). The large negative Weiss constants indicate the spin gap between a triplet and a singlet state in the U(IV). Magnetization data as a function of applied fields revealed that 2 exhibits paramagnetic behavior due to the nonmagnetic singlet ground state of U(IV) at low temperature. UV–vis diffuse reflectance and X-ray photoelectron spectroscopy data were also analyzed. - Graphical abstract: Two new quaternary U(IV) fluorides, Na{sub 3.13}Mg{sub 1.43}U{sub 6}F{sub 30} and Na{sub 2.50}Mn{sub 1.75}U{sub 6}F{sub 30}, were crystallized via an in situ reduction step of U(VI) to U(IV) under mild hydrothermal conditions. The compounds show complex crystal structures based on the 3-D building block of U{sub 6}F{sub 30}. Magnetic property measurements revealed that the U(IV) exhibits a nonmagnetic singlet ground state at low temperature with a spin gap. - Highlights: • Na{sub 3.13}Mg{sub 1.43}U{sub 6}F{sub 30} and Na{sub 2.50}Mn{sub 1.75}U{sub 6}F{sub 30} have been synthesized and characterized. • The U(IV) fluorides exhibit complex three-dimensional crystal structures. • The optical properties were investigated. • Magnetic susceptibility data were collected.« less

Determination of induction period and crystal growth mechanism of dexamethasone sodium phosphate in methanol-acetone system

NASA Astrophysics Data System (ADS)

Hao, Hongxun; Wang, Jingkang; Wang, Yongli

2005-02-01

The induction period of dexamethasone sodium phosphate at different supersaturation was experimentally determined in a methanol-acetone system. The laser monitoring observation technique was used to determine the appearance of the first nucleus in solution. The effect of solution composition on induction period was discussed. Based on classical homogeneous nucleation theory, the solid-liquid interfacial tension and surface entropy factor were calculated from the induction period data. The experimentally determined values of interfacial tension are in agreement with the theoretical values predicted by the Mersmann equation. It was found that the nucleus of dexamethasone sodium phosphate grows continuously in pure methanol and turns from continuous growth to birth and spread growth with increasing acetone content in a methanol-acetone mixture.

Review on Material Synthesis and Characterization of Sodium (Na) Super-Ionic Conductor (NASICON)

NASA Astrophysics Data System (ADS)

Kimpa, M. I.; Mayzan, M. Z. H.; Yabagi, J. A.; Nmaya, M. M.; Isah, K. U.; Agam, M. A.

2018-04-01

Sodium (Na) Super Ionic Conductor (NASICON) has general formula Na1+ x Zr2P3- xSi x O12 (0 ≤x ≤ 3) derived from its parent compound, sodium zirconium phosphate NaZr2(PO4)3 (NZP) which belong to a rhombohedral crystal structure. This material consists of three-dimensional structure with interesting features such as low thermal expansion coefficient, thermal stability, gas sensor and nuclear waste immobilization that make it viable for industrial applications. Current study presents comprehensive studies on the synthesis and essential characteristics required to understand the theory behind the mechanism that justifies the study of NASICON structure and its application such as lithium ion rechargeable battery, gas sensor, and nuclear waste immobilization and so on.

Crystal structure, spectral, thermal and dielectric studies of a new zinc benzoate single crystal

NASA Astrophysics Data System (ADS)

Bijini, B. R.; Prasanna, S.; Deepa, M.; Nair, C. M. K.; Rajendra Babu, K.

2012-11-01

Single crystals of zinc benzoate with a novel structure were grown in gel media. Sodium metasilicate of gel density 1.04 g/cc at pH 6 was employed to yield transparent single crystals. The crystal structure of the compound was ascertained by single crystal X-ray diffractometry. It was noted that the crystal belongs to monoclinic system with space group P21/c with unit cell parameters a = 10.669(1) Å, b = 12.995(5) Å, c = 19.119(3) Å, and β = 94.926(3)°. The crystal was seen to possess a linear polymeric structure along b-axis; with no presence of coordinated or lattice water. CHN analysis established the stoichiometric composition of the crystal. The existence of functional groups present in the single crystal system was confirmed by FT-IR studies. The thermal characteristic of the sample was analysed by TGA-DTA techniques, and the sample was found to be thermally stable up to 280 °C. The kinetic and thermodynamic parameters were also determined. UV-Vis spectroscopy corroborated the transparency of the crystal and revealed the optical band gap to be 4 eV. Dielectric studies showed decrease in the dielectric constant of the sample with increase in frequency.

The Use of Backscattered Electron Imaging and Transmission Electron Microscopy to Assess Bone Architecture and Mineral Loci: Effect of Intermittent Slow-Release Sodium Fluoride Therapy

NASA Astrophysics Data System (ADS)

Zerwekh, Joseph E.; Bellotto, Dennis; Prostak, Kenneth S.; Hagler, Herbert K.; Pak, Charles Y. C.

1996-04-01

Backscattered electron imaging (BEI) and transmission electron microscopy (TEM) were used to examine the effects of treatment with intermittent slow-release sodium fluoride (SRNaF) and continuous calcium citrate on bone architecture and crystallinity. Examination was performed in nondecalcified biopsies obtained from patients following up to four years of therapy (placebo or SRNaF) and compared to pretreatment biopsies from each patient, as well as to bone from young, normal subjects. BEI images disclosed increased areas of recent bone formation following fluoride administration. There was no evidence of a mineralization defect in any biopsy and both cortical and trabecular architecture remained normal. TEM analysis demonstrated intrafibrillar platelike crystals and extrafibrillar needlelike crystals for both the pre- and post-treatment biopsies as well as for the bone from young normal subjects. There was no evidence of increased crystal size or of an increase in extrafibrillar mineral deposition. These observations suggest that intermittent SRNaF and continuous calcium therapy exerts an anabolic action on the skeleton not accompanied by a mineralization defect or an alteration of bone mineral deposition. The use of BEI and TEM holds promise for the study of the pathophysiology and treatment of metabolic bone diseases.

Electromechanical properties of engineered lead free potassium sodium niobate based materials =

NASA Astrophysics Data System (ADS)

Rafiq, Muhammad Asif

K0.5Na0.5NbO3 (KNN), is the most promising lead free material for substituting lead zirconate titanate (PZT) which is still the market leader used for sensors and actuators. To make KNN a real competitor, it is necessary to understand and to improve its properties. This goal is pursued in the present work via different approaches aiming to study KNN intrinsic properties and then to identify appropriate strategies like doping and texturing for designing better KNN materials for an intended application. Hence, polycrystalline KNN ceramics (undoped, non-stoichiometric; NST and doped), high-quality KNN single crystals and textured KNN based ceramics were successfully synthesized and characterized in this work. Polycrystalline undoped, non-stoichiometric (NST) and Mn doped KNN ceramics were prepared by conventional ceramic processing. Structure, microstructure and electrical properties were measured. It was observed that the window for mono-phasic compositions was very narrow for both NST ceramics and Mn doped ceramics. For NST ceramics the variation of A/B ratio influenced the polarization (P-E) hysteresis loop and better piezoelectric and dielectric responses could be found for small stoichiometry deviations (A/B = 0.97). Regarding Mn doping, as compared to undoped KNN which showed leaky polarization (P-E) hysteresis loops, B-site Mn doped ceramics showed a well saturated, less-leaky hysteresis loop and a significant properties improvement. Impedance spectroscopy was used to assess the role of Mn and a relation between charge transport - defects and ferroelectric response in K0.5Na0.5NbO3 (KNN) and Mn doped KNN ceramics could be established. At room temperature the conduction in KNN which is associated with holes transport is suppressed by Mn doping. Hence Mn addition increases the resistivity of the ceramic, which proved to be very helpful for improving the saturation of the P-E loop. At high temperatures the conduction is dominated by the motion of ionized oxygen vacancies whose concentration increases with Mn doping. Single crystals of potassium sodium niobate (KNN) were grown by a modified high temperature flux method. A boron-modified flux was used to obtain the crystals at a relatively low temperature. XRD, EDS and ICP analysis proved the chemical and crystallographic quality of the crystals. The grown KNN crystals exhibit higher dielectric permittivity (29,100) at the tetragonal-to-cubic phase transition temperature, higher remnant polarization (19.4 ?C/cm2) and piezoelectric coefficient (160 pC/N) when compared with the standard KNN ceramics. KNN single crystals domain structure was characterized for the first time by piezoforce response microscopy. It could be observed that - oriented potassium sodium niobate (KNN) single crystals reveal a long range ordered domain pattern of parallel 180° domains with zig-zag 90° domains. From the comparison of KNN Single crystals to ceramics, It is argued that the presence in KNN single crystal (and absence in KNN ceramics) of such a long range order specific domain pattern that is its fingerprint accounts for the improved properties of single crystals. These results have broad implications for the expanded use of KNN materials, by establishing a relation between the domain patterns and the dielectric and ferroelectric response of single crystals and ceramics and by indicating ways of achieving maximised properties in KNN materials. (Abstract shortened by ProQuest.).

Inhibiting surface crystallization of amorphous indomethacin by nanocoating.

PubMed

Wu, Tian; Sun, Ye; Li, Ning; de Villiers, Melgardt M; Yu, Lian

2007-04-24

An amorphous solid (glass) may crystallize faster at the surface than through the bulk, making surface crystallization a mechanism of failure for amorphous pharmaceuticals and other materials. An ultrathin coating of gold or polyelectrolytes inhibited the surface crystallization of amorphous indomethacin (IMC), an anti-inflammatory drug and model organic glass. The gold coating (10 nm) was deposited by sputtering, and the polyelectrolyte coating (3-20 nm) was deposited by an electrostatic layer-by-layer assembly of cationic poly(dimethyldiallyl ammonium chloride) (PDDA) and anionic sodium poly(styrenesulfonate) (PSS) in aqueous solution. The coating also inhibited the growth of existing crystals. The inhibition was strong even with one layer of PDDA. The polyelectrolyte coating still permitted fast dissolution of amorphous IMC and improved its wetting and flow. The finding supports the view that the surface crystallization of amorphous IMC is enabled by the mobility of a thin layer of surface molecules, and this mobility can be suppressed by a coating of only a few nanometers. This technique may be used to stabilize amorphous drugs prone to surface crystallization, with the aqueous coating process especially suitable for drugs of low aqueous solubility.

SABRE: A New NaI(T1) Dark Matter Direct Detection Experiment

NASA Astrophysics Data System (ADS)

Shields, Emily; Xu, Jingke; Calaprice, Frank

SABRE (Sodium-iodide with Active Background REjection) is a new NaI(Tl) experiment designed to test the DAMA/LIBRA claim for a positive WIMP-dark matter annual modulation signal. SABRE will consist of highly pure NaI(Tl) crystals in an active liquid scintillator veto that will be placed deep underground. The scintillator vessel will provide a veto against external backgrounds and those arising from detector components, especially the 3 keV signature from the decay of 40K in the crystal. Through the use of crystal purification techniques and the veto, we aim for a 40K background significantly lower than that of the DAMA/LIBRA experiment. We present our work developing low-background NaI(Tl) crystals using a highly pure NaI powder and the development of the veto.

Synthesis and characterization of a prominent NLO active MOF of lead with 1,5-naphthalenedisulfonic acid

NASA Astrophysics Data System (ADS)

Prasad, S. Shibu; Sudarsanakumar, M. R.; Dhanya, V. S.; Suma, S.; Kurup, M. R. Prathapachandra

2018-09-01

A new metal-organic framework of lead, [Pb(1,5-nds)(H2O)3]n (1,5-nds = 1,5-naphthalenedisulfonate) having prominent nonlinear optical property has been prepared by single gel diffusion technique at ambient condition using sodium metasilicate. The second harmonic generation efficiency was analyzed using Kurtz and Perry powder method and was found to be 30 times as large as potassium dihydrogen phosphate (KDP). Single crystal X-ray diffraction studies reveal the crystal structure. The grown crystals were further characterized by elemental analysis, powder XRD study, thermogravimetry, FT-IR and UV-visible spectral studies. The Pb2S2O4 rings in the crystal structure form a 1D channel. Hydrogen bonding and π-π interactions provide additional stability to the compound. Photoluminescence studies were also carried out.

Favorite Demonstrations: Exothermic Crystallization from a Supersaturated Solution.

ERIC Educational Resources Information Center

Kauffman, George B.; And Others

1986-01-01

The use of sodium acetate solution to show supersaturation is a favorite among lecture demonstrations. However, careful adjustment of the solute-to-water ratio must be made to attain the most spectacular effect--complete solidification of the solution. Procedures to accomplish this are provided and discussed. (JN)

Structural model of the open–closed–inactivated cycle of prokaryotic voltage-gated sodium channels

PubMed Central

Bagnéris, Claire; Naylor, Claire E.; McCusker, Emily C.

2015-01-01

In excitable cells, the initiation of the action potential results from the opening of voltage-gated sodium channels. These channels undergo a series of conformational changes between open, closed, and inactivated states. Many models have been proposed for the structural transitions that result in these different functional states. Here, we compare the crystal structures of prokaryotic sodium channels captured in the different conformational forms and use them as the basis for examining molecular models for the activation, slow inactivation, and recovery processes. We compare structural similarities and differences in the pore domains, specifically in the transmembrane helices, the constrictions within the pore cavity, the activation gate at the cytoplasmic end of the last transmembrane helix, the C-terminal domain, and the selectivity filter. We discuss the observed differences in the context of previous models for opening, closing, and inactivation, and present a new structure-based model for the functional transitions. Our proposed prokaryotic channel activation mechanism is then compared with the activation transition in eukaryotic sodium channels. PMID:25512599

Anaerobic Degradation of Benzene, Toluene, Ethylbenzene, and Xylene Compounds by Dechloromonas Strain RCB

PubMed Central

Chakraborty, Romy; O'Connor, Susan M.; Chan, Emily; Coates, John D.

2005-01-01

Dechloromonas strain RCB has been shown to be capable of anaerobic degradation of benzene coupled to nitrate reduction. As a continuation of these studies, the metabolic versatility and hydrocarbon biodegradative capability of this organism were investigated. The results of these revealed that in addition to nitrate, strain RCB could alternatively degrade benzene both aerobically and anaerobically with perchlorate or chlorate [(per)chlorate] as a suitable electron acceptor. Furthermore, with nitrate as the electron acceptor, strain RCB could also utilize toluene, ethylbenzene, and all three isomers of xylene (ortho-, meta-, and para-) as electron donors. While toluene and ethylbenzene were completely mineralized to CO2, strain RCB did not completely mineralize para-xylene but rather transformed it to some as-yet-unidentified metabolite. Interestingly, with nitrate as the electron acceptor, strain RCB degraded benzene and toluene concurrently when the hydrocarbons were added as a mixture and almost 92 μM total hydrocarbons were oxidized within 15 days. The results of these studies emphasize the unique metabolic versatility of this organism, highlighting its potential applicability to bioremediative technologies. PMID:16332859

Effects of magnetic fields on dissolution of arthritis causing crystals

NASA Astrophysics Data System (ADS)

Takeuchi, Y.; Iwasaka, M.

