Sample records for chromium bromides

  1. Electrodeposition of Nanocrystalline Chromium Coatings Based on 1-Butyl-3-Methylimidazolium-Bromide Ionic Liquid.

    He, Xinkuai; Zhu, Qingyun; Hou, Bailong; Cai, Youxing; Li, Chen; Fu, Liqin; Wu, Luye


    The electrochemical behavior of trivalent chromium reduction from 1-butyl-3-methylimidazolium-bromide ([BMIM]Br) ionic liquid is studied. The result of cyclic voltammetry shows that the Cr(III) reduction is irreversible and occurs in two steps, Cr(III)to Cr(II), and Cr(II) to Cr(0), respectively. In the electrochemical impedance spectroscopy measurements, the preferable equivalent circuit is made to fit the experimental data. The effects of electroplating parameters on coating thickness and electrodepositon rate are investigated by potentiostatic method on Cu electrode from Cr(III)-[BMIM]Br solution. The results show that the temperature and depositing potential have great effect on the coating thickness and electrodeposition rate. The surface morphology and composition of deposited Cr are investigated using scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS). SEM analysis shows that chromium electrodeposits obtained on Cu electrodes present a ball-like structure. EDS analysis shows that the coatings are composed of Cr. Moreover, the corrosion resistance of the as-deposited chromium layer is evaluated using polarization curves. The results show that the corrosion resistance of the chromium coatings obtained at higher potential is better. PMID:26682363

  2. Adsorption of hexavalent chromium onto montmorillonite modified with hydroxyaluminum and cetyltrimethylammonium bromide

    Aluminum hydroxypolycation and cetyltrimethylammonium bromide (CTMAB) were chosen to synthesize inorganic-organic pillared montmorillonite. Three different methods were employed for the intercalation. The characteristics of natural and modified montmorillonite were determined with X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectrum (XPS), and zeta potential. It was found that aluminum hydroxypolycation and CTMAB had either entered the interlayer or sorbed on the external surface of the clay. Different intercalation orders can result in different structures. Batch adsorption of hexavalent chromium (Cr6+) onto modified montmorillonite was also investigated. The experimental data revealed that if aluminum hydroxypolycation was intercalated before CTMAB, the adsorption capacity was better than that of intercalated simultaneously or CTMAB pre-intercalated. The pH of the solution and environmental temperature had significant influences on the adsorption of Cr6+. The optimal pH for the removal was about 4, and the temperature of 298 K was best suitable. All adsorption processes were rapid during the first 5 min and reached equilibrium in 20 min. The adsorption kinetics can be described quite well by pseudo-second-order model. The adsorption rates of ACM, CAM and ACCOM were 3.814, 0.915, and 3.143 mg/g/min, respectively. The adsorption capacities of Cr6+ at 298 K on ACM, CAM, and ACCOM inferred from the Langmuir model were 11.970, 6.541, and 9.090 mg/g, respectively. The adsorption of Cr6+ on modified montmorillonite was mainly induced by the surface charge and the complexation reaction between CTMA+ and hexavalent chromium species at the edge of the clay particle.

  3. Removal of hexavalent chromium by using red mud activated with cetyltrimethylammonium bromide.

    Li, Deliang; Ding, Ying; Li, Lingling; Chang, Zhixian; Rao, Zhengyong; Lu, Ling


    The removal of hexavalent chromium [Cr(VI)] from aqueous solution by using red mud activated with cetyltrimethylammonium bromide (CTAB) was studied. The optimum operation parameters, such as CTAB concentration, pH values, contact time, and initial Cr(VI) concentration, were investigated. The best concentration of CTAB for modifying red mud was found to be 0.50% (mCTAB/VHCl,0.6 mol/L). The lower pH (removal of Cr(VI). Red mud activated with CTAB can greatly improve the removal ratio of Cr(VI) as high as four times than that of original red mud. Adsorption equilibrium was reached within 30 min under the initial Cr(VI) concentration of 100 mg L(-1). The isotherm data were analysed using Langmuir and Freundlich models. The adsorption of Cr(VI) on activated red mud fitted well to the Langmuir isotherm model, and the maximum adsorption capacity was estimated as 22.20 mg g(-1) (Cr/red mud). The adsorption process could be well described using the pseudo-second-order model. The result shows that activated red mud is a promising agent for low-cost water treatment. PMID:25299348

  4. Chromium

    ... health risks of too much chromium? Chromium and medication interactions Supplemental sources of chromium Chromium and Healthful Diets References Disclaimer What foods provide chromium? Chromium is widely distributed in the ...

  5. Removal of Hexavalent Chromium from Aqueous Solutions Using Magnetic Nanoparticles Coated with Alumina and Modified by Cetyl Trimethyl Ammonium Bromide

    Mohammad Malakootian


    Full Text Available Introduction: The development of an effective method regarding chromium removal from the environment is of great importance. Therefore, the present study aimed to examiner magnetic nanoparticles coated with alumina modified by Cetyl Trimethyl Ammonium Bromide (CTAB in the removal of Cr6+ through magnetic solid phase extraction method. Materials & Methods: At first, iron oxide nanoparticles were synthesized, coated with alumina, modified with CTAB and characterized with suitable instruments. The factors affecting the process of chromium removal were investigated, including the concentration of CTAB, the pH, the amount of nanoparticles, the sample volume, a proper eluent, the adsorption and desorption time, and the effect of interfering ions. Moreover, the chromium concentration was determined by flame atomic absorption spectrometric (FAAS technique. The adsorption isotherm, adsorption capacity, and recoverability of the adsorbent were further examined. Results: The modified magnetic nanoparticles were demonstrated to be homogeneous, spherical, with a size lower than 20 nanometer having a magnetic property. The optimal conditions for chromium removal entailed 7*10-6 mol/L concentration of CTAB, pH range of 6-8, 0.1 g of the nanoparticles, 10 mL volume of the chromium sample (5 μg mL-1, nitric acid 2 M as a suitable eluent, 15 minutes of adsorption and desorption, and no interference of interfering ions in the process of chromium separation. The process efficiency under optimal conditions was determined to be over 95%, which this process followed the Langmuir adsorption isotherm. The adsorption capacity proved to be 23.8 mg/g. Reusing after four times of adsorbent recovering was effective in the chromium removal (80%. The method accuracy for five measurement times was 4.155% and the method’s LOD was 0.081 mg/L. Conclusion: The method enjoys the benefits of convenient preparation of the adsorbent, high selectivity, high accuracy, short process

  6. Effect of gemini (alkanediyl-α,ω-bis(dimethylcetylammonium bromide)) (16-s-16, s=4, 5, 6) surfactants on the interaction of ninhydrin with chromium-glycylphenylalanine.

    Kumar, Dileep; Rub, Malik Abdul; Akram, Mohd; Kabir-ud-Din


    The effect of gemini (alkanediyl-α,ω-bis(dimethylcetylammonium bromide)) (16-s-16, s=4, 5, 6) surfactants on the interaction of ninhydrin with chromium(III) complex of glycylphenylalanine ([Cr(III)-Gly-Phe]2+) has been investigated using UV-visible spectrophotometer at different temperatures. The order of reaction with respect to [Cr(III)-Gly-Phe]2+ is unity while it is fractional with respect to ninhydrin. Whereas, the values of rate constant (kψ) increase and leveling-off regions, like conventional single chain cetyltrimethylammonium bromide (CTAB) surfactant, were observed with geminis, later produces a third region of increasing kψ at higher gemini surfactant concentrations. This unusual third-region effect of the gemini micelles is assigned to changes in their micellar morphologies. The results obtained in micellar media were treated in terms of pseudo-phase model. The values of thermodynamic parameters (Ea, ΔH# and ΔS#) and binding constants (KA and KNin) have been evaluated. PMID:24878435

  7. Antigenotoxic and Apoptotic Activity of Green Tea Polyphenol Extracts on Hexavalent Chromium-Induced DNA Damage in Peripheral Blood of CD-1 Mice: Analysis with Differential Acridine Orange/Ethidium Bromide Staining

    María del Carmen García-Rodríguez


    Full Text Available This study was conducted to investigate the modulating effects of green tea polyphenols on genotoxic damage and apoptotic activity induced by hexavalent chromium [Cr (VI] in CD-1 mice. Animals were divided into the following groups: (i injected with vehicle; (ii treated with green tea polyphenols (30 mg/kg via gavage; (iii injected with CrO3 (20 mg/kg intraperitoneally; (iv treated with green tea polyphenols in addition to CrO3. Genotoxic damage was evaluated by examining micronucleated polychromatic erythrocytes (MN-PCEs obtained from peripheral blood at 0, 24, 48, and 72 h after treatment. Induction of apoptosis and cell viability were assessed by differential acridine orange/ethidium bromide (AO/EB staining. Treatment of green tea polyphenols led to no significant changes in the MN-PCEs. However, CrO3 treatment significantly increased MN-PCEs at 24 and 48 h after injection. Green tea polyphenols treatment prior to CrO3 injection led to a decrease in MN-PCEs compared to the group treated with CrO3 only. The average of apoptotic cells was increased at 48 h after treatment compared to control mice, suggesting that apoptosis could contribute to eliminate the DNA damaged cells induced by Cr (VI. Our findings support the proposed protective effects of green tea polyphenols against the genotoxic damage induced by Cr (VI.

  8. Use of cetyltrimethylammonium bromide as surfactant for the determination of copper and chromium in gasoline emulsions by electrothermal atomic absorption spectrometry

    In this work, the use of cetyltrimethylammonium bromide as surfactant for the preparation of oil-in-water emulsions for the determination of Cu and Cr in gasoline by electrothermal atomic absorption spectrometry (ET AAS) was evaluated. The surfactant amount was tested in the range of 25 to 300 mg, added to 2 ml of gasoline, and completed to 10 mL with 0.1% (v/v) nitric acid solution. 150 mg of surfactant was found optimum, and a sonication time of 10 min sufficient to form an oil-in-water emulsion that was stable for several hours. The ET AAS temperature program was established based on pyrolysis and atomization curves. The pyrolysis temperatures were set at 700 and 1300 deg. C for Cu and Cr, respectively and the selected atomization temperatures were 2400 and 2500 deg. C. The time and temperature of the drying stage and the atomization time were experimentally tested to provide optimum conditions. The limits of detection were found to be 5 μg L-1 and 1.5 μg L-1 for Cu and Cr, respectively in the original gasoline samples. The relative standard deviation (RSD) ranged from 4 to 9% in oil-in-water emulsions spiked with 5 μg L-1 and 15 μg L-1 of each metal, respectively. Recoveries varied from 90 to 98%. The accuracy of the proposed method was tested by an alternate procedure using complete evaporation of the gasoline sample. The method was adequate for the determination of Cu and Cr in gasoline samples collected from different gas stations in Salvador, BA, Brazil

  9. Methylnaltrexone bromide methanol monosolvate

    Xinbo Zhou


    Full Text Available In the title compound [systematic name: (4R,4aS,7aR,12bS-3-cyclopropylmethyl-4a,9-hydroxy-7-oxo-2,3,4,4a,5,6,7,7a-octahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-3-ium bromide methanol monosolvate], C21H26NO4+·Br−·CH3OH, two of the three six-membered rings adopt chair conformations while the third, which contains a C=C double bond, adopts an approximate half-boat conformation. The 2,3-dihydrofuran ring adopts an envelope conformation. In the crystal, the components are linked by O—H...O and O—H...Br hydrogen bonds. The absolute stereochemistry was inferred from one of the starting materials.

  10. Heterogeneous chromium catalysts


    The present invention relates to a heterogeneous chromium catalyst system for the polymerisation of ethylene and/or alpha olefins prepared by the steps of: (a) providing a silica-containing support, (b) treating the silica-containing support with a chromium compound to form a chromium-based silica-containing support, (c) activating the chromium-based silica-containing support, (d) chemically reducing the activated chromium-based silica-containing support to produce a precursor catalyst, (e) r...

  11. Hexavalent Chromium Workshop

    EPA is developing an updated IRIS assessment of hexavalent chromium. This assessment will evaluate the potential health effects of hexavalent chromium from oral and inhalation exposures. An important component of determining the cancer causing potential of ingested hexavalent chr...

  12. Chromium and Genomic Stability

    Wise, Sandra S.; Wise, John Pierce


    Many metals serve as micronutrients which protect against genomic instability. Chromium is most abundant in its trivalent and hexavalent forms. Trivalent chromium has historically been considered an essential element, though recent data indicate that while it can have pharmacological effects and value, it is not essential. There are no data indicating that trivalent chromium promotes genomic stability and, instead may promote genomic instability. Hexavalent chromium is widely accepted as high...

  13. Corrosion Behavior of Austenitic and Duplex Stainless Steels in Lithium Bromide

    Ayo Samuel AFOLABI


    Full Text Available The corrosion behavior of austenitic and duplex stainless steels in various concentrations of lithium, bromide solution was investigated by using the conventional weight loss measurement method. The results obtained show that corrosion of these steels occurred due to the aggressive bromide ion in the medium. Duplex stainless steel shows a greater resistance to corrosion than austenitic stainless steel in the medium. This was attributed to equal volume proportion of ferrite and austenite in the structure of duplex stainless steel coupled with higher content of chromium in its composition. Both steels produced electrochemical noise at increased concentrations of lithium bromide due to continuous film breakdown and repair caused by reduction in medium concentration by the alkaline corrosion product while surface passivity observed in duplex stainless steel is attributed to film stability on this steel.

  14. Oxidation of chromium telluride

    The authors study the interaction between chromium telluride and oxygen at elevated temperatures in view of its application in semiconductor technology. Thermodynamic analysis of the oxidation process and experimental data showed that the alloys of chromium telluride suffer oxidation in the presence of even traces of oxygen in a gaseous medium. Chromium telluride oxidation is a complex process that gives rise to various oxides and is accompanied by partial sublimation

  15. Oxidation of chromium telluride

    Pakhomovskaya, N.S.; Iorga, E.V.; Sheveleva, T.F.; Solov' eva, A.E.


    The authors study the interaction between chromium telluride and oxygen at elevated temperatures in view of its application in semiconductor technology. Thermodynamic analysis of the oxidation process and experimental data showed that the alloys of chromium telluride suffer oxidation in the presence of even traces of oxygen in a gaseous medium. Chromium telluride oxidation is a complex process that gives rise to various oxides and is accompanied by partial sublimation.

  16. Hair chromium concentration and chromium excretion in tannery workers.

    Saner, G; Yüzbasiyan, V; Cigdem, S


    Hair and urine samples were collected from 34 male tannery workers and from 12 normal adults. Eighteen of the workers dealt directly with chromium and the remaining 16 (controls) worked in the offices and kitchen of the same factory. All were found to be clinically healthy. Chromium was determined by flameless atomic absorption spectroscopy. When compared with normal adult values, urinary chromium concentration, Cr/Creatinine ratio, daily chromium excretion, and hair chromium, concentrations ...

  17. High-Purity Chromium Targets

    Rudoy, A.; Milman, Yu.; Korzhova, N.


    A procedure for producing large-scale chromium ingots by means of induction-arc melting was developed. From the high-purity, low-alloyed chromium ingots obtained, chromium targets were produced by of thermoplastic treatment techniques. The method of electron-beam evaporation of high-purity chromium was also used for production of targets.

  18. Conversion of Alcohols to Bromides by Trimethylsilane and lithium Bromide in Acetone

    Wei Feng; Zhang Xiao-xia; Zhang Qing; Wang Ji-yu; Chen Dai-mo


    Conversion of alcohols to alkyl bromides is one of the most frequently used functional group transformation reactions. Phosphorus tribromide is one of the most popular classical reagents.Triphenylphosphine has been used in combination with bromine,carbon tetrabromide,N-halo imides and other bromide compounds as a mild reagents for the preparation of alkyl bromides.More reacently, halotrimethylsilanes were found to be useful for halogenation of alcohols. George A.Olah successfully converted alcohols to bromides with chlorotrimethylsilane/lithium bromide in acetonitrile. But in our research, we found that we got no bromides but methylation products when we planed to convered our substances to bromides according to Gerge's method. We did some experiments, and we found that when the substituent group in the 2-N was donor group,we got the methylation products,but when it was acceptor group,the bromide could be got.(Scheme 1).Then we did some experiments with several other solvents, we found excitedly that when the solvent was acetone ,the bromides could be got even the substituent group was donor.(Scheme 2).When we changed the substances to normal alcohols ,such as ethyl alcohol,benzyl alcohol,isopropyl alcohol and 3,4-dimethoxy benzyl alcohol,we also got the bromides.In conclusion, we found a simple method to convert alcohols to bromides with trimethylsilane/li thium bromide in acetone,which was better than Geroge's method.

  19. Microstructural characterisation of chromium slags

    Burja, J.; F. Tehovnik; Vode, F.; Arh, B.


    In this chromium slags that form during melting of chromium alloyed steels are examined. During melting and oxidation of these steel grades a considerable amount of chromium is lost, and gained back with slag reduction. Laboratory experiments were performed to study the mechanism of chromium oxide reduction by silicon. Slags chemistry and phase composition have a strong effect on the steelmaking process. Phase analysis revealed two types of chromium oxides, calcium chromites and chromite spin...

  20. Substoichiometric extraction of chromium

    Substoichiometric extraction of chromium with tetraphenylarsonium chloride (TPACl), tri-n-octylamine (TNOA), diethylammonium diethyldithiocarbamate (DDDC) and ammonium pyrrolidinedithiocarbamate (APDC) was examined in detail. Chromium can be extracted substoichiometrically in a pH range, which is 1.1-2.6 for the TPACl compound, 0.6-2.3 for the TNOA compound, 5.1-6.4 for the DDDC chelate and 3.9-4.9 for the APDC chelate. Chromium in high-purity calcium carbonate, Orchard Leaves (NBS SRM-1571) and Brewers Yeast (NBS SRM-1569) was determined by neutron activation analysis combined with substoichiometric extraction by DDDC and APDC. The values of 2.0+-0.02 ppm and 2.6+-0.2 ppm were obtained for Brewers Yeast and Orchard Leaves, respectively. These values were in good agreement with those reported by NBS. The reaction mechanism and the reaction ratio between hexavalent chromium and dithiocarbamate are also discussed. (author)

  1. Chromium in diet

    ... Chromium deficiency may be seen as impaired glucose tolerance. It occurs in older people with type 2 ... PhD, and the A.D.A.M. Editorial team. Related MedlinePlus Health Topics Minerals Browse the Encyclopedia ...

  2. The carcinogenicity of chromium

    Norseth, Tor


    The carcinogenicity of chromium compounds is reviewed with specific attention to the gaps in knowledge for risk estimation and research needs. The most important problems at present are whether trivalent chromium compounds cause cancer, and whether there is a difference in cancer causing effects between the soluble and the slightly soluble hexavalent compounds in the practical exposure situation. Dose estimates for risk estimation based on epidemiological investigations are also lacking. Pres...

  3. Obtaining decorative chromium plating from trivalent chromium solutions

    Óscar Javier Suárez García


    The present work was aimed at a qualitative evaluation, in the laboratory, of different alternatives for assembling and operating a trivalent chromium bath for decorative chromium plating. Different chromium concentration solutions and different complexing agents were used. The initial result of this analysis was that chloride, formate and acetate solutions produced the best results. Solution preparation conditions were evaluated: temperature, chromium III complex formation time and also ...

  4. The analytical biochemistry of chromium.

    Katz, S A


    The essentiality and carcinogenicity of chromium depend on its chemical form. Oxidation state and solubility are particularly important in determining the biological effects of chromium compounds. For this reason, total chromium measurements are of little value in assessing its nutritional benefits or its toxicological hazards. Aqueous sodium carbonate-sodium hydroxide solutions have been successfully used for extracting hexavalent chromium from a variety of environmental and biological matri...

  5. Chromium in potatoes

    Chromium concentration in potatoes was determined, and tubes were labeled either intrinsically or extrinsically with radioactive chromate (51Cr). A labeled chromium complex was isolated from preparations of raw, baked, or fried potatoes and chromatographed on gel permeation media. Potato pulp and peel contained 1.63 and 2.70 μg of Cr/g tissue, respectively. There was no correlation between the two, nor did they respond similarly to changes of variety or locations. No significant differences were apparent in relative migration of the isolated complexes except between raw and cooked extrinsically labeled preparations

  6. 49 CFR 173.193 - Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc.


    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc. 173.193 Section 173.193 Transportation Other Regulations... bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc. (a) Bromoacetone must...

  7. Chromium and aging

    Aging is associated with increased blood glucose, insulin, blood lipids, and fat mass, and decreased lean body mass leading to increased incidences of diabetes and cardiovascular diseases. Improved chromium nutrition is associated with improvements in all of these variables. Insulin sensitivity de...

  8. Comparative Biosorption Studies of Hexavalent Chromium Ion onto Raw and Modified Palm Branches

    Mona A. Shouman; Nady A. Fathy; Soheir A. Khedr; Amina A. Attia


    The waste of palm branches (PB) was tested for its ability to remove chromium (VI) from aqueous solution by batch and column experiments. Palm branches chemically modified with an oxidizing agent (sulphuric acid) then coated with chitosan and surfactant (hexadecyl trimethyl ammonium bromide surfactant, HDTMA), respectively, were carried out to improve the removal performance of PB. The results of their Cr (VI) removal performances are pH dependent. The adsorption data could be well interprete...

  9. The metabolism of valethamate bromide, 1

    Valethamate bromide is widely used as a potent antispasmodic and antiulcerative agent. Studies were carried out to investigate the absorption, excretion and distribution of valethamate bromide in rats and men. When rats were given valethamate bromide-14C by subcutaneous injection, maximum blood concentration was reached at 1 to 2 hr after injection. The radioactivity was relatively highly distributed in kidney, liver, intestine and stomach. After subcutaneous injection, 57% of the administered dose was excreted in urine and 30% in feces within 48 hr. In the peroral administration, the transition of blood concentration levels did not present its peak clearly. Relatively high levels of radioactivity were present in stomach, intestine, kidney and liver. In the studies of biliary excretion used with unlabeled valethamate bromide, only when rats were administered by subcutaneous injection, 0.1 to 0.4% of the injected dose was recovered from the basic fraction of bile in 6 hr after injection. Our study revealed that there was difference between the urinary excretion rate of labeled and unlabeled valethamate bromide. And it was found that the transition of distributed amount into the tissues, which were abundant with lipid (as brain, fat and genitalia) and had the inclination to be distributed much in the second stage than in the first stage after administration, was not in proportion as blood concentrations. Consequently, it seems that valethamate bromide is partly metabolized to lipid-soluble compounds in body. When volunteers were administered Resitan by mouth, 2.7 to 5.5% of the dose was excreted in urine within 48 hrs. However, 42.5 to 47.5% of the administered dose was excreted in urine within 24 hr after intramuscular administration. Valethamate bromide was rapidly and virtually completely absorbed in both rats (s.c.) and men (i.m.), whereas 4 to 5% and 2.7 to 5.5% of the administered dose was excreted in rats and men after peroral administration. (author)

  10. Modeling and analysis of calcium bromide hydrolysis

    Lottes, Steven A.; Lyczkowski, Robert W.; Panchal, Chandrakant B.; Doctor, Richard D. [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)


    The main focus of this paper is the modeling, simulation, and analysis of the calcium bromide hydrolysis reactor stage in the calcium-bromine thermochemical water-splitting cycle for nuclear hydrogen production. One reactor concept is to use a spray of calcium bromide into steam, in which the heat of fusion supplies the heat of reaction. Droplet models were built up in a series of steps incorporating various physical phenomena, including droplet flow, heat transfer, phase change, and reaction, separately. Given the large heat reservoir contained in a pool of molten calcium bromide that allows bubbles to rise easily, using a bubble column reactor for the hydrolysis appears to be a feasible and promising alternative to the spray reactor concept. The two limiting cases of bubble geometry, spherical and spherical-cap, are considered in the modeling. Results for both droplet and bubble modeling with COMSOL MULTIPHYSICS trademark are presented, with recommendations for the path forward. (author)

  11. Studies of chromium gettering

    Preliminary results have shown that hydrogen pumping by chromium is a surface effect. Unlike with titanium, the getter material used in many present day tokamaks, there is no significant diffusion into the bulk. Additional experiments have been carried out to measure the basic characteristics of chromium films for gases of interest in tokamak research. These gases include deuterium, oxygen and nitrogen. A vacuum system is described which allowed precise control of the test gas, a constant wall temperature and determination of the projected getter surface area. A quadrupole mass spectrometer, rather than simply a total pressure gauge, was utilized to measure the partial pressure of the test gas as well as the residual gas composition in the system. A quartz crystal monitor was used to measure film thickness. Pumping speeds and sticking coefficients are given as a function of surface coverage for each test gas. A comparison will be made with titanium films deposited in the same vacuum system and under similar conditions

  12. Methyl bromide residues in fumigated cocoa beans with particular reference to inorganic bromide

    Inorganic bromide residues and 14C-labelled methylated products (expressed as CH3Br equivalent) in cocoa beans fumigated with [14C]-methyl bromide have been determined by radiometric and chemical methods. Determination of 14C by direct combustion in an oxygen chamber followed by liquid scintillation counting confirmed previous findings with respect to the magnitude, distribution and chemical nature of the residues. Although recovery of added bromide was good, the values of total bromide obtained by the chemical method were only half of those estimated from the total residual 14C-activity. This is attributed to loss of organic (presumably, protein-bound) bromide. In agreement with the total 14C-labelled residue contents, total bromide in shells was 20 times greater than that in nibs. The low levels of residues in the nib (12ppm as CH3Br equivalent, 10ppm Br) and the further reduction of organic residues by roasting suggest that no toxicological and nutritional hazards may be expected from fumigation of cocoa beans with methyl bromide. (author)

  13. Catalytic Spectrophotometric Determination of Chromium

    STOYANOVA, Angelina Miltcheva


    The catalytic effect of chromium(III) and chromium(VI) on the oxidation of sulfanilic acid by hydrogen peroxide was studied. The reaction was followed spectrophotometrically by measuring the absorbance of the reaction product at 360 nm. Under the optimum conditions 2 calibration graphs (for chromium(III) up to 100 ng mL-1, and for chromium(VI) up to 200 ng mL-1) were obtained, using the ``fixed time'' method with detection limits of 4.9 ng mL-1 and 3.8 ng mL-1, respectively...


