WorldWideScience

Sample records for antimonates

  1. The Studies of A New Type of Crystalline Antimonic Acid

    Institute of Scientific and Technical Information of China (English)

    LIUXiaozhen; ZHOUJiayin; 等

    1993-01-01

    A new type of crystalline antimonic acid Sb2O5·3H2O was synthesized.The composition,crystal structure,the equilibrium distribution coefficients for sodium and potassium ions and the ion-exchange capacity of this exchanger were determined.With this exchanger,sodium inos were removed from potassium chloride,and the content of sodium chloride was reduced from 3.24% to 0.02%.Compared with other ion-exchange materials,the crystalline antimonic acid gives and unusual selectivity for potassium and sodium ions. The different compositions and properties of antimonic acid exchangers are obtained through different preparing conditions and its crystalline formula of Sb2O5·4H2O(C-SbA1) is currently accepted.This paper reports a new type of crystalline antimonic acid-Sb2O5·3H2O(C-SbA2),synthesized by an improved Kuzin′s method.Sodium ions are removed from potassium chloride with C-SbA2.The exchange efficiency is better than that of C-SbA1.

  2. Abiotic Reduction of Selenite and Antimonate Under Controlled Oxygen Conditions

    Science.gov (United States)

    Belzile, N.; Truong, H. T.; Polack, R.; Chen, Y.

    2008-12-01

    Laboratory and field studies have reported the oxidation of elemental Se to selenite or selenate or that of antimonite to antimonate but the reduction studies of the two elements, especially in absence of bacteria are more scarce. We have performed experiments on the abiotic reduction of Se(IV) and Sb(V) under controlled oxygen conditions in presence of naturally-encountered reducing agents such as Fe(II) and dissolved sulfide. In the case of selenite, the reduction by ferrous iron is barely detectable at very low concentrations of oxygen. However, at concentrations of 200 ± 50 ppmv in the controlled atmosphere glove box, more iron oxide particles were formed at a higher initial Fe(II) concentration in the system and with time. In the pellets collected after filtration, a significant amount of Se(0) was found. Our field geochemical studies on Se also showed the same phenomenon, i.e. a higher level of Se(0) in lake sediments was accompanied by a higher presence of iron oxides. In the case of antimony, the reduction of Sb(V) by dissolved sulfide was extensive and far more rapid at more acidic pH values. Half lives for Sb(V) in the presence of excess dissolved sulfide at pH values of 5 to 7 were calculated and the reaction was found to be first order with respect to all three of [Sb(V)], [dissolved sulfide] and [H+]. Metastibnite precipitated after reduction of Sb(V) in working experimental samples at buffered pH of 5 and 6. The oxidation product of dissolved sulfide was identified as elemental sulfur. This study has demonstrated the ability of dissolved sulfide to reduce Sb(V) under a variety of environmentally relevant concentrations and conditions.

  3. Synthesis and characterization of titanium vanadate and vanadium antimonate and their use in treatment of some toxic waste

    International Nuclear Information System (INIS)

    Ion exchangers are insoluble solid materials, which carry exchangeable cations or anions. When the ion exchanger is in contact with an electrolyte solution, these ions are exchanged with an equivalent amount of other ions of the same sign .Synthetic inorganic ion exchangers possess good ion-exchange capacity, high chemical and radiation stabilities, reproducibility and selectivity for heavy metals. These materials were characterized using X-ray (XRD and XRF), IR, TGA-DTA and total elemental analysis studies. On the basis of distribution studies, titanium vanadate was highly selective for Cs(I) while vanadium antimonate was selective for Cu2+ ions . Thermodynamic parameters (i.e. ΔGo, ΔSo and ΔHo) have also been calculated for the adsorption of Cs+, Cd2+, Cu2+ and Co2+ ions on titanium vanadate and vanadium antimonate showing that the overall adsorption process is spontaneous and endothermic. The mechanism of diffusion of Co2+, Cu2+, Cd2+ and Cs+ in the H -form of titanium vanadate and vanadium antimonate cation exchanger was studied as a function of particle size, concentration of the exchanging ions, reaction temperature, drying temperature. The exchange rate was controlled by particle diffusion mechanism as a limited batch technique and is confirmed from straight lines of B versus 1/r2 plots. The values of diffusion coefficients, activation energy and entropy of activation were calculated and their significance was discussed. The data obtained have been compared with that reported for other organic and inorganic exchangers. Exchange isotherms for H+/Co2+, H+/Cu2+, H+/Cd2+ and H+/Cs+ were determined at 25, 45 and 60±1 degree C. These isotherms showed that Co2+,Cu2+, Cd2+ and Cs+ are chemically adsorbed. Moreover, the values of thermodynamic parameters were determined and the overall adsorption processes were found spontaneous and endothermic. Finally, removal of the above mentioned cations on titanium vanadate and vanadium antimonate in column was performed.

  4. Theoretical study of the influence of cation vacancies on the catalytic properties of vanadium antimonate

    Energy Technology Data Exchange (ETDEWEB)

    Messina, S. [Laboratorio de Procesos Cataliticos, Departamento de Ingenieria Quimica, FIUBA, Pabellon de Industrias, Ciudad Universitaria, (1428) Capital Federal (Argentina); Juan, A. [Departamento de Fisica, UNS, Av. Alem 1253, (8000) Bahia Blanca (Argentina)], E-mail: cajuan@uns.edu.ar; Larrondo, S.; Irigoyen, B.; Amadeo, N. [Laboratorio de Procesos Cataliticos, Departamento de Ingenieria Quimica, FIUBA, Pabellon de Industrias, Ciudad Universitaria, (1428) Capital Federal (Argentina)

    2008-07-15

    We have theoretically studied the influence of antimony and vanadium cation vacancies in the electronic structure and reactivity of vanadium antimonate, using molecular orbital methods. From the analysis of the electronic properties of the VSbO{sub 4} crystal structure, we can infer that both antimony and vanadium vacancies increase the oxidation state of closer V cations. This would indicate that, in the rutile-type VSbO{sub 4} phase the Sb and V cations defects stabilize the V in a higher oxidation state (V{sup 4+}). Calculations of the adsorption energy for different toluene adsorption geometries on the VSbO{sub 4}(1 1 0) surface have also been performed. The oxidation state of Sb, V and O atoms and the overlap population of metal-oxygen bonds have been evaluated. Our results indicate that the cation defects influence in the toluene adsorption reactions is slight. We have computed different alternatives for the reoxidation of the VSbO{sub 4}(1 1 0) surface active sites which were reduced during the oxygenated products formation. These calculations indicate that the V cations in higher oxidation state (V{sup 4+}) are the species, which preferentially incorporate lattice oxygen to the reduced Sb cations. Thus, the cation defects would stabilize the V{sup 4+} species in the VSbO{sub 4} structure, determining its ability to provide lattice oxygen as a reactant.

  5. A new strontium antimonate{sup III} Sr{sub 5}Sb{sub 22}O{sub 38}: Synthesis, crystal structure and characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Lei, E-mail: lgeng.cn@gmail.com [Department of Physics and Electronic Information, Huaibei Normal University, Huaibei, Anhui 235000 (China); Meng, Chang-Yu [Department of Chemistry and Materials, Yulin Normal University, Yulin, Guangxi 537000 (China); Lin, Chen-Sheng [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Cheng, Wen-Dan, E-mail: cwd@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2013-07-15

    A new strontium antimonate{sup III}, Sr{sub 5}Sb{sub 22}O{sub 38}, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. It crystallizes in the P2{sub 1}/n space group of the monoclinic system with a=11.739(9) Å, b=12.014(10) Å, c=16.412(13) Å, β=91.460(8)°, V=2314.0(3) Å{sup 3}. The crystal structure is built of seven trigonal–pyramidal SbO{sub 3} and four sphenoid SbO{sub 4} polyhedra which are connected through sharing corner-oxygen atoms to form the complex three-dimensional {sub ∞}{sup 3}[Sb{sub 22}O{sub 38}]{sup 10−} anionic network with two different intersectant tunnels along the [111-bar ] and [11-bar 1-bar ] directions accommodating the electric charge balanced Sr{sup 2+} cations. First-principles electronic structure calculations based on the density functional theory (DFT) and the UV–vis diffuse reflectance spectroscopy measurements both indicate that the compound belongs to a direct band insulator with an optical gap value of 3.3 eV. - Graphical abstract: The 2D Sb–O slabs are stacked through sharing oxygen atoms to form the 3D network structure of the new strontium antimonate{sup III} Sr{sub 5}Sb{sub 22}O{sub 38}. - Highlights: • A new strontium antimonate{sup III}, Sr{sub 5}Sb{sub 22}O{sub 38}, has been hydrothermally synthesized. • The single crystal structure was determined by X-ray diffraction. • The powder XRD and UV–vis absorption spectroscopy were studied. • Theoretical studies interpret the relationships between optical absorption and crystal structure.

  6. Crystallization and preliminary crystallographic characterization of LmACR2, an arsenate/antimonate reductase from Leishmania major

    Energy Technology Data Exchange (ETDEWEB)

    Bisacchi, Davide [Bioinformatics and Structural Proteomics, IST-National Cancer Research Institute, Genova (Italy); Zhou, Yao; Rosen, Barry P.; Mukhopadhyay, Rita [Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan (United States); Bordo, Domenico, E-mail: domenico.bordo@istge.it [Bioinformatics and Structural Proteomics, IST-National Cancer Research Institute, Genova (Italy)

    2006-10-01

    LmACR2 from L. major is the first rhodanese-like enzyme directly involved in the reduction of arsenate and antimonate to be crystallized. Diffraction data have been collected to 1.99 Å resolution using synchrotron X-rays. Arsenic is present in the biosphere owing either to the presence of pesticides and herbicides used in agricultural and industrial activities or to leaching from geological formations. The health effects of prolonged exposure to arsenic can be devastating and may lead to various forms of cancer. Antimony(V), which is chemically very similar to arsenic, is used instead in the treatment of leishmaniasis, an infection caused by the protozoan parasite Leishmania sp.; the reduction of pentavalent antimony contained in the drug Pentostam to the active trivalent form arises from the presence in the Leishmania genome of a gene, LmACR2, coding for the protein LmACR2 (14.5 kDa, 127 amino acids) that displays weak but significant sequence similarity to the catalytic domain of Cdc25 phosphatase and to rhodanese enzymes. For structural characterization, LmACR2 was overexpressed, purified to homogeneity and crystallized in a trigonal space group (P321 or P3{sub 1}21/P3{sub 2}21). The protein crystallized in two distinct trigonal crystal forms, with unit-cell parameters a = b = 111.0, c = 86.1 Å and a = b = 111.0, c = 175.6 Å, respectively. At a synchrotron beamline, the diffraction pattern extended to a resolution limit of 1.99 Å.

  7. Removal of some heavy metals from industrial waste water using polyacrylamide ferric antimonate as new ion exchange material

    International Nuclear Information System (INIS)

    Composite ion exchangers consist of one or more ion exchangers combined with another material, which can be inorganic or organic and may it be an ion exchanger. The reason for manufacturing a composite material is to produce a granular material, with sufficient strength for column use, from ion exchangers that do not form, or only form weak, granules themselves. Attempts in this study are focused to prepare composite ion exchangers for treatment of wastewater. Heavy metals when present in water in concentrations exceeding the permitted limits are injurious to the health. Hence, it is very important to treat such waters to remove the metal ions present before it is supplied for any useful purpose. Therefore, many investigations have studied to develop more effective process to treat such waste stream. Ion-exchange has been widely adopted in heavy metal containing wastewater and most of the ion-exchangers (i.e. ion-exchange media) currently being used are commercially mass-produced organic resins.Therefore, the main aim of this work is directed to find the optimum conditions for removal of some heavy metals from industrial waste water.1-Preparation of polyacrylamide ferric antimonate composite.2-Characterization of the prepared exchanger using IR spectra, X-ray diffraction pattern, DTA and TG analyses.3-Chemical stability, capacity and equilibrium measurements will be determined on the materials using at different conditions (ph heating temperature and reaction temperature).4-Kinetic studies of some heavy metals.5-Ion exchange isotherm.6-Breakthrough curves for removal of the investigated metal ions on the prepared exchanger under certain condition.

  8. Single step hydrothermal based synthesis of M(II)Sb2O6 (M = Cd and Zn) type antimonates and their photocatalytic properties

    Indian Academy of Sciences (India)

    Jyoti Singh; Neha Bhardwaj; S Uma

    2013-04-01

    Experiments involving single step hydrothermal reactions of the divalent metal (Zn2+, Cd2+, Pb2+, Cu2+, Ni2+ and Mn2+) salts with ilmenite NaSbO3 yielded pure divalent antimonates in the case of CdSb2O6 crystallizing in the PbSb2O6 type structure and ZnSb2O6 crystallizing in the trirutile structure type. In the case of Pb2+, Cu2+, Ni2+ and Mn2+ divalent cations, phase pure product could not be obtained. The obtained powders were characterized by powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and UVvisible diffuse reflectance spectroscopy. The oxide powders obtained possessed lower crystallite size as compared to their solid-state synthesized counterparts. This was evident from the broadening of the powder X-ray diffraction peaks. The antimonates were photocatalytically active for the decomposition of methylene blue (MB) dye under UV light irradiation.

  9. Ateşli silah atış artıklarında voltametrik sıyırma yötemleri ile antimon, baryum ve kurşunun tayini

    OpenAIRE

    ERDEN, Sevcan

    2010-01-01

        Bu çalışmada, atış artıklarında antimon, baryum ve kurşunun tayini için diferansiyel puls adsorptif sıyırma (DPAdS) ve kare dalga adsorptif sıyırma (KDAdS) voltametri yöntemleri geliştirildi. Bu yöntemlerde kurşun(II) ve antimon(III)’ün rezorsinol ve katekol; baryumun diizooktilditiyofosfinik asit ile oluşturduğu kompleksin asılı cıva damla elektrot yüzeyinde adsorplanmasından yararlanıldı. Her bir metal iyonu için optimum deney koşulları (pH, biriktirm...