2015-05-01

The number of gout patients has rapidly increased because of excess alcohol and salt intake. The agent responsible for gout is the monosodium urate (MSU) crystal. MSU crystals are found in blood and consist of uric acid and sodium. As a substitute for drug dosing or excessive water intake, physical stimulation by magnetic fields represents a new medical treatment for gout. In this study, we investigated the effects of a magnetic field on the dissolution of a MSU crystal suspension. The white MSU crystal suspension was dissolved in an alkaline solution. We measured the light transmission of the MSU crystal suspension by a transmitted light measuring system. The magnetic field was generated by a horizontal electromagnet (maximum field strength was 500 mT). The MSU crystal suspension that dissolved during the application of a magnetic field of 500 mT clearly had a higher dissolution rate when compared with the control sample. We postulate that the alkali solution promoted penetration upon diamagnetic rotation and this magnetic field orienting is because of the pronounced diamagnetic susceptibility anisotropy of the MSU crystal. The results indicate that magnetic fields represent an effective gout treatment approach.

Odd-even chain packing, molecular and thermal models for some long chain sodium(I) n-alkanoates

NASA Astrophysics Data System (ADS)

Nelson, Peter N.; Ellis, Henry A.

2014-10-01

A homologous series of sodium(I) n-alkanoates, NaCnH2n-1O2, with chain lengths n = 8-18, inclusive, have been synthesized and their structural and thermal properties investigated via Fourier Transform Infrared and Solid State 13C NMR spectroscopies, X-ray powder diffraction, Thermogravimetry, Differential Scanning Calorimetry, Polarizing light microscopy and variable temperature Infrared spectroscopy. The measurements show that metal-carboxylate coordination is via asymmetric chelating bidentate bonding with extensive carboxyl group inter-molecular interactions in which four oxygen atoms are bonded tetrahedrally to a sodium atom. Furthermore, the compounds crystallize in a monoclinic crystal system with the hydrocarbon chains in the fully extended all-trans conformation, advancing along the c-axis. Moreover, the chains are packed as tilted (θ ∼ 63°), non-overlapping, tail-to-tail lamellar bilayers that are not in the same plane, within a lamellar. Though these compounds are nearly isostructural, there are subtle differences in the packing of the hydrocarbon chains in the crystal lattice, resulting in odd-even alternation in the terminal methyl group asymmetric stretching vibration and chemical shift. These differences arise from the relative vertical distances between hydrocarbon planes within the lamellar; such that, for odd-chain compounds, larger inter-planar distances result in less efficient packing in the crystal lattice and hence, lower inter-planar van der Waals interactions between hydrocarbon chains. Thermal traces, for all compounds, show several partially reversible solid-solid pre-melting transitions associated with different degrees of gauche conformers in the alkyl chains. The reversible gauche-trans isomerism, of the methylene groups, is kinetically controlled; hence, super-cooling of the melt and other transitions, are observed for all compounds. The kinetics of chain reversion follow the exponential law of nucleation, though complicated by competing processes. Thermogravimetric data show that all compounds decompose at temperatures in excess of 690 K; therefore, free radical thermal cracking of the hydrocarbon chains, in conjunction with decarboxylation is proposed for their non-oxidative degradation mechanism.

Inhibition mechanism of hydroxypropyl methylcellulose acetate succinate on drug crystallization in gastrointestinal fluid and drug permeability from a supersaturated solution.

PubMed

Ueda, Keisuke; Higashi, Kenjirou; Kataoka, Makoto; Yamashita, Shinji; Yamamoto, Keiji; Moribe, Kunikazu

2014-10-01

The effects of drug-crystallization inhibitor in bile acid/lipid micelles solution on drug permeation was evaluated during the drug crystallization process. Hydroxypropyl methylcellulose acetate succinate (HPMC-AS) was used as a drug-crystallization inhibitor, which efficiently suppressed dexamethasone (DEX) crystallization in a gastrointestinal fluid model containing sodium taurocholate (NaTC) and egg-phosphatidylcholine (egg-PC). Changes of molecular state of supersaturated DEX during the DEX crystallization process was monitored in real time using proton nuclear magnetic resonance (1H NMR). It revealed that DEX distribution to bulk water and micellar phases formed by NaTC and egg-PC was not changed during the DEX crystallization process even in the presence of HPMC-AS. DEX permeation during DEX crystallization was evaluated using dissolution/permeability system. The combination of crystallization inhibition by HPMC-AS and micellar encapsulation by NaTC and egg-PC led to considerably higher DEX concentrations and improvement of DEX permeation at the beginning of the DEX crystallization process. Crystallization inhibition by HPMC-AS can efficiently work even in the micellar solution, where NaTC/egg-PC micelles encapsulates some DEX. It was concluded that a crystallization inhibitor contributed to improvement of permeation of a poorly water-soluble drug in gastrointestinal fluid. Copyright © 2014 Elsevier B.V. All rights reserved.

Microwave Diffraction Techniques from Macroscopic Crystal Models

ERIC Educational Resources Information Center

Murray, William Henry

1974-01-01

Discusses the construction of a diffractometer table and four microwave models which are built of styrofoam balls with implanted metallic reflecting spheres and designed to simulate the structures of carbon (graphite structure), sodium chloride, tin oxide, and palladium oxide. Included are samples of Bragg patterns and computer-analysis results.…

Glucose-Neopentyl Glycol (GNG) Amphiphiles for Membrane Protein Solubilization, Stabilization and Crystallization

PubMed Central

Rana, Rohini R.; Gotfryd, Kamil; Rasmussen, Søren G. F.; Kruse, Andrew C.; Cho, Kyung Ho; Capaldi, Stefano; Carlsson, Emil; Kobilka, Brian; Loland, Claus J.; Gether, Ulrik; Banerjee, Surajit

2012-01-01

The development of a new class of surfactants for membrane protein manipulation, “GNG amphiphiles”, is reported. These amphiphiles display promising behavior for membrane proteins, as demonstrated recently by the high resolution structure of a sodium-pumping pyrophosphatase reported by Kellosalo et al. PMID:23165475

Design of a doubly-hydrophilic block copolypeptide that directs the formation of calcium carbonate microspheres.

PubMed

Euliss, Larken E; Trnka, Tina M; Deming, Timothy J; Stucky, Galen D

2004-08-07

The crystallization of calcium carbonate into microspheres has been accomplished using the rationally-designed, doubly-hydrophilic block copolypeptide poly(Nepsilon-2[2-(2-methoxyethoxy)ethoxy]acetyl-L-lysine)(100)-b-poly(L-aspartate sodium salt)30 as a structure-directing agent.

Pressure induced structural phase transition in solid oxidizer KClO3: A first-principles study

NASA Astrophysics Data System (ADS)

Yedukondalu, N.; Ghule, Vikas D.; Vaitheeswaran, G.

2013-05-01

High pressure behavior of potassium chlorate (KClO3) has been investigated from 0 to 10 GPa by means of first principles density functional theory calculations. The calculated ground state parameters, transition pressure, and phonon frequencies using semiempirical dispersion correction scheme are in excellent agreement with experiment. It is found that KClO3 undergoes a pressure induced first order phase transition with an associated volume collapse of 6.4% from monoclinic (P21/m) → rhombohedral (R3m) structure at 2.26 GPa, which is in good accord with experimental observation. However, the transition pressure was found to underestimate (0.11 GPa) and overestimate (3.57 GPa) using local density approximation and generalized gradient approximation functionals, respectively. Mechanical stability of both the phases is explained from the calculated single crystal elastic constants. In addition, the zone center phonon frequencies have been calculated using density functional perturbation theory at ambient as well as at high pressure and the lattice modes are found to soften under pressure between 0.6 and 1.2 GPa. The present study reveals that the observed structural phase transition leads to changes in the decomposition mechanism of KClO3 which corroborates with the experimental results.

Pressure induced structural phase transition in solid oxidizer KClO3: a first-principles study.

PubMed

Yedukondalu, N; Ghule, Vikas D; Vaitheeswaran, G

2013-05-07

High pressure behavior of potassium chlorate (KClO3) has been investigated from 0 to 10 GPa by means of first principles density functional theory calculations. The calculated ground state parameters, transition pressure, and phonon frequencies using semiempirical dispersion correction scheme are in excellent agreement with experiment. It is found that KClO3 undergoes a pressure induced first order phase transition with an associated volume collapse of 6.4% from monoclinic (P2(1)/m) → rhombohedral (R3m) structure at 2.26 GPa, which is in good accord with experimental observation. However, the transition pressure was found to underestimate (0.11 GPa) and overestimate (3.57 GPa) using local density approximation and generalized gradient approximation functionals, respectively. Mechanical stability of both the phases is explained from the calculated single crystal elastic constants. In addition, the zone center phonon frequencies have been calculated using density functional perturbation theory at ambient as well as at high pressure and the lattice modes are found to soften under pressure between 0.6 and 1.2 GPa. The present study reveals that the observed structural phase transition leads to changes in the decomposition mechanism of KClO3 which corroborates with the experimental results.

Natural chlorate in the environment: Application of a new IC-ESI/MS/MS method with a Cl18O3- internal standard

USGS Publications Warehouse

Rao, Balaji; Hatzinger, Paul B.; Böhlke, John Karl; Sturchio, Neil C.; Andraski, Brian J.; Eckardt, Frank D.; Jackson, W. Andrew

2010-01-01

A new ion chromatography electrospray tandem mass spectrometry (IC-ESI/MS/MS) method has been developed for quantification and confirmation of chlorate (ClO3−) in environmental samples. The method involves the electro-chemical generation of isotopically labeled chlorate internal standard (Cl18O3−) using 18O water (H218O). The standard was added to all samples prior to analysis thereby minimizing the matrix effects that are associated with common ions without the need for expensive sample pretreatments. The method detection limit (MDL) for ClO3− was 2 ng L−1 for a 1 mL volume sample injection. The proposed method was successfully applied to analyze ClO3− in difficult environmental samples including soil and plant leachates. The IC-ESI/MS/MS method described here was also compared to established EPA method 317.0 for ClO3− analysis. Samples collected from a variety of environments previously shown to contain natural perchlorate (ClO4−) occurrence were analyzed using the proposed method and ClO3− was found to co-occur with ClO4− at concentrations ranging from <2 ng L−1 in precipitation from Texas and Puerto Rico to >500 mg kg−1 in caliche salt deposits from the Atacama Desert in Chile. Relatively low concentrations of ClO3− in some natural groundwater samples (<0.1 μg L−1) analyzed in this work may indicate lower stability when compared to ClO4− in the subsurface. The high concentrations of ClO3− in caliches and soils (3−6 orders of magnitude greater) as compared to precipitation samples indicate that ClO3−, like ClO4−, may be atmospherically produced and deposited, then concentrated in dry soils, and is possibly a minor component in the biogeochemical cycle of chlorine.

Natural chlorate in the environment: application of a new IC-ESI/MS/MS method with a Cl¹⁸O₃-internal standard.

PubMed

Balaji Rao, Balaji Rao; Hatzinger, Paul B; Böhlke, John Karl; Sturchio, Neil C; Andraski, Brian J; Eckardt, Frank D; Jackson, W Andrew

2010-11-15

A new ion chromatography electrospray tandem mass spectrometry (IC-ESI/MS/MS) method has been developed for quantification and confirmation of chlorate (ClO₃⁻) in environmental samples. The method involves the electrochemical generation of isotopically labeled chlorate internal standard (Cl¹⁸O₃⁻) using ¹⁸O water (H₂¹⁸O) he standard was added to all samples prior to analysis thereby minimizing the matrix effects that are associated with common ions without the need for expensive sample pretreatments. The method detection limit (MDL) for ClO₃⁻ was 2 ng L⁻¹ for a 1 mL volume sample injection. The proposed method was successfully applied to analyze ClO₃⁻ in difficult environmental samples including soil and plant leachates. The IC-ESI/MS/MS method described here was also compared to established EPA method 317.0 for ClO₃⁻ analysis. Samples collected from a variety of environments previously shown to contain natural perchlorate (ClO₄⁻) occurrence were analyzed using the proposed method and ClO₃⁻ was found to co-occur with ClO₄⁻ at concentrations ranging from < 2 ng L⁻¹ in precipitation from Texas and Puerto Rico to >500 mg kg⁻¹ in caliche salt deposits from the Atacama Desert in Chile. Relatively low concentrations of ClO₃⁻ in some natural groundwater samples (0.1 µg L⁻¹) analyzed in this work may indicate lower stability when compared to ClO₄⁻ in the subsurface. The high concentrations ClO₃⁻ in caliches and soils (3-6 orders of magnitude greater) as compared to precipitation samples indicate that ClO₃⁻, like ClO₄⁻, may be atmospherically produced and deposited, then concentrated in dry soils, and is possibly a minor component in the biogeochemical cycle of chlorine.

Determination of trace selenium by solid substrate-room temperature phosphorescence enhancing method based on potassium chlorate oxidizing phenyl hydrazine-1,2-dihydroxynaphthalene-3,6-disulfonic acid system.

PubMed

Liu, Jia-Ming; Cui, Xiao-Jie; Li, Lai-Ming; Fu, Geng-Min; Lin, Shao-Xian; Yang, Min-Lan; Xu, Mei-Ying; Wu, Zhi-Qun

2007-04-01

A new method for the determination of trace selenium based on solid substrate-room temperature phosphorimetry (SS-RTP) has been established. This method was based on the fact that in HCl-KCl buffer solution, potassium chlorate could oxidize phenyl hydrazine to form chloridize diazo-ion after being heated at 100 degrees C for 20 min, and then the diazo-ion reacted with 1,2-dihydroxynaphthalene-3,6-disulfonic acid to form red azo-compound which could emit strong room temperature phosphorescence (RTP) signal on filter paper. Selenium could catalyze potassium chlorate oxidizing the reaction between phenyl hydrazine and 1,2-dihydroxynaphthalene-3,6-disulfonic acid, which caused the sharp enhancement of SS-RTP. Under the optimum condition, the relationship between the phosphorescence emission intensity (DeltaIp) and the content of selenium obeyed Beer's law when the concentration of selenium is within the range of 1.60-320 fg spot-1 (or 0.0040-0.80 ng ml-1 with a sample volume of 0.4 microl). The regression equation of working curve can be expressed as DeltaIp=13.12+0.4839CSe(IV) (fg spot-1) (n=6), with correlation coefficient r=0.9991 and a detection limit of 0.28 fg spot-1 (corresponding to a concentration range of 7.0x10(-13) g ml-1 Se(IV), n=11). After 11-fold measurement, R.S.D. were 2.8 and 3.5% for the samples containing 0.0040 and 0.80 ng ml-1 of Se(IV), respectively. This accurate and sensitive method with good repeatability has been successfully applied to the determination of trace selenium in Chinese wolfberry and egg yolk with satisfactory results. The mechanism of the enhancement of phosphorescence was also discussed.