    Suboptimal intakes of the essential nutrient, chromium, are characterized by elevated blood glucose, insulin resistance, obesity, hypertriglyceridemia, and low HDL. These are also signs and symptoms of the metabolic syndrome. Improvements due to increased intake of chromium are related to the degr...

  15. Groundwater contaminant by hexavalent chromium

    Parsons, C. [Univ. of Texas, Austin, TX (United States)


    Oxidation of trivalent chromium to hexavalent chromium has been investigated as a function of total manganese in soils as well as various incubation conditions. Chromium and manganese contents were analyzed by atomic absorption (graphite furnace and flame emission respectively) following acid digestion. Total hexavalent chromium generation capacity was determined by addition of 0.001 M CrCL3, incubation, and analysis by s-diphenyl carbazide. Samples were then leached with CaSO{sub 4} and MgSO{sub 4} and incubated in various environments (oven, freeze-drier, field moist, ultrafreeze) to test for geogenic generation of Cr(IV). The degree of geogenic generation of hexavalent chromium was compared with total Mn and Cr content as well as hexavalent generational capacity.

  16. Radiolytic reduction reaction of colloidal silver bromide solution

    The reduction reaction of colloidal silver bromide (AgBr3)2- in nitrous oxide gas saturated solution of some alcohols: methanol, ethanol, 2-propanol and 2-methyl-2-propanol by γ-irradiation was studied spectrophotometrically in order to elucidate the mechanism of the formation of colloidal silver bromide (AgBr3)3- at ambient temperature. The amount of colloidal silver bromide formed increases in the order: i-PrOH, EtOH, MeOH. In t-BuOH, colloidal silver bromide did not form. The relative reactivities of alcohols for colloidal silver bromide was also studied kinetically. (author)

  17. Role of paramagnetic chromium in chromium(VI)-induced damage in cultured mammalian cells.

    Sugiyama, M


    Chromium(VI) compounds are known to be potent toxic and carcinogenic agents. Because chromium(VI) is easily taken up by cells and is subsequently reduced to chromium(III), the formation of paramagnetic chromium such as chromium(V) and chromium(III) is believed to play a role in the adverse biological effects of chromium(VI) compounds. The present report, uses electron spin resonance (ESR) spectroscopy; the importance of the role of paramagnetic chromium in chromium(VI)-induced damage in intac...

  18. Methyl bromide residues in fumigated cocoa beans

    The 14C activity in unroasted [14C]-methyl bromide fumigated cocoa beans was used to study the fate and persistence of CH3Br in the stored beans. About 70% of the residues occurred in the shells. Unchanged CH3Br could not be detected, all the sorbed CH3Br having reacted with bean constituents apparently to form 14C-methylated derivatives and inorganic bromide. No 14C activity was found in the lipid fraction. Roasting decreased the bound (non-volatile) residues, with corresponding changes in the activities and amounts of free sugars, free and protein amino acids. Roasted nibs and shells showed a two-fold increase in the volatile fraction of the 14C residue. This fraction may be related to the volatile aroma compounds formed by Maillard-type reactions. (author)

  19. Removal of bromide and natural organic matter by anion exchange.

    Hsu, Susan; Singer, Philip C


    Bromide removal by anion exchange was explored for various water qualities, process configurations, and resin characteristics. Simulated natural waters containing different amounts of natural organic matter (NOM), bicarbonate, chloride, and bromide were treated with a polyacrylate-based magnetic ion exchange (MIEX) resin on a batch basis to evaluate the effectiveness of the resin for removal of bromide. While bromide removal was achieved to some degree, alkalinity (bicarbonate), dissolved organic carbon (DOC), and chloride were shown to inhibit bromide removal in waters with bromide concentrations of 100 and 300 microg/L. Water was also treated using a two-stage batch MIEX process. Two-stage treatment resulted in only a slight improvement in bromide removal compared to single-stage treatment, presumably due to competition with the high concentration of chloride which is present along with bromide in natural waters. In view of the relatively poor bromide removal results for the MIEX resin, a limited set of experiments was performed using polystyrene resins. DOC and bromide removal were compared by treating model waters with MIEX and two polystyrene resins, Ionac A-641 and Amberlite IRA910. The two polystyrene resins were seen to be more effective for bromide removal, while the MIEX resin was more effective at removing DOC. PMID:20045170

  20. [Research advances in methyl bromide in the ocean].

    Du, Hui-na; Xie, Wen-xia; Cui, Yu-qian; Chen, Jian-lei; Ye, Si-yuan


    Methyl bromide is an important atmospheric trace gas, which plays significant roles in the global warming and atmospheric chemistry. The ocean plays important and complex roles in the global biogeochemical cycles of methyl bromide, not only the source of atmospheric methyl bromide, but also the sink. Therefore, developing the chemical research of the soluble methyl bromide in the ocean, will not only have a certain guiding significance to the atmospheric ozone layer protection, but also provide a theoretical basis for estimating methyl bromide's contribution to the global environmental change on global scale. This paper reviewed the research advances on methyl bromide in the ocean, from the aspects of the biogeochemical cycle of methyl bromide in the ocean, the analysis and determination method, the concentration distribution, the sea-to-air flux and its sources and sinks in the atmosphere. Some deficiencies in the current studies were put forward, and the directions of the future studies were prospected. PMID:25876424

  1. Nitroethylation of vinyl triflates and bromides.

    Padilla-Salinas, Rosaura; Walvoord, Ryan R; Tcyrulnikov, Sergei; Kozlowski, Marisa C


    A two-carbon homologation of vinyl triflates and bromides for the synthesis of homoallylic nitro products is described. This palladium-catalyzed double coupling of nitromethane exploits the anion stabilizing and leaving group properties of nitromethane, generating the homo allyl nitro products via a tandem cross-coupling/π-allylation sequence. The resultant process provides a mild and convenient entry to nitroethylated products, which are versatile precursors to β,γ-unsaturated carbonyls, homoallylic amines, and nitrile oxides. PMID:23885976

  2. Bromate oxidized from bromide during sonolytic ozonation.

    Lu, Ning; Wu, Xue-Fei; Zhou, Ji-Zhi; Huang, Xin; Ding, Guo-Ji


    Sonolytic ozonation (US/O3) is an effective way to degrade many pollutants in drinking water as the elevated mass transfer rate of ozone gas and the enhanced forming of hydroxyl radicals (OH). This work investigated the formation of bromate (BrO3(-)) from bromide (Br(-)) in sonolytic ozonation. At neutral pH, the bromate conversion rate ([BrO3(-)]/[Br(-)]0) was increased to 60% by ultrasound at continuous ozone flow (0-0.2Lmin(-1)), much higher than that without ultrasound or without bubbling. This indicates that the promoting effect of sonolysis on BrO3(-) formation is mainly due to the sonolytic decomposition of ozone and the enhancement of gas-liquid transfer. The [BrO3(-)]/[Br(-)]0 was increased with increasing pH. In addition, the reduction of HOBr/OBr(-) with ultrasound demonstrates that bromate may be inhibited as the bromide was formed with the H2O2 generation under ultrasound. This suggests the competition between bromate and bromide during the US/O3 led to the inhibition of bromate formation at high ozone flow. Therefore, our result reveals that the bromate formation under ultrasound is improved remarkably in US/O3 in quick treatment with proper ozone flow (<0.2Lmin(-1)). PMID:24931426

  3. Fate and transport of chromium through soil

    Chromium chemistry relevant to the problem facing state of New Jersey (Usa) was examined. Transport of chromium through soil depends on its chemical forms. Transformation of chromium within bulk of soil depends on soil constituents, soil condition, such as pH, Eh and organic compounds applied onto soil or present in soil. Total chromium in soil can be determined. Speciation of chromium based on ionization, hydrolysis, complex formation, redox reactions and adsorption is predicted using MINIQ program

  4. Release of Chromium from Orthopaedic Arthroplasties

    Afolaranmi, G.A.; Tettey, J; Meek, R.M.D; Grant, M.H


    Many orthopaedic implants are composed of alloys containing chromium. Of particular relevance is the increasing number of Cobalt Chromium bearing arthroplasies being inserted into young patients with osteoarthritis. Such implants will release chromium ions. These patients will be exposed to the released chromium for over 50 years in some cases. The subsequent chromium ion metabolism and redistribution in fluid and tissue compartments is complex. In addition, the potential biological effects o...

  5. Chromium isotope variations

    D'Arcy, Joan Mary

    Chromium (Cr) stable isotopes are a useful tracer of changes in redox conditions because changes in its oxidation state are accompanied by an isotopic fractionation. For this reason the Cr isotope system is being developed as a potential tool for paleo-redox reconstruction. Dissolved Cr in seawater...... is incorporated into carbonates. Hence, ancient carbonates can potentially record the Cr isotopic composition (δ53Cr ‰) of seawater in the geological past. Reliable application and interpretation of this proxy requires a detailed knowledge about processes that fractionate Cr on the Earth’s surface......, and the quantification the Cr isotope composition of major Cr fluxes into and out of ocean. This thesis adds to the current knowledge of the Cr isotope system and is divided into two studies. The focus of the first study was to determine what processes control the Cr isotopic compositionof river...

  6. Recovery of Chromium Ions From Electroplating Wastewater by Flotation, Gamma Irradiation and Adsorption onto Hydrogels

    At present, the wastewater treatment facilities in many plating plants are approaching their time for replacement. On this occasion there is a strong requirement to re-evaluate the wastewater treatment measures from the point of view of treatment technology. Laboratory investigation was undertaken on the flotation of Cr (VI) from aqueous suspension over whole ph range, aiming at the separation of chromium by flotation. The cationic surfactant (hexadecyl triethyl ammonium bromide) was applied as a collector. Surface properties, in particular the critical micelle concentration, the effectiveness of surface tension reduction, efficiency, surface excess and the minimum surface area were measured at 30 μ C. The electro-flotation was applied with and without the collector at different times for the removal of chromium (VI). The results were discussed in term of surface properties of the collectors at the solution/air interface. Further work took place by irradiating the water samples by gamma- irradiation to reduce the highly toxic Cr(VI) to the much less toxic and less soluble Cr1 in water; therefore, there is a potential for the complete removal of chromium from aqueous solutions. The possibility of using hydrogels for the uptake of irradiated chromium solutions by different hydrogels was investigated. The structure of the hydrogels was estimated by using FT1R and the pore structure of the hydrogels before and after dictating with chromium ions was monitored by SEM. The adsorption studies show that, it is ph dependent. Lowering of the chromium concentration below the maximum permissible value have been achieved after the treatment of chromium solution by flotation, gamma irradiation and adsorption onto hydrogels

  7. Chromium reduction in Pseudomonas putida.

    Ishibashi, Y.; Cervantes, C; Silver, S


    Reduction of hexavalent chromium (chromate) to less-toxic trivalent chromium was studied by using cell suspensions and cell-free supernatant fluids from Pseudomonas putida PRS2000. Chromate reductase activity was associated with soluble protein and not with the membrane fraction. The crude enzyme activity was heat labile and showed a Km of 40 microM CrO4(2-). Neither sulfate nor nitrate affected chromate reduction either in vitro or with intact cells.

  8. Chromium reduction in Pseudomonas putida.

    Ishibashi, Y; Cervantes, C; Silver, S


    Reduction of hexavalent chromium (chromate) to less-toxic trivalent chromium was studied by using cell suspensions and cell-free supernatant fluids from Pseudomonas putida PRS2000. Chromate reductase activity was associated with soluble protein and not with the membrane fraction. The crude enzyme activity was heat labile and showed a Km of 40 microM CrO4(2-). Neither sulfate nor nitrate affected chromate reduction either in vitro or with intact cells. PMID:2389940

  9. [4-(Methoxycarbonylbenzyl]triphenylphosphonium bromide hemihydrate

    Shahid Hameed


    Full Text Available In the crystal structure of the title compound, C27H24O2P+·Br−·0.5H2O, there are intermolecular O—H...Br hydrogen bonds between the H atoms of the water of crystallization and the bromide anions. The three phenyl rings of the triphenylphosphonium moiety are at angles of 59.73 (15, 79.15 (14 and 82.81 (17° with the C/P/C planes.

  10. Exogenous bromide in the lactating rat influences iodine and bromide transfer to the suckling

    Pavelka, Stanislav

    Athens : University of Athens, 2005, s. 322-327. [International Symposium on Trace Elements in Human: New Perspectives /5./. Athens (GR), 13.10.2005-15.10.2005] Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * iodine * rat Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  11. Hydrogen permeation through chromium

    Steady state and non-steady state measurements of hydrogen permeation through metallic chromium are reported. The experiments have been conducted by use of hydrogen and deuterium within a pressure range of 10-8 - 1 bar and temperatures between 600 - 8000C. Numerical values for the physical quantities permeability, diffusion constant and solubility could be derived. At an upstream pressure above around 10-3 bar classical Sieverts-low was found (permeation rate proportional √p) with activation energies Qsub(perm) = 65 kJoule/mole, Qsub(Diff) = 4-8 kJoule/mole, Qsub(Sol) = 57-61 kJoule/mole for the respective processes involved. The isotopic effect between H and D of the permeabilities could be represented by a factor of 1,5 independence on temperature. All non steady-state measurements could be approximated reasonably well by classical diffusion kinetics. Below up-stream pressures of approx.= 10-7 bar the kinetics was no longer diffusion controlled, the dependence on up-stream pressure changed from √p -> p, the activation energy for permetation increased to 127 kJoule/mole and the isotopic factor resulted in about 2-3. (orig.)

  12. Trivalent chromium sorption on alginate beads

    Araújo, M. Manuela; Teixeira, J.A.


    The applicability of trivalent chromium removal from aqueous solutions using calcium alginate beads was studied. The equilibrium isotherms were plotted at two temperatures. The relationship between the chromium sorbed and the calcium released was determined as well as the effect of alginate amount and initial pH on the equilibrium results. Chromium sorption kinetics were evaluated as a function of chromium initial concentration and temperature. Transport properties of trival...

  13. Bromism from daily over intake of bromide salt.

    Frances, C; Hoizey, G; Lamiable, D; Millart, H; Trenque, T


    Bromide intoxication today is an infrequent disease, but preparations containing bromide are still available in nonprescription compounds, on the French market. We report a casewith bromide intoxication due to daily over intake (approximately 20 tablets per day; i.e. total elemental bromide intake approximately 6 g/day) of calcium bromo-galactogluconate (Calcibronat) for 1.5 months. A 30-year-old woman with a long history of psychotropic drug abuse was hospitalized in a psychiatric department for neuropsychological manifestations. She presented a seriously disturbed mental status with confusion, disorientation, auditory and visual hallucinations, and loss of short-time memory. A markedly increased serum bromide level of 1717 mg/L (21.5 mEq/L) measured on the first day after her admission confirmed the diagnosis of chronic bromism suspected based on her symptomatology. During her hospitalization, bromide plasma concentrations were measured and monitored using inductively coupled plasma mass spectrometry, a sensitive and very specific method. After withdrawal of the drug, the symptoms improved within 8 days. Serial bromide concentrations gradually declined throughout nearly 2 months of monitoring, until she was discharged from the hospital. We found an elimination half-life of bromide in blood of approximately of 10 days. This case demonstrates that, while today bromism occurs infrequently, it should still be included in the differential diagnosis of neuropsychiatric symptoms. PMID:12733857

  14. On texture formation of chromium electrodeposits

    Nielsen, Christian Bergenstof; Leisner, Peter; Horsewell, Andy


    The microstructure, texture and hardness of electrodeposited hard, direct current (DC) chromium and pulsed reversed chromium has been investigated. These investigations suggest that the growth and texture of hard chromium is controlled by inhibition processes and reactions. Further, it has been...

  15. Evaluation of N-ethyl-N-methyl-morpholinium bromide and N-ethyl-N-methyl-pyrrolidinium bromide as bromine complexing agents in vanadium bromide redox flow batteries

    Evolution of bromine gas in the positive half cell of the Generation 2 (G2) vanadium bromide (V/Br) battery during charging is a concern which can be resolved by the use of bromine complexing agents. In this paper, for the first time, we report the effect of the addition of two quaternary ammonium bromides; N-ethyl-N-methyl-morpholinium bromide (MEM) and N-ethyl-N-methyl-pyrrolidinium bromide (MEP) to the positive and negative half cell electrolytes of the V/Br. Cyclic voltammetry (CV), linear sweep voltammetry and electrochemical impedance spectroscopy (EIS) studies showed that the addition of MEM–MEP effectively reduce Br2 vapours. Although the presence of MEM and MEP did not affect the mechanism of the electrode reactions, performance tests conducted in lab scale V/Br cells employing the VF11 cation exchange membrane resulted in lower average cell efficiencies possibly due to the increase in membrane resistance caused by membrane fouling

  16. Glycopyrronium bromide for the treatment of chronic obstructive pulmonary disease.

    Riario-Sforza, Gian Galeazzo; Ridolo, Erminia; Riario-Sforza, Edoardo; Incorvaia, Cristoforo


    Glycopyrronium bromide is a new long-acting muscarinic antagonist to be used once-daily, which is approved as a bronchodilator for the symptomatic maintenance treatment of adult patients with chronic obstructive pulmonary disease (COPD). In the Glycopyrronium bromide in chronic Obstructive pulmonary disease airWays trials, treatment with inhaled glycopyrronium bromide at 50 μg once daily achieved a significantly better lung function than placebo, as measured by the trough forced expiratory volume in 1 s in patients with moderate-to-severe COPD. The lung function improvement was maintained for up to 52 weeks. Other improved indexes were dyspnea scores, health status, exacerbation rates and time of exercise endurance. Studies comparing the efficacy of glycopyrronium versus tiotropium bromide found substantial equivalence of the two drugs. Glycopyrronium was generally well tolerated. These data add inhaled glycopyrronium bromide to the treatment of patients with moderate to severe COPD as an effective once-daily LAMA. PMID:25547422

  17. Kinetic spectrophotometric determination of bromide in clidinium-c drug

    Ali Sheibani; M. Reza Shishehbore; Zahra Tavakolian Ardakani


    A simple, rapid and sensitive method has been described for the determination of the trace amounts of bromide. The method is based on the catalytic effect of bromide ion on the oxidation of methylene blue by bromate in sulfuric acid media. The reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of methylene blue at 665 nm. Bromide was determined in the range of 0.05-1.90 μg/mL with the detection limit of 0.03 μg/mL. The relative standard deviations of five replicate determinations of 0.20 and 10.0 μg/mL of bromide were 2.4% and 1.8%, respectively. The influence of potential interfering ions and substances was studied. The method is applied to the analysis of bromide in clidinium-c tablet as a real sample.

  18. Chromium Salen Mediated Alkene Epoxidation

    Petersen, Kaare Brandt; Norrby, Per-Ola; Daly, Adrian M.; Gilheany, Declan G.


    The mechanism of alkene epoxidation by chromium(v) oxo salen complexes has been studied by DFT and experimental methods. The reaction is compared to the closely related Mn-catalyzed process in an attempt to understand the dramatic difference in selectivity between the two systems. Overall, the......-spin surface. The low-spin addition of metal oxo species to an alkene leads to an intermediate which forms epoxide either with a barrier on the low-spin surface or without a barrier after spin inversion. Supporting evidence for this intermediate was obtained by using vinylcyclopropane traps. The chromium...

  19. Chromium content of selected Greek foods.

    Bratakos, Michael S; Lazos, Evangelos S; Bratakos, Sotirios M


    The total chromium content of a wide variety of Greek foods was determined by graphite furnace atomic absorption spectroscopy (GFAAS). Meat, fish and seafood, cereals and pulses were rich sources of chromium (>0.100 microg/g). Fruits, milk, oils and fats and sugar were poor sources. Differences in chromium content were found between different food classes from Greece and those from some other countries. Based on available food consumption data and chromium levels in this study, it was estimated that the chromium intake of Greeks is 143 microg/day, with vegetables, cereals and meat being the main contributors. PMID:12083715

  20. Determination of chromium combined with DNA, RNA and protein in chromium-rich brewer's yeast

    The contents of chromium in the DNA, RNA and protein fractions separated from chromium-rich and normal brewer's yeast were determined with the neutron activation analysis in order to study the combination of Cr with DNA, RNA and protein in chromium-rich brewer's yeast. The results showed that the extracting rats and concentrations of DNA, RNA and protein had no significant difference in two types of yeast, but the chromium contents of DNA, RNA and protein in the chromium-rich yeast were significantly higher than those in the normal. In addition, the content of chromium in DNA was much higher than that in RNA and protein, which indicated that the inorganic chromium compounds entered into the yeast cell, during the yeast cultivation in the culture medium containing chromium were converted into organic chromium compounds combined with DNA, RNA and protein

  1. Selective oxidation of bromide in wastewater brines from hydraulic fracturing.

    Sun, Mei; Lowry, Gregory V; Gregory, Kelvin B


    Brines generated from oil and natural gas production, including flowback water and produced water from hydraulic fracturing of shale gas, may contain elevated concentrations of bromide (~1 g/L). Bromide is a broad concern due to the potential for forming brominated disinfection byproducts (DBPs) during drinking water treatment. Conventional treatment processes for bromide removal is costly and not specific. Selective bromide removal is technically challenging due to the presence of other ions in the brine, especially chloride as high as 30-200 g/L. This study evaluates the ability of solid graphite electrodes to selectively oxidize bromide to bromine in flowback water and produced water from a shale gas operation in Southwestern PA. The bromine can then be outgassed from the solution and recovered, as a process well understood in the bromine industry. This study revealed that bromide may be selectively and rapidly removed from oil and gas brines (~10 h(-1) m(-2) for produced water and ~60 h(-1) m(-2) for flowback water). The electrolysis occurs with a current efficiency between 60 and 90%, and the estimated energy cost is ~6 kJ/g Br. These data are similar to those for the chlor-alkali process that is commonly used for chlorine gas and sodium hydroxide production. The results demonstrate that bromide may be selectively removed from oil and gas brines to create an opportunity for environmental protection and resource recovery. PMID:23726709

  2. Sodium bromide acts as a contrast material on DEXA scanning.

    Chaisson, T G; Ryan, D H


    Subjects undergoing a series of procedures to determine body composition, including dual-energy x-ray absorptiometry (DEXA) scanning and extracellular water volume determination by bromide dilution, demonstrated abnormal DEXA scans in some cases. Oral doses of sodium bromide in the stomach were detected on total body DEXA scanning as contrast material. The physical principles that cause bromide to be imaged in a manner similar to calcium by the DEXA scanner are discussed so that other investigators may be aware of this potential pitfall in body composition analysis. PMID:8195668

  3. Tissues and urinary chromium concentrations in rats fed high-chromium diets

    Complete text of publication follows. Chromium is an essential trace elements and enhances the function of insulin as a form of chromodulin. In the subjects with a certain type of diabetics, 200 to 1,000 μg/d of chromium is administered to reduced the symptoms of diabetics. However, although there are not any health-promotive effects of chromium-administration in healthy subjects, various types of chromium supplements are commercially available in many countries; the adverse effects caused by an excessive chromium intake are feared. In the present study, to clarify the tolerable upper limit of chromium, tissue and urinary chromium concentrations, liver function and iron status were examined in rats fed high-chromium diets. Thirty-six male 4-weeks Wistar rats were divided into six groups and fed casein-based diets containing 1, 10 or 100 μg/g of chromium as chromium chloride (CrCl3) or chromium picolinate (CrPic) for 4 weeks. After the feeding, chromium concentrations in liver, kidney, small intestine and tibia were determined by inductively coupled plasma-mass spectrometry. In addition, urine samples were collected on 3rd to 4th week and their chromium concentrations were also determined. Chromium concentrations in liver, kidney, small intestine and tibia were elevated with increase of dietary chromium concentration. Urinary chromium excretion was also elevated with the increase of dietary chromium and the rate of urinary chromium excretion was less than 2% to dietary chromium intake in all the experimental groups. In the administration of 100 μg/g of chromium, rats given CrCl3 showed significantly higher tibia chromium concentration and lower urinary chromium excretion than those given CrPic. There were not any differences in iron status among the experimental groups. Activities of serum aspartate aminotransferase and alanine aminotransferase in rats fed diet containing 100 μg/g of chromium as CrPic were significantly higher than those in rats fed other diets.