  10. Biomonitoring of persons living in areas with high concentrations of mercury, arsenic and antimony in soil. Goals and methods; Biomonitoring-Untersuchung bei Personen in Wohngebieten mit erhoehten Bodenwerten an Quecksilber, Arsen und Antimon. Vorstellung und Studiendesign

    Energy Technology Data Exchange (ETDEWEB)

    Gebel, T. [Goettingen Univ. (Germany). Abt. Allgemeine Hygiene; Schaefer, J. [Mainz Univ. (Germany). Inst. fuer Medizinische Mikrobiologie und Hygiene; Beuermann, I. [Mainz Univ. (Germany). Inst. fuer Medizinische Mikrobiologie und Hygiene; Platen, H. von [Mainz Univ. (Germany). Inst. fuer Geowissenschaften; Dunkelberg, H. [Goettingen Univ. (Germany). Abt. Allgemeine Hygiene

    1995-07-01

    In the northern part of palatinate country in Germany (Nordpfaelzer Bergland; Rheinland-Pfalz) intense mercury activity had been situated beginning in the 15th century extending partly up into the 20th century. Nowadays in many cases former dump grounds of rubble caused by the mercury mining activities are used for agricultural and housing purposes. In soil material of these areas the natural background contents up to strongly elevated levels were found for mercury, arsenic and antimony. In the housing area soil concentrations (per dry matter) of less than 0,5 mg/kg up to 1364 mg/kg mercury, less than 2 mg/kg up to 605 mg/kg arsenic and less than 0,5 mg/kg up to 776 mg/kg antimony were detected. Mercury, arsenic and antimony are strongly bound to be ore in sulfidic forms of cinnabar or fahlore (gray copper) causing a bad availability. The concentration variance of the detected element levels is immense even relating to little spaces because of an inhomogenous distribution of the rubble; highly contaminated grounds can be found beneath not contaminated ground. A biomonitoring study is presented in which 219 exposed residents are involved. They are examined concerning a possible incorporation of the elements mentioned above. The proceeding of the study, the way of data collection, and the amnestical approach are discussed. This study ist compared to similar studies. (orig.) [Deutsch] Im Nordpfaelzer Bergland wurde vom 15. bis teilweise ins 20. Jahrhundert intensiv Quecksilberbergbau betrieben. Vielfach befinden sich landwirtschaftlich genutzte Flaechen und Wohngebiete auf oder neben Abraumhalden des ehemaligen Quecksilberbergbaus. In diesen Regionen fand man im Boden fuer das Schwermetall Quecksilber und die metalloide Arsen und Antimon von den natuerlichen Hintergrundkonzentrationen bis hin zu stark erhoehten Werten. In Wohngebieten waren dies bei Quecksilber weniger als 0,5 mg/kg Boden (Trockensubstanz) bis zu 1364 mg/kg, bei Arsen weniger als 2 mg/kg bis zu 605 mg

  11. RESEARCH ON MECHANISM OF LEACHING ANTIMONOUS OXIDE BY AQUEOUS SOLUTION OF SODIUM HYDROXIDE AND GLYCERIN%NaOH、甘油的水溶液浸出三氧化二锑的机理研究

    Institute of Scientific and Technical Information of China (English)

    潘朝群; 邓先和; 宾万达; 杨天足

    2001-01-01

    Antimonous oxide can be dissolved in aqueous solution of sodium hydroxide and glycerin and the new product is sodium antimonite containing glycerin.The solution is stable under a certain concentration of sodium hydroxide.The mechanism of the reaction and the stability of sodium antimonite containing glycerin solution have been studied.%NaOH、甘油或木糖醇的水溶液浸出锑氧粉得到双金属醇盐,溶液在一定的碱性条件下能保持稳定;本文对NaOH、甘油的水溶液浸出三氧化二锑生成甘油亚锑酸钠的机理及其稳定性作了一系列的研究。

  12. Synthesis and characterization of arsenate antimonic acid AAAc(1 : 1)

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-wen; CHEN Qi-yuan; YIN Zhou-lan; ZHANG Ping-min; WANG Yu-wen

    2005-01-01

    The AAAc(1 : 1) was synthesized in water by As2O3 and Sb2O3 with molar ratio of 1 : 1: AAAc(1 : 1)was characterized by Raman, IR, TG/DTG, DSC, XPS and XRD. The results show that there are four peaks to vsof As-OH, As-O-Sb, Sb-OH and Sb-O-Sb in Raman spectra of AAAc(1 : 1) at 100 - 1 000 cm-1. The solution of AAAc(1 : 1) was also titrated with KOH solution. The titration results show that AAAc(1 : 1) is a hexabasic acid with dissociation constants of k1 = 3.62 × 10-2 , k2 = 3.05 × 10-3 , k3 = 6. 43 × 10-6 , k4 = 9. 78 × 10-8 ,k5 = 1.32 × 10-11 , k6 =3.87 × 10-12. AAAc(1 : 1) has a good solubility and stability in water, its solid obtained by free volatilizing water from its solution under air at ambient temperature is amorphous. Chemical and thermal analyture of AsO ( OH )2-OH-Sb ( OH )4-O-Sb ( OH )4-OH-AsO ( OH )2 or As ( OH )3-O-Sb(OH)4-O-Sb(OH)4-O-As(OH)3 (isomerism) through experimental determination and geometry optimization.

  13. Niedervalente Bismut-Organyle, chirale Stibane und Antimon-Analoge des Betains und Cholins

    OpenAIRE

    Balazs Lucia

    2003-01-01

    The cyclobismuthanes (RBi):sub:n:/sub:, [R = 2-(Me:sub:2:/sub:NCH:sub:2:/sub:)C:sub:6:/sub:H:sub:4:/sub:, n = 3 (:b:1a:/b:), 4 (:b:1b:/b:)] were synthesized by reduction of RBiCl:sub:2:/sub: with Na in liquid ammonia or by reaction of R:sub:2:/sub:BiCl with LiAlH:sub:4:/sub: in ether. The reaction of :b:1a / b:/b: with W(CO):sub:5:/sub:THF (THF = tetrahydrofuran) gives the bismuthinidene complex RBi[W(CO):sub:5:/sub:]:sub:2:/sub: (:b:2:/b:). R:sub:2:/sub:BiCl reacts with Mg in THF to give R:s...

  14. CO and C3H8 Sensitivity Behavior of Zinc Antimonate Prepared by a Microwave-Assisted Solution Method

    Directory of Open Access Journals (Sweden)

    Héctor Guillen-Bonilla

    2015-01-01

    Full Text Available ZnSb2O6 has been synthesized by a microwave-assisted solution method in order to test its possible application as a gas sensor. Zinc nitrate, antimony trichloride, and ethylenediamine were used as precursors and deionized water as solvent. Microwave radiation, with a power of ~350 W, was applied for solvent evaporation. The thermal decomposition of the precursors leads to the formation of ZnSb2O6 at 600°C. This oxide crystallized in a tetragonal structure with cell parameters a=4.66 Å, c=9.26 Å and space group P42/mnm. Microwires and microrods formed by nanocrystals were observed by means of scanning and transmission electron microscopies (SEM and TEM, resp.. Pellets of the oxide were tested as gas sensors in flowing atmospheres of carbon monoxide (CO and propane (C3H8. Sensitivity increased with the gas concentration (0–300 ppm and working temperatures (ambient, 150 and 250°C increase. The results indicate high sensitivity of ZnSb2O6 in both gases at different concentrations and operating temperatures.

  15. CO and C3H8 Sensitivity Behavior of Zinc Antimonate Prepared by a Microwave-Assisted Solution Method

    OpenAIRE

    Héctor Guillen-Bonilla; Verónica-M. Rodríguez-Betancourtt; José-Trinidad Guillén-Bonilla; Juan Reyes-Gómez; Lorenzo Gildo-Ortiz; Martín Flores-Martínez; Olvera-Amador, M. de la L.; Jaime Santoyo-Salazar

    2015-01-01

    ZnSb2O6 has been synthesized by a microwave-assisted solution method in order to test its possible application as a gas sensor. Zinc nitrate, antimony trichloride, and ethylenediamine were used as precursors and deionized water as solvent. Microwave radiation, with a power of ~350 W, was applied for solvent evaporation. The thermal decomposition of the precursors leads to the formation of ZnSb2O6 at 600°C. This oxide crystallized in a tetragonal structure with cell parameters a=4.66 Å, c=9.26...

  16. Synthesis and characterization of rare-earth barium antimonates, a new group of complex perovskites suitable as substrates for YBa2Cu3O7-δ films

    International Nuclear Information System (INIS)

    A new group of complex perovskites, REBa2SbO6 (where RE = Pr, Sm, and Gd), have been synthesized and sintered as single phase materials by the solid state reaction method. These materials are found to be isostructural and to have a complex cubic perovskite structure. X-ray diffraction and resistivity measurements have shown that there is no detectable chemical reaction between YBa2Cu3O7-δ and REBa2SbO6 even under severe heat treatment at 950 degrees C and that the addition of REBa2SbO6 up to 20 vol% in YBa2Cu3O7-δ shows no detrimental effect on the superconducting properties of YBa2Cu3O7-δ. The dielectric constant and loss factor values of the sintered REBa2SbO6 materials are in a range suitable for their use as substrates for microwave applications. Thick films of YBa2Cu3O7-δ fabricated on polycrystalline REBa2SbO6 substrates give superconducting zero resistivity transition temperature Tc(0) = 92 K, indicating the suitability of these materials as substrates for YBa2Cu3O7-δ films

  17. Oral bioavailability of arsenic, antimony and a selection of metals in ashes; Oral biotillgaenglighet av arsenik, antimon och ett urval av metaller i askor

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Christel; Bendz, David; Jones, Celia

    2008-06-15

    In an earlier study, financed by Varmeforsk, 'Q4-238 Environmental guidelines for reuse of ash in civil engineering applications', the total content of arsenic and lead was shown to determine whether or not reuse of some of the ashes in construction work is feasible. The model used to calculate the guidelines uses the total concentration of metals to evaluate the health risks resulting from exposure to the ashes. The use of total concentration can lead to overly conservative risk assessments if a significant fraction of the total metal content is not bioavailable. Better precision in the risk assessment can be given by the use of the bioavailable fraction of arsenic and lead in the model. As a result, ashes which are rejected on the basis of total metal concentration may be acceptable for use in engineering construction when the assessment is based on the bioavailable fraction. The purpose of the study was to (i) compile information on the oral bioavailability of arsenic, antimony and a selection of metals in ashes and similar materials, and on in vitro methods for determination of oral bioavailability, and (ii) experimentally estimate oral bioavailability of arsenic, antimony and some metals in a selection of ashes by analysis of the gastrointestinal bioaccessibility of these elements. The investigated elements were antimony, arsenic, lead, cadmium, copper, chromium, nickel and zinc. In the literature study performed within the project a number of static and dynamic in vitro methods simulating gastrointestinal processes of contaminants were compiled. The methods include one or several segments, i.e. mouth, stomach and intestine. Among the compiled methods, the RIVM (Rijksinstituut voor volksgesundheid en milieu) in vitro method was used in the experimental part of the project. The advantages with the method was that: the method to a high degree mimicked the human gastrointestinal processes (the method included three segments mouth, stomach, and intestine); . the method was relatively simple; . the method could include an anaerobic step if needed; the method could include food; knowledge of the method existed in Sweden; and the method had been compared and evaluated in a scientific publication. In the experimental part of the study the bioaccessibility of antimony, arsenic, lead, cadmium, chromium, copper, nickel and zinc in seven different ashes at two different particle size fractions (<63 mum and <2 mm) was investigated. These fractions were chosen to represent voluntary (<2 mm) and involuntary (<63 mum) ingestion of ash. The investigated ashes were produced in different incineration plants and represented different categories, i.e. type of ash (fly ash or bottom ash), fuel and incinerator. In the experimental part the influence of total concentration of the elements on their bioaccessibility was also investigated, as well as the influence of particle size fraction on total content of the elements. The influence of type of ash on both bioaccessibility and total concentration of the specific elements was also investigated. The bioaccessible fraction of antimony, arsenic, cadmium, chromium, copper, lead, nickel and zinc in a selection of ashes showed a higher variation between the different elements than between the different ashes. With the exception of arsenic in two of the investigated ashes, the bioaccessible concentration was substantially less than the total concentration of all elements in all ashes. The bioaccessible fraction of arsenic was high both in fly ashes (>85%) and in bottom ashes (40-85%). The bioaccessible fraction of lead was also relatively high and varied between 14 and 60% in the different ashes. Cadmium also had a high bioaccessible fraction which varied between 50-75% in the investigated ashes. The bioaccessible fraction of chromium was much smaller compared to the bioaccessible fraction of the other elements, and was with two exceptions less than 12%. The bioaccessible fraction of copper was relatively high and varied between 20 and 70% in the different ashes. In this s

  18. Speciation of eight arsenic compounds in human urine by high performance liquid chromatography with inductively coupled plasma mass spectrometric detection using antimonate for internal chromatographic standardization

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pritzl, G.; Hansen, S. H.

    1993-01-01

    Four anionic and four cationic arsenic compounds in urine were separated by anion- and cation-exchange high-performance liquid chromatography and detected by inductively coupled plasma mass spectrometry (ICP-MS) at m/z 75. The species were the anions arsenite, arsenate, monomethylarsonate...... to arsenate in urine but was stable after at least 4-fold dilution of the urine with water. Arsenite was unstable in both urine samples and standard mixtures when diluted with the basic (pH 10.3) mobile phase used for anion chromatography. This could not be prevented by adding ascorbic acid as antioxidant...