Determination of trace selenium by solid substrate-room temperature phosphorescence enhancing method based on potassium chlorate oxidizing phenyl hydrazine-1,2-dihydroxynaphthalene-3,6-disulfonic acid system

NASA Astrophysics Data System (ADS)

Liu, Jia-Ming; Cui, Xiao-Jie; Li, Lai-Ming; Fu, Geng-Min; Lin, Shao-Xian; Yang, Min-Lan; Xu, Mei-Ying; Wu, Zhi-Qun

2007-04-01

A new method for the determination of trace selenium based on solid substrate-room temperature phosphorimetry (SS-RTP) has been established. This method was based on the fact that in HCl-KCl buffer solution, potassium chlorate could oxidize phenyl hydrazine to form chloridize diazo-ion after being heated at 100 °C for 20 min, and then the diazo-ion reacted with 1,2-dihydroxynaphthalene-3,6-disulfonic acid to form red azo-compound which could emit strong room temperature phosphorescence (RTP) signal on filter paper. Selenium could catalyze potassium chlorate oxidizing the reaction between phenyl hydrazine and 1,2-dihydroxynaphthalene-3,6-disulfonic acid, which caused the sharp enhancement of SS-RTP. Under the optimum condition, the relationship between the phosphorescence emission intensity (Δ Ip) and the content of selenium obeyed Beer's law when the concentration of selenium is within the range of 1.60-320 fg spot -1 (or 0.0040-0.80 ng ml -1 with a sample volume of 0.4 μl). The regression equation of working curve can be expressed as Δ Ip = 13.12 + 0.4839 CSe(IV) (fg spot -1) ( n = 6), with correlation coefficient r = 0.9991 and a detection limit of 0.28 fg spot -1 (corresponding to a concentration range of 7.0 × 10 -13 g ml -1 Se(IV), n = 11). After 11-fold measurement, R.S.D. were 2.8 and 3.5% for the samples containing 0.0040 and 0.80 ng ml -1 of Se(IV), respectively. This accurate and sensitive method with good repeatability has been successfully applied to the determination of trace selenium in Chinese wolfberry and egg yolk with satisfactory results. The mechanism of the enhancement of phosphorescence was also discussed.

Reduction of Chlorate by Iron Mediated Processes: Implications for Oxy-Chlorine Species on Mars and Earth

NASA Astrophysics Data System (ADS)

Brundrett, M.; Yan, W.; Jackson, W. A.

2017-12-01

Studies have confirmed the presence of chlorate (ClO3-) and perchlorate (ClO4-) in terrestrial systems, lunar regolith, Martian surface soils, and meteorites [1, 2, 4]. A roughly equimolar ratio of ClO3- : ClO4- has been observed for most systems with the only major exceptions the Antarctica dry valley soils (MDV) and Martian surface material, where the ClO3- : ClO4- ratios are significantly less than 1 [3, 4]. All known ClO4- production mechanisms produce molar ratios of ClO3-: ClO4- equal to or greater than 1 [5]. Post depositional processes may explain the potential reduction of ClO3-. The objective of this study was to determine the potential abiotic transformation of ClO3- by Fe (II)-bearing minerals, similar to known reactions between NO3- and Fe (II) minerals. The presence of iron-derived minerals has been established in the MDV, Martian soils, and chondrite meteorites. Batch experiments were conducted by reacting four Fe (II)-bearing minerals (wustite, siderite, magnetite, and green rust) with ClO3- at various pH (4.5, 6.5, 8.9). Chlorate reduction was rapid (half-life on the order of hours to days) and generally ClO3- was quantitatively converted to Cl-. Results of this study will increase our understanding of surface reactions that produced and transformed oxy-chlorine compounds on Mars elucidating past and present Martian surface conditions. The study also has implications into the understanding of the evolutionary processes that previously or currently dictate the abiotic geochemical processing of oxy-chlorine anions through terrestrial systems. [1] Jackson et al. (2015) EPSL 430, 470-476. [2] Rao et al. (2010) ES&T 44, 8429-8434. [3] Jackson et al. (2010) ES&T 44, 4869-4876. [4] Hecht et al. (2009) SCI 325, 64-67. [5] Rao et al. (2010) ES&T 44, 2961-2967.

Crystal structure of centrosymmetric 12-layer sodium-rich eudialyte

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rozenberg, K. A.; Rastsvetaeva, R. K., E-mail: rast@ns.crys.ras.ru; Verin, I. A.

2009-05-15

The structure of a new representative of the eudialyte group with the formula (Na,Sr,K){sub 18}Ca{sub 6}Zr{sub 3}Fe[Si{sub 25}O{sub 72}](OH){sub 2}Cl . H{sub 2}O from the Lovozero massif (Kola Peninsula) was studied by X-ray diffraction. The trigonal unit-cell parameters are a = 14.226 A, c = 30.339 A, sp. gr. R3-barm; the R factor is 0.045 based on 990 reflections. This sample is of interest as a sodium-rich and iron-poor mineral having a rare centrosymmetric structure, in which the M(2) site is occupied predominantly by sodium atoms. The dependence of the formation of centrosymmetric and non-centrosymmetric structures on the composition ofmore » eudialyte-group minerals was analyzed.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faham, S.; Watanabe, A.; Besserer, G.M.

Membrane transporters that use energy stored in sodium gradients to drive nutrients into cells constitute a major class of proteins. We report the crystal structure of a member of the solute sodium symporters (SSS), the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT). The -3.0 angstrom structure contains 14 transmembrane (TM) helices in an inward-facing conformation with a core structure of inverted repeats of 5 TM helices (TM2 to TM6 and TM7 to TM11). Galactose is bound in the center of the core, occluded from the outside solutions by hydrophobic residues. Surprisingly, the architecture of the core is similar to that of themore » leucine transporter (LeuT) from a different gene family. Modeling the outward-facing conformation based on the LeuT structure, in conjunction with biophysical data, provides insight into structural rearrangements for active transport.« less

Layered P2-Na 2/3 Co 1/2 Ti 1/2 O 2 as a high-performance cathode material for sodium-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabi, Noha; Doubaji, Siham; Hashimoto, Kazuki

Layered oxides are regarded as promising cathode materials for sodium-ion batteries. We present Na2/3Co1/2Ti1/2O2 as a potential new cathode material for sodium-ion batteries. The crystal features and morphology of the pristine powder were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The cathode material is evaluated in galvanostatic charge-discharge and galvanostatic intermittent titration tests, as well as ex-situ X-ray diffraction analysis. Synthesized by a high-temperature solid state reaction, Na2/3Co1/2Ti1/2O2 crystallizes in P2-type structure with P6(3)/mmc space group. The material presents reversible electrochemical behavior and delivers a specific discharge capacity of 100 mAh g(-1) when tested in Na halfmore » cells between 2.0 and 4.2 V (vs. Na+/Na), with capacity retention of 98% after 50 cycles. Furthermore, the electrochemical cycling of this titanium-containing material evidenced a reduction of the potential jumps recorded in the NaxCoO2 parent phase, revealing a positive impact of Ti substitution for Co. The ex-situ XRD measurements confirmed the reversibility and stability of the material. No structural changes were observed in the XRD patterns, and the P2-type structure was stable during the charge/discharge process between 2.0 and 4.2 V vs. Na+/Na. These outcomes will contribute to the progress of developing low cost electrode materials for sodium-ion batteries. (C) 2017 Elsevier B.V. All rights reserved.« less

Cloning, expression, purification, crystallization and preliminary X-ray crystallographic analysis of bacterioferritin A from Mycobacterium tuberculosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Vibha; Gupta, Rakesh K.; Ram Lal Anand College, University of Delhi, Benito Juarez Road, New Delhi 110021

2008-05-01

The cloning, purification and crystallization of a bacterioferritin from M. tuberculosis together with preliminary X-ray characterization of its crystals are reported. Bacterioferritins (Bfrs) comprise a subfamily of the ferritin superfamily of proteins that play an important role in bacterial iron storage and homeostasis. Bacterioferritins differ from ferritins in that they have additional noncovalently bound haem groups. To assess the physiological role of this subfamily of ferritins, a greater understanding of the structural details of bacterioferritins from various sources is required. The gene encoding bacterioferritin A (BfrA) from Mycobacterium tuberculosis was cloned and expressed in Escherichia coli. The recombinant protein productmore » was purified by affinity chromatography on a Strep-Tactin column and crystallized with sodium chloride as a precipitant at pH 8.0 using the vapour-diffusion technique. The crystals diffracted to 2.1 Å resolution and belonged to space group P4{sub 2}, with unit-cell parameters a = 123.0, b = 123.0, c = 174.6 Å.« less

Crystallization and preliminary X-ray diffraction analysis of ScrY, a specific bacterial outer membrane porin.

PubMed

Forst, D; Schülein, K; Wacker, T; Diederichs, K; Kreutz, W; Benz, R; Welte, W

1993-01-05

The sucrose-specific outer membrane porin ScrY of Salmonella typhimurium was isolated from Escherichia coli K-12 strain KS 26 containing the plasmid pPSO112. The protein was purified to homogeneity by differential extraction of the cell envelope in the presence of the detergents sodium dodecyl sulfate and lauryl (dimethyl)-amine oxide (LDAO). The porin had apparent molecular weights of 58 kDa and 120 kDa for the monomer and for the trimer, respectively, on SDS/PAGE. The purified trimers were crystallized using poly(ethylene glycol) 2000 and the detergents octylglucoside (OG) and hexyl-(dimethyl)-amine oxide (C6DAO). X-ray diffraction of the crystals showed reflections to 2.3 A. The space group of the crystals was R3 and the lattice constants of the hexagonal axes were a = b = 112.85 A and c = 149.9 A. The crystal volume per unit of protein molecular weight was 3.47 A3/Da.

RH-temperature phase diagrams of hydrate forming deliquescent crystalline ingredients.

PubMed

Allan, Matthew; Mauer, Lisa J

2017-12-01

Several common deliquescent crystalline food ingredients (including glucose and citric acid) are capable of forming crystal hydrate structures. The propensity of such crystals to hydrate/dehydrate or deliquesce is dependent on the environmental temperature and relative humidity (RH). As an anhydrous crystal converts to a crystal hydrate, water molecules internalize into the crystal structure resulting in different physical properties. Deliquescence is a solid-to-solution phase transformation. RH-temperature phase diagrams of the food ingredients alpha-d-glucose and citric acid, along with sodium sulfate, were produced using established and newly developed methods. Each phase diagram included hydrate and anhydrate deliquescence boundaries, the anhydrate-hydrate phase boundary, and the peritectic temperature (above which the hydrate was no longer stable). This is the first report of RH-temperature phase diagrams of glucose and citric acid, information which is beneficial for selecting storage and processing conditions to promote or avoid hydrate formation or loss and/or deliquescence. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of nanometer-sized sodalite without adding organic additives.

PubMed

Fan, Wei; Morozumi, Kazumasa; Kimura, Riichiro; Yokoi, Toshiyuki; Okubo, Tatsuya

2008-06-01

Aggregates (80 nm) of sodalite nanocrystals with crystallite sizes ranging from 20 to 40 nm have been synthesized from a sodium aluminosilicate solution at low temperature, without adding any organic additives, while paying attention to the key factors for the synthesis of nanosized zeolite crystals. The physical properties of nanosized sodalite crystals were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, 29Si solid-state magic-angle spinning (MAS) NMR, and N2 adsorption. As expected, the external surface area of nanosized sodalite crystals is significantly increased compared with that of microsized sodalite crystals. The size of synthesized sodalite crystals can be controlled from 20 nm to 10 microm. It is found that the preparation of a homogeneous aluminosilicate solution followed by the formation of an aluminosilicate hard gel by adjusting the initial composition, for example, SiO2/Al2O3 and Na2O/H2O ratios, is critical for synthesis.

Cloning, expression, crystallization and preliminary X-ray data analysis of norcoclaurine synthase from Thalictrum flavum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasquo, Alessandra; Bonamore, Alessandra; Franceschini, Stefano

The cloning, expression, crystallization and preliminary X-ray data analysis of norcoclaurine synthase from T. flavum, a protein which catalyzes the first committed step in the biosynthesis of benzylisoquinoline alkaloids, are reported. Norcoclaurine synthase (NCS) catalyzes the condensation of 3,4-dihydroxyphenylethylamine (dopamine) and 4-hydroxyphenylacetaldehyde (4-HPAA) as the first committed step in the biosynthesis of benzylisoquinoline alkaloids in plants. The protein was cloned, expressed and purified. Crystals were obtained at 294 K by the hanging-drop vapour-diffusion method using ammonium sulfate and sodium chloride as precipitant agents and diffract to better than 3.0 Å resolution using a synchrotron-radiation source. The crystals belong to themore » trigonal space group P3{sub 1}21, with unit-cell parameters a = b = 86.31, c = 118.36 Å. A selenomethionine derivative was overexpressed, purified and crystallized in the same space group. A complete MAD data set was collected at 2.7 Å resolution. The model is under construction.« less

Crystallization and halide phasing of the C-terminal domain of human KIN17

PubMed Central

le Maire, Albane; Schiltz, Marc; Braud, Sandrine; Gondry, Muriel; Charbonnier, Jean-Baptiste; Zinn-Justin, Sophie; Stura, Enrico

2006-01-01

Here, the crystallization and initial phasing of the C-terminal domain of human KIN17, a 45 kDa protein mainly expressed in response to ionizing radiation and overexpressed in certain tumour cell lines, are reported. Crystals diffracting to 1.4 Å resolution were obtained from 10% ethylene glycol, 27% PEG 6000, 500 mM LiCl and 100 mM sodium acetate pH 6.3 in space group P212121, with unit-cell parameters a = 45.75, b = 46.31, c = 60.80 Å and one molecule in the asymmetric unit. Since this domain has a basic pI, heavy-atom derivatives were obtained by soaking the crystals with negatively charged ions such as tungstate and iodine. The replacement of LiCl by KI in the cryosolution allowed the determination of phases from iodide ions to give an interpretable electron-density map. PMID:16511313

Purification, crystallization and preliminary crystallographic analysis of Est25: a ketoprofen-specific hormone-sensitive lipase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, SeungBum; Joo, Sangbum; Yoon, Hyun C.