  4. A new convenient access to highly functionalized ()-2-arylvinyl bromides

    Yubo Jiang; Chunxiang Kuang


    Highly functionalized ()-2-arylvinyl bromides were prepared in high yields through a new convenient access by acylation of ()-4-(2-bromovinyl)phenol with fatty and aromatic acids at room temperature using dicyclohexyl carbodiimide (DCC) and dimethylaminopyridine (DMAP).

  5. Kinetics and Mechanism of the Chlorate-Bromide Reaction.

    Sant'Anna, Rafaela T P; Faria, Roberto B


    The chlorate-bromide reaction, ClO3(-) + 6Br(-) + 6H(+) → 3Br2 + Cl(-) + 3H2O, was followed at the Br3(-)/Br2 isosbestic point (446 nm). A fifth-order rate law was found: (1)/3 d[Br2]/dt = k[ClO3(-)][Br(-)][H(+)](3) (k = 5.10 × 10(-6) s(-1) L(4) mol(-4)) at 25 °C and I = 2.4 mol L(-1). At high bromide concentrations, the bromide order becomes close to zero, indicating a saturation profile on bromide concentration, similar to the chloride saturation profile observed in the chlorate-chloride reaction. A mechanism is proposed that considers the formation of the intermediate BrOClO2(2-), similar to the intermediate ClOClO2(2-) proposed in the mechanism of the chlorate-chloride reaction. PMID:26467822

  6. Methyl Bromide: Effective Pest Management Tool and Environmental Threat

    Thomas, W. B.


    Methyl bromide is used extensively on a global basis as a pesticide against nematodes, weeds, insects, fungi, bacteria, and rodents. As a soil fumigant, it is used in significant quantities in the production of strawberry and tomato, as well as other agriculture commodities. Grain, fresh fruit, forestry products, and other materials are fumigated with methyl bromide to control pest infestations during transport and storage. Structures also are treated with this chemical to control wood-destro...

  7. Quantum Chemistry Study on Dissociation of Oxalyl Bromide


    The multi-bond dissociation dynamics of oxalyl bromide ((BrCO)2) has been investigated by DFT and CIS calculations. Upon the results, conclusion could be drawn that dissociation of C-Br bond of oxalyl bromide at the ground state (S0) is of barrierless. After the absorption of a photon, (BrCO)2 is excited to the first excited state and one of its C-Br bonds is broken to yield dissociate.

  8. Effects of ipratropium bromide and fenoterol aerosols in pulmonary emphysema.

    Hughes, J A; Tobin, M. J.; Bellamy, D; Hutchison, D. C.


    In patients with radiological evidence of pulmonary emphysema the bronchodilator drugs fenoterol and ipratropium bromide produced a considerable increase in vital capacity and reduction in residual volume. The response to fenoterol was virtually complete 15 minutes after administration, but after ipratropium bromide vital capacity was still increasing at 60 minutes. The change in vital capacity was slightly greater with a combination of the two drugs than with either used alone. Changes in FE...

  9. Food Chromium Contents, Chromium Dietary Intakes And Related Biological Variables In French Free-Living Elderly

    Chromium (Cr III), an essential trace element, functions in potentiating insulin sensitivity, regulating glucose homeostasis, improving lipid profile, and maintaining lean body mass. Glucose intolerance and chromium deficiency increase with age, and could be aggravating factors of the metabolic synd...

  10. Soils contaminated with hexavalent chromium

    Fonseca, Bruna Catarina da Silva


    Tese de doutoramento em Engenharia Química e Biológica The interest in environmental soil science has been growing in the last years due to the continuous degradation of this major natural resource. With this in mind, and because chromium and lead are two of the most toxic heavy metals frequently detected as soil contaminants in the Portuguese territory, the study and development of few remediation techniques and the indissociable description of the sorption and migration of...

  11. Carbon, chromium and molybdenum contents

    This work describes solidification experiments on white cast iron, with 15 and 20% of chromium, 2.3, 3.0 and 3.6 % of carbon and 0.0, 1.5 and 2.5 % of molybdenum in test de samples with 30 mm diameter. Measurements were performed on the austenite and eutectic formation arrests, the number of the eutectic carbide particles relative to the total and the eutectic volumes, and the volume fraction of the primary austenite

  12. Performance of large lanthanum bromide scintillators

    Cerium-doped lanthanum bromide, LaBr3(Ce), scintillator possesses several outstanding properties that make it an attractive choice for security, medical, and geophysical radiation detection applications. Among these properties are good density (5.1 g/cc), excellent energy resolution (∼3% full-width at half-maximum (FWHM) at Eγ=662 keV), brightness (>65,000 photon/MeV), and speed, (τd100 cc). The anisotropic thermal expansion exhibited by this material makes it difficult to grow large ingots due to the build up of internal stresses as it cools, causing fracturing. Recently, Saint-Gobain Crystals has achieved successful growths of large unfractured ingots, from which large detectors have been assembled (>150 cc). The outstanding properties seen in small pieces are retained up to at least 155 cc (the largest assembled into a single detector thus far). A cylindrical LaBr3(Ce=5%) crystal with dimensions of diameter=51 mm, and length=76 mm achieves energy resolution of 3.1% FWHM at 662 keV, and brightness of 165% of NaI with good uniformity throughout the crystal. Scintillation light yield and energy resolution have been examined as a function of crystal size and γ-ray energy. Spatial mapping of a large crystal was examined and shown to be uniform. Large crystals enable accurate measurements of the intrinsic γ-ray background from 138La (0.09% nat. abun., γ-ray emission at 1436 and 789 keV). This background is shown to scale appropriately in size with theoretical calculations

  13. Preparation and Characterization of Nanocrystalline Hard Chromium Coatings Using Eco-Friendly Trivalent Chromium Bath

    V. S. Protsenko; V. O Gordiienko; Danilov, F. I.; Kwon, S.C.


    A new aqueous sulfate trivalent chromium bath is described. The chromium bath contains formic acid and carbamide as complexing agents. Chromium was deposited at a temperature of 30÷40 oC and a cathode current density of 10÷25 A dm-2. The bath allows obtaining thick (up to several hundred micrometers) hard chromium coatings with nanocrystalline structure. The electrodeposition rate reaches 0.8÷0.9 µm min-1.


    A. R. Asgari ، F. Vaezi ، S. Nasseri ، O. Dördelmann ، A. H. Mahvi ، E. Dehghani Fard


    Removal of chromium can be accomplished by various methods but none of them is cost-effective in meeting drinking water standards. For this study, granular ferric hydroxide was used as adsorbent for removal of hexavalent chromium. Besides, the effects of changing contact time, pH and concentrations of competitive anions were determined for different amounts of granular ferric hydroxide. It was found that granular ferric hydroxide has a high capacity for adsorption of hexavalent chromium from ...

  15. Inoculation of chromium white cast iron

    D. Kopyciński


    Full Text Available It has been proved that an addition of boron carbide introduced as an inoculant to the chromium white cast iron changes the structureof castings. Castings after inoculation revealed a different structure with numerous grains. Primary precipitates of chromium carbide also appeared, reducing the mechanical properties of as-cast parts. Properly established heat treatment regime makes chromium iron castings regain their, originally high, mechanical properties.

  16. Inoculation of chromium white cast iron

    D. Kopyciński


    It has been proved that an addition of boron carbide introduced as an inoculant to the chromium white cast iron changes the structureof castings. Castings after inoculation revealed a different structure with numerous grains. Primary precipitates of chromium carbide also appeared, reducing the mechanical properties of as-cast parts. Properly established heat treatment regime makes chromium iron castings regain their, originally high, mechanical properties.

  17. Assessment of Ethidium bromide and Ethidium monoazide bromide removal from aqueous matrices by adsorption on cupric oxide nanoparticles.

    Fakhri, Ali


    The present study was undertaken to develop an effective adsorbent and to study the adsorption of Ethidium bromide and Ethidium monoazide bromide from aqueous solution using the CuO nanoparticles. The characteristics of CuO nanoparticles were determined and found to have a surface area 89.59m(2)/g. Operational parameters such as pH, contact time and adsorbent concentration, initial concentration and temperature were also studied. The amount of removal increases with the increase in pH from one to seven and reaches the maximum when the pH is nine. Adsorption data fitted well with the Langmuir, Freundlich and Florry-Huggins models. The results show that the best fit was achieved with the Langmuir isotherm equation with maximum adsorption capacities of 0.868 and 0.662mg/g for Ethidium bromide and Ethidium monoazide bromide, respectively. The adsorption process was found to follow pseudo-second-order kinetics. The calculated thermodynamic parameters, namely ΔG, ΔH and ΔS showed that adsorption of Ethidium bromide and Ethidium monoazide bromide was spontaneous and endothermic under examined conditions. PMID:24630576

  18. Determination of chromium, cobalt and nickel in tissue samples by radiochemical activation analysis

    A radiochemical neutron activation analysis method for the determination of chromium, cobalt and nickel in tissue samples. A radiochemical neutron activation analysis method for the determination of chromium, cobalt and nickel has been developed. The destruction device used consisted of a combined wet-ashing-distillation and ion-exchange system. Six samples could be treated at the same time. The samples were wet-ashed with H*L2SO*L4-H*L2O*L2 mixture. Volatile elements were distilled as bromide compounds with HBr*H-. The distillation residue in 8M HCl was passed through hydrated antimony pentoxide (HAP) in order to remove disturbing *H2*H4Na-activity and through a Dowex 2 x 8 column so as to retain *H6*H0Co (formed from *H5*H8Ni). Chromium was elutriated from the column and precipitated as Cr(OH)*L3 for the removal of disturbing *H3*H2P-activity. The standards and samples were treated in a similar manner each so that the yield determination is not necessarily needed. The yields by tracer experiments were (43 +- 5) % for Cr, (93 +- 4) % for Co and (88 +- 14) % for Ni. The precision and accuracy of the method were studied by using reference materials of the National Bureau of Standards (NBS) and the International Atomic Energy Agency (IAEA)

  19. Permeation of chromium salts through human skin in vitro

    Gammelgaard, Bente; Fullerton, A; Avnstorp, C;


    of the dichromate solution. Chromium skin levels increased with increasing concentrations of applied chromium salts up to 0.034 M Cr. The amount of chromium in recipient phase and skin layers increased with increasing pH when the applied solution contained potassium dichromate. This was ascribed to a decreased skin...... barrier function of the skin. The amount of chromium found in all skin layers after application of chromium chloride decreased with increasing pH due to lower solubility of the salt. The % of chromium found in the recipient phase as chromium(VI) increased with increasing total chromium concentration...... indicating a limited reduction ability of the skin in vitro....

  20. Chromium in aqueous nitrate plutonium process streams: Corrosion of 316 stainless steel and chromium speciation

    This study was undertaken to determine if chromium(+6) could exist in plutonium process solutions under normal operating conditions. Four individual reactions were studied: the rate of dissolution of stainless steel, which is the principal source of chromium in process solutions; the rate of oxidation of chromium(+3) to chromium(+6) by nitric acid; and the reduction of chromium(+6) back to chromium(+3) by reaction with stainless steel and with oxalic acid. The stainless steel corrosion rate was found to increase with increasing nitric acid concentration, increasing hydrofluoric acid concentration, and increasing temperature. Oxidation of chromium(+3) to chromium(+6) was negligible at room temperature and only became significant in hot concentrated nitric acid. The rate of reduction of chromium(+6) back to chromium(+3) by reaction with stainless steel or oxalic acid was found to be much greater than the rate of the reverse oxidation reaction. Based on these findings and taking into account normal operating conditions, it was determined that although there would be considerable chromium in plutonium process streams it would rarely be found in the (+6) oxidation state and would not exist in the (+6) state in the final process waste solutions

  1. Selectivity of the adsorption process of modified zeolite rock with hexadecyl trimethylammonium bromide in front to chromates and dichromates

    In the present investigation natural zeolite (clinoptilolite) from the Chihuahua state, which was conditioned with sodium chloride solution and subsequently modified with a hexadecyl trimethylammonium bromide solution was used to evaluate the removal of Cr (Vi) from chromate or dichromate solutions. The zeolite materials were characterized by scanning electron microscopy and X-ray diffraction. The surface area was also determined. The experiments were performed in a batch system, the influence of ph, contact time between phases were investigated and during the adsorption process was calculated the concentration of chromium ion present in aqueous solution (CrO42-, Cr2O72-). The quantification of chromium removed from the aqueous solution by atomic absorption spectrometry technique was done. In order to understand the behaviour of the adsorption kinetics the pseudo first and pseudo second order models were applied, and to determine the adsorption capacity of the zeolite materials for Cr the Langmuir, Freundlich and Langmuir-Freundlich models were chosen. It was found that the removal efficiency of chromium ion is influenced by ph and the chemical species present: chromate or dichromate. The chromate and dichromate sorption kinetic data were best fitted to the pseudo-second and pseudo-first order models, respectively; and the Langmuir and Langmuir-Freundlich models described adequately the isotherms data considering a mono component system. In a mixture of Cr (Vi) ad CrO42- and Cr2O72-, the surfactant modified zeolite has a greater selectivity for Cr2O72- ion than CrO42-. In this case the Langmuir-Freundlich model described the adsorption isotherm behavior. (Author)

  2. Alkane dehydrogenation over supported chromium oxide catalysts

    Weckhuysen, B.M.; Schoonheydt, R.A.


    The dehydrogenation of alkanes over supported chromium oxide catalysts in the absence of oxygen is of high interest for the industrial production of propene and isobutene. In this review, a critical overview is given of the current knowledge nowadays available about chromium-based dehydrogenation ca

  3. Interaction of cephradine monohydrate with Cetyldimethylethylammonium Bromide

    Highlights: • We carry out the interaction of CDM drugs with CDMEAB conductometrically. • We examine the effect of drugs on the critical micelle concentration of CDMEAB. • Two critical micelle concentrations are obtained for drug-CDMEAB system. • Electrostatic and hydrophobic interactions between drug and surfactant are proposed. • Effect of KCl and K2SO4 is observed on interaction between drug and surfactant. -- Abstract: Interaction of cephradine monohydrate (CDM) with Cetyldimethylethylammonium Bromide (CDMEAB) has been studied by conductance measurements in pure form and in the presence of salts like potassium chloride (KCl) and potassium sulphate (K2SO4) over the temperature range of (298.15 to 318.15) K. From conductivity vs. surfactant concentration plots, two critical micelle concentrations like c1∗ and c1∗ were obtained for (CDM + CDMEAB) systems. The variation of c∗ values of CDMEAB in the presence of CDM is the indication of the interaction between CDM and CDMEAB. For the (CDM + CDMEAB) system, the values of c∗ values are higher in magnitude in contrast to that of pure CDMEAB in water over the range in temperature studied. In aqueous solutions of KCl and K2SO4, the c∗ values are changed with the increase of the concentration of salts and hence the micellization is dependent on salt concentration. The ΔGm0 values were negative and the spontaneity of micellization process is found to be increased with increase of temperature. The values of ΔH1,m0 and ΔS1,m0 indicated that the drug mediated CDMEAB aggregation in water was controlled at lower temperatures while at higher temperatures the aggregation was both enthalpy and entropy controlled. The ΔH2,m0 and ΔS2,m0 values revealed that the micellization in water was both enthalpy and entropy controlled at lower and higher temperatures though the effect of entropy at middle temperature was dominant. The results indicated that binding interactions between CDM and CDMEAB are both

  4. Intensification of sonochemical degradation of malachite green by bromide ions.

    Moumeni, Ouarda; Hamdaoui, Oualid


    Sonochemical oxidation has been investigated as a viable advanced oxidation process (AOP) for the destruction of various pollutants in water. Ultrasonic irradiation generates ()OH radicals that can recombine, react with other gaseous species present in the cavity, or diffuse out of the bubble into the bulk liquid medium where they are able to react with solute molecules. The extent of degradation of an organic dye such as malachite green (MG) is limited by the quantity of hydroxyl radicals diffused from cavitation bubbles. In this work, the effect of bromide ions on sonolytic degradation of MG was investigated. The obtained results clearly demonstrated the considerable enhancement of sonochemical destruction of MG in the presence of bromide. No significant differences were observed in the presence of chloride and sulfate, excluding the salting-out effect. Positive effect of bromide ions, which increases with increasing bromide level and decreasing MG concentration, is due to the generation of dibromine radical anion (Br(2)(-)) formed by reaction of Br(-) with ()OH radicals followed by rapid complexation with another anion. The generated Br(2)(-) radicals, reactive but less than ()OH, are likely able to migrate far from the cavitation bubbles towards the solution bulk and are suitable for degradation of an organic dye such as MG. Additionally, Br(2)(-) radicals undergo radical-radical recombination at a lesser extent than hydroxyl radicals and would be more available than ()OH for substrate degradation, both at the bubble surface and in the solution bulk. This effect compensates for the lower reactivity of Br(2)(-) compared to ()OH toward organic substrate. Addition of bromide to natural and sea waters induces a slight positive effect on MG degradation. In the absence of bromide, ultrasonic treatment for the removal of MG was promoted in complex matrices such as natural and sea waters. PMID:21911308

  5. Oxidation of manganese(II) during chlorination: role of bromide.

    Allard, S; Fouche, L; Dick, J; Heitz, A; von Gunten, U


    The oxidation of dissolved manganese(II) (Mn(II)) during chlorination is a relatively slow process which may lead to residual Mn(II) in treated drinking waters. Chemical Mn(II) oxidation is autocatalytic and consists of a homogeneous and a heterogeneous process; the oxidation of Mn(II) is mainly driven by the latter process. This study demonstrates that Mn(II) oxidation during chlorination is enhanced in bromide-containing waters by the formation of reactive bromine species (e.g., HOBr, BrCl, Br2O) from the oxidation of bromide by chlorine. During oxidation of Mn(II) by chlorine in bromide-containing waters, bromide is recycled and acts as a catalyst. For a chlorine dose of 1 mg/L and a bromide level as low as 10 μg/L, the oxidation of Mn(II) by reactive bromine species becomes the main pathway. It was demonstrated that the kinetics of the reaction are dominated by the adsorbed Mn(OH)2 species for both chlorine and bromine at circumneutral pH. Reactive bromine species such as Br2O and BrCl significantly influence the rate of manganese oxidation and may even outweigh the reactivity of HOBr. Reaction orders in [HOBr]tot were found to be 1.33 (±0.15) at pH 7.8 and increased to 1.97 (±0.17) at pH 8.2 consistent with an important contribution of Br2O which is second order in [HOBr]tot. These findings highlight the need to take bromide, and the subsequent reactive bromine species formed upon chlorination, into account to assess Mn(II) removal during water treatment with chlorine. PMID:23859083

  6. Neutron scattering and models: Chromium

    Differential neutron elastic-scattering cross sections of elemental chromium are measured from 4.5 ∼ 10 MeV in steps of ∼ 0.5 MeV and at ≥ 40 scattering angles distributed between ∼ 17 degree--160 degree. Concurrently differential cross sections for the inelastic neutron excitation of the yrast 2+ (1.434 MeV) level in d52Cr are determined. In addition, broad inelastically-scattered neutron groups are observed corresponding to composite excitation of levels up to ∼ 5.5 MeV in the various chromium isotopes. These experimental results are combined with low-energy values previously reported from this laboratory, with recent ∼ 8 → 15 MeV data measured at the Physikalisch-Technische Bundesanstalt and with a 21.6 MeV result from the literature to form an extensive neutron-scattering data base which is interpreted in the context of spherical-optical and coupled-channels (rotational and vibrational) models. These models reasonably describe the observables but indicate rather large energy-dependent parameter trends at low energies similar to those previously reported near the peak of the So strength function in studies at this laboratory. The physical implications of the measurements and models are discussed including deformation, coupling, dispersive and asymmetry effects

  7. Radioactive bromide partition test in the diagnosis of tuberculous meningitis

    The utility of the radioactive bromide partition test in differentiating tuberculous meningitis (TBM) from other forms of meningitis has been assessed. The test was carried out in 19 patients with TBM, 6 patients with partially treated pyogenic meningitis and 17 non-meningitis controls. Eighteen of the 19 TBM patients gave bromide partition ratio (BPR) value below 1.3 while the value was above this level in all control patients including partially treated meningitis. The results indicate that the test is useful in the differential diagnosis of TBM. (author)

  8. Chemistry of pyrrolizines; reactions with cyanogen bromide and trifluoroacetic anhydride

    Verboom, W.; Visser, G.W.; Reinhoudt, D.N.


    Interaction of the pyrrolizine 3 with cyanogen bromide in a tetrahydrofuran/water mixture affords addition to the enamine double bond with formation of 5 which can be aromatized to 6 by silica gel. Reaction of 6 with cyanogen bromide in the same solvent mixture yields the indoline 8a which structure is proved in a chemical way by conversion of the product into the aldehyde 8d. The different reaction pathway is discussed in terms of steric hindrance by the ester groups. Treatment of 6 with tri...

  9. Stability analysis for complexes in calcium-alkali bromide solutions

    We discuss the dependence of the stability of tetrahedral complexes in molten halide mixtures on the halogen species. This is done by calculating the equilibrium concentration of (CaBr4)2- complexes in calcium-alkali bromide solutions as a function of composition, in comparison with earlier calculations on the calcium-alkali chloride systems. The comparison supports a possible trend of increasing stability from chlorides to bromides, provided that halogen polarizability or chemical bonding contribute appreciably to the binding of a complex. Supporting evidence is noted and further experiments are suggested. (author). 10 refs, 2 figs

  10. Chemical Stability of Chromium Carbide and Chromium Nitride Powders Compared with Chromium Metal in Synthetic Biological Solutions

    Tao Jiang; Inger Odnevall Wallinder; Gunilla Herting


    Chromium carbide (Cr-C) and chromium nitride (Cr-N) powders were compared with a chromium metal powder (Cr-metal) to evaluate their chemical stability in solution. All three powders were exposed in five different synthetic biological solutions of varying pH and chemical composition simulating selected human exposure conditions. Characterisation of the powders, using GI-XRD, revealed that the predominant bulk crystalline phases were Cr7C3 and Cr2N for Cr-C and Cr-N respectively. The outermost ...