  19. Oral bioavailability of arsenic, antimony and a selection of metals in ashes; Oral biotillgaenglighet av arsenik, antimon och ett urval av metaller i askor

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Christel; Bendz, David; Jones, Celia

    2008-06-15

    In an earlier study, financed by Varmeforsk, 'Q4-238 Environmental guidelines for reuse of ash in civil engineering applications', the total content of arsenic and lead was shown to determine whether or not reuse of some of the ashes in construction work is feasible. The model used to calculate the guidelines uses the total concentration of metals to evaluate the health risks resulting from exposure to the ashes. The use of total concentration can lead to overly conservative risk assessments if a significant fraction of the total metal content is not bioavailable. Better precision in the risk assessment can be given by the use of the bioavailable fraction of arsenic and lead in the model. As a result, ashes which are rejected on the basis of total metal concentration may be acceptable for use in engineering construction when the assessment is based on the bioavailable fraction. The purpose of the study was to (i) compile information on the oral bioavailability of arsenic, antimony and a selection of metals in ashes and similar materials, and on in vitro methods for determination of oral bioavailability, and (ii) experimentally estimate oral bioavailability of arsenic, antimony and some metals in a selection of ashes by analysis of the gastrointestinal bioaccessibility of these elements. The investigated elements were antimony, arsenic, lead, cadmium, copper, chromium, nickel and zinc. In the literature study performed within the project a number of static and dynamic in vitro methods simulating gastrointestinal processes of contaminants were compiled. The methods include one or several segments, i.e. mouth, stomach and intestine. Among the compiled methods, the RIVM (Rijksinstituut voor volksgesundheid en milieu) in vitro method was used in the experimental part of the project. The advantages with the method was that: the method to a high degree mimicked the human gastrointestinal processes (the method included three segments mouth, stomach, and intestine); . the method was relatively simple; . the method could include an anaerobic step if needed; the method could include food; knowledge of the method existed in Sweden; and the method had been compared and evaluated in a scientific publication. In the experimental part of the study the bioaccessibility of antimony, arsenic, lead, cadmium, chromium, copper, nickel and zinc in seven different ashes at two different particle size fractions (<63 mum and <2 mm) was investigated. These fractions were chosen to represent voluntary (<2 mm) and involuntary (<63 mum) ingestion of ash. The investigated ashes were produced in different incineration plants and represented different categories, i.e. type of ash (fly ash or bottom ash), fuel and incinerator. In the experimental part the influence of total concentration of the elements on their bioaccessibility was also investigated, as well as the influence of particle size fraction on total content of the elements. The influence of type of ash on both bioaccessibility and total concentration of the specific elements was also investigated. The bioaccessible fraction of antimony, arsenic, cadmium, chromium, copper, lead, nickel and zinc in a selection of ashes showed a higher variation between the different elements than between the different ashes. With the exception of arsenic in two of the investigated ashes, the bioaccessible concentration was substantially less than the total concentration of all elements in all ashes. The bioaccessible fraction of arsenic was high both in fly ashes (>85%) and in bottom ashes (40-85%). The bioaccessible fraction of lead was also relatively high and varied between 14 and 60% in the different ashes. Cadmium also had a high bioaccessible fraction which varied between 50-75% in the investigated ashes. The bioaccessible fraction of chromium was much smaller compared to the bioaccessible fraction of the other elements, and was with two exceptions less than 12%. The bioaccessible fraction of copper was relatively high and varied between 20 and 70% in the different ashes. In this study, particle size fraction only had an effect on the bioaccessible fraction of arsenic, chromium, and copper. For these elements, bioaccessibility was higher in the smaller particle size fraction representing involuntary ingestion. Particle size fraction also had an effect on the total concentration of cadmium, nickel, antimony and zinc, with higher total concentrations in the smaller particle size fraction. Total concentration only had an effect on the bioaccessible fraction of arsenic, copper and lead, with higher bioaccessible fractions at lower total concentrations. The type of ash had an influence on the bioaccessible fraction of arsenic, cadmium, chromium and antimony, with a higher bioaccessible fraction of arsenic, chromium and antimony in fly ashes compared to in bottom ashes, and a higher bioaccessible fraction of cadmium in bottom ashes compared to in fly ashes.

  20. Zigzag antiferromagnetic quantum ground state in monoclinic honeycomb lattice antimonates A3N i2Sb O6(A =Li ,Na )

    Science.gov (United States)

    Zvereva, E. A.; Stratan, M. I.; Ovchenkov, Y. A.; Nalbandyan, V. B.; Lin, J.-Y.; Vavilova, E. L.; Iakovleva, M. F.; Abdel-Hafiez, M.; Silhanek, A. V.; Chen, X.-J.; Stroppa, A.; Picozzi, S.; Jeschke, H. O.; Valentí, R.; Vasiliev, A. N.

    2015-10-01

    We present a comprehensive experimental and theoretical study of the electronic and magnetic properties of two quasi-two-dimensional (2D) honeycomb lattice monoclinic compounds A3N i2Sb O6(A =Li ,Na ) . Magnetic susceptibility and specific heat data are consistent with the onset of antiferromagnetic long-range order with Néel temperatures of ˜14 and 16 K for L i3N i2Sb O6 and N a3N i2Sb O6 , respectively. The effective magnetic moments of 4.3 μB/f .u .(L i3N i2Sb O6 ) and 4.4 μB/f .u .(N a3N i2Sb O6 ) , where f.u. is formula units, indicate that N i2 + is in a high-spin configuration (S =1 ). The temperature dependence of the inverse magnetic susceptibility follows the Curie-Weiss law in the high-temperature region and shows positive values of the Weiss temperature, ˜8 K (L i3N i2Sb O6 ) and ˜12 K (N a3N i2Sb O6 ), pointing to the presence of nonnegligible ferromagnetic interactions, although the system orders antiferromagnetically at low temperatures. In addition, the magnetization curves reveal a field-induced (spin-flop type) transition below TN that can be related to the magnetocrystalline anisotropy in these systems. These observations are in agreement with density functional theory calculations, which show that both antiferromagnetic and ferromagnetic intralayer spin exchange couplings between N i2 + ions are present in the honeycomb planes, supporting a zigzag antiferromagnetic ground state. Based on our experimental measurements and theoretical calculations, we propose magnetic phase diagrams for the two compounds.

  1. Leachability of antimony from energy ashes. Total contents, leachability and remedial suggestions; Lakning av antimon fraan energiaskor. Totalhalter, lakbarhet samt foerslag till aatgaerder

    Energy Technology Data Exchange (ETDEWEB)

    Baeckstroem, Mattias [Oerebro Univ. (Sweden)

    2006-01-15

    In the current project total concentrations for antimony in 31 energy ashes have been compiled. The average concentration of antimony in boiler fly ash and grate boiler fly ash is 192 and 1,140 mg/kg, respectively. The corresponding antimony concentrations for boiler ashes and grate bottom ashes are 86,5 and 61,8 mg/kg, respectively. Multivariate calculations clearly pointed out waste as the major source for antimony in ashes. The difference between total antimony concentration in fly ash and bottom ash is greatest for grate boilers, in average 18 times higher in the fly ash. The difference for CFB/BFB-boilers is only slightly more than 2. However, based on amount, 75% of the total antimony inventory is recovered in the fly ashes for both CFB/BFB and grate boilers. Eleven (eight of which were bottom ashes) out of the 31 samples exceeded the guidelines for inert waste. It is clear that the higher ionic strength in the solutions from the fly ashes contribute to decrease the solubility for critical minerals retaining antimony. In addition, the fly ashes have considerably larger effective surface able to sorb trace elements. A clear and positive covariance was discovered between aluminium and antimony. Furthermore, it was noted that antimony showed no typical anionic behaviour despite the fact that it according to the geochemical calculations should be present as SbO{sub 3}{sup -}. At L/S 10, a maximum of 1% of the total antimony concentration is leached. This should be compared to chloride that had 94% of the total concentration leached at L/S 10. There was no correlation between the leached antimony concentrations and the total antimony concentrations. The sequential extractions also suggest a low leachability for antimony from the ashes. In average only 9,6% is released at pH 7, 7,3% at pH 5, 3,6% during reducing conditions and 3,2% during oxidising conditions. In total, only 24% of the total antimony concentrations is released during the four extraction steps. The remaining 76% is probably to be found in the silicate matrix. Through multivariate calculations (PCA and MLR) and geochemical calculations (PHREEQC) aluminium and sulphate have been identified as being important for antimony leaching from the ashes. It is thus likely that ettringite governs antimony leachability at alkaline pH. When ettringite is solubilized the leachability of antimony will be dependent on the presence of effective sorbents. To decrease the leachability of antimony from the ashes addition of sulphate solution to the ashes is suggested, to increase the stability of ettringite at alkaline pH. Below the pH-range where ettringite is stable addition of manganese solution would give a new effective sorbent for antimony in solution. It was also noted that all fly ashes with addition of activated carbon did not exceed any guide lines for antimony leaching.

  2. Selective propene oxidation on mixed metal oxide catalysts

    CERN Document Server

    James, D W

    2002-01-01

    Selective catalytic oxidation processes represent a large segment of the modern chemical industry and a major application of these is the selective partial oxidation of propene to produce acrolein. Mixed metal oxide catalysts are particularly effective in promoting this reaction, and the two primary candidates for the industrial process are based on iron antimonate and bismuth molybdate. Some debate exists in the literature regarding the operation of these materials and the roles of their catalytic components. In particular, iron antimonate catalysts containing excess antimony are known to be highly selective towards acrolein, and a variety of proposals for the enhanced selectivity of such materials have been given. The aim of this work was to provide a direct comparison between the behaviour of bismuth molybdate and iron antimonate catalysts, with additional emphasis being placed on the component single oxide phases of the latter. Studies were also extended to other antimonate-based catalysts, including coba...

  3. Ultrastructure of Gladiolus x hybridus root endodermis

    Directory of Open Access Journals (Sweden)

    Anna Rudzińska-Langwald

    2014-02-01

    Full Text Available Gladiolus.x hybridus Van Houtte roots had primary, secondary and tertiary endodermis depending on the distance from the root apex. Free calcium ions were localized with the method of Slocum and Roux (1982. Electron microscopic observations revealed that electron dense calcium antimonite deposits were localized in some endodermis cells. Endodermis cells situated above xylem elements were rich in calcium antimonate deposits in contrary to those situated above the phloem elements and passage cells. The cells rich in calcium ions were present both in endodermis 11 and III stage of development. Localization of calcium deposits was on plasma membrane and tonoplast. There were also numerous calcium antimonate deposits in vacuoles. Dictiosome's cisterns and Golgi derived vesicles show presence of calcium ions. Calcium rich endodermis cells had plastids with antimonate deposits present in their tylacoids lumen. Plasmode-smata looked the same in all endodermis cells, but those from calcium rich endodermis cells had calcium antimonate deposits in the lumen of plasmodesmata.

  4. Rediscovering ancient glass technologies through the examination of opacifier crystals

    Science.gov (United States)

    Lahlil, S.; Biron, I.; Galoisy, L.; Morin, G.

    2008-07-01

    The aim of the study is to understand how antimonate opacifying crystals were obtained throughout history. Two archaeological glass productions opacified with calcium and lead antimonates are studied in this paper, in order to rediscover ancient opaque glass technologies: Roman mosaic tesserae (1st cent. B.C. 4th cent. A.D.) and Nevers lampworking glass (18th cent. A.D.). The fine examination of crystalline phases and of the vitreous matrix is undertaken using various and complementary techniques. Results are compared with a modern reference production, for which the technological process is well known. We demonstrate that Ca-antimonate opacifiers in Roman mosaic tesserae, as well as in Nevers lampworking glass, were obtained by in situ crystallization. Nevertheless, Roman and Nevers glass would have undergone different firing processes. We propose that the addition of previously synthesized crystals or the use of “anime” could be the process used to obtain Pb-antimonate opacified glass, for both productions studied. We demonstrate that CaO, PbO and Sb2O3 concentrations in the bulk compositions and in the matrices, and their evolution with the crystallinity ratio, offer robust criteria for the distinction of the opacification process used. Also, the different crystalline structures help to provide information on the experimental conditions.

  5. Differentiation of stem cells into insulin-producing cells under the influence of nanostructural polyoxometalates.

    Science.gov (United States)

    Bâlici, Ştefana; Şuşman, Sergiu; Rusu, Dan; Nicula, Gheorghe Zsolt; Soriţău, Olga; Rusu, Mariana; Biris, Alexandru S; Matei, Horea

    2016-03-01

    Two polyoxometalates (POMs) with W were synthesized by a two-step, self-assembling method. They were used for stimulation of mesenchymal stem cell differentiation into insulin-producing cells. The nanocompounds (tris(vanadyl)-substituted tungsto-antimonate(III) anions [POM1] and tris-butyltin-21-tungsto-9-antimonate(III) anions [POM2]) were characterized by analytical techniques, including ultraviolet-visible, Fourier transform infrared, nuclear magnetic resonance spectroscopy, and transmission electron microscopy. We found that these polyoxotungstates, with 2-4 nm diameters, did not present toxic effects at the tested concentrations. In vitro, POM1 stimulated differentiation of a greater number of dithizone-positive cells (also organized in clusters) than the second nanocompound (POM2). Based on our in vitro studies, we have concluded that both the POMs tested had significant biological activity acting as active stimuli for differentiation of stem cells into insulin-producing cells. PMID:26397720

  6. Treatment Approaches for Cutaneous Leishmaniasis

    Directory of Open Access Journals (Sweden)

    Sema Aytekin

    2009-06-01

    Full Text Available Cutaneous leishmaniasis (CL is a widespread tropical infection caused by numerous different species of Leishmania protozoa. In our country, CL is due frequently to L. major and L. tropica. Its clinical presentation is extremely diverse. Treatment of CL aims to prevent mucosal invasion, to accelerate the healing of skin lesions, and avoid disfiguring scar. Local and physical treatment modalities including topical paromomycin, cryotherapy, localized controlled heat, carbon dioxide laser therapy, or pentavalant antimonals can be effective against. Intralesional antimonals are still the drug of choice may patients. WHO recommends an injection of drug under edges of the lesions and the entire lesion until the surface has blanched. Parenteral antimonials are useful for large, persistent or recurrent lesions. Combinations with other drugs such as allopurinol, pentoxifylline must be used for antimony unresponsive lesions.

  7. Berberine derivatives as antileishmanial drugs.

    OpenAIRE

    Vennerstrom, J L; Lovelace, J K; Waits, V B; Hanson, W L; Klayman, D L

    1990-01-01

    Berberine, a quaternary alkaloid, and several of its derivatives were tested for efficacy against Leishmania donovani and Leishmania braziliensis panamensis in golden hamsters. Tetrahydroberberine was less toxic and more potent than berberine against L. donovani but was not as potent as meglumine antimonate (Glucantime), a standard drug for the treatment of leishmaniasis. Only berberine and 8-cyanodihydroberberine showed significant activity (greater than 50% suppression of lesion size) again...