2007-07-01

Est25, a ketoprofen-specific hormone-sensitive lipase from a metagenomic library, was crystallized and diffraction data were collected to 1.49 Å resolution. Ketoprofen, a nonsteroidal anti-inflammatory drug, inhibits the synthesis of prostaglandin. A novel hydrolase (Est25) with high ketoprofen specificity has previously been identified using a metagenomic library from environmental samples. Recombinant Est25 protein with a histidine tag at the N-terminus was expressed in Escherichia coli and purified in a homogenous form. Est25 was crystallized from 2.4 M sodium malonate pH 7.0 and X-ray diffraction data were collected to 1.49 Å using synchrotron radiation. The crystals belong to the monoclinic space groupmore » C2, with unit-cell parameters a = 197.8, b = 95.2, c = 99.4 Å, β = 97.1°.« less

Protein crystal growth in low gravity

NASA Technical Reports Server (NTRS)

Feigelson, Robert S.

1987-01-01

The solubility and growth mechanism of canavalin were studied, and the applicability of the Schlieren technique to protein crystal growth was investigated. Canavalin which may be crystallized from a basic solution by the addition of hydrogen (H+) ions was shown to have normal solubility characteristics over the range of temperatures (5 to 25 C) and pH (5 to 7.5) studied. The solubility data combined with growth rate data gathered from the seeded growth of canavalin crystals indicated that the growth mechanism at high supersaturation ratios (>1.28) is screw dislocation like. A Schlieren apparatus was constructed and flow patterns were observed in Rochelle salt (sodium potassium tartrate), lysozyme, and canavalin. The critical parameters were identified as the change in density with concentration (dp/dc) and the change in index of refraction with concentration (dn/dc). Some of these values were measured for the materials listed.

Study of ceramic products and processing techniques in space. [using computerized simulation

NASA Technical Reports Server (NTRS)

Markworth, A. J.; Oldfield, W.

1974-01-01

An analysis of the solidification kinetics of beta alumina in a zero-gravity environment was carried out, using computer-simulation techniques, in order to assess the feasibility of producing high-quality single crystals of this material in space. The two coupled transport processes included were movement of the solid-liquid interface and diffusion of sodium atoms in the melt. Results of the simulation indicate that appreciable crystal-growth rates can be attained in space. Considerations were also made of the advantages offered by high-quality single crystals of beta alumina for use as a solid electrolyte; these clearly indicate that space-grown materials are superior in many respects to analogous terrestrially-grown crystals. Likewise, economic considerations, based on the rapidly expanding technological applications for beta alumina and related fast ionic conductors, reveal that the many superior qualities of space-grown material justify the added expense and experimental detail associated with space processing.

The role of sulfates on antifreeze protein activity.

PubMed

Meister, Konrad; Duman, John G; Xu, Yao; DeVries, Arthur L; Leitner, David M; Havenith, Martina

2014-07-17

In the present study, we have investigated the effect of sodium sulfate (Na2SO4) buffer on the antifreeze activity of DAFP-1, the primary AFP in the hemolymph of the beetle Dendroides canadensis. In contrast to previous studies, we found evidence that sodium sulfate does not suppress antifreeze activity of DAFP-1. Terahertz absorption spectroscopy (THz) studies were combined with molecular dynamics (MD) simulations to investigate the change in collective hydrogen bond dynamics in the vicinity of the AFP upon addition of sodium sulfate. The MD simulations revealed that the gradient of H-bond dynamics toward the ice-binding site is even more pronounced when adding sodium sulfate: The cosolute dramatically slows the hydrogen bond dynamics on the ice-binding plane of DAFP-1, whereas it has a more modest effect in the vicinity of other parts of the protein. These theoretical predictions are in agreement with the experimentally observed increase in THz absorption for solvated DAFP-1 upon addition of sodium sulfate. These studies support our previously postulated mechanism for AF activity, with a preferred ice binding by threonine on nanoice crystals which is supported by a long-range effect on hydrogen bond dynamics.

Two-Fold Anisotropy Governs Morphological Evolution and Stress Generation in Sodiated Black Phosphorus for Sodium Ion Batteries.

PubMed

Chen, Tianwu; Zhao, Peng; Guo, Xu; Zhang, Sulin

2017-04-12

Phosphorus represents a promising anode material for sodium ion batteries owing to its extremely high theoretical capacity. Recent in situ transmission electron microscopy studies evidenced anisotropic swelling in sodiated black phosphorus, which may find an origin from the two intrinsic anisotropic properties inherent to the layered structure of black phosphorus: sodium diffusional directionality and insertion strain anisotropy. To understand the morphological evolution and stress generation in sodiated black phosphorus, we develop a chemo-mechanical model by incorporating the intrinsic anisotropic properties into the large elasto-plastic deformation. Our modeling results reveal that the apparent morphological evolution in sodiated black phosphorus is critically controlled by the coupled effect of the two intrinsic anisotropic properties. In particular, sodium diffusional directionality generates sharp interphases along the [010] and [001] directions, which constrain anisotropic development of the insertion strain. The coupled effect renders distinctive stress-generation and fracture mechanisms when sodiation starts from different crystal facets. In addition to providing a powerful modeling framework for sodiation and lithiation of layered structures, our findings shed significant light on the sodiation-induced chemo-mechanical degradation of black phosphorus as a promising anode for the next-generation sodium ion batteries.

Monitored Natural Attenuation of Perchlorate in Groundwater

DTIC Science & Technology

2010-09-01

has been used for industrial purposes, such as fireworks manufacturing, munitions production, pesticide production, and research and manufacturing of...Field Services Division, Washington, DC, August 2006. Hunter, W.J. 2002. Bioremediation of Chlorate or Perchlorate Contaminated Water Using ...5.2.2.1 A-82 Pump-and-Treat System ................................................ 20 5.2.2.2 In Situ Bioremediation Pilot Test

Crystallization and X-ray diffraction analysis of the RNA primer/promoter-binding domain of influenza A virus RNA-dependent RNA polymerase PB2

PubMed Central

Kuzuhara, Takashi; Kise, Daisuke; Yoshida, Hiroko; Horita, Takahiro; Murazaki, Yoshimi; Utsunomiya, Hiroko; Tsuge, Hideaki

2009-01-01

The C-terminal domain protein (amino-acid residues 535–759) of the PB2 subunit of the RNA-dependent RNA polymerase from the highly pathogenic influenza A virus was expressed as a soluble protein in Escherichia coli and crystallized using sodium formate as a precipitant. Data sets were collected from crystals of native and selenomethionine-substituted protein on the KEK NW12 beamline at the Photon Factory and the crystals diffracted to a maximum resolution of 2.44 Å for the SeMet-derivative crystal. The native crystals were found to belong to space group P3221, with unit-cell parameters a = b = 52.5, c = 156.3 Å. The Matthews value (V M) was 2.7 Å3 Da−1, assuming the presence of one molecule in the asymmetric unit. The SeMet-derivative crystals were found to belong to the same space group, with unit-cell parameters a = b = 52.6, c = 156.4 Å. Attempts are being made to solve the structure by multi-wavelength anomalous dispersion phasing. PMID:19194006

Ion Transport and Precipitation Kinetics as Key Aspects of Stress Generation on Pore Walls Induced by Salt Crystallization

NASA Astrophysics Data System (ADS)

Naillon, A.; Joseph, P.; Prat, M.

2018-01-01

The stress generation on pore walls due to the growth of a sodium chloride crystal in a confined aqueous solution is studied from evaporation experiments in microfluidic channels in conjunction with numerical computations of crystal growth. The study indicates that the stress buildup on the pore walls is a highly transient process taking place over a very short period of time (in less than 1 s in our experiments). The analysis makes clear that what matters for the stress generation is not the maximum supersaturation at the onset of the crystal growth but the supersaturation at the interface between the solution and the crystal when the latter is about to be confined between the pore walls. The stress generation is summarized in a simple stress diagram involving the pore aspect ratio and the Damkhöler number characterizing the competition between the precipitation reaction kinetics and the ion transport towards the growing crystal. This opens up the route for a better understanding of the damage of porous materials induced by salt crystallization, an important issue in Earth sciences, reservoir engineering, and civil engineering.

Quality by design in formulation and process development for a freeze-dried, small molecule parenteral product: a case study.

PubMed

Mockus, Linas N; Paul, Timothy W; Pease, Nathan A; Harper, Nancy J; Basu, Prabir K; Oslos, Elizabeth A; Sacha, Gregory A; Kuu, Wei Y; Hardwick, Lisa M; Karty, Jacquelyn J; Pikal, Michael J; Hee, Eun; Khan, Mansoor A; Nail, Steven L

2011-01-01

A case study has been developed to illustrate one way of incorporating a Quality by Design approach into formulation and process development for a small molecule, freeze-dried parenteral product. Sodium ethacrynate was chosen as the model compound. Principal degradation products of sodium ethacrynate result from hydrolysis of the unsaturated ketone in aqueous solution, and dimer formation from a Diels-Alder condensation in the freeze-dried solid state. When the drug crystallizes in a frozen solution, the eutectic melting temperature is above -5°C. Crystallization in the frozen system is affected by pH in the range of pH 6-8 and buffer concentration in the range of 5-50 mM, where higher pH and lower buffer concentration favor crystallization. Physical state of the drug is critical to solid state stability, given the relative instability of amorphous drug. Stability was shown to vary considerably over the ranges of pH and buffer concentration examined, and vial-to-vial variability in degree of crystallinity is a potential concern. The formulation design space was constructed in terms of pH and drug concentration, and assuming a constant 5 mM concentration of buffer. The process design space is constructed to take into account limitations on the process imposed by the product and by equipment capability.

The nuclear radiation monitor for the Spacelab/Shuttle

NASA Technical Reports Server (NTRS)

Fishman, G. J.

1978-01-01

A 5 inch by 5 inch diameter sodium iodide scintillation crystal, viewed by a 5 inch photomultiplier was designed to be mounted near the center of the shuttle payload bay to quantitatively measure the neutron and gamma ray environment during the second Spacelab mission. The expected energy resolution is 8% FWHM at 662 keV. The detector will operate in an energy range from 0.1 to 20 MeV. A charged anticoincidence shield consisting of a 1 cm thick plastic scintillator viewed by three 2 inch photomultiplier tubes, covers the crystal detector which has nearly omnidirectional response.

Effect of temperature on the formation of creep substructure in sodium chloride single crystals

NASA Technical Reports Server (NTRS)

Raj, Sai V.; Pharr, George M.

1992-01-01

The effect of temperature on the substructure morphology and the cell and subgrain size was investigated experimentally in NaCl single crystals under creep in the temperature range 573-873 K. It is found that the effect of temperature on the cell and subgrain sizes is weak in comparison with the effect of stress. However, there was a qualitative change in the substructure morphology with temperature, with the cells and subgrains better defined at higher temperatures. The volume fraction of the cell boundaries decreased with increasing temperature, thereby indicating a refinement of the microstructure at higher temperatures.

The Effect of Solution Conditions on the Nucleation Kinetics of Tetragonal Lysozyme Crystals

NASA Technical Reports Server (NTRS)

Judge, Russell A.; Baird, James K.; Pusey, Marc L.

1998-01-01

An understanding of protein crystal nucleation rates and the effect of solution conditions upon them, is fundamental to the preparation of protein crystals of the desired size and shape for X-ray diffraction analysis. The ability to predict the effect of supersaturation, temperature, pH and precipitant concentration on the number and size of crystals formed is of great benefit in the pursuit of protein structure analysis. In this study we experimentally examine the effect of supersaturation, temperature, pH and sodium chloride concentration on the nucleation rate of tetragonal chicken egg white lysozyme crystals. In order to do this batch crystallization plates were prepared at given solution concentrations and incubated at three different temperatures over the period of one week. The number of crystals per well with their size and dimensions were recorded and correlated against solution conditions. Duplicate experiments indicate the reproducibility of the technique. Although it is well known that crystal numbers increase with increasing supersaturation, large changes in crystal number were also correlated against solution conditions of temperature, pH and salt concentration over the same supersaturation ranges. Analysis of these results enhance our understanding of the effect of solution conditions such as the dramatic effect that small changes in charge and ionic strength can have on the number of tetragonal lysozyme crystals that form and grow in solution.

Investigating Dissolution and Precipitation Phenomena with a Smartphone Microscope

ERIC Educational Resources Information Center

Lumetta, Gregg J.; Arcia, Edgar

2016-01-01

A novel smartphone microscope can be used to observe the dissolution and crystallization of sodium chloride at a microscopic level. Observation of these seemingly simple phenomena through the microscope at 100× magnification can actually reveal some surprising behavior. These experiments offer the opportunity to discuss some basic concepts such as…

Tested Demonstrations: Rossini, William Tell and the Iodine Clock Reaction: A Lecture Demonstration.

ERIC Educational Resources Information Center

Brice, L. K.; Gilbert, George L., Ed.

1980-01-01

Three demonstrations are described: (1) a variation of the iodine clock reaction in which a cassette tape recording of the William Tell Overture accompanies color changes as solutions are mixed; (2) a crystallization demonstration using sodium acetate; and (3) lecture-demonstrations creating colored colloidal dispersions from clear solutions. (CS)

New iron-based mixed-polyanion cathodes for lithium and sodium rechargeable batteries: combined first principles calculations and experimental study.

PubMed

Kim, Hyungsub; Park, Inchul; Seo, Dong-Hwa; Lee, Seongsu; Kim, Sung-Wook; Kwon, Woo Jun; Park, Young-Uk; Kim, Chul Sung; Jeon, Seokwoo; Kang, Kisuk

2012-06-27

New iron-based mixed-polyanion compounds Li(x)Na(4-x)Fe(3)(PO(4))(2)(P(2)O(7)) (x = 0-3) were synthesized, and their crystal structures were determined. The new compounds contained three-dimensional (3D)sodium/lithium paths supported by P(2)O(7) pillars in the crystal. First principles calculations identified the complex 3D paths with their activation barriers and revealed them as fast ionic conductors. The reversible electrode operation was found in both Li and Na cells with capacities of one-electron reaction per Fe atom, 140 and 129 mAh g(-1), respectively. The redox potential of each phase was ∼3.4 V (vs Li) for the Li-ion cell and ∼3.2 V (vs Na) for the Na-ion cell. The properties of high power, small volume change, and high thermal stability were also recognized, presenting this new compound as a potential competitor to other iron-based electrodes such as Li(2)FeP(2)O(7), Li(2)FePO(4)F, and LiFePO(4).

Synthesis and characterization of sodium vanadium oxide gels: the effects of water (n) and sodium (x) content on the electrochemistry of Na(x)V2O5·nH2O.