  11. Low-chromium reduced-activation chromium-tungsten steels

    Klueh, R.L.; Alexander, D.J.; Maziasz, P.J. [Oak Ridge National Lab., TN (United States)


    Bainitic microstructures formed during continuous cooling can differ from classical upper and lower bainite formed during isothermal transformation. Two types of non-classical bainite were observed depending on the cooling rate: carbide-free acicular bainite at rapid cooling rates and granular bainite at slower cooling rates. The Charpy impact toughness of the acicular ferrite was found to be considerably better than for the granular bainite. It was postulated that alloying to improve the hardenability of the steel would promote the formation of acicular bainite, just as increasing the cooling rate does. To test this, chromium and tungsten were added to the 2 1/4Cr-2W and 2 1/4Cr-2WV steel compositions to increase their hardenability, and the microstructures and mechanical properties were examined.

  12. Bainitic chromium-tungsten steels with 3 pct chromium

    Previous work on 3Cr-1.5MoV (nominally Fe-3Cr-2.5Mo-0.25V-0.1C), 2.25Cr-2W (Fe-2.25Cr-2W-0.1C), and 2.25Cr-2WV (Fe-2.25Cr-2W-0.25V-0.1C) steels indicated that the impact toughness of these steels depended on the microstructure of the bainite formed during continuous cooling from the austenization temperature. Microstructures formed during continuous cooling can differ from classical upper and lower bainite formed during isothermal transformation. Two types of nonclassical microstructures were observed depending on the cooling rate: carbide-free acicular bainite at rapid cooling rates and granular bainite at slower cooling rates. The Charpy impact toughness of the acicular ferrite was considerably better than for the granular bainite. It was postulated that alloying to improve the hardenability of the steel would promote the formation of acicular bainite, just as increasing the cooling rate does. To test this, chromium and tungsten were added to the 2.25Cr-2W and 2.25Cr-2WV steel compositions to increase their hardenability. Charpy testing indicated that the new 3Cr-W and 3Cr-WV steels had improved impact toughness, as demonstrated by lower ductile-brittle transition temperatures and higher upper-shelf energies. This improvement occurred with less tempering than was necessary to achieve similar toughness for the 2.25Cr steels and for high-chromium (9 to 12 pct Cr) Cr-W and Cr-Mo steels

  13. Reproductive toxicological aspects of chromium in males

    To expand our present understanding of the effects of chromium on male fertility a number of studies were designed to achieve this through the use of chromium intoxicated experimental animals and through investigation of sexual hormones and sperm quality in welders. Also in view of the lack of an experimental model for effects of noxious substance on the epididymal spermatozoa the main objectives of the series of studies reviewed here were: A. To establish a model for evaluation of epididymal sperm count and motility in the rat. B. To investigate and compare the effects of tri- and hexavalent chromium on epididymal spermatozoa. Further to describe the effects of low-dose long-time exposure of rats to the most toxicological interesting chromium oxidative state - hexavalent chromium. C. By the use of autoradiography and γ-countinuing to expand the present knowledge on the distribution of chromium in the body with special reference to the male reproductive organs. D. To describe the effects of exposure to hexavalent chromium in welding fume on levels of sexual hormones and semen parameters in welders. (EG)

  14. Synthesis of Chromium (Ⅲ) 5-aminosalicylate

    LI Wei; HAO Er-jun; JIANG Yu-qin


    As we all known that diabetes is a chronic disease with major health consequences.Research has revealed that the occurrence of diabetes have great thing to do with the chromium deficient. Almost 40 years after the first report of glucose tolerance factor(GTF) [1], no conclusive evidence for an isolable ,biologically active form of chromium exited. Three materials have been proposed to be the biologically active form of chromium: "glucose tolerance factor", chromium Picolinate and low-molecular-weight chromium-binding substance (LWMCr) [2] . So there is potential for the design of new chromium drugs .5-Aminosalicylic acid (5-ASA) is identified as an active component in the therapy of inflammatory bowel disease (IBD) such as Crohn's disease and ulcerative colitis . The therapeutic action of 5-ASA is believed to be coupled to its ability to act as a free radical scavenger [3-4],acting locally on the inflamed colonic mucosa [5-7]. However, the clinical use of 5-ASA is limited, since orally administered 5-ASA is rapidly and completely absorbed from the upper gastrointestinal tract and therefore the local therapeutic effects of 5-ASA in the colon is hardly expected.In this paper, we report the synthesis of chromium(Ⅲ)5-aminosalicylate from 5-ASA and CrCl3. 6H2O.The synthesis route is as follow:The complex has been characterized by elemental analysis, IR spectra, X-ray powder diffractionand TG-DTA . They indicate that the structure is tris(5-ASA) Chromium . Experiments show that thecomplex has a good activity for supplement tiny dietary chromium, lowering blood glucose levels,lowering serum lipid levels and in creasing lean body mass .

  15. Chromium in leather footwear-risk assessment of chromium allergy and dermatitis

    Thyssen, Jacob P; Strandesen, Maria; Poulsen, Pia B;


    Background. Chromium-tanned leather footwear, which releases >3 ppm hexavalent Cr(VI), may pose a risk of sensitizing and eliciting allergic dermatitis. Objectives. To determine the content and potential release of chromium in leather footwear and to discuss the prevention of chromium contact...... allergy and dermatitis. Methods. Sixty pairs of leather shoes, sandals and boots (20 children's, 20 men's, and 20 women's) were purchased in Copenhagen and examined with X-ray fluorescence spectroscopy. Chromium was extracted according to the International Standard, ISO 17075. The detection level for Cr......(VI) was 3 ppm. Results. Chromium was identified in 95% of leather footwear products, the median content being 1.7% (range 0-3.3%). No association with store category or footwear category was found. A tendency for there to be a higher chromium content in footwear with high prices was shown (p(trend) = 0...

  16. Characteristics of chromium-allergic dermatitis patients prior to regulatory intervention for chromium in leather

    Bregnbak, David; Thyssen, Jacob P; Zachariae, Claus;


    BACKGROUND: Chromium-tanned leather articles currently constitute the most important cause of contact allergy to chromium in Denmark. A regulation on the content of hexavalent chromium in leather was adopted in November 2013 by the EU member states. OBJECTIVES: To characterize patients with...... chromium allergy and their disease, to serve as a baseline for future studies on the potential effect of the new regulation on chromium in leather. METHODS: A questionnaire case-control study was performed on 155 dermatitis patients with positive patch test reactions to potassium dichromate and a matched...... control group of 621 dermatitis patients. Comparisons were made by use of a χ(2) -test and the Mann-Whitney U-test. Logistic regression analyses were used to test for associations. RESULTS: Sixty-six per cent of chromium-allergic patients had a positive history of contact dermatitis caused by leather...

  17. Chromium intensification of a processed dental radiograph

    This study was undertaken to determine (1) the usefulness of chromium intensifier to improve the diagnostic quality of light radiograph; (2) the effect of chromium intensifier on density contrast; and (3) the effect of various chemical concentrations on density. The following results obtained: 1. CHROMIUM INTENSIFIER is useful for intensifying and improving the diagnostic quality of a light dental radiograph. 2. The degree of intensification can be controlled by varying bleaching time, repeating the processing, varying the proportions of the potassium bicarbonate and hydrochloric acid solutions. 3. The image produced is black and permanent. 4. The intensifier increases density and contrast

  18. Radioactive bromide partition test in early diagnosis of tuberculous meningitis

    Use of the radioactive bromide partition test in the early diagnosis of tuberculous meningitis is described briefly. Results of the (1) normal control group, (2) tuberculous menigitis group and (3) non-tuberculous lymphocytic meningitis are reported. Dose rates administered are specified. (K.B.)

  19. Depleting methyl bromide residues in soil by reaction with bases

    Despite generally being considered the most effective soil fumigant, methyl bromide (MeBr) use is being phased out because its emissions from soil can lead to stratospheric ozone depletion. However, a large amount is still currently used due to Critical Use Exemptions. As strategies for reducing the...

  20. Reactive films for mitigating methyl bromide emissions from fumigated soil

    Emissions of methyl bromide (MeBr) from agricultural fumigation can lead to depletion of the stratospheric ozone layer, and so its use is being phased out. However, as MeBr is still widely used under Critical Use Exemptions, strategies are still required to control such emissions. In this work, nove...

  1. Bromide interference with iodine metabolism in the rat

    Pavelka, Stanislav

    Hersonissos: ISTERH, 2007. E073-E073. [Conference International Society for Trace Element Research in Humans /8./. 21.10.2007-26.10.2007, Hersonisssos] R&D Projects: GA AV ČR(CZ) KJB401630701 Institutional research plan: CEZ:AV0Z50110509 Keywords : spr2 * bromide * iodine * metabolism Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  2. Bromide interference with iodine metabolism in the rat

    Pavelka, Stanislav


    Roč. 24, Suppl.1 (2008), S97-S98. ISSN 0742-2091. [Trace Elements in Diet , Nutrition and Health. 21.10.2008-26.10.2008, Hersonissos] Institutional research plan: CEZ:AV0Z50110509 Keywords : cpr1 * bromide * iodine * metabolism Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  3. Residues resulting from fumigation of food commodities with methyl bromide

    An investigation was undertaken to determine the nature and significance of residues remaining in methyl bromide-fumigated commodities using radiotracer techniques (14C-methyl bromide). Experiments with corn showed that the germ part of the kernel contained nearly half of the total 14C-residue remaining in the seed. Also preliminary tests with granny smith apples revealed that considerable residue may remain in seeds of treated apples with less in skin and the least in the fleshy pulp. In fumigated corn, fractionation revealed that radioactive residues were distributed throughout albumins, globulins, Zein 1, Zein 2 and glutelin with a large part in the aqueous extract (amino acids). Further investigation emphasized the characterization of volatile substances resulting from alkali treatment. It was found that methyl bromide readily methylated methionine and this constitutes a major site of methylation. A component of the volatile fraction was dimethyl sulfoxide, probably a product of oxidation of dimethyl sulphide. Work is in progress to determine whether methyl bromide will methylate purine and pyrimidine components. (author)

  4. Methyl bromide phase out could affect future reforestation efforts

    Methyl bromide has long been an integral component in producing healthy tree seedlings in forest nurseries of California, Idaho, Montana, Oregon and Washington. The fumigant was supposed to be completely phased out of use in the United States of America by 2005, but many forest nurseries continue to...

  5. Effects of exogenous bromide on the metabolism of iodine

    Pavelka, Stanislav

    Athens : University of Athens, 2003 - (Ermidou-Pollet, S.; Pollet, S.), s. 615-624 [Trace Elements in Human : New Perspectives /4./. Athens (GR), 09.10.2003-11.10.2003] Institutional research plan: CEZ:AV0Z5011922 Keywords : bromide * iodine * metabolism Subject RIV: ED - Physiology

  6. Palladium(0)-catalyzed methylenecyclopropanation of norbornenes with vinyl bromides.

    Mao, Jiangang; Bao, Weiliang


    Highly strained methylenecyclopropane derivatives have been achieved via a novel and efficient Pd(0)-catalyzed domino reaction. The formal [2 + 1] cycloaddition reaction of vinyl bromides to norbornenes involves a Heck-type coupling and a C(sp(2))-H bond activation. PMID:24784731

  7. Chromium (VI) adsorption on boehmite

    Granados-Correa, F. [Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027 Col., Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico)], E-mail:; Jimenez-Becerril, J. [Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027 Col., Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico)


    Boehmite was synthesized and characterized in order to study the adsorption behavior and the removal of Cr(VI) ions from aqueous solutions as a function of contact time, initial pH solution, amount of adsorbent and initial metal ion concentration, using batch technique. Adsorption data of Cr(VI) on the boehmite were analyzed according to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption models. Thermodynamic parameters for the adsorption system were determinated at 293, 303, 313 and 323 K temperatures. The kinetic values and thermodynamic parameters from the adsorption process show that the Cr(VI) ions adsorption on boehmite is an endothermic and spontaneous process. These results show that the boehmite could be considered as a potential adsorbent for chromium ions in aqueous solutions.

  8. Chromium – An essential mineral

    Merlin D Lindemann


    Full Text Available The status of chromium (Cr is not a new question. Cr is clearly an essential nutrient; this is a position that has been held for over three decades by individual scientists, groups of scientists, and governmental committees. The most uniform response across species with regard to Cr deficiency symptoms that are responsive to Cr supplementation are alterations in glucose metabolism with special reference to peripheral tissue sensitivity to insulin. Because the body’s ability to control blood glucose is critical to many life functions, and loss of ability to adequately control blood glucose can lead to many health debilitations, a consequence of Cr supplementation can be improved health and reproductive outcomes as well as improved survival rate or life span.

  9. Occupational asthma due to chromium.

    Leroyer, C; Dewitte, J D; Bassanets, A; Boutoux, M; Daniel, C; Clavier, J


    We describe a 28-year-old subject employed as a roofer in a construction company since the age of 19, who developed work-related symptoms of a cough, shortness of breath, wheezing, rhinitis and headaches. A description of a usual day at work suggested that the symptoms worsened while he was sawing corrugated fiber cement. Baseline spirometry was normal, and there was a mild bronchial hyperresponsiveness to carbachol. A skin patch test to chromium was negative. A specific inhalation challenge showed a boderline fall in forced expiratory volume in 1 s (FEV1) after exposure to fiber cement dust. Exposure to nebulization of potassium dichromate (K2Cr2O7), at 0.1 for 30 min, was followed by an immediate fall by 20% FEV1. Simultaneously, a significant increase in bronchial hyperresponsiveness was demonstrated. PMID:9782225

  10. Chromium isotope uptake in carbonates

    Rodler, Alexandra

    Chromium (Cr) is a redox sensitive element potentially capable of tracing fine-scale fluctuations of the oxygenation of Earth’s early surface environments and seawater. The Cr isotope composition of carbonates could perhaps be used as paleo-redox proxy to elucidate changes in the geological past....... Processes that potentially fractionate Cr isotopes, perhaps during deposition, burial and alteration need to be constrained.Previous studies have shown that Cr isotopes are fractionated during oxidative weathering on land, where heavy Cr isotopes are preferentially removed with Cr(VI) while residual soils...... retain an isotopically light Cr signature. Cr(VI) enriched in heavy Cr isotopes is then transported via river waters to the oceans and sequestered into marine sediments. Marine chemical sediments such asbanded iron formations and modern marine carbonates have proven useful in recording the Cr isotope...

  11. Comparative Biosorption Studies of Hexavalent Chromium Ion onto Raw and Modified Palm Branches

    Mona A. Shouman


    Full Text Available The waste of palm branches (PB was tested for its ability to remove chromium (VI from aqueous solution by batch and column experiments. Palm branches chemically modified with an oxidizing agent (sulphuric acid then coated with chitosan and surfactant (hexadecyl trimethyl ammonium bromide surfactant, HDTMA, respectively, were carried out to improve the removal performance of PB. The results of their Cr (VI removal performances are pH dependent. The adsorption data could be well interpreted by the Langmuir, Freundlich, and Flory-Huggins isotherm models. The maximum adsorption capacity obtained from the Langmuir model for the chitosan coated oxidized palm branches is 55 mg/mg. The adsorption process could be described by pseudo-second-order kinetic model. The intraparticle diffusion study revealed that film diffusion might be involved. The biosorbents were successfully regenerated using 1 M HCL solution.

  12. Simultaneous determination of chromium(III) and chromium(VI) in aqueous solutions by ion chromatography and chemiluminescence detection

    Gammelgaard, Bente; Jøns, O; Nielsen, B


    A method for the simultaneous determination of chromium(iii) and chromium(vi) in a flow system based on chemiluminescence was developed. A Dionex cation-exchange guard column was used to separate chromium(iii) from chromium(vi), and chromium(vi) was reduced by potassium sulfite, whereupon both sp....... The detection limit was 0.5 micrograms l-1 for both species. Data were in agreement with Zeeman-effect background corrected atomic absorption spectrometry measurements....

  13. Bromide interference with iodine metabolism: goitrogenic and whole-body effects of excessive inorganic bromide in the rat

    Pavelka, Stanislav

    Oxford: Academic Press, 2009 - (Preedy, V.; Burrow, G.; Watson, R.), s. 587-595 ISBN 978-0-12-374135-6 Grant ostatní: EC(XE) LSHG-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * iodine * metabolism Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition


    Suyuan Yu


    Cr2O3 is considered as the dominant incineration product during the combustion disposal of chromium waste. A hydrogen/air diffusion flame was employed to simulate the industrial process of incineration. Cr2O3 aerosols were generated inside the flame by the gas phase reaction of chromium and oxygen. Chromium came from the rapid decomposition of chromium hexacarbonyl (Cr(CO)6) at room temperature and was carried into the combustion chamber by hydrogen. Aerosol and clusters can then be easily formed in the flame by nucleation and coagulation. A two dimensional Discrete-Sectional Model (DSM) was adopted to calculate the Cr2O3 aerosol behavior. The experimental measurement method was Dynamic Light Scattering. The numerically predicted results agreed well with those of the experimental measurement. Both results show that the Cr2O3 aerosol size reached about 70 nanometers at the flame top.

  15. Potentiometry: A Chromium (III) -- EDTA Complex

    Hoppe, J. I.; Howell, P. J.


    Describes an experiment that involves the preparation of a chromium (III)-EDTA compound, a study of its infrared spectrum, and the potentiometric determination of two successive acid dissociation constants. (Author/GS)

  16. Association of defects in lead chloride and lead bromide: Ionic conductivity and dielectric loss measurements

    Brom, W.E. van den; Schoonman, J.; Wit, J.H.W. de


    The ionic conductivity data of pure and doped lead bromide without associated defects are used in order to explain the anomalous conductivity behaviour of copper (I) bromide and lead oxide-doped lead-bromide crystals. In these crystals precipitated dopant and associated defects are present. The asso

  17. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.


    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  18. Detection of lipopolysaccharides by ethidium bromide staining after sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

    Kido, N; Ohta, M; Kato, N


    A rapid and easy method for staining lipopolysaccharides with ethidium bromide is described. Lipopolysaccharides could be visualized by ethidium bromide with almost the same sensitivity as found with the silver-staining method in less than 30 min. The ethidium bromide-staining method was particularly suitable for staining lipopolysaccharides possessing acidic O-specific polysaccharides, which were poorly visualized by silver staining.

  19. A comparison of the effect of intranasal desmopressin and intramuscular hyoscine N-butyl bromide combination with intramuscular hyoscine N-butyl bromide alone in acute renal colic

    Abdol-Reza Kheirollahi; Mohammad Tehrani; Mohammad Bashashati


    Background: Patients with acute renal colic usually require immediate diagnosis and treatment. In this clinical trial analgesic effect of hyoscine N-butyl bromide and desmopressin combination in comparison with hyoscine N-butyl bromide alone in patients with acute renal colic induced by urinary stones was assessed. Methods: The study included 114 patients randomly allocated in two groups (A and B). Patients in group A received 20 mg intramuscular hyoscine N-butyl bromide at admission tim...

  20. Bioremediation of chromium solutions and chromium containing wastewaters.

    Malaviya, Piyush; Singh, Asha


    Cr(VI) represents a serious threat to human health, living resources and ecological system as it is persistent, carcinogenic and toxic, whereas, Cr(III), another stable oxidation state of Cr, is less toxic and can be readily precipitated out of solution. The conventional methods of Cr(VI) removal from wastewaters comprise of chemical reduction followed by chemical precipitation. However, these methods utilize large amounts of chemicals and generate toxic sludge. This necessitates the need for devising an eco-technological strategy that would use the untapped potential of the biological world for remediation of Cr(VI) containing wastewaters. Among several viable approaches, biotransformation of Cr(VI) to relatively non-toxic Cr(III) by chromium resistant bacteria offers an economical- and environment-friendly option for its detoxification. Various studies on use of Cr(VI) tolerant viable bacterial isolates for treatment of Cr(VI) containing solutions and wastewater have been reported. Therefore, a detailed account of mechanisms and processes involved in bioreduction of Cr(VI) from solutions and wastewaters by bacterial isolates are the focus of this review article in addition to a discussion on toxicity of Cr(VI) on bacterial strains and various factors affecting Cr(VI) bioreduction. PMID:25358056

  1. Diminishing Chromium Use on Combined Chromium-Gambier Tanning Process Upon the Characteristics of Tanned Leather

    A. Kasim


    Full Text Available The research was aimed to investigate the influence of minimizing chromium use on combined chromium-gambier process upon the characteristics of tanned leather. At the first stage of tanning process, chromium was used and in the second stage it was replaced by gambier. The raw material used was dried saline-preserved goat skin. The treatments applied on the tanning process were the different concentrations of chromium ranging from the highest level of 6% to the lowest level of 1% which was then re-tanned by using 8% concentration of gambier. The examination parameters included chemical and physical properties as well as visual investigation on the tanned leather in accordance with SNI-06-0463-1989-A. The result showed that the tanning process by using 2% chromium in the first step and 8% gambier in the second step was a treatment combination producing tanned leather that met the standard. The examination on tanned leather resulted from such treatment showed 56.33% rawhide, 17.45% of bound tannin, 31.22% of tanning level, tensile strength 386.30 kg/cm2, flexibility 31.91%, leather width 1.3 mm, density 0.75 g/cm3, the leather was quite elastic with light brownish color. In conclusion, minimizing the use of chromium in the combined tanning process of chromium and gambier can be implemented to the lowest of 2% chromium concentration and 8% gambier in the first and second step, respectively.

  2. Lateral stress evolution in chromium sulfide cermets with varying excess chromium

    Petel, O. E.; Appleby-Thomas, G. J.; Wood, D. C.; Capozzi, A.; Nabavi, A.; Goroshin, S.; Frost, D. L.; Hazell, P. J.


    The shock response of chromium sulfide-chromium, a cermet of potential interest as a matrix material for ballistic applications, has been investigated at two molar ratios. Using a combustion synthesis technique allowed for control of the molar ratio of the material, which was investigated under near-stoichiometric (cermet) and excess chromium (interpenetrating composite) conditions, representing chromium:sulfur molar ratios of 1.15:1 and 4:1, respectively. The compacts were investigated via the plate-impact technique, which allowed the material to be loaded under a one-dimensional state of strain. Embedded manganin stress gauges were employed to monitor the temporal evolution of longitudinal and lateral components of stress in both materials. Comparison of these two components has allowed assessment of the variation of material shear strength both with impact pressure/strain-rate and time for the two molar ratio conditions. The two materials exhibited identical material strength despite variations in their excess chromium contents.

  3. [2,6-Bis(dimethylaminomethylphenyl]selenium bromide monohydrate

    Richard A. Varga


    Full Text Available In the title hydrated molecular salt, C12H19N2Se+·Br−·H2O, the two independent bromide anions lie on a twofold rotation axis. Strong intramolecular N→Se interactions [2.185 (3 and 2.181 (3 Å] are established by both N atoms of the organic group in the cation, in trans positions to each other, with an N—Se—N angle of 161.6 (1°, resulting in a T-shaped (C,N,N′Se core. In the crystal, dimeric associations are formed by Br...Se [3.662 (2 Å] and Br...H interactions [2.56 (6 and 2.63 (7 Å] involving two bromide anions, two cations and two water molecules.

  4. Use of 82Br and 131I radionuclides in studies of goitrogenic effects of exogenous bromide

    The interference of excessive bromide intake with iodine metabolism in the rat was studied using 82Br and 131I radionuclides. Mainly lactating rat dams and their pups were used, in addition to adult male rats, in the present studies. Particularly, the influence of high bromide intake in lactating rat dams on the transfer of iodine and bromide to suckling young through breast milk was evaluated. The induction of hypothyroid status in the pups by high bromide intake in the mothers was proved unambiguously. Excessive bromide in lactating rat dams caused a marked decrease in plasma levels of thyroid hormones both, in the mothers and in their sucklings. The effects of an enhanced bromide intake on the thyroid function in relation to iodine status in the animals were also followed. Marked goitrogenic and thyrotoxic effects of excessive bromide in adult rats were significantly enhanced under the conditions of simultaneous iodine deficiency in the experimental animals. (author)

  5. Very long terahertz free induction decay in gaseous hydrogen bromide

    Free induction decay radiation was observed in low pressure hydrogen bromide that continued for more than 180 ns after excitation by a terahertz pulse from a free electron laser. The signal was measured in real time using an ultrafast Schottky diode detector. Such a signal corresponds in frequency domain spectral resolution to about 10 MHz, which allows for resolution of the isotopic and quadrupole structure of the absorption line. (letter)

  6. Thyrotoxic effects of exogenous bromide in the rat

    Pavelka, Stanislav

    Bratislava: Slovak University of Technology, 2008 - (Manová, A.; Čacho, F.), s. 173-174 ISSN 1335-3160. [Priemyselná toxikológia 08 /28./. Tatranská Štrba (SK), 18.06.2008-20.06.2008] Grant ostatní: GA AV ČR(CZ) KJB401630701; MYORES(XE) 511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : thyroid gland * bromide * rat Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  7. High-speed Laser Micromachining with Copper Bromide Laser

    Balchev, I I; Minkovski, N I; Sabotinov, N V; Balchev, Ivaylo I.; Kostadinov, Ivan K.; Minkovski, Nikolai I.; Sabotinov, Nikola V.