  8. Süße Gifte

    OpenAIRE

    Betz, Richard

    2009-01-01

    Die vorliegende Arbeit beschreibt die Synthese und Charakterisierung ein- und mehrkerniger Diol-, Polyol- und Kohlenhydrat-Verbindungen von Elementen der vierten, fünften und sechsten Hauptgruppe des Periodensystems. Im Zentrum der Untersuchungen standen dabei Spiro-Derivate des fünfwertigen Phosphors, Arsens und Antimons, des vierwertigen Selens und Tellurs sowie spirocyclische Ester der Orthokohlensäure. Ferner wurden alpha-Hydroxycarbonsäuren, Aminosäuren, Aminole und Hydroxythiole au...

  9. Cortical alveoli of Paramecium: a vast submembranous calcium storage compartment

    OpenAIRE

    1991-01-01

    The plasma membrane of Paramecium is underlain by a continuous layer of membrane vesicles known as cortical alveoli, whose function was unknown but whose organization had suggested some resemblance with muscle sarcoplasmic reticulum. The occurrence of antimonate precipitates within the alveoli first indicated to us that they may indeed correspond to a vast calcium storage site. To analyze the possible involvement of this compartment in calcium sequestration more directly, we have developed a ...

  10. Test procedure for cation exchange chromatography

    International Nuclear Information System (INIS)

    The purpose of this test plan is to demonstrate the synthesis of inorganic antimonate ion exchangers and compare their performance against the standard organic cation exchangers. Of particular interest is the degradation rate of both inorganic and organic cation exchangers. This degradation rate will be tracked by determining the ion exchange capacity and thermal stability as a function of time, radiation dose, and chemical reaction

  11. Use of inorganic ion exchange materials for the treatment of liquid waste

    International Nuclear Information System (INIS)

    To examine the ion exchange behaviour of the double salts of polybasic acid with tetravalent metals type such as cerium(IV) and tin(IV) antimonates, different samples were prepared, heated at different temperatures and exposed to γ-irradiation. These samples were subject to X-ray, infra-red and thermal analysis. The exchange properties of the studied materials improved on increasing the Sb, Ce or Sn molar ratios and the drying temperature. The rate of the isotopic exchange was controlled by particle diffusion for the metal ions studied and was faster as the heating temperature was increased but slower for materials with a higher exchange capacity. The physical thermodynamic parameters have been evaluated which give some information regarding the mechanism of ion exchange on the surface of inorganic materials. The removal of radioactive isotopes of Na+, Cs+, Sr2+, Co2+ and Eu3+ was carried out by in-situ precipitation or by using preformed precipitate of tin(IV) and cerium(IV) antimonates. The products of in-situ precipitations act as ion exchange materials with high chemical and radioactive stabilities. The new materials have relatively high capacity compared with CeSb and SnSb. The irradiated cerium(IV) antimonate has been successfully used for the quantitative separation of cesium which suggests its use in the treatment of active liquid waste. (author). 24 refs, 7 figs, 17 tabs

  12. Alkali oxide-tantalum, niobium and antimony oxide ionic conductors

    Science.gov (United States)

    Roth, R. S.; Brower, W. S.; Parker, H. S.; Minor, D. B.; Waring, J. L.

    1975-01-01

    The phase equilibrium relations of four systems were investigated in detail. These consisted of sodium and potassium antimonates with antimony oxide and tantalum and niobium oxide with rubidium oxide as far as the ratio 4Rb2O:llB2O5 (B=Nb, Ta). The ternary system NaSbO3-Sb2O4-NaF was investigated extensively to determine the actual composition of the body centered cubic sodium antimonate. Various other binary and ternary oxide systems involving alkali oxides were examined in lesser detail. The phases synthesized were screened by ion exchange methods to determine mobility of the mobility of the alkali ion within the niobium, tantalum or antimony oxide (fluoride) structural framework. Five structure types warranted further investigation; these structure types are (1) hexagonal tungsten bronze (HTB), (2) pyrochlore, (3) the hybrid HTB-pyrochlore hexagonal ordered phases, (4) body centered cubic antimonates and (5) 2K2O:3Nb2O5. Although all of these phases exhibit good ion exchange properties only the pyrochlore was prepared with Na(+) ions as an equilibrium phase and as a low porosity ceramic. Sb(+3) in the channel interferes with ionic conductivity in this case, although relatively good ionic conductivity was found for the metastable Na(+) ion exchanged analogs of RbTa2O5F and KTaWO6 pyrochlore phases.

  13. Development and pharmacokinetic of antimony encapsulated in liposomes of phosphatidylserine using radioisotopes in experimental leishmaniasis

    International Nuclear Information System (INIS)

    Leishmaniasis are a complex of parasitic diseases caused by intra macrophage protozoa of the genus Leishmania, and is fatal if left untreated. Pentavalent antimonials, though toxic and their mechanism of action being unclear, remain the first-line drugs for treatment. Effective therapy could be achieved by delivering antileishmanial drugs to these sites of infection. Liposomes are phospholipid vesicles that promote improvement in the efficacy and action of drugs in target cell. Liposomes are taken up by the cells of mononuclear phagocytic system (MPS). The purpose of this study was to develop a preparation of meglumine antimonate encapsulated in liposomes of phosphatidylserine and to study its pharmacokinetic in healthy mice to establish its metabolism and distribution. Quantitative analysis of antimony from liposomes demonstrated that Neutron Activation Analysis was the most sensitive technique with almost 100 % of accuracy. All liposome formulations presented a mean diameter size of 150 nm. The determination of IC50 in infected macrophage showed that liposome formulations were between 10 - 63 fold more effective than the free drug, indicating higher selectivity index. By fluorescence microscopy, an increased uptake of fluorescent-liposomes was seen in infected macrophages during short times of incubation compared with non-infected macrophages. Biodistribution studies showed that meglumine antimonate irradiated encapsulated in liposomes of phosphatidylserine promoted a targeting of antimony for MPS tissues and maintained high doses in organs for a prolonged period. In conclusion, these data suggest that meglumine antimonate encapsulated in liposomes showed higher effectiveness than the non-liposomal drug against Leishmania infection. The development of liposome formulations should be a new alternative for the chemotherapy of infection diseases, especially Leishmaniasis, as they are used to sustain and target pharmaceuticals to the local of infection. (author)

  14. Development and pharmacokinetic of antimony encapsulated in liposomes of phosphatidylserine using radioisotopes in experimental leishmaniasis; Desenvolvimento e farmacocinetica de antimonio encapsulado em lipossomas de fosfatidilserina utilizando radioisotopos em leishmaniose experimental

    Energy Technology Data Exchange (ETDEWEB)

    Borborema, Samanta Etel Treiger

    2010-07-01

    Leishmaniasis are a complex of parasitic diseases caused by intra macrophage protozoa of the genus Leishmania, and is fatal if left untreated. Pentavalent antimonials, though toxic and their mechanism of action being unclear, remain the first-line drugs for treatment. Effective therapy could be achieved by delivering antileishmanial drugs to these sites of infection. Liposomes are phospholipid vesicles that promote improvement in the efficacy and action of drugs in target cell. Liposomes are taken up by the cells of mononuclear phagocytic system (MPS). The purpose of this study was to develop a preparation of meglumine antimonate encapsulated in liposomes of phosphatidylserine and to study its pharmacokinetic in healthy mice to establish its metabolism and distribution. Quantitative analysis of antimony from liposomes demonstrated that Neutron Activation Analysis was the most sensitive technique with almost 100 % of accuracy. All liposome formulations presented a mean diameter size of 150 nm. The determination of IC{sub 50} in infected macrophage showed that liposome formulations were between 10 - 63 fold more effective than the free drug, indicating higher selectivity index. By fluorescence microscopy, an increased uptake of fluorescent-liposomes was seen in infected macrophages during short times of incubation compared with non-infected macrophages. Biodistribution studies showed that meglumine antimonate irradiated encapsulated in liposomes of phosphatidylserine promoted a targeting of antimony for MPS tissues and maintained high doses in organs for a prolonged period. In conclusion, these data suggest that meglumine antimonate encapsulated in liposomes showed higher effectiveness than the non-liposomal drug against Leishmania infection. The development of liposome formulations should be a new alternative for the chemotherapy of infection diseases, especially Leishmaniasis, as they are used to sustain and target pharmaceuticals to the local of infection. (author)

  15. 无机锑系阻燃剂%Inorganic Antimony Series Fire Retardants

    Institute of Scientific and Technical Information of China (English)

    张亨

    2012-01-01

    无机锑系阻燃剂主要包括三氧化二锑、五氧化二锑溶胶和锑酸钠等。介绍了它们的性质、生产工艺、产品标准、阻燃用途和研发方向等。%Inorganic antimony series fire retardants include antimony trioxide, antimony pentoxide sol and sodium antimonate, etc. The properties, production process, production standard and uses of several inorganic antimony series fire retardants are introduced.

  16. Temporal and spatial changes in Ca2+ distribution during the programmed cell death of tracheary elements

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The changes in Ca2+ distribution in the tracheary elements (TEs) of the pepper leaves were studied using the cytochemical method of potassium antimonate. At the early stage of TEs formation, the vacuole and the nucleus held large volume, and antimonate Ca2+ deposits were observed mainly in the intercellular space and the cell wall. As the thickening of secondary wall occurred, the vacuole, nucleus and other organelles began to rupture, concomitant with the increase of calcium deposits in the cytosol, showing the influx of Ca2+ into the cell. With the further rupture of cytoplasm and other organelles, the number of calcium deposits at the non-thickening cell wall increased, but declined at the thickening bands of the secondary wall. When the cytoplasmic contents disappeared completely, the level of Ca2+ decreased at the non-thickening wall, but by contrast,increased at the thickening bands of the secondary wall.These observations indicated that the dynamic changes in Ca2+ distribution spatially and temporarily might have a close correlation with its distinct roles played during the formation of the secondary walls.

  17. Cation-selective extraction column study for the conception of nuclear medical radionuclide generators; Untersuchung kationenselektiver Extraktionssaeulen zur Konzeption nuklearmedizinischer Radionuklidgeneratoren

    Energy Technology Data Exchange (ETDEWEB)

    Streng, Roman

    2012-07-09

    The topic of the present work is the conception of a Yttrium-90 radionuclide generator for nuclear medicine applications. Due to its physical properties Yttrium-90 is considered as one of the most useful nuclides for radiotherapeutic cancer treatment. The parent nuclide Strontium-90 is gained during reprocessing of fission products. Thus, the sustained availability of large quantities of Yttrium-90 is limited to a number of research facilities. A radionuclide generator provides an independent Yttrium-90 source and enhances the capacities for radiopharmaceutical research and biomedical applications. The present work focussed on the identification of appropriate column materials for the separation of Strontium and Yttrium. The results for two materials are reported: AnaLig {sup registered} Sr-01 and crystalline antimonic acid. Based on the mode of operation of the Technetium-99m generator the aim was to enable the construction of a compact, enclosed apparatus. The projected device comprises a reservoir for the eluant, the ion-exchange column, pipings and radiation shielding. Elution of Yttrium-90 could then be easily performed by connecting evacuated vials to the outlet tube. The prospected concept involves physical and chemical confinements that exclude most of the known processes for Strontium-Yttrium separation. For example no ligands, no oxidizing reactants (e.g. nitric acid) and no organic solvents are to be used, but small volumes of isotonic or buffer solutions and dilute acids respectively. AnaLig {sup registered} Sr-01 is a commercially available resin used in extraction chromatography. Its high selectivity for Strontium cations results from the strictly defined cavity of the imbedded cryptand. Determination of weight distribution coefficients, elution studies and pre-generator experiments were carried out. Quantitative separation of Yttrium from Strontium and Zirconium is possible using small volumes of 0,05 M hydrochloric acid as eluant. Furthermore, high

  18. Cutaneous Leishmaniasis with Unusual Clinical and Histological Presentation: Report of Four Cases

    Directory of Open Access Journals (Sweden)

    Hamideh Moravvej

    2013-04-01

    Full Text Available Old world cutaneous leishmaniasis (OWCL usually causes a single, self-healing and uncomplicated lesion mainly on the exposed area of body. This report presents four cases of OWCL from Iran that misdiagnosed with sarcoidosis, lymphoma, and acne agminata. Two out of four patients showed a history of purplish red plaques for at least 5 years who misdiagnosed as sarcoidosis because of histological and clinical characteristics. The other one presented with flesh-colored nodules disseminated all over his skin that was misdiagnosed as lymphoma for ten years. The last patient was misdiagnosed as acne agminata due to tuberculoid reactions in examination of the lesion biopsy. All the patients responded to the treatment with meglumine antimonate.

  19. Microbial antimony biogeochemistry: Enzymes, regulation, and related metabolic pathways

    Science.gov (United States)

    Li, Jingxin; Qian Wang,; Oremland, Ronald S.; Kulp, Thomas R.; Rensing, Christopher; Wang, Gejiao

    2016-01-01

    Antimony (Sb) is a toxic metalloid that occurs widely at trace concentrations in soil, aquatic systems, and the atmosphere. Nowadays, with the development of its new industrial applications and the corresponding expansion of antimony mining activities, the phenomenon of antimony pollution has become an increasingly serious concern. In recent years, research interest in Sb has been growing and reflects a fundamental scientific concern regarding Sb in the environment. In this review, we summarize the recent research on bacterial antimony transformations, especially those regarding antimony uptake, efflux, antimonite oxidation, and antimonate reduction. We conclude that our current understanding of antimony biochemistry and biogeochemistry is roughly equivalent to where that of arsenic was some 20 years ago. This portends the possibility of future discoveries with regard to the ability of microorganisms to conserve energy for their growth from antimony redox reactions and the isolation of new species of “antimonotrophs.”