PubMed

Lee, Chia-Ying; Marschilok, Amy C; Subramanian, Aditya; Takeuchi, Kenneth J; Takeuchi, Esther S

2011-10-28

Sodium vanadium oxide gels, Na(x)V(2)O(5)·nH(2)O, of varying sodium content (0.12 < x < 0.32) were prepared by careful control of an ion exchange process. The water content (0.23 > n > 0.01) and interlayer spacing were found to be inversely proportional to the sodium level (x), thus control of sodium (x) content provided a direct, chimie douce approach for control of hydration level (n) and interlayer spacing, without the need for high temperature treatment to affect dehydration. Notably, the use of high temperatures to modify hydration levels can result in crystallization and collapse of the interlayer structure, highlighting the distinct advantage of our novel chimie douce synthesis strategy. Subsequent to synthesis and characterization, results from an electrochemical study of a series of Na(x)V(2)O(5)·nH(2)O samples highlight the significant impact of interlayer water on delivered capacity of the layered materials. Specifically, the sodium vanadium oxide gels with higher sodium content and lower water content provided higher capacities in lithium based cells, where capacity delivered to 2.0 V under C/20 discharge ranged from 170 mAh/g for Na(0.12)V(2)O(5)·0.23H(2)O to 300 mAh/g for Na(0.32)V(2)O(5)·0.01H(2)O. The capacity differences were maintained as the cells were cycled. This journal is © the Owner Societies 2011

Melt crystallization of bisphenol A polycarbonate in PC/zinc sulfonated polystyrene ionomer blend

NASA Astrophysics Data System (ADS)

Xu, Liang

The effects of zinc sulfonated polystyrene ionomer (ZnSPS) on the melt crystallization of bisphenol A polycarbonate (PC) were investigated. Melt crystallization of pure PC is extremely slow due to its rigid chain. In the blend of PC and ZnSPS (PC-ZnSPS), the melt crystallization rate of PC can be enhanced. DSC was used to study the crystallization kinetics of PC in PC-ZnSPS blend. The crystallization of PC at 190°C increased in both partially miscible and miscible blends with ZnSPS. For PC-ZnSPS blend with same PC composition as 80%, the crystallization rate was affected by the sulfonation level of ZnSPS. The induction time of crystallization for a partially miscible blend PC-ZnSPS9.98 (80/20) was 40 minutes, and the crystallization reaches 27% crystallinity within 14 hrs. The induction time for pure PC with the same thermal history was more than 24 hrs. The crystal structure of PC crystal formed in PC-ZnSPS blend was studied by WAXD, which showed no difference from the reported WAXD pattern for pure PC. Molecular weight change of PC was found during the thermal annealing of PC-ZnSPS blend at 190°C, but molecular weight alone cannot explain the change of crystallization rate of PC in PC-ZnSPS blend. Discussion was made to address the mechanisms that are responsible for the crystallization rate enhancement of PC in PC-ZnSPS blend. In order to understand and elucidate the reason for the molecular weight change of PC in PC-ZnSPS blend and its effect on the crystallization of PC, TG, GPC and GC-MS were used to investigate the stability of PC-ZnSPS blend and mixtures of PC with sodium tosylate (NaTS), zinc tosylate (ZnTS) and sodium benzoate (NaBZ). ZnSPS, NaTS and ZnTS undergo desulfonation of the sulfonate group at temperatures above 350°C. The desulfonation process can destabilize PC and lower the maximum mass loss rate temperature of PC for more than 70°C. NaTS, ZnTS and NaBZ have quite different effect on the thermal stability of PC at temperatures below 250°C. NaBZ can significantly degrade PC both at 190°C and 250°C. PC does not show any molecular weight (M w) change in the presence of NaTS at 250°C and 190°C for up to 1hr and 16 hrs respectively. ZnTS can also cause Mw change of PC at 250°C and 190°C, but the changing of Mw of PC in the presence of ZnTS is less than that in the presence of NaBZ. The reason for the molecular weight change of PC in PC-ZnSPS blend can be explained based on Davis's ionic ester exchange reaction mechanism.

Electronic and structural transitions in dense liquid sodium.

PubMed

Raty, Jean-Yves; Schwegler, Eric; Bonev, Stanimir A

2007-09-27

At ambient conditions, the light alkali metals are free-electron-like crystals with a highly symmetric structure. However, they were found recently to exhibit unexpected complexity under pressure. It was predicted from theory--and later confirmed by experiment--that lithium and sodium undergo a sequence of symmetry-breaking transitions, driven by a Peierls mechanism, at high pressures. Measurements of the sodium melting curve have subsequently revealed an unprecedented (and still unexplained) pressure-induced drop in melting temperature from 1,000 K at 30 GPa down to room temperature at 120 GPa. Here we report results from ab initio calculations that explain the unusual melting behaviour in dense sodium. We show that molten sodium undergoes a series of pressure-induced structural and electronic transitions, analogous to those observed in solid sodium but commencing at much lower pressure in the presence of liquid disorder. As pressure is increased, liquid sodium initially evolves by assuming a more compact local structure. However, a transition to a lower-coordinated liquid takes place at a pressure of around 65 GPa, accompanied by a threefold drop in electrical conductivity. This transition is driven by the opening of a pseudogap, at the Fermi level, in the electronic density of states--an effect that has not hitherto been observed in a liquid metal. The lower-coordinated liquid emerges at high temperatures and above the stability region of a close-packed free-electron-like metal. We predict that similar exotic behaviour is possible in other materials as well.

Optimized expression and purification of NavAb provide the structural insight into the voltage dependence.

PubMed

Irie, Katsumasa; Haga, Yukari; Shimomura, Takushi; Fujiyoshi, Yoshinori

2018-01-01

Voltage-gated sodium channels are crucial for electro-signalling in living systems. Analysis of the molecular mechanism requires both fine electrophysiological evaluation and high-resolution channel structures. Here, we optimized a dual expression system of NavAb, which is a well-established standard of prokaryotic voltage-gated sodium channels, for E. coli and insect cells using a single plasmid vector to analyse high-resolution protein structures and measure large ionic currents. Using this expression system, we evaluated the voltage dependence and determined the crystal structures of NavAb wild-type and two mutants, E32Q and N49K, whose voltage dependence were positively shifted and essential interactions were lost in voltage sensor domain. The structural and functional comparison elucidated the molecular mechanisms of the voltage dependence of prokaryotic voltage-gated sodium channels. © 2017 Federation of European Biochemical Societies.

Fibrillar films obtained from sodium soap fibers and polyelectrolyte multilayers.

PubMed

Zawko, Scott A; Schmidt, Christine E

2011-08-01

An objective of tissue engineering is to create synthetic polymer scaffolds with a fibrillar microstructure similar to the extracellular matrix. Here, we present a novel method for creating polymer fibers using the layer-by-layer method and sacrificial templates composed of sodium soap fibers. Soap fibers were prepared from neutralized fatty acids using a sodium chloride crystal dissolution method. Polyelectrolyte multilayers (PEMs) of polystyrene sulfonate and polyallylamine hydrochloride were deposited onto the soap fibers, crosslinked with glutaraldehyde, and then the soap fibers were leached with warm water and ethanol. The morphology of the resulting PEM structures was a dense network of fibers surrounded by a nonfibrillar matrix. Microscopy revealed that the PEM fibers were solid structures, presumably composed of polyelectrolytes complexed with residual fatty acids. These fibrillar PEM films were found to support the attachment of human dermal fibroblasts. Copyright © 2011 Wiley Periodicals, Inc.

Micellar-shape anisometry near isotropic-liquid-crystal phase transitions

NASA Astrophysics Data System (ADS)

Itri, R.; Amaral, L. Q.

1993-04-01

Micellar phases of the sodium dodecyl (lauryl) sulfate (SLS)-water-decanol system have been studied by x-ray scattering in the isotropic (I) phase, with emphasis on the I-->hexagonal (Hα) and I-->nematic-cylindrical (Nc) lyotropic liquid-crystal phase transitions. Analysis of the scattering curves is made through modeling of the product P(q)S(q), where P(q) is the micellar form factor and S(q) is the intermicellar interference function, calculated from screened Coulombic repulsion in a mean spherical approximation. Results show that micelles grow more by decanol addition near the I-->Nc transition (anisometry ν~=3) than by increased amphiphile concentration in the binary system near the I-->Hα phase transition (ν~=2.4). These results compare well with recent theories for isotropic-liquid-crystal phase transitions.

Cloning, purification, crystallization and preliminary X-ray crystallographic analysis of SET/TAF-Iß δN from Homo sapiens.

PubMed

Xu, Zhen; Yang, Weili; Shi, Nuo; Gao, Yongxiang; Teng, Maikun; Niu, Liwen

2010-08-01

The histone chaperone SET encoded by the SET gene, which is also known as template-activating factor Iß (TAF-Iß), is a multifunctional molecule that is involved in many biological phenomena such as histone binding, nucleosome assembly, chromatin remodelling, replication, transcription and apoptosis. A truncated SET/TAF-Iß ΔN protein that lacked the first 22 residues of the N-terminus but contained the C-terminal acidic domain and an additional His6 tag at the C-terminus was overexpressed in Escherichia coli and crystallized by the hanging-drop vapour-diffusion method using sodium acetate as precipitant at 283 K. The crystals diffracted to 2.7 A resolution and belonged to space group P4(3)2(1)2.

Multiangular Rod-Shaped Na0.44MnO2 as Cathode Materials with High Rate and Long Life for Sodium-Ion Batteries.

PubMed

Liu, Qiannan; Hu, Zhe; Chen, Mingzhe; Gu, Qinfen; Dou, Yuhai; Sun, Ziqi; Chou, Shulei; Dou, Shi Xue

2017-02-01

The tunnel-structured Na 0.44 MnO 2 is considered as a promising cathode material for sodium-ion batteries because of its unique three-dimensional crystal structure. Multiangular rod-shaped Na 0.44 MnO 2 have been first synthesized via a reverse microemulsion method and investigated as high-rate and long-life cathode materials for Na-ion batteries. The microstructure and composition of prepared Na 0.44 MnO 2 is highly related to the sintering temperature. This structure with suitable size increases the contact area between the material and the electrolyte and guarantees fast sodium-ion diffusion. The rods prepared at 850 °C maintain specific capacity of 72.8 mA h g -1 and capacity retention of 99.6% after 2000 cycles at a high current density of 1000 mA g -1 . The as-designed multiangular Na 0.44 MnO 2 provides new insight into the development of tunnel-type electrode materials and their application in rechargeable sodium-ion batteries.

Structure of 1:1 complex of 1-naphthylmethyl ester of monensin A with sodium perchlorate studied by X-ray, FT-IR and ab initio methods

NASA Astrophysics Data System (ADS)

Huczyński, Adam; Janczak, Jan; Brzezinski, Bogumil

2012-12-01

A new crystalline complex formed between 1-naphthylmethyl ester of the naturally occurring antibiotic - monensin A (MON8) with sodium perchlorate has been obtained and studied using X-ray crystallography and FT-IR spectroscopy. The X-ray data of the complex show that MON8 forms a pseudo-cyclic structure stabilised by one weak intramolecular hydrogen bond and the sodium cation co-ordinated by two oxygen atoms of hydroxyl groups and four etheric oxygen atoms in the hydrophilic sphere. Within this structure the oxygen atoms of the ester groups are not involved in the coordination of sodium cation. In contrast to the solid state structure of the complex, in acetonitrile solution an equilibrium between two structures, in which the oxygen atom of the carbonyl ester group is either involved or not involved in the complexation of the sodium cation, is found. In acetonitrile this equilibrium is shifted towards the latter structure i.e. the structure existing in the solid state. The gas-phase structure of [MON8sbnd Na]+ cation as shown the ab initio MO calculations is comparable with the crystal one. Three-dimensional molecular electrostatic potential calculated for the neutral MON8 and [MON8sbnd Na]+ molecules is helpful for understanding the structural aspects of the sodium complex formation.

Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding.

PubMed

Hüttel, Wolfgang; Spencer, Jonathan B; Leadlay, Peter F

2014-01-01

Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a lipophilic backbone can form strong ionophoric complexes with certain metal cations. In this work, we demonstrate for monensin biosynthesis that, as well as ether formation, a late-stage hydroxylation step is crucial for the correct formation of the sodium monensin complex. We have investigated the last two steps in monensin biosynthesis, namely hydroxylation catalysed by the P450 monooxygenase MonD and O-methylation catalysed by the methyl-transferase MonE. The corresponding genes were deleted in-frame in a monensin-overproducing strain of Streptomyces cinnamonensis. The mutants produced the expected monensin derivatives in excellent yields (ΔmonD: 1.13 g L(-1) dehydroxymonensin; ΔmonE: 0.50 g L(-1) demethylmonensin; and double mutant ΔmonDΔmonE: 0.34 g L(-1) dehydroxydemethylmonensin). Single crystals were obtained from purified fractions of dehydroxymonensin and demethylmonensin. X-ray structure analysis revealed that the conformation of sodium dimethylmonensin is very similar to that of sodium monensin. In contrast, the coordination of the sodium ion is significantly different in the sodium dehydroxymonensin complex. This shows that the final constitution of the sodium monensin complex requires this tailoring step as well as polyether formation.

Tissue-culture investigations into mechanisms of biomass enhancement. Annual report, June 1984-July 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nabors, M.W.

1985-07-01

The cost effectiveness of biogas production can be considerably improved by producing cultivars of sorghum and Napier grass with increased biomass and tolerance to common soil stresses such as salinity and drought. In addition, increased fertilizer efficiency of plants used for biomass is also desired. Tissue-culture methodologies provide a means for generating improved sorghum and Napier grass cultivars and for selecting cells and plants with tolerance to salinity, drought, and low levels of applied nitrogen fertilizer. To this end, tissue cultures of sorghum and Napier grass were established. Media were devised to enhance high-frequency, long-term plant production from these cultures.more » Existing methods were considerably improved and the first plant regeneration techniques from callus cultures of sweet sorghum were devised. Over 1000 plants were regenerated from callus cultures during the first year. These are being used in biomass production assays. Tissue culture selection for salt tolerance has been initiated using high levels of NaCl or hydroxyproline in the medium. Sodium chloride stress represents direct selection; hydroxyproline stress selects cells with increased levels of proline, an amino acid known to be associated with salt tolerance. Selection for cell variants efficient in reducing nitrate are planned; cells will be grown in the presence of chlorate, a nitrate analogue. Selections are carried out on either solid or liquid media. Cell suspension systems, allowing more efficient selection, are being developed for all cultivars under study.« less

Heparan Sulfate and Chondroitin Sulfate Glycosaminoglycans Are Targeted by Bleomycin in Cancer Cells.