    The application of the copper bromide (CuBr) laser as an attractive tool in the micro-machining of different materials has been demonstrated. High-quality drilling by trepanning and precision cutting was established on several materials with a negligible heat-affected zone (HAZ). That good performance was a result of the combination of high power visible radiation, short pulses, and close to the diffraction-limited laser beam quality with high-speed galvo scanner beam steering.

  8. Criticality in aqueous solutions of 3-methylpyridine and sodium bromide.

    Kostko, A F; Anisimov, M A; Sengers, J V


    We address a controversial issue regarding the nature of critical behavior in ternary electrolyte solutions of water, 3-methylpyridine, and sodium bromide. Earlier light-scattering studies showed an anomalous critical behavior in this system that was attributed to the formation of a microheterogeneous phase associated with ion-molecule clustering [M.A. Anisimov, J. Jacob, A. Kumar, V.A. Agayan, and J. V. Sengers, Phys. Rev. Lett. 85, 2336 (2000)


    Hromadová, Magdaléna; Pospíšil, Lubomír; Sokolová, Romana; Kolivoška, Viliam


    Roč. 76, č. 12 (2011), s. 1895-1908. ISSN 0010-0765 R&D Projects: GA AV ČR IAA400400802; GA ČR GA203/08/1157; GA ČR GA203/09/0705; GA MŠk(CZ) MEB041006 Institutional research plan: CEZ:AV0Z40400503 Keywords : spectroelectrochemistry * dodecylpyridinium bromide * mechanistic studies Subject RIV: CG - Electrochemistry Impact factor: 1.283, year: 2011

  10. 4-Hydroxy-1,2,6-trimethylpyridinium bromide monohydrate

    T. Seethalakshmi


    Full Text Available The title salt, C8H12NO+·Br−·H2O, is isomorphous with the chloride analogue [Seethalakshmi et al. (2013. Acta Cryst. E69, o835–o836]. In the solid state, the cations, anions and water molecules are interlinked by a network of O—H...O, O—H...Br and C—H...Br interactions. The water molecule makes two O—H...Br hydrogen bonds, generating [010] zigzag chains of alternating water molecules and bromide anions. The cation is involved in two intermolecular C—H...Cl interactions in the chloride salt, whereas three intermolecular C—H...Br interactions are observed in the title bromide salt. This additional intermolecular C—H...Br interaction links the adjacent water and bromide zigzag chains via cationic molecules. In addition, weak π–π stacking interactions are observed between pyridinium rings [centroid–centroid distance = 3.5664 (13 Å].

  11. Structural, vibrational and theoretical studies of L-histidine bromide

    Ahmed, A. Ben; Feki, H.; Abid, Y.; Boughzala, H.; Mlayah, A.


    This paper presents the results of our calculations of the geometric parameters, vibrational spectra and hyperpolarizability of a non linear optical material, L-histidine bromide. Due to the lack of sufficiently precise information on the geometric structure available in literature, theoretical calculations were preceded by re-determination of the crystal X-ray structure. Single crystals of L-histidine bromide have been grown by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in the non-Centro symmetric space group P2 12 12 1 of the orthorhombic system. Raman spectra have been recorded in the range [200-3500 cm -1]. All observed vibrational bands have been discussed and assigned to normal mode or to combinations and overtones on the basis of our calculations. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP and BLYP) show good agreement with the experimental data. Comparison between the measured and the calculated vibrational frequencies indicate that B3LYP is superior to the scaled HF approach for molecular vibrational problems. To investigate microscopic second order non linear optical properties of L-histidine bromide, the electric dipole μ, the polarizability α and the hyperpolarizability β were computed using DFT//B3LYP/6-31G(d) method. According to our calculations, the title compound exhibits non-zero β value revealing microscopic second order NLO behaviour.

  12. L-Tryptophan L-tryptophanium bromide: Anhydrous and monohydrate

    Ghazaryan, V. V.; Giester, G.; Fleck, M.; Petrosyan, A. M.


    L-Tryptophan L-tryptophanium bromide (I) and L-tryptophan L-tryptophanium bromide monohydrate (II) are new salts with (A⋯A+) type dimeric cation. The salt (I) crystallizes in the monoclinic system (space group P21, Z = 2) and is isostructural with respective chloride (V.V. Ghazaryan et al., Spectrochim. Acta A 136(2015) 743-750), while the salt (II) was obtained previously (T. Takigawa et al., Bull. Chem. Soc. Jap. 39(1966) 2369-2378) and described as hemyhydrate without structure determination. The salt (II) crystallizes in orthorhombic system (space group P212121, Z = 4). The dimeric cations in (I) and (II) are formed by O-H⋯O hydrogen bonds with the O⋯O distances equal to 2.538(3) Å and 2.481(3) Å respectively. The infrared and Raman spectra of the crystals are studied and compared with the spectra of L-tryptophan L-tryptophanium chloride and L-tryptophanium bromide.

  13. Palladium-catalyzed thiocarbonylation of aryl, vinyl, and benzyl bromides.

    Burhardt, Mia N; Ahlburg, Andreas; Skrydstrup, Troels


    A catalytic protocol for synthesis of thioesters from aryl, vinyl, and benzyl bromides as well as benzyl chlorides was developed using only stoichiometric amounts of carbon monoxide, produced from a solid CO precursor inside a two-chamber system. As a catalytic system, the combination of bis(benzonitrile) palladium(II) chloride and Xantphos furnished the highest yields of the desired compounds, along with the weak base, NaOAc, in anisole at 120 °C. The choice of catalytic system as well as solvent turned out to be important in order to ensure a high chemoselectivity in the reaction. Both electron-rich and electron-deficient aryl bromides worked well in this reaction. Addition of 1 equiv of sodium iodide to the reaction improved the chemoselectivity with the electron-deficient aryl bromides. The thiol scope included both aryl and alkyl thiols, including 2-mercaptobenzophenones, whereby a thiocarbonylation followed by a subsequent McMurry coupling yielded differently substituted benzothiophenes. It was demonstrated that the methodology could be applied for (13)C introduction into the thiophene ring. PMID:24919457

  14. High bromide intake in the lactating rat significantly influences transfer of iodine and bromide via mother's milk

    Pavelka, Stanislav

    Brno : Masarykova univerzita, 2007. s. 13-14. ISBN 80-120-3942-6. [Pracovní setkání biochemiků a molekulárních biologů /10./. 08.02.2006-09.02.2006, Brno] Institutional research plan: CEZ:AV0Z50110509 Keywords : spr2 * bromide * iodine * rat Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  15. High bromide intake in the lactating rat significantly influences transfer of iodine and bromide via mother's milk

    Pavelka, Stanislav

    Brno : Masarykova univerzita v Brně, 2006 - (Wimmerová, M.; Beneš, P.). s. 13-14 ISBN 80-210-3942-6. [Pracovní setkání biochemiků a molekulárních biologů /10./. 08.02.2006-09.02.2006, Brno] Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * iodine * mother's milk Subject RIV: ED - Physiology

  16. The enriched chromium neutrino source for GALLEX

    The preparation and study of an intense source of neutrinos in the form of neutron irradiated materials which are enriched in Cr-50 for use in the GALLEX solar neutrino experiment are discussed. Chromyl fluoride gas is enriched in the Cr-50 isotope by gas centrifugation and subsequently converted to a very stable form of chromium oxide. The results of neutron activation analyses of such chromium samples indicate low levels of any long-lived activities, but show that short-lived activities, in particular Na-24, may be of concern. These results show that irradiating chromium oxide enriched in Cr-50 is preferable to irradiating either natural chromium or argon gas as a means of producing a neutrino source to calibrate the GALLEX detector. These results of the impurity level analysis of the enriched chromyl fluoride gas and its conversion to the oxide are also of interest to work in progress by other members of the Collaboration investigating an alternative conversion of the enriched gas to chromium metal. 35 refs., 12 figs., 5 tabs

  17. Serum chromium levels in gestational diabetes mellitus

    P G Sundararaman


    Full Text Available Objective: To measure serum chromium level in women with gestational diabetes mellitus (GDM from Chennai, South India. Materials and Methods: Thirty women with gestational diabetes, 60 age matched controls. Inclusion criteria: Gestational age 22-28 weeks, age group 20-35 years. Exclusion Criteria: Gestational age beyond 28 weeks, malnutrition or presence of infection. Serum chromium was measured using inductive couple plasma emission spectrometer. Results: Serum chromium levels of women with GDM, 1.59+/-0.02 ng/ml (range: 0.16-4.0 ng/ml were lower than in controls (4.58+/-0.62 ng/ml; range 0.82-5.33 ng/ml (P < 0.001. However, there were no significant differences among cases and controls when subdivided by parity. Conclusions: Women with GDM from a South Indian city had lower levels of serum chromium compared to pregnant women without GDM. Studies may be done whether chromium supplementation is useful in this group of women.

  18. Occupational exposure to chromium(VI compounds

    Jolanta Skowroń


    Full Text Available This article discusses the effect of chromium(VI (Cr(VI on human health under conditions of acute and chronic exposure in the workplace. Chromium(VI compounds as carcinogens and/or mutagens pose a direct danger to people exposed to them. If carcinogens cannot be eliminated from the work and living environments, their exposure should be reduced to a minimum. In the European Union the proposed binding occupational exposure limit value (BOELV for chromium(VI of 0.025 mg/m³ is still associated with high cancer risk. Based on the Scientific Commitee of Occupational Exposure Limits (SCOEL document chromium(VI concentrations at 0.025 mg/m³ increases the risk of lung cancer in 2–14 cases per 1000 exposed workers. Exposure to chromium(VI compounds expressed in Cr(VI of 0.01 mg Cr(VI/m3 is responsible for the increased number of lung cancer cases in 1–6 per 1000 people employed in this condition for the whole period of professional activity. Med Pr 2015;66(3:407–427

  19. [Occupational exposure to chromium(VI) compounds].

    Skowroń, Jolanta; Konieczko, Katarzyna


    This article discusses the effect of chromium(VI) (Cr(VI)) on human health under conditions of acute and chronic exposure in the workplace. Chromium(VI) compounds as carcinogens and/or mutagens pose a direct danger to people exposed to them. If carcinogens cannot be eliminated from the work and living environments, their exposure should be reduced to a minimum. In the European Union the proposed binding occupational exposure limit value (BOELV) for chromium(VI) of 0.025 mg/m³ is still associated with high cancer risk. Based on the Scientific Commitee of Occupational Exposure Limits (SCOEL) document chromium(VI) concentrations at 0.025 mg/m³ increases the risk of lung cancer in 2-14 cases per 1000 exposed workers. Exposure to chromium(VI) compounds expressed in Cr(VI) of 0.01 mg Cr(VI)/m3; is responsible for the increased number of lung cancer cases in 1-6 per 1000 people employed in this condition for the whole period of professional activity. PMID:26325053

  20. Solid miscibility of common-anion lithium and sodium halides. Experimental determination of the region of demixing in lithium bromide + sodium bromide

    Oonk, H.A.J.; Wijk, H.J. van; Doornhof, D.


    The region of demixing of solid lithium bromide + sodium bromide mixtures has been measured by X-ray diffraction. The critical temperature of mixing corresponding to a thermodynamic fit of the experimental data is 513 K. Estimates are given of the regions of demixing in solid lithium chloride + sodi

  1. Flashlamp-pumped lasing of chromium-doped GSG garnet

    The implications for the practical use of chromium:GSGG in lamp-pumped tunable lasers are discussed in this paper. The authors report here some major improvements in the performance of the flashlamp-pumped chromium:GSGG laser

  2. Surface Chemistry and Spectroscopy of Chromium in Inorganic Oxides

    Weckhuysen, B. M.; Wachs, I.E.; Schoonheydt, R. A.


    Focuses on the surface chemistry and spectroscopy of chromium in inorganic oxides. Characterization of the molecular structures of chromium; Mechanics of hydrogenation-dehydrogenation reactions; Mobility and reactivity on oxidic surfaces.

  3. Studies of Some Novel Chromium Pyridine Dicarboxylate Complexes

    Chauhan Jayprakash S; Patel Rameshchandra P; Pandya Ajit V


    Chromium pyridine di-carboxylate complexes are synthesized from Chromium (III) with pyridine 2, 6- dicarboxylic acid, pyridine 2, 3 and 2, 5- dicarboxylic acids. Chromium forms colored complexes. Chromium (III) forms a violate complex with pyridine 2, 6- dicarboxylic acid and purple violate complex with pyridine 2, 3 and 2, 5- dicarboxylic acids. The job’s method indicates metal ligand ratio to be 1:2. The interpretation of UV-VIS spectra indicates octahedral geometry and IR spectra give clue...

  4. Determination of chromium combined with DNA, RNA and proteins in chromium-rich brewer's yeast by NAA

    The content of chromium in the DNA, RNA and protein fractions separated from chromium-rich and normal brewer's yeast was determined by neutron activation analysis (NAA). Our results show that the extracted relative amounts and concentrations of DNA, RNA and proteins have no significant difference for two types of yeast, but the chromium content in DNA, RNA and proteins fractions extracted from the chromium-rich yeast are substantially higher than those from the normal. In addition, the concentration of chromium in DNA is much higher than that in RNA and proteins. It is evident that the inorganic chromium compounds can enter the yeast cell during the yeast cultivation in the chromium-containing culture medium and are converted into organic chromium species, which are combined with DNA, RNA and proteins. (author)

  5. Chromium allergy and dermatitis: prevalence and main findings

    Bregnbak, David; Johansen, Jeanne D.; Jellesen, Morten Stendahl;


    The history of chromium as an allergen goes back more than a century, and includesan interventional success with national legislation that led to significant changes inthe epidemiology of chromium allergy in construction workers. The 2015 EU Leather Regulation once again put a focus on chromium...

  6. 21 CFR 73.1326 - Chromium hydroxide green.


    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide...

  7. 21 CFR 73.2326 - Chromium hydroxide green.


    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium hydroxide green. 73.2326 Section 73.2326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and specifications.The color additive chromium hydroxide green shall conform in identity and specifications to...

  8. Thermodynamic properties of chromium bearing slags and minerals. A review

    Xiao Yanping; Holappa, L.


    In this report, the thermodynamic properties of chromium bearing slags and minerals were reviewed based on the available information in the literature. It includes the analysing methods for oxidation state of chromium in slags, oxidation state of chromium and activities of chromium oxides in slags and minerals. The phase diagrams of chromium oxide systems and chromium distributions between slag and metal phases are also covered ill this review. Concerning the analysing methods, it was found that most of the available approaches are limited to iron free slag systems and the sample preparation is very sensitive to the analysing results. In silicate slags under reducing atmosphere, divalent and trivalent chromium co-exist in the slags. It is agreed that the fraction of divalent chromium to total chromium increases with higher temperature, lower slag basicity and oxygen potential. For the slags under oxidising atmosphere, trivalent, pentavalent and hexavalent states were reported to be stable. The activities of CrO and CrO{sub 1.5} were concluded to have positive deviation from ideal solution. Slag basicity has a positive effect and temperature has a negative effect on the activities of chromium oxides. The phase diagrams of the Cr-O, binary, and ternary chromium containing oxide systems have been examined systematically. The analysis shows that the data on the quaternary and quinary systems are insufficient, and require further investigation. The most important features of the chromium containing silicate slags are the large miscibility gaps and the stability of the chromite spinel. (orig.) (76 refs.)

  9. 21 CFR 73.1015 - Chromium-cobalt-aluminum oxide.


    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium-cobalt-aluminum oxide. 73.1015 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1015 Chromium-cobalt-aluminum oxide. (a) Identity. The color additive chromium-cobalt-aluminum oxide is a blue-green pigment obtained by calcining...

  10. Hexavalent and trivalent chromium in leather: What should be done?

    Moretto, Angelo


    Trivalent chromium compounds are used for leather tanning, and chromium may be released during use of leather goods. In certain instances, small amounts of hexavalent chromium can be formed and released. Both trivalent and hexavalent chromium can elicit allergic skin reaction in chromium sensitised subjects, the latter being significantly more potent. Induction of sensitisation only occurs after exposure to hexavalent chromium. A minority of subjects are sensitised to chromium, and in a fraction of these subjects allergic skin reaction have been described after wearing leather shoes or, less frequently, other leather goods. The evidence that in all these cases the reaction is related to hexavalent chromium is not always strong. The content of hexavalent chromium in leather is regulated in European Union, but rate of release rather than content is relevant for allergic skin reaction. The role of trivalent chromium appear much less relevant if at all. Modern tanning procedure do not pose significant risk due to either hexavalent or trivalent chromium. Dismissing bad quality and worn-off leather goods is relevant in reducing or eliminating the skin reaction. It should also be pointed out that shoe components or substances other than chromium in leather may cause allergic/irritative skin reactions. PMID:26361854


    Toxicity studies regarding trivalent chromium have often been completed under conditions that are not designed to reflect conditions that would be encountered under normal physiological conditions. We have shown that the incorporation of chromium into tissues of rats from chromium chloride and chro...

  12. Strategies for chromium bioremediation of tannery effluent.

    Garg, Satyendra Kumar; Tripathi, Manikant; Srinath, Thiruneelakantan


    Bioremediation offers the possibility of using living organisms (bacteria, fungi, algae,or plants), but primarily microorganisms, to degrade or remove environmental contaminants, and transform them into nontoxic or less-toxic forms. The major advantages of bioremediation over conventional physicochemical and biological treatment methods include low cost, good efficiency, minimization of chemicals, reduced quantity of secondary sludge, regeneration of cell biomass, and the possibility of recover-ing pollutant metals. Leather industries, which extensively employ chromium compounds in the tanning process, discharge spent-chromium-laden effluent into nearby water bodies. Worldwide, chromium is known to be one of the most common inorganic contaminants of groundwater at pollutant hazardous sites. Hexavalent chromium poses a health risk to all forms of life. Bioremediation of chromium extant in tannery waste involves different strategies that include biosorption, bioaccumulation,bioreduction, and immobilization of biomaterial(s). Biosorption is a nondirected physiochemical interaction that occurs between metal species and the cellular components of biological species. It is metabolism-dependent when living biomass is employed, and metabolism-independent in dead cell biomass. Dead cell biomass is much more effective than living cell biomass at biosorping heavy metals, including chromium. Bioaccumulation is a metabolically active process in living organisms that works through adsorption, intracellular accumulation, and bioprecipitation mechanisms. In bioreduction processes, microorganisms alter the oxidation/reduction state of toxic metals through direct or indirect biological and chemical process(es).Bioreduction of Cr6+ to Cr3+ not only decreases the chromium toxicity to living organisms, but also helps precipitate chromium at a neutral pH for further physical removal,thus offering promise as a bioremediation strategy. However, biosorption, bioaccumulation, and

  13. Collisional properties of trapped cold chromium atoms

    Pavlovich, Z; Côté, R; Sadeghpour, H R; Pavlovic, Zoran; Roos, Bjoern O.; Côté, Robin


    We report on calculations of the elastic cross section and thermalization rate for collision between two maximally spin-polarized chromium atoms in the cold and ultracold regimes, relevant to buffer-gas and magneto-optical cooling of chromium atoms. We calculate ab initio potential energy curves for Cr2 and the van der Waals coefficient C6, and construct interaction potentials between two colliding Cr atoms. We explore the effect of shape resonances on elastic cross section, and find that they dramatically affect the thermalization rate. Our calculated value for the s-wave scattering length is compared in magnitude with a recent measurement at ultracold temperatures.

  14. Influence of nitrogen on the structure and properties of chromium, chromium-molybdenum and chromium-manganese steels

    Phase transformations, precipitation processes and properties of the chromium, chromium-molybdenum and chromium-manganese steels with a high content of nitrogen as the dependence on thermal treatment were investigated. In case of Fe-0.08C-18Cr-18Mn-N and Fe-0.08C-18Cr-18Mn-2Mo-N steels the samples in the state after solution at temperature 1050oC and 1150oC and 1250oC and after subsequent annealing in 600oC and 800oC were investigated. heat treatment of the Fe-0.5C-10Cr-N and Fe-0.5C-10Cr-1Mo-N steels included austenitizment from 1000oC with air cooling and hardening from 1000oC with oil cooling and tempering in 650oC and 750oC in two hours with cooling in the air. These investigations show that the influence of nitrogen as an alloy element on the phase transformations, precipitation processes, mechanical and corrosion properties is connected with the presence of molybdenum and chromium in the steel. Nitrogen with these elements creates complex ions with the coordinate number 6. This statement is formed on the base of both calculations and investigation results. (author)

  15. Automated determination of bromide in waters by ion chromatography with an amperometric detector

    Pyen, G.S.; Erdmann, D.E.


    An automated ion chromatograph, including a program controller, an automatic sampler, an integrator, and an amperometric detector, was used to develop a procedure for the determination of bromide in rain water and many ground waters. Approximately 10 min is required to obtain a chromatogram. The detection limit for bromide is 0.01 mg l-1 and the relative standard deivation is <5% for bromide concentrations between 0.05 and 0.5 mg l-1. Chloride interferes if the chloride-to-bromide ratio is greater than 1 000:1 for a range of 0.01-0.1 mg l-1 bromide; similarly, chloride interferes in the 0.1-1.0 mg l-1 range if the ratio is greater than 5 000:1. In the latter case, a maximum of 2 000 mg l-1 of chloride can be tolerated. Recoveries of known concentrations of bromide added to several samples, ranged from 97 to 110%. ?? 1983.

  16. A study of bromide in the Mandovi-Zuari river system of Goa

    de Souza, Francisca P.; Dalal, V. N. Kamat


    Bromide was the subject of detailed investigation in the Mandovi-Zuari river system and information was compiled on its spatial and temporal distribution. A simple mixture relation of Carpenter et al. was applied and seawater percentage and bromide concentrations were computed. The variation of bromide with chlorinity was linear indicating the purely conservative character of bromide and its seawater origin. Seawater ranged between 1 and 3% in monsoon, 76 and 91% in post-monsoon and 92 and 97% in pre-monsoon in the Mandovi-Zuari river system. As the bromide concentration varied linearly with chlorinity both longitudinally and depthwise, it followed that bromide exhibited a simple distribution pattern established by conservative mixing.

  17. Enzyme activities in agricultural soils fumigated with methyl bromide alternatives

    Klose, Susanne; Ajwa, H A


    Pre-plant fumigation of agricultural soils with a combination of methyl bromide (MeBr) and chloropicrin (CP) to control nematodes, soil-borne pathogens and weeds has been a common practice in strawberry (Fragaria X ananassa Duchesne) production since the 1960s. MeBr will be phased out by 2005, but little is known about the impacts of alternative fumigants on soil microbial processes. We investigated the response of microbial biomass and enzyme activities in soils fumigated over two years with...

  18. On the complexing of certain transition metal bromides with trimecaine

    Synthesis and IR spectroscopy of the structure of cadmium bromide coordination compounds and certain other elements with trimecaine (diethylamino-2,4-6-trymethylacetanilidine, L) are carried out. Complexes of the CdLBr2(1) and Cd(LH)2Br4(2) composition are prepared, this molecular structure is established. In complex 1 cadmium atom is shown to be coordinately related to the nitrogen atom of the ternary aminogroup; in complex 2 the bond between the CdBr42- anion and ternary nitrogen atom of the ligand is of the ionic character

  19. Interaction between gaseous ozone and crystalline potassium bromide

    Levanov, A. V.; Maksimov, I. B.; Isaikina, O. Ya.; Antipenko, E. E.; Lunin, V. V.