  20. Cation-selective extraction column study for the conception of nuclear medical radionuclide generators; Untersuchung kationenselektiver Extraktionssaeulen zur Konzeption nuklearmedizinischer Radionuklidgeneratoren

    Energy Technology Data Exchange (ETDEWEB)

    Streng, Roman

    2012-07-09

    The topic of the present work is the conception of a Yttrium-90 radionuclide generator for nuclear medicine applications. Due to its physical properties Yttrium-90 is considered as one of the most useful nuclides for radiotherapeutic cancer treatment. The parent nuclide Strontium-90 is gained during reprocessing of fission products. Thus, the sustained availability of large quantities of Yttrium-90 is limited to a number of research facilities. A radionuclide generator provides an independent Yttrium-90 source and enhances the capacities for radiopharmaceutical research and biomedical applications. The present work focussed on the identification of appropriate column materials for the separation of Strontium and Yttrium. The results for two materials are reported: AnaLig {sup registered} Sr-01 and crystalline antimonic acid. Based on the mode of operation of the Technetium-99m generator the aim was to enable the construction of a compact, enclosed apparatus. The projected device comprises a reservoir for the eluant, the ion-exchange column, pipings and radiation shielding. Elution of Yttrium-90 could then be easily performed by connecting evacuated vials to the outlet tube. The prospected concept involves physical and chemical confinements that exclude most of the known processes for Strontium-Yttrium separation. For example no ligands, no oxidizing reactants (e.g. nitric acid) and no organic solvents are to be used, but small volumes of isotonic or buffer solutions and dilute acids respectively. AnaLig {sup registered} Sr-01 is a commercially available resin used in extraction chromatography. Its high selectivity for Strontium cations results from the strictly defined cavity of the imbedded cryptand. Determination of weight distribution coefficients, elution studies and pre-generator experiments were carried out. Quantitative separation of Yttrium from Strontium and Zirconium is possible using small volumes of 0,05 M hydrochloric acid as eluant. Furthermore, high

  1. Determination of arsenic in antimony ingot and antimony trioxide by hydride generation-atomic fluorescence spectrometry%氢化物发生-原子荧光光谱法测定锑锭及三氧化二锑中的砷

    Institute of Scientific and Technical Information of China (English)

    钱光敏; 赵国杏

    2012-01-01

    The antimony slab and antimonous oxide samples were dissolved by sulfuric acid and hydrochloric acid, respectively. The Sb3+ in solution was precipitated with sodium hydroxide to separate trace arsenic from matrix antimony. The thiourea-ascorbic acid was added to reduce As5+ to As3+. Then, the arsenic in antimony slab and antimonous oxide was determined by atomic fluorescence spec-trometry. The hydride generation conditions were investigated: the concentration of reducing agent potassium borohydride was 25 g/L, the determination medium was 20% (V/V) hydrochloric acid, and the dosage of thiourea - ascorbic acid solution was 5 mL. The interference test of coexisting elements showed that, the interference of residual antimony in solution after precipitation could be fully eliminated by adding 1 mL of tartaric acid solution. Other impurity elements in sample did not interfere with the determination of arsenic after adding thiourea-ascorbic acid solution. The detection limit of method was 0. 156 ng/mL. The antimony slab and antimonous oxide samples were analyzed by the proposed method, and the relative standard deviation (RSD) was 0. 95%-1.2%. The determination results were consistent with those obtained by national standard methods.%采用硫酸溶解锑锭样品,盐酸溶解三氧化二锑样品,用氢氧化钠溶液使Sb3+沉淀从而使基体锑与微量砷分离,通过加入硫脲-抗坏血酸将As5+还原成As3+,然后在原子荧光仪上测定锑锭及三氧化二锑中的砷.对氢化物发生条件进行考察,确定还原剂硼氢化钾的浓度为25 g/L、测定介质为20%(V/V)盐酸、硫脲-抗坏血酸溶液用量为5 mL.共存元素干扰试验表明,沉淀后溶液中残留少量锑的干扰在加入1 mL酒石酸溶液后可以完全消除,而样品中其他杂质元素在加入硫脲-抗坏血酸溶液后不干扰砷的测定.方法的检出限为0.156 ng/mL.对锑锭及三氧化二锑样品进行分析,相对标准偏差为0.95%~1.2%,测定

  2. Solubility behaviour of antimony(III) and antimony(V) solids in basic aqueous solutions at 300{sup o}C

    Energy Technology Data Exchange (ETDEWEB)

    Lemire, R.J.; Tosello, N.B.; Halliday, J.D

    1999-12-01

    The major contributions of the isotopes {sup 122}Sb and {sup 124}Sb to activity transport in a CANDU reactor primary heat transport system (HTS), have been associated with oxygen ingress during reactor shutdown. As part of a program to minimize the release and redeposition of these isotopes, the solubilities of antimony(III) and (V) oxides and salts have been measured in basic solutions at temperatures from 25 to 300{sup o}C. The results provide information on the charge and the stability as a function of temperature of antimony solution species and, hence, a guide to the trends in the temperature dependence of the solubilities of antimony solids. In solutions in which oxidation of antimony(III) to antimony(V) is minimized, the solubility of Sb{sub 2}O{sub 3} increases by about two orders of magnitude between 25 and 200{sup o}C, and then levels out or decreases slightly. At 250{sup o}C, in oxidizing solutions, Sb{sub 2}O{sub 5}{center_dot}xH{sub 2}O and simple sodium antimonate(V) were found to be unstable in sodium hydroxide solutions with respect to the solid, Na{sub 2{alpha}}[H(H{sub 2}O)]{sub 2-2{alpha}}Sb{sub 2}O{sub 6}, which has a pyrochlore structure. The solubility of this partially protonated sodium antimonate increases from 25 to 200{sup o}C and decreases at temperatures above 250{sup o}C. These solubility changes for the antimony (V) solids reflect changes in the stability of the anionic antimony solution species (SbO{sub 3}{sup -} or Sb(OH){sub 6}{sup -}), even though the compositions of antimony-containing solids in basic oxidizing solutions are strongly dependent on the cations and their aqueous phase concentrations. All solids used in the present experiments would be expected to generate total solution antimony concentrations {>=} 0.00005 mol{center_dot}dm{sup -3} in any neutral or basic aqueous solutions (assuming no added sodium salts). Therefore, under HTS conditions, precipitation of any antimony oxides or mixed oxides is unlikely. It cannot be

  3. Influence of Post-Modernism on Modern Psychology%后现代主义对现代心理学的影响

    Institute of Scientific and Technical Information of China (English)

    刘皓月; 贾林祥

    2012-01-01

    后现代主义的产生,给面临严重危机和困难的现代心理学带来了机遇和希望。后现代主义对心理学的影响主要有:反一元主义,提倡多元化;反个体主义,提倡人际互动;反基础主义,提倡社会建构;反科学主义,提倡与人文主义融合。后现代主义百家争鸣的状态对现代心理学的影响是有利而无害的。%The generation of post-modernism brings opportunities and hope to modern psychology which is facing a serious crisis and difficulties.The effects of the post-modernism to the psychology are mainly: anti-monism and encouraging diversification;anti-individualism and promoting social interaction;anti-fundamentalism and promoting social construction;anti-scientism and advocating integration with humanism.The influence of the contending state of the postmodernism on the modern psychology is beneficial and harmless.

  4. Clinical features, epidemiology, and efficacy and safety of intralesional antimony treatment of cutaneous leishmaniasis: recent experience in Turkey.

    Science.gov (United States)

    Uzun, Soner; Durdu, Murat; Culha, Gulnaz; Allahverdiyev, Adil M; Memisoglu, Hamdi R

    2004-08-01

    A total of 1,030 patients, 40.2% men and 59.8% women, identified during the period of October 1998 to November 2002 as having cutaneous leishmaniasis (CL), were studied; 1,431 lesions were identified in the 1,030 patients. One lesion was present in 80.7% of the patients. The size of the lesions (longest axis) was 13.6 mm (standard, 12.1 mm; range 3-150 mm). Most of the lesions were of the papular type (51.2%), although several atypical clinical presentations of CL were observed. The duration of the disease ranged between 1 and 72 mo (mean duration, 10.8 mo). The clinical suspicion of CL was confirmed by the observation of amastigotes on lesion tissue samples stained by Giemsa. The test was positive in 851 of 1,030 patients (82.6%). Intralesional meglumine antimonate solution (85 mg Sb/ml, 0.2-1 ml, depending on the size of the lesion) weekly until complete cure or up to 20 wk was used for first-line therapy of 890 patients (86.4%). We found that this regimen of intralesional Sb has an efficacy of 97.2% with a low relapse rate of 3.9% and no serious adverse side effects. PMID:15357081

  5. Calcium pretreatment increases thermotolerance of Laminaria japonica sporophytes

    Institute of Scientific and Technical Information of China (English)

    You Wang; Qingyun Yu; Xuexi Tang; Lili Wang

    2009-01-01

    Calcium is a secondary messenger in plant signaling,and its concentration changes spatially and temporally during the course of heat stress.In the present study,potassium antimonate was used to visualize calcium localization in blades of a marine macroalga,the juvenile Laminariajaponica sporophytes under heat stress (25 ℃).Result showed that loosely bound calcium was mainly distributed on the cell wall under normal conditions (10 ℃),and flowed into the cytoplasm when exposed to heat.The simutaneous assay on the antioxidant system changes was performed.Oxidative damage,as measured by generation of reactive oxygen species (ROS) malondialdehyde (MDA) content,increased significantly during heat stress,and calcium pretreatment alleviated oxidative damage.The assay on the activities of six antioxidant enzymes demonstrated that their enzymatic activities were inhibited when exposed to heat stress,but Ca2+ pretreatment effectively attenuated the inhibition.Results in the present study inferred that calcium homeostasis plays an essential role in L.japonica sporophyte when exposed to heat,and calcium pretreatment could improve its thermo-tolerance.

  6. Removal of cobalt from zinc sulphate solution using rude antimony trioxide as additive

    Institute of Scientific and Technical Information of China (English)

    戴军; 王德全; 姜澜; 金曼

    2002-01-01

    The process of cobalt removal from zinc sulphate solution using rude antimony trioxide as an additive was investigated. The rude antimony trioxide was produced in treatment of copper and lead anode mud and its main components are antimony trioxide, antimony arsenate and lead antimonate. Using the rude antimony trioxide as the additive of cobalt removal can not only decrease operation cost of purification but also find out a new way for utilization of the rude antimony trioxide. The effects of temperature, dosage of zinc dust, the rude antimony trioxide, copper ion and solution pH on removal of cobalt were studied. And experimental data using the rude Sb2O3 as additive were compared with those using Sb2O3. The results indicate that using rude Sb2O3 as additive, cobalt concentration in solution could be decreased from 24mg/L to below 1mg/L under about the same conditions as using Sb2O3.

  7. Composition and microstructure of maiolica from the museum of ceramics in Ascoli Piceno (Italy): evidences by electron microscopy and microanalysis

    Science.gov (United States)

    Gulmini, M.; Scognamiglio, F.; Roselli, G.; Vaggelli, G.

    2015-09-01

    The present work focuses on majolica objects from the collection of the museum of ceramic in Ascoli Piceno (Italy). The scientific investigation was performed on fragments detached from seven maiolicas attributed to the Castelli production (Abruzzi region) and one majolica from the Ascoli Piceno production (Marche region). The Castelli artifacts (late sixteenth-early eighteenth century) belong to the decorated style known as " compendiario." The piece from Ascoli Piceno recalls the decoration style of the other considered objects and is attributable to the "Paci" manufacture (first half of the nineteenth century). The selected objects were investigated by fiber optics reflectance spectroscopy, micro-X-ray fluorescence spectroscopy and scanning electron microscopy coupled with electron-dispersive X-ray spectrometry. The ceramic bodies of all objects are calcareous, whereas the glazes are lead-alkali type opacified by tin dioxide. Blue and purplish-red decorations were obtained by cobalt and manganese compounds dissolved in the glaze, respectively. Yellow and orange decorations were obtained by particles of lead antimonate and hematite. Finally, black decorations were obtained using compounds rich in manganese and iron. The study contributes to knowledge on the production of Castelli ceramics and presents first archaeometric data on the maiolica production from Ascoli Piceno. The scientific examination highlights continuity with the Renaissance production, and the joint contribution of the three analytical techniques suggests distinctive features among different productions, thus integrating and refining the information obtained by the art-historical study.

  8. In vivo antileishmanial activity and chemical profile of polar extract from Selaginella sellowii

    Directory of Open Access Journals (Sweden)

    Dayane Priscilla de Souza Queiroz

    2016-01-01

    Full Text Available The polar hydroethanolic extract from Selaginella sellowii(SSPHE has been previously proven active on intracellular amastigotes (in vitro test and now was tested on hamsters infected with Leishmania (Leishmania amazonensis (in vivo test. SSPHE suppressed a 100% of the parasite load in the infection site and draining lymph nodes at an intralesional dose of 50 mg/kg/day × 5, which was similar to the results observed in hamsters treated with N-methylglucamine antimonate (Sb (28 mg/Kg/day × 5. When orally administered, SSPHE (50 mg/kg/day × 20 suppressed 99.2% of the parasite load in infected footpads, while Sb suppressed 98.5%. SSPHE also enhanced the release of nitric oxide through the intralesional route in comparison to Sb. The chemical fingerprint of SSPHE by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry showed the presence of biflavonoids and high molecular weight phenylpropanoid glycosides. These compounds may have a synergistic action in vivo. Histopathological study revealed that the intralesional treatment with SSPHE induced an intense inflammatory infiltrate, composed mainly of mononuclear cells. The present findings reinforce the potential of this natural product as a source of future drug candidates for American cutaneous leishmaniasis.

  9. A fruitful demonstration in sensors based on upconversion luminescence of Yb3+/Er3+codoped Sb2O3-WO3-Li2O (SWL) glass-ceramic

    Science.gov (United States)

    Prasad Sukul, Prasenjit; Kumar, Kaushal

    2016-07-01

    In this article, erbium and ytterbium doped lithium tungsten antimonate (Yb3+/Er3+:Sb2O3-WO3-Li2O) glass-ceramics (GC) is synthesized and its novel applications in temperature sensing and detection of latent fingerprints is studied. It is also estimated that this material could be useful as a solar cell concentrator. The upconversion emission studies on Yb3+/Er3+:SWL glass-ceramics have shown intense green emission at 525 nm (2H11/2 → 4I15/2) & 545 nm (4s3/2 → 4I15/2). The variation of UC intensities with external temperature have shown a well-fashioned pattern, which suggests that the 2H11/2 and 4S3/2 levels of Er3+ ion are thermally coupled and can act as a temperature sensor in the 300-500 K temperature range. Dry powder of Yb3+/Er3+:SWL glass-ceramic is used to develop latent fingerprint with high contrast in green color on glass slide.