PubMed

Li, Xiulian; Lan, Ying; He, Yanli; Liu, Yong; Luo, Heng; Yu, Haibo; Song, Ni; Ren, Sumei; Liu, Tianwei; Hao, Cui; Guo, Yunliang; Zhang, Lijuan

2017-01-01

Bleomycin is a clinically used anti-cancer drug that produces DNA breaks once inside of cells. However, bleomycin is a positively charged molecule and cannot get inside of cells by free diffusion. We previously reported that the cell surface negatively charged glycosaminoglycans (GAGs) may be involved in the cellular uptake of bleomycin. We also observed that a class of positively charged small molecules has Golgi localization once inside of the cells. We therefore hypothesized that bleomycin might perturb Golgi-operated GAG biosynthesis. We used stable isotope labeling coupled with LC/MS analysis of GAG disaccharides simultaneously from bleomycin-treated and non-treated cancer cells. To further understand the cytotoxicity of bleomycin and its relationship to GAGs, we used sodium chlorate to inhibit GAG sulfation and commercially available GAGs to compete for cell surface GAG/bleomycin interactions in seven cell lines including CHO745 defective in both heparan sulfate and chondroitin sulfate biosynthesis. we discovered that heparan sulfate GAG was significantly undersulfated and the quantity and disaccharide compositions of GAGs were changed in bleomycin-treated cells in a concentration- and time-dependent manner. We revealed that bleomycin-induced cytotoxicity was directly related to cell surface GAGs. GAGs were targeted by bleomycin both at cell surface and at Golgi. Thus, GAGs might be the biological relevant molecules that might be related to the bleomycin-induced fibrosis in certain cancer patients, a severe side effect with largely unknown molecular mechanism. © 2017 The Author(s). Published by S. Karger AG, Basel.

Polysulfonate suramin inhibits Zika virus infection.

PubMed

Tan, Chee Wah; Sam, I-Ching; Chong, Wei Lim; Lee, Vannajan Sanghiran; Chan, Yoke Fun

2017-07-01

Zika virus (ZIKV) is an arthropod-borne flavivirus that causes newborn microcephaly and Guillian-Barré syndrome in adults. No therapeutics are available to treat ZIKV infection or other flaviviruses. In this study, we explored the inhibitory effect of glycosaminoglycans and analogues against ZIKV infection. Highly sulfated heparin, dextran sulfate and suramin significantly inhibited ZIKV infection in Vero cells. De-sulfated heparin analogues lose inhibitory effect, implying that sulfonate groups are critical for viral inhibition. Suramin, an FDA-approved anti-parasitic drug, inhibits ZIKV infection with 3-5 log 10  PFU viral reduction with IC 50 value of ∼2.5-5 μg/ml (1.93 μM-3.85 μM). A time-of-drug-addition study revealed that suramin remains potent even when administrated at 1-24 hpi. Suramin inhibits ZIKV infection by preventing viral adsorption, entry and replication. Molecular dynamics simulation revealed stronger interaction of suramin with ZIKV NS3 helicase than with the envelope protein. Suramin warrants further investigation as a potential antiviral candidate for ZIKV infection. Heparan sulfate (HS) is a cellular attachment receptor for multiple flaviviruses. However, no direct ZIKV-heparin interaction was observed in heparin-binding analysis, and downregulate or removal of cellular HS with sodium chlorate or heparinase I/III did not inhibit ZIKV infection. This indicates that cell surface HS is not utilized by ZIKV as an attachment receptor. Copyright © 2017 Elsevier B.V. All rights reserved.

Control of fluid flow during Bridgman crystal growth using low-frequency vibrational stirring

NASA Astrophysics Data System (ADS)

Zawilski, Kevin Thomas

The goal of this research program was to develop an in depth understanding of a promising new method for stirring crystal growth melts called coupled vibrational stirring (CVS). CVS is a mixing technique that can be used in sealed systems and produces rapid mixing through vortex flows. Under normal operating conditions, CVS uses low-frequency vibrations to move the growth crucible along a circular path, producing a surface wave and convection in the melt. This research focused on the application of CVS to the vertical Bridgman technique. CVS generated flows were directly studied using a physical modeling system containing water/glycerin solutions. Sodium nitrate was chosen as a model growth system because the growth process could be directly observed using a transparent furnace. Lead magnesium niobate-lead titanate (PMNT) was chosen as the third system because of its potential application for high performance solid state transducers and actuators. In this study, the critical parameters for controlling CVS flows in cylindrical Bridgman systems were established. One of the most important results obtained was the dependence of an axial velocity gradient on the vibrational frequency. By changing the frequency, the intensity of fluid flow at a given depth can be easily manipulated. The intensity of CVS flows near the crystal-melt interface was found to be important. When flow intensity near the interface increased during growth, large growth rate fluctuations and significant changes in interface shape were observed. To eliminate such fluctuations, a constant flow rate near the crystal-melt interface was maintained by decreasing the vibrational frequency. A continuous frequency ramp was found to be essential to grow crystals of good quality under strong CVS flows. CVS generated flows were also useful in controlling the shape of the growth interface. In the sodium nitrate system without stirring, high growth rates produced a very concave interface. By adjusting the flow intensity near the interface, CVS flows were able to flatten the growth interface under these extreme growth conditions.

Synergistic Effects of Sodium Chloride, Glucose, and Temperature on Biofilm Formation by Listeria monocytogenes Serotype 1/2a and 4b Strains ▿ † ‡

PubMed Central

Pan, Youwen; Breidt, Frederick; Gorski, Lisa

2010-01-01

Biofilm formation by Listeria monocytogenes is generally associated with its persistence in the food-processing environment. Serotype 1/2a strains make up more than 50% of the total isolates recovered from food and the environment, while serotype 4b strains are most often associated with major outbreaks of human listeriosis. Using a microplate assay with crystal violet staining, we examined biofilm formation by 18 strains of each serotype in tryptic soy broth with varying concentrations of glucose (from 0.25% to 10.0%, wt/vol), sodium chloride (from 0.5% to 7.0%, wt/vol) and ethanol (from 1% to 5.0%, vol/vol), and at different temperatures (22.5°C, 30°C, and 37°C). A synergistic effect on biofilm formation was observed for glucose, sodium chloride, and temperature. The serotype 1/2a strains generally formed higher-density biofilms than the 4b strains under most conditions tested. Interestingly, most serotype 4b strains had a higher growth rate than the 1/2a strains, suggesting that the growth rate may not be directly related to the capacity for biofilm formation. Crystal violet was found to stain both bacterial cells and biofilm matrix material. The enhancement in biofilm formation by environmental factors was apparently due to the production of extracellular polymeric substances instead of the accumulation of viable biofilm cells. PMID:20048067

Crystallization of chicken egg white lysozyme from assorted sulfate salts

NASA Astrophysics Data System (ADS)

Forsythe, Elizabeth L.; Snell, Edward H.; Malone, Christine C.; Pusey, Marc L.

1999-01-01

Chicken egg white lysozyme has been found to crystallize from ammonium, sodium, potassium, rubidium, magnesium, and manganese sulfates at acidic and basic pH, with protein concentrations from 60 to 190 mg/ml. Crystals have also been grown at 4°C in the absence of any other added salts using isoionic lysozyme which was titrated to pH 4.6 with dilute sulfuric acid. Four different crystal forms have been obtained, depending upon the temperature, protein concentration, and precipitating salt employed. Crystals grown at 15°C were generally tetragonal, with space group P4 32 12. Crystallization at 20°C typically resulted in the formation of orthorhombic crystals, space group P2 12 12 1. The tetragonal ↔ orthorhombic transition appeared to be a function of both the temperature and protein concentration, occurring between 15 and 20°C and between 100 and 125 mg/ml protein concentration. Crystallization from 1.2 M magnesium sulfate at pH 7.8 gave a trigonal crystal, space group P3 12 1, a= b=87.4, c=73.7, γ=120°, which diffracted to 2.8 Å. Crystallization from ammonium sulfate at pH 4.6, generally at lower temperatures, was also found to result in a monoclinic form, space group C2, a=65.6, b=95.0, c=41.2, β=119.2°. A crystal of ˜0.2×0.2×0.5 mm grown from bulk solution diffracted to ˜3.5 Å.

The quaternary structure of the amidase from Geobacillus pallidus RAPc8 is revealed by its crystal packing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agarkar, Vinod B.; Kimani, Serah W.; Cowan, Donald A.

2006-12-01

The amidase from G. pallidus RAPc8, a moderate thermophile, converts amides to the corresponding acids and ammonia and has application as an industrial catalyst. RAPc8 amidase has been cloned, expressed and purified, and then crystallized using the hanging-drop vapour-diffusion method. The amidase from Geobacillus pallidus RAPc8, a moderate thermophile, is a member of the nitrilase enzyme superfamily. It converts amides to the corresponding acids and ammonia and has application as an industrial catalyst. RAPc8 amidase has been cloned and functionally expressed in Escherichia coli and has been purified by heat treatment and a number of chromatographic steps. The enzyme wasmore » crystallized using the hanging-drop vapour-diffusion method. Crystals produced in the presence of 1.2 M sodium citrate, 400 mM NaCl, 100 mM sodium acetate pH 5.6 were selected for X-ray diffraction studies. A data set having acceptable statistics to 1.96 Å resolution was collected under cryoconditions using an in-house X-ray source. The space group was determined to be primitive cubic P4{sub 2}32, with unit-cell parameter a = 130.49 (±0.05) Å. The structure was solved by molecular replacement using the backbone of the hypothetical protein PH0642 from Pyrococcus horikoshii (PDB code 1j31) with all non-identical side chains substituted with alanine as a probe. There is one subunit per asymmetric unit. The subunits are packed as trimers of dimers with D3 point-group symmetry around the threefold axis in such a way that the dimer interface seen in the homologues is preserved.« less

Disinfecting capabilities of oxychlorine compounds.

PubMed Central

Noss, C I; Olivieri, V P

1985-01-01

The bacterial virus f2 was inactivated by chlorine dioxide at acidic, neutral, and alkaline pH values. The rate of inactivation increased with increasing pH. Chlorine dioxide disproportionation products, chlorite and chlorate, were not active disinfectants. As chlorine dioxide solutions were degraded under alkaline conditions, they displayed reduced viricidal effectiveness, thereby confirming the chlorine dioxide free radical as the active disinfecting species. PMID:3911893

Widespread occurrence of (per)chlorate in the Solar System

NASA Astrophysics Data System (ADS)

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.

Widespread occurrence of (per)chlorate in the Solar System

USGS Publications Warehouse

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

2015-01-01

Perchlorate (ClO− 4 ) and chlorate (ClO− 3 ) are ubiquitous on Earth and ClO− 4 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 ClO− 4 and ClO− 3 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 ClO− 4 and ClO− 3 within some of the samples, and their relative abundance with respect to other soluble species (e.g., NO− 3 ) 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 ClO− 4 and ClO− 3 could be present throughout the Solar System.

Growth Temperature Dependence of Morphology of GaN Single Crystals in the Na-Li-Ca Flux Method

NASA Astrophysics Data System (ADS)

Wu, Xi; Hao, Hangfei; Li, Zhenrong; Fan, Shiji; Xu, Zhuo

2018-02-01

In this paper, the effect of growth temperature on the morphology and transparency of the GaN crystals obtained by the Li-Ca-added Na Flux method was studied. Addition of Li-Ca was attempted to control the growth habit and further improve transparency of GaN crystals. The samples with wurtzite structure of GaN were confirmed by the x-ray powder diffraction analysis. GaN single crystal with maximum size of about 6 mm was grown at 750°C. As the growth temperature was increased from 700°C to 850°C, the morphology of the crystals changed from pyramid to prism, and their surfaces became smooth. It was found that high growth temperature was beneficial to obtain a transparent crystal, but the evaporation of sodium would suppress its further growth. The E 2 (high) mode in the Raman spectra was at 568 cm-1, and the full-width at half-maximum values of this peak for the crystals obtained at 700°C, 750°C, 800°C, and 850°C were 7.5 cm-1, 10.3 cm-1, 4.4 cm-1, and 4.0 cm-1, respectively. It indicates that all the crystals are stress free and the transparent crystal grown at high temperature has high structural quality or low impurity concentrations.

Synthesis, crystal structure and optical properties of a novel sodium lead pentaborate, NaPbB{sub 5}O{sub 9}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Min; Graduate University of Chinese Academy of Sciences, Beijing 100049; Pan, Shilie, E-mail: slpan@ms.xjb.ac.c

A novel sodium lead pentaborate, NaPbB{sub 5}O{sub 9}, has been successfully synthesized by standard solid-state reaction. The single-crystal X-ray structural analysis showed that NaPbB{sub 5}O{sub 9} crystallizes in the monoclinic space group P2{sub 1}/c with a=6.5324(10) A, b=13.0234(2) A, c=8.5838(10) A, {beta}=104.971(10){sup o}, and Z=4. The crystal structure is composed of double ring [B{sub 5}O{sub 9}]{sup 3-} units, [PbO{sub 7}] and [NaO{sub 7}] polyhedra. [B{sub 5}O{sub 9}]{sup 3-} groups connect with each other forming two-dimensional infinite {sub {infinity}}[B{sub 5}O{sub 9}]{sup 3-} layers, while [PbO{sub 7}] and [NaO{sub 7}] polyhedra are located between the layers. [PbO{sub 7}] polyhedra linked together viamore » corner-sharing O atom forming novel infinite {sub {infinity}}[PbO{sub 6}] chains along the c axis. The thermal behavior, IR spectrum and the optical diffuse reflectance spectrum of NaPbB{sub 5}O{sub 9} were reported. -- Graphical abstract: A new phase, NaPbB{sub 5}O{sub 9}, has been discovered in the ternary M{sub 2}O-PbO-B{sub 2}O{sub 3} (M=alkali-metal) system. The crystal structure consists of a novel infinite {sub {infinity}}[PbO{sub 6}] chains. Display Omitted Research highlights: NaPbB{sub 5}O{sub 9} is the first borate discovered in the ternary M{sub 2}O-PbO-B{sub 2}O{sub 3} (M=alkali-metal) system. NaPbB{sub 5}O{sub 9} crystal structure includes a two-dimensional infinite {sub {infinity}}[B{sub 5}O{sub 9}]{sup 3-} layers and a novel one-dimensional infinite {sub {infinity}}[PbO{sub 6}] chains. [PbO{sub 7}] polyhedron has a highly asymmetric bonding configuration.« less

Physical property measurements of doped cesium iodide crystals

NASA Technical Reports Server (NTRS)

Synder, R. S.; Clotfelter, W. N.

1974-01-01

Mechanical and thermal property values are reported for crystalline cesium iodide doped with sodium and thallium. Young's modulus, bulk modulus, shear modulus, and Poisson's ratio were obtained from ultrasonic measurements. Young's modulus and the samples' elastic and plastic behavior were also measured under tension and compression. Thermal expansion and thermal conductivity were the temperature dependent measurements that were made.

Preparation and Characterization of Single Crystals and Epitaxial Layers of Silicon Carbide by Molten Salt Electrolysis.