    The formation of nonvolatile products of the oxidation of a bromide ion during the interaction between gaseous ozone and powdered crystalline KBr is studied. It is found that potassium bromate KBrO3 is the main product of the reaction. The influence of major experimental factors (the duration of ozonation, the concentration of ozone, the humidity of the initial gas, and the temperature) on the rate of formation of bromate is studied. The effective constants of the formation of bromate during the interaction between O3 and Br- in a heterogeneous gas-solid body system and in a homogeneous aqueous solution are compared.

  20. Suicide by intravenous injection of rocuronium-bromide: Case report

    Nikolić Slobodan


    Full Text Available Suicides by intravenous injection of an overdose of medicaments are uncommon. In this paper, we present the case of a suicide by rocuronium-bromide injection in combination with an oral overdose of metoprolol. Unfortunately, in Belgrade, there is no toxicological laboratory capable of detecting rocuronium. The interpretation of autopsy and toxicological data in this case was made difficult due to the extreme putrefaction of the body of the deceased. So, by forensic investigation, the case was solved indirectly, through circumstantial evidence: an empty ampoule of rocuronium found near the body, as well as a plastic syringe and cloth-bandage found in the left hand of the deceased.

  1. Bacterial Oxidation of Methyl Bromide in Fumigated Agricultural Soils

    Miller, L. G.; Connell, T. L.; Guidetti, J. R.; Oremland, R. S.


    The oxidation of [(sup14)C]methyl bromide ([(sup14)C]MeBr) to (sup14)CO(inf2) was measured in field experiments with soils collected from two strawberry plots fumigated with mixtures of MeBr and chloropicrin (CCl(inf3)NO(inf2)). Although these fumigants are considered potent biocides, we found that the highest rates of MeBr oxidation occurred 1 to 2 days after injection when the fields were tarped, rather than before or several days after injection. No oxidation of MeBr occurred in heat-kille...

  2. Methyl bromide: Ocean sources, ocean sinks, and climate sensitivity

    A. D. Anbar; Yung, Y. L.; Chavez, F.P.


    The oceans play an important role in the geochemical cycle of methyl bromide (CH_3Br), the major carrier of O_3-destroying bromine to the stratosphere. The quantity of CH_3Br produced annually in seawater is comparable to the amount entering the atmosphere each year from natural and anthropogenic sources. The production mechanism is unknown but may be biological. Most of this CH_3Br is consumed in situ by hydrolysis or reaction with chloride. The size of the fraction which escapes to the atmo...

  3. Electrodeposition of black chromium thin films from trivalent chromium-ionic liquid solution

    Eugénio, S.; Vilar, Rui; C. M. Rangel; Baskaran, I.


    In the present study, black chromium thin films were electrodeposited from a solution of 1-butyl-3- methylimidazolium tetrafluoroborate ([BMIm][BF4] ionic liquid containing trivalent chromium (Cr(III)). Homogeneous and well adherent coatings have been obtained on nickel, copper and stainless steel substrates. The nucleation and growth of the films were investigated by cyclic voltammetry and current-density/time transient techniques. SEM/EDS, XPS and XRD were used to study the morphology, chem...

  4. Reduction of Hexavalent Chromium by Viable Cells of Chromium Resistant Bacteria Isolated from Chromite Mining Environment

    Satarupa Dey; Baishali Pandit; A. K. Paul


    Environmental contamination of hexavalent chromium [Cr(VI)] is of serious concern for its toxicity as well as mutagenic and carcinogenic effects. Bacterial chromate reduction is a cost-effective technology for detoxification as well as removal of Cr(VI) from polluted environment. Chromium resistant and reducing bacteria, belonging to Arthrobacter, Pseudomonas, and Corynebacterium isolated from chromite mine overburden and seepage samples of Orissa, India, were found to tolerate 12–18 mM Cr(VI...

  5. Reduction of Chromium-VI by Chromium Resistant Lactobacilli: A Prospective Bacterium for Bioremediation

    Mishra, Ritesh; Sinha, Vartika; Kannan, Ambrose; Upreti, Raj K.


    Chromium is a toxic heavy metal, which primarily exists in two inorganic forms, Cr (VI) and Cr (III). Highly soluble hexavalent chromium is carcinogenic due to its oxidizing nature. It is well established that the intestinal bacteria including Lactobacilli have regulatory effect on intestinal homeostasis and a breakdown in the relationship between intestinal cells and bacteria results in the manifestation of gastrointestinal (GI) disorders. In this study Cr (VI) resistance was developed in La...

  6. Mechanical properties of metal-ceramic systems from nickel-chromium and cobalt-chromium alloys

    Mirković Nemanja


    Background/Aim. Metal-ceramic bond strength and alloys' elastic modulus clearly determine the potential of alloy application, because the ceramic integrity during mastication depends on these two characteristics. The aim of this study was to evaluate metal-ceramic bond strength and elastic modulus of cobalt-chromium alloys in making porcelainfused- to-metal restorations, regarding the application of the most frequent nickel-chromium alloy. Methods. The research was performed as an experimenta...

  7. Chromium-manganese steels of transition class

    Possibilities of nickel replacing by manganese and preparing the same level of mechanical properties as in chromium-nickel steels due to γ-α transformations taking place during property tests, are studied. Chromium-manganese steels with the composition of 0.05-0.1%C, 13-14%Cr, 5.0-6.5%Mn, 0.2-0.5%Si, 0.03-0.13%N, 0.05-0.01%Al and additionally alloyed 0.3-2.0%Cu, 0.05-0.6%V, 0.3-1.0%Mo, 0.02-0.05%Ca in various combinations have been melted. It is shown, that using alloying and heat treatment one can control the phase composition, austenite resistance to martensite transformation during loading and mechanical properties of chromium-manganese steels of the transition class. The use of the phase transformation in the process of testing determines the level of mechanical properties. The optimum development of the transformation accompanied by a sufficient development of processes of hardening and microstresses relaxation permits to obtain a high level of mechanical properties: σsub(B)=1500 MPa, σsub(0.2)-1130MPa, delta=15%, psi=37%, asub(H)=1000 kJ/msup(2) which exceeds the level for chromium-nickel steels. Steels have a lower cost and do not require any complecated heat treatment regime

  8. Defect structure of electrodeposited chromium layers

    Positron annihilation spectroscopy was applied to study the effects of pre-treatment and composition of substrates on the quality and defect structure of electrodeposited thick chromium coatings. The results show that both parameters are important, and a scenario is proposed why the mechanically polished substrate gives more defective film than the electro polished one.

  9. Defect structure of electrodeposited chromium layers

    Marek, T; Vertes, A; El-Sharif, M; McDougall, J; Chisolm, C U


    Positron annihilation spectroscopy was applied to study the effects of pre-treatment and composition of substrates on the quality and defect structure of electrodeposited thick chromium coatings. The results show that both parameters are important, and a scenario is proposed why the mechanically polished substrate gives more defective film than the electro polished one.

  10. Flashlamp-pumped lasing of chromium: GSGG

    Lasing action in chromium-doped gadolinium scandium gallium garnet (Cr:GSGG) is well established for both CW/sup (1)/ and flashlamp/sup (2)/ pumping. This paper describes an investigation of flashlamp-pumped Cr:GSGG lasers and indicates some of the factors which limit performance

  11. Trace Elements Excluding Iron - Chromium and Zinc

    The percentage of middle-aged US adults who are participating in leisure-time physical activities is growing. These adults also seek credible information about specific supplements that the public press routinely describes as necessary to enable increases in physical performance. Chromium and zinc a...


    The full document represents a comprehensive data base that considers all sources of chromium in the environment, the likelihood for its exposure to humans, and the possible consequences to man and lower organisms from its absorption. This information is integrated into a format ...

  13. 29 CFR 1926.1126 - Chromium (VI).


    ... CFR 1926.51 Where skin contact with chromium (VI) occurs, the employer shall provide washing facilities in conformance with 29 CFR 1926.51. Eating and drinking areas provided by the employer shall also... requirements of the Hazard Communication Standard, 29 CFR 1910.1200. (3) Cleaning and replacement. (i)...

  14. 29 CFR 1910.1026 - Chromium (VI).


    ... CFR 1910.141. Where skin contact with chromium (VI) occurs, the employer shall provide washing facilities in conformance with 29 CFR 1910.141. Eating and drinking areas provided by the employer shall also... requirements of the Hazard Communication Standard, 29 CFR 1910.1200. (3) Cleaning and replacement. (i)...

  15. 29 CFR 1915.1026 - Chromium (VI).


    ... CFR 1910.141. Where skin contact with chromium (VI) occurs, the employer shall provide washing facilities in conformance with 29 CFR 1915.97. Eating and drinking areas provided by the employer shall also... requirements of the Hazard Communication Standard, 29 CFR 1910.1200. (3) Cleaning and replacement. (i)...

  16. Chromium(III) and chromium(VI) surface treated galvanized steel for outdoor constructions: environmental aspects.

    Lindström, David; Hedberg, Yolanda; Odnevall Wallinder, Inger


    The long-term degradation of chromium(III) (Zn-Cr(III)) and chromium(VI)-based (Zn-Cr(VI)) surface treatments on galvanized steel and their capacities to hinder the release of zinc induced by atmospheric corrosion at nonsheltered urban and marine exposure conditions for 2 years are investigated. Compared to bare zinc sheet, both surface treatments revealed high corrosion protection abilities and capacities to hinder the release of zinc, still evident after 2 years of exposure. The zinc barrier properties of the thinner Zn-Cr(VI) (10 nm) treatment were during the first 100 days of urban exposure slightly improved compared with Zn-Cr(III) (35 nm). However, their long-term protection capacities were inverse. Released concentrations of total chromium correspond to annual release rates less than 0.000032 (Zn-Cr(III)) and 0.00014 g Cr m(-2) yr(-1) (Zn-Cr(VI)) after 1 year of urban exposure. Aging by indoor storage of the surface treatments prior to outdoor exposure reduced the released Cr concentrations from the surface treatments. No Cr(VI) was released from the aged surfaces but from the freshly exposed Zn-Cr(VI). Marine exposure conditions resulted in a faster reduction of chromate to chromium(III)oxide compared with urban conditions, and a significantly lower amount of both chromium(III) and chromium(VI) released from Zn-Cr(VI) at the marine site compared with the urban site. PMID:20462267

  17. Biological groundwater treatment for chromium removal at low hexavalent chromium concentrations.

    Mamais, Daniel; Noutsopoulos, Constantinos; Kavallari, Ioanna; Nyktari, Eleni; Kaldis, Apostolos; Panousi, Eleni; Nikitopoulos, George; Antoniou, Kornilia; Nasioka, Maria


    The objective of this work is to develop and evaluate biological groundwater treatment systems that will achieve hexavalent chromium reduction and total chromium removal from groundwater at hexavalent chromium (Cr(VI)) groundwater concentrations in the 0-200 μg/L range. Three lab-scale units operated, as sequencing batch reactors (SBR) under aerobic, anaerobic and anaerobic-aerobic conditions. All systems received groundwater with a Cr(VI) content of 200 μg/L. In order to support biological growth, groundwater was supplemented with milk, liquid cheese whey or a mixture of sugar and milk to achieve a COD concentration of 200 mg/L. The results demonstrate that a fully anaerobic system or an anaerobic-aerobic system dosed with simple or complex external organic carbon sources can lead to practically complete Cr(VI) reduction to Cr(III). The temperature dependency of maximum Cr(VI) removal rates can be described by the Arrhenius relationship. Total chromium removal in the biological treatment systems was not complete because a significant portion of Cr(III) remained in solution. An integrated system comprising of an anaerobic SBR followed by a sand filter achieved more than 95% total chromium removal thus resulting in average effluent total and dissolved chromium concentrations of 7 μg/L and 3 μg/L, respectively. PMID:26971177

  18. Nephrotoxic and hepatotoxic effects of chromium compounds in rats

    Laborda, R.; Diaz-Mayans, J.; Nunez, A.


    The nephrotoxic, hepatotoxic and cardiotoxic actions of hexavalent chromium compounds, as well as their effects on lung, blood and circulation may contribute to the fatal outcome of chromium intoxication. Although trivalent chromium have been regarded as relatively biologically inert, there are a few salts of chromium III that have been found to be carcinogenic when inhaled, ingested or brought in contact with the tissues. Sensitive persons and industry workers have been subjects of dermatitis, respiratory tract injuries and digestive ulcers due to chromium compounds. In this work, the authors have studied the effect of trivalent and hexavalent chromium compounds on rats measuring the transaminases (GOT and GPT), urea and creatinine levels in serum of chromium poisoned animals at different times.

  19. A Kinetic Model of Chromium in a Flame


    Chromium has been identified as a carcinogenic metal.Incineration is the useful method for disposal of toxic chromium hazard waste and a chromium kinetic model in a flame is very important to study chromium oxidation.Chromium chemical kinetics over a range of temperatures of a hydrogen/air flame is proposed.Nine chromium compounds and fifty-eight reversible chemical reactions were considered The forward reaction rates are calculated based on the molecular collision approach for unknown ones and Arrhenius's Law for known ones.The backward reaction rates were calculated according to forward reaction rates, the equilibrium constants and chemical thermodynamics.It is verified by several equilibrium cases and is tested by a hydrogen/air diffusion flame.The results show that the kinetic model could be used in cases in which the chromium kinetics play an important role in a flame

  20. The Chromium is an essential element in the human

    The Chromium is an essential element for human and animals, because it a preponderant function in the insulin metabolism as a glucose tolerance factor (GTF). The deficiency of chromium engenders a deterioration in the glucose metabolism due to bad efficiency of insulin. Because the importance of this element an exhaustive reference review was made and this presents some studies realized in laboratory animals and in human beings where it is prove with resuits the effect of chromium over the improvement of patients with non-insulin dependant diabetes. Three substances are presented as chromium active biological forms: a material rich in chromium known as glucose tolerance factor, chromium picolinate and a substance of low molecular weight LMWCr in its forms of apo and holo that contains chromium and it links the insulin receptor and improves its activity. Also this paper presents information about the condition of diabetes in Costa Rica. (Author)

  1. Reaction of chromium(VI) with glutathione or with hydrogen peroxide: identification of reactive intermediates and their role in chromium(VI)-induced DNA damage.

    Aiyar, J; Berkovits, H J; Floyd, R A; Wetterhahn, K E


    The types of reactive intermediates generated upon reduction of chromium(VI) by glutathione or hydrogen peroxide and the resulting DNA damage have been determined. In vitro, reaction of chromium(VI) with glutathione led to formation of two chromium(V) complexes and the glutathione thiyl radical. When chromium(VI) was reacted with DNA in the presence of glutathione, chromium-DNA adducts were obtained, with no DNA strand breakage. The level of chromium-DNA adduct formation correlated with chrom...

  2. Modeling water/lithium bromide absorption chillers in ASPEN Plus

    Highlights: → Single- and double-effect water/lithium bromide absorption chiller designs are numerically modeled using ASPEN. → The modeling procedure is described and the results are compared to published modeling data to access prediction accuracy. → Predictions for the single- and double-effect designs are within 3% and 5%, respectively of published data for all cycle parameters of interest. → The absorption cycle models presented allow investigation of using absorption chillers for waste heat utilization in the oil and gas industry. -- Abstract: Absorption chillers are a viable option for providing waste heat-powered cooling or refrigeration in oil and gas processing plants, thereby improving energy efficiency. In this paper, single- and double-effect water/lithium bromide absorption chiller designs are numerically modeled using ASPEN. The modeling procedure is described and the results are compared to published modeling data to access prediction accuracy. Predictions for the single- and double-effect designs are within 3% and 5%, respectively of published data for all cycle parameters of interest. The absorption cycle models presented not only allow investigation into the benefits of using absorption chillers for waste heat utilization in the oil and gas industry, but are also generically applicable to a wide range of other applications.

  3. Development of copper bromide laser master oscillator power amplifier system

    G N Tiwari; R K Mishra; R Khare; S V Nakhe


    Development of master oscillator power amplifier (MOPA) system of copper bromide laser (CBL) operating at 110 W average power is reported. The spectral distribution of power at green (510.6 nm) and yellow (578.2 nm) components in the output of a copper bromide laser is studied as a function of operating parameters. The electrical input power was varied from 2.6 to 4.3 kW, the pulse repetition frequency (PRF) was changed from 16 to 19 kHz, and the pressure of the buffer gas (neon) was kept fixed at 20 mbar. When the electrical input power was increased to 4.3 kW from 2.6 kW, the tube-wall temperature also increased to 488°C from 426°C but the ratio of the green to yellow power decreased to 1.53 from 3.73. The ratio of green to yellow power decreased to 1.53 from 1.63 when the PRF of the laser was increased to 19 kHz from 16 kHz. These observations are explained in terms of electron temperature, energy levels of transitions, and voltage and current waveforms across the laser head.

  4. Synthesis and Characterization of Mercuric Bromide-Phenothiazine Complexes

    Vidisha A. Alwani


    Full Text Available N-alkylphenothiazines (NAPTZs are biologically active heterocyclic compounds that find extensive applications in the field of medicine. In the pharmaceutical industry, they are used as psychotherapeutic, antiemetic, and antihistaminic drugs. In this study, complexation reactions of mercuric bromide with NAPTZs as principal ligands have been investigated in MeOH medium. Five mercuric bromide complexes of the NAPTZ ligands namely, chlorpromazine hydrochloride (CP.HCl, promethazine hydrochloride (PM.HCl, ethopropazine hydrochloride (EP.HCl, trifluoperazine dihydrochloride (TF.2HCl and thioridazine hydrochloride (TR.HCl have been synthesized. These complexes were subjected to elemental analysis, solubility, molar conductance and magnetic susceptibility, U.V-Vis, I.R, and NMR spectroscopy. The molecular formulations of the complexes have been found to be: [HgBr2(CP2].4H2O; [HgBr2(PM2].2H2O; [HgBr2(EP2]; [HgBr2(TF2].2H2O and [HgBr2(TR2]. Tentative molecular structures have been proposed and presented.

  5. Bromoform formation in ozonated groundwater containing bromide and humic substances

    Cooper, W.J.; Amy, G.L.; Moore, C.A.; Zika, R.G.


    The effect of bromide ion, organic carbon concentration (natural aquatic humic substances), pH, and solar irradiation on the formation of bromoform in ozonated groundwater has been studied. The studies were conducted on four unique samples of groundwater taken from different regions of the Biscayne Aquifer in southern Florida. All other conditions being equal, increases in bromide ion concentrations resulted in increases in CHBr/sub 3/ formation. In three of the four samples, CHBr/sub 3/ formation decreased as the pH level increased from 5 to 9. The fourth sample exhibited an opposite trend whereby the CHBr/sub 3/ concentration increased with increasing pH. Bromoform concentration increased with increased O/sub 3/ concentration over an ozone dosage range of 3.4 to 6.7 mg/L. Ozonated samples placed in sunlight immediately after ozone addition showed a decrease in the formation of CHBr/sub 3/ presumably due to the photodecomposition of HOBr/OBr.

  6. Bromoform formation in ozonated groundwater containing bromide and humic substances

    Copper, W.J. (Florida International Univ., Miami (United States)); Amy, G.L. (Univ. of Arizona, Tucson (United States)); Moore, C.A.; Zika, R.G. (Univ. of Miami, FL (United States))

    The effect of bromide ion, organic carbon concentration (natural aquatic humic substances), pH, and solar irradiation on the formation of bromoform in ozonated groundwater has been studied. The studies were conducted on four unique samples of groundwater taken from different regions of the Biscayne Aquifer in southern Florida. All other conditions being equal, increases in bromide ion concentrations resulted in increases in CHBr{sub 3} formation. In three of the four samples, CHBr{sub 3} formation decreased as the pH level increased from 5 to 9. The fourth sample exhibited an opposite trend whereby the CHBr{sub 3} concentration increased with increasing pH. Bromoform concentration increased with increased O{sub 3} concentration over an ozone dosage range of 3.4 to 6.7 mg/L. Ozonated samples placed in sunlight immediately after ozone addition showed a decrease in the formation of CHBr{sub 3}, presumably due to the photodecomposition of HOBr/OBr.

  7. Design and performance of chromium mist generator

    Tirgar Aram


    Full Text Available Chromium mist generator is an essential tool for conducting researches and making science-based recommendations to evaluate air pollution and its control systems. The purpose of this research was to design and construct a homogenous chromium mist generator and the study of some effective factors including sampling height and distances between samplers in side-by-side sampling on chromium mist sampling method. A mist generator was constructed, using a chromium electroplating bath in pilot scale. Concentration of CrO3 and sulfuric acid in plating solution was 125 g L-1 and 1.25 g L-1, respectively. In order to create permanent air sampling locations, a Plexiglas cylindrical chamber (75 cm height, 55 cm i.d was installed the bath overhead. Sixty holes were produced on the chamber in 3 rows (each 20. The distance between rows and holes was 15 and 7.5 cm, respectively. Homogeneity and effective factors were studied via side-by-side air sampling method. So, 48 clusters of samples were collected on polyvinyl chloride (PVC filters housed in sampling cassettes. Cassettes were located in 35, 50, and 65 cm above the solution surface with less than 7.5 and/or 7.5-15 cm distance between heads. All samples were analyzed according to the NIOSH method 7600. According to the ANOVA test, no significant differences were observed between different sampling locations in side-by-side sampling (P=0.82 and between sampling heights and different samplers distances (P=0.86 and 0.86, respectively. However, there were notable differences between means of coefficient of variations (CV in various heights and distances. It is concluded that the most chromium mist homogeneity could be obtained at height 50 cm from the bath solution surface and samplers distance of < 7.5 cm.

  8. Validation of an automated fluorescein method for determining bromide in water

    Fishman, M. J.; Schroder, L.J.; Friedman, L.C.


    Surface, atmospheric precipitation and deionized water samples were spiked with ??g l-1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0.015 to 0.5 mg l-1 of bromide. The correlation coefficient for the same sets of paired data is 0.9987. Recovery data, except for the surface water samples to which 0.005 mg l-1 of bromide was added, range from 89 to 112%. There appears to be no loss of bromide from solution in either type of container.Surface, atmospheric precipitation and deionized water samples were spiked with mu g l** minus **1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0. 015 to 0. 5 mg l** minus **1 of bromide. The correlation coefficient for the same sets of paired data is 0. 9987. Recovery data, except for the surface water samples to which 0. 005 mg l** minus **1 of bromide was added, range from 89 to 112%. Refs.

  9. Chromium supplementation improved post-stroke brain infarction and hyperglycemia.

    Chen, Wen-Ying; Mao, Frank Chiahung; Liu, Chia-Hsin; Kuan, Yu-Hsiang; Lai, Nai-Wei; Wu, Chih-Cheng; Chen, Chun-Jung


    Hyperglycemia is common after acute stroke and is associated with a worse outcome of stroke. Thus, a better understanding of stress hyperglycemia is helpful to the prevention and therapeutic treatment of stroke. Chromium is an essential nutrient required for optimal insulin activity and normal carbohydrate and lipid metabolism. Beyond its nutritional effects, dietary supplement of chromium causes beneficial outcomes against several diseases, in particular diabetes-associated complications. In this study, we investigated whether post-stroke hyperglycemia involved chromium dynamic mobilization in a rat model of permanent focal cerebral ischemia and whether dietary supplement of chromium improved post-stroke injury and alterations. Stroke rats developed brain infarction, hyperglycemia, hyperinsulinemia, glucose intolerance, and insulin resistance. Post-stroke hyperglycemia was accompanied by elevated secretion of counter-regulatory hormones including glucagon, corticosterone, and norepinephrine, decreased insulin signaling in skeletal muscles, and increased hepatic gluconeogenesis. Correlation studies revealed that counter-regulatory hormone secretion showed a positive correlation with chromium loss and blood glucose increased together with chromium loss. Daily chromium supplementation increased tissue chromium levels, attenuated brain infarction, improved hyperglycemia, and decreased plasma levels of glucagon and corticosterone in stroke rats. Our findings suggest that stroke rats show disturbance of tissue chromium homeostasis with a net loss through urinary excretion and chromium mobilization and loss might be an alternative mechanism responsible for post-stroke hyperglycemia. PMID:26477944

  10. Effective adsorption of hexavalent chromium through a three center (3c) co-operative interaction with an ionic liquid and biopolymer

    Highlights: ► Tetraoctylammoniumbromide impregnated chitosan was prepared by ultrasonication. ► Physico-chemical characterization of the adsorbent was studied in detail. ► The sorbent has an adsorption capacity of 63.69 mg g−1 for chromium(VI). ► The mechanism involves a three center interaction with positive co-operative effect. ► Adsorbent is effectively regenerated with ammonium hydroxide. - Abstract: Biopolymers as well as ionic liquids are known for their potential applications. In this work, we report the utility of chitosan as an excellent platform for impregnating the ionic liquid, tetraoctylammonium bromide by ultrasonication and its subsequent adsorption for chromium(VI). The effective mass transfer due to sonication coupled with the hydrogen bonding interaction between chitosan-ionic liquid and the electrostatic interaction involving the amino groups in chitosan and hexavalent chromium governs this three center (3c) co-operative mechanism. The adsorption followed a pseudo second order kinetics with a Langmuir adsorption capacity of 63.69 mg g−1. Various isotherm models were used to correlate the experimental data and the adsorption process is exothermic with a decreased randomness at the solid–solution interface. The thermodynamics of the spontaneous adsorption process could be explained through a positive co-operative effect between the host (chitosan) and the guest (ionic liquid). The adsorbed chromium(VI) could be converted to ammonium chromate using ammonium hydroxide, thereby regenerating the adsorbent. The method could be translated into action in the form of practical application to a real sample containing chromium.