  10. PXRF, μ-XRF, vacuum μ-XRF, and EPMA analysis of Email Champlevé objects present in Belgian museums.

    Science.gov (United States)

    Van der Linden, Veerle; Meesdom, Eva; Devos, Annemie; Van Dooren, Rita; Nieuwdorp, Hans; Janssen, Elsje; Balace, Sophie; Vekemans, Bart; Vincze, Laszlo; Janssens, Koen

    2011-10-01

    The enamel of 20 Email Champlevé objects dating between the 12th and 19th centuries was investigated by means of microscopic and portable X-ray fluorescence analysis (μ-XRF and PXRF). Seven of these objects were microsampled and the fragments were analyzed with electron probe microanalysis (EPMA) and vacuum μ-XRF to obtain quantitative data about the composition of the glass used to produce these enameled objects. As a result of the evolution of the raw materials employed to produce the base glass, three different compositional groups could be discriminated. The first group consisted of soda-lime-silica glass with a sodium source of mineral origin (with low K content) that was opacified by addition of calcium antimonate crystals. This type of glass was only used in objects made in the 12th century. Email Champlevé objects from the beginning of the 13th century onward were enameled with soda-lime-silica glass with a sodium source of vegetal origin. This type of glass, which has a higher potassium content, was opacified with SnO2 crystals. The glass used for 19th century Email Champlevé artifacts was produced with synthetic and purified components resulting in a different chemical composition compared to the other groups. Although the four analytical techniques employed in this study have their own specific characteristics, they were all found to be suitable for classifying the objects into the different chronological categories. PMID:21939587

  11. Protons conductive membranes from sulfonated styrenic copolymers; Membranas conductoras de protons a partir de copolimeros estirenicos sulfonados

    Energy Technology Data Exchange (ETDEWEB)

    Brum, F.J.B.; Silva, M.A.G.; Amico, S.C.; Malfatti, C.F.; Forte, M.M.C. [Universidade Federal do Rio Grande do Sul (EE/UFRGS), Porto Alegre, RS (Brazil). Escola de Engenharia], e-mail: mmcforte@ufrgs.br; Vargas, J.V.C. [Universidade Federal do Parana (DEM/UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Mecanica

    2008-07-01

    Fuel cells working with polymeric electrolyte known as Proton Exchange Membrane Fuel Cell (PEMFC) have become a promising source for energy generation since they can produce high density electric current in an effective way. In this work, a polymeric precursor based on sulfonated styrenic copolymer (RHS) was used with the aim of producing ion-exchange membranes thermally stable at 80 deg C and over. Films of RHS and poly(vinylalcohol) (PVA) mixtures with different polyelectrolyte content were prepared, using glutaraldehyde as a crosslinking agent and antimonic acid. The films or membranes were analyzed by infrared and electrochemical impedance spectroscopy, differential scanning calorimetry, thermogravimetry and water absorption content. The impedance studies showed that the ionic conductivity of the RHS/PVA membranes was highly dependent on the electrolyte polymer in a way that the higher the content, the higher the membrane ionic conductivity. The RHS66{sub G}1 showed ionic conductivity similar to the Nafion membrane analyzed at the same conditions. (author)

  12. A new method for antimony speciation in plant biomass and nutrient media using anion exchange cartridge.

    Science.gov (United States)

    Tisarum, Rujira; Ren, Jing-Hua; Dong, Xiaoling; Chen, Hao; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    A selective separation method based on anion exchange cartridge was developed to determine antimony (Sb) speciation in biological matrices by graphite furnace atomic absorption spectrophotometry (GFAAS). The selectivity of the cartridge towards antimonite [Sb(III)] and antimonate [Sb(V)] reversed in the presence of deionized (DI) water and 2mM citric acid. While Sb(V) was retained by the cartridge in DI water, Sb(III) was retained in citric acid media. At pH 6, Sb(III) and Sb(V) formed Sb(III)- and Sb(V)-citrate complexes, but the cartridge had higher affinity towards the Sb(III)-citrate complex. Separation of Sb(III) was tested at various concentrations in fresh and spent growth media and plant tissues. Our results showed that cartridge-based Sb speciation was successful in plant tissues, which was confirmed by HPLC-ICP-MS. The cartridge retained Sb(III) and showed 92-104% Sb(V) recovery from arsenic hyperaccumulator Pteris vittata roots treated with Sb(III) and Sb(V). The cartridge procedure is an effective alternative for Sb speciation, offering low cost, reproducible results, and simple Sb analysis using GFAAS.

  13. Chronic exposure to arsenic in drinking water can lead to resistance to antimonial drugs in a mouse model of visceral leishmaniasis

    Science.gov (United States)

    Perry, Meghan R.; Wyllie, Susan; Raab, Andrea; Feldmann, Joerg; Fairlamb, Alan H.

    2013-01-01

    The Indian subcontinent is the only region where arsenic contamination of drinking water coexists with widespread resistance to antimonial drugs that are used to treat the parasitic disease visceral leishmaniasis. We have previously proposed that selection for parasite resistance within visceral leishmaniasis patients who have been exposed to trivalent arsenic results in cross-resistance to the related metalloid antimony, present in the pentavalent state as a complex in drugs such as sodium stibogluconate (Pentostam) and meglumine antimonate (Glucantime). To test this hypothesis, Leishmania donovani was serially passaged in mice exposed to arsenic in drinking water at environmentally relevant levels (10 or 100 ppm). Arsenic accumulation in organs and other tissues was proportional to the level of exposure and similar to that previously reported in human liver biopsies. After five monthly passages in mice exposed to arsenic, isolated parasites were found to be completely refractory to 500 μg⋅mL−1 Pentostam compared with the control passage group (38.5 μg⋅mL−1) cultured in vitro in mouse peritoneal macrophages. Reassessment of resistant parasites following further passage for 4 mo in mice without arsenic exposure showed that resistance was stable. Treatment of infected mice with Pentostam confirmed that resistance observed in vitro also occurred in vivo. We conclude that arsenic contamination may have played a significant role in the development of Leishmania antimonial resistance in Bihar because inadequate treatment with antimonial drugs is not exclusive to India, whereas widespread antimonial resistance is. PMID:24167266

  14. Synthesis, characterization, sintering and dielectric properties of nanostructured perovskite-type oxide, Ba2GdSbO6

    Indian Academy of Sciences (India)

    C Vijayakumar; H Padma Kumar; Sam Solomon; J K Thomas; P R S Warriar; J Koshy

    2008-10-01

    Nanoparticles of barium gadolinium antimonate (Ba2GdSbO6), a complex perovskite-type oxide, has been synthesized using an auto ignition combustion process for the first time. The nanoparticles thus obtained have been characterized by powder X-ray diffraction, thermogravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy and transmission electron microscopy. The XRD studies have shown that the as-prepared powder is phase pure Ba2GdSbO6 and has a complex cubic perovskite (A2BB′O6) crystalline structure with lattice constant, = 8.449 Å. The TEM image reveals that the particle size of the as-prepared nano powder was in the range 30–60 nm. The nanocrystals of Ba2GdSbO6 synthesized by the combustion technique could be sintered to 96% of the theoretical density by heating at a temperature of 1560°C for a short duration of 3 h. The surface morphology of the sintered pellet has been studied by scanning electron microscope (SEM). The dielectric constant ($\\varepsilon_{r}$) was 20 and the loss factor (tan) was 0.03 at 3 MHz. By the present combustion technique a phase pure nanopowder of Ba2GdSbO6 could be obtained by a single step process without the need of any calcination step.

  15. Effects of Exterior Abscisic Acid on Calcium Distribution of Mesophyll Cells and Calcium Concentration of Guard Cells in Maize Seedlings

    Institute of Scientific and Technical Information of China (English)

    GUO Xiu-lin; MA Yuan-yuan; LIU Zi-hui; LIU Bin-hui

    2008-01-01

    In this study, the direct effects of exterior abscisic acid (ABA) on both calcium distribution of mesophyll cells and cytosolic calcium concentration of guard cells were examined. The distribution of Ca2+ localization were observed with calcium antimonate precipitate-electromicroscopic-cyto-chemical methods after treated with ABA and pretreated with ethylene glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), verapamil (Vp), and trifluoperazine (TFP). The laser scanning confocal microscopy was used to measure the cytosolic calcium concentrations of guard cells under different treatments. The results showed that the cytosolic Ca2+ concentration of mesophyll cells was induced to increase by ABA, but to decrease in both outside cell and the vacuoles within 10 min after treatments. The cytosolic calcium concentration of guard cells was increased gradually with the lag in treatment time. However, both EGTA and TFP could inverse those effects, indicating that the increase of cytosolic calcium induced by exterior ABA was mainly caused by calcium influx. The results also showed that calmodulin could influence both the calcium distribution of mesophyll cells and calcium concentration of guard cells. It shows that calmodulin participates in the process of ABA signal transduction, but the mechanism is not known as yet. The changes both calcium distribution of mesophyll cells and calcium concentration of guard cells further proved that the variations of cytosolic Ca2+ concentration induced by ABA were involved in the stomatal movements of maize seedlings.

  16. A synthetic, spectroscopic and magnetic susceptibility study of selected main group and transition metal fluoro compounds

    Energy Technology Data Exchange (ETDEWEB)

    Cader, M.S.R.

    1992-01-01

    This study was initiated in order to synthesize and to investigate the magnetic properties of selected main group and transition metal cationic complexes, all stabilized by weakly basic fluoro anions derived either from the Broensted superacids HSO[sub 3]F and HSO[sub 3]CF[sub 3], or the Lewis acids SbF[sub 5] and AsF[sub 5]. The solvolysis of metal(II) fluorosulfates in excess SbF[sub 5] is found to be a useful synthetic route to the corresponding divalent hexafluoro antimonates. The Sn(SbF[sub 6])[sub 2] product from the above synthesis, and its precursor Sn(SO[sub 3]F)[sub 2], react with excess 1,3,5-trimethylbenzene(mes) to give the [pi]-arene adducts Sn(SbF[sub 6])[sub 2][center dot]2mes and Sn(SO[sub 3]F)[sub 2][center dot]mes in high yield. The adducts are characterized by elemental analysis and infrared spectra. The adduct formation is followed by [sup 119]Sn Moessbauer spectroscopy. The divalent fluorosulfates Ni(SO[sub 3]F)[sub 2], Pd(SO[sub 3]F)[sub 2], Pd(SO[sub 3]F)[sub 2] and Ag(SO[sub 3]F)[sub 2], precursors to the M(SbF[sub 6])[sub 2] compounds, and the mixed valency Pd(II) [Pd(IV)(SO[sub 3]F)[sub 6

  17. Cytochemical localization of calcium in cap cells of primary roots of Zea mays L

    Science.gov (United States)

    Moore, R.

    1986-01-01

    The distribution of calcium (Ca) in caps of vertically- and horizontally-oriented roots of Zea mays was monitored to determine its possible role in root graviresponsiveness. A modification of the antimonate precipitation procedure was used to localize Ca in situ. In vertically-oriented roots, the presumed graviperceptive (i.e., columella) cells were characterized by minimal and symmetric staining of the plasmalemma and mitochondria. No precipitate was present in plasmodesmata or cell walls. Within 5 min after horizontal reorientation, staining was associated with the portion of the cell wall adjacent to the distal end of the cell. This asymmetric staining persisted throughout the onset of gravicurvature. No staining of lateral cell walls of columella cells was observed at any stage of gravicurvature, suggesting that a lateral flow of Ca through the columella tissue of horizontally-oriented roots does not occur. The outermost peripheral cells of roots oriented horizontally and vertically secrete Ca through plasmodesmata-like structures in their cell walls. These results are discussed relative to proposed roles of root-cap Ca in root gravicurvature.

  18. Chronic exposure to arsenic in drinking water can lead to resistance to antimonial drugs in a mouse model of visceral leishmaniasis.

    Science.gov (United States)

    Perry, Meghan R; Wyllie, Susan; Raab, Andrea; Feldmann, Joerg; Fairlamb, Alan H

    2013-12-01

    The Indian subcontinent is the only region where arsenic contamination of drinking water coexists with widespread resistance to antimonial drugs that are used to treat the parasitic disease visceral leishmaniasis. We have previously proposed that selection for parasite resistance within visceral leishmaniasis patients who have been exposed to trivalent arsenic results in cross-resistance to the related metalloid antimony, present in the pentavalent state as a complex in drugs such as sodium stibogluconate (Pentostam) and meglumine antimonate (Glucantime). To test this hypothesis, Leishmania donovani was serially passaged in mice exposed to arsenic in drinking water at environmentally relevant levels (10 or 100 ppm). Arsenic accumulation in organs and other tissues was proportional to the level of exposure and similar to that previously reported in human liver biopsies. After five monthly passages in mice exposed to arsenic, isolated parasites were found to be completely refractory to 500 μg · mL(-1) Pentostam compared with the control passage group (38.5 μg · mL(-1)) cultured in vitro in mouse peritoneal macrophages. Reassessment of resistant parasites following further passage for 4 mo in mice without arsenic exposure showed that resistance was stable. Treatment of infected mice with Pentostam confirmed that resistance observed in vitro also occurred in vivo. We conclude that arsenic contamination may have played a significant role in the development of Leishmania antimonial resistance in Bihar because inadequate treatment with antimonial drugs is not exclusive to India, whereas widespread antimonial resistance is.