DTIC Science & Technology

1980-10-01

requires the simultaneous cathodic deposi- tion of silicon and carbon under conditions where reaction to form SiC will occur. In this study sodium or...reactivity with the melt. Nickel suffers from the disadvantage that it reacts with silicon to form nickel silicides , but the concentration of silicides in

Overexpression, crystallization and preliminary X-ray crystallographic analysis of erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa.

PubMed

Ha, Jun Yong; Lee, Ji Hyun; Kim, Kyoung Hoon; Kim, Do Jin; Lee, Hyung Ho; Kim, Hye-Kyung; Yoon, Hye-Jin; Suh, Se Won

2006-02-01

The enzyme erythronate-4-phosphate dehydrogenase catalyses the conversion of erythronate-4-phosphate to 3-hydroxy-4-phospho-hydroxy-alpha-ketobutyrate. It belongs to the D-isomer-specific 2-hydroxyacid dehydrogenase family. It is essential for de novo biosynthesis of vitamin B6 (pyridoxine). Erythronate-4-phosphate dehydrogenase from Pseudomonas aeruginosa, a homodimeric enzyme consisting of two identical 380-residue subunits, has been overexpressed in Escherichia coli with a C-terminal purification tag and crystallized at 297 K using 0.7 M ammonium dihydrogen phosphate, 0.4 M ammonium tartrate, 0.1 M sodium citrate pH 5.6 and 10 mM cupric chloride. X-ray diffraction data were collected to 2.20 A from a crystal grown in the presence of NADH. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 84.77, b = 101.28, c = 142.58 A. A dimeric molecule is present in the asymmetric unit, giving a crystal volume per protein weight (VM) of 3.64 A3 Da(-1) and a solvent content of 66%.

Salt or cocrystal of salt? Probing the nature of multicomponent crystal forms with infrared spectroscopy

NASA Astrophysics Data System (ADS)

da Silva, Cameron Capeletti; Guimarães, Freddy Fernandes; Ribeiro, Leandro; Martins, Felipe Terra

2016-10-01

The recognition of the nature of a multicomponent crystal form (solvate, salt, cocrystal or cocrystal of salt) is of great importance for pharmaceutical industry because it is directly related to the performance of a pharmaceutical ingredient, since there is interdependence between the structure, its energy and its physical properties. In this context, here we have identified the nature of multicomponent crystal forms of the anti-HIV drug lamivudine with mandelic acid through infrared spectroscopy. These investigated crystal forms were the known S-mandelic acid cocrystal of lamivudine R-mandelate trihydrate (1), a cocrystal of salt, and lamivudine R-mandelate (2), a salt. This approach also supports the identification and distinction of both ionized and unionized forms of mandelic acid in the infrared spectrum of 1. In this way, infrared spectroscopy can be useful to distinguish a cocrystal of salt from either salt or cocrystal forms. In the course of this study, for the first time we have also characterized and determined the crystal structure of R-mandelic acid cocrystal of sodium R-mandelate (3).

Multilayer Films and Capsules of Sodium Carboxymethylcellulose and Polyhexamethylenguanidine Hydrochloride

NASA Astrophysics Data System (ADS)

Guzenko, Nataliia; Gabchak, Oleksandra; Pakhlov, Evgenij

The complexation of polyhexamethylenguanidine hydrochloride (PHMG) and sodium carboxymethylcellulose (CMC) was investigated for different conditions. Mixing of equiconcentrated aqueous solutions of the polyelectrolytes was found to result in the formation of an insoluble interpolyelectrolyte complex with an overweight of carboxymethylcellulose. A step-by-step formation of stable, irreversibly adsorbed multilayer film of the polymers was demonstrated using the quartz crystal microbalance method. Unusually thick polymer shells with a large number of loops and tails of the polyanion were formed by the method of layer-by-layer self-assembly of PHMG and CMC on spherical CaCO3 particles. Hollow multilayer capsules stable in neutral media were obtained by dissolution of the inorganic matrix in EDTA solution.

Dissolution and mechanical behaviors of recrystallized carbamazepine from alcohol solution in the presence of additives

NASA Astrophysics Data System (ADS)

Nokhodchi, A.; Bolourtchian, N.; Dinarvand, R.

2005-02-01

Carbamazepine (CBZ) crystals were grown from pure ethanol solutions containing various additives (PEG 4000, PVP K30 or Tween 80). Physical characteristics of the crystals were studied for the morphology of crystals using scanning electron microscope, for the identification of polymorphism by X-ray powder diffraction (XRPD) and FT-IR, and for thermodynamic properties using differential scanning calorimetery (DSC). The dissolution behaviour of various carbamazepine crystals was also studied by dissolution apparatus II at pH 7.4 containing 1% sodium lauryl sulphate (SLS). The scanning electron micrograph (SEM) studies showed that the presence of the additives in the solutions growth medium affected the morphology and size of carbamazepine crystals. SEMs of untreated and treated carbamazepine crystals obtained from alcohol containing PEG 4000, PVP K30 or Tween 80 showed that the crystal shape of untreated carbamazepine is flaky or thin plate-like, whereas the crystals obtained from alcohol containing no additive, PEG 4000, PVP K30 or Tween 80 are polyhedral prismatic, block-shaped, polyhedral or hexagonal, respectively. XRPD, FT-IR and DSC results showed that the untreated CBZ was form III and recrystallization of CBZ in the absence or presence of the additives did not cause any polymorphic changes. The results showed that the higher dissolution rate and compact strength were observed for the crystals obtained in the presence of PVP K30. The presence of the additives in crystallization medium alters crystal morphology of carbamazepine, but only the samples crystallized in the presence of PVP K30 showed an improvement in dissolution rate and tensile strength.

Crystallization and preliminary X-ray diffraction analysis of the periplasmic domain of the Escherichia coli aspartate receptor Tar and its complex with aspartate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mise, Takeshi; Matsunami, Hideyuki; Samatey, Fadel A.

The periplasmic domain of the E. coli aspartate receptor Tar was cloned, expressed, purified and crystallized with and without bound ligand. The crystals obtained diffracted to resolutions of 1.58 and 1.95 Å, respectively. The cell-surface receptor Tar mediates bacterial chemotaxis toward an attractant, aspartate (Asp), and away from a repellent, Ni{sup 2+}. To understand the molecular mechanisms underlying the induction of Tar activity by its ligands, the Escherichia coli Tar periplasmic domain with and without bound aspartate (Asp-Tar and apo-Tar, respectively) were each crystallized in two different forms. Using ammonium sulfate as a precipitant, crystals of apo-Tar1 and Asp-Tar1 weremore » grown and diffracted to resolutions of 2.10 and 2.40 Å, respectively. Alternatively, using sodium chloride as a precipitant, crystals of apo-Tar2 and Asp-Tar2 were grown and diffracted to resolutions of 1.95 and 1.58 Å, respectively. Crystals of apo-Tar1 and Asp-Tar1 adopted space group P4{sub 1}2{sub 1}2, while those of apo-Tar2 and Asp-Tar2 adopted space groups P2{sub 1}2{sub 1}2{sub 1} and C2, respectively.« less

Crystallization and preliminary X-ray diffraction studies of polyketide synthase-1 (PKS-1) from Cannabis sativa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taguchi, Chiho; Quantum Beam Science Directorate, Japan Atomic Energy Agency; Taura, Futoshi

Polyketide synthase-1 from C. sativa has been crystallized. The crystal diffracted to 1.55 Å resolution with sufficient quality for further structure determination. Polyketide synthase-1 (PKS-1) is a novel type III polyketide synthase that catalyzes the biosynthesis of hexanoyl triacetic acid lactone in Cannabis sativa (Mexican strain). PKS-1 was overproduced in Escherichia coli, purified and finally crystallized in two different space groups. The crystal obtained in 0.1 M HEPES buffer pH 7.5 containing 0.2 M calcium acetate and 20%(w/v) polyethylene glycol 3350 diffracted to 1.65 Å resolution and belonged to space group P1, with unit-cell parameters a = 54.3, b =more » 59.3, c = 62.6 Å, α = 69, β = 81, γ = 80°. Another crystal obtained in 0.1 M HEPES buffer pH 7.5 containing 0.2 M sodium chloride and 20%(w/v) polyethylene glycol 3350 diffracted to 1.55 Å resolution and belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 54.3, b = 110, c = 130 Å. These data will enable us to determine the crystal structure of PKS-1.« less

Influence of sodium fluoride (NaF) on the crystallization and spectral properties of L-tyrosine

NASA Astrophysics Data System (ADS)

Thenmozhi, M.; Suguna, K.; Sekar, C.

2011-12-01

L-Tyrosine (C 9H 11NO 3) is an essential amino acid in living organisms. It is also a building unit in protein, takes part in bio-synthesis of hormones, neurotransmitters, pigments and one of the organic chemical constituents of urinary stones. L-Tyrosine has been crystallized in silica gel by double diffusion technique with and without the addition of NaF. The crystals had rosette-like shape. In case of fluoride addition, two types of crystals have formed: rosette like crystallites, at the gel-solution interface and reticulate type crystallites beneath the interface. XRD results confirmed that both the products are of L-tyrosine with identical crystal structures. Crystal structure, morphology, thermal and spectral properties are analyzed using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR) and UV-vis transmittance studies. The TG-DTA results suggest that the thermal stability of L-tyrosine has markedly improved due to fluoride doping. Optical band gap energy of NaF grown L-tyrosine crystallite is estimated as 4.28 eV. Second harmonic generation efficiency test indicates that L-tyrosine crystals can be used for application in nonlinear optical devices.

Crystallization and X-ray diffraction analysis of an l-arabinonate dehydratase from Rhizobium leguminosarum bv. trifolii and a d-xylonate dehydratase from Caulobacter crescentus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, Mohammad Mubinur; Andberg, Martina; Koivula, Anu

l-Arabinonate dehydratase and d-xylonate dehydratase from the IlvD/EDD family were crystallized by the vapour-diffusion method. Diffraction data sets were collected to resolutions of 2.40 and 2.66 Å from crystals of l-arabinonate dehydratase and d-xylonate dehydratase, respectively. l-Arabinonate dehydratase (EC 4.2.1.25) and d-xylonate dehydratase (EC 4.2.1.82) are two enzymes that are involved in a nonphosphorylative oxidation pathway of pentose sugars. l-Arabinonate dehydratase converts l-arabinonate into 2-dehydro-3-deoxy-l-arabinonate, and d-xylonate dehydratase catalyzes the dehydration of d-xylonate to 2-dehydro-3-deoxy-d-xylonate. l-Arabinonate and d-xylonate dehydratases belong to the IlvD/EDD family, together with 6-phosphogluconate dehydratases and dihydroxyacid dehydratases. No crystal structure of any l-arabinonate or d-xylonate dehydratasemore » is available in the PDB. In this study, recombinant l-arabinonate dehydratase from Rhizobium leguminosarum bv. trifolii (RlArDHT) and d-xylonate dehydratase from Caulobacter crescentus (CcXyDHT) were heterologously expressed in Escherichia coli and purified by the use of affinity chromatography followed by gel-filtration chromatography. The purified proteins were crystallized using the hanging-drop vapour-diffusion method at 293 K. Crystals of RlArDHT that diffracted to 2.40 Å resolution were obtained using sodium formate as a precipitating agent. They belonged to space group P2{sub 1}, with unit-cell parameters a = 106.07, b = 208.61, c = 147.09 Å, β = 90.43°. Eight RlArDHT molecules (two tetramers) in the asymmetric unit give a V{sub M} value of 3.2 Å{sup 3} Da{sup −1} and a solvent content of 62%. Crystals of CcXyDHT that diffracted to 2.66 Å resolution were obtained using sodium formate and polyethylene glycol 3350. They belonged to space group C2, with unit-cell parameters a = 270.42, b = 236.13, c = 65.17 Å, β = 97.38°. Four CcXyDHT molecules (a tetramer) in the asymmetric unit give a V{sub M} value of 4.0 Å{sup 3} Da{sup −1} and a solvent content of 69%.« less

Radiation-Induced Damage to Nucleic Acid Constituents

NASA Astrophysics Data System (ADS)

Kim, Heasook

The objective of this research was to identify the primary free radical species produced by ionizing radiation in DNA. The ultimate goal would be to use these data obtained from model compounds to analyze radiation-induced damage in DNA itself. The different single crystals were studied in detail. The first was the sodium salt of guanosine-3 ^':5^' -cyclic monophosphate (cyclic GMP). The results of studies on crystals irradiated at 4.2^ circK distinguished two species. One of these species exhibited a non-exchangeable proton coupling that was characterized by ENDOR spectroscopy and shown to be sigma proton. The spin density on C8 was deduced from the ENDOR hyperfine coupling tensor and found to be 0.15. The second species also exhibited a non-exchangeable sigma proton coupling and a beta proton coupling. The spin densities on C8 and N9 were deduced from ENDOR measurements to be 0.09 and 0.36. The former is attributed to the oxidation product and the latter to the primary reduction product. These products are respectively the guanine cation and anion. The second single crystal studied was a sodium salt of 2^'-deoxyguanosine -5^'-monophosphate tetrahydrate. The ESR and ENDOR spectra obtained from this crystal after x-irradiation at 4.2^circK were complex and the paramagnetic species were tentatively identified as ionic species. The third DNA model compound studied was thymidine. Single crystal of thymidine were irradiated at 1.6^ circK and at 4.2^circ K. The lower temperature preserved a more primitive stage of the radiation damage process. ENDOR measurements distinguished three paramagnetic species. The most interesting component of the paramagnetic absorption in crystals irradiated at 1.6^circK is attributed to trapped electron. These electrons are stabilized by the electrostatic fields generated by hydroxy dipoles. The hyperfine couplings between the trapped electron and the proton of these polar groups were deduced from ENDOR measurements. The ESR and ENDOR measurements described in this report were carried out DNA model compounds x-irradiated and measured at lower temperatures than reported previously. The experiments have demonstrated that an earlier stage of radiation damage can sometimes be stabilized and characterized in single crystals by maintaining the sample at 1.4 ^circK. (Abstract shortened with permission of author.).

A protein coated piezoelectric crystal detector

NASA Astrophysics Data System (ADS)

Suleiman, Ahmad; Pender, Marie; Ngeh-Ngwainbi, Jerome; Lubrano, Glenn; Guilbault, George

1990-05-01

The purpose of this project was to develop a protein coated, portable piezoelectric crystal detector for organophosphorus compounds. The performance of acetylcholinesterase, GD-1 anti-soman, anti-DMMP antibody, and bovine serum albumin (BSA) coatings was evaluated. Different immobilization methods were also tested. The responses obtained with the protein coatings immobilized via cross-linking with glutaraldehyde were acceptable, provided that the reference crystal was coated with dextran. The proposed coatings showed good stability and reasonable lifetimes that ranged from approximately three weeks in the case of the antibody coatings to several months in the case of BSA. Although moisture, gasoline, and sulfur are potential interferents, their effects on the sensor were eliminated by using a sodium sulfate scrubber which did not affect the performance of the detector towards organophosphates. A small, battery operated portable instrument capable of real time measurements with alarm function was produced. The instrument can be used in a wide range of applications, depending on the coatings applied to the crystals.