  11. Determination of micro-amount bromide in uranium trioxide by spectrophotometric method

    The content of bromide in the production of uranium trioxide is one of the most important control factors, so determining it accurately seems important. When uranium trioxide is dissolved in nitric acid, in the presence of AgNO3 solution, micro-amount bromide can be co- precipitated with AgCl. Bromide can be separated by centrifugation from a large amount of UO22+ and other anions. In the existing of KOH and H2O2, AgCl can be changed into free bromide. By adding ammonium molybdate as catalyst, bromide and excessive KBrO3 can react and produce Br2. In the medium of tert-butanol-ethanol, Br2 can react with basic fuchsine and produce a purple compound which is stable, the bromide content is determined by spectrophotometric method. The results show that it is a highly sensitive method with low detection limit. Its apparent molar absorption coefficient κ' is 1.7 x 104 L/(mol·cm). Its detection limit is 9 μg/L and determination limit is 0.13 mg/L. The linear relationship is in the range of 0.2-1.6 mg/L with a correlation coefficient of 0.997. The relative standard deviation is less than 10% after it is determed six times at the same time. For bromide content of 4.00 and 8.00 μg, the bromide recovery obtained are between 94% and 103%. (authors)

  12. Removal of bromide by aluminium chloride coagulant in the presence of humic acid.

    Ge, Fei; Shu, Haimin; Dai, Youzhi


    Bromide can form disinfection by-products (DBPs) in drinking water disinfection process, which have adverse effects on human health. Using aluminium chloride as a model coagulant, removal of bromide by coagulation was investigated in the absence or presence of humic acid (HA) in synthetic water and then was conducted in raw water. Results demonstrated that in synthetic water, 93.3-99.2% removal efficiency of bromide was achieved in the absence of HA with 3-15 mg/L coagulant, while 78.4-98.4% removal efficiency of bromide was obtained in the presence of HA with the same coagulant dosage and 86.8-98.8% HA was removed simultaneously. Bromide in raw water was removed 87.0% with 15 mg/L coagulant. HA apparently reduced the removal of bromide with low coagulant dosage or at high pH, while minor influence on removal of bromide was observed with high coagulant dosage or at low pH. Thus, bromide could be reduced effectively by enhanced coagulation in drinking water treatment. PMID:17289257




    A series of hydrophobically modified homo- and copolymers of the poly(alkylmethyldiallylammonium bromide) type has been prepared by free-radical cyclo(co)polymerization of alkylmethyldiallylammonium bromide monomers in aqueous solution. Depending on the length of the alkyl side chain (varied between

  14. Acrolein as Potential Alternative to Methyl Bromide in California-Grown Calla Lilies

    Cut flower and ornamental bulb industries rely heavily on a methyl bromide/chloropicrin (MB/Pic) mixture as a key pest management tool. The loss of methyl bromide (MB) will seriously affect the cut flower and bulb industry, and in the future, will require growers to use alternative fumigants. Theref...

  15. The method of molecular dynamics in ethidium bromide-DNA interaction research

    The interaction of ethidium bromide with the DNA by the method of molecular dynamics was studied. The geometric and energy parameters of DNA-ethidium bromide connectivity had been calculated. A comparative analysis of the experimentally identified connectivity parameters by different methods and parameters of molecular dynamics method had been carried out

  16. Femtosecond laser surface structuring and oxidation of chromium thin coatings: Black chromium

    Kotsedi, L., E-mail: [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, P.O. Box 722, Somerset West, Western Cape (South Africa); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, P.O. Box 722, Somerset West, Western Cape (South Africa); Mthunzi, P. [National Laser Centre, Council for Scientific and Industrial Research, 0001 Pretoria (South Africa); Muller, T.F.G. [University of the Western Cape, Physics Department, Bellville, 7535 Cape Town (South Africa); Eaton, S.M. [Physics Department, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Julies, B. [University of the Western Cape, Physics Department, Bellville, 7535 Cape Town (South Africa); Manikandan, E. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, P.O. Box 722, Somerset West, Western Cape (South Africa); Ramponi, R. [Physics Department, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, P.O. Box 722, Somerset West, Western Cape (South Africa)


    Highlights: • Oxidation of the chromium thin film to chromium oxide by femtosecond laser with a fundamental wavelength of 1064 nm. • Solar absorber from chromium oxide that low percentage reflectance. • Femtosecond laser oxidation, with a de-focused laser. • Chromium oxide formation by femtosecond laser in normal ambient. - Abstract: In view of their potential applications as selective solar absorbers, chromium coatings on float glass substrates were nano/micro structured by femtosecond laser in air. Raman and X-rays diffraction investigations confirmed the formation of an ultra-porous α-Cr{sub 2}O{sub 3} layer at the surface; higher is the input laser power, enhanced is the crystallinity of the α-Cr{sub 2}O{sub 3} layer. The α-Cr{sub 2}O{sub 3} layer with the Cr underneath it in addition to the photo-induced porosity acted as a classical ceramic–metal nano-composite making the reflectance to decrease significantly within the spectral range of 190–1100 nm. The average reflectance decreased from 70 to 2%.

  17. Femtosecond laser surface structuring and oxidation of chromium thin coatings: Black chromium

    Highlights: • Oxidation of the chromium thin film to chromium oxide by femtosecond laser with a fundamental wavelength of 1064 nm. • Solar absorber from chromium oxide that low percentage reflectance. • Femtosecond laser oxidation, with a de-focused laser. • Chromium oxide formation by femtosecond laser in normal ambient. - Abstract: In view of their potential applications as selective solar absorbers, chromium coatings on float glass substrates were nano/micro structured by femtosecond laser in air. Raman and X-rays diffraction investigations confirmed the formation of an ultra-porous α-Cr2O3 layer at the surface; higher is the input laser power, enhanced is the crystallinity of the α-Cr2O3 layer. The α-Cr2O3 layer with the Cr underneath it in addition to the photo-induced porosity acted as a classical ceramic–metal nano-composite making the reflectance to decrease significantly within the spectral range of 190–1100 nm. The average reflectance decreased from 70 to 2%

  18. Production of basic chromium sulfate by using recovered chromium from ashes of thermally treated leather.

    Dettmer, Aline; Nunes, Keila Guerra Pacheco; Gutterres, Mariliz; Marcílio, Nilson Romeu


    Leather wastes tanned with chromium are generated during the production process of leather, hence the wastes from hand crafted goods and footwear industries are a serious environmental problem. The thermal treatment of leather wastes can be one of the treatment options because the wastes are rich in chromium and can be used as a raw material for sodium chromate production and further to obtain several chromium compounds. The objective of this study was to utilize the chromium from leather wastes via basic chromium sulfate production to be subsequently applied in a hide tanning. The obtained results have shown that this is the first successful attempt to achieve desired base properties of the product. The result was achieved when the following conditions were applied: a molar ratio between sodium sulfite and sodium dichromate equal to 6; reaction time equal to 5 min before addition of sulfuric acid; pH of sodium dichromate solution equal to 2. Summarizing, there is an opportunity to utilize the dangerous wastes and reused them in the production scheme by minimizing or annulling the environmental impact and to attend a sustainable process development concept. PMID:20031309

  19. Xanthine Biosensor Based on Didodecyldimethylammonium Bromide Modified Pyrolytic Graphite Electrode

    TANG,Ji-Lin(唐纪琳); HAN,Xiao-Jun(韩晓军); HUANG,Wei-Min(黄卫民); WANG,Er-Kang(汪尔康)


    The vesicle of didodecyldimethylammonium bromide (DDAB)which contained tetrathiafulvalene (TTF) was mixed with xanthine oxidase, and the mixture was cast on the pyrolytic graphite electrode. The lipid films were used to supply a biological environment resembling biomembrane on the surface of the electrode. TTF was used as a mediator because of its high electron-transfer efficiency. A novel xanthine biosensor based on cast DDAB film was developed. The effects of pH and operating potential were explored for optimum analytical performance by using the amperometric method. The response time of the biosensor was less than 10 s. The detection limit of the biosensor was 3.2 × 10-7 mol/L and the liner range was from 4 × 10-7 mol/L to 2.4 × 10-6 mol/L.

  20. Solvent effects in the reaction between piperazine and benzyl bromide

    S Ranga Reddy; P Manikyamba


    The reaction between piperazine and benzyl bromide was studied conductometrically and the second order rate constants were computed. These rate constants determined in 12 different protic and aprotic solvents indicate that the rate of the reaction is influenced by electrophilicity (), hydrogen bond donor ability () and dipolarity/polarizability (*) of the solvent. The LSER derived from the statistical analysis indicates that the transition state is more solvated than the reactants due to hydrogen bond donation and polarizability of the solvent while the reactant is more solvated than the transition state due to electrophilicity of the solvent. Study of the reaction in methanol, dimethyl formamide mixtures suggests that the rate is maximum when dipolar interactions between the two solvents are maximum.

  1. Timing resolution measurements of a 3 in. lanthanum bromide detector

    Galli, L., E-mail: [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); De Gerone, M. [INFN Sezione di Genova, Largo Dodecaneso 33, 16146 Genova (Italy); Dipartimento di Fisica dell' Università degli Studi di Genova, Largo Dodecaneso 33, 16146 Genova (Italy); Dussoni, S. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Nicolò, D. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica dell' Università degli Studi di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Papa, A. [Paul Scherrer Institute PSI, CH-5232 Villigen (Switzerland); Tenchini, F. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica dell' Università degli Studi di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Signorelli, G. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy)


    Cerium-doped lanthanum bromide (LaBr{sub 3}:Ce) is a scintillator that presents very good energy and timing resolutions and it is a perfect candidate for photon detector in future experiments to search for lepton flavor violation as in μ→eγ or μ→e conversion. While energy resolution was thoroughly investigated, timing resolution at several MeV presents some experimental challenge. We measured the timing resolution of a 3 in.×3 in. cylindrical LaBr{sub 3}(Ce) crystal versus few reference detectors by means of a nuclear reaction from a Cockcroft–Walton accelerator that produces coincident γ-rays in the 4.4–11.6 MeV range. Preliminary results allow us to extrapolate the properties of a segmented γ-ray detector in the 50–100 MeV range.

  2. Optical studies of X-irradiated sodium bromide single crystals

    Optical absorption of sodium bromide single crystals colored by X-rays for durations ranging from 8 hours to 200 hours at room temperature has been studied. Two well-resolved absorption bands one at 535 nm (F-band) and the other at 255 nm have been observed in all the samples. Another band at 840 nm (M-band) has also been observed when the irradiation time was extended to 200 hours. A band at 770 nm has been detected for the first time during the process of optical bleaching. The effects of optical bleaching with F-band light on these absorption bands have been studied in detail for durations ranging from a few seconds to 1820 minutes at temperature below the coloration temperature. (author)

  3. Irradiation as an alternative to methyl bromide: the Australian situation

    International agreement to phase out the fumigant Methyl bromide (MeBr) will have serious implications for pest and disease control in Australia, particularly grain pest control, quarantine usage on fresh horticultural produce and control of soil pathogens or nematodes. Irradiation is a practical alternative but is not currently approved for use in Australia. Other options are available but none of the viable methods except irradiation have the short application time needed for treatment of grams found to be infested during loading at export. This usage is vital, as Australian grain is exported at very high standards of freedom from insects, assured by Government regulatory requirements. Irradiation is contrasted against other alternatives including heat and cold, especially for fresh horticultural produce. (author)

  4. Mechanism of the Deaquation of Aquopentaaminocobalt(Ⅲ) Bromide

    MA,Li-Dun(马礼敦); CHENG,Guang-Hui(程广辉); WU,Hong-Xiang(吴宏翔); LIN,Han-Yi(林涵毅); SHEN,Xiao-Liang(沈孝良); SHI,Guo-Shun(施国顺)


    There are two theories, SN1 and SN2, for the mechanism of the deaquation of aquopentaamincobalt(Ⅲ) bromide (AAC-B).Both of the theories are supported by some experimental and calculated data. But there are not any experiments to determine directly the structure of the intermediates at different reaction time. In this paper the structures of the intermediates at different reaction time in deaquation-anation of AACB were de-termined by extended X-ray absorption fine structure (EXAFS)and the reaction process wes studied by the combination of Xray powder diffraction and EXAFS. It was demonstrated that the deaquation-anation of AACB obeys the SN2 theory.

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

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

  6. Inelastic Scattering of Neutrons in Chromium

    The phonon spectrum of chromium has been studied by neutron inelastic scattering. The dispersion curves are very similar, in form to those of tungsten and molybdenum, indicating similar interionic force constants. The neutron groups broaden but do not shift appreciably when the temperature is raised. No effect has been observed which can be attributed to the interaction between the phonons and the crystal magnetization in the antiferromagnetic phase. (author)

  7. Observational Approach to Chromium Site Remediation - 13266

    Production reactors at the U.S. Department of Energy's (DOE) Hanford Site in Richland, Washington, required massive quantities of water for reactor cooling and material processing. To reduce corrosion and the build-up of scale in pipelines and cooling systems, sodium dichromate was added to the water feedstock. Spills and other releases at the makeup facilities, as well as leaks from miles of pipelines, have led to numerous areas with chromium-contaminated soil and groundwater, threatening fish populations in the nearby Columbia River. Pump-and-treat systems have been installed to remove chromium from the groundwater, but significant contamination remain in the soil column and poses a continuing threat to groundwater and the Columbia River. Washington Closure Hanford, DOE, and regulators are working on a team approach that implements the observational approach, a strategy for effectively dealing with the uncertainties inherent in subsurface conditions. Remediation of large, complex waste sites at a federal facility is a daunting effort. It is particularly difficult to perform the work in an environment of rapid response to changing field and contamination conditions. The observational approach, developed by geotechnical engineers to accommodate the inherent uncertainties in subsurface conditions, is a powerful and appropriate method for site remediation. It offers a structured means of quickly moving into full remediation and responding to the variations and changing conditions inherent in waste site cleanups. A number of significant factors, however, complicate the application of the observational approach for chromium site remediation. Conceptual models of contamination and site conditions are difficult to establish and get consensus on. Mid-stream revisions to the design of large excavations are time-consuming and costly. And regulatory constraints and contract performance incentives can be impediments to the flexible responses required under the observational

  8. Stainless chromium-nickel steels. Chapter I

    The chemical composition is tabulated of 90 chromium-nickel stainless steels and alloys given in volume %. The values are also given of the corrosion resistance of the steels and alloys. The tables show data on the surface condition or the methods of material working, types and chemical composition of the medium where corrosion resistance tests were carried out, temperature, pressure, time of tests, corrosion rates, corrosion types, and literature references. A total of 35 references is given. (J.B.)

  9. Loading chromium atoms in a magnetic guide

    Greiner, A; Sebastian, J.; Rehme, P.; Aghajani-Talesh, A.; Griesmaier, A.; Pfau, T.


    We have realized a magnetic guide for ultracold chromium atoms by continuously loading atoms directly from a Zeeman slower into a horizontal guide. We observe an atomic flux of $2 \\cdot 10^7$ atoms/s and are able to control the mean velocity of the guided atoms between 0 m/s and 3 m/s. We present our experimental results on loading and controlling the mean velocity of the guided atoms and discuss the experimental techniques that are used.

  10. X-616 Chromium Sludge Lagoons pictorial overview, Piketon, Ohio

    The Portsmouth Gaseous Diffusion Plant uses large quantities of water for process cooling. The X-616 Liquid Effluent Control Facility was placed in operation in December 1976 to treat recirculation cooling water blowdown from the process cooling system. A chromium-based corrosion inhibitor was used in the cooling water system. A chromium sludge was produced in a clarifier to control chromium levels in the water. Chromium sludge produced by this process was stored in two surface impoundments called the X-616 Chromium Sludge Lagoons. The sludge was toxic due to its chromium concentration and therefore required treatment. The sludge was treated, turning it into a sanitary waste, and buried in an Ohio EPA approved landfill. The plant's process cooling water system has changed to a more environmentally acceptable phosphate-based inhibitor. Closure activities at X-616 began in August 1990, with all construction activities completed in June 1991, at a total cost of $8.0 million

  11. Chromium oxidation state mapping in human cells

    Ortega, R.; Fayard, B.; Salomé, M.; Devès, G.; Susini, J.


    The widespread use of chromium in industrial applications such as chemical production of pigments, refractory brick production, tanning, metallurgy, electroplating, and combustion of fuels has lead to human occupational exposure and to its increased introduction into the environment. Hexavalent chromium compounds are established carcinogens but their mechanism of cell transformation is not known. Up to now, no microanalytical technique was sensitive enough to allow the observation of chromium distribution, and oxidation state identification, within isolated cells at carcinogenic concentrations. In this experiment, we used successfully the ID-21 X-ray microscope to map Cr(VI) and total Cr distributions in cells exposed in vitro to soluble, and insoluble, Cr(VI) compounds. Exposure to soluble compounds, weak carcinogens, resulted in a homogeneous intracellular distribution of Cr, confirming by in situ measurement that Cr is present in the cell nucleus. Cr(VI) was never detected in cells which suggests a mechanism of rapid intracellular reducticn. On the other hand, exposure to insoluble compounds, strong carcinogens, also resulted in a homogeneous distribution of reduced forms of Cr in cells, and their nucleus. However, in this case, Cr(VI)-rich structures were observed into the cells suggesting that carcinogenicity is enhanced when oxidation reactions due to Cr(VI) chronic exposure are associated to Cr-DNA alterations.

  12. Dimensionally Controlled Lithiation of Chromium Oxide

    Fister, Tim T. [Argonne National Lab. (ANL), Argonne, IL (United States); Hu, Xianyi [Northwestern Univ., Evanston, IL (United States); Esbenshade, Jennifer [Univ. of Illinois, Urbana-Champaign, IL (United States); Chen, Xiao [Northwestern Univ., Evanston, IL (United States); Wu, Jinsong [Northwestern Univ., Evanston, IL (United States); Dravid, Vinayak [Northwestern Univ., Evanston, IL (United States); Bedzyk, Michael [Northwestern Univ., Evanston, IL (United States); Long, Brandon [Argonne National Lab. (ANL), Argonne, IL (United States); Gewirth, Andrew A. [Univ. of Illinois, Urbana-Champaign, IL (United States); Shi, Bing [Argonne National Lab. (ANL), Argonne, IL (United States); Schlepütz, Christian M. [Argonne National Lab. (ANL), Argonne, IL (United States); Fenter, Paul [Argonne National Lab. (ANL), Argonne, IL (United States)


    Oxide conversion reactions are an alternative approach for high capacity lithium ion batteries but are known to suffer from structural irreversibility associated with the phase separation and reconstitution of reduced metal species and Li2O. In particular, the morphology of the reduced metal species is thought to play a critical role in the electrochemical properties of a conversion material. Here we use a model electrode with alternating layers of chromium and chromium oxide to better understand and control these phase changes in real-time and at molecular length scales. Despite lacking crystallinity at the atomic scale, this superstructure is observed (with X-ray reflectivity, XR) to lithiate and delithiate in a purely one-dimensional manner, preserving the layered structure. The XR data show that the metal layers act as nucleation sites for the reduction of chromium in the conversion reaction. Irreversibility during delithiation is due to the formation of a ternary phase, LiCrO2, which can be further delithiated at higher potentials. The results reveal that the combination of confining lithiation to nanoscale sheets of Li2O and the availability of reaction sites in the metal layers in the layered structure is a strategy for improving the reversibility and mass transport properties that can be used in a wide range of conversion materials.

  13. Chromium--a material for fusion technology

    Due to their low neutron-induced radioactivity chromium based materials are considered to be candidates for structure materials in fusion technology. In this paper investigations are presented of unirradiated chromium with a purity of 99.96% (DUCROPUR) and a dispersion strengthened chromium alloy Cr5Fe1Y2O3 (DUCROLLOY). Both materials have been produced in a powder metallurgical route. Mechanical tests of smooth and pre-cracked specimens have been performed in a wide temperature range. Below 280 deg. C the fracture toughness values of DUCROPUR are very low (1/2), above the transition temperature they exceed 500 MPa m1/2. Large plastic deformations have been observed. DUCROLLOY does not indicate such a significant increase of fracture toughness in the tested temperature range. But above 400 deg. C large plastic deformations can be obtained in bending samples, too. The fatigue crack propagation behaviour of DUCROPUR at 300 deg. C is similar to that of a ductile metal


    Inga Zinicovscaia


    Due to its widespread industrial use, chromium has become a serious pollutant in diverse environmental settings. The main source of chromium pollution including the Republic o Moldova is industry. It is a great need to develop new eco-friendly methods of chromium removal. Biosorption of heavy metals is a most promising technology involved in the removal of toxic metals from industrial waste streams and natural waters. This article is an extended abstract of a communication presented at the...


    A. Chidambaram ، P. Sundaramoorthy ، A. Murugan ، K. Sankar Ganesh ، L. Baskaran


    Chromium is known to be highly toxic to biological systems. This study was designed to determine the mutagenic effects of different concentrations (0, 10, 25, 50, 100 and 200 mg/L) of hexavalent chromium on root tip cells of blackgram (Vigna mungo L. Hepper). The blackgram seeds were equi-spacially arranged in sterilized petriplates lined with filter paper and they were treated with different concentrations of chromium solution. In germination studies, the morphological growth parameters such...

  16. Processes affecting the remediation of chromium-contaminated sites.

    Palmer, C.D.; Wittbrodt, P R


    The remediation of chromium-contaminated sites requires knowledge of the processes that control the migration and transformation of chromium. Advection, dispersion, and diffusion are physical processes affecting the rate at which contaminants can migrate in the subsurface. Heterogeneity is an important factor that affects the contribution of each of these mechanisms to the migration of chromium-laden waters. Redox reactions, chemical speciation, adsorption/desorption phenomena, and precipitat...

  17. Analysis of molybdenum, chromium, vanadium and iron by polarographic techniques

    The application of direct current Tast polarograph, differential pulse polarography and phase-selective alternative current Tast polarography to the problem of determining molybdenum, chromium, vanadium and iron in various supporting electrolytes is reported. The effect of the supporting electrolyte on the wave/peak potential and sensitivity of the metal ion have been examined. The polarographic methods were applied for simultaneous determination of chromium (3)/chromium (6), vanadium (4), vanadium (5) and iron (2)/iron (3) in different supporting electrolytes

  18. Production of a chromium Bose-Einstein condensate

    Griesmaier, Axel; Stuhler, Jürgen; Pfau, Tilman


    The recent achievement of Bose-Einstein condensation of chromium atoms [1] has opened longed-for experimental access to a degenerate quantum gas with long-range and anisotropic interaction. Due to the large magnetic moment of chromium atoms of 6 {$\\mu$}B, in contrast to other Bose- Einstein condensates (BECs), magnetic dipole-dipole interaction plays an important role in a chromium BEC. Many new physical properties of degenerate gases arising from these magnetic forces have been predicted in ...