  19. Anion-Controlled Positional Switching of a Phenyl Group about the Dinuclear Core of a AuSb Complex.

    Science.gov (United States)

    Sen, Srobona; Ke, Iou-Sheng; Gabbaï, François P

    2016-09-19

    As part of our continuing interest in redox-active, anion-responsive main-group transition-metal platforms, we have investigated the effect of chloride by fluoride anion substitution on the core structure of a dinuclear AuSb platform. Starting from [(o-(iPr2P)C6H4)2Cl2SbPh]AuCl (2) in which the antimony-bound phenyl group is positioned trans to the gold atom, we found that the introduction of fluoride anions, as in [(o-(iPr2P)C6H4)2F2SbPh]AuCl (3) and [(o-(iPr2P)C6H4)2ClFSbPh]AuCl (4), produces structures in which the phenyl group switches to a perpendicular direction with respect to the gold atom. Replacement of the gold-bound chloride anion in 3 by a fluoride anion can be achieved by successive treatment with TlPF6 and [nBu4N][Ph3SiF2]. These reactions, which proceed via the intermediate zwitterionc gold antimonate complex [o-(iPr2P)C6H4)2F3SbPh]Au (6), trigger migration of the phenyl group to gold and afford [(o-(iPr2P)C6H4)2F3Sb]AuPh (7). Because the phenyl group in 7 is orthogonal to that in 3 and opposite to that in 2, the title AuSb platform can be regarded as a molecular analogue of a mechanical three-way switch in which the switching element is a phenyl group. Finally, while all complexes involved retain a Au → Sb interaction, this interaction is no longer present in the zwitterionic derivative 6 because of the neutralization of the Lewis acidity of the antimony center. PMID:27583565

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

    Directory of Open Access Journals (Sweden)

    Annerose Heller

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

  1. 价格歧视抑或价格挤压——辨析中国电信、联通滥用市场支配地位行为之认定%Price discrimination or price squeeze --identification of China telecom and unicom's dominant position abuse

    Institute of Scientific and Technical Information of China (English)

    干潇露

    2012-01-01

    为辨析价格歧视与价格挤压这2种滥用市场支配地位行为之区别,完善《中国人民共和国反垄断-a}立法和执法制度,分析了中国电信行业的现状、电信市场的结构、电信业垄断运营商的定价行为、价格挤压与价格歧视的概念比较、价格挤压的构成要件,并介绍了互联网接入市场价格挤压之国际案件。分析认为:电信、联通对与其有直接竞争关系的运营商和没有竞争关系的经营者、终端用户实行不同接入价格之行为应当被认定为价格挤压行为,而非价格歧视行为。%In order to classify the differences of price discrimination and price squeeze, which are two category of dominant position abuse, and to make contribution to the promotion of China's Anti-mon- opoly Law litigation and enforcement system, this paper analyzed the status quo of Chinese telecommuni- cation industry, its structure, the pricing act of monopolistic operator, the definition comparison of price discrimination and price squeeze, the factors contributed to price squeeze and relevant international cases in this area. The result indicates that China telecom's and unicom's act should be taken as prize squeeze rather than price discrimination when they enact higher price of internet access for other ISPs who directly compete with China telecom and unicom in retail market.

  2. In vivo/In vitro immune responses to L. major isolates from patients with no clinical response to Glucantime

    Science.gov (United States)

    Saberi, Sedigheh; Arjmand, Reza; Soleimanifard, Simindokht; Khamesipour, Ali; Hosseini, Seyed Mohsen; Salehi, Mansoor; Varshosaz, Jaleh; Palizban, Abbas Ali; Hejazi, Seyed Hossein

    2016-01-01

    Background: Leishmaniasis is a major health problem in some endemic areas of tropical and subtropical areas of the world. Interleukin-12 (IL-12) and interferon gamma (IFN-γ) are essential cytokines associated with initiation of Th1 response. The main objective of this study was to evaluate of the type of immune response to L. major isolates from patients with no clinical response to antimonite (Glucantime). Materials and Methods: This experimental study was carried out during 2013–2014. In the current study Leishmania major were isolated from 10 CL patients with a history of at least one course of treatment with Meglumine antimonate (Sb5). The isolates were used to evaluate in vitro and in vivo response to Sb5. J774 murine macrophage cell line was used for in vitro tests and Balb/c mice was used for in vivo studies. IL-12 gene expression was evaluated using Real-time PCR and IFN-γ serum level was quantified using ELISA technique. SPSS (version: 20), analysis of Covariance (ANCOVA) was used for statistical analysis. Results: PCR results confirmed that all 10 isolates were L. major. The mean of IL-12 gene expression in vitro, in vivo and IFN-γ serum levels (pg/ml) after 2 and 3 weeks treatment in vivo, increased significantly following the treatment with Glucantime in the two groups of Balb/c mice infected either with patients' isolates or standard L. major. No significant difference was seen between the patients' isolates and standard species. Conclusions: Although the L. major were isolated from patients with active lesion and no clinical response to Glucantime after at least one courses of Glucantime treatment but in vivo and in vitro immune response of L. major isolates showed no difference between the patients' isolates and standard L. major. PMID:27563636

  3. Preparation and application of aqueous organosilicon-modified polyester resin%水性有机硅改性聚酯树脂的合成与应用

    Institute of Scientific and Technical Information of China (English)

    张丽丽; 曾敬荣; 江俊鸿; 杨雁; 俞金柱

    2013-01-01

    In this paper, hydroxy polyester resins were synthesized through melting. In this process, anti-monous oxide was used as catalyst and 10%, 30% and 50% of organosilicon intermediate was used to chemical modification respectively. The modified organosilicon polyester resin with trimellitic anhydride was processed with water base-side processing,then salted with dimethylethanolamine. This kind of water-soluble organosilicon modified polyester resin treated with this way was used to cure and film with amino resin, which performs excellent high temperature resistant, high solidity and excellent flexibility. The experiment results showed that the compositive property and the price performance is the best when the content of organosilicon is 30%.%本文以Sb2O3为催化剂,采用熔融法合成端羟基聚酯树脂,分别以10%、30%、50%的有机硅中间体进行化学改性,以偏苯三甲酸酐对有机硅改性后的聚酯进行了水性化封端,并采用二甲基乙醇胺成盐,制备的水性有机硅改性聚酯树脂配以氨基树脂固化成膜后,表现出具有优良耐高温性、高硬度、良好柔韧性等性能,实验表明,当有机硅含量为30%时,改性聚酯树脂树脂的综合性能和性价比最好.

  4. Obtaining membranes for alternative treatment hydrogels of cutaneous leishmaniasis; Obtencao de membranas de hidrogeis para tratamento alternativo da leishmaniose tegumentar

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Maria Jose Alves de

    2013-07-01

    Polymeric Hydrogels formed by crosslinked polymeric chains were obtained by ionizing radiation process according to Rosiak technique. In the last 40 years the use of hydrogels has been investigated for various applications as curatives. In this work hydrogel membranes were synthesized with poly (N-2-pyrrolidone) (PVP), poly (vinyl alcohol) (PVA), chitosan and laponita clay for use as a vehicle for controlled glucantime release on the surface of skin tissues injured by leishmaniasis. Leishmaniasis is a disease caused by a protozoan parasite of the genus Leishmania transmitted by the bite of phlebotomies sandfly. The traditional treatment of patients infected by these parasites is done with pentavalent antimony in injectable form. However, these antimonates are highly toxic and cause side effects in these patients. In addition, patients with heart and kidney disease can not use this treatment. In treatment with drug delivery hydrogel membrane applied on the surface of leishmaniasis injured tissues the drug is released directly to the wound in a controlled manner, reducing the side effects. Membranes prepared in this study were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG), swelling, gel fraction, infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The characterizations of cytotoxicity and drug release were made 'in vitro' and 'in vivo' with functional test according to ethical protocol of the Division of Infectious and Parasitic Diseases at the Hospital of Clinics, Sao Paulo University-School of Medicine, University. The 'in vivo' test of these membranes proved to be effective in controlled release of drugs directly into leishmaniasis damaged tissues. Results of 'in vivo' tests using PVP/PVAl / clay 1,5% and glucantime membrane showed remarkable contribution to wound reduction and cure in clinical therapy. (author)

  5. Phosphorus removal from aqueous solution using iron coated natural and engineered sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Boujelben, N. [Laboratoire Eau Energie et Environnement, departement de genie geologique, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia)], E-mail: nesrine.boujelben@tunet.tn; Bouzid, J.; Elouear, Z. [Laboratoire Eau Energie et Environnement, departement de genie geologique, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia); Feki, M. [Unite de chimie industrielle I, Ecole Nationale d' Ingenieurs de Sfax, BP W 3038 Sfax (Tunisia); Jamoussi, F. [Laboratoire de Georessources CERTE BP 95, 2050 Hamam-Lif (Tunisia); Montiel, A. [Societe Anonyme de Gestion des Eaux de Paris, 9 rue Schoelcher, 75675 Paris Cedex 14 (France)

    2008-02-28

    New filtration materials covered with metallic oxides are good adsorbents for both cation and anion forms of pollutants. Sfax is one of the most important industrial towns in Tunisia. Its phosphate manufacture in particular is causing considerable amounts of water pollution. Therefore, there is a need to find out a new way of getting rid of this excessive phosphate from water. This work is aimed to examining the potential of three sorbent materials (synthetic iron oxide coated sand (SCS), naturally iron oxide coated sand (NCS) and iron oxide coated crushed brick (CB)) for removing phosphate ions from aqueous solutions. According to our literature survey CB was not used as adsorbent previously. Phosphate ions are used here as species model for the elimination of other similar pollutants (arsenates, antimonates). Optical microscope and scanning electron microscope (SEM) analyses were used to investigate the surface properties and morphology of the coated sorbents. Infra-red spectroscopy and X-ray diffraction techniques were also used to characterize the sorbent structures. Results showed that iron coated crushed brick possess more micro pores and a higher surface area owing to its clay nature. The comparative sorption of PO{sub 4}{sup 3-} from aqueous solutions by SCS, CB and NCS was investigated by batch experiments. The estimated optimum pH of phosphate ion retention for the considered sorbents was 5. The equilibrium data were analysed using the Langmuir and Freundlich isotherms. The sorption capacities of PO{sub 4}{sup 3-} at pH 5 were 1.5 mg/g for SCS, 1.8 mg/g for CB and 0.88 mg/g for NCS. The effect of temperature on sorption phenomenon was also investigated. The results indicated that adsorption is an endothermic process for phosphate ions removal. This study demonstrates that all the considered sorbents can be used as an alternative emerging technology for water treatment without any side effect or treatment process alteration.

  6. Obtaining membranes for alternative treatment hydrogels of cutaneous leishmaniasis

    International Nuclear Information System (INIS)

    Polymeric Hydrogels formed by crosslinked polymeric chains were obtained by ionizing radiation process according to Rosiak technique. In the last 40 years the use of hydrogels has been investigated for various applications as curatives. In this work hydrogel membranes were synthesized with poly (N-2-pyrrolidone) (PVP), poly (vinyl alcohol) (PVA), chitosan and laponita clay for use as a vehicle for controlled glucantime release on the surface of skin tissues injured by leishmaniasis. Leishmaniasis is a disease caused by a protozoan parasite of the genus Leishmania transmitted by the bite of phlebotomies sandfly. The traditional treatment of patients infected by these parasites is done with pentavalent antimony in injectable form. However, these antimonates are highly toxic and cause side effects in these patients. In addition, patients with heart and kidney disease can not use this treatment. In treatment with drug delivery hydrogel membrane applied on the surface of leishmaniasis injured tissues the drug is released directly to the wound in a controlled manner, reducing the side effects. Membranes prepared in this study were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG), swelling, gel fraction, infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The characterizations of cytotoxicity and drug release were made 'in vitro' and 'in vivo' with functional test according to ethical protocol of the Division of Infectious and Parasitic Diseases at the Hospital of Clinics, Sao Paulo University-School of Medicine, University. The 'in vivo' test of these membranes proved to be effective in controlled release of drugs directly into leishmaniasis damaged tissues. Results of 'in vivo' tests using PVP/PVAl / clay 1,5% and glucantime membrane showed remarkable contribution to wound reduction and cure in clinical therapy. (author)

  7. Three-Dimensional Reduced Graphene Oxide Coupled with Mn3O4 for Highly Efficient Removal of Sb(III) and Sb(V) from Water.

    Science.gov (United States)

    Zou, Jian-Ping; Liu, Hui-Long; Luo, Jinming; Xing, Qiu-Ju; Du, Hong-Mei; Jiang, Xun-Heng; Luo, Xu-Biao; Luo, Sheng-Lian; Suib, Steven L

    2016-07-20

    Highly porous, three-dimensional (3D) nanostructured composite adsorbents of reduced graphene oxides/Mn3O4 (RGO/Mn3O4) were fabricated by a facile method of a combination of reflux condensation and solvothermal reactions and systemically characterized. The as-prepared RGO/Mn3O4 possesses a mesoporous 3D structure, in which Mn3O4 nanoparticles are uniformly deposited on the surface of the reduced graphene oxide. The adsorption properties of RGO/Mn3O4 to antimonite (Sb(III)) and antimonate (Sb(V)) were investigated using batch experiments of adsorption isotherms and kinetics. Experimental results show that the RGO/Mn3O4 composite has fast liquid transport and superior adsorption capacity toward antimony (Sb) species in comparison to six recent adsorbents reported in the literature and summarized in a table in this paper. Theoretical maximum adsorption capacities of RGO/Mn3O4 toward Sb(III) and Sb(V) are 151.84 and 105.50 mg/g, respectively, modeled by Langmuir isotherms. The application of RGO/Mn3O4 was demonstrated by using drinking water spiked with Sb (320 μg/L). Fixed-bed column adsorption experiments indicate that the effective breakthrough volumes were 859 and 633 mL bed volumes (BVs) for the Sb(III) and Sb(V), respectively, until the maximum contaminant level of 5 ppb was reached, which is below the maximum limits allowed in drinking water according to the most stringent regulations. The advantages of being nontoxic, highly stable, and resistant to acid and alkali and having high adsorption capacity toward Sb(III) and Sb(V) confirm the great potential application of RGO/Mn3O4 in Sb-spiked water treatment. PMID:27355752

  8. Novel highly selective selective inorganic ion exchangers for the treatment of problematic liquid radwaste

    International Nuclear Information System (INIS)

    Novel highly selective inorganic ion exchange materials have been studied for the removal of radionuclides from diverse liquids such as alpha-bearing scintillation cocktails and acidic decontamination solutions. In addition, the removal of oxo-anionic radionuclides 99Tc (pertechnetate) and 125Sb (antimonate) has been investigated. Large number of ion exchange materials were screened for the removal 241Am by batch experiments (determination of 241Am distribution coefficient) from Wallac HISafe 3 liquid scintillation cocktails. The aquatic phase in the cocktails was either 0.2-0.4 M NaNO3 or HNO3. The liquid scintillation cocktail was studied as such or mixed with methanol, ethanol or propanol diluents. The tentative test comprised the measurement of the distribution coefficient Kd of the tracer batchwise in the various liquids for the different ion exchange materials. In general, the americium uptakes were low (Kd d > 10,000,000 ml/g) for SrTreat material. Further work was carried out with best materials (SrTreat-titanate, antimonysilicate, manganese oxide) to optimise the amount of diluents and to conduct column experiments. It was found that 241Am uptake in the materials increased with increasing dilution until the dilution ratio reached about 1:2. Columns (10 mL) packed with MnO2 and SbSiO2 removed 241Am efficiently from diluted HiSafe liquid with a maximum DF of 60-250. There was no sigh of column exhaustion when 2.5 L (250 BV) of liquid had been processed. A total of 8 L of scintillation liquids were purified in the column tests. In addition, americium-bearing nitric waste liquids (pH = 1.1) were decontaminated successfully using SbSiO2-columns and acid solution was disposed of in the sewer after neutralisation. Also, removal of Co-57 has been studied from acids commonly used for decontamination (oxalic acid, citric acid, formic acid, sulphuric acid and nitric acid) using novel manganese antimonate material. Uptake of Co-57 was more dependent on solution p

  9. [Evaluation of clinical and laboratory findings of adult visceral leishmaniasis cases].