Expression, purification, crystallization and preliminary X-ray characterization of a putative glycosyltransferase of the GT-A fold found in mycobacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fulton, Zara; Crellin, Paul K.; Brammananth, Rajini

2008-05-28

Glycosidic bond formation is a ubiquitous enzyme-catalysed reaction. This glycosyltransferase-mediated process is responsible for the biosynthesis of innumerable oligosaccharides and glycoconjugates and is often organism- or cell-specific. However, despite the abundance of genomic information on glycosyltransferases (GTs), there is a lack of structural data for this versatile class of enzymes. Here, the cloning, expression, purification and crystallization of an essential 329-amino-acid (34.8 kDa) putative GT of the classic GT-A fold implicated in mycobacterial cell-wall biosynthesis are reported. Crystals of MAP2569c from Mycobacterium avium subsp. paratuberculosis were grown in 1.6 M monoammonium dihydrogen phosphate and 0.1 M sodium citrate pH 5.5.more » A complete data set was collected to 1.8 {angstrom} resolution using synchrotron radiation from a crystal belonging to space group P4{sub 1}2{sub 1}2.« less

Purification, crystallization, small-angle X-ray scattering and preliminary X-ray diffraction analysis of the SH2 domain of the Csk-homologous kinase.

PubMed

Gunn, Natalie J; Gorman, Michael A; Dobson, Renwick C J; Parker, Michael W; Mulhern, Terrence D

2011-03-01

The C-terminal Src kinase (Csk) and Csk-homologous kinase (CHK) are endogenous inhibitors of the proto-oncogenic Src family of protein tyrosine kinases (SFKs). Phosphotyrosyl peptide binding to their Src-homology 2 (SH2) domains activates Csk and CHK, enhancing their ability to suppress SFK signalling; however, the detailed mechanistic basis of this activation event is unclear. The CHK SH2 was expressed in Escherichia coli and the purified protein was characterized as monomeric by synchrotron small-angle X-ray scattering in-line with size-exclusion chromatography. The CHK SH2 crystallized in 0.2 M sodium bromide, 0.1 M bis-Tris propane pH 6.5 and 20% polyethylene glycol 3350 and the best crystals diffracted to ∼1.6 Å resolution. The crystals belonged to space group P2, with unit-cell parameters a=25.8, b=34.6, c=63.2 Å, β=99.4°.

Purification, crystallization and preliminary X-ray diffraction analysis of GatD, a glutamine amidotransferase-like protein from Staphylococcus aureus peptidoglycan

PubMed Central

Vieira, Diana; Figueiredo, Teresa A.; Verma, Anil; Sobral, Rita G.; Ludovice, Ana M.; de Lencastre, Hermínia; Trincao, Jose

2014-01-01

Amidation of peptidoglycan is an essential feature in Staphylococcus aureus that is necessary for resistance to β-lactams and lysozyme. GatD, a 27 kDa type I glutamine amidotransferase-like protein, together with MurT ligase, catalyses the amidation reaction of the glutamic acid residues of the peptidoglycan of S. aureus. The native and the selenomethionine-derivative proteins were crystallized using the sitting-drop vapour-diffusion method with polyethylene glycol, sodium acetate and calcium acetate. The crystals obtained diffracted beyond 1.85 and 2.25 Å, respectively, and belonged to space group P212121. X-ray diffraction data sets were collected at Diamond Light Source (on beamlines I02 and I04) and were used to obtain initial phases. PMID:24817726

Ultrasonic Resonance Spectrometry with Fourier Synthesized Pseudorandom Noise Excitation and Its Application to a Lyotropiec Liquid Crystal

NASA Astrophysics Data System (ADS)

Nakamura, Haruki; Naito, Yasushi; Tsuboi, Yukitoshi; Mitaku, Shigeki; Okano, Koji

1982-11-01

Time domain measurement to obtain ultrasonic resonance spectra was made using Fourier Synthesized Pseudorandom Noise (FSPN) excitation in order to observe the viscoelastic property of a lyotropic liquid crystal. The FSPN with multiple frequency components was amplitude-modulated by a carrier signal with a much higher single frequency component, and a quadrature detection technique was used to obtain a shear ultrasonic resonance spectrum produced between two transducers. A reflection method was applied to observe mechanical impedance of viscous and elastic materials at about 3 MHz. The viscosities obtained for standard viscous materials agreed well with literature values, and the rigidity and viscosity of a lyotropic liquid crystal of Sodium Lauryl Sulfate with water were measured; they were ˜ 106 dyn/cm2 and ˜0.1 P, respectively.

Crystallization and Preliminary X-ray Diffraction Analysis of Hemextin A: A Unique Anticoagulant Protein from Hemachatus haemachatus Venom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee,Y.; Kumar, S.; Jobichen, C.

2007-01-01

Hemextin A was isolated and purified from African Ringhals cobra (Hemachatus haemachatus). It is a three-finger toxin that specifically inhibits blood coagulation factor VIIa and clot formation and that also interacts with hemextin B to form a unique anticoagulant complex. Hemextin A was crystallized by the hanging-drop vapor-diffusion method by equilibration against 0.2 M ammonium acetate, 0.1 M sodium acetate trihydrate pH 4.6 and 30% PEG 4000 as the precipitating agent. The crystals belong to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 49.27, b = 49.51, c = 57.87 {angstrom} and two molecules in the asymmetricmore » unit. They diffracted to 1.5 {angstrom} resolution at beamline X25 at BNL.« less

Treatment of textile wastewaters using Eutectic Freeze Crystallization.

PubMed

Randall, D G; Zinn, C; Lewis, A E

2014-01-01

A water treatment process needs to recover both water and other useful products if the process is to be viewed as being financially and environmentally sustainable. Eutectic Freeze Crystallization (EFC) is one such sustainable water treatment process that is able to produce both pure ice (water) and pure salt(s) by operating at a specific temperature. The use of EFC for the treatment of water is particularly useful in the textile industry because ice crystallization excludes all impurities from the recovered water, including dyes. Also, EFC can produce various salts with the intention of reusing these salts in the process. This study investigated the feasibility of EFC as a treatment method for textile industry wastewaters. The results showed that EFC can be used to convert 95% of the wastewater stream to pure ice (98% purity) and sodium sulfate.

Gastric air contrast: useful adjunct to hepatic artery scintigraphy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wahl, R.L.; Ziessman, H.A.; Juni, J.

The utility of scintigraphic views obtained after administration of sodium bicarbonate-citric acid-simethicone crystals (E-Z-GAS) for the determination of gastric extrahepatic perfusion was evaluated in 20 technetium-99m macroaggregated albumin hepatic arterial perfusion studies performed in 19 patients. These crystals produce carbon dioxide gas, distend the stomach, and allow better delineation of gastric activity (extrahepatic perfusion to the stomach). Conversely, a lack of change in activity in the left upper quadrant after the effervescent crystals have been ingested suggests no gastric activity (and no extrahepatic perfusion to the stomach). These air-contrast views added useful information in 16 of 20 studies. Air contrastmore » views of the stomach can be extremely helpful in verifying or excluding the diagnosis of gastric extrahepatic perfusion on technetium-99m macroaggregated albumin hepatic arterial perfusion studies.« less

Hydrogeology, degradation of ground-water quality, and simulation of infiltration from the Delaware River into the Potomac aquifers, northern Delaware

USGS Publications Warehouse

Phillips, S.W.

1987-01-01

Brackish water is infiltrating from the Delaware River into the underlying Potomac aquifers in the Cretaceous Potomac Formation in northern Delaware. Evidence that infiltration at the river is actually occurring includes chloride concentrations in the aquifers that are above ambient levels and chemical characteristics of groundwater and river water that are similar. Water quality within the Potomac aquifers has been degraded by the infiltration of river water and by leachate from waste disposal sites. The ambient groundwater has chloride concentrations from 10 to 21 mg/L. Chemical analyses indicate that the ambient groundwater is a sodium magnesium calcium-chloride sulfate bicarbonate type. Areas of the Potomac aquifers that have been degraded have chloride concentrations from 40 to 8,600 m/L, with specific conductances of 200 to 27 ,200 microsiemens/cm at 25 C. Chemical analyses indicate the groundwater in these areas is a sodium-chlorate type. Two wells in the lower Potomac aquifer near the Wilmington Marine Terminal also have been affected by the infiltration of river water. Leachate from waste disposal sites has caused localized groundwater degradation in all three Potomac aquifers, especially north of the Delaware Memorial Bridge and at sites near Army Creek and Red Lion Creek. Chloride concentrations up to 8,600 mg/L have resulted from waste disposal leachate. Simulated infiltration of river water into the Potomac aquifers accounts for approximately 6 to 12% of the total aquifer recharge in the area of influence of the pumping. There is a direct correlation between the rate of infiltration of river water and the total well-field pumpage. The rate of infiltration of river water for the pumping scenarios ranged from 0.31 to 0.62 million gal/day. Simulations of freshwater injection demonstrated that 12 barriers wells, each injecting 300 gal/min, would be needed to create a barrier against the infiltration of river water in the upper Potomac aquifer, whereas the middle Potomac aquifer would require 7 wells in injecting 200 gal/min. (Author 's abstract)

The tropical fruit and nut collections and research activities at the USDA-ARS Pacific Basin Agricultural Research Center, Tropical Plant Genetic Resource and Disease Research unit

USDA-ARS?s Scientific Manuscript database

In Hawaii, consistency and reliability are important factors determining the success of a crop, for example, longan generated the highest income return for the farmers among the Sapindaceae (lychee, longan and rambutan) group in 2006 because of the use of potassium chlorate for off-season production...

Development of Standard Testing Method for Water Taste Effects.

DTIC Science & Technology

potassium chlorogenate , as well as another chemical, potassium chlorate, were tested on thirty eight subjects. In about one third of the subjects...increasing the concentration of the potassium chlorogenate used as the adapting solution resulted in sweet water tastes of increasing intensity. Some...subjects perceived water after potassium chlorogenate as sweet but the sweetness did not increase substantially as the concentration of potassium

Portable Home Welder

NASA Technical Reports Server (NTRS)

1976-01-01

Pyronetics, Inc. manufactured a small, do-it-yourself welding torch which weighs only 7 pounds, gives a 5,000 degree Farenheit flame, and costs only $40.00. This resulted from information provided by a NASA Industrial Application Center at the University of Southern California. The center provided information on chlorate candles, unique in that they generate oxygen while burning. A retrospective search uncovered information on composition, hazards, applications, manufacturers, and shipping regulations.

Enhanced chlorine dioxide decay in the presence of metal oxides: relevance to drinking water distribution systems.

PubMed

Liu, Chao; von Gunten, Urs; Croué, Jean-Philippe

2013-08-06

Chlorine dioxide (ClO2) decay in the presence of typical metal oxides occurring in distribution systems was investigated. Metal oxides generally enhanced ClO2 decay in a second-order process via three pathways: (1) catalytic disproportionation with equimolar formation of chlorite and chlorate, (2) reaction to chlorite and oxygen, and (3) oxidation of a metal in a reduced form (e.g., cuprous oxide) to a higher oxidation state. Cupric oxide (CuO) and nickel oxide (NiO) showed significantly stronger abilities than goethite (α-FeOOH) to catalyze the ClO2 disproportionation (pathway 1), which predominated at higher initial ClO2 concentrations (56-81 μM). At lower initial ClO2 concentrations (13-31 μM), pathway 2 also contributed. The CuO-enhanced ClO2 decay is a base-assisted reaction with a third-order rate constant of 1.5 × 10(6) M(-2) s(-1) in the presence of 0.1 g L(-1) CuO at 21 ± 1 °C, which is 4-5 orders of magnitude higher than in the absence of CuO. The presence of natural organic matter (NOM) significantly enhanced the formation of chlorite and decreased the ClO2 disproportionation in the CuO-ClO2 system, probably because of a higher reactivity of CuO-activated ClO2 with NOM. Furthermore, a kinetic model was developed to simulate CuO-enhanced ClO2 decay at various pH values. Model simulations that agree well with the experimental data include a pre-equilibrium step with the rapid formation of a complex, namely, CuO-activated Cl2O4. The reaction of this complex with OH(-) is the rate-limiting and pH-dependent step for the overall reaction, producing chlorite and an intermediate that further forms chlorate and oxygen in parallel. These novel findings suggest that the possible ClO2 loss and the formation of chlorite/chlorate should be carefully considered in drinking water distribution systems containing copper pipes.

Evaluation of Salmonella enteritidis in molting hens after administration of an experimental chlorate product (for nine days) in the drinking water and feeding an alfalfa molt diet.

PubMed

McReynolds, J; Kubena, L; Byrd, J; Anderson, R; Ricke, S; Nisbet, D

2005-08-01

The method most commonly used to induce molting and stimulate multiple egg-laying cycles in laying hens for commercial egg production is to fast the hens. Unfortunately, increased risk of Salmonella enteritidis (SE) infection may result from the use of this method. Methods to stimulate multiple egg-laying cycles without increasing the risk of SE infection are needed. Hens over 50 wk of age were divided into 12 groups of 11 hens each and placed in individual laying cages. One week prior to dietary changes, hens were placed on an 8-h light and 16-h dark photoperiod that continued for the 9-d molt. All hens were challenged orally with 10(6) cfu of SE on the fourth day of the molt. Treatments were nonfed hens with distilled water (NFD), nonfed hens with the experimental chlorate product (ECP, which provided 15 mM chlorate ion) water (NFECP), alfalfa diets with distilled water (ALD), and alfalfa diets with ECP water (ALECP). In the NFD hens, 67% (log10 2.74) of the crops and 94% (log10 5.62) of the ceca were colonized, whereas for the NFECP hens significant reductions to 22% (log10 1.05) of the crops and 61% (log10 2.44) of the ceca were observed. In the ALD hens, 61% (log10 2.52) of the crops and 94% (log10 4.06) of the ceca were colonized. In the ALECP hens, highly significant reductions to 11% (log10 1.26) of the crops and 39% (log10 1.12) of the ceca were observed. When compared with the NFD hens, significant reductions in SE invasion of the ovary, liver, and spleen occurred in all other treatments, except the ovary in the ALD hens. The low alfalfa intake is probably a factor in our lowered protection against SE when compared with previous results. For several parameters, these results suggest that ECP or the combination of ECP and alfalfa may be a useful tool to reduce the risk of SE during an induced molt.