  19. Removal of chromium(VI) from saline wastewaters by

    AKSU, Zümriye


    Some industrial wastewaters contain higher quantities of salts besides chromium(VI) ions so the effect of these salts on the biosorption of chromium(VI) should be investigated. The biosorption of chromium (VI) from saline solutions on two strains of living Dunaliella algae were tested under laboratory conditions as a function of pH, initial metal ion and salt (NaCl) concentrations in a batch system. The biosorption capacity of both Dunaliella strains strongly de...

  20. Increase of chromium utilization in stainless steel melting

    The processes of deoxidizing when melting stainless 18-10 steels in electric are furnaces by the method of remelting with wastes are investigated. The dependences of amount of reduced chromium on silicon consumption are made more precise. It is shown that it is useful to apply aluminium for deoxidation of acid high-chromium slags. Based on the data on pilot melts the extent to which aluminium can be used as a reducing agent for chromium is estimated. 3 refs., 2 figs

  1. Scientific Opinion on ChromoPrecise® cellular bound chromium yeast added for nutritional purposes as a source of chromium in food supplements and the bioavailability of chromium from this source

    EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS)


    The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of ChromoPrecise® cellular bound chromium yeast added for nutritional purposes as a source of chromium in food supplements and the bioavailability of chromium from this source. ChromoPrecise® is a yeast preparation with an enriched trivalent chromium content, obtained by culture of Saccharomyces cerevisiae in the presence of chromium chloride. A daily intake of 100 µg ch...

  2. Chromium depletion from stainless steels during vacuum annealing

    The behaviour of chromium during selective evaporation by high temperature vacuum annealing has been investigated by means of energy dispersive X-ray analysis and by neutron activation analysis. It was established that the rate of chromium loss from austenitic stainless steels 316 and 321 is controlled by chromium inter-diffusion rather than tracer diffusion in the alloy. Two important parameters in selective removal of chromium from alloy steels are the variation in the chromium surface concentration with time and the depletion profile in the alloy. The present work gives support for the model in which loss of chromium is dependent on its diffusivity in the alloy and on an interface transfer coefficient. The results showed that the surface concentration of chromium decreased with increasing vacuum annealing time. The chromium depletion profile in the metal was in accord with the previous derived model, apart from an anomalous near surface region. Here the higher resolution of a neutron activation technique indicated a region within approximately 2 microns of the surface where the chromium concentration decreased more steeply than expected. (author)

  3. Stabilization and solidification of chromium-contaminated soil

    Cherne, C.A.; Thomson, B.M. [Univ. of New Mexico, Albuquerque, NM (United States). Civil Engineering Dept.; Conway, R. [Sandia National Labs., Albuquerque, NM (United States)


    Chromium-contaminated soil is a common environmental problem in the United States as a result of numerous industrial processes involving chromium. Hexavalent chromium [Cr(VI)] is the species of most concern because of its toxicity and mobility in groundwater. One method of diminishing the environmental impact of chromium is to reduce it to a trivalent oxidation state [Cr(III)], in which it is relatively insoluble and nontoxic. This study investigated a stabilization and solidification process to minimize the chromium concentration in the Toxicity Characteristic Leaching Procedure (TCLP) extract and to produce a solidified waste form with a compressive strength in the range of 150 to 300 pounds per square inch (psi). To minimize the chromium in the TCLP extract, the chromium had to be reduced to the trivalent oxidation state. The average used in this study was an alluvium contaminated with chromic and sulfuric acid solutions. The chromium concentration in the in the in situ soil was 1212 milligrams per kilogram (mg/kg) total chromium and 275 mg/kg Cr(VI). The effectiveness of iron, ferrous sulfate to reduce Cr(VI) was tested in batch experiments.

  4. Method of trivalent chromium concentration determination by atomic spectrometry

    Reheulishvili, Aleksandre N.; Tsibakhashvili, Neli Ya.


    A method is disclosed for determining the concentration of trivalent chromium Cr(III) in a sample. The addition of perchloric acid has been found to increase the atomic chromium spectrometric signal due to Cr(III), while leaving the signal due to hexavalent chromium Cr(VI) unchanged. This enables determination of the Cr(III) concentration without pre-concentration or pre-separation from chromium of other valences. The Cr(III) concentration may be measured using atomic absorption spectrometry, atomic emission spectrometry or atomic fluorescence spectrometry.

  5. Tribological Characteristics of Chromium-active Carbon Electroplated Composite Coatings

    GUKa-fi; HUAMeng; Yi-min


    A process of chromium electroplating using a standard bath with additives and active carbon particles was reported, and the tribological behaviors of the composite coatings using the pin-on-disk tester and the table wear tester were i nvestig(aed. Experimental results indicate that the electroplated chromium-active carbon composite coatings exhibited the low friction coefficient anti excellent anti-wear properties whets coffered with the normal chromium electroplated ones. The formation of active carbon particles within the chromium matrices can be explained by SEM analysis and the mechanis of wear resistance of the composite coatings were studied.

  6. Defect transformation in GSGG crystals during chromium ion activation

    Absorption and induced absorption spectra, dose dependence of induced absorption, thermoluminescence of GSGG crystals, nominally pure and activated with chromium and neodymium ions in different concentrations, are investigated. It is shown that it is chromium ion presence in large concentration that decreases the induced coloration in GSGG crystals after γ-irradiation at 300 K. Optimum concentration of chromium ions for the minimum of induced coloration are found. The mechanism of decrease of induced coloration consisting in Fermi level displacement by chromium ion activation is established. Defect concentration and localization and recombination possibilities of electrons and holes in GSGG crystals are estimated by computer simulation

  7. Oral bioavailability of chromium from a specific site.

    Witmer, C M; Harris, R.; Shupack, S I


    Analysis of soil from a specific site in New Jersey indicated a low level of sodium and chromium present as a calcium compound. Chromium was then administered orally to young, mature male rats at a level of 240 micrograms/kg for 14 days as chromium-contaminated soil, as CaCrO4, and as an equimolar mixture of the soil and calcium salts for 14 days. The rats were sacrificed 24 hr after the last dosing, and tissues were taken immediately for chromium analysis. Blood, muscle, and liver contained ...


    Igata, N.; Sato, S; ANDO, T.; H. Doi; Nishikawa, O.; Shibata, M.


    The objective of this investigation is to clarify the behavior of chromium atoms in iron-5at.% chromium alloy. When the specimens were quenched after soultion annealing at 1150°C for 1hr, FIM image was only a bright area, but when they were tempered from 450°C to 650°C, both bright areas and dark areas were observed in the FIM image. In these quenched specimens there was microsegregation of chromium atoms : In bright areas the chromium concentration was lower, and in dark areas it was higher ...

  9. Influence of Chelating Agents on Chromium Fate in Sediment



    A laboratory investigation on reaction between chelating agents and chromium was conducted to evaluate the effect of chelating agents on the adsorption and desorption of chromium in sediment.The amount of adsorbed chromium(VI) in sediment decreased slightly by 5%-10% because of addition of chelating agents.Chelating agents inhibited the removal of Cr(Ⅲ)by sediment from solutions and the inhibiting effect was in the order:citric acid>tartaric acid>EDTA,Salicylic acid.No effect of chelating agents on desorption of chromium in sediment was observed.

  10. Analysing the chromium-chromium multiple bond using multiconfigurational quantum chemistry

    Brynda, Marcin; Gagliardi, Laura; Roos, Björn O.


    This Letter discusses the nature of the chemical bond between two chromium atoms in different di-chromium complexes with the metal atoms in different oxidation states. Starting with the Cr diatom, with its formally sextuple bond and oxidation number zero, we proceed to analyse the bonding in some Cr(I)–Cr(I) XCrCrX complexes with X varying from F, to Phenyl, and Aryl. The bond distance in these complexes varies over a large range: 1.65–1.83 Å and we suggest explanations for these variations. ...

  11. The effect of chromium picolinate on serum cholesterol and apolipoprotein fractions in human subjects.

    Press, R. I.; Geller, J.; Evans, G. W.


    Chromium has been implicated as a cofactor in the maintenance of normal lipid and carbohydrate metabolism. A deficiency of chromium results from diets low in biologically available chromium. Picolinic acid, a metabolite of tryptophan, forms stable complexes with transitional metal ions, which results in an improved bioavailability of the metal ion chromium. To determine whether or not chromium picolinate is effective in humans, 28 volunteer subjects were given either chromium tripicolinate (3...

  12. The reactivity of phenancyl bromide under β-cyclodextrin as supramolecular catalyst: a computational survey.

    Wan, Yali; Wang, Xueye; Liu, Na


    Phenacyl bromide as one starting material in multicomponent reactions (MCRs) with β-cyclodextrin (β-CD) as catalyst can get an excellent yield in short reaction times. The interaction of β-CD with phenacyl bromide plays an important role in this process. This paper studies the complex of β-CD with phenacyl bromide using density functional theory (DFT) method. Energy is investigated to find out the lowest energy of two possible complexation models. Hydrogen bonds are researched on the basis of natural bonding orbital (NBO) analysis. The relative position between phenacyl bromide and β-CD is confirmed by (1)H nuclear magnetic resonance ((1)HNMR). The results of frontier molecular orbitals and charge distribution reveal that β-CD catalyst improves the reactivity and electrophilicity of phenacyl bromide, meanwhile, the carbonyl group of phenacyl bromide more easily gives a carbocationic intermediate in the presence of β-CD as catalyst. The reactivity of phenancyl bromide under β-CD as supramolecular catalysis is improved. PMID:25929992

  13. The Effect of Chromium Added into Basal Diet on Serum Total Protein, Urea, Triglyceride, Cholesterol and Serum and Tissue Chromium, Zinc, Copper Levels in Rabbits

    *, Kâzim ŞAHİN; *, Talat GÜLER; +, N. ŞAHİN; *, O. N. ERTAS; +, N. ERKAL


    This study was conducted to determine the effect of supplemantal dietary chromium on serum total protein, urea, triglycerides, cholesterol, and serum and tissue chromium, zinc, and copper contents of pregnant rabbits, their offspring and their young rabbits. Treatment groups consisted of chromium level as follows: Control Group no supplementation chromium into basal diet, Treatment I (200 ppb Group) contained 200 ppb of supplemental chromium into basal diet, and Treatment II (400 ppb Group...

  14. Methyl bromide cycling in a warm-core eddy of the North Atlantic Ocean

    Yvon-Lewis, SA; Butler, JH; Saltzman, Es; Matrai, PA; King, DB; R. Tokarczyk; Moore, RM; Zhang, JZ


    We conducted a detailed investigation of the evolution of methyl bromide concentrations, degradation rates, and ventilation rates for 26 days in a naturally contained, warm-core eddy of the North Atlantic Ocean. This is the first study of the oceanic cycling of methyl bromide in a natural, contained system with a complete suite of supporting measurements of physical and chemical variables. Methyl bromide concentrations in the mixed layer ranged from 2.3 to 4.2 nmol m−3, degradation rates rang...


    Increased intake of chromium has been shown to lead to improvements in glucose, insulin, lipids, and related variables in studies involving humans, experimental and farm animals. However, the results are often variable depending not only upon the selection of subjects, but also dietary conditions a...

  16. Absorber performance of a water/lithium-bromide absorption chiller

    Xie Guozhen [Beijing University of Civil Engineering and Architecture, Beijing 100044 (China)], E-mail:; Sheng Guogang [Beijing University of Civil Engineering and Architecture, Beijing 100044 (China); Bansal, Pradeep Kumar [Department of Mechanical Engineering, The University of Auckland, Private Bag 92019 (New Zealand); Li, Guang [Beijing University of Civil Engineering and Architecture, Beijing 100044 (China)


    An absorber is one of the most important components of a lithium-bromide absorption chiller (LBAC) as its absorbing characteristics directly influence the performance of the whole chiller. It has been indicated that the absorbing efficiency and cooling capacity could be improved by increasing the solution concentration. In this paper, based on the mechanism of falling film absorption on horizontal tubes, the theoretical models of falling film absorption on horizontal tubes have been established. A series of programs used for computing the theoretical mathematical models, including simulation of LBAC cycle and falling film absorption, have been programmed. The models have been validated reasonably by the experimental data. The results show that the cooling capacity of the LBAC varies in parabola shape of curve with the solution concentration from 52.5% to 58.5%, and that the best coefficient of performance (COP) occurs at concentration of 57%. The investigation proposes the absorbing process of sub-steady thermodynamic equilibrium for the duality solution under increase absorbing pressure.

  17. Absorber performance of a water/lithium-bromide absorption chiller

    Xie, Guozhen; Sheng, Guogang; Li, Guang [Beijing University of Civil Engineering and Architecture, Beijing 100044 (China); Bansal, Pradeep Kumar [Department of Mechanical Engineering, The University of Auckland, Private Bag 92019 (New Zealand)


    An absorber is one of the most important components of a lithium-bromide absorption chiller (LBAC) as its absorbing characteristics directly influence the performance of the whole chiller. It has been indicated that the absorbing efficiency and cooling capacity could be improved by increasing the solution concentration. In this paper, based on the mechanism of falling film absorption on horizontal tubes, the theoretical models of falling film absorption on horizontal tubes have been established. A series of programs used for computing the theoretical mathematical models, including simulation of LBAC cycle and falling film absorption, have been programmed. The models have been validated reasonably by the experimental data. The results show that the cooling capacity of the LBAC varies in parabola shape of curve with the solution concentration from 52.5% to 58.5%, and that the best coefficient of performance (COP) occurs at concentration of 57%. The investigation proposes the absorbing process of sub-steady thermodynamic equilibrium for the duality solution under increase absorbing pressure. (author)

  18. Structural and electronic properties of Diisopropylammonium bromide molecular ferroelectric crystal

    Alsaad, A.; Qattan, I. A.; Ahmad, A. A.; Al-Aqtash, N.; Sabirianov, R. F.


    We report the results of ab-initio calculations based on Generalized Gradient Approximation (GGA) and hybrid functional (HSE06) of electronic band structure, density of states and partial density of states to get a deep insight into structural and electronic properties of P21 ferroelectric phase of Diisopropylammonium Bromide molecular crystal (DIPAB). We found that the optical band gap of the polar phase of DIPAB is ∼ 5 eV confirming it as a good dielectric. Examination of the density of states and partial density of states reveal that the valence band maximum is mainly composed of bromine 4p orbitals and the conduction band minimum is dominated by carbon 2p, carbon 2s, and nitrogen 2s orbitals. A unique aspect of P21 ferroelectric phase is the permanent dipole within the material. We found that P21 DIPAB has a spontaneous polarization of 22.64 consistent with recent findings which make it good candidate for the creation of ferroelectric tunneling junctions (FTJs) which have the potential to be used as memory devices.

  19. Chloride, bromide and iodide scintillators with europium doping

    Zhuravleva, Mariya; Yang, Kan


    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  20. 4-Bromophenacyl bromide specifically inhibits rhoptry secretion during Toxoplasma invasion.

    Ravindran, Sandeep; Lodoen, Melissa B; Verhelst, Steven H L; Bogyo, Matthew; Boothroyd, John C


    Toxoplasma gondii is a eukaryotic parasite of the phylum Apicomplexa that is able to infect a wide variety of host cells. During its active invasion process it secretes proteins from discrete secretory organelles: the micronemes, rhoptries and dense granules. Although a number of rhoptry proteins have been shown to be involved in important interactions with the host cell, very little is known about the mechanism of secretion of any Toxoplasma protein into the host cell. We used a chemical inhibitor of phospholipase A2s, 4-bromophenacyl bromide (4-BPB), to look at the role of such lipases in the secretion of Toxoplasma proteins. We found that 4-BPB was a potent inhibitor of rhoptry secretion in Toxoplasma invasion. This drug specifically blocked rhoptry secretion but not microneme secretion, thus effectively showing that the two processes can be de-coupled. It affected parasite motility and invasion, but not attachment or egress. Using propargyl- or azido-derivatives of the drug (so-called click chemistry derivatives) and a series of 4-BPB-resistant mutants, we found that the drug has a very large number of target proteins in the parasite that are involved in at least two key steps: invasion and intracellular growth. This potent compound, the modified "click-chemistry" forms of it, and the resistant mutants should serve as useful tools to further study the processes of Toxoplasma early invasion, in general, and rhoptry secretion, in particular. PMID:19956582

  1. Organomontmorillonites Modified with 2-Methacryloyloxy Ethyl Alkyl Dimethyl Ammonium Bromide

    WANG Jian-quan; WU Wen-hui


    Organomontmorillonites (organo-MMT) were synthesized by means of montmorillonites (MMT) modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide (MAAB) having different alkyl chain lengths as cationic surfactants through a cationic exchanging reaction, and were characterized by FTIR, TG, elemental analysis, and XRD. The microenvironment of the organic interlayer such as the orientation and arrangement of the alkyl chains of MAAB, as well as the properties of nanocomposite hydrogels, were also investigated. The amount of organic components absorbed on interlayer and the basal spacing of organo-MMT both increase with the increasing of alkyl length of MAAB. When carbon number of alkyl chain is in the region of 8 to 14, the alkyl chains between layers would adopt a disordered gauche conformation; while the carbon number is 16, an ordered all-trans conformation with a vertical orientation would be found together with the disordered gauche conformation according to the results of XRD and FTIR. Due to the difference of microenvironment of organic interlayer, the Young's moduli of the nanocomposite hydrogels increased as the alkyl chains of MAAB became longer.

  2. Evaluation of Alkali Bromide Salts for Potential Pyrochemical Applications

    Prabhat K. Tripathy; Steven D. Herrmann; Guy L. Fredrickson; Tedd E. Lister; Toni Y. Gutknecht


    Transient techniques were employed to study the electrochemical behavior, reduction mechanism and transport properties of REBr3 (RE - La, Nd and Gd) in pure LiBr, LiBr-KBr (eutectic) and LiBr-KBr-CsBr (eutectic) melts. Gd(III) showed a reversible single step soluble-insoluble exchange phenomenon in LiBr melt at 973K. Although La (III), Nd(III) and Gd(III) ions showed reversible behavior in eutectic LiBr-KBr melts, these ions showed a combination of temperature dependent reversible and pseudo-reversible behavior. While both La(III) and Gd(III) showed one step reduction, the reduction of Nd(III) was observed to be a two step process. La metal could be electrodeposited from the ternary electrolyte at a temperature of 673K. Various electrochemical measurements suggest that both binary and ternary bromide melts can potentially be used to electrodeposit high purity RE metals at comparatively lower operating temperatures.

  3. Accommodation coefficient of HOBr on deliquescent sodium bromide aerosol particles

    M. Wachsmuth


    Full Text Available Uptake of HOBr on sea salt aerosol, sea salt brine or ice is believed to be a key process providing a source of photolabile bromine (Br2 and sustaining ozone depletion cycles in the Arctic troposphere. In the present study, uptake of HOBr on sodium bromide (NaBr aerosol particles was investigated at an extremely low HOBr concentration of 300 cm-3 using the short-lived radioactive isotopes 83-86Br. Under these conditions, at maximum one HOBr molecule was taken up per particle. The rate of uptake was clearly limited by the mass accommodation coefficient, which was calculated to be 0.6 ± 0.2. This value is a factor of 10 larger than estimates used in earlier models. The atmospheric implications are discussed using the box model "MOCCA'', showing that the increase of the accommodation coefficient of HOBr by a factor of 10 only slightly affects net ozone loss, but significantly increases chlorine release.

  4. Improved spectrometric characteristics of thallium bromide nuclear radiation detectors

    Hitomi, K; Shoji, T; Suehiro, T; Hiratate, Y


    Thallium bromide (TlBr) is a compound semiconductor with a high atomic number and wide band gap. In this study, nuclear radiation detectors have been fabricated from the TlBr crystals. The TlBr crystals were grown by the horizontal travelling molten zone (TMZ) method using the materials purified by many pass zone refining. The crystals were characterized by measuring the resistivity, the mobility-lifetime (mu tau) product and the energy required to create an electron-hole pair (the epsilon value). Improved energy resolution has been obtained by the TlBr radiation detectors. At room temperature the full-width at half-maximum (FWHM) for the 59.5, 122 and 662 keV gamma-ray photo peak obtained from the detectors were 3.3, 8.8 and 29.5 keV, respectively. By comparing the saturated peak position of the TlBr detector with that of the CdTe detector, the epsilon value has been estimated to be about 5.85 eV for the TlBr crystal.

  5. Water-lithium bromide double-effect absorption cooling analysis

    Vliet, G.C.; Lawson, M.B.; Lithgow, R.A.


    A numerical model was developed for the transient simulation of the double-effect, water-lithium bromide absorption cooling machine, and the use of the model to determine the effect of the various design and input variables on the absorption unit performance. The performance parameters considered were coefficient of performance and cooling capacity. The sensitivity analysis was performed by selecting a nominal condition and determining performance sensitivity for each variable with others held constant. The variables considered in the study include source hot water, cooling water, and chilled water temperatures; source hot water, cooling water, and chilled water flow rates; solution circulation rate; heat exchanger areas; pressure drop between evaporator and absorber; solution pump characteristics; and refrigerant flow control methods. The performance sensitivity study indicated in particular that the distribution of heat exchanger area among the various (seven) heat exchange components is a very-important design consideration. Moreover, it indicated that the method of flow control of the first effect refrigerant vapor through the second effect is a critical design feature when absorption units operate over a significant range of cooling capacity. The model was used to predict the performance of the Trane absorption unit with fairly good accuracy.

  6. Nanocapsules of perfluorooctyl bromide for theranostics: from formulation to targeting

    Diou, O.; Fattal, E.; Payen, T.; Bridal, S. L.; Valette, J.; Tsapis, N.


    The need to detect cancer at its early stages, as well as, to deliver chemotherapy to targeted site motivates many researchers to build theranostic platforms which combine diagnostic and therapy. Among imaging modalities, ultrasonography and Magnetic Resonance Imaging (MRI) are widely available, non invasive and complement each other. Both techniques often require the use of contrast agents. We have developed nanocapsules of perfluorooctyl bromide as dual contrast agent for both imaging modalities. The soft, amorphous polymer shell provides echogenicity, while the high-density perfluorinated liquid core allows detection by 19F MRI. We have used a shell of poly(lactide-co-glycolide) (PLGA) since this polymer is biodegradable, biocompatible and can be loaded with drugs. These capsules were shown to be efficient in vitro as contrast agents for both 19F MRI and ultrasonography. In addition, for in vivo applications a poly(ethyleneglycol) (PEG) coating promotes stability and prolonged circulation. Being stealth, nanocapsule can accumulate passively into implanted tumors by the EPR effect. We will present nanocapsule formulation and characterization, and will show promising in vivo results obtained for both ultrasonography and 19F MRI.

  7. Chromium and Polyphenols From Cinnamon Improve Insulin Sensitivity

    Naturally occurring compounds that have been shown to improve insulin sensitivity include chromium and polyphenols found in cinnamon. These compounds also have similar effects on insulin signaling and glucose control. The signs of chromium deficiency are similar to those for the metabolic syndrome ...

  8. IRIS Toxicological Review of Hexavalent Chromium (2010 External Review Draft)

    [UPDATE] New Schedule for IRIS Hexavalent Chromium Assessment In Feb 2012, EPA developed a new schedule for completing the IRIS hexavalent chromium assessment. Based on the recommendations of the external peer review panel, which met in May 2011 to review the dra...

  9. Composition and structure of plasma sprayed chromium steel powders

    Schneeweiss, O.; Voleník, Karel; Kolman, Blahoslav Jan

    Praha, 2005, s. 105-111. ISBN 1899072 18 7. [EURO Powder Metallurgy Congress & Exhibition. Prague (CZ), 02.10.2005-05.10.2005] Institutional research plan: CEZ:AV0Z20430508 Keywords : chromium steel * plasma spraying * chromium depletion * Mössbauer spectroscopy Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  10. Safety, absorption, and antioxidant effects of chromium histidine

    Supplemental chromium has been shown to be involved in the alleviation of the metabolic syndrome, glucose intolerance, polycystic ovary syndrome, depression, excess body fat, and gestational, steroid-induced, and type 2 diabetes. Chromium amino acid complexes that contained histidine displayed cons...