    Science.gov (United States)

    Ural, Serap; Kaptan, Figen; Sezak, Nurbanu; El, Sibel; Örmen, Bahar; Türker, Nesrin; Demirdal, Tuna; Vardar, İlknur; Özkan Çayıröz, Pınar; Çakalağaoğlu, Fulya

    2015-10-01

    either meglumine antimonate (Glucantime(®), 20 mg/kg/day, intramuscularly for 28 days) or liposomal amphotericin B (3 mg/kg/day, intravenously for the first 5 days, then on 14(th) and 21(st) days) according to the availability of drugs. During one year follow-up period all of the patients improved and no recurrence was seen in any patient. In conclusion, among adult patients with fever uncontrolled within 2-week course of ampiric antibiotic treatment without any infectious focus or malignancy, VL should also be considered. PMID:26649416

  10. Antimony and arsenic biogeochemistry in the western Atlantic Ocean

    Science.gov (United States)

    Cutter, Gregory A.; Cutter, Lynda S.; Featherstone, Alison M.; Lohrenz, Steven E.

    The subtropical to equatorial Atlantic Ocean provides a unique regime in which one can examine the biogeochemical cycles of antimony and arsenic. In particular, this region is strongly affected by inputs from the Amazon River and dust from North Africa at the surface, and horizontal transport at depth from high-latitude northern (e.g., North Atlantic Deep Water) and southern waters (e.g., Antarctic Bottom and Intermediate Waters). As a part of the 1996 Intergovernmental Oceanographic Commission's Contaminant Baseline Survey, data for dissolved As(III+V), As(III), mono- and dimethyl arsenic, Sb(III+V), Sb(III), and monomethyl antimony were obtained at six vertical profile stations and 44 sites along the 11,000 km transect from Montevideo, Uruguay, to Bridgetown, Barbados. The arsenic results were similar to those in other oceans, with moderate surface depletion, deep-water enrichment, a predominance of arsenate (>85% As(V)), and methylated arsenic species and As(III) in surface waters that are likely a result of phytoplankton conversions to mitigate arsenate "stress" (toxicity). Perhaps the most significant discovery in the arsenic results was the extremely low concentrations in the Amazon Plume (as low as 9.8 nmol/l) that appear to extend for considerable distances offshore in the equatorial region. The very low concentration of inorganic arsenic in the Amazon River (2.8 nmol/l; about half those in most rivers) is probably the result of intense iron oxyhydroxide scavenging. Dissolved antimony was also primarily in the pentavalent state (>95% antimonate), but Sb(III) and monomethyl antimony were only detected in surface waters and displayed no correlations with biotic tracers such as nutrients and chlorophyll a. Unlike As(III+V)'s nutrient-type vertical profiles, Sb(III+V) displayed surface maxima and decreased into the deep waters, exhibiting the behavior of a scavenged element with a strong atmospheric input. While surface water Sb had a slight correlation with

  11. Removal of Radioactive Nuclides by Multi-Functional Microcapsules Enclosing Inorganic Ion-Exchangers and Organic Extractants

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, H.; Akiba, K.; Onodera, Y.

    2002-02-26

    The microcapsules enclosing two kinds of functional materials, inorganic ion-exchangers and organic extractants, were prepared by taking advantage of the high immobilization ability of alginate gel polymer. The fine powders of inorganic ion-exchanger and oil drops of extractant were kneaded with sodium alginate (NaALG) solution and the kneaded sol readily gelled in a salt solution of CaCl2, BaCl2 or HCl to form spherical gel particles. The uptake properties of various nuclides, 137Cs, 85Sr, 60Co, 88Y, 152Eu and 241Am, for thirty-four specimens of microcapsules in the presence of 10-1-10-4 M HNO3 were evaluated by the batch method. The distribution coefficient (Kd) of Cs+ above 103 cm3/g was obtained for the microcapsules enclosing CuFC or AMP. The Kd of Sr2+ around 102 cm3/g was obtained for the microcapsules containing clinoptilolite, antimonic acid, zeolite A, zeolite X or titanic acid. The microcapsules enclosing DEHPA exhibited relatively large Kd values of trivalent metal ions above 103 cm3/g; for example, the Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ for a favorable microcapsule (CuFC/clinoptilolite/DEHPA/CaALG) were 1.1x104, 7.5x10, 1.1x10, 1.0x104, 1.4x104, 3.4x103 cm3/g, respectively. The uptake rates of Cs+, Y3+, Eu3+ and Am3+ for this microcapsule were rather fast; the uptake percentage above 90% was obtained after 19 h-shaking and the uptake equilibrium was attained within 1 d. The AMP/CaALG exhibited high uptake ability for Cs+ even after irradiation of 188 kGy, and DEHPA/CaALG microcapsule had similar Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ ions before and after irradiation. The microcapsules with various shapes such as spherical, columnar, fibrous and filmy forms were easily prepared by changing the way of dipping kneaded sol into gelling salt solution. The microcapsules enclosing inorganic ion-exchangers and extractants have a potential possibility for the simultaneous removal of various radioactive nuclides from waste solutions.

  12. Immobilization of antimony in waste-to-energy bottom ash by addition of calcium and iron containing additives.

    Science.gov (United States)

    Van Caneghem, Jo; Verbinnen, Bram; Cornelis, Geert; de Wijs, Joost; Mulder, Rob; Billen, Pieter; Vandecasteele, Carlo

    2016-08-01

    The leaching of Sb from waste-to-energy (WtE) bottom ash (BA) often exceeds the Dutch limit value of 0.32mgkg(-1) for recycling of BA in open construction applications. From the immobilization mechanisms described in the literature, it could be concluded that both Ca and Fe play an important role in the immobilization of Sb in WtE BA. Therefore, Ca and Fe containing compounds were added to the samples of the sand fraction of WtE BA, which in contrast to the granulate fraction is not recyclable to date, and the effect on the Sb leaching was studied by means of batch leaching tests. Results showed that addition of 0.5 and 2.5% CaO, 5% CaCl2, 2.5% Fe2(SO4)3 and 1% FeCl3 decreased the Sb leaching from 0.62±0.02mgkgDM(-1) to 0.20±0.02, 0.083±0.044, 0.25±0.01, 0.27±0.002 and 0.29±0.02mgkgDM(-1), respectively. Due to the increase in pH from 11.41 to 12.53 when 2.5% CaO was added, Pb and Zn leaching increased and exceeded the respective leaching limits. Addition of 5% CaCO3 had almost no effect on the Sb leaching, as evidenced by the resulting 0.53mgkgDM(-1) leaching concentration. This paper shows a complementary enhancement of the effect of Ca and Fe, by comparing the aforementioned Sb leaching results with those of WtE BA with combined addition of 2.5% CaO or 5% CaCl2 with 2.5% Fe2(SO4)3 or 1% FeCl3. These lab scale results suggest that formation of romeites with a high Ca content and formation of iron antimonate (tripuhyite) with a very low solubility are the main immobilization mechanisms of Sb in WtE BA. Besides the pure compounds and their mixtures, also addition of 10% of two Ca and Fe containing residues of the steel industry, hereafter referred to as R1 and R2, was effective in decreasing the Sb leaching from WtE BA below the Dutch limit value for reuse in open construction applications. To evaluate the long term effect of the additives, pilot plots of WtE BA with 10% of R1 and 5% and 10% of R2 were built and samples were submitted to leaching tests at

  13. Platinum mineralization in the Kapalagulu Intrusion, western Tanzania

    Science.gov (United States)

    Wilhelmij, Harry R.; Cabri, Louis J.

    2016-03-01

    . Impersistent, stratiform PGE mineralized horizons occur within the MCSS harzburgite from which drill core samples were taken for platinum-group mineral (PGM) characterization from two drill holes. Where the PGE reefs reach the surface there is residual PGE mineralization within the laterite regolith from which drill core samples were taken from various laterite lithological units for PGM characterization. As the harzburgite PGE reefs contain significant concentrations of both sulfide and chromite (including chromitite seams) they resemble the PGE-rich chromitite seams of the Bushveld Complex rather than the PGE-bearing Main Sulfide Zone of the Great Dyke and Main Sulfide Layer of the Munni Munni Complex. The dominant Pd PGM in three PGE reef samples varies, ranging ( n = 164, relative wt%) from bismuthides (63 %), bismuthtellurides (19 %), and tellurides (6 %), to tellurides (39 %), bismuthtellurides (24 %), stannides (14 %), and alloys (13 %), and to antimon-arsenides (33 %), stannides (21 %), bismuthides (17 %), tellurides (13 %), and alloys (10 %). From 13.5 % to 21.0 % of the total Pd occurs as a solid solution in pentlandite. The three samples have similar Pt PGM modal distributions ( n = 172, relative wt%); the dominant Pt mineral is sperrylite (79, 58, and 47 %) followed by tellurides (15, 17, 21 %), alloys (2, 1, 1 %), and sulfides (2, 1, 0 %). Comparison of Pd/Pt ratios from assays to those calculated from minerals show that the data for the Pt and Pd PGM are very robust, confirming the concentration methodology and characterization. Study of samples from a shallow drill hole penetrating the laterite regolith shows that the primary Pd mineralization has not survived oxidation, is mainly dispersed, but some was reconstituted to form secondary minerals: cabriite, unnamed tellurides, a selenide, a Pd-Te-Hg mineral, alloys and Pd-bearing secondary sulfides (millerite and heazlewoodite). The primary Pt minerals are more resistant to oxidation and dissolution, especially

  14. Ligand influences on properties of uranium coordination complexes. Structure, reactivity, and spectroscopy

    International Nuclear Information System (INIS)

    In this thesis several different aspects of uranium chemistry are presented. It was shown that terminal uranium(V) oxo and imido complexes [((RArO)3tacn)UV(O)] and [((RArO)3tacn)UV(NSiMe3)] (R = t Bu, Ad) can be oxidized by silver(I) hexafluoro-antimonate to the uranium(VI) oxo and imido complexes [((RArO)3tacn)UVI(O)]SbF6 and [((RArO)3tacn)UVI(NSiMe3)]SbF6. While for the t Bu-derivative of the oxo complex an equatorial coordination is observed due to stabilization by the inverse trans-influence, normal axial coordination is observed for the Ad-derivative and both imido complexes. The inverse trans-influence was thus proven to be a key factor for the coordination mode of a terminal ligand on high valent uranium complexes. LIII XANES was shown to be a great tool for the determination of oxidation states of uranium complexes. Therefore, a series of uranium complexes in all stable oxidation states for uranium, +III to +VI was prepared, and their spectra analyzed. All compounds bear only O-donor ligands in addition to the chlating trisaryloxide-tacn-ligand. A separation of 1.5 to 3 eV in the white line energy is observed between the different oxidation states. This series can be used as reference for compounds, where oxidation state assignment is not obvious, such as a ketyl radical complex [((t-BuAr)O3tacn)U(O-C(t-BuPh)2.-)]. For this complex, the oxidation state of +IV could be assigned. Moreover, a series of isostructural uranium(IV) complexes was prepared. The influence of different ligands according to the spectrochemical series on the electronic and magnetic properties could be shown using UV/vis/NIR spectroscopy and variable temperature SQUID measurements. Calculations of uranium LIII XANES spectra show a variation in the shape of the spectra and thus high resolution PFY-XANES would be a great tool to determine the electronic influence of these different axial ligands. Using the single N-anchored ligand system, the first example of a uranium(IV)

  15. 高铅铜阳极泥的工艺矿物学

    Institute of Scientific and Technical Information of China (English)

    杨洪英; 李雪娇; 佟琳琳; 陈国宝

    2014-01-01

    In order to improve the technology of the process of noble metal extracted from high lead copper anode slime, the process mineralogy was investigated by XRD, SEM and microscope. The particle size of high lead anode slime is small, and the composition is complex. The main noble metals are Au 0.33%, Ag 9.94%and Pd 0.1%(mass fraction), and the main base metals are Cu 16.35%and Pb 13.74%. The chief phases include Au and gold­lead alloy, eukairite, sulfate, arsenate, antimonate and oxygen. The results show that there are two main phases of gold as elemental gold and gold­lead alloy with the mass ratio of approximately 3:1. The particle size is uneven, the biggest particle size is about 15μm and the smallest one is about 0.1μm. The elemental Au is often wrapped in copper sulfate, so, Cu should be removal before extracting Au. Ag exists in silver selenide and eukairite. Three elements are miscible and form a solid solution. Cu and Pb are major base metal. Cu exists in Cu, copper sulphate, eukairite and chalcopyrite. Pb exists in lead sulfate, lead antimonite, lead arsenate and lead sulphide. Arsenic antimony bismuth compounds mainly include lead antimonite, bismuth arsenate and antimony arsenate. The characteristics of the structure indicates that bought­out anode slime structured on copper sulphate, nickel oxide constantly wrapped copper, antimony arsenate constantly wrapped chalcopyrite, barium sulfate and lead sulfate constantly growed interactively.%为了高效回收高铅铜阳极泥中贵金属,改进阳极泥的现行生产工艺,采用XRD、SEM和显微镜等对阳极泥进行工艺矿物学研究。结果表明:阳极泥的颗粒较细,成分复杂,贵金属主要为Au 0.33%、Ag 9.94%、Pd 0.1%(质量分数);贱金属主要为Cu 16.35%、Pb 13.74%。主要物相包括金以及金铅合金、铜银硒化合物、硫酸盐、砷酸盐、锑酸盐以及氧化物。分析得知,金主要有单质金以及金铅合金